EP0747598B1

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Publication number: EP0747598B1
Application number: EP19960304219
Authority: EP
Inventors: Mark Bass; Roy J. Doepker; Jean-Luc M. Caillat; Wayne R. Warner
Original assignee: Copeland Corp LLC
Current assignee: Copeland Corp LLC
Priority date: 1995-06-07
Filing date: 1996-06-06
Publication date: 2005-09-14
Anticipated expiration: 2016-06-06
Also published as: DE69635176T2; DE69635176D1; ES2247600T3; EP0747598A3; EP0747598A2

Description

Background and Summary of the Invention

The present invention is related to capacity modulation of compressorsand more particularly to capacity modulation of scroll-type compressors.
Capacity modulation is often a desirable feature to incorporate in airconditioning and refrigeration compressors in order to better accommodate the widerange of loading to which the systems may be subjected. Many different approacheshave been utilized for providing this capacity modulation feature ranging fromcontrolling of the suction inlet to bypassing discharge gas back to the suction inlet.With scroll-type compressors, capacity modulation has often been accomplished viaa delayed suction approach which comprises providing ports at various positionswhich, when opened, allow the compression chambers formed between theintermeshing scroll wraps to communicate with the suction gas supply therebydelaying the point at which compression of the suction gas begins. This method ofcapacity modulation actually reduces the compression ratio of the compressor. Whilesuch systems are effective at reducing the capacity of the compressor, they are onlyable to provide a predetermined amount of compressor unloading, the amount ofunloading being dependent upon the positioning of the unloading ports along thewraps. While it is possible to provide multiple step unloading by incorporating aplurality of such ports at different locations, this approach becomes costly andrequires additional space to accommodate the separate controls for opening andclosing each set of ports.
WO 86/01262 upon which the precharacterizing portion ofappendedclaim 1 is based, describes a positive displacementcompressor or pump of the scroll type including first and secondscroll plates having convoluted interfitting vanes. The flanks of the vanes on scroll plates are interfitting and in sealingcontact with one another and the tips of the vanes in sealingcontact with the other plate. One of the plates has a generallycentral port and the assemblage is provided with a peripheralport at the interface of the plates. A motor and linkage areprovided to cause the plates to undergo orbital movementrelative to each other and a selectivity operable mechanism isoperable to separate the plates to break sealing contact andthereby unload the compressor or pump.
The various embodiments of the present invention,however, overcome deficiencies noted above in that-theyenable virtually a continuous range of unloading from 100percent or full capacity down to virtually zero capacityutilizing only a single set of controls. Further, theyenable the operating efficiency of the compressor and/orrefrigeration system to be maximized for any degree ofcompressor unloading desired.
According to the present invention, there is provided ascroll-type machine as defined in appendedclaim 1.
In the various embodiments of the present invention,compressor unloading is accomplished by cyclically effecting axial or radial separation of the two scroll members forpredetermined periods of time during the operating cycle of the compressor. Morespecifically, the present invention provides an arrangement wherein one scrollmember is moved axially or radially toward and away from the other scroll memberin a pulsed fashion to cyclically provide a leakage path across the tips or flanks ofthe wraps from higher pressure compression pockets defined by the intermeshingscroll wraps to lower pressure pockets and ultimately back to suction. By controllingthe relative time between sealing and unsealing of the scroll wrap tips or flanks,virtually any degree of compressor unloading can be achieved with a single controlsystem. Further, by sensing various conditions within the refrigeration system, theduration of compressor loading and unloading for each cycle can be selected for agiven capacity such that overall system efficiency is maximized. For example, if it isdesired to operate the compressor at 50 percent capacity, this can be accomplishedby operating the compressor alternately in a loaded condition for five seconds andunloaded for five seconds or loaded for seven seconds and unloaded for sevenseconds, one or the other of which may provide greater efficiency for the specificoperating conditions being encountered.
The various embodiments of the present invention described belowprovide a wide variety of arrangements by which one scroll member may be axiallyor radially reciprocated with respect to the other to accommodate a full range ofcompressor unloading. The ability to provide a full range of capacity modulation witha single control system as well as the ability to select the duration of loaded and unloaded operation cooperate to provide an extremely efficient system at a relativelylow cost.
Additionally, in order to even further improve system efficiency in someapplications, it may be desirable to combine a delayed suction type of capacitymodulation with the pulsed unloading approach mentioned above. For example,when operating conditions are such that system pressures just downstream of thedischarge valve are at a level below the full load design level, the compression ratioof the compressor will result in pressure of the compressed fluid as it is dischargedfrom the compression chamber being too high, a condition known asover-compression. The most efficient way to reduce capacity under these conditionsis to reduce the compression ratio of the compressor and hence the pressure of thecompressed fluid exiting the compression chamber such that it is equal to or onlyslightly above the system pressure just downstream of the discharge valve thuseliminating the lost work due to over-compression. However, if a further reductionin capacity is indicated by system condition once the over-compression condition hasbeen eliminated, the use of a pulsed type of capacity modulation will be more efficientas it will avoid creation of a condition known as under-compression, that being asituation where the pressure of the compressed fluid as it leaves the compressionchamber being below that of the system just downstream of the discharge valve.Thus, the present invention also includes a system in which both pulsed and delayedsuction capacity modulation approaches are combined which result in even greaterefficiencies for systems likely to encounter such operating conditions than could beachieved by either of the two capacity modulation approaches alone.
Additionally, the present invention may also incorporate a motor controlmodule which will operate to control various operating parameters thereof to enhance its operating efficiency during periods when the motor load is reduced due tounloading of the compressor.
Additional advantages and features of the present invention will becomeapparent from the subsequent description and the appended claims taken inconjunction with the accompanying drawings.

Brief Description of the Drawings

Figure 1 is a section view of a scroll-type refrigeration compressor inaccordance with the present invention;
Figure 2 is a fragmentary section view of a scroll-type refrigerationcompressor showing another embodiment of the present invention;
Figure 3 is a view similar to that of Figure 2 but showing the compressorin an unloaded condition;
Figure 4 is a fragmentary section view of a scroll-type refrigerationcompressor showing a further embodiment of the present invention;
Figure 5 is an enlarged view of the valve arrangement incorporated in theembodiment shown in Figure 4;
Figure 6 is also a fragmentary section view of a scroll-type refrigerationcompressor showing another embodiment of the present invention;
Figures 7 through 15 are all fragmentary section views of refrigerationcompressors in accordance with the present invention in which the orbiting scrollmember is axially reciprocated to accomplish compressor unloading;
Figures 16 through 22 are all fragmentary section views of refrigerationcompressors in accordance with the present invention in which the non-orbiting scrollmember is axially reciprocated to accomplish compressor unloading;
Figures 23 through 28 are all fragmentary section views of refrigerationcompressors in accordance with the present invention in which the scroll membersare co-rotating;
Figures 29 through 30 are both fragmentary section views of additionalembodiments of refrigeration compressors all in accordance with the presentinvention in which the non-orbiting scroll member is reciprocated; and
Figure 31 is a section view of yet another embodiment of a scroll-typecompressor in accordance with the present invention adapted to be driven by anexternal power source;
Figures 32 through 34 are fragmentary section view of otherarrangements of scroll-type compressors ;
Figure 34A is an enlarged fragmentary view of the valving arrangementshown in Figure 34 and enclosed withincircle 34A;
Figure 35 is a fragmentary section view of a further arrangement of ascroll-type compressor ;
Figure 36 is also a fragmentary section view of yet a further embodimentof the present invention showing an arrangement for radially unloading of thecompressor in accordance with the present invention;
Figure 37 is a section view of the crank pin and drive bushing employedin the embodiment of Figure 36, the section being taken along lines 37-37 thereof;
Figure 38 is a section view of the embodiment shown in Figure 36, thesection being taken along lines 38-38 thereof;
Figure 39 is a view similar to that of Figure 36 but showing thecompressor in an unloaded condition;
Figure 40 is a fragmentary section view showing a modified version ofthe embodiment of Figure 36, all in accordance with the present invention;
Figure 41 is a fragmentary section view showing a portion of a scroll-typecompressor incorporating another embodiment of the radial unloading arrangementof Figure 36, all in accordance with the present invention;
Figure 42 is a section view similar to that of Figure 38 but showing theembodiment of Figure 41;
Figure 43 is a fragmentary section view showing yet another embodimentof the present invention;
Figure 44 is a view of a portion of the embodiment shown in Figure 43in an unloaded condition;
Figure 45 is a schematic showing a means for reducing motor powerconsumption during periods when the compressor is operating in an unloadedcondition in accordance with the present invention; and
Figure 46 is a section view of a compressor incorporating both cyclicalscroll wrap separation and delayed suction unloading, all in accordance with thepresent invention.

Description of the Preferred Embodiments

Referring now to the drawings and in particular to Figure 1, there isshown a hermetic scroll compressor in accordance with the present inventionindicated generally at 10.Scroll compressor 10 is generally of the type described inassignee's U.S. Patent No. 5,102,316, the disclosure of which is incorporated byreference, and includes anouter shell 12 within which is disposed a drivingmotorincluding stator 14 androtor 16, acrankshaft 18 to whichrotor 16 is secured, upperand lower bearinghousings 20, 22 for rotatably supportingcrankshaft 18 andcompressor assembly 24.
Compressor assembly 24 includes an orbitingscroll member 26supported on upper bearinghousing 20 and drivingly connected tocrankshaft 18 viacrank pin 28 and drive bushing 30. A secondnon-orbiting scroll member 32 ispositioned in meshing engagement withscroll member 26 and axially movablysecured to upper bearinghousing 20 by means of a plurality ofbolts 34 andassociatedsleeve members 36. An Oldhamcoupling 38 is provided whichcooperates betweenscroll members 26 and 32 to prevent relative rotationtherebetween.
Apartition plate 40 is provided adjacent the upper end ofshell 12 andserves to define adischarge chamber 42 at the upper end thereof.
In operation, as orbitingscroll member 26 orbits with respect toscrollmember 32, suction gas is drawn intoshell 12 viasuction inlet 44 and thence intocompressor 24 throughinlet 46 provided innon-orbiting scroll member 32. Theintermeshing wraps provided onscroll members 26 and 32 define moving fluidpockets which progressively decrease in size and move radially inwardly as a resultof the orbiting motion ofscroll member 26 thus compressing the suction gas enteringviainlet 46. The compressed gas is then discharged intodischarge chamber 42 viadischarge port 48 provided inscroll member 32 andpassage 50. A suitable pressureresponsive discharge valve 51 is preferably provided seated withindischarge port 48.
Scrollmember 32 is also provided with an annularcylindrical recess 52formed in the upper surface thereof. One end of a generally irregularly shapedcylindrical member 54 within whichpassage 50 is provided projects intocylinder 52and divides same into upper andlower chambers 56 and 58. The other end ofcylindrical member 54 is sealingly secured topartition plate 40. Anannular ring 60is secured to the upper end ofscroll member 32 and includes anaxially extending flange 62 slidingly engageable withcylinder member 54 to thereby seal off the openupper end ofchamber 56.
Cylindrical member 54 includes apassage 64 having one end whichopens intoupper chamber 56. Afluid line 66 is connected to the other end ofpassage 64 and extends outwardly throughshell 12 to a solenoid operatedvalve 68.Asecond fluid line 70 extends fromvalve 68 tosuction line 72 connected tosuctioninlet 44 and athird fluid line 74 extends fromvalve 68 to adischarge line 76extending outwardly fromdischarge chamber 42.
In order to biasscroll member 32 into sealing engagement withscrollmember 26 for normal fully loaded operation, ableed hole 78 is provided inscrollmember 32 communicating betweenchamber 58 and a compression pocket at anintermediate pressure between suction and discharge pressure. Thus,chamber 58will be at an intermediate pressure which together with the discharge pressure actingon the upper surface ofscroll member 32 in the area ofdischarge port 48 will exerta biasing force on scroll member urging it axially into sealing engagement withorbitingscroll member 26. At the same time,solenoid valve 68 will be in a positionso as to placeupper chamber 56 in fluid communication withsuction line 72 viafluidlines 66 and 70.
In order to unloadcompressor 24,solenoid valve 68 will be actuated inresponse to a signal fromcontrol module 80 to interrupt fluid communication betweenlines 66 and 70 and to placefluid line 66 in communication withdischarge line 76thus increasing the pressure withinchamber 56 to that of the discharge gas. Thebiasing force resulting from this discharge pressure will overcome the sealing biasingforce thereby causingscroll member 32 to move axially upwardly away from orbitingscroll member 26. This axial movement will result in the creation of a leakage pathbetween the respective wrap tips and end plates ofscroll members 26 and 32 thereby substantially eliminating continued compression of the suction gas. Whenunloading occurs,discharge valve 51 will move to a closed position therebypreventing the back flow of high pressure fluid fromdischarge chamber 42 or thedownstream system. When compression of the suction gas is to be resumed,solenoid valve 68 will be actuated to a position in which fluid communication betweenupper chamber 56 anddischarge line 76 vialines 66 and 74 is interrupted andupperchamber 56 is placed in communication withsuction line 72 viafluid lines 66 and 70thereby relieving the axially directed separating force. This then allows thecooperative action of the intermediate pressure inchamber 58 and dischargepressure acting inpassage 50 to again movescroll member 32 into sealingengagement withscroll member 26.
Preferably,control module 80 will have one or moreappropriate sensors82 connected thereto to provide the required information forcontrol module 80 todetermine the degree of unloading required for the particular conditions existing atthat time. Based upon this information,control module 80 will send appropriatelytimed sequential signals tosolenoid valve 68 to cause it to alternately placefluid line66 in communication withdischarge line 76 andsuction line 72. For example, ifconditions indicate that it is desirable to operatecompressor 24 at 50 percent of fullcapacity,control module 80 may actuate solenoid valve to a position to placefluidline 66 in communication withsuction line 72 for a period of say 10 secondswhereupon it is switched to placefluid line 66 in fluid communication withdischargeline 76 for a like period of 10 seconds. Continued switching ofsolenoid valve 68 inthis manner will result in compression occurring during only 50 percent of theoperating time thus reducing the output ofcompressor 24 to 50 percent of its fullload capacity. As the sensed conditions change, control module will vary the relativetime periods at whichcompressor 24 is operated in a loaded and unloaded condition such that the capacity ofcompressor 24 may be varied between fully loaded or 100percent capacity and completely unloaded or 0 percent capacity in response tovarying system demands.
Figures 2 and 3 show an axialunloading scroll compressor 34 similar tothat of Figure 1 with the primary exception being the arrangement for placingupperchamber 56 in fluid communication with suction and discharge lines. Accordingly,like portions have been indicated by the same reference numbers. As shown therein,passage 64 has been replaced by apassage 86 provided inannular member 60which opens at one end intoupper chamber 56 and at the other end through aradially outwardly facing sidewall. Aflexible fluid line 88 extends from the outer endofpassage 86 to a fitting 90 extending throughshell 12 with asecond line 92connecting fitting 90 tosolenoid valve 68. As with Figure 1,solenoid valve 68 hasfluid lines 70 and 74 connected tosuction line 72 anddischarge line 76 and iscontrolled bycontrol module 80 in response to conditions sensed bysensor 82 toeffect movement ofnon-orbiting scroll member 32 between the positions shown inFigures 2 and 3 in the same manner as described above with respect to theembodiment of Figure 1. While this embodiment eliminates the need for an extrafitting extending outwardly from the highpressure discharge chamber 42, it requiresthatfluid conduit 88 be flexible so as to accommodate axial movement ofscrollmember 32 and associatedannular member 60. It should also be noted that in thisembodimentcylindrical member 54 is sealingly secured topartition plate 40 by meansofnut 55 which threadedly engages the upper end thereof. Also in this embodiment,discharge valve 51 has been replaced by adischarge check valve 93 secured to theouter shell. It should be noted that the provision of a check valve some place alongthe discharge flowpath is highly desirable in order to prevent back flow ofcompressed gas from the system when the compressor is in an unloaded condition.
Figures 4 and 5 show anotherembodiment 94 of the present inventionin which axial unloading separating pressure fluid is provided directly from thedischarge gas exiting the compressor. In this embodiment, atubular member 96 issuitably secured topartition member 40 and includes a radially outwardly extendingflange 98 which is positioned in and separates cylindrical recess into upper andlowerchambers 56 and 58.Tubular member 96 also definespassage 50 for directingcompressed discharge gas fromport 48 to dischargechamber 42. An axialextendingbore 100 is provided in tubular member which opens outwardly throughthe upper end thereof and is adapted to receive afluid conduit 102.Fluid conduit102 extends outwardly through the top ofshell 12 and is connected to solenoidvalve68. Solenoid valve also hasfluid conduits 70 and 74 connected to respective suctionanddischarge lines 72, 76 and is controlled bycontrol module 80 in response tosignals fromappropriate sensors 82 in the same manner as described above.
Avalve member 104 is axially movably disposed withinbore 100.Valvemember 104 includes a reduceddiameter portion 106 operative to place radiallyextendingpassages 108 and 110 provided inmember 96 in fluid communicationwhen in a first position so as to ventupper chamber 56 to suction and to placeradialfluid passage 110 in fluid communication withradial fluid passage 112 when in asecond position so as to admit discharge gas fromdischarge flowpath 50 toupperchamber 56. Avent passage 113 is also provided which communicates between thebottom ofbore 100 andpassage 50 to vent gas from the area belowvalve 104 duringoperation thereof. Aspring 114 is also provided which serves to aid in biasingvalve104 into its second position whereas pressurized discharge fluid entering bore 100viapassage 112 andpassage 113 serves to biasvalve member 104 into its firstposition.
As shown,valve member 104 andsolenoid valve 68 are both in aposition for fully loaded operation whereinsolenoid valve 68 is in position to placefluid conduit 102 in communication with thesuction line 72 andvalve member 104is in a position to ventupper chamber 56 to the interior ofshell 12 which is at suctionpressure. When it is desired to unload the compressor,solenoid valve 68 will beactuated to a position to placefluid line 102 in communication withfluid line 74thereby enabling pressurized discharge fluid to act on the upper end ofvalve member104. This pressurized fluid together withspring 114 will causevalve member 104 tomove downwardly thereby closing off communication ofradial passage 110 withradial passage 108 and opening communication betweenradial passage 110 andradial passage 112. Discharge pressure fluid will then flow intoupper chamber 56thus overcoming the intermediate pressure biasing force resulting from thecommunication ofchamber 58 with a compression chamber at intermediate pressureviapassage 78 and causingscroll member 32 to move axially upwardly away fromorbitingscroll member 26. It should be noted that the relatively short flowpath forsupplying discharge pressure fluid toupper chamber 56 ensures rapid unloading ofthe compressor.
Figure 6 shows a modified embodiment similar to that of Figures 4 and5 except thatsolenoid valve 68 is positioned withinshell 12. This embodimenteliminates the need for an additional fluid conduit through the high pressure portionof the shell, requiring only an electrical feed for actuatingsolenoid valve 68. In allother respects, construction and operation of this embodiment is substantially thesame as that described above with respect to the embodiment shown in Figures 4and 5 and accordingly corresponding portions are indicated by the same referencenumbers.
While the previously described embodiments have been directed tounloading arrangements wherein the non-orbiting scroll has been moved axially awayfrom the orbiting scroll, it is also possible to apply these same principles to theorbiting scroll. Figures 7 through 15 described below illustrate such a series ofembodiments.
Referring now to Figure 7, ascroll compressor 140 is shown which issimilar to the scroll compressors described above except thatnon-orbiting scrollmember 142 is non-movably secured to bearinghousing 144 and orbitingscrollmember 146 is axially movable. It is also noted thatcompressor 140 is a high sidemachine, that is, thesuction inlet 149 is directly connected to thenon-orbiting scrollmember 142 and the interior of theshell 12 is at discharge pressure. In thisembodiment, orbitingscroll member 146 is axially movable and is biased intoengagement withnon-orbiting scroll 142 by means of apressure chamber 148defined between orbitingscroll member 146 andmain bearing housing 144. Anannular recess 150 is provided inmain bearing housing 144 in which is disposed asuitable annularresilient seal member 152 which sealingly engages the lower surfaceof orbitingscroll member 146 so as to prevent fluid communication betweenchamber148 and the interior ofshell 12 which is at discharge pressure. A secondannular seal154 is provided onmain bearing housing 144 surroundingshaft 18 to prevent fluidleakage therealong. Asmall passage 156 is provided through the end plate oforbitingscroll member 146 to placechamber 148 in fluid communication with acompression chamber at a pressure intermediate suction and discharge pressure.Additionally, apassage 158 in main bearing housing extends outwardly fromchamber148 and has one end offluid line 160 connected thereto. The other end offluid line160 extends outwardly throughshell 12 and is connected tosolenoid valve 162. Asecond fluid line 164 extends betweensolenoid valve 162 andsuction line 148.
In operation,chamber 148 will be supplied with fluid at intermediatepressure to thereby bias orbitingscroll 146 into sealing engagement withnon-orbitingscroll 142. At this time,solenoid valve 162 will be in a position to prevent fluidcommunication betweenlines 160 and 164. In order to unloadcompressor 140,solenoid valve 162 is actuated to a position to placeline 160 in fluid communicationwithfluid line 164 thereby venting the intermediate pressure inchamber 148 tosuction. The pressure within the compression pockets will then cause orbitingscrollmember 146 to move axially downwardly as shown compressingresilient seals 152and thereby forming a leakage path across the respective wrap tips and associatedend plates of the orbiting andnon-orbiting scroll members 146, 142. Whilepassage156 may continue to provide fluid at a pressure somewhat higher than suctionpressure tochamber 148, the relative sizing ofpassage 158,fluid lines 160 and 164andpassage 158 will be such that there will be insufficient pressure inchamber 148to bias orbitingscroll member 146 into sealing engagement withnon-orbiting scrollmember 142 so long assolenoid valve 162 is in a position to maintain fluidcommunication betweensuction line 149 andchamber 148.Solenoid valve 162 willbe cycled between open and closed positions so as to cyclically load and unloadcompressor 140 in substantially the same manner as described above.
Figure 8 shows a modified version 140a of the embodiment of Figure 7wherein a plurality ofsprings 166 are provided.Springs 166 are seated inrecesses168 provided in bearinghousing 144a and bear against the end plate of orbitingscroll 146 so as to assist in urging orbiting scroll into sealing engagement withnon-orbiting scroll 142.Springs 166 serve primarily to provide an initial biasing forcefor orbitingscroll member 146 on initial start up of compressor 140a but will alsoassist in providing more rapid loading of compressor 140a upon closing ofsolenoidvalve 162 during operation.
Figure 9 shows afurther modification 140b of the embodiments ofFigures 7 and 8. In thisembodiment shell 12 is provided with apartition member 170to separate the interior thereof into a highpressure discharge chamber 172 to whichdischarge port 174 is connected viaconduit 176 and a low suction pressure chambertherebelow within which the compressor is disposed. Additionally, in thisembodiment shaft seal 154 has been replaced with a secondannular seal 178positioned radially inwardly and concentric withseal 150b. Thus the area in whichcrankpin 28 and drivebushing 30 are located will be at suction pressure to therebyavoid any problems associated with providing lubrication thereto from the oil sumpwhich is also at suction pressure. It should be noted that the oil sump in theembodiments of Figures 7 and 8 was at discharge pressure and hence do notpresent any problems with respect to supplying of lubricant to these drivecomponents.
Theembodiment 140c of Figure 10 is substantially identical to that ofFigure 9 with the exception that in addition to the biasing force resulting fromintermediate fluid pressure inchamber 148b, a plurality ofsprings 180 are alsoprovided being positioned between orbitingscroll member 156 andmain bearinghousing 144 and functioning primarily to assist during start up but also to assist inreloading ofcompressor 140c similar to that described above with reference toFigure 8.
In the embodiment of Figure 11,non-orbiting scroll member 182 isprovided with anannular recess 184 within which an annular ring-shapedpistonmember 186 is movably disposed. The lower surface ofannular piston member 186bears against a radially outwardly extending portion 187 ofend plate 189 of orbitingscroll member 146 and radially inner and outerannular seals 188, 190 are providedthereon which sealingly engage radially inner and outer walls ofrecess 184. Aradially extending passage 192 provided innon-orbiting scroll member 182communicates with the upper portion ofrecess 184 and hasfluid conduit 194connected to the outer end thereof.Fluid conduit 194 extends outwardly throughshell 12 tosolenoid valve 196. A secondfluid conduit 198 connectssolenoid valve196 tosuction line 200 whereas a thirdfluid conduit 202 connectssolenoid valve 196to dischargeline 204.
Under normal fully loaded operating conditions, orbitingscroll member146 will be axially biased into sealing engagement withnon-orbiting scroll member182 by intermediate fluid pressure inchamber 206 admitted thereto viableedpassage 208. At this time, the area ofrecess 184 disposed aboveannular pistonmember 186 will be vented to suction viasolenoid valve 196 andconduits 194 and198. When conditions indicate partial unloading of the compressor is desirable,solenoid valve 196 will be actuated to placefluid conduit 194 in fluid communicationwithdischarge line 204 viaconduit 202. The area aboveannular piston 186 will thenbe pressurized by fluid at discharge pressure thereby causing orbitingscroll member146 to be biased axially downwardly as shown. As noted above, cyclical switchingofsolenoid valve 196 will result in repetitive loading and unloading of the compressorwith the degree of unloading being determined by associated sensors and controlmodule (not shown). It should be noted that in this embodiment, the compressor isshown as a high side machine and thussuction inlet 200 is directly connected to thesuction inlet ofnon-orbiting scroll 182.
Theembodiment 208 of Figure 12 represents a combination of the axialunloading arrangement of Figure 11 and the orbiting scroll biasing arrangement ofFigure 9 both described above. Accordingly, elements corresponding to likeelements shown in and described with reference to Figures 9 and 11 are indicatedby the same reference numbers. In this embodiment, the intermediate pressureaxial biasing chamber 148b for the orbiting scroll is completely separate from theunloading discharge pressure biasing chamber defined byrecess 184 andannularpiston 186.
In like manner, theembodiment 210 of Figure 13 represents acombination of the intermediate pressure biasing arrangement of Figure 8 describedabove and the axial unloading pressure biasing arrangement of Figure 11.Accordingly, corresponding elements have been indicated by the same referencenumbers used in these respective figures.
Figure 14 shows anembodiment 212 whereinshell 12 includes anupperchamber 214 at discharge pressure and alower portion 216 at a pressureintermediate suction and discharge. Accordingly,suction line 234 is directlyconnected tonon-orbiting scroll member 224. Additionally, a suitableannular seal225 may be provided betweenorbiting scroll 222 andnon-orbiting scroll 224 aroundthe outer periphery thereof. Orbitingscroll 222 is biased into sealing relationship withnon-orbiting scroll 224 by intermediate pressure inchamber 216 supplied viapassage226. In order to unloadcompressor 212, asolenoid valve 228 is provided having afirst fluid line 230 extending throughshell 12 and being connected to one end of apassage 231 provided inlower bearing housing 233. Asecond fluid line 232 isconnected between thesuction inlet 234 andsolenoid valve 228. Whensolenoidvalve 228 is opened, the intermediate pressure acting on the lower surface of orbitingscroll 222 will be vented to suction viapassage 231,fluid line 230,solenoid valve 228andfluid line 232. Becausepassage 231,fluid lines 230 and 232 andsolenoid valve228 will be sized to provide a flow volume greater than that throughpassage 226 plusthe leakage into the area defined between the bearing housing and end plate oforbitingscroll 222, the biasing force acting on orbitingscroll 222 will be relieved thusallowing the force of the fluid within the compression chamber to move orbitingscroll 222 axially away fromnon-orbiting scroll 224. As soon assolenoid valve 228 isclosed, leakage flow of intermediate pressure fluid withinlower portion 216 ofshell12 combined with flow frompassage 226 will quickly restore the biasing force onorbitingscroll 222 whereby full compression will resume. Again, as with each of theabove embodiments, cyclical actuation ofsolenoid valve 228 in response to a signalfrom a control module (not shown) resulting from appropriate sensed systemconditions will result in cyclical loading and unloading of compressor therebyenabling modulation of capacity from 100 percent down to 0 percent capacity.
Figure 15 shows anembodiment 236 which combines the features of anintermediate pressure lower shell and biasing arrangement for the orbiting scroll asshown in Figure 14 with the discharge pressure unloading arrangement of Figure 11.Accordingly, corresponding portions thereof are indicated by the same referencenumbers. Additionally, as described with reference to Figures 8, 10, and 13, aplurality ofsprings 238 are provided being positioned inrecess 240 provided inmainbearing housing 242 and acting on the lower surface of the end plate of orbitingscroll member 222. As noted above, springs 238 serve primarily to bias orbitingscroll member 222 into sealing engagement withnon-orbiting scroll member 182during initial start up and also aid in reloading ofcompressor 236. Again, full andreduced loading ofcompressor 236 will be accomplished in the same manner asdescribed above by means of cyclic actuation ofsolenoid valve 196.
Referring now to Figure 16, yet anotherembodiment 244 of the presentinvention is shown which is generally similar to that of Figure 1 and includes ashell12 having a separatingplate 246 dividing the interior thereof into adischargechamber 248 and alower chamber 250 at suction pressure. Acylindrical member252 is secured to plate 246 and defines aflow path 254 for conducting compressedfluid fromdischarge port 256 of axially movablenon-orbiting scroll 258.Non-orbiting scroll 258 has an annular recess provided in the upper surface thereof which isseparated into upper andlower chambers 260, 262 respectively by a radiallyoutwardly extendingannular flange 264 provided oncylindrical member 252. Apassage 266 placeslower chamber 262 in fluid communication with a compressionpocket at intermediate pressure to provide a biasing force for urgingnon-orbitingscroll 258 into sealing engagement with orbitingscroll 268. Anannular plate member269 is secured tonon-orbiting scroll 258, sealingly and slidingly engagestubularmember 252 and serves to close off the top ofchamber 260. A pressure responsivedischarge check valve 270 is also provided onnon-orbiting scroll 258.
A twoway solenoid valve 270 is provided being connected to dischargeconduit 272 viafluid line 274 and toupper separating chamber 260 viafluid line 276andpassage 278 intubular member 252. Avent passage 280 is provided betweennon-orbiting scroll 258 andplate 269 and extends between separatingchamber 260and thelower interior 250 ofshell 12 which is at suction pressure.Vent passage 280serves to continuously vent separatingchamber 260 to suction pressure. Whensolenoid valve 270 is in a closed position,compressor 244 will be fully loaded asshown. However, whensolenoid valve 270 is actuated to an open position by thecontrol module (not shown) in response to selected sensed conditions, separatingchamber 260 will become pressurized to substantially discharge pressure therebyovercoming the combined force of discharge pressure and suction pressure actingto biasnon-orbiting scroll member 258 toward orbitingscroll member 268. Thus,non-orbiting scroll member 258 will move axially upwardly as shown therebyunloadingcompressor 244. It should be noted that in this embodiment, the size oflines 274 and 276 andpassage 278 must be selected relative to the size ofventpassage 280 to enable build up of sufficient pressure in separatingchamber 260 toeffect unloading. Additionally, the relative size of these passages will affect the speed at whichcompressor 244 may be cycled between loaded and unloaded conditionsas well as the volume of discharge gas required to accomplish and maintainunloading.
The embodiment of Figure 17 is generally similar to that of Figure 16described above except thatspring biasing members 282 are included in theintermediate pressure chamber. Accordingly, corresponding elements are indicatedby the same reference numbers primed. As noted above, springs 280 serve primarilyto assist in biasingnon-orbiting scroll member 258 into sealing relationship withorbitingscroll member 268 during start up but will also function to assist in reloadingcompressor 244. In all other respects, the operation ofcompressor 244 will besubstantially identical to that described with reference to Figures 1 and 16 above.
Referring now to Figure 18, a further embodiment of the present inventionis shown being indicated generally at 284.Compressor 284 includes anouter shell12 having a separatingplate 286 dividing the interior thereof into adischargechamber 290 and alower chamber 292 at suction pressure. Acylindrical member294 is suitably secured to plate 286 and slidingly sealingly engages a cylindricalportion of axially movablenon-orbiting scroll member 296 so as to define a dischargefluid flow path 298 fromdischarge port 300. A pressure responsivedischarge checkvalve 302 is also provided being secured tonon-orbiting scroll 296 and operative toprevent back flow of discharge fluid fromchamber 290 into the compressionchambers.Non-orbiting scroll 296 includes a pair of annular steppedportions 304,306 on its outer periphery which cooperate withcomplementary portions 308, 310 onmain bearing housing 312 to define a generallyannular separating chamber 314.Additionally,non-orbiting scroll 296 includes a radially outwardly projectingflangeportion 316 which cooperates with a radially inwardly projectingflange portion 318 onmain bearing housing 312 to limit axially separating movement ofnon-orbitingscroll 296.
Asolenoid valve 320 is also provided being connected in fluidcommunication withchamber 314 viapassage 322 inmain bearing housing 312 andfluid line 324.Fluid lines 326 and 328 serve to interconnectsolenoid valve 320 withdischarge line 330 andsuction line 332 respectively.
Similarly to that described above, whencompressor 284 is operatingunder a normal fully loaded condition as shown,solenoid valve 320 will be in aposition to placechamber 314 in fluid communication withsuction line 332 viapassageway 322 andfluid lines 324 and 328. Under these conditions, the biasingforce resulting from discharge pressure fluid inchamber 290 acting on the uppersurface ofnon-orbiting scroll 296 withinflow path 298 will operate to urgenon-orbiting scroll 296 into sealing engagement with orbitingscroll 334. When it isdesired to unloadcompressor 284,solenoid valve 320 will operate to placechamber314 in fluid communication with discharge pressure fluid viafluid lines 326, 324 andpassageway 322. The resulting pressure inchamber 314 will then operate toovercome the biasing force being exerted onnon-orbiting scroll 296 thus causing itto move axially upwardly as shown and out of sealing engagement with orbitingscroll334 thus unloadingcompressor 284. To reloadcompressor 296,solenoid valve 320will operate to vent the discharge pressure fluid inchamber 314 tosuction line 332viapassage 322 andfluid lines 324, 328 thereby allowing the biasing force acting onnon-orbiting scroll 296 to move it axially downwardly back into sealing engagementwith orbitingscroll 334. In like manner, as noted above, operation ofsolenoid valve320 will be controlled by a suitable control module (not shown) in response to systemconditions sensed by one or more sensors to cyclically load and unloadcompressor284 as needed.
A further embodiment of the present invention is shown in Figure 19being indicated generally at 336 which is similar to the embodiment shown in Figure18. Accordingly, corresponding portions thereof have been indicated by the samereference numbers primed. In this embodiment, lower portion 292' of shell 12' is atintermediate pressure supplied viapassage 338 in orbiting scroll 334' which also actsto exert an upwardly directed biasing force thereon. Additionally,ring member 340which includes stepped portions 308', 310' is separately fabricated and secured tomain bearing housing 342.Ring member 340 also includes aportion 344 whichextends into overlying relationship with the end plate of orbiting scroll member 334'and operates to limit upward movement thereof whencompressor 336 is in anunloaded condition. Additionally, an internalflexible suction line 346 is providedbeing connected to suction line 332' and to non-orbiting scroll 296'. Acheck valve348 is provided at the connection ofline 346 with non-orbiting scroll 296' and servesto prevent back flow of fluid under compression whencompressor 336 is unloaded.Asuction control device 350 is also optionally provided in suction line 332' upstreamof the point at whichfluid line 328 is connected.Suction control device 350 will becontrolled by control module (not shown) and will operate to restrict suction gas flowthrough suction line 332' so that the reduced pressure downstream thereof will assistin evacuating chamber 314' during transition from unloaded operation to loadedoperation or also on initial start up ofcompressor 336. In all other respects theoperation including the cyclical loading and unloading ofcompressor 336 will besubstantially the same as described above.
Yet another embodiment is illustrated in Figure 20 being indicatedgenerally at 352.Compressor 352 includesnon-orbiting scroll member 354 which isaxially movably secured tomain bearing housing 356 by means of a plurality ofbushings 358 secured in position byfasteners 360.Bushings 358 andfasteners 360 cooperate to accurately and non-rotatably positionnon-orbiting scroll 354 whileallowing limited axial movement thereof. A separate annularflanged ring 362 issecured tonon-orbiting scroll 354 and cooperates with a radially outwardly disposedstationaryflanged ring member 364 to define a sealedseparating chamber 366therebetween.Ring member 364 includes apassage 368 to which one end of afluidline 370 is connected, the other end of which is connected tosolenoid valve 372.Similar to that described above,solenoid valve 372 includesfluid lines 374 and 376connected to dischargeline 378 andsuction line 380 respectively. The operation ofcompressor 352 will be substantially identical to that described above withsolenoidvalve 372 operating to cyclicallyplace chamber 366 in fluid communication withdischarge pressure fluid and suction pressure fluid to thereby cyclically load andunloadcompressor 352.
Figure 21 represents yet afurther embodiment 382 of the subjectinvention.Compressor 382 combines the separating chamber arrangement ofcompressor 352 with the suction gas supply arrangement and intermediate pressureshell ofcompressor 336 shown in Figure 19. Accordingly, corresponding portionsthereof are indicated by like numbers double primed and the operation thereof willbe substantially the same as described above.
Figure 22 shows a further modification of the present invention.Compressor 384 is substantially the same as that shown in Figure 16 with theexception thatcompressor 384 includes a twoway solenoid valve 386 connected tosuction line 388 viafluid conduit 390, a modified passage arrangement as describedbelow and omitscover member 269 definingupper chamber 260. Accordingly,portions corresponding to like portions ofcompressor 244 are indicated by likenumbers double primed. Additionally, the mounting arrangement for axially movablenon-orbiting scroll 258" is substantially identical to that described with reference to Figure 20 and hence corresponding portions thereof are indicated by like numbersprimed. In this embodiment solenoid valve is also connected tochamber 262" viafirst fluid line 392, a second internalflexible fluid line 394 and radially extendingpassage 396 provided innon-orbiting scroll 258". Additionally, a plurality ofseparatingsprings 398 are provided being positioned coaxially with bushings 358'and extending betweenmain bearing housing 400 and the lower surface ofnon-orbiting scroll 258".
Under normal fully loaded operation,non-orbiting scroll 258" will bebiased into sealing engagement with orbitingscroll 268" by the combined forceresulting from discharge pressure acting on the upper surface ofnon-orbiting scroll258" withinpassage 254" and intermediate pressure fluid withinchamber 262"conducted thereto viapassage 266". Under these conditions solenoidvalve 386 willbe in a closed position thereby preventing fluid communication betweenchamber262" andsuction line 388. When sensed system conditions indicate it is desired tounloadcompressor 384,solenoid valve 386 will open to thereby ventchamber 262"tosuction line 388 viapassage 396, andfluid lines 394, 392 and 390 thereby relievingthe intermediate biasing force onnon-orbiting scroll 258". As this biasing force isrelieved, the combined force from the fluid under compression between the scrollmembers and the force exerted bysprings 398 will operate to movenon-orbitingscroll 258" axially away from and out of sealing engagement with orbitingscroll 268"thereby unloadingcompressor 384. Of course,passageway 396,fluid lines 394, 392and 390, andsolenoid valve 386 must all be sized relative to the size ofpassage266" to ensure adequate venting ofchamber 262". Cyclical unloading and loadingofcompressor 384 will be accomplished in substantially the same manner inresponse to system conditions as described above.
The present invention is also well suited for application to dual rotatingscroll-type compressors. Such embodiments are illustrated in Figures 23 through 28.
Referring first to Figure 23, a dual rotating scroll-type compressor isshown being indicated generally at 402.Compressor 402 includes first andsecondscroll members 404, 406 rotatably supported within anouter shell 408 by upper andlower bearing members 410, 412 axially offset from each other.Upper bearingmember 410 is formed in aplate member 415 which also serves to define adischargechamber 414 into which compressed fluid exitingdischarge port 416 inupper scroll404 is directed viapassage 418. Adischarge check valve 420 is also providedoverlying discharge port 416.Lower scroll member 406 is supported within androtatable with alower housing 422. Anupper housing 424 surroundsupper scrollmember 404, is secured tolower housing 422 and cooperates withlower housing 422andupper scroll member 404 to define an intermediatepressure biasing chamber426 and a separatingchamber 428. Afluid passage 430 is provided inupper scrollmember 404 extending from a compression pocket at intermediate pressure tobiasingchamber 426 to supply fluid pressure thereto which in combination withdischarge pressure fluid acting onupper scroll member 404 withinpassage 418 willserve to biasupper scroll 404 into sealing engagement withlower scroll member 402during fully loaded operation.
Asecond passage 432 is also provided inupper scroll member 404extending from separatingchamber 428 to anannular recess 434 formed in the outerperiphery of an uppercylindrical hub portion 436 ofupper scroll 404.Annular recess434 is in fluid communication with apassage 438 provided inbearing 410 andextending radially outwardly throughplate 415.
Asolenoid valve 440 is also provided the operation of which is designedto be controlled by a control module (not shown) in response to system conditions sensed by appropriate sensors (also not shown).Solenoid valve 440 includes a firstfluid conduit 442 connected topassage 438, asecond fluid line 444 connected todischargeline 448 and athird fluid line 450 connected tosuction line 452.
Whencompressor 402 is operating under fully loaded conditions,solenoid valve 440 will be in a position to place separatingchamber 428 in fluidcommunication withsuction line 452 viapassage 432,recess 434,passage 438 andfluid lines 442 and 450. In order to unloadcompressor 402, solenoid valve willoperate to connectchamber 428 to dischargeline 448 thereby pressurizing same todischarge pressure. The force resulting from discharge pressure fluid inchamber 428will operate to movescroll member 404 axially away from and out of sealingengagement withscroll member 402 thereby unloading the compressor. Cyclicoperation of solenoid valve will result in cyclic unloading ofcompressor 402 insubstantially the same manner as discussed above.
Figure 24 illustrates another embodiment of a dual rotating scroll-typecompressor 454 in accordance with the present invention.Compressor 454 issubstantially identical in construction and operation tocompressor 402 with theexception thatcompressor 454 does not incorporate an intermediate pressure biasingchamber but rather utilizes only discharge pressure to bias the upper axially movablescroll member into sealing engagement with the lower scroll member. Accordingly,corresponding portions thereof are indicated by the same reference numbers primed.
A further embodiment of a dual rotating scroll-type compressor 456 isshown in Figure 25.Compressor 456 is substantially identical tocompressors 402and 454 with the exception that in place of the intermediate pressure biasing chamberprovided incompressor 402,compressor 456 employs a plurality ofsprings 458extending between a radially inwardly extendingportion 460 ofupper housing 424"and an upper surface ofupper scroll member 404". Accordingly, portions corresponding to like portions ofcompressor 402 are indicated by the samereference numbers double primed.Springs 458 serve to cooperate with thedischarge pressure inpassage 418" to biasupper scroll member 404" axially intosealing engagement withlower scroll member 402". In all other respects theoperation ofcompressor 456 is substantially identical to that described above.
Figure 26 shows a further embodiment of a dual rotating scroll-typecompressor 462.Compressor 462 is very similar tocompressors 402, 454, and 456except as noted below and accordingly, like portions thereof are indicated by thesame reference numbers triple primed.
Compressor 462 as shown is mounted in the bottom portion of ahermetic shell 464 and in an inverted position as compared tocompressors 402, 454and 456. Adischarge port 466 is provided inscroll member 406"' and serves todischarge compressed fluid to achamber 468 viacheck valve 470 from which it isdirected to themotor compartment 472 disposed in the upper portion ofshell 464 viaapassage 474 extending throughdrive shaft 476. A driving motor is provided inmotor compartment 472 and includes astator 478 androtor 480 secured tocrankshaft 476. Axiallymovable scroll member 404"' is rotatably supported in acylindrical bearing housing 482 formed in thelower end portion 483 ofhousing 464and cooperates therewith to define a dischargepressure biasing chamber 484. Inorder to supply discharge pressure fluid tochamber 484, apassage 486 is providedinmain bearing housing 488 which is connected to asecond passage 490 inlowerhousing portion 483.Passage 490 opens intochamber 484 and thus conducts highpressure discharge fluid frommotor compartment 472 tochamber 484 tobias scrollmember 404"' into sealing engagement withscroll member 406"' during normal fullload operation. Asecond passage 432 extends throughlower housing portion 483from recess 434'' to fluid conduit 442'''. It should be noted thatchamber 484 could alternatively be pressurized with intermediate pressure fluid by providing a passagethrough the end plate ofscroll 404"' from a compression pocket at a pressurebetween suction and discharge tochamber 484 thus eliminating the need forpassages 486 and 490. Alternatively, discharge pressure fluid could be provided tochamber 484 by means of a passage through the end plate ofscroll 404" extendingthereto from the control pocket into whichport 466 opens.
Operation ofcompressor 462 will be substantially identical to that ofcompressor 454 including the cyclical loading and unloading thereof in response toactuation ofsolenoid valve 440"' as controlled by a control module and associatedsensors (not shown).
Figure 27 is directed to another embodiment of a dual rotating scroll-typecompressor 494 in which the lower driving scroll member is axially movable.Compressor 494 includes anouter housing 496 within which upper andlower scrollmembers 498, 500 are rotatably supported. Apartition plate 502 is provided whichseparates thedischarge chamber 504 from the lowersuction pressure chamber 506and also includes acylindrical bearing portion 508 for rotatably supportingupperscroll member 498 by means ofcylindrical portion 510, the interior which also definesa dischargefluid flow path 512 fromdischarge port 514 pastdischarge check valve516 to dischargechamber 504.Upper scroll member 498 includes anannular cavity518 which opens outwardly in facing relationship tolower scroll 500. An annular ringshapedpiston member 520 is movably disposed therein and operative to exert aseparating force onlower scroll 500 in response to pressurization of the separatingchamber 522 disposed abovepiston member 520. In order to supply dischargepressure fluid tochamber 522, apassage 524 is provided inscroll member 498extending upwardly fromchamber 522 throughcylindrical portion 510 and openingradially outwardly therefrom into anannular recess 526. Asecond passage 528 extends generally radially outwardly throughplate 502 and connects tofluid line 530which in turn is connected tosolenoid valve 532.Solenoid valve 532 also has afluidline 534 extending therefrom to dischargeconduit 536 and anotherfluid line 538extending therefrom tosuction line 540.
Lower scroll member 500 is rotatably supported vialower bearing 542and includes an internally splinedcenter hub portion 544 adapted to axially movablyreceive a complementarilysplined drive shaft 546. An intermediatepressure bleedpassage 548 is formed in the end plate oflower scroll member 500 and serves toconduct biasing pressure fluid from an intermediate pressure compression pocket toa biasingchamber 550 therebelow. Aplate member 552 is secured toupper scroll498 and includes anannular recess 554 in which anannular seal 556 is disposed.Seal 556 engages the lower surface oflower scroll 500 so as to sealchamber 550from thesuction pressure chamber 506.
Under fully loaded operation,lower scroll 500 will be biased axiallyupwardly into sealing engagement withupper scroll 498 due to the force fromintermediate pressure fluid inchamber 550. Under these conditions, solenoid valvewill be in a position to placechamber 522 in fluid communication withsuction line540. When system conditions indicate a lower capacity output is desired, solenoidvalve will be actuated to a position to placechamber 522 in fluid communication withdischarge line 536 thereby pressurizingchamber 522 and effecting an axial downwardmovement ofpiston 520.Piston 520 in turn will move lower scroll 500 axiallydownwardly out of sealing engagement withupper scroll 498. When solenoid valveis cycled back to a position to ventchamber 522 tosuction line 540, the biasing forceresulting from intermediate pressure inchamber 550 will returnlower scroll member500 to sealing engagement withupper scroll member 498. The cyclic operation between loaded and unloaded operation will then be controlled in like manner similarto that described above by a control module and associated sensors.
Figure 28 shows another embodiment of a dualrotating compressor 558which is substantially the same as that described with reference to Figure 27 exceptas noted below. Accordingly, like portions thereof are indicated by the samereference numbers primed.Compressor 558 utilizes discharge pressure fluidsupplied to chamber 550' via passage 560 to bias lower scroll member 500' intosealing engagement with upper scroll member 498'. Otherwise the operation ofcompressor 558 is substantially identical to that described above.
Anothercompressor 562 incorporating a further embodiment of thepresent invention is shown in Figure 29.Compressor 562 is similar tocompressor352 shown in Figure 20 except as noted below and accordingly like portions thereofare indicated by the same reference numbers triple primed.Compressor 562incorporates apartition plate 564 which forms a part ofouter shell 566 and separatesthe interior thereof into a highpressure discharge chamber 568 and a lowpressuresuction portion 570.Partition plate 564 includes a centralcylindrical portion 572which is adapted to sealingly movably receive acylindrical portion 574 of non-orbitingaxiallymovable scroll member 354"'.Cylindrical portion 574 includes a plurality ofradial openings 576 which are aligned withopenings 578 inportion 572 to define adischargegas flow path 579 fromdischarge port 580 pastdischarge check valve 582to dischargechamber 568. Acover plate 584 is secured tocylindrical portion 574to close off the upper end ofpassage 579 and also cooperates withcylindricalportion 572 to define an intermediatepressure biasing chamber 586 therebetween.Afluid passage 588 extends from a compression pocket at intermediate pressure tochamber 586 and serves to provide fluid pressure for biasing axiallymovable scrollmember 354"' into sealing engagement with orbitingscroll 590. The operation including cyclical loading and unloading ofcompressor 562 is substantially identicalto that described with reference tocompressor 352 and the other embodimentsdescribed above.
Figure 30 illustrates acompressor 592 incorporating a furthermodification of the present invention.Compressor 592 is substantially identical tocompressor 562 of Figure 29 except as noted below and accordingly like portionsthereof are indicated by the same reference numbers quadruple primed.Compressor592 incorporates a twoway solenoid valve 594 having afluid line 596 connected tochamber 586"" and asecond fluid line 598 connected tosuction line 380"".Additionally,member 362"' and 364"' are omitted and in lieu thereof biasingsprings600 are provided being positioned in coaxial surrounding relationship tobushings358"".
Under fully loaded operating conditions, the biasing force resulting fromintermediate fluid pressure inchamber 586"" will bias axially movablenon-orbitingscroll 354"" downwardly into sealing engagement with orbitingscroll 590"" in thesame manner as discussed above and will overcome the separating force resultingfromsprings 600. When conditions indicate unloading is desired,solenoid valve 594will switch from a closed condition (which prevented venting ofchamber 586"" tosuction during fully loaded operation) to an open position thereby ventingchamber586"" tosuction line 380"" and relieving the biasing force exerted onscroll 354"".As this biasing force is relieved, the force fromsprings 600 together with the pressureof the fluid under compression will operate to move axially movable scroll member354'''' upwardly out of sealing engagement with orbiting scroll 590''''. As before,solenoid valve 594 will be operated in a cyclic manner by control means in responseto associated sensors to cyclically load and unloadcompressor 592 so as to achievethe desired degree of capacity modulation.
While the previous embodiments have been primarily directed to hermeticmotor compressors, the present invention is also well suited for use with compressorsemploying an external drive such as for example automotive air conditioning systemcompressors. The use of the present invention in such an environment can eliminatethe need for the expensive clutch systems commonly utilized in today's systems.
Figure 31 illustrates acompressor 602 which is specifically directed foruse with an external power source.Compressor 602 is similar in construction tocompressor 244 of Figure 16 except as noted below and accordingly like portionsthereof are indicated by the same reference numbers triple primed.
Compressor 602 incorporates a threeway solenoid valve 604 asopposed to the two way solenoid valve ofcompressor 244 and hence includesfluidlines 606 connected to dischargeline 272"' and asecond fluid line 608 connectedtosuction line 610. It should be noted that a two way solenoid valve could be usedin the same arrangement if desired. Becausesolenoid valve 604 is designed todirectly ventupper chamber 260"' tosuction line 610 during unloading, continuouslyopen vent passage 280 provided incompressor 244 is omitted. Driveshaft 612 ofcompressor 602 extends outwardly ofhousing 614 through suitable bearing means616 and sealing means 618 and is adapted to be connected to a suitable externalpower source such as an automobile engine via a conventional pulley and V-beltarrangement or the like.
In operation, the external power source will continuously drivedrive shaft612 thereby effecting continuous orbital movement of orbitingscroll 268"'. Whensystem conditions indicate cooling is required,solenoid valve 604 will be positionedby suitable control means to placechamber 260"' in fluid communication withsuctionline 610 thereby relieving any separating force resulting therefrom and enablingchamber 262"' which is supplied with intermediate pressure fluid viapassage 266"' to generate a biasing force which, with the biasing force resulting from dischargepressure fluid acting on the surface of non-orbiting scroll member 258''' inpassage254"', will biasnon-orbiting scroll member 258"' into sealing engagement withorbitingscroll member 268"'. When system requirements have been met,compressor 602 will be unloaded by actuation ofsolenoid valve 604 to a position inwhichchamber 260"' is placed in fluid communication withdischarge line 272"'thereby resulting in the creation of a separating force which will operate to movenon-orbiting scroll member axially out of sealing engagement with orbitingscrollmember 268"'. Cyclic control ofcompressor 602 may be achieved in the samemanner as described above thus eliminating the need for a clutch when such asystem is utilized in an automotive application.
While the previous embodiments have all been directedto the use of the fluid being compressed to effect unloadingof the respective compressors, it is also possible toaccomplish such unloading by the use of other types of forcegenerating means to effect axial movement of one or theother of the two scroll members. Such arrangements areshown and will be described with reference to Figures 32through 34.
Referring first to Figure 32, there is shown ahermetic compressor 620which includes ahousing 622 having aplate 624 operative to separate the interiorthereof into adischarge chamber 626 and alower portion 628 at suction pressure.A bearinghousing 630 is secured withinshell 622 and rotatably supports acrankshaft632 which is drivenly connected to orbitingscroll member 634. A non-orbiting axiallymovable scroll member 636 is mounted on bearinghousing 630 by means ofbushings 638 andfasteners 640 such thatscroll member 636 is slidably movablealongbushings 638 but is restrained from circumferential or radial movement.Non-orbiting scroll member 636 includes apressure biasing chamber 642 in the upper surface into which one end of ring shapedflanged member 644 projects. Theother end offlanged member 644 is secured toplate 624. Acylindrical portion 646ofnon-orbiting scroll member 636 projects upwardly through ring shapedflangedmember 644 intodischarge chamber 626 to define adischarge passage 648extending upwardly from discharge port 650 viadischarge check valve 652. Aplurality of circumferentially spacedradial openings 654 are provided adjacent theupper end ofportion 646 to placepassage 648 in fluid communication withdischargechamber 626. Acover plate 656 is secured to the upper end ofportion 646 and alsoincludesopenings 658 therein to allow passage of discharge fluid intodischargechamber 626.Non-orbiting scroll member 636 also includes apassage 660extending from a compression pocket at intermediate pressure to biasingchamber642 whereby intermediate pressure fluid may be supplied tochamber 642 to axiallybiasnon-orbiting scroll member 636 into sealing engagement with orbitingscroll 634during normal fully loaded operation. Of course, this intermediate pressure biasingforce will be aided by discharge pressure acting against the upper surfaces ofnon-orbiting scroll 636.
In this arrangement anunloading mechanism 662 is provided whichincludes a suitableforce applying actuator 664 supported on a cylindricalflangedsupport member 666 which in turn is sealingly secured to a fitting 668 provided onthe top ofshell 622. Anactuator shaft 670 extends downwardly throughmember 666and fitting 668 and has its lower end connected to coverplate 656.Actuator 664may be any suitable type force applying capable of exerting a pulling force onnon-orbiting scroll 636 such as for example an electrically actuated solenoid, apneumatic or other fluid actuated piston and cylinder device or any other type ofmechanical, magnetic, electro-mechanical, hydraulic, pneumatic, gas or spring type device. Operation of actuator will be controlled by asuitable control module 672 inresponse to sensed system conditions sensed byappropriate sensors 674.
As noted above, under fully loaded operating conditions, intermediatepressure fluid inchamber 642 will cooperate with discharge pressure fluid inpassage648 to biasnon-orbiting scroll member 636 into sealing engagement with orbitingscroll member 634. When system conditions indicate unloading is desired,controlmodule 672 will effect operation ofactuator 664 to exert a separating force onnon-orbiting scroll member 636 thereby moving it out of sealing engagement withorbiting scroll member. When fully loaded operation is to be resumed,actuator 664will be deactuated thereby enabling the biasing force fromintermediate pressurechamber 642 and discharge pressure inpassage 648 to again movenon-orbitingscroll member 636 into sealing engagement with orbitingscroll member 634.Actuator 664 will be designed to enable rapid cyclic operation so as to enablecyclical loading and unloading ofcompressor 620 in the same manner as describedabove.
Figure 33 shows a modified version of the arrangement of Figure 32wherein like portions are indicated by the same reference numbers primed. In thisembodiment, actuator 664' is located within housing 622' withactuating connections676 extending outwardly therefrom. In all other respects, compressor 620' willoperate in the same manner as that described above with reference to Figure 32.
Referring now to Figure 34, there is shown ahermetic compressor 880which combines certain features employed in the compressors of Figures 4 and 33.Compressor 880 includes anouter shell 882 having aplate 884 which separates theinterior thereof into anupper discharge chamber 886 and alower chamber 888 atsuction pressure. Amain bearing housing 890 is disposed inlower chamber 888 andserves to rotatably support adrive shaft 892 which is drivenly connected to anorbiting scroll member 894 also supported onmain bearing housing 890. Anon-orbiting scroll member 896 is axially movably secured tomain bearing housing890 and includes a cavity at the upper end thereof defined by radially inner and outercylindrical projections 898, 900 respectively. A flanged cylindrically shapedmember902 is sealingly secured toplate 884 and extends downwardly between and movablysealingly engagesprojections 898 and 900 to divide the cavity into anupperseparating chamber 904 and a lower intermediatepressure biasing chamber 906. Apassage 907 innon-orbiting scroll 896 operates to place biasingchamber 906 in fluidcommunication with a fluid pocket undergoing compression and at a pressureintermediate suction and discharge. The interior ofmember 902 cooperates withprojection 898 to define adischarge gas flowpath 908 extending fromdischarge port910 to dischargechamber 886 viadischarge check valve 912.
As best seen with reference to Figure 34A, anaxially extending bore 914is provided inmember 902 within which avalve member 916 is axially movablydisposed.Valve member 916 includes a reduceddiameter portion 918 adjacent thelower end thereof which, when valve member is in a first position, operates to placeseparatingchamber 904 in fluid communication with discharge pressure fluid inpassage 908 via radially extendingpassages 920 and 922 and when in a secondposition, to place separatingchamber 904 in fluid communication with suctionpressure fluid inarea 888 via radially extendingpassages 922 and 924. Additionally,aradial vent passage 926 extends outwardly from the bottom ofbore 914 todischargepassage 908 to facilitate movement ofvalve member 916 therein.
As shown,valve member 916 extends axially upwardly throughdischargechamber 886 and outwardly throughshell 882 and is coupled to asuitable actuator928 secured to shell 882 and which operates to move it between the first and secondpositions noted above. A fitting 930 surroundsvalve member 916 as it passes throughshell 882 and contains suitable seals to prevent fluid leakage fromdischargechamber 886.Actuator 928 may be any suitable device having the ability toreciprocatevalve member 916 between the noted first and second positionsincluding, for example, a solenoid or any other electrical, electro-mechanical,mechanical, pneumatic or hydraulically actuated device. It should also be noted thatactuator may, if desired, be mounted within the interior ofshell 882.
Under full load operation, intermediate fluid pressure in biasingchamber906 in cooperation with discharge pressure acting against the surface ofnon-orbitingscroll member 896 inpassage 908 will biasnon-orbiting scroll member 896 axiallyinto sealing engagement with orbitingscroll 894. At this time,valve member 916 willbe in a position to place separatingchamber 904 in fluid communication witharea888 at suction pressure viapassages 922 and 924. In order to unloadcompressor880,actuator 928 will operate to movevalve member 916 to a position in which itplaces separatingchamber 904 in fluid communication with discharge pressure fluidinpassage 908 viapassages 920 and 922 thereby pressurizingchamber 904. Theforce resulting from pressurization ofchamber 904 will move non-orbiting scroll outof sealing engagement with orbitingscroll member 894 to thereby unloadcompressor880. In order to reloadcompressor 880,actuator 928 operates to enablevalve 916to move back to its initial position in which the discharge pressure inchamber 904will be vented toarea 888 which is at suction pressure viapassages 922 and 924thereby enabling intermediate pressure inchamber 906 and discharge pressure fluidinpassage 908 to move non-orbiting scroll back into sealing engagement withorbitingscroll 894. Cyclical time pulsed actuation ofactuator 928 will thus enable thecapacity ofcompressor 880 to be modulated in substantially the same manner asdescribed above.
Figure 35 shows a further variation of the arrangements shown in Figures32 and 33. In this embodiment,compressor 678 includes anon-orbiting scroll 680which is fixedly mounted to bearinghousing 682 and orbitingscroll member 684 isdesigned to be axially movable.Compressor 678 includes a suitable force applyingmeans 686 in the form of an annular electro-magnetic coil secured to bearinghousing682 in a well 688 provided therein in underlying relationship to orbitingscroll member684. A suitable magneticallyresponsive member 690 is positioned within forceapplying means 686 and bears against the undersurface of orbitingscroll member684. In this embodiment, actuation of force applying means 686 operates to exert anaxially upwardly directed force on orbitingscroll member 684 thereby urging it intosealing engagement withnon-orbiting scroll member 680. Unloading ofcompressor678 is accomplished by deactuating force applying means 686 thus relieving thebiasing force generated thereby and allowing the separating force from the fluidunder compression to move orbitingscroll member 684 out of sealing engagementwith orbitingscroll member 680. Cyclic time pulsed loading and unloading may beeasily accomplished by controlling force applying means 686 in substantially thesame manner as described above.
It should be noted that whilecompressor 678 has been describedutilizing an electro-magnetic force applying means, other suitable force applyingmeans may be substituted therefor including mechanical, magnetic,electro-mechanical, hydraulic, pneumatic, gas or mechanical spring type devices.
The prior embodiments of the present invention have all been directedto various means for effecting unloading by axial separation of the respective scrollmembers. However, the present invention also contemplates accomplishingunloading by radial separation of the flank surfaces of the scroll wraps therebyproviding a leakage path between the compression pockets. Embodiments illustrating this method of unloading are shown and will be described with referenceto Figures 36 through 44.
Referring now to Figure 36, a compressor incorporating radially directedunloading is shown being indicated generally at 692.Compressor 692 is generallysimilar to the previously described compressors and includes anouter shell 694having adischarge chamber 696 andlower chamber 698 at suction pressure. Abearinghousing 700 is supported withinshell 694 and has anon-orbiting scrollmember 702 axially movably secured thereto and anorbiting scroll 704 supportedthereon which is adapted to be driven bycrankshaft 706. An intermediatepressurebiasing chamber 708 is provided at the upper end ofnon-orbiting scroll member 702which is supplied with intermediate pressure fluid from a compression pocket viapassage 710 to thereby axially bias non-orbiting scroll member into sealingengagement with orbitingscroll member 704.
Bearinghousing 700 includes a plurality of substantially identicalcircumferentially spacedchambers 712 within each of which apiston 714 is movablydisposed. Eachpiston 714 includes apin 716 projecting axially upwardly therefrom,throughopening 718 in the upper surface of bearinghousing 700 and intocorresponding axially aligned opening 720 provided innon-orbiting scroll member702. Aspring 722 is provided in each of theopenings 720 and extends between acylindrical spring retainer 724 secured tonon-orbiting scroll 702 and the upper endof each of thepins 716 and serves to exert an axially downwardly directed biasingforce thereon. As shown, each of thepins 716 includes anupper portion 726 of afirst diameter and alower portion 728 of a greater diameter.Pins 716 are positionedin surrounding relationship to the periphery of orbitingscroll 704. Anannularmanifolding assembly 729 is secured to the lower portion ofmain bearing 700 andcloses off the lower end ofrespective chambers 712.Manifolding assembly 729 includes anannular passage 731 from which respectiveaxially extending passages733 open upwardly into each of thechambers 712.
As best seen with reference to Figure 37,eccentric pin 730 ofcrankshaft706 is drivingly connected to orbiting scroll member by means of abushing 732rotatably disposed withinhub 734 provided on orbitingscroll 704.Bushing 732includes a generally oval shapedopening 736 having a flat 738 along one sidethereof which is adapted to receiveeccentric pin 730 which also includes a flat 740engageable with flat 738 through which the driving forces are transmitted to orbitingscroll 704. As shown, opening 736 is sized such that bushing and associatedorbiting scroll 704 may move relative to each other such that the orbiting radiusthrough which orbiting scroll moves may be reduced from a maximum at which theflank surfaces of the scroll wraps are in sealing engagement with each other to aminimum distance at which the flank surfaces are spaced from each other.
Compressor 692 also includes a threeway solenoid valve 742 having afluid line 744 connected toannular passage 731, asecond fluid line 746 connectedtosuction line 748 and athird fluid line 750 connected to dischargeline 752.
Under fully loaded operation,solenoid valve 742 will be in a position soas to place each of thechambers 712 in fluid communication withsuction line 748viapassages 733,passage 731, andfluid lines 744 and 746. Thus, each of thepistons and associated pins will be held in a lowered positioned bysprings 722whereby orbiting scroll member will be free to orbit at its full maximum radius. Asaxially movablenon-orbiting scroll 702 is biased into sealing engagement withorbitingscroll 704 by biasingchamber 708,compressor 692 will operate at fullcapacity. In order to unloadcompressor 692, solenoid valve will be actuated so asto placedischarge line 752 in fluid communication withannular chamber 731 whichin turn will pressurize each of thechambers 712 with discharge pressure fluid to urge each of thepistons 714 and associatedpins 716 to move axially upwardly to a fullyraised position as shown in Figure 39. Because the force of the discharge pressurefluid acting on therespective pistons 714 will not be sufficient to overcome the forcesurging the orbiting scroll radially outwardly, pins 716 will move upwardly sequentiallyas the orbiting scroll moves away therefrom. Once all of the pins have movedupwardly, thelarge diameter portion 728 ofpins 716 will be in a position to engagethearcuate cutouts 754 provided around the periphery of orbitingscroll member 704as best seen with reference to Figure 38 thereby causing the orbiting radius oforbitingscroll member 704 to be reduced to a minimum at which the flank surfacesthereof are no longer in sealing relationship and the compressor is fully unloaded.It should be noted that thepins 716 will be circumferentially spaced such that at leasttwo adjacent pins will be in engagement withcorresponding cutouts 754 throughoutthe orbit of orbitingscroll member 704. When loaded operation is to be resumed,solenoid valve will be returned to a position in whichchamber 712 is vented tosuction line 748 viapassages 733, 731 andfluid lines 744 and 746 thereby allowingsprings 722 to bias each of thepins 716 and associatedpistons 714 downwardly toa position in which reduceddiameter portion 726 of the respective pins is positionedin radially spaced relationship tocutouts 754 and orbitingscroll 704 is able to resumeits full orbital radius and full capacity compression will resume.
Figure 40 shows a modified version of the embodiment of Figures 36through 39 at 756 wherein a twoway solenoid valve 758 is utilized havingfluid lines760 and 762 connected tochamber 712 and discharge line 752' respectively. In thisembodiment, each of thechambers 712 includes apassage 764 at the lower endthereof that is in continuous communication with lower portion 698' of shell 694'which is at suction pressure. Thus, each of the chambers 712' will be continuouslyvented to suction. To unload compressor 756, solenoid valve is opened thereby placing each of the chambers 712' in fluid communication with discharge pressurefluid from discharge line 752' and biasing each of the pistons 714' into a raisedposition. The remaining portions of compressor 756 are substantially identical tothose ofcompressor 692 and accordingly are indicated by the same referencenumbers primed. Similarly, the operation of compressor 756 will in all other respectsbe substantially identical to that ofcompressor 692.
A further modification of the embodiments shown in Figures 36 through40 is shown in Figures 41 and 42 at 766. In this embodiment,cutout portions 754are deleted and twocircular openings 768 are provided in lieu thereof. Ukewise, onlytwopins 716" are provided. The diameter ofcircular openings 768 relative to thereduceddiameter portion 726" ofpins 714" will be such that there will be a slightclearance therebetween when orbitingscroll member 704" is orbiting at its maximumorbiting radius. When thelarger diameter portion 728" ofpins 716" are moved intoholes 768, the orbiting radius of orbitingscroll 704" will be reduced to a minimumthus interrupting the sealing relationship between the flank surfaces of the scrollwraps.
Additionally, in this embodiment, springs 722 have been replaced by anintermediate pressure biasing arrangement including apassage 770 inscroll member702" extending from intermediatepressure biasing chamber 708" into the upper endofmember 724". Thus, pins 716" will be biased to a lowered position by means ofintermediate fluid pressure. In all other respects the construction and operation ofcompressor 766 will be substantially identical tocompressor 692 and hencecorresponding portions have been indicated by the same reference numbers usedin Figure 35 double primed.
Another arrangement for radially unloading a scroll-type compressor isshown in Figures 43 and 44.Compressor 772 is generally similar in construction tocompressor 692 and includes anouter shell 774 having apartition plate 776 dividingthe interior thereof into anupper discharge chamber 778 and alower portion 780 atsuction pressure. A main bearing housing is secured withinlower portion 780 andincludes afirst member 782 to which axially movablenon-orbiting scroll member 784is secured by means ofbushings 786 andfasteners 788 and which also axiallysupports orbitingscroll member 790. Asecond member 792 of main bearing housingis secured to the lower end ofmember 782, rotatably supports a drivingcrankshaft794 and together withfirst portion 782 and orbitingscroll member 790 defines asubstantiallyclosed cavity 796. Orbitingscroll member 790 includes acenter hub797 having a conically shaped outer surface which is adapted to drivingly mate withaneccentric pin 798 provided oncrankshaft 794 via adrive bushing 800 disposedtherebetween.Pin 798 and drive bushing 800 are substantially identical to thatshown in Figure 37 and allow for variation in the orbiting radius of orbitingscrollmember 790 between a maximum at which the flank surfaces of the wraps are insealing engagement and a minimum at which the flank surfaces of the wraps arespaced apart.
Non-orbiting scroll member 784 includes a cavity at the upper endthereof in which a floatingseal member 802 is disposed to define an intermediatepressure biasing chamber 804 which is supplied with fluid under compression at apressure between suction and discharge viapassage 806 to thereby axially biasnon-orbiting scroll member 784 into sealing engagement with orbitingscroll member790. The upper end of floatingseal 802 sealingly engagesplate 776 and cooperateswithnon-orbiting scroll member 784 to define a dischargefluid flow path 808 fromdischarge port 810 to dischargechamber 778 viadischarge check valve 812 andopening 814 inplate 776.
Apiston member 816 is axially movably disposed withincavity 796 andincludes suitable seals to thereby define a sealedseparating chamber 818 at thelower end ofcavity 796. A plurality ofsprings 820 extend from a radially inwardlyextendingflange portion 822 ofmember 782 intosuitable wells 824 provided inpistonmember 816 and serve to biaspiston member 816 axially downwardly away fromhubportion 797. Additionally,piston member 816 includes a conically shaped radiallyinwardly facingsurface 826 at the upper end thereof which is adapted to engage andis complementary to the outer conical surface ofcenter hub 797.
As shown, a threeway solenoid valve 828 is also provided which isconnected to separatingchamber 818 viafluid line 830, tosuction line 832 viafluidline 834 and to dischargeline 836 viafluid line 838. It should be noted, however, thata two way solenoid valve connected only to suction could be substituted for threeway solenoid 828. In such a case, a bleed hole from thebottom chamber 818throughmember 792 opening intoarea 780 would be required to vent dischargepressure fluid in somewhat similar manner to that described with reference to Figure38.
Under full load operation,solenoid valve 828 will be in a position so asto place separatingchamber 818 in fluid communication withsuction line 832 viafluidlines 830 and 834 thereby maintainingchamber 818 at substantially suction pressure.The action ofsprings 820 will maintain piston member in its axially lowered positionas shown in Figure 41 at whichconical surface 826 thereof will be slightly spacedfrom the outer conical surface ofhub 796 of orbitingscroll member 790.
When unloading is desired,solenoid valve 828 will be actuated to aposition to placedischarge line 836 in fluid communication with separatingchamber818 viafluid lines 838 and 830 thereby pressurizingchamber 818 to substantiallydischarge pressure. The biasing force resulting from this pressurization ofchamber 818 will operate to movepiston 816 axially upwardly overcoming the biasing force ofsprings 820 and movingconical surface 826 into engagement with the outer conicalsurface ofhub 796 of orbitingscroll member 790. Continued upward movement ofpiston 816 to a position as shown in Figure 44 will result inconical surface 826reducing the orbiting radius of orbitingscroll member 790 such that the flank surfacesof the wraps thereof are no longer in sealing engagement with the flank surfaces ofthe non-orbiting scroll member and further compression of fluid ceases. In order toresume compression, solenoid valve is actuated to a position to ventchamber 818tosuction line 832 viafluid lines 830 and 834 thereby enablingsprings 820 tobiaspiston member 816 into its lowered position as shown in Figure 43.
It should be noted that whilecompressor 772 has been shown asincludingsprings 820 tobias piston 816 axially downwardly, it may be possible todelete these biasing members in some applications and to rely on the axialcomponent of the force exerted onpiston 818 by the engagement ofconical surface826 with the conical surface onhub 796 to cause movement of piston member awayfrom orbitingscroll member 790. Additionally,solenoid valve 828 is intended to becontrolled in a cyclical manner by means of a control module and associated sensors(not shown) in response to varying system conditions in substantially the samemanner as described above with respect to the other embodiments.
It should also be noted that the features incorporated in the variousembodiments described above should not be viewed as being restricted to use onlyin that embodiment. Rather, features of one embodiment may be incorporated intoanother embodiment in addition to or in lieu of the specific features disclosed withrespect to that other embodiment. For example, the discharge check valve providedon the outer shell of some of the embodiments may be substituted for the dischargecheck valve provided adjacent the discharge port in other embodiments or vice versa. Ukewise, the suction control module disclosed for use with the embodiment ofFigures 19 and 21 may also be incorporated into other embodiments. Further, whilein many embodiments, the solenoid valve and associated fluid lines have been shownas positioned outside of the shell, they may be located within the shell if desired.
In each of the above embodiments, it is intended that the orbiting scrollcontinue to be driven while the compressor is in an unloaded condition. Obviously,the power required to drive the orbiting scroll member when the compressor isunloaded (no compression taking place) is considerably less than that required whenthe compressor is fully loaded. Accordingly, it may be desirable to provide additionalcontrol means operative to improve motor efficiency during these periods of reducedload operation thereof.
Such an embodiment is shown schematically in Figure 45 whichcomprises amotor compressor 840 having asolenoid valve 842 connected todischargeline 844 viafluid line 846 and asuction line 848 viafluid line 850 and beingoperative to selectively place a compressor unloading mechanism in fluidcommunication with either the suction line or discharge line viafluid line 852.Solenoid valve 842 is intended to be controlled by acontrol module 854 vialine 855in response to system conditions sensed bysensors 856. As thus far described, thesystem represents a schematic illustration of any of the embodiments describedabove, it being noted thatsolenoid valve 842 could be a two way solenoid valve inlieu of the three way solenoid valve arrangement shown. In order to improveefficiency of the driving motor during reduced load operation, amotor control module858 is also provided which is connected to the compressor motor circuit via line 860and to controlmodule 854 vialine 862. It is contemplated thatmotor control module858 will operate in response to a signal fromcontrol module 854 indicating that thecompressor is being placed in an unloaded operating condition. In response to this signal, motor control module will operate to vary one or more of the compressormotor operating parameters to thereby improve its efficiency during the period ofreduced load. Such operating parameters are intended to include any variablycontrollable factors which affect motor operating efficiency including voltage reductionor varying the running capacitance of the motor for example. Oncecontrol module854 signalsmotor control module 858 that the compressor is being returned to fullyloaded operation, motor control module will then operate to restore the affectedoperating parameters to maximize motor efficiency under full load operation.
The above described compressor unloading arrangements areparticularly well suited to provide a wide range of capacity modulation in a relativelyinexpensive and effective manner and to maximize the overall efficiency of the systemas compared to prior capacity modulation arrangements. However, under someoperating conditions such as those encountered when condenser inlet pressure isat a reduced level, it may be desirable to reduce the compression ratio of thecompressor to avoid over-compression of the refrigerant at certain levels of systemcapacity reduction.
Figure 46 illustrates acompressor 864 which incorporates both theadvantages of a cyclical or pulsed unloading as described above with means forreducing the compression ratio of the compressor so as to thereby increase theability of the compressor to maximize efficiency under any operating conditions.Compressor 864 is substantially identical tocompressor 10 shown in and describedwith reference to Figure 1 except as noted below and accordingly like portionsthereof are indicated by the same reference numbers primed.
Compressor 864 includes a pair ofports 866, 868 in non-orbiting scrollmember 32' which open intocompression pockets 870, 872 respectively.Ports 866and 868 communicate with apassage 874 opening outwardly through the outer periphery of non-orbiting scroll member 32' into thelower area 876 of shell 12' whichis at suction pressure. Suitable valve means 878 are provided to selectively controlcommunication ofports 866, 868 witharea 876. Preferably,ports 866, 868 will belocated in an area such that they will begin to be in communication with therespective compression pockets prior to the compression pockets being sealed offfrom the suction fluid supply fromarea 876.
In operation, when it is determined that a reduction in compressorcapacity is desired, a determination will also be made from the system operatingconditions if the compressor is operating in an over-compression mode or anunder-compression mode. If it is determined that an over-compression mode ispresent, initial capacity reduction will most efficiently be carried out by opening valvemeans 878 which will thus placepockets 870, 872 in fluid communication witharea876 ofcompressor 864 which is at suction pressure. The effect of openingvalve 878is thus seen as reducing the operating length of the wraps as compression does notbegin until the respective pockets are closed off from the supply of suction gas. Asthe volume of the pockets when they are closed off whenports 866, 868 are opentoarea 876 is less than ifports 866, 868 were closed, the compression ratio of thecompressor is reduced. This then will eliminate or at least reduce the level ofover-compression. If additional capacity reduction is required afterports 866, 868have been opened, the cyclic pulsed unloading ofcompressor 864 may be initiatedin the same manner as described above.
If it is initially determined that the compressor is operating either in anunder-compression mode or a point between an under and over-compression mode,reducing the compression ratio thereof will only result in decreased efficiency.Therefore, under these conditions, the cyclic pulsed unloading ofcompressor 864 will be initiated in the same manner as described above while valve means 878 andhenceports 866, 868 remain in a closed position.
In this manner, the overall efficiency of the system may be maintained ata high level regardless of the operating conditions being encountered. It should benoted that while Figure 46 shows the delayed suction method of capacity modulationincorporated with the embodiment of Figure 1, it may also be utilized in conjunctionwith any of the other embodiments disclosed herein. Also, while the delayed suctionmethod of capacity modulation illustrated shows only the use of a single stepprovided by a single set of ports, it is possible to incorporate multiple steps byproviding multiple ports any number of which may be opened depending on thesystem operating conditions. Also, the specific valving and porting arrangementshown should be considered exemplary only as there exist many differentarrangements by which capacity modulation may be achieved via a delayed suctionapproach. Any number of these known delayed suction approaches may be utilizedin place of the arrangement shown. It should also be noted that the arrangement forcontrolling motor efficiency under reduced load conditions as described withreference to Figure 45 may also be incorporated into the embodiment of Figure 46.
While it will be apparent that the preferred embodiments of the inventiondisclosed are well calculated to provide the advantages and features above stated,it will be appreciated that the invention is susceptible to modification, variation andchange without departing from the proper scope or fair meaning of the subjoinedclaims.

Claims

A scroll-type compressor (692) comprising:
a first scroll member (704) having an end plate and afirst spiral wrap upstanding therefrom;
a second scroll member (702) having an end plate and asecond spiral wrap upstanding therefrom, said first and secondscroll members being positioned with said first and secondspiral wraps interleaved with each other;
a fixed support structure (700) for supporting said firstand second scroll members for relative orbital movementtherebetween whereby said first and second spiral wraps definesealed moving fluid pockets which progressively decrease in sizeas they move from a radially outer position to a radially innerposition to provide a source (696, 752) of pressurized fluid;
a power source (706) coupled to said first scroll memberand operative to effect said relative orbital movement betweensaid first (704) and second (702) scroll members; and
a device including a force applying structure (714) toeffect relative movement between said first (704) and second(702) scrolls to thereby form a leakage path between said movingfluid pockets while said power source (706) continues to operatewhereby the capacity of said compressor is reduced;
characterized in that:
said device includes a passage (742, 744, 746, 750) forsupplying pressurized fluid from said source (752) ofpressurized fluid to cause said force applying structure (714)to selectively apply a force to cyclically effect the relative movementbetween said first (704) and second (702) scrolls;
a valve (742) for opening and closing said passage; anda control module operative to control operation of said valveand said force applying structure in response to sensed operatingconditions.
A scroll-type compressor as set forth in claim 1,wherein said leakage path is sufficient to reduce the capacityof said scroll-type compressor (692) to substantially zero.
A scroll-type compressor as set forth in claim 1 orclaim 2, wherein said device (714) operates to reduce the radiusof said relative orbital movement.
A scroll-type compressor as set forth in any one of the preceding claims, wherein said device (714) is actuated in atime pulsed manner between a first position in which saidleakage path is formed for a first predetermined time period anda second position in which said moving fluid pockets are sealedfrom each other for a second predetermined time period.
A scroll-type compressor as set forth in claim 4,further comprising a sensor (82) connected to a control module(80) and operative to provide a signal thereto indicative ofoperating conditions, said control module (80) being connectedto said device and operative to control the duration of saidfirst and second predetermined time periods to thereby modulatethe capacity of said compressor while maximizing the efficiencythereof for said operating conditions.
A scroll-type compressor as set forth in any one ofthe preceding claims, wherein said device includes a chamber(712) and, a piston (714) movably disposed within said chamber,said piston (714) being movable into engagement with said firstscroll member (704) to reduce the orbital radius thereof.
A scroll-type compressor as set forth in claim 7,wherein said passage (744) supplies pressurized fluid to saidchamber (712) to effect movement of said piston (714).
A scroll-type compressor as set forth in claim 6,wherein a valve (742) is operative to connect said chamber (712)to an area at substantially suction pressure to thereby ventsaid chamber (712) and allow movement of said piston out ofengagement with said first scroll member (704).
A scroll-type compressor as set forth in any one ofthe preceding claims, further comprising a motor (14, 16)drivingly connected to said first scroll member (704) and amotor controller operative to vary an operating parameter ofsaid motor in response to a signal from said device indicativeof actuation thereof to thereby improve the efficiency of saidmotor while the capacity of said machine is reduced.
A scroll type compressor as set forth in claim 6wherein said piston (714) is movable between a first position inwhich the radius of said relative orbital movement has a first magnitude and a second position in which said piston operates torestrict the radius of said relative orbital movement to amagnitude less than said first magnitude to thereby form aleakage path between said moving fluid pockets whereby thecapacity of said compressor is reduced.
A scroll-type compressor as set forth in claim 10,wherein said piston (714) is cycled between said first andsecond positions in a time pulsed manner whereby said piston isin said first position for a first predetermined time period andin said second position for a second predetermined time period.
A scroll-type compressor as set forth in claim 10or claim 11, further comprising a sensor (82) connected to acontrol module (80) and operative to provide a signal theretoindicative of operating conditions, said control module beingoperative to control movement of said piston between said firstand second positions and to control the duration of said firstand second predetermined time periods.
A scroll-type compressor as set forth in any one ofclaims 10 to 11, wherein said piston (714) is movable into andout of engagement with a surface of said first scroll member.
A scroll-type compressor as set forth in claim 13,wherein said surface is conical and is formed on a projectionprovided on the end plate of said first scroll member.
A scroll-type compressor as set forth in claim 13,further comprising a passage (744) for supplying pressurizedfluid to said chamber to move said piston from said firstposition to said second position and a valve to control flow ofsaid pressurized fluid to said chamber.
A scroll-type compressor as set forth in claim 13,wherein said surface is provided on the periphery of said firstend plate.
A scroll-type compressor as set forth in claim 13,wherein said surface is in the form of an opening in said firstend plate.