US20070036661A1 - Capacity modulated scroll compressor - Google Patents

Abstract

A scroll compressor has a biasing chamber which contains a pressurized fluid. The pressurized fluid within the chamber biases the two scroll members together. A rotatable ring is attached to one of the scroll members to open and close a passage leading to this biasing chamber. When the ring opens the passage in one embodiment, this releases the pressurized fluid to remove the load, biasing the two scroll members together. When the biasing load is removed, the two scroll members separate, creating a leakage path between discharge and suction to reduce the capacity of the scroll compressor. When the ring opens the passage in another embodiment, a delayed suction passage is opened to reduce the capacity of the compressor.

Description

FIELD OF THE INVENTION
• The present invention relates to capacity modulation of compressors. More particularly, the present invention relates to the capacity modulation of a scroll compressor by controlling the fluid pressure in a chamber where the fluid pressure in the chamber biases the two scrolls together.
BACKGROUND AND SUMMARY OF THE INVENTION
• Capacity modulation is often a desirable feature to incorporate into the compressors of air conditioning and refrigeration systems in order to better accommodate the wide range of loading to which the systems may be subjected. Many different approaches have been utilized for providing this capacity modulation feature. These approaches have ranged from control of the suction inlet of the compressor to bypassing compressed discharge gas back into the suction pressure zone of the compressor. With a scroll-type compressor, capacity modulation has often been accomplished by using a delayed suction approach which comprises providing ports at various positions extending through one of the base plates which, when opened, allow the initially formed compression chambers between the intermeshing scroll wraps to communicate with the suction zone of the compressor. This delays the point at which the sealed compression chambers are formed and, thus, delays the start of compression of the suction gas. This method of capacity modulation has the effect of actually reducing the compression ratio of the compressor. While these delayed suction systems are effective at reducing the capacity of the compressor, they are only able to provide a predetermined amount of compressor unloading with the amount being determined by the position of the unloading ports along the end plate. While it is possible to provide multiple step unloading by incorporating a plurality of unloading ports at different locations, this approach becomes costly and it requires additional space to accommodate the separate controls for opening and closing each set of ports. Even when using multiple unloading ports, it is typically not possible to control the capacity of the compressor between 0% and 100% using this delayed suction technique.
• More recently, compressor unloading and, thus, capacity modulation has been accomplished by cyclically effecting axial or radial separation of the two scroll members for predetermined periods of time during the operating cycle of the compressor. In order to facilitate the axial unloading or axial separation of the two scroll members, a biasing chamber is formed in or adjacent one of the two scroll members; and this biasing chamber is placed in communication with a source of compressed fluid in a pressure chamber or the discharge chamber of the compressor. The fluid in the biasing chamber is cyclically released to the suction area of the compressor to facilitate the unloading of the compressor.
• The continued development of capacity modulated scroll compressors has been directed towards the simplification of the capacity modulation devices in order to lower the costs of the capacity modulated systems, as well as simplifying the overall manufacture, design and development of these capacity modulated systems without sacrificing performance and more preferably increasing the performance and/or reliability of the capacity modulation system.
• The present invention provides the art with a capacity modulated compressor which vents an existing intermediate pressurized chamber cyclically to suction to modulate the capacity of the compressor. The existing intermediate pressurized chamber is utilized in the compressor to bias the two scrolls together as well as to bias a floating seal into contact with a partition or the shell to seal a leakage passage between discharge pressure and the suction pressure zone of the compressor. A sealing system is incorporated into the scroll member defining the intermediate pressurized chamber. The sealing system incorporates a lip seal which improves both the performance and the reliability of the capacity modulation system.
• Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
• In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:
• FIG. 1 is a vertical section view of a scroll-type compressor incorporating a capacity modulation system in accordance with the present invention;
• FIG. 2 is a fragmentary view of the compressor ofFIG. 1 showing the capacity modulation system shown inFIG. 1:
• FIG. 3 is a plan view of the compressor shown inFIG. 1 with the top portion of the outer shell removed;
• FIG. 4 is an enlarged view showing a portion of a modified valving ring;
• FIG. 5 is a perspective view of the valving ring incorporated in the compressor ofFIG. 1;
• FIG. 6 is a fragmentary section view showing the scroll assembly forming a part of the compressor ofFIG. 1;
• FIG. 7 is an enlarged detailed view of the actuating assembly incorporated in the compressor ofFIG. 1;
• FIG. 8 is a perspective view of the compressor ofFIG. 1 with portions of the outer shell broken away;
• FIG. 9 is a fragmentary section view of the compressor ofFIG. 1 showing the pressurized fluid supply passages provided in the non-orbiting scroll;
• FIG. 10 is an enlarged section view of the solenoid valve assembly incorporated in the compressor ofFIG. 1;
• FIG. 11 is an enlarged view of the sealing system shown inFIG. 1 with the by-pass port closed;
• FIG. 12 is an enlarged view of the sealing system shown inFIG. 1 with the by-pass port open;
• FIG. 13 is a fragmentary view of a compressor incorporating a capacity modulation system in accordance with another embodiment of the present invention; and
• FIG. 14 is a fragmentary section view showing the scroll assembly forming a part of the compressor ofFIG. 13.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
• While the present invention is suitable for incorporation in many different types of scroll machines, including hermetic machines, open drive machines and non-hermetic machines, for exemplary purposes it will be described herein incorporated in a hermetic scroll refrigerant motor-compressor10 of the “low side” type (i.e., where the motor and compressor are cooled by suction gas in the hermetical shell, as illustrated in the vertical section shown inFIG. 1). Generally speaking,compressor10 comprises a cylindricalhermetic shell12 which includes at the upper end thereof anend cap14.End cap14 is provided with a refrigerant discharge fitting16 optionally having the usual discharge valve therein. Other elements affixed to the shell include a transversely extendingpartition18 which is welded about its periphery at the same point thatend cap14 is welded toshell12, a two-piece main bearing housing20 which is affixed toshell12 at a plurality of points in any desirable manner, and a suction gas inlet fitting22 disposed in communication with the suction pressure zone ofcompressor10 insideshell12.
• Amotor stator24 is press fit into aframe26 which is in turn press fit intoshell12. Acrankshaft28 having aneccentric crank pin30 at the upper end thereof is rotatably journaled in abearing32 in main bearing housing20 and a second bearing34 inframe26.Crankshaft28 has at the lower end the usual relatively large diameter oil-pumpingconcentric bore36 which communicates with a radially outwardly inclinedsmaller diameter bore38 extending upwardly therefrom to the top ofcrankshaft28. The lower portion of theinterior shell12 is filled with lubricating oil in the usual manner andconcentric bore36 at the bottom ofcrankshaft28 is the primary pump acting in conjunction withbore38, which acts as a secondary pump, to pump lubricating fluid to all the various portions ofcompressor10 which require lubrication.
• Crankshaft28 is rotatively driven by an electricmotor including stator24 havingwindings40 passing therethrough, and arotor42 press fit oncrankshaft28 and having one ormore counterweights44. Amotor protector46, of the usual type, is provided in close proximity tomotor windings40 so that if the motor exceeds its normal temperaturerange motor protector46 will de-energize the motor.
• The upper surface of main bearing housing20 is provided with an annular flat thrust bearing surface48 on which is disposed an orbitingscroll member50 comprising anend plate52 having the usual spiral vane orwrap54 on the upper surface thereof, an annularflat thrust surface56 on the lower surface, and projecting downwardly therefrom acylindrical hub58 having a journal bearing60 therein and in which is rotatively disposed a drive bushing62 having an inner bore in whichcrank pin30 is drivingly disposed.Crank pin30 has a flat on one surface (not shown) which drivingly engages a flat surface in a portion of the inner bore of drive bushing62 to provide a radially compliant driving arrangement, such as shown in assignee's U.S. Pat. No. 4,877,382, the disclosure of which is herein incorporated by reference.
• Wrap54 meshes with a non-orbiting spiral wrap64 forming a part of anon-orbiting scroll member66 which is mounted to main bearing housing20 in any desired manner which will provide limited axial movement ofnon-orbiting scroll member66. The specific manner of such mounting is not relevant to the present inventions. For a more detailed description of the non-orbiting scroll suspension system, see assignee's U.S. Pat. No. 5,055,010, the disclosure of which is hereby incorporated herein by reference.
• Non-orbiting scroll member66 has a centrally disposed discharge passageway communicating with an upwardlyopen recess72 which is in fluid communication via anopening74 inpartition18 with a discharge muffler chamber76 defined byend cap14 andpartition18. A pressure relief valve is disposed between the discharge muffler chamber76 and the interior ofshell12. The pressure relief valve will open at a specified differential pressure between the discharge and suction pressures to vent pressurized gas from the discharge muffler chamber76.Non-orbiting scroll member66 has in the upper surface thereof anannular recess80 having parallel coaxial side walls in which is sealingly disposed for relative axial movement an annular floatingseal82 which serves to isolate the bottom ofrecess80 from the presence of gas under suction and discharge pressure so that it can be placed in fluid communication with a source of intermediate fluid pressure by means of one ormore passageways84. Non-orbitingscroll member66 is thus axially biased against orbitingscroll member50 by the forces created by discharge pressure acting on the central portion ofnon-orbiting scroll member66 and those created by intermediate fluid pressure acting on the bottom ofrecess80. This axial pressure biasing, as well as various techniques for supportingnon-orbiting scroll member66 for limited axial movement, are disclosed in much greater detail in assignee's aforesaid U.S. Pat. No. 4,877,328.
• Relative rotation of the scroll members is prevented by the usual Oldham coupling comprising aring86 having a first pair of keys88 (one of which is shown) slidably disposed in diametrically opposed slots90 (one of which is shown) innon-orbiting scroll member66 and a second pair of keys (not shown) slidably disposed in diametrically opposed slots in orbitingscroll member50.
• Referring now toFIG. 2. Although the details of construction of floatingseal82 are not part of the present invention, for exemplarypurposes floating seal82 is of a coaxial sandwiched construction and comprises anannular base plate100 having a plurality of equally spaced upstandingintegral projections102. Disposed onplate100 is anannular gasket106 having a plurality of equally spaced holes which receiveprojections102. On top ofgasket106 is disposed anupper seal plate110 having a plurality of equally spaced holes which receiveprojections102.Seal plate110 has disposed about the inner periphery thereof an upwardly projectingplanar sealing lip116. The assembly is secured together by swaging the ends of each of theprojections102, as indicated at118.
• The overall seal assembly therefore provides three distinct seals; namely, an inside diameter seal at124, an outside diameter seal at128 and a top seal at130.Seal124 is between the inner periphery ofgasket106 and the inside wall ofrecess80.Seal124 isolates fluid under intermediate pressure in the bottom ofrecess80 from fluid under discharge pressure inopen recess72.Seal128 is between the outer periphery ofgasket106 and the outer wall ofrecess80, and isolates fluid under intermediate pressure in the bottom ofrecess80 from fluid at suction pressure withinshell12.Seal130 is between sealinglip116 and an annular wearring surrounding opening74 inpartition18, and isolates fluid at suction pressure from fluid at discharge pressure across the top of the seal assembly. The details of the construction of floatingseal82 is similar to that described in U.S. Pat. No. 5,156,539, the disclosure of which is hereby incorporated herein by reference.
• The compressor is preferably the “low side” type in which suction gas entering gas inlet fitting22 is allowed, in part, to escape intoshell12 and assist in cooling the motor. So long as there is an adequate flow of returning suction gas the motor will remain within desired temperature limits. When this flow drops significantly, however, the loss of cooling will eventually causemotor protector46 to trip and shut the machine down.
• As thus far described,scroll compressor10 is typical of such scroll-type refrigeration compressors. In operation, suction gas directed to the lower chamber via suction gas inlet fitting22 is drawn into the moving fluid pockets as orbitingscroll member50 orbits with respect tonon-orbiting scroll member66. As the moving fluid pockets move inwardly, this suction gas is compressed and subsequently discharged into discharge muffler chamber76 via upwardlyopen recess72 innon-orbiting scroll member66 and discharge opening74 inpartition18. Compressed refrigerant is then supplied to the refrigeration system via discharge fitting16.
• In selecting a refrigeration compressor for a particular application, one would normally choose a compressor having sufficient capacity to provide adequate refrigerant flow for the most adverse operating conditions to be anticipated for that application and may select a slightly larger capacity to provide an extra margin of safety. However, such “worst case” adverse conditions are rarely encountered during actual operation and thus this excess capacity of the compressor results in operation of the compressor under lightly loaded conditions for a high percentage of its operating time. Such operation results in reducing overall operating efficiency of the system. Accordingly, in order to improve the overall operating efficiency under generally encountered operating conditions while still enabling the refrigeration compressor to accommodate the “worse case” operating conditions,compressor10 is provided with a capacity modulation system. The capacity modulation system allows the compressor to operate at the capacity required to meet the requirements of the system.
• The capacity modulation system includes anannular valving ring150 movably mounted onnon-orbiting scroll member66, anactuating assembly152 supported withinshell12 and acontrol system154 for controlling operation of the actuating assembly.
• As best seen with reference toFIGS. 2 and 5,valving ring150 comprises a generally circular shapedmain body156 having a pair ofholes158 and160 extending therethrough. A pair of T-shapedslots162 are formed into the inside diameter ofmain body156. T-shapedslots162 include anaxial portion164 and acircumferential portion166. T-shapedslots162 each accept a pin (not shown) extending from anouter surface168 ofnon-orbiting scroll member66.Axial portion164 allows for the assembly ofvalving ring150 over the pins and ontonon-orbiting scroll member66.Circumferential portion166 restrict the rotational movement ofvalving ring150 with respect tonon-orbiting scroll member66. Aflange170 extend radially outward frommain body156 to support apin172 which is utilized to rotatevalving ring150 with respect tonon-orbiting scroll member66 as detailed below.
• Non-orbiting scroll member66 also includes a pair of diametrically opposedradial passages192 and194 opening to theouter surface168 ofnon-orbiting scroll member66.Passages192 and194 extend radially inwardly through the end plate ofnon-orbiting scroll member66. Oneaxially extending passage84 places the inner end ofpassage192 in fluid communication withannular recess80 while anotheraxially extending passage84 places the inner end ofpassage194 in fluid communication withannular recess80.
• As best seen with reference toFIG. 7, actuatingassembly152 includes a piston andcylinder assembly200 and areturn spring assembly202. Piston andcylinder assembly200 includes ahousing204 having a bore defining acylinder206 extending inwardly from one end thereof and within which apiston208 is movably disposed. Anouter end210 ofpiston208 projects axially outwardly from one end ofhousing204 and includes an elongated or oval-shapedopening212 therein adapted to receivepin172 forming a part ofvalving ring150. Elongated oroval opening212 is designed to accommodate the arcuate movement ofpin172 relative to the linear movement ofpiston end210 during operation. A dependingportion214 ofhousing204 has secured thereto a suitably sized mountingflange216 which is adapted to enablehousing204 to be secured to asuitable flange member218 bybolts220.Flange218 is in turn suitably supported withinouter shell12 such as by main bearing housing20.
• Apassage222 is provided in dependingportion214 extending upwardly from the lower end thereof and opening into a laterally extendingpassage224 which in turn opens into the inner end ofcylinder206. A second laterally extendingpassage226 provided in dependingportion214 opens outwardly through the sidewall thereof and communicates at its inner end withpassage222. A second relatively small laterally extendingpassage228 extends fromfluid passage222 in the opposite direction offluid passage224 and opens outwardly through anend wall230 ofhousing204.
• Apin member232 is provided upstanding fromhousing204 to which is connected one end of areturn spring234 the other end of which is connected to an extended portion ofpin172.Return spring234 will be of such a length and strength as to urgevalving ring150 andpiston208 into the position shown inFIG. 7 whencylinder206 is fully vented viapassage228.
• As best seen with reference toFIGS. 1, 8 and10,control system154 includes avalve body236 having a radially outwardly extendingflange238 including aconical surface240 on one side thereof.Valve body236 is inserted into anopening242 inouter shell12 and positioned withconical surface240 abutting the peripheral edge ofopening242 and then welded to shell12 with acylindrical portion244 projecting outwardly therefrom.Cylindrical portion244 ofvalve body236 includes an enlarged diameter threaded bore246 extending axially inwardly and opening into a recessedarea248.
• Valve body236 includes ahousing250 having afirst passage252 extending downwardly from a substantially flatupper surface254 and intersecting a second laterally extendingpassage256 which opens outwardly into the area of opening242 inshell12. Athird passage258 also extends downwardly fromsurface254 and intersects a fourth laterally extendingpassage260 which also opens outwardly into recessedarea248 provided in the end portion ofvalve body236.
• A manifold262 is sealingly secured to surface254 by means of suitable fasteners and includes fittings for connection of one end of each offluid lines264 and266 so as to place them in sealed fluid communication withrespective passages258 and252.
• Asolenoid coil assembly268 is designed to be sealingly secured tovalve body236 and includes anelongated tubular member270 having a threaded fitting272 sealingly secured to the open end thereof. Threaded fitting272 is adapted to be threadedly received withinbore246 and sealed thereto by means of an O-ring274. Aplunger276 is movably disposed withintubular member270 and is biased outwardly therefrom by aspring278 which bears against a closed end oftubular member270. Avalve member280 is provided on the outer end ofplunger276 and cooperates with avalve seat282 to selectively close offpassage256. Asolenoid coil284 is positioned ontubular member270 and secured thereto by means of a nut threaded on the outer end oftubular member270.
• In order to supply pressurized fluid to actuatingassembly152, anaxially extending passage286 extends downwardly fromopen recess72 and connects to a generally radially extendingpassage288 innon-orbiting scroll member66.Passage288 extends radially and opens outwardly through the circumferential sidewall ofnon-orbiting scroll member66 as best seen with reference toFIG. 11. The other end offluid line264 is sealingly connected tothird passage258 whereby a supply of compressed fluid at discharge pressure may be supplied fromopen recess72 tovalve body236. A circumferentially elongatedslot290 is provided invalving ring150 suitably positioned so as to enablefluid line264 to pass therethrough while accommodating the rotational movement ofvalving ring150 with respect tonon-orbiting scroll member66.
• In order to supply pressurized fluid fromvalve body236 to actuating piston andcylinder assembly200,fluid line266 extends fromvalve body236 and is connected topassage226 provided in dependingportion214 of housing204 (FIG. 7).
• Valving ring150 may be easily assembled tonon-orbiting scroll member66 by merely aligningaxial portions164 of T-shapedslots162 with the respective pins extending fromouter surface168 ofnon-orbiting scroll member66. Thereafter valvingring150 is rotated into the desired position withcircumferential portions166 of T-shapedslots162 cooperating with the respective pins extending fromouter surface168 to control the rotation ofvalving ring150 with respect tonon-orbiting scroll member66. Thereafter,cylinder assembly200 of actuatingassembly152 may be positioned on mountingflange218 withpiston end210 receivingpin172. One end ofspring234 may then be connected to pinmember232. Thereafter, the other end ofspring234 may be connected to pin172 thus completing the assembly process.
• Whilenon-orbiting scroll member66 is typically secured to main bearing housing20 bysuitable bolts292 prior to assembly ofvalving ring150, it may in some cases be preferable to assemble this continuous capacity modulation component tonon-orbiting scroll member66 prior to assembly ofnon-orbiting scroll member66 to main bearing housing20. This may be easily accomplished by merely providing a plurality of suitably positionedarcuate cutouts294 along the periphery ofvalving ring150 as shown inFIGS. 4 and 5. These cutouts will afford access to securingbolts292 withvalving ring150 assembled tonon-orbiting scroll member66.
• In operation, when system operating conditions as sensed by one ormore sensors296 indicate that full capacity ofcompressor10 is required,control module298 will operate in response to a signal fromsensors296 to energizesolenoid coil284 ofsolenoid coil assembly268 thereby causingplunger276 to be moved out of engagement withvalve seat282 thereby placingpassages256 and260 in fluid communication. Pressurized fluid at substantially discharge pressure will then be allowed to flow fromopen recess72 tocylinder206 viapassages286,288fluid line264,passages258,260,256,252fluid line266 andpassages226,222 and224. This fluid pressure will then causepiston208 to move outwardly with respect tocylinder206 thereby rotatingvalving ring150 so as to movemain body156 into sealing overlying relationship topassages192 and194 as illustrated inFIG. 11. This will then prevent intermediate pressurized gas disposed withinrecess80 from being exhausted or vented throughpassages192 and194.Compressor10 will then operate at its full capacity.
• When the load conditions change to the point that the full capacity ofcompressor10 is not required,sensors296 will provide a signal indicate thereof tocontroller298 which in turn will deenergizesolenoid coil284 ofsolenoid coil assembly268.Plunger276 will then move outwardly fromtubular member270 under the biasing action ofspring278 thereby movingvalve member280 into sealing engagement withseat282 thus closing offpassage256 and the flow of pressurized fluid therethrough. It is noted that recessedarea248 will be in continuous fluid communication withopen recess72 and hence continuously subject to discharge pressure. This discharge pressure will aid in biasingvalve member280 into fluid tight sealing engagement withvalve seat282 as well as retaining same in such relationship.
• The pressurized gas contained incylinder206 will bleed back into the suction zone ofcompressor10 viavent passage228 thereby enablingspring234 to rotatevalving ring150 back to a position in whichpassages192 and194 are aligned withholes158 and160 ofvalving ring150 as illustrated inFIG. 12.Spring234 will also movepiston208 inwardly with respect tocylinder206. In this position, the intermediate pressure withinannular recess80 will be exhausted or vented throughpassages192 and194 andholes158 and160. The venting of the intermediate pressurized fluid removes the biasing force urgingnon-orbiting scroll member66 into sealing engagement with orbitingscroll member50 to create a leak between the discharge pressure zone and the suction pressure zone. This leak causes the capacity ofcompressor10 to move to zero capacity. A spring urges floatingseal82 upwards and maintains the sealing relationship attop seal130. Thus, by controllingsolenoid coil assembly268 in a pulsed width modulation mode, the capacity ofcompressor10 can be set anywhere between zero capacity and full capacity.
• It should be noted that the speed with whichvalving ring150 may be moved between the modulated position and the unmodulated position will be directly related to the relative size ofvent passage228 and the supply lines. In other words, becausepassage228 is continuously open to the suction pressure zone ofcompressor10, whensolenoid coil284 ofsolenoid coil assembly268 is energized a portion of the pressurized fluid flowing fromopen recess72 will be continuously vented to suction pressure. The volume of this fluid will be controlled by the relative sizing ofpassage228. However, aspassage228 is reduced in size, the time required to ventcylinder206 will increase thus increasing the time required to switch from reduced capacity to full capacity.
• While actuatingassembly152 has been illustrated including piston andcylinder assembly200 and returnspring assembly202, it is within the scope of the present invention to utilize a solenoid valve assembly attached directly to pin172 as actuatingassembly152 and controlling the solenoid valve assembly using PWM (pulse width modulation) or by using direct control to effect the rotation ofvalving ring150 if desired.
• Efficient operation of the capacity modulation system of the present invention requires the proper sealing betweenmain body156 ofvalving ring150 andpassages192 and194 extending intonon-orbiting scroll member66.
• As best illustrated inFIGS. 11 and 12,non-orbiting scroll member66 defines acounterbore300 located at the outer end ofpassages192 and194. Disposed within eachcounterbore300 is anannular lip seal302. When valvingring150 is rotated such thatmain body156 closespassages192 and194 as illustrated inFIG. 11,lip seal302 has acylindrical portion304 having a first lip seal that seals againstcounterbore300 andannular portion306 that has a second lip seal that seals againstmain body156 ofvalving ring150.Lip seal302 is a self-actuating seal. Intermediate pressurized fluid withinpassages192 and194 will urgecylindrical portion304 oflip seal302 into sealing engagement withcounterbore300. Also, the intermediate pressurized fluid withinpassages192 and194 will urgeannular portion306 into sealing engagement withmain body156 ofvalving ring150.
• As illustrated inFIG. 12, when valvingring150 is rotated to a position where holes158 and160 are aligned withpassages192 and194, respectively, intermediate pressurized fluid inpassages192 and194 andannular recess80 will be vented to the suction pressure zone ofcompressor10. The diameter ofholes158 and160 are sized to be the same as the internal diameter formed byannular portion306 oflip seal302. Thus,annular portion306 never completely loses contact withmain body156 ofvalving ring150.Main body156 ofvalving ring150 retainslip seal302 withincounterbore300 due to this continued contact.
• Referring now toFIGS. 13 and 14, a capacity modulation system in accordance with the present invention is illustrated. The capacity modulation system described above has the capability to modulate the capacity ofcompressor10 between zero capacity and full capacity. The capacity control system illustrated inFIGS. 13 and 14 has the ability to modulate the capacity ofcompressor10 between full capacity and a selected reduced capacity.
• FIGS. 13 and 14 illustratenon-orbiting scroll member66′ which is the same asnon-orbiting scroll member66 except that the one ormore passageways84 which extend from a source of intermediate fluid pressure to recess80 are no longer in communication withradial passages192 and194. Thus,recess80 is continuously supplied with intermediate pressurized fluid frompassageway84.
• Non-orbiting scroll member66′ defines a firstaxially extending passage196 and a secondaxially extending passageway198.Axially extending passage196 extends between an intermediate pressurized moving pocket defined by scroll wraps54 and64 andradial passage192. Axial extendingpassage198 extends between an intermediate pressurized moving pocket defined by scroll wraps54 and64 andradial passage194. Preferablypassages196 and198 will be oval in shape so as to maximize the size of the opening thereof without having a width greater than the width ofwrap54 of orbitingscroll member50.
• In operation, when system operating conditions as sensed by one ormore sensors296 indicate that full capacity ofcompressor10 is required,control module298 will operate in response to a signal fromsensors296 to energizesolenoid coil284 ofsolenoid coil assembly268 thereby causingplunger276 to be moved out of engagement withvalve seat282 thereby placingpassages256 and260 in fluid communication. Pressurized fluid at substantially discharge pressure will then be allowed to flow fromopen recess72 tocylinder206 viapassages286,288fluid line264,passages258,260,256,252fluid line266 andpassages226,222 and224. This fluid pressure will then causepiston208 to move outwardly with respect tocylinder206 thereby rotatingvalving ring150 so as to movemain body156 into sealing overlying relationship topassages192 and194 as illustrated inFIG. 11. This will then prevent intermediate pressurized gas disposed within the moving pockets defined by scroll wraps54 and64 from being exhausted or vented throughpassages192,194,196 and198.Compressor10 will then operate at its full capacity.
• When the load conditions change to the point that the full capacity ofcompressor10 is not required,sensors296 will provide a signal indicate thereof tocontroller298 which in turn will deenergizesolenoid coil284 ofsolenoid coil assembly268.Plunger276 will then move outwardly fromtubular member270 under the biasing action ofspring278 thereby movingvalve member280 into sealing engagement withseat282 thus closing offpassage256 and the flow of pressurized fluid therethrough. It is noted that recessedarea248 will be in continuous fluid communication withopen recess72 and hence continuously subject to discharge pressure. This discharge pressure will aid in biasingvalve member280 into fluid tight sealing engagement withvalve seat282 as well as retaining same in such relationship.
• The pressurized gas contained incylinder206 will bleed back into the suction zone ofcompressor10 viavent passage228 thereby enablingspring234 to rotatevalving ring150 back to a position in whichpassages192 and194 are aligned withholes158 and160 ofvalving ring150 as illustrated inFIG. 12.Spring234 will also movepiston208 inwardly with respect tocylinder206. In this position, the moving pockets defined by scroll wraps54 and64 will be exhausted or vented throughpassages192,194,196 and198 andholes158 and160. The venting of the moving pockets reduces the capacity ofcompressor10 by delaying the point at which compression begins by delaying the point at which the sealed chambers are formed. This has the effect of reducing the compression ratio of the compressor by a predetermined amount. The predetermined amount of the reduction of the compression ratio of the compressor can be controlled by the location ofaxial passages196 and198.
• Passages196 and198 may be located so that they are in communication with the respective suction pockets at any point up to 360° inwardly from the point at which the trailing flank surfaces move into sealing engagement. If they are located further inwardly than this, compression of the fluid in the pockets will have begun and hence venting thereof will result in lost work and a reduction in efficiency.
• The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

Claims (35)

1. A scroll machine comprising:

a first scroll member having a first spiral wrap projecting outwardly from a first end plate, said first scroll member defining a recess and a fluid passage extending from said recess to an outer surface of said first scroll member;

a second scroll member having a second spiral scroll wrap projecting outwardly from a second end plate, said second spiral wrap being intermeshed with said first spiral wrap, said first scroll member being mounted for limited axial movement with respect to said second scroll member, said first scroll member being biased toward said second scroll member by a pressurized fluid disposed within said recess;

a drive member for causing said scroll members to orbit relating to one another whereby said spiral wraps will create pockets of progressively changing volume between a suction pressure zone at suction pressure and a discharge pressure zone at discharge pressure;

a ring rotatably disposed on said outer surface of said first scroll member for opening and closing said fluid passage, said pressurized fluid being released when said ring opens said fluid passage whereby said first scroll member will move axially with respect to said second scroll member to open a leakage path between said suction pressure zone and said discharge pressure zone; and

a seal disposed between said first scroll member and said ring, said seal sealing said fluid passage when said ring closes said fluid passage.

2. The scroll machine according toclaim 1, wherein said pressurized fluid is released to said suction pressure zone of said scroll machine.

3. The scroll machine according toclaim 1, wherein said valve assembly is a solenoid valve.

4. The scroll machine according toclaim 3, wherein said solenoid valve is operated in a pulsed manner to modulate the capacity of said scroll machine.

5. The scroll machine according toclaim 1, wherein said pressurized fluid is at a pressure between said suction pressure and said discharge pressure.

6. The scroll machine according toclaim 1, further comprising a linear actuator for rotating said ring.

7. The scroll machine according toclaim 1, further comprising a valve member for rotating said ring.

8. The scroll machine according toclaim 7, wherein said valve member is a solenoid valve.

9. The scroll machine according toclaim 8, wherein said solenoid valve is operated in a pulsed manner to modulate the capacity of the scroll machine.

10. The scroll machine according toclaim 1, wherein said seal comprises a first lip seal in engagement with said ring.

11. The scroll machine according toclaim 10, wherein said seal comprises a second lip seal in engagement with said first scroll member.

12. The scroll machine according toclaim 1, wherein said seal comprises a lip seal in engagement with said first scroll member.

13. The scroll machine according toclaim 1, wherein said seal engages said first scroll member and said ring when said ring opens said fluid passage.

14. The scroll machine according toclaim 1, wherein said seal is disposed within a counterbore defined by said first scroll member.

15. The scroll machine according toclaim 14, wherein said seal comprises a first lip seal in engagement with said ring.

16. The scroll machine according toclaim 15, wherein said seal comprises a second lip seal in engagement with said first scroll member.

17. The scroll machine according toclaim 14, wherein said seal comprises a lip seal in engagement with said first scroll member.

18. The scroll machine according toclaim 14, wherein said seal engages said first scroll member and said ring when said ring opens said fluid passage.

19. The scroll machine according toclaim 14, wherein said seal is a self-actuating seal.

20. The scroll machine according toclaim 1, wherein said seal is a self-actuating seal.

21. A scroll machine comprising:

a first scroll member having a first spiral wrap projecting outwardly from a first end plate;

a second scroll member having a second spiral scroll wrap projecting outwardly from a second end plate, said second spiral wrap being intermeshed with said first spiral wrap;

a drive member for causing said scroll members to orbit relating to one another whereby said spiral wraps will create pockets of progressively changing volume between a suction pressure zone at suction pressure and a discharge pressure zone at discharge pressure;

a ring rotatably disposed on an outer surface of said first scroll member for opening and closing a fluid passage, extending from a first fluid pocket to the outer surface of said first scroll member; and

a seal disposed between said first scroll member and said ring, said seal sealing said fluid passage when said ring closes said fluid passage.

22. The scroll machine according toclaim 21, wherein said fluid passage communicates with said suction pressure zone of said scroll machine when said ring opens said fluid passage.

23. The scroll machine according toclaim 21, wherein said valve assembly is a solenoid valve.

24. The scroll machine according toclaim 21, further comprising a linear actuator for rotating said ring.

25. The scroll machine according toclaim 21, further comprising a valve member for rotating said ring.

26. The scroll machine according toclaim 25, wherein said valve member is a solenoid valve.

27. The scroll machine according toclaim 21, wherein said seal comprises a first lip seal in engagement with said ring.

28. The scroll machine according toclaim 27, wherein said seal comprises a second lip seal in engagement with said first scroll member.

29. The scroll machine according toclaim 21, wherein said seal comprises a lip seal in engagement with said first scroll member.

30. The scroll machine according toclaim 21, wherein said seal engages said first scroll member and said ring when said ring opens said fluid passage.

31. The scroll machine according toclaim 21, wherein said seal is disposed within a counterbore defined by said first scroll member.

32. The scroll machine according toclaim 31, wherein said seal comprises a first lip seal in engagement with said ring.

33. The scroll machine according toclaim 32, wherein said seal comprises a second lip seal in engagement with said first scroll member.

34. The scroll machine according toclaim 31, wherein said seal comprises a lip seal in engagement with said first scroll member.

35. The scroll machine according toclaim 21, wherein said seal is a self-actuating seal.

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