US2287841A - Fluid transfer apparatus - Google Patents

Description

.June 30, 1942. w. T. TABB 2,287,841

FLUID TRANSFER APPARATUS Filed Oct. 22., 1940 2 SheetsfSheet l f '.2 51 41 2 fr@ 40 5 4 53 5s 5457 June 30, 1942.

W. T. TABB FLUID TRANSFER APPARATUS Filed Oct. 22, 1940 2 Sheets-Sheet 2 f- BY y rnl WVM ATTORNEYS phragm only inwardly.

Patented June 30, 1942 2,287,841 ramp TRANSFER APPARATUS Warner T. Talib, Brooklyn, N. Y., assignor, by mesne assignments, to Reconstruction Finance Corporation, New York, N.

. the United States Y., a corporation of Application October 22, 1940, Serial No. 362,179

17 Claims.

The present invention relates to fuid transfer apparatus and moreparticularly to pump apparatus adapted to effect transfer of uids either liquid or gaseous for a variety of purposes.

V General objects of the inventionare the provisions of such apparatus which is of simple and economical construction with minimization of leakage tendencies, requires littleif any carefulv and costly machining and treating of cooperating parts frictional engagement between which is relatively minimized thus reducing tendency of wear which might eventually require replacements or repair, can be readily and easily assembled and disassembled, is eicien't in operation to transfer fluid eiectively at a relatively uniform rate with surging and pulsation of pumped medium reduced to a minimum, and is capable of eilicient high frequency operation; and structural embodiments of such apparatus which can readily and economically be made and assembled in mass production while assuring eiclent use and operation thereof,

More specic objects of the invention are the provision of such apparatus characterized by a pump chamber 'formed b y cooperation of a casing and a diaphragm having lateral rigidity and certain spring characteristics with diaphragm biasing leaf-like spring structure having certain spring characteristics mounted in the cham-` ber in a manner to provide certain net spring characteristics for combined diaphragm and spring construction; and to provide such apparatus wherein the mounting and characteristics of said diaphragm structure are such that an outwardly projecting diaphragm operating member mounted on the diaphragm is properly andeiciently guided in its operation without necessitating use therefor of bearing supports or like guiding means whichmight tend to introduce undesirable problems o f construction, manufacture and wear; and which assure efficient operation of said apparatus by mechanical means that may tend in operation to iiex said dia- Another object of the invention is the provipast a diaphragm biasing spring disc structure substantially horizontal and the pump chamber thereabove which may be termed the vertical pump position, it is particularly effective for continuous eicient operation when mounted in suchvertical pump positiongthe casing structure defining at least a portion of the pump chamber, the inletand outlet passages. communicating therewith and valves structures in the passages being such and cooperating in a manner as to assure effective escape of indrawn relatively light foi-.eign uid, such as air o r gaseous liquid when a liquid, e. g. hydrocarbon fuel, is being transferred by the pump.

A still further object of the invention is to provide such diaphragm pump apparatus of such construction as to permit easy and economical provision of simple and effective priming means,

manually operable if desired, which requires no particular provision of packingto prevent leak-v age, which can be simply mounted and de-4 mcunted without affecting assembly of other parts, and'which can be manipulated effectively to discontinue transfer operation of the pump apparatus without disturbing mechanical means effecting such transfer operation. A

'.An additionalobject of the invention is the provision of such diaphragm pump apparatus characterized by effective provision in the inlet and/or outlet passages of simplified pulsation' eliminating means whereby surging of and pulsations in supplied and/or delivered fluid, such as liquid fuel, is effectively minimized assuring eflicient and relatively uniform supply and/oi` delivery thereof.

Other objects of the invention will in part be;

obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements and arrangement of parts, which will be exemplified. in the construction hereinaftervsety forth and the scope of the-invention will be indicated in the claims. l

For a fuller understanding of the nature and objects of thevinvention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in

within the pump chamber of such a diaphragm pump, either through 'the diaphragm or around the periphery thereof, which assures' eilicient use androperation thereof.

A further object of the invention is to provide suchdiaphragm pump structure which, though adapted to' effect operation when mounted in a position other than with the diaphragm thereof which:

Fig. 1 is ,a top plan view of one embodimentof the apparatus of the present invention;

Fig. 2 is a sectionalview taken on line 2-2 of Fig. 1;

Fig. 3 is a top plan view of the structure shown in Figs. 1 and 2 but with parts removed and broken away; and

desired biasing action. ture has certain spring characteristics as does Fig.'4 is a sectional view taken on line 4-4 of Fig. 1.

Various diaphragm pump structures have been v proposed for use in transferring fluids, both gaseous and liquid. For example, such structures have been proposed for use in both mechanical and electrical gasoline injection systems as well as for use in fuel supply systems of internal combustion engines of the Diesel type, oil burners and the like. Many of such structures, however, have been of such construction as to require extremely careful and costly machining and fitting of parts, treating of material to'harden frictionally engaging parts, and costly and frequently inefficient provisions of packing to prevent leakage; and have been complicated making assemply and disassembly diiiicult, subject to wear of frictionally engaging parts making repair or replacement of parts eventually necessary, and inefficient and non-uniform in operation, Further, such structures have been such as to make their use in systems requiring high speed operation, for example fuel supply systems for internal combustion engines, extremely uncertain and unsuitable.

These and other difliculties are efficiently alleviated by the apparatus of the prent invention which `has been found to be highly satisfactory for use, by way of example. in fuel supply systems for Diesel engines. I'he diaphragm pump structure of the invention has no working parts characterized by frictional engagement of guiding bearings, other than a roller, if desired, used as a cam follower to impart movement to a diaphragm operating member or rod. IThe diaphragm operating member is preferably anchored to the diaphragm to project voutwardly therefrom free from any bearing support. It is guided.

in its operation solely by the diaphragm having lateral rigidity mounted with peripheral portions thereof seated on a casing cooperating with `the former to form a chamber. A leaf-like spring structure is mounted in the chamber with outer portions thereof rigidly supported by the casing and forms a biasing abutment for the central portion of the diaphragm structure t'o obtain the 'I'he diaphragm structhe spring 'structure and these are so correlated as to give net spring'characteristics for the combined spring and diaphragm structures as to make for desired action.

Such spring structure may be in the form of one or more laminae of sheet metallic material of any suitable configuration such as a hub portion with two or more, radiating arms but preferably comprises one or more discs of spring steel or the like, preferably cup-shaped. When such discs are used'provision is made for pas-y sage of fluid therepast by any suitable means such as apertures or cut-outs therein but preferably by providing in the casing a series of spaced apart seats around the circumference thereof with intermediate passage spaces.

The diaphragm structure preferably comprising one or more discs of steel or other resilient metallic material having desired lateral rigidity may be assembled on or anchored to the operating member in any suitable manner but prefer-V ably is centrally apertured to receive the inner end of the operating member or rod which projects therethrough to receive a nut or collar,

The central-portion of the spring structure, to form a biasing abutment for the diaphragm structure, may be secured centrally to the dia.-

phragm structure in any suitable manner and have lateral clearance with its supporting means but for simplicity of manufacture and assembly it is preferred to provide a central hole in the spring structure which receives with clearance the projecting end of the operating rod or the nutA or collar anchoring the latter in position.

Inlet and outlet passages having valves therein are provided in the casing to communicate with the pump chamber. The apparatus may be used efficiently in a variety of positions but preferably is mounted vvertically with the passages communicating with the chamber through the top of the casing and the valves therein positioned angularly with respect to each other. The

portions of the seats of said valves, preferably of the check valve type, nearest each other are at highest elevation with -that of the outlet valve above that of the inlet valve. This permits effective escape at each pump cycle of indrawn relatively -light foreign iiuid, such as air and gaseous fuel4 when liquid fuel is being transferred, whereby tendency to build up in the pump chamber a body of such foreign fluid or gaseous matter that might eventually prevent efficient operation of the pump is eliminated.

Provision is made for manually or otherwise priming'the apparatus. This is accomplished by means exterior of the chamber whereby necessity for packing and tendency of leakage are eliminated. Suitable mechanism permits raising or moving inwardly the diaphragm operating member.' Preferably a member or shaft is rotatably mounted on the apparatus exteriorly of the chamber preferably on a base member supporting the diaphragm and casing. 'Ihe inner end thereof may \.be provided with a cam or the like or so shapedas to engage means such as ashoulder on the operating rodrto impart to the latter the desired movement when the priming member or shaft is rotated. When operating the apparatus by a cam with the outer endof theoperating rod biased .to the external surface thereof to act as a cam follower the priming mechanism may be utilized to arrest uid transfer operation of the apparatus merely by rotating the shaft and holding it in rotated position to raise the cam follower free from the cam and hold itin raised position.

When the apparatus is used for transferring liquid it is desirable to eliminate pulsations or surges in delivered uid and/or in .liquid being supplied to the diaphragm pump. Pulsations or surge's in delivered liquid might interfere with required degree of uniformity of feed and similar pulsations in the supply might interfere with efllcient operation of the transfer pump. Should the pump be operated at times when pulsations were building up pressure in the 4supply to the pump and at other times when pulsations were reducing the pressure the transfer operation of the pump might well vary, affecting delivery of fluid undesirably. Pulsations are effectively eliminated by the apparatuswith the provision of means each comprising a flexible diaphragm backed by a body oi' trapped gas forming a portion of the wall of the duid passage near the valve in the passage. As pointed out previously such provision may be made in either or both the inlet and outlet passages.

Referring to the drawings like numerals refer to like parts throughout. A base member or plate I0 is provided with an annular seat I I upon which seats the periphery of a diaphragm i2. 'I'he diaphragm i2 may comprise one or more with the seat on the base I to clamp the diaphragm I2 and gaskets I3, 'I3 therebetween in a l fluid-tight manner, suitable screws |6-I6 being used to clamp the parts together.

An operating member or a rod |1 is anchored centrally to the diaphragm I2 to project outwardly therefrom. This member preferably comprises a fork I8 between the legs of which is rotatably mounted a roller I9 constituting a cam follower adapted to ride on the outer surface of acam 20. A ange 2| at the base of the operating member I1 provides a bearing shoulder for a central portion of the diaphragm |2 and aninner stud end 22 thereof projects through a central aperture in the diaphragm I2 and is externally threaded to receive anut 23 between which and the ange 2| is clamped the diaphragm structure withaninterposed washer 24 and suitable gasket rings 25,25.

The base member I0 is provided centrally with a.hole 26 larger than the operating rod I1 and the roller I9 carried thereby to permit without l contact free reciprocation of the latter therethrough.

The diaphragm I2 and the casing |4 cooperate to provide apump chamber 21 on the side walls of which are formed a plurality of vcircum-` ferentially spaced seats 28-28 providing a plurality'of intermediateuid passages 29-29 past the seats 28-28. A diaphragm biasing leaf-like spring structure 30, preferably formed of one or more laminae of sheet steel of disc configuration is mounted in thechamber 21 with its periphery supported on the seats 28-28 preferably with at least small'lateral clearance. Thisspring structurel 30 ls provided with a central mum iiexure of the diaphragm, such as the innermost position of the diaphragm and associated parts of the structure shown in the drawings. Further in such a structure those characteristics may tend to prevent the cam follower from eiectively following the cam in the outermost position of the diaphragm. The plotted curve of those 4diaphragm characteristics is found to be of great curvature indicating that the rate of change of positive and negative pressures may be of an objectionable degree under certain conditions making it advisable to use very small diaphragm deflections.

This may be compensated for or eiectively corrected by the use of au initially cupped spring which has a reverse spring characteristic curve. Net spring characteristics of the combination oi such diaphragm and spring structure can thus be obtained which will assure approximately uniform pressure of the cam follower on the cam. Even a less pressure in theinnermost position of the diaphragm than in the neutral or outermost positions thereof, or greater pressure in the latter position than when in the neutral position, may be attained by proper predetermined combinations. present pump construction while making 'for simple and compact pump construction assures long life for the diaphragm and its operating mechanism and efficient pump performance with the use of' diaphragm and biasing spring structureof simple design.

The casing I4 is provided with a pair ofopposed bosses 32 and 33 having respectively'internally threadedrecesses 34 and 35 to receive v fluid supply and delivery conduits. The recess aperture 3| which engages over the inner `end 22 of the operating rod and the structure mounted thereon preferably receiving thenut 23 with at least small lateral clearance at points of greatest lateral dimension with the portions adjacent the aperture bearing against thewasher 24 to form. a biasing abutment for the ydiaphragm structure.

Thisspring structure 30 may be cupped and positioned as shown in the drawings. Obviously the positionof thespring structure 30 may be reversed provided the seats 28-28 andthe diaphragm structure or anchorage structure of the operating rod are suitably altered to accommodate such reversal. The position and shape of the spring structure will be largely dictated bythe results desired, the dimensions such as relation of thickness of spring structure to diameter, de-l gree of initial cupping, etc. For some purposes substantially at disc spring structure may be when not stressed. Equalization of -such travel v 34 communicates through thepassage 36 with afluid passage chamber 31 closed at the top by aremovable cap 38 on the inlet side and asimilar passage 39 communicates with asimilar chamber 40 closed by asimilar cap 4| on the outlet side. Thechambers 31 and 40 constitute the inner ends of the inlet and outlet fluid passages communicating with thepump chamber 21 through suitable valve ,structure located therein. These valves preferably are of the check valve type so mounted in their respective chambers as to permit fluid to iiow into the pumpchamber -21 from the inlet side ,and fluid to ow out of the pump chamber on the outlet side, as indii f cated in the drawings.

Thecheck valve 42 in theinlet chamber 31, as is more Afully described in my `copending application Serial No.`362,l80 filed October 22, 1940,v comprises a sleeve-like cage 43 having aseat 44 formed thereon against whiclris biased-aValve plate 45 by a leaf-like spring structure. 46 centrally apertured to receive astud structure 41 preferably anchored to thevalve plate 45, with spacing means 46 interposed between thevalve plate structure 45 and the spring structure '.46

` to form opposed abutments whereby the valve results in the least strain onthe diaphragm. ll '.'he

use of a at spring structure assures compactness of pump construction.

A fiat or initially uncupped diaphragm, such as that shown by way of example in the drawings, has certain well defined characteristics as' a spring in and of itself. These are such as may tend to result in excessive pressure of the cam follower against the cam in the positions of maxiplate can be biased to its seat and the parts of the valve assembled in the cage 43'by asplitf ring 49 seated within a groove in thecage 43 and bearing against peripheral kportions of thespring structure 46. The base of thecage 43 is machined out at 50 to form a taperedthroat for the valve port. y The'check valvein theoutlet chamber 40 is ,similar in construction to thecheck valve in theinlet chamber 31 except perhaps in one particular. The check valve on the inletside is-preferably provided with a hole 5| through theycage 43 which communicates with the annular recess A Thus the spring rigging of the ditions in a highly satisfactory manner.

adjacent to and surrounding the valve seat on the chamber side thereof at substantially its highest point as shown. Such a hole having no purpose in the check valve or the outlet passage maybe omitted. In the crown of the domed chamber wall adjacent the taperedthroat 50 of theoutlet valve cage 43 at its point of highest elevation is machined away 52 to cooperate with the surface of thethroat 50 of the outlet valve.' the upwardly inclined inner surface of thepump chamber 21 and the hole 5I, to provide an escape way for relatively light foreign fluid that may be drawn into the pump chamber with the fluid being transferred, for example, air and fuel fumes, when hydrocarbon fuel is being transferred. This will prevent undue accumulation of gaseous medium in the transfer pump chamber which might tend to affect efficient operation thereof and possibly prevent in the ultimate any transfer of fluid.

Pulsation eliminators are provided in the inlet and outlet passages by formingrecesses 53,

53 in thecaps 38 and 4I and trapping a body of air therein byflexible diaphragms 54, 54 of the device all of the parts thereof can easily and readily be assembled from the top.

In operation when the operating rod is lifted upwardly by a cam the resultant inward flexing of the diaphragm against the biasing actionof the spring structure minimizes the space of the pump chamber and when, the cam permits the operating rod to be moved outwardly by the biasing spring structure partial vacuum is created in the pump chamber producing a differential in pressure on opposite sides of the inlet valve sufflcient to open the same and cause fluid to flow into the pump chamber. When the operating rod is again moved inwardly the inlet valve automatically closes, and pressure built up in the pump chamber by inward flexing of the diaphragm causes the outlet valve to unseat and fluid to be delivered through the outlet passage from the pump chamber. When the biasing spring structure is again permitted to move the diaphragm outwardly the outlet valve automatic'ally closes and the cycle is then repeated. Thepulsation eliminator diaphragms 54, 54,` having bodies of compressible fluid, such as air trapped therebehind, and forming walls of the inlet and outlet passages, effectively damp pulsations in the supplied and delivered liquid, which pulsations as through one leg of the roller fork. A radially extendingboss 59 on the base I0 is bored to receive rotatably ashaft 60 having a circumferential groove GI in which the end of a pin or setscrew 62 seats to hold the shaft in position. Theinner end 63 of theshaft 60 is machined off on the top side thereof to form a pair ofcamming portions 64, 64 one of which is adapted to bear against the shoulder 5.1 when theshaft 60 is roiated in a clockwise or counter-clockwise direction thereby to lift the operating rod and flex the diaphragm inwardly against the biasing spring soas to raise the cam roller I9 from thecam 20. Anoperating arm 65 is keyed to theshaft 60 for rotating it and a coil spring 8B around is well known tend to occur in such systems through operation of transfer pumps and check valves thereof. The pump apparatus may be manually primed by flexing the diaphragm inwardly and outwardly a number of times, which can be accomplished by pulling on the priming arm, releasing it and repeating the operation. Operation yof the transfer pump may be arrested by pulling on the priming arm and holding it.

It will be understood that the transfer pump structure of the. invention is not limited to the use of a flat `or initially uncupped diaphragm.

the end of theshaft 60 having-one end thereof Y termined by a stud 6l bearing against4 the edge of the casing I4.

By way of example the transfer pump of the Ypresent invention may be mounted by means of mounting ears (5B-B8 on the base member Ill Y upon the case of a high pressure injecting apparatus for feeding fuel to a Diesel engine Such injecting apparatus may comprise a plurality of high pressure injecting pump devices, one for each cylinder of the engine, all operated by a common cam. The circumferential surface of this cam may be provided with lobes equal in number tothe number of high pressure injecting devices so that each revolution of the cam, such as 20, will result in a number of complete transfer pump cycles equal to the number of high pressure injecting devices each of which is operated during one cam revolution. VSuch operation obviously will be of very high frequency and it has been found that the apparatus of the present invention with the provision of diaphragm travel of about .0125" on each side of the neutral position will perform its functions under such con- It will further be noted that with such a mounting of Obviously an initially cupped diaphragm could be used when desired, the associated structures being altered in shape and/or dimensions suitably to accommodate the same, or one might use diaphragms of other configurations, such as corrugated, etc., when the inherent characteristics thereof contribute certain desired action. Of course such diaphragms also have definite spring characteristics and that 'which is set forth above as to net spring characteristics of combined diaphragm and spring constructions is generally applicable to constructions including cupped or corrugated diaphragms, and the like. 4

The outer edge of the diaphragm may be rigidly clamped in mounted. position, or may be resiliently supported to a certain extent by the use of gaskets such as I3, I3 if formed from resilient material provided the clamping force is not so great as entirely to eliminate such feature. With the spring structure constructed and mounted asv disclosed where at least small clearance is provided between the casing and outer edge of the spring structure and/or between the edge of spring structure at the central aperture and structure on the diaphragm received therein it will be understood there may be some guiding action of the diaphragm flexing mechanism under certain conditions of operation.

It will thus be seen that the .objects set forth above are efficiently attained by apparatus of the present invention and since certain changes may be made in the above construction and different embodiments ofthe invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention what I claim as new and desire to secure by Letters Patent, is:

1. Fluid transfer apparatus comprising, in combination, a casing, a resilient diaphragm structure having lateral rigidity and certain spring characteristics peripherally mounted on said casing to form therewith a pump chamber, an outwardly projectingv operating member rigidly mounted on said diaphragm by attachment thereto for substantial alignment of said member free from any bearing support, a diaphragmbiasing leaf-like spring structure having certain spring characteristics positioned in the chamber with outer` portions thereof seated on said casing and the central portion thereof forming an abutment for said diaphragm structure, and means between substantially the central portions of said spring structure and said diaphragm structure to cause them to operate together to attain certain net spring characteristics.

2. Fuid transfer apparatus comprising, in combination, a casing, a resilient diaphragm having lateral rigidity and certain spring characteristics peripherally mounted on said casingV to form therewith a pump chamber, an outwardly projecting operating member rigidly mounted on said diaphragm free fromany bearing support, means secured to said diaphragm projecting on the chamber side thereof, and diaphragm-biasing `spring disc structure having peripheral portions thereof seated on the casing within the chamber and its central portion engaging said projecting means in a manner to cause said structures to operate together to attain certain net spring characteristics.

3. Fluid transfer apparatus comprising, in

combination, a cupped casing, a resilient dia-4 phragm having lateral rigidity and certain spring characteristics peripherally mounted on said casing to form therewith a pump chamber, operating means rigidly anchored to said diaphragm to form a member projecting into the chamber and an operating rod extending outwardly fromsaid diaphragm free from any bearing support, and a diaphragm-biasing spring disc structure having peripheral portions thereof seated on the casing within the chamber and its central portion engaging said projecting member in a manner to cause said structures t0 O perate together to attain certain net spring characteristics.

4. Fluid transfer apparatus comprising, in

I combination, a cupped casing, a resilient diaphragm having lateral rigidity and certain spring characteristics peripherally mounted on said casing to form therewith a pump chamber, .operating means rigidly 'anchored to said diaphragm to form a member projecting into the chamber and an operating rod extending outwardly from said diaphragm'free from any bearing support, and a diaphragm-biasing spring disc structure having its periphery seated on the` casing within the chamber at spaced apart points 'to form intermediate Vfluid `passages and its central portion engaging said projecting. member in a manner to cause said structures to operate together to attain certain'net spring characteristics. Y

5. Fluid transfer apparatus comprising, in

combination, a cupped casing, a resilient diaphragm having lateral rigidity and certain/spring characteristics peripherally mounted on said casing to form therewith a pump chamber, an operating rod rigidly anchored centrally to said diaphragm with the inner end thereof extending through the diaphragm into the chamber and the outer end thereof extendingfrom said diaphragm free from any bearing support, and a cupped spring'disc structure having itsperiphery seated on the casing within the chamber at spaced apart points to form intermediate fluid passages, said spring structure biasing said diaphragm with the inner end of said rod engaging the central portion of said disc structure in a manner to cause said structures to operate together to attain certain net spring characteristics.

6. Fluid transfer apparatus comprising, in combination, a cupped casing, a resilient metal diaphragm having lateral rigidity and icertain spring characteristics peripherally mounted on said casing to form therewith a pump chamber, inlet and outlet valves communicating with the chamber, an operating rod rigidly anchored centrally to said diaphragm in such manner as to form a projection on the chamber side thereof, said rod extending outwardly from said. dia- 'phragm free from any bearing support and terminating in acam follower, a pluralityV of circumferentially spaced seats inside the chamber, and

a cupped spring disc structureperipherally supjection engaging thecentral portion of said disc' structure in a manner to cause said structures to operate together to attain certain net springv characteristics. y

7. In uid transfer apparatus, the combination comprising a resilient diaphragm structure having certain spring characteristicsperipherally mounted for laterally inward movement of outer portions thereof during fiexure, means to flex said diaphragm, a diaphragm-biasing leaf-like spring structure having certain different spring characteristics mounted with outer portions thereof supported, and thrust means between substantially the central portions of said diaphragm and spring structures causing them to operate together to attain certain net spring characteristics of the assembly making for desired action.

8. In uid transfer apparatus, the. combination comprising a resilient diaphragm structure having certain spring characteristics peripherally mounted for laterally'inward movement of outer portions thereof during flexure, means to iiex said diaphragm, a diaphragm-biasing leaf-like spring structure having certain spring characteristics substantially the reverse of those of said diaphragm structure mountedv with outer portions thereof supported', and thrust means between substantially the central portions of said dia" phragm and spring structures causing them to diaphragm structure by attachment thereto for substantial alignment of said member free from l any bearing support, and a diaphragm biasing spring structurey positioned in the chamber with outer portions thereof seated on said casing and a central portion thereof forming an abutment forsaid diaphragm structure.

10. Fluid transfer apparatus comprising, in combination, a casing, a resilient diaphragm structure having lateral rigidityperipherally.

. l11. Fluid transfer apparatus comprising. in t combination, a cupped casing, a resilient metal centrally apertured diaphragm having lateral rigidity and certain spring characteristics resiliently mounted at its periphery on said casing in a substantially fluid-tight manner to form there with a pump chamber, inlet and outlet valves communicating with the chamber, an operating rod extending through the aperture in said diaphragm and anchored thereto by resilient gasket means with one end comprising projecting means in. the chamber and the other end extending outwardly from said diaphragm free from any bearing support and comprising operating means, and a leaf-like spring structure comprising a washer-like spring member having outer portions thereof supported on said casing and of a diameter less than the internal diameter of the chamber, said spring structure biasing said diaphragm with said projecting means engaged in the central aperture of said washer-like spring member with the greatest transverse dimension of said projecting means being less than the diameter of the spring aperture.

12. Fluid transfer apparatus comprising, in combination, a cupped casing, a resilient metal centrally apertured diaphragm having lateral rigidity and certain spring characteristics resil.

' iently mounted at its periphery on said casing in a substantially fluid-tight manner by resilient gasket means to form therewith a pump chamber, inlet and outlet valves communicating with the chamber, an operating rod extending through the aperture in said diaphragm and anchored thereto by resilient gasket means with one end comprising projecting means in the-chamber and the other end extending outwardly from said diaphragm free from any bearing support and comprising operating means, a plurality of circumferentially spaced seats inside the chamber, and a leaf-like spring structure comprising a washer-like spring member having outer portions thereof supported on said seats and of a diameter less than the internal diameter of the chamber to provide fluid passages intermediate said seats, said spring structure biasing said diaphragm with said projecting means eng-aged in the central aperture of said washer-like spring member with the greatest transverse dimension of said projecting means being less than the diameter of the spring aperture.

13. Fluid transfer apparatus comprising, in combination, a casing,`a resilient initially substantially flat diaphragm structure having lateral rigidity and certain spring characteristics with outer edges thereof mounted on'said casing latter compensate for those of the former to atfor laterally inward movement .of outer portions of said diaphragm structure during fiexure thereof and to form with said casing a pump chamber, means to flex said diaphragm, and a diaphragm-biasing leaf-like spring structure comprising a cupped washer-like spring member having` certain spring characteristics substantially the reverse of those of said diaphragm structure mounted'with 'outer portions thereof supported on-said casing. said spring structure being arranged in the chamber with the cupping thereof facing away from said diaphragm and the central portion of the former biasing the latter so that the spring characteristics of theformer compensate for those of the latter to attain certain net spring characteristics and assure approximately uniform pressure on the diaphragm flexing means throughout operative cycles.

14. Fluid transfer apparatus comprising, in'

combination, a casing, a resilient initially sub` stantially flat diaphragm structure having lateral'rigidity and certain spring characteristics 2lil with outer edges thereof mounted on said casing to form a pump chamber, means to flex said diaphragm, 'a diaphragm-biasing leaf-like spring structure comprising a washer-like spring member having a substantially centrally located aperture and certain spring characteristics substantially the reverse of those of said diaphragm structure mounted with outer portions thereof supported onsaid casing, and thrust means between substantially the central portion of said diaphragm structure and said spring structure having a portion projecting into the aperture in said spring member causing them to operate t0- gether so that the spring characteristics of the tain certain net spring characteristics and assure approximately uniform pressure on the diaphragm exing means throughoutoperative 15. Fluid transfer apparatus comprising, in combination, a casing, a resilient initially substantially flat diaphragm structure having lateral rigidity and certain spring characteristics with outer edges thereof mounted on said casing to form a pump chamber, means to flex said diaphragm, a diaphragm-biasing leaf-like spring structure comprising a washer-like spring member having a substantially centrally located aperture and certain spring characteristics substantially the reverse of those of said diaphragm structure mounted with outer portions thereof supported on said casing, and thrust means between substantially the central portion of said diaphragm structure and said spring structure having'a portion projecting into the aperture in said spring member causing them to operate together so that the spring characteristics of the latter compensate for those of the former to attain certain net spring characteristics and assure approximately uniform pressure on the diaphragm flexing means throughout operative cycles. said spring member being of a diameter less thanv the internal diameter of the chamber and the greatest transverse dimensionof said protially fluid-tight manner by resilient gasket means to form a pump chamber, means to flex I said diaphragm, anda diaphragm-biasing leaf-v like spring structure comprising a cupped washerlike spring member having certainspring characteristics substantially the reverse of those oi said diaphragm structure mounted with outer portions thereof supported on said casing, said spring structure being arranged in the chamber with the cupping thereof facing away from said diaphragm and the central portion of the former biasing the latter so that the spring characteristics of the former compensate for those ot the latter to attain certain net spring characteristics and assure approximately uniform pressure on the diaphragm fiexingmeans throughout operative cycles.

17. Fluid transfer apparatuscomprising in combination, a casing, a centrally apertured resilient initially substantially flat diaphragm structure having lateral rigidity and certain spring characteristics with outer edges thereof resiliently mounted on said casing in a substantially uid-tight manner by resilient gasket means to Vi'orm a pump chamber. thrust means anchored in the aperture in said diaphragm by 'resilient gasketmeans and projecting into vthe chamber, means to iex said diaphragm, and a .diaphragm-biasing leaf-like spring structure comprising a washer-like spring member having certain. spring characteristics substantially the reverse of those of said diaphragm structure mounted with outer portions thereof supported on said Acasing and having said thrust means -received in the aperture therein causing said diaphragm structure andsaid spring structure to operatetogether so that the spring characteristics of th latter compensate for those of the former to'attain certain net spring characteristics and assure approximately uniform pressure` on the diaphragm exing means -throughout operative cycles.

WARNER T. TABB.

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