PH26495A - Valve assembly - Google Patents

Description

VALVE ASSEMHOLY

' | This is a division of application Serial No. 23443 filed on Dec, 20,1979, now Phil, Patent No, 16984 issued on May 4, 1984,

BACKGROUND AND SUMMARY OF THE INVENTION

: The present invention relates generally to pressure responsive valve assemblies and more partie . cularly to such valve assemblies adapted for use in reciprocating piston type compressors, such as refrie geration compressors.

Reciprocating piston type compressors typical ly employ suction and discharge pressure actuated valving mounted at the end of the cylinder between the head and cylinder housing. In designing these valve assemblies it is of critical importance to overall system operation to provide a sufficiently large port area to permit the flow of a maximum volume of fluid within a given time period and at an acceptably small . pressure drop. This is particularly true for refri= : geration compressors employed in air conditioning systems because of the relatively high mass flow rates generally required in such systems.

Associated and conflicting with the desirability to maximize port area for a given size cylinder is the . . need to reduce the weight of the moving valve member go as to limit the inertia effect thereof. Noise of ' operation should also be minimized. These aspects take on increasing importance with high speed compres 50r8.

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Another important design objective is to minimize the reexpansion or clearance volume of the cylinder. The valving and cylinder top end wall should have a shape complementary with that of the top of the piston and as flat as possible to enable the piston to reduce the volume of the compression chamber to an absolute minimum during the compression stroke without restricting gas flow. While it may be possible to accomplish this objective by design of com- . plex piston head shapes, manufacturing thereof becomes expensive, assembly more difficult, and throttling losses generally occur as the piston approaches top dead center.

Reduction of reexpansion volume is of great importance in refrigeration compressors having relatively low mass flow rates, such as those units employed in very low temperature refrigeration systems, as well as in units for heat pump applications.

It ie therefore the primary object of this in- vention to provide an improved valve and an improved valve and seat combination for use as a discharge valve in a reciprocating gas compressor, such as, for exam- ple, the compressors used in pefrigeration equipment, ‘which valve and valve-seat combination improves the efficiency of the compressor and is characterized by oo 25 its improved flow characteristics at all valve lifts, oo wl} /

good sealing without permanent deformation of the valve, long life, quietness in operation and ites ability to operate in high speed compressors.

The present invention provides an improved valve assembly utilizing a valve member the entire area of which is subjected to valve actuating pressure differentials and which is fabricated in a light-weight manner so that high force to weight ratios are obtained for a given port size. This maximizes acceleration and hence efficiency, especially at high speeds. Fure ther, the design of the valve member and associated valve plate is such as to present a substantially flat flush end wall for the compression chamber. Thus, the reexpansion volume for the compression chamber is subse tantially reduced over conventional valving arranges ments and simple flat topped pistons (or pistons with a minimum of top surface contour) can be used. Also, ) because of the lightweight characteristice of the valve member, valving action is faster and port size may be increased without detrimental inertial effects. The use of a polymeric material for the valve member in the preferred embodiment and the relative geometries of the valve member and valve seat also reduce valve noise generated by the recurring impact of the valve member and valve seat. With the present invention / “5 = ’ J valve port area is not a function of reexpansion volume; ; each can be optimized independently. Therefore, the valve assembly of the present invention is ideally suited for use both in air conditioning applications as well as heat pumps and low temperature units. Furw ther, the present arrangement can be used to maximize the use of the cylinder head area for valving.

Additional advantages and features of the pre sent invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bottom plan view (from inside the . cylinder chamber) of a pressure responsive discharge valve assembly utilizing a polymeric valve member in accordance with the present invention, shown in combi-

J nation with a reed type suction valve;

FIG. 2 is an inverted sectional view of the valve assembly of FIG. 1, the section being taken along : ao line 2~2 thereof; :

FIG. 3 is an inverted sectional view of the valve assembly of FIG. 1, the section being taken along line 3-3 thereof; | :

FIG. 4 is an enlarged fragmentary view of a por- tion of a valve seat and associated valve member in

Co “6

' accordance with the present invention illustrating in an exaggerated manner the relative angles of in- clination of the mating surfaces thereof, the valve member being shown in a position in which it is just : 5 beginning to seat;

Lo FIG. 5 is a sectional view similar to and showing the valve assembly of FIG, 2 but illustrating it in combination with a ring type suction valve;

FIG. 6 is a bottom plan view (from inside the cylinder chamber) of another embodiment of the dis= charge valve assembly of the present invention, utie lizing a polymeric valve member; -

FIG. 7 is an inverted sectional view of the em- i bodiment of FIG. 6, the section being taken along line 7-7 thereof; : | FIG. 8 is a sectional view similar to and show= ing the valve assembly of FIG. 7 but illustrating it in combination with a reed type suction valvej

FIG. 9 is a fragmentary sectional view similar to that of FIG, 7 but illustrating yet another emb om diment of the discharge valve assembly of the present invention utilizing a polymeric valve member; and To

FIas. 10 through 15 are fragmentary sectional views similar to FIG. 4, but illustrating several em= bodiments of the valve member of the present invention /

A

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. formed out of metal.

DESCRIPTION OF THE PREFERRED EMBODIMENIS

Referring now to the drawings and in partie cular to FIGS. 1 through 3, there is illustrated a valve assembly in accordance with the present invenw tion indicated generally at 10. Valve assembly 10 comprises a conventional valve plate 12 having a pair of spaced suction passages 14 and 16 extending there- through and a combined discharge passage and valve seat 18. A conventional reed type suction valve memw ber 20 is also provided having an end portion 22 disw posed in overlying valving relationship to suction passages 14 and 16, an opposite end portion 24k secured to valve plate 12 and an elongated centrally disposed opening 26 overlying discharge passage 18, Recesses 29 are provided in the cylinder bore to provide clearance for the tips of the suction valve when it opens. The valve plate is mounted in the usual manner over a com= pressor cylinder defined by cylinder block 27 (in FIG. 1 the position of the cylinder bore is shown in phane : tom). ’

As best seen with reference to FIGS. 2 and 3, } discharge passage 18 is of a frusto conical shape be ing defined by outwardly diverging sidewalls 28, A discharge valve member 30 in the form of a frustow a.

conically shaped disc is disposed within discharge pasbage 18 with sidewalls 32 sealingly engaging side~ walls 28. As shown, discharge valve member 30 is of a size and shape relative to discharge passage 18 so as to place lower surface 34 thereof in substantially coplanar relationship to lower surface 36 of valve plate 12. Discharge valve member 30 is also provided with a recess 38 in upper surface 40 thereof which receives an end portion 42 of a biasing means in the form of a helical compression spring U4, the opposite end 46 of which extends upwardly into engagement with a recess 48 provided in a bridge-like retainer member 50, The valve is essentially pressure actuated, and epring 44 is chosen primarily to provide stability and also an initial closing bias and a preload to establish an initial seal.

Other types of springs than coil springs may of course be used for this pure pose.

Retainer member 504 which also serves as a stop to limit opening movement of the valve element, is secured to valve plate 12 by suitable fasteners 52 and She ‘ - Generally speaking, discharge valve member 30 : is preferably formed from a high performance polymeric : material, and preferably a molding resin, such as polyimide, aramid, polyester, polyphenylene sulfide, -9 ew and poly (amide-imide) resins. These materials have high strength, high temperature resistance are relatively lightweight, are unreactive, and are re=- . latively compli Although it is difficult to numerically define all of the desirable parameters for this material, it is thought that best results will be obtained using materials having a tensile strength to weight ratio greater than approximately 3.25 x 10° pei/lb_ and a flexural strength to flexural modulus ratio less than approximately 0.04, In addi- tion, the material should have a heat distortion tem- perature greater than 450°F. , high wear resistance, » high internal dampening characteristics (for noise attenuation and sealing), compatibility with the en- vironment, ease of manufacture (eegey by compression or injection molding), low creep rate, and a high impact strength (preferably having a notched Izod impact strength greater than approximately 0.8%).

At the present time the preferred material for the valve member is "Vespel", a polyimide resin availe able from duPont Company, Wilmington, Del. The com- : positions identified as "gpwl" and "SP~21" have been found to give excellent results. The use of such a polymeric composition for discharge valve member 30 facilitates easy fabrication, such as by molding, and the relative light weight of the valve member faci- litates high speed operation due to the reduced . inertia of the valve and the ability to use lighter springs, as well as reducing noise generated by con~ tact of the valve and valve seat. The "Vespel' mate~ rial is ideally suited for such application as it is able to resist degradation from relatively high tem- ' peratures and is unaffected by either refrigerant gas or lubricant. It has been found that the maximum operating temperature to which the refrigerant and lubricating oil can be subjected without damage is ’ less than that for "Vespel". ''Vespel' is also come pliant enough to seal without permanent deformation.

Other suitable polymeric materials having the noted characteristics which it is believed may also be used, include those commercially available under the trademarks "Vespel" KS (an aramid resin available from the duPont Company), "Sparmon" (a polyimide resin available from Sparta Mfg. Co., Dover, OHio), "Valox" 420 or 420~SEO (a glase reinforced, thermoplastie polyester available from the General Electric Co.y pPitésfield, Mass.), "Ryton" (a polyphenylene sulfide available from Phillips Petroleum Co., Bartlesville, Okla). and "Torlon" (a poly (amide-imide) resin available from

Amoco Chemicals Corpey Chicago, Ills). / “ll = ’ n

£8 shown in FIG. U4, sidewalls 32 of valve . member 30 are inclined relative to the center axis } of discharge passageway 18 indicated at 55, at an angle 56 slightly greater (when unstressed) than the angle 58 of inclination of sidewalls 28 of the valve seat or discharge passage 18, An initial seal is achieved when the valve member closes to the position shown in FIG. 4 i.e., when the thin outer sealing periphery 60 of sidewall 32 first engages sidewall 28. Because the pressure differentials across the valve element are relatively small during most of the elosure cycle, the primary closing force is that exerted by spring 44. Once an initial seal is ‘ achieved, however, a substantial pressure differential . 15 is created across the valve member as the compressor piston starts down from top dead center. This creates a substantial closing force which moves the valve mem~ ber from the initial seal position of FIG. 4 to the fully seated position of FIGS. 2, 3 and 5. Edge pore tion 60 deforms and becomes stressed as this seating takes place. The stress in edge portion 60 improves the degree of sealing and facilitates opening, but should not be so much as to cause permanent deformae tion of the valve member,

The valve member and spring are preferably dee signed so that the upward force exerted by the valve mamber a8 it unstresses and moves from its fully seated position to that shown in FIG. 4 is signifi= cantly greater than the downward force exerted on the valve member by spring 44 during this initial openw= . ing movement. This significantly assists opening of the valve because as soon as the pressure differential . across the valve member starts to reverse (l.e., after completion of the suction cycle and early in the dise charge cycle) the residual stress in the valve member causes it to immediately spring off the valve seat (overcoming the force of spring 44) towards its FIG. & position. This in turn immediately exposes the full - ' area of the valve member to opening pressure generated within the compression chamber. This exposure of a maximum effective area to opening or lifting pressure accelerates valve opening and permits higher speed operation. It should also be noted that the passage area between opposed sidewalls 28 and 32 will continue to increase as valve member 30 is moved upwardly, ] : thereby providing an extremely large area for fluid oo discharge with a given size port area, This provides . worthwhile increases in mass flow rate for a given . compressor speeds

It should be noted that when the valve member oo ) “13 = is fully seated (as in FIGS. 2, 3 and 5) the effec~ tive area thereof exposed to the pressure differential is that defined by discharge passage 18, i.e., a con=- .siderably smaller area than that defined by the outer periphery of the valve. Because it is desirable to use as light a weight construction as possible to maximize valve acceleration, it is thereby possible } to construct the valve sufficiently light (considering : material strengths and structural design) that it need not be able to accommodate (without excessive or perma= nent deformation) the stresses which would result if the maximum pressure differential across the valve member was applied to the maximum area thereof when seated, so long as the valve member accommodates the maximum pressure differential acting across the smaller effecw tive area thereof defined by the inner periphery of the discharge port. Stated conversely, the valve would : have to be of much sturdier (and hence heavier) cons= truction if, when seated, the entire cross-sectional area thereof was subjected to the pressure differens ‘tials ‘thereacross. The relative angles of the valve member and seat also serve to cushion the impact of . the parts on closing, thereby contributing (along with light weight) to the reduction of noise and wear.

It should be noted that valve member 30 will oo 1b -

’ preferably have a thickness less than that of valve plate 12 in order to insure adequate sealing of sidewalls 32 with sidewalls 28 and to avoid a partial or complete annular groove being worn in sidewalls 32, which groove could possibly interfere with pro= per seating and/or sealing of valve member 30. Also, edge portion 60 will preferably be provided with a small radius or chamfer which operates to insure pro= per sealing even should valve member be shifted or . 10 cocked slightly during closing thereof. Additionale 1y, spring 42 preferatly has its ends squared and } ground and is of as large a diameter as possible rela tive to the diameter of valve member 30 so as to place the biasing force exerted thereby closely adjacent : 15 the sealing sidewalls 32 and to aid in preventing a shifting, tilting or other dislocation of valve mem=

Co per 30 during operation thereofe while the present invention has been described with reference to FIGS. 1 through 4 utilizing a reeds type suction valve, it is also well suited for use with a conventional ring-type suction valve such as is shown in the embodiment indicated generally at 6h in FIG. 5e Valve assembly 64 includes a valve plate 66 having a relatively large irregularly shaped gene~- rally annular recessed portion 68 defining a suction plenum in the lower surface 70 thereof. A discharge opening 72 of frusto conical shape is also provided, being defined by a radially inwardly inclined or . beveled sidewall 74 extending between upper surface 76 and lower surface 70 of valve plate 66. Surface 78 of sidewall 74 provides a valve seat plate 66.

Surface 78 of sidewall 74 provides a valve seat for a discharge valve member 30' which is urged into sealing engagement therewith by gas pressure and a : 10 spring U4' extending between valve member 30' and a spring retainer 50! all of which are substantially identiéal to corresponding portions described above with reference to FIGS. 1 and U4.

A generally annular valve plate insert 80 is disposed within recess 68 through which fasteners 82 oe extend so as to secure valve assembly 64 to a cylinder housing 84. A plurality of spaced cutout areas or radially extending slots (not down) are provided through valve plate insert 8o so as to allow suction fluid flow between radically inner and outer sides thereof.

A second insert in the form of an annular ring 86 is also provided, being received in an annular notch 88 provided in radially inward edge of lower sure : face 90 of valve plate insert 80, and being provided ) w 16 = with a plurality of spaced radially inwardly extend-

C ing reinforcing ribs 92 extending into engagement with surface 94 of sidewall 74. This is best shown in FIG. 6, in which is shown in bottom plan a dife

S ferent version of the discharge valve, but with a ring~type suction valve of the same conatruction as the present embodiment.

The terminal end 96 of sidewall 74 is posi tioned in coplanar relationship with lower surface 70 of valve plate 66, lower surface 90 of valve plate ine sert 80 and lower surface 98 of annular ring 86. A suction reed valve member 100 in the form of an annular ’ ring sealingly engages lower surfaces 96 and 98 so as to prevent passage of fluid between insert ring 86 and surface 94 into compression chamber 102. A central opening 104 is provided in suction reed valve | : member 100 which ig arranged coaxially with discharge opening 72 so as to allow direct fluid communication : between compression chamber 102 and lower surface 34t . 20 of discharge valve member 30's As best seen with reference to FIG. 6, suction reed valve member 100. also has a pair of diametrically opposed radially outwardly extending tab portions 108 and 110, each i of which is provided with a suitable opening 112 ex- - tending therethrough. As seen in FIG. 5, tab portion

108 and 110 are received in respective notched porw

Co tions 114 and 116 of cylinder housing 84 with fasteners . 82 extending through openings 112 so as to retain suc- tion reed valve member 100 in operative relationship= thereto.

As the reciprocating piston (not shown) dise posed within compression chamber 102 moves away from valve assembly 64 during a suction stroke, the pres gure differential between compression chamber 102 and suction plenum 68 will cause suction reed valve member 100 to deflect inwardly with respect to com= pression chamber 102 thereby enabling fluid flow from suction plenum into compression chamber 102 through inlet passages 106. Because only tab portions 108 end 110 of suction reed valve member 100 extend outwardly beyond the sidewalls 118 of compression chamber 102, suction fluid will readily flow into chamber 102 between suction reed valve member 100 and both surfaces 98 and 96 around substantially the en~ tire inner and outer peripheries of suction valve member 100, Ag a compression stroke of the piston begins, suction valve 100 will be forced into sealing engagement with surfaces 96 and 98 and the discharge valve member will begin to operate in the manner des 28 cribed above with reference to FIGS. 1 through 4.

Thus, as a result of this concentric arrangement substantially the entire available surface area i ‘overlying compression chamber 102 is utilized for suction and dimcharge valving and porting, thereby allowing maximum fluid flow both into and out of compression chamber 102.

Referring now to FIGS. 6 and 7, another em- bodiment of the present invention is illustrated which allows for even further utilization of the valve plate surface area overlying the compression chamber by providing a second concentrically arranged dise charge port area. With the exception of the dis- charge valve member and spring retainer, the various elements and portions of the suction and discharge valve assembly 120 are substantially identical to the corresponding portions of valve assembly 64 “of

FIG. 5 and therefore the same numerals are employed to designate identical portions and further descrip tion thereof is believed unnecessarye :

A discharge valve member 122 is provided dia posed within discharge passage 72. Discharge valve member 122 is similar to discharge valve member 30, being preferably fabricated from a polymeric composi tion having the aforementioned characteristics and having a frusto conical shape including outwardly die verging sidewalls 124, a lower surface 126, and an upper surface 128. However, in this embodiment valve member 122 also is provided with a centrally located generally frusto conically-shaped opening 130 defined by upwardly converging sidewalls 132.

A frusto conical disc member 134 having upwardly converging sidewalls 136 is also provided which is secured to and supported by a cylindrical stud member 138. Stud member 138 has an upper threaded portion 140 which extends through a threaded opening 142 pro vided in a spring retainer member 144 and cooperates : therewith to enable & lower surface 146 of disc mem= ber 134 to be adjusted into substantially coplanar relationship with lower surfaces 70 and 126 of valve i 15 plate 66 and discharge valve member 122 respectively,

Retainer member 144 also serves to limit opening move= ment of valve member 122.

As previously mentioned with regard to dis= charge valve member 30, a eenical sidewall 124 of dis- charge valve member 122 is preferably formed with an included angle (when unstressed) greater than the in- “cluded angle of the cone of sidewall 78. In like manner and for the same reasons, the included angle of conical sidewall 132 is greater (when unstressed) than the included angle of the cone of sidewall 136.

The operation of valve assembly 120 is } substantially the same as that of valve assembly 64 described above except that as discharge valve member 122 is caused to move upwardly, compressed fluid will be able to exhaust between both sidewalls 78 and 124 and between sidewalls 132 and 136. This arrangement thereby offers substantially increased discharge flow rates to be achieved within the re=- latively restricted head area for a given cylinder size by providing means whereby the discharge port area is substantially increased. On the other hand, this arrangement is harder to manufacture because of the close tolerances required between the two separate seats in order to get a good seal,

FIG. 8 illustrates a valve assembly 6 also in accordance with the present invention employing the discharge valve arrangement of FIG. 6 in con junction with a reed~-type suction valve of the type . described with reference to the embodiment of FIGS, 29 1 through 4. Accordingly, as the elements employed in this embodiment and the operation thereof are substantially identical to corresponding elements of

FIGS. 1 through U4 and 6, like portions have been in- dicated by like numerads double primed and further description: thereof is believed unnecessarye “?2l =

FIG. 9 illustrates an alternative embodiment of the present invention, indicated generally at 148, in which the additional porting is provided over that of the embodiment of FIGS. 1=5. Valve assembly 148 comprises a valve plate 150 having a conventional reed-type suction valve member 152 engaging the lower surface 154 thereof and a frusto conical discharge opening defined by upwardly diverging sidewalls 158 extending therethrough, all of which is substantially .

identical to that described with reference to FIGS. 1 through 5 above. i In this embodiment, however, a two-piece dis-

charge valve assembly is provided comprising a first frusto conical discharge valve member 160 having up~ wardly diverging sidewalls 162 adapted to sealingly engage sidewalls 158, an annular recess 164 provided in upper surface 166 thereof, and a centrally disposed fursto conical shaped opening defined by sidewalls 168 provided within recess 164. A second relatively move able frusto conical shaped discharge valve member 170 is provided having upwardly diverging sidewalls 172 adapted to sealingly engage sidewalls 168. Discharge valve member 170 has a recess 174 provided in upper surface 176 thereof which is adapted to receive one end of a biasing spring member 178 the other end of which engages a shoulder 180 provided on depending ) protrusion 182 of spring retainer 184, A second spring biasing member 186 has one end received in recess 164 of discharge valve member 160 and the other end engaging an annular recess 188 surrounding . protrusion 182 of spring retainer 184. Thus, spring ) biasing members 178 and 186 can operate independently to bias respective discharge valve members 170 and 160 into closed sealing engagement. spring retainer 184 may also have stop means in the form of an an- hular shoulder 190 which is positioned to engage upper. surface 166 of discharge valve member 160 while allow= ing continued upward movement of discharge valve member 1704

As is apparent, the relative sequence of open= ing of discharge valve members 160 and 170 may be easily selected by merely selecting the desired res= i pective spring characteristics, using standard cri= : teria. Both discharge valve members 160 and 170 preferably are fabricated from a suitable polymeric composition having the aforementioned characteristices have a thickness sufficient to provide the necessary strength but jess than the thickness of valve plate : 150, and have both conical valve seats having included angles which are greater (when unstressed) than the included angles of the respective valve seat sgidew walls. Further, the relative diameters of discharge valve members 160 and 170 will be such as to provide a substantially planar lower surface with surface 154 of valve plate 150.

With respect to the relative angles of incline : of the respective valve members and valve seats, applicant has obtained excellent test results with valve members having an unstressed sidewalls angle with respect to the axis of the valve seat or discharge passageway equal to approximately 47° (an included angle of 94°), with a corresponding valve seat angle of 45° (an included angle of 90°). These approximate relative angles apply to all of the disclosed embodi- ments of the invention, regardless of whether the valve member/valve seat interface is on the outside : periphery of the valve member or on the inside peri- phery of the valve member.

The significant performance improvements obe tained using the aforedeacribed preferred embodiment of the discharge valve (when substituted for existing discharge valves in current refrigeration compressors), ’ are also believed to be obtainable using other than polymeric materials. For example, in FIGS. 10«l5, there are illustrated several different lightweight oy “2h.

designs in which the valve member is formed from metal, and which are believed to also provide the advantages of the present invention, In all of these embodiments the valve plate is indicated at 212, the discharge port or passageway at 218, the frusto coni= ] cal valve seat at 228 and the helical compression spring at 2ih.

In FIG. 10 the valve member, indicated general- : ly at 230, is formed, such as by stamping from sheet metal, into the frusto conical form illustrated, have ing a generally flat centered disc portion 232 and up= wardly and outwardly extending conical side walls 23k, the outside surfaces of which sealingly engage valve geat 228 in exactly the same manner as those of the previously described valve members, Valve member 230 js contoured so that spring 24k will engage same at approximately the jntersections of portions 232 and 234, The embodiment of FIG. 11 is generally similar to that of FIG. 10 with the valve member, indicated at 246, also being stamped or similarly formed out of } ' sheet metal, but is provided with an upstanding outer peripheral flange 248 defining an internal shoulder for engaging and locating spring 244, FIG. 12 illustrates a generally gimilar valve member, indicated at 250 which differs from the preceding embodiment in that a definite annular pocket 252, having both bottom and side walls, is defined adjacent the outer peri- phery of the valve member for positioning and engag=- ing spring 244. The embodiment of FIG. 13 comprises | a valve member 254 which is essentially the same as that illustrated in FIG. 12 but is contoured or re- lieved to minimize the weight thereof. As can be seen, the metal of centered disc portion 232 is in . } great part substantially thinner, reinforcing being provided by integral ribs 256 and 258. The embodi- ments of FIGS. 12 and 13 may be formed by cold head- . ing. Other manufacturing techniques, such as casting, y may be applicable to any of the metal embodiments, as will be appreciated by one skilled in the art. In all of the above embodiments it is envisioned that the valve member will be formed out of a single piece of metal, such as steel, bronze, aluminum, or the like.

It is envisioned that a valve member embody ing the principles of the present invention may also be fabricated in composite form in the manner illus~ trated in FIGS. 14 and 15. In both of these figures the valve member itself, indicated at 260, ie subs- tantially the same as that shown in FIG. 10, although of slightly lesser gauge, with stiffening and strength »

being provided by a thickened or filled center sec- tion 262 formed of an-extremely lightweight rigid material (such as, for example, rigid foam, metal hoenycomb, or the like) securely bonded to valve member 260 and provided with a suitable reinforcing and protecting sheath 264 bonded to the opposite sur : face thereof and rigidly affixed to the inside sur=~ face of valve member 260, such as by brazing. Center section 262 interconnects valve member 260 to sheath 264 so that they act as a single beam. Sheath 26k and member 260 may be formed of any of the aforedes- cribed metals, and preferably sheath 264 defines an annular recess 266 to locate and engage spring 24h,

In all of the embodiments illustrated in FIGS. 10 through 15 the respective angles of the valve seats and the outer surface of side walls 234 are identical to those described in the preceding embodiments, and " . the thickness of the side wall portion 234 is chosen (for the metal used) to provide as light a weight as possible, as well as the compliance or resilience necessary to permit the valve member to close and seal without permanent deformation. Similarly, center . disc portion 232 is formed as light as possible but of a sufficient thickness and strength for the mate rial used (in combination with center stiffening / oo - 27 -

section 262 where applicable) to provide a subs- tantially flat flush surface (i.e., no excessive : distortion or permanent deformation) at the top of . the cylinder chamber when fully closed and ‘subjected 5 . to the maximum pressure differentials normally enw countered, the same as in the case of the preceding embodiments. In all of the embodiments formed from metal, the resulting valve member, whether it be of unitary construction or of composite construction, is extremely light weight compared to known conical valves and is believed to be capable of providing the advantages of the previously described polymerie valve eleménts, particularly those disclosed in FIGS. 1 through 5. Ideally, the valve members of FIGS. 10 through 15 will be formed in such a way and with such geometry and of a material which will provide the characteristics achieved by applicant with the afore« described preferred form of the valve members Al= though metal valve members may be slightly noisier than polymeric valves, the progressive engagement of valve member and valve seat due to the relative angle thereof is believed to provide some degree of noise attenuations

Gne of the advantages of the valve of the present invention is ‘that, unlike reed valves, the weight or mass of the valve is independent of the oo force of the return spring (i.e., spring bl, Whe, bh, etc.). This makes it possible to choose the spring to optimize valve frequency (to achieve closure as close to top dead center as possible) and/or valve preload (i.e., the.initial sealing i force in absence of a pressure differential). Be cause one of the more important functions of the re=- turn spring is to stabilize the valve as it is cycled in response to changing pressure differentials, the spring is preferably of as large a diameter as is feasible. ’ | In all embodiments of the invention the valve plate is utilized in the compressor in a conventional . 15 manner, and the pistons, cylinders, suction valves, manifolds, etc. are conventional. If desired, the top of the piston may be very slightly contoured to £ill the small, thin space in the center of the suce tion valve when the piston is at top dead center, thereby further reducing reexpansion volume. Alsoy the bridges may have three legs instead of two in Co order to increase flow area.

While it will bespparent that the preferred ’ embodiments of the invention disclosed are well cal« s 29 = .

culated to provide the advantages and features above stated, it will be appreciated that the ine vention is susceptible to modification, variation and change without departing from the proper scope . 5 or fair meaning of the subjoined claims, - 30 m

Claims (32)

I CLAIM:

1. A discharge valve element for use in a gas compressor having a valve plate equipped with an inner surface in part defining a compression " chamber, a discharge port and valve seat extending through said valve plate and diverging outwardly from said inner surface, said valve element having an outwardly diverging seating surface and being formed from sheet metal of a thickness rendering it capable of distorting to conform to the valve seat with an inner surface of said valve element lying : substantially in the plane of said inner surface of said valve plate when the discharge valve element is closed, said distortion resulting in a reactive - force tending to unseat said discharge valve elemento

2. A discharge valve element as claimed in Claim 1 further comprising stiffening means formed of a relatively light-weight rigid material and affixed to a generally central portion of said valve element,

3. A discharge valve element as claimed in claim 1, wherein said seating surface is disposed on an ogtwardly diverging peripheral portion of said valve element, said peripheral portion being relative~ 1y unsupported in a’direction generally perpendicular . - 31 w= to said outward direction. .

4, A discharge valve element as claimed in Claim 1, wherein said sheet metal is sufficient=- ly flexible and resilient to be capable of said distortion to conform to the valve seat without permanent deformation. .

5. A discharge valve element as claimed in Claim 1, wherein said seating surface diverges outw wardly at a slightly greater included angle when unstressed than the included angle of said outwardly diverging valve seat so that a larger diameter portion of said seating surface engages the valve seat first during closure,, whereby complete seating occurs inw= “" cident to said distortion of said valve element, said distortion resulting in a reactive force tending to unseat said discharge valve element.

6. A discharge valve element as claimed in Claim 1, wherein said valve seat and said seating surface are both generally frusto-conical in shape.

7. A discharge valve element for use in a gas compressor, said valve element being formed from flexible and resilient sheet metal and having a gene~ rally flat portion thereon, the thickness of said flat portion being substantially less than the thickness of the remainder of said valve element, said flat portion being reinforced by at least one integral . rib member thereon. }

8. A discharge valve element as claimed in Claim 7, wherein said gas compressor includes a valve plate equipped with an outwardly diverging valve seat, said discharge valve element including a peripheral portion extending generally outwardly from said flat portion, said peripheral portion having an outwardly diverging seating surface thereon, said sheet metal being sufficiently flexible and resilient so that said seating surface is capable of conforming to said valve seat,

9. A discharge valve element for use in a gas compressor, said valve element being formed from flexible and resilient sheet metal and having a peri- pheral edge portion thereon, at least a portion of said valve element being reinforced by stiffening means formed of a relatively lightweight rigid mates - rial affixed thereto, said valve element further ine cluding a sheath member partially enclosing said lightweight rigid material, said sheath member fure ther being affixed to said peripheral edge portion, and said Lightweight rigid material being substantial- ly sandwiched between’ and affixed to both said sheath member and said valve element so that the composite structure of said sheath member, said lightweight rigid material and said valve element act as a single beam member, ’

10. A discharge valve element for use in a gas compressor, said valve element being formed from Co flexible and resilient sheet metal and having a genew rally flat portion thereon, at least said generally flat portion being reinforced by stiffening means formed of a relatively lightweight rigid material affixed thereto, said valve element further including a sheath member partially enclosing said lightweight rigid material, said sheath member further being } affixed to said valve element, and said lightweight rigid material being substantially sandwiched between and affixed to both said sheath member and said flat portion so that the composite structure of said sheath mémber, said lightweight rigid material and said valve element act as a single beam members. -

11. An improved préssure responsive valve assembly comprisings a valve plate having an inner surface in part defining a compression chamber; } a discharge valve seat opening extending through said valve plate, said valve seat opening being defined by an outwardly diverging conical sidew walls : . a frusto conical discharge valve member dise posed within said opening and having a peri pheral edge surface of conical configuration adapted to sealingly engage said sidewall of said valve seat opening, said discharge valve member being formed of sheet material of a thickness rendering it capable of resilient- . ly distorting to conform to said valve seat, : said conical peripheral edge surface of said : discharge valve member having an included : angle when undistorted which is greater than the included angle of said conical sidewall of said valve seat opening; and spring nesns guiding and biasing said valve : member toward said valve seat opening, said spring means directly engaging said valve member on a portion thereof facing away from said compression chamber and oo constituting the sole guide for said valve member as it moves toward and away from said valve seat openings

12. A valve assembly as claimed in Claim 11,

wherein said valve member has an inner surface which is substantially flush with said inner sure : face of said valve plate when said valve member is seated.

13. A valve assembly as claimed in Claim : 11, wherein said valve member is compliant enough to provide a surface-to-surface seal under normal close . ing pressures without permanent deformation.

14, A valve assembly as claimed in Claim 11, further comprising means limiting movement of said ; valve member with pespect to said valve plate in a valve opening direction. :

15, A valve assembly as claimed in Claim 11, ” further comprising means defining suction passages in said valve plate and a suction valve member engaging . said inner surface of said valve plate to alternate~ ' ly allow and prevent fluid flow through said suction passageso

16. A valve assembly as claimed in Claim 15; wherein said suction valve member is a reed having a central opening therethrough aligned with said discharge valve seat opening. . 17. A valve, assembly as claimed in Claim 11,

wherein said undistorted included angle of said peripheral edge surface is approximately 94° and said included angle of said conical sidewall of said valve seat opening is approximately 90°,

18. A valve assembly as claimed in Claim 11, wherein said valve member is disposed wholly between the planes of said inner and outer surfaces of said valve plate when fully closed.

19. In combination with a gas compressor an improved pressure responsive valve assembly, come ¢ prising: a valve plate having an inner surface in part defining a compression chamber; Lo : a discharge port extending through said valve plate; : means defining a valve seat of circular cross~ section in said port, said valve seat being of increasing diameter in a direction away from said compression chamber; and a discharge valve member formed of a relatively compliant sheet metal composition disposed within said port such that the inner surface of said discharge valve member lies subse tantially in the plane of said inner surface of said valve plate when the discharge valve

. is closed, said discharge valve member having a To peripheral edge surface adapted to sealingly engage said valve seat, said peripheral edge surface of said discharge valve member and said valve seat opening being configured so that a larger diameter portion of said edge surface engages said valve seat first during closure, whereby complete seating occurs incident to distortion of said discharge valve mem ber, said distortion resulting in a reactive force tending to unseat said discharge valve member.

20. The combination of Claim 19, wherein said valve seat and said peripheral edge surface are : conical, the included angle of said edge surface be- ’ ing slightly greater than that of the mating valve seat to insure that an edge surface portion of a larger digmeter engages the valve seat first during closure, whereby complete weating occurs incident to distore tion of the valve.

21. The combination of Claim 19, wherein said composition is of sufficient compliance to pro= vide sealing without permanent deformation of said valve element. } 22. An improved valve assembly for a gas com- pressor comprising:

a valve plate having a substantially flat , inner surface in part defining a compression chamber; a discharge valve seat opening extending through said valve plate, said valve seat opening being defined by an outwardly di- verging sidewall} a resilient discharge valve member disposed within said opening and having a peripheral oo edge surface of outwardly diverging confie guration adapted to sealingly engage said sidewall of said valve geat, said valve mem= ber being formed of sheet metal of a thicke } ness rendering it capable of deformation to conform to said valve seat, the inndr surface of said discharge valve member lying substantially in the plane of . said inner surface of said valve plate when the discharge valve is closed, at least a portion of said discharge valve be= ing resiliently deformed when in said closed position’ such that said deformation results in a reactive force tending to unseat paid discharge valve members; a suction gas opening extending through sald valve plate, . said suction gam opening being generally annular in shape and surrounding said discharge valve seat opening; and an annular suction reed valve disposed in said cylinder chamber and surrounding said , discharge valve seat opening to control the flow of suttion gas through said suction gas opening, the upper surface of said suction : : reed valve normally engaging said inner sure face of said valve plate.

23+. An improved pressure responsive valve asw sembly for a gas compressor comprising: a valve plate adapted to be disposed in overe lying relationship with respect to a cylinder chamber and having an inner surface in part : defining a compression chamber within said cylinder chambers a discharge port extending through said valve plate; . means defining a valve seat of circular cross= section in said port, said valve seat being of increasing diameter in a direction away from said cylinder chamber; . wli0 = - : :

a discharge valve member formed of a relative~ . ly compliant sheet metal material disposed within sald opening and having a peripheral : edge surface forming a substantially frusto-~ conical valving surface thereon adapted to sealingly engage said valve seat, said peri=- pheral edge surface of said discharge valve member and said valve seat opening being con=- figured so that all points on said valving surface lie on the same cone and the largest diameter portion of said valving surface en~ gages maid valve seat first during closure, whereby complete seating occurs incident to elastic distortion and stressing of said dis~ ¥ charge valve member, said elastic distortion and stressing resulting in a residual re-: active force tending to unseat said valve member; and E ‘ spring means for exerting a biasing force on said valve member in a direction toward said valve seat, said residual reactive force be= ing greater than the opposing biasing force exerted by said spring means. . 24, A valve assembly as claimed in Claim 23 wherein said valve seat and said peripheral edge : - surface are conical in configuration.

25. In a reciprocating refrigerant piston= . type gas compressor having means defining a cyline . drical bore, piston means reciprocably movably with - ! in said bore and means forming a top closure plate } : for said cylindrical bore, the improvement comprising a pressure responsive discharge valve assembly ine cluding: means in said top closure plate forming a valve opening having a circular crosse= ; section sloping seat or outwardly increas ing diameter in a direction away from the cylinder bore thereby forming an opening which is smaller in cross-sectional area on the cylinder side of said plate than on an opposite discharge side thereof; and a valve having a disc-shaped body formed of resiliently deformable sheet metal matew : rial received in said valve opening, said valve body having a peripheral valving surface of a substantially frusto-conical : configuration with all points on said valve ing surface lying on the same cone, said - 25 valving surface having a marginal edge - b2 = :

. . thereof proportioned to engage said seat in essentially line contact in the absence of differential pressure thereacross, said valve ‘ being resiliently deformable in response to a net pressure above said valve to move into area contact between said valving surface thereof and a corresponding surface of said Co seat accompanied by a reduction in the effec=- tive cross-sectional area of said valve body exposed to a pressure differential therew across, the resilient deformation of at least a pore tion of said valve body resulting in a residual reactive force thereon, said re- sidual reactive force thereby tending to cause said valve body to unseat from said : valve opening.

26. In combination with a gas compressor, an improved pressure responsive discharge valve asseml= ’ bly comprising: a valve plate having an jnner surface in part defining a compression chamber; a discharge valve seat opening extending oo through said valve plate, said valve seat . J opening being defined by an outwardly di- oo verging conical sidewall, the entirety of the operable surface of said sidewall being defined by a single cone and being formed of a single material; a frusto-conical discharge valve member dis- posed within said opening and having a perie pheral edge surface of conical configuration adapted to sealingly engage said sidewalls of said valve seat opening, the entirety of the operable portions of said conical peripheral "edge surface of said dis=~ charge valve member being formed of a single ' sheet metal material and defined by a single cone, and having an included angle when une: stressed which is greater than the included angle of said conical sidewall of said valve set opening; and : spring means guiding and biasing said valve member toward said valve seat opening, . said spring means directly engaging said valve member on a portion thereof facing away from said compression chamber and constitut~ ing a guide for said valve member as it noves toward and away from said valve seat : Lo Ca CN ~ bh oo opening,

27. An improved pressure responsive valve assembly for a gas compressor, comprising: a valve plate adapted to be disposed in over- lying relationship with respect to a cylinder chamber and having an inner surface in part defining a compression chamber within said cy- linder chambers; a discharge port extending through said valve plate; means defining a valve seat of circular crosses section in said port, said valve seat being of increasing diameter in a direction away : from said cylinder chamber; a discharge valve member disposed within said opening and having a peripheral edge surface adapted to sealingly engage said valve seat; © said peripheral edge surface of said dise charge valve member and said valve seat opening being configured so that the largest ; diameter portion of said edge surface en~ gages said valve seat first during closure, whereby complete seating occurs incident to distortion and stressing of said dime charge valve member; and

‘ . | bs

) : » spring means biasing said valve member toward said valve seat, the force exerted on the valve member in a direction away from ' said valve seat as a result of said valve member unstressing being greater that the opposing force said spring means applies . against said valve member when seated, said valve member being formed of a ree silient sheet metal materiale

28. In combination with a gas compressor an. improved pressure responsive valve assembly, comprise ings a valve plate having an inner surface in part defining a compression chamber; : 15 a discharge port extending through said valve plate; means defining a valve seat of circular Crosse , section in said port, said valve seat being of increasing diameter in a direction away from said compression chamber; a discharge valve nember formed of a relative ly compliant sheet metal composition die posed within said port such that the inner surface of said discharge valve member lies substantially in the plane of said inner oo - 46 = Co surface of said valve plate when the dis charge valve is closed, said discharge valve member having a generally flat portion and a peripheral edge portion intersecting said generally flat portion, said peripheral edge portion being adapted to sealingly engage said valve seat, said peripheral edge portion 6f said discharge valve member and said valve seat opening being €onfigured so that a larger ' 10 diameter portion of said edge portion engages said valve seat first during closure, whereby : complete seating occurs incident to distor- tion of said discharge valve member, said dis- tortion resulting in a reactive force tende ing to unseat said discharge valve member; and ’ spring means biasing said valve member towardx said valve seat opening, said spring means engaging said valve member generally at said : intersection of said flat portion and said peripheral edge portion. :

29. In combination with a gas compressor an improved pressure responsive valve assembly, compris : ing: a valve plate having an inner surface in part defining a compression chambers : a discharge port extending through said valve plate} means defining a valve seat of circular cross- section in said port, said valve seat being of increasing diameter in a direction away from said compression chamber; . a discharge valve member formed of a relatively compliant sheet metal composition disposed within said port such that the inner surface © of said discharge valve member lies subse tantially in the plane of said inner surface of said valve plate when the discharge valve is closed, said discharge valve member have ing a peripheral edge portion adapted to TL sealingly engage said valveseat, said peri . : pheral edge portion of said discharge valve member having an outer peripheral flange thereon, said peripheral flange and the ree mainder of said peripheral edge portion dew fining a shoulder therebetween, said perim pheral edge portion, and said valve seat opene ing being configured so that a larger dia= meter portion of said edge portion engages : 25 said valve seat first during closure, whereby complete seating occurs incident to dis= tortion of said discharge valve member, said distortion resulting in a reactive force } tending to unseat said discharge valve men ber; and spring means biasing ‘said valve member toward said valve seat opening, said spring means engaging said shoulder on said peripheral edge portion.

30, In combination with a gas compressor an improved pressure responsive valve assembly, comprise ing:

a valve plate having an inner surface in part defining a compression chamber;

a discharge port extending through said valve plate; means defining a valve seat of circular crossw section in said port, said valve seat being of increasing diameter in a direction away from said compression chamber;

a discharge valve member formed of a relatively compliant sheet metal composition disposed within said port such that the inner surface of said discharge valve member lies subs tantially in the plane of said inner surface of said valve plate when the discharge valve is closed, said discharge valve mem=- : ber having a peripheral edge portion adapted to sealingly engage said valve :

seat, said peripheral edge portion of said discharge valve member having a pocket formed on the inside surface thereof, said pooket having a bottom wall and a side wall, said ’ peripheral edge portion and said valve seat opening being configured so that a larger diameter portion of said edge portion engages said valve seat first during closure, where= by complete seating occurs incident to dis tortion of said discharge valve member, said distortion resulting in a reactive force tend- ing to unseat said discharge valve member; and : spring means biasing said valve member toward said valve seat opening, said spring means engaging said pocket on the inside surface of said peripheral edge portion.

31, In combination with a gas compressor an ‘ improved pressure responsive valve assembly, comprise ings a valve plate having an inner surface in part : defining a compression chamber; a discharge port extending through said valve plate; means defining a valve seat of circular cross section in said port, said valve seat being of increasing diameter in a direction away from said compression chamber} and a discharge valve member formed of a relative= . 10 ly compliant sheet metal composition diaw- } : posed within said port such that the inner surface of said discharge valve member lies substantially in the plane of said inner surface of said valve plate when the dis charge valve is closed, said discharge valve member having a peripheral edge surface i adapted to sealingly engage said valve seat, . said peripheral edge surface of said dise charge valve member and said valve seat openw ing being configured so that a larger dias meter portion of said edge surface engages : said valve seat first during closure, where=- by complete seating occurs incident to die tortion of said discharge valve member, said Co distortion resulting in a reactive force tending to unseat said discharge valve memw } ber; said discharge valve member having a generally flat portion thereon, the thick~ . ness of said flat portion being substantial=- ly less than the thickness of the remainder of said valve element, said flat portion be= ing reinforced by at least one integral rib member thereon,

32. In combination with g gas compressor an improved pressure responsive valve assembly, comprising: in a valve plate having an inner surface in part defining a compression chamber; a discharge port extending through said valve plate; means defining a valve seat of circular crosse section in said port, said valve seat being of increasing diameter in a direction away from said compression chamber; and ' a discharge valve member formed of a relatively compliant sheet metal composition disposed oo within said port such that the inner surface of said discharge valve member lies subse °° tantially in the plane of said inner surface of said valve plate when the discharge valve : 25 is closed, said discharge valve member having a peripheral edge portion adapted to seal~ ingly engage said valve seat, said perie pheral edge portion of said discharge valve member and said valve seat opening being configured so that a larger diameter por= tion of said edge portion engages said valve seat first during closure, whereby complete seating occurs incident to disteke tion of said discharge valve member, said distortion resulting in a reactive force ‘tending to unseat said discharge valve mem= ber, said discharge valve member being res inforced by stiffening means formed of a relatively lightweight rigid material } : iy 15 affixed thereto, said discharge valve mem= ber further including a sheath member partial=- : B ly enclosing said lightweight rigid material, said sheath member further veing affixed to said peripheral edge portion of discharge valve member, and said lightweight rigid material being substantially sandwiched - between and affixed to both said sheath meme ber and said discharge valve member so that the composite structure of said sheath mem=- . ber, said lightweight rigid material and

NE eo said discharge valve member act as a single SA beam member. :

33,. In combination with a gas compressor an improved pressure responsive valve assembly, come prising: } : } a valve plate having an inner surface in part defining a compression chamber; ‘ a discharge port extending through said valve - | } plate; means defining a valve seat of circular cross= section in said port, said valve seat being : of increasing diameter in a direction away a from said compression chamber; and . . a discharge valve member formed of a relatively compliant sheet metal composition disposed within sald port such that the inner surface , of said discharge valve member lies subs= tantially in the plane of said inner surface of said valve plate when the discharge valve | is closed, sald discharge valve member having : ‘a peripheral edge portion adapted to sealing- oo ly engage said valve seat, said peripheral edge portion of said discharge valve member i and said valve seat opening being configured so that a larger diameter portion of said . - sh -

edge portion engages said valve seat first during closure whereby complete seating occurs incident to distortion of said dise charge valve member, said distortion re= sulting in a reactive force tending to une seat said discharge valve mémber, said dig=- charge valve member having a generally flat portion thereon, at least said flat portion being reinforced by stiffening means formed of a relatively lightweight rigid material affixed thereto said discharge valve member further including a sheath member partially enclosing said lightweight rigid material, said sheath member further being affixed to said discharge valve member, and said light weight rigid material being substantially : sandwiched between and affixed to both said " gheath member and said flat portion so that the composite structure of said sHeath meme ber, said lightweight rigid material and said discharge valve member act as a single beam member. . __ROBERT W.

KING , Inventor - 55 = ‘ - a