US2241931A - potter - Google Patents

Description

May 13, 1941. T. l. POTTER THERMOSENSITIVE EXPANSION VALVE 2 Sheets-Sheet l Filed March 13, 1936 w w .mwN

@E wh lPatented May 13, 194i 'antan T QFFECE THERMOSENSITIVE EXPANSION VALVE Thomas I. Potter, Bualo, N. Y., assigner to Refrigeration Patents Corporation, Bualo, N. Y., a corporation of New York Application March 13, 1936, Serial No. 68,770

(Cl. (i2-8) 24 Claims.

The present invention relates to expansion valves for refrigerating orcooling systems and has for an object to provide an expansion valve which includes thermosensitive means for controlling the passage of refrigerant uids therethrough.

An object of the invention is to provide an expansion valve having an orice which will automatically expand and contract to take care of variations in the heat load on the refrigerating system. An advantage of this arrangement is that in a compressor-condenser-expander system the compressor may run continuously instead of intermittently, as has been heretofore the practice, and the control of the cooling or refrigerating effect may be maintained within predetermined limits by automatic adjustment of the expansion Valve.

Another object of my invention is to provide an expansion valve which will completely cut off the flow of the refrigerant when for any reason the compressor is stopped, thus preventing flooding of the system with liquid refrigerant.

Still another object of my invention is to provide means for trapping some of the liquid refrigerant in the expansion valve on the low pressure side of the valve so as to prime the valve when starting up the compressor after it has been stopped. In other words, when the valve has been warmed sufciently to completely close the orice and the compressor is then started the evaporation of the trapped liquid will serve to cool the expansion valve sufliciently to open the orice.

Other objects and advantages of my invention will appear in the following description of certain embodiments thereof and thereafter the novelty and scope of the invention will be pointed v out in the claims.

In the accompanying drawings;

Figure 1 is a View in longitudinal section of one form of my invention comprising an expansion valve-that is sensitive to temperature conditions immediately surrounding the same;

Fig 2 is a view in longitudinal section of another embodiment of my invention in which the liquid refrigerant jackets one of the expansion elements of the valve;

Fig. 3 is a Viewl in longitudinal section of a jacketed type of expansion valve in which fluid from the discharge end of Yan evaporator or cooling coil may be passed through the jacket to control the extent of openingof the expansion oriiice of thevalve;

Fig. 4 is a diagrammatic view of a. household ref rigerating system, in which the expansion valve shown in Fig. 1 may be incorporated; and Fig. 5 l

is` a diagrammatic view of a similar system in which the valve shown in Fig. 3 may be incorporated.

The expansion Valve shown in Fig. 1 comprises a tubular casing Ml formed exteriorly with annular anges il to increase its heat-absorbing area. One end of the tubular casing is closed by a plug l2 having a bore i3 therethrough. A high-pressure refrigerant line M is c0up1ed`to 'this plug. A gasket l5 serves to seal the joint between the plug and the casing. At the inner end of the plug there is a. conical valve seat .for a needle valve I6 carried on the end of a rod Il. 'I'his rod extends axially through the casing I0 and at its opposite end is threaded into a bore l9fformed in an adjusting head 20. This adjusting head is, in turn, threaded into a tubular plug 2l closing the adjacent end of the tubular casing lll. 'A gasket 22 serves to provide a tight seal between the plug and the casing. The plug 2| is formed with a reduced inwardly directed extension 23, which is longitudinally slotted toreceive a pin- 24 transversely mounted in the rod I1. The parts are so arranged that, as the head 20 is turned inone direction or the other, it will advance the needle valve I6 toward or withdraw it from its seat, the needle valve being prevented from turning by the pin 24 engaging the slotted extension 23.` 'Ihe pitch of the threads on the rod I1 has a differential relation to the pitch of the threads on the exterior of the plug 20, whereby a fine micrometer adjustment of the needle Avalve I6 may be obtained. Because the rod is adjustable in the bore i9 of the head 20, means are provided for venting the inner end of said bore. To this end the rod I1 has an axial bore open to the bore I9, communicating through a lateral port 25 with the expansion chamber or annular space 26 between the rod I1 and the casing Ill.4

In order to prevent leakage along the threaded surface of the adjusting head 20, a packing box.is provided. In other words, the bore of plug 2| is enlarged to receive packing material 21 which is compressed about the adjusting head 20 by a gland 28 threaded thereon. A cap 29 is tted over the'gland 28 and is screwed upon a threaded extension of the plug 2l. A gasket 30 serves to seal the joint between the cap and the plug.

The chamber I0 has an outlet port 3l adjacent the plug 2l. A nipple 32 is threaded into this port and coupled to this nippleisa low pressure or expansion line 33. y

The casing I0 ofthe expansion valve is preferably iormed of steel while the rod l1 which carries the needle valve, is preferably formed of brass s o that there will be a differential expansion and contraction'of these two elements under varyexpansion valve is cooled below a predetermined.

temperature, the valve I6 will be in closed position. In order to start operations, there must'l be a certain amount of lliquid refrigerant in the expansion space 26. Initially the expansion valve may be primed by operating the adjusting head 20 to crack open the valve, but under service conditions if the compressor should be stopped, enough refrigerant will Vaccumulate in theexpansion line, before the expansion valve is warmed suiciently to close, to insure the trapping of a small amount of liquid in the expansion chamber.

In Fig 4 is disclosed a household refrigerating system in which the valve shown in' Fig. 1 may be incorporated. Any suitable form of cabinet |20 provided with a cooling chamber |2| and a mae chinery compartment or space |22 may beemployed. The system includes any form of com- A pressor |23, any suitable form of condensor and liquid reservoir |24 and any suitableform of evaporator |25. The reservoir is connected by the high pressure line I4 to the inlet of the expansion valve indicated at I0, the outlet of the expansion valve being connected by the line 33 to 'one end of the evaporator |25,7 the other end of which is connected by the line |26 to the low side of the compressor |23.

In use the expansion valve is, located in the room or chamber that is being cooled, so as to control temperature conditions therein. Let us assume .that the compressor of the refrigerating system controlled by the expansion valve is being started up after a shut-downof sufiicient duration to close the expansion orice of the expansion valve, but that a small amount of liquid refrigerant has been trapped -in the expansion chamber. The suction produced by the compressor lowers the boiling point in the expansion line sufficiently to evaporate the trapped liquid, thereby abstracting heat from the casing and rod while the casing is kept relatively warm by lits greater .heat capacity and by the ambient heat fiowing in through the flanges. As a result -the rod contracts to a much greater degree than does the casing l0, withdrawing valve I6 from its seat and starting the fiow'= of refrigerant through the expansion valve. This differential contraction is further accentuated by the greater coeiiicient of contraction of the brass rod than of the steel casing. The parts are so proportioned that the expansion orifice will open `wide enough to admit a predetermined maximum of refrigerant. However, as the temperature of the cooling chamber is gradually lowered, the casing will contract correspondingly and gradually reduce the expansion orifice. This contraction will continue until the quantity of refrigerant admittedis just suiiicient to take care ofv the heat load on the expansion line, when abalance will be, struck.. Thereafter, any variation in thelheat load will result in a corresponding change in the expansion orifice, For instance, if the expansion valve islocated in the food chamber of a household refrigerator, every time the'door of the chamber is opened or every time relatively warm -food is introduced into the chamber, there will bea rise" extra heat has been carried olf, when the casing will again contract to establish the normal working balance.

Under running conditions the length of the vvalve stem remains substantially constant al.

though there will be some uctuation, and variation of the expansion orifice will result in variation y of pressure in the expansion line with attendant variation of boiling point of the refrigerant. However, after the expansion orifice has been opened by cooling of rod substantially to the .temperature of the expanding refrigerant further adjustment of the orifice, as long as the compressor is operating, will be controlled mainly by a -oontractionand expansion of the casing I0 which directly refiects ambient temperature conditions. One of the reasons formaking the valve stem of a metal having ahigher coefiicient of -expansion than that of the valve casing, is to prevent the orice from being throttled too much orentirely closing as the ambient temperature approaches the temperature of the expanding refrigerant. Manifestly, if the casing and the valve stem had .thesame coeflicient of expansion the orifice would be closed whenever the casing and stem were of the same temperature no matter what that temperature was, 'and if the casing cooled down to the temperature of the'refrigerant in chamber 26 the valve orifice would entirely close. This, howeverLcannot occur where the stem has a higher coefficient of contraction than the casing. The orice must remain open whilef the compressor is running. When the compressor is stopped and the expansion valve is allowed to Nefficient of expansion will overtake the casingwarm up, b oth the casing and the valve stem will expand, but the latter because of its higher coand close the expansion orifice at a predetermined temperature, not, however, before enough refrig- But the latter is immediately chilled erant has been admitted to the expansion line to build-up a pressure therein sufficient to trap and maintain some of'the refrigerant in' liquid form y in chamber 26. The expansion valve is the coldest` point in the expansion line and the liquid refrigerant in chamber 26 will be the last tol vaporize. Preferably the expansionvalve is located at a low point in the expansion line'and this line leads out of the upper side of chamber 26, as shown inI Fig. 1, so'that there will'be no danger of draining out the Aliquid trapped in said chamber. It is the compressor which, by lowering the boiling point in the expansion line, causes the expansion orifice to open and keep open. Hence, when the comi pressor is shut down the orifice will close', preventing ii'ooding of. the expansion line, s ov that on restarting the compressor there will vbe no slugs of liquid drawn therein which might cause .the compressor damage.

The expansion valve shown in Fig, 2 differs from vthat'shown in Fig. 1, in that the incoming liquid refrigerant jackets the expansion chamber, being interposed between the latter and the outside casing of the valve. The valve proper or closure member islcarried by said casing while the seat for the closure member is carried Aby atube in which the expansion chamber is formed. The differential expansion and contraction of the tube and casing control the size of the expansion orifice The outer shell or casing 39 of lthevalve en: closes an intake chamber- 40. Opening through the Wall of th'e casing into this chamber near one end thereof vis an inlet port 4|. Screwed into this port is a nipple 42 to which is coupled the high pressure refrigerant supply line 43. The chamber 4U is closed at the end adjacent the inlet port by a plug 44 screwed into the casing. The plug has an enlarged head portion which overlaps the end of the casing, and between said end and said head a gasket 45 is introduced to provide a gas-tight seal. The plug has a reduced outer extension 46 which is externally threaded, and an axial bore 41 extends through the plug and said extension. An outlet pipe 48 may be connected by a coupling 49 to the extension 46 and in communication with said bore.

The bore of the plug is enlarged at its inner end and has a threaded portion into which is screwed the stem 56 of a tubular holder 5 l Tightly screwed into this holder is an inner tube 53 which is disposed axially in the chamber 40. The opposite end of the tube 53 is provided with a tubular enlargement 54 having a conical orifice 55. 'This orifice forms a seat for a conical valve or closure member 56 carried by a valve-head 51. The valve-head is fitted to slide within the casing 39. To prevent the valve-head from turning it is formed with a keyway 58 which is engaged by the end of a screw 59 threaded through the side wall of the tubular casing 39.

The valve head 51 is` formed with a stem 66 which is threaded into an adjusting plug 6I and said plug in turn has threaded engagement with the casing 39. The pitch of the threads on the outer surface of the plug 6l has a differential relation to that of the threads on the stem 6I) such that upon turning the plug 6I a micrometer adjustment of the needle valve 56 will be obtained. The adjusting plug may be formed with a transverse slot 62 to receive a screw-driver for eiecting the desired adjustment of the valve 55. A screw plug 63 closes the adjacent end of the tubular casing 39, and is formed with a headed portion overlapping the end of the casing, so that a gasket 64 may b e introduced between the head and the casing to provide a gas tight seal. The operation of this expansion valve is similar to that shown in Fig. 1 and maybe connected in a refrigerating system in the same manner as the valve shown in Fig. 1 as illustrated in Fig. 4. Starting from the closed position shown in Fig. 2, with some liquid refrigerant trapped in the tube 53, when the compressor is operated and lowers the pressure in tube 53, the liquidtherein boils, chilling and contracting the tube and withdrawing the valve seat member 54 from the closure member 56, thereby opening the expansion orice 55.V The casing 39-is protected from the chilling effect of the expanding refrigerant by the intervening jacket of liquid refrigerant filling chamber 40. The inlet pipe 43 is of copper or other metal of high thermal conductivity so that the liquid refrigerant is chilled as it is being led through the chamber that is being cooled Thus, the liquid refrigerant in chamber 40 is at approximately the same temperature as that of the air surrounding the expansion valve. Because of the far greater heat absorbing area of the outer casing 39 than of the inner tube 53 the liquid refrigerant in chamber 40 will directly reflect ambient p valve, the casing 39 contracts, gradually closing the expansion orifice and reducing the refrigerating effect until a balance is reached.` The expansion valve seeks to maintain the balance, autotube 53 could therefore be made of the same metal. However, I find it preferable to use a metal of higher coefficient of expansion and contraction for the inner tube 53 so as to increase the relative movement of the tube and casing under varying temperature conditions. It will be understood that the parts are so designed and the expansion valve is so located in the refrigerant e system that when the compressor is stopped,'be-

fore the expansion orifice is completely closed a certain amount of liquid will be trapped in tube 53, so that the orifice may bev automatically reopened when th-e compressor is started up again.

The preferred form of 'my invention is illustrated in Fig. 3. This form of expansion valve when used in a household refrigerating system may be connected in the system as disclosed in Fig. 5, the corresponding parts in Figs. 3 and 5 bearing the same reference characters. In this device there is an outer tube 10, an intermediate tube 1I and an inner tube 12 all annularly spaced and preferably concentrically mounted so that a chamber 13 is provided between tubes 10 and 1i and an intermediate chamber 1li-is provided between. tubes 1i and .12. Within the tube 12 there is the expansion chamber 15. Mounted on opposite ends of the outer tube 10 are collars 16 and p 11 respectively, in which the intermediate tube 1l is threaded, thus closing opposite ends of the outer chamber 13. A port 18 in the collar 11 communicates with one end of the outer chamber 13 and is provided with means for coupling 'an inlet tube 19 thereto. In the collar 16 there is an outlet port for the outer chamber 13 provided with means for coupling an outlet tube 8l thereto. The intermediate chamber 14 is closed at one end by a fiange plate 83 secured to the outer face of the collar 11. This flange plate is formed with a tubular projection 84 in the bore 85 of which is threaded the adjacent end of the tube 12. A gasket 86 between the ange plate 8 3 and the collar 11 serves to provide a gas-tight seal. 'I'he opposite end of the chamber 14 is closed by ,a anged vtubular fitting 88 suitably secured to the outer face of the collar 16 with a gasket 69 therebetween to provide a gas-tight seal.

The free end of the tube 12, that is theleft hand end, as viewed in Fig. 3, is provided with a collar 9| which has a sliding t in the tube 1I. The purpose of this is to give support to the free end ofthe tube 12. However, to prevent the collar from plugging the tube 1I it is fluted to form passages 92. In this way free communication is provided between the body of the chamber 14 and the extremity thereof beyond the collar 9 I. Refrigerant is introduced into the intermediatechamber 14 through a. port 93 at the right hand end of the device, as shown in Fig. 3, said port being suitably coupled to a refrigerant supply'pipe 94. This refrigerant goes to the oppol site end of the chamber 14 through the passages 92 and thence through an expansion orifice 96 formedin the collar 9| and into the vexpansion chamber 15. The fluid then flows out through jthebore 85 into an expansion line 98 suitably coupled to the extension 84.

The admission of 'fluid from chamber 14 through the expansion orice 96 is controlledby a ball valve |00. The ball is mounted in a sleeve I| which is threaded upon a plug |02 and se cured th'ereonat desired adjustment by a lock nut |03. The sleeve |0| ispeened at its exposed endso that the ball |00 may project slightly from the end of the tube but cannot passvout of the tube. A spring I 04 between the plug |02Land-the ball normally presses the ball outwardly or toward .the adjacent end of the tube 12.k However,

the vball may be depressed to a limited extent for a purpose which will be explained hereinafter.`

The plug |02 is provided with a lug -which limits the extent to which the ball may be depressed.

The sleeve |0| is longitudinally grooved, as indicated at |05, so that liquid refrigerant may freely pass to the inner end thereof,vthat is the left hand end, .as viewed in Fig. 3. One of these slots is engaged by 'a set screw |05a, which prevents the sleeve from turning with respect to the fitting 88. However, as will now be explained,

means are provided for feeding the tube |0| toward and from the collar 9| `to adjust the expansion orifice 96.

The plug |02 has a stem |06 which is threaded into the bore of a tubular screw |01, and the. latter in turn is threaded into the bore of the tubular fitting 80. The outer threads of the tubular screw are of slightlyl different pitch from that of the inner threads, so 'that'when the screw is turned the plug and with it the sleeve |0|, will be moved with a micrometer adjustment.

To prevent leakage along the screw |01 it is surrounded near its outer end with packing material |08 suitably compressed by. a glandv |09. A cap |10 is screwed upon the outer end ofthe fitting 88 anda gas-tight seal for the cap is provided by a gasket The expansion chamber is sub-divided into When for any reason the apparatus is closed:

down and the refrigerant is allowed to grow warm the inner tube will expand sufficiently to close the orifice 96. .The relative expansion of the tube 12 with respect to the casing 'I0-1| will cause the collar 8| to pressagainst the ball |00, completely closing the orifice 96. If the parts are still farther expanded after complete closure takes place, spring |05 .will yield and prevent damage to any of the parts.

The cupsshaped washers ||2 in the expansion chambersl serve not only as heat radiating fins but are also useful to retain a certain amount of ,liquid refrigerant in this chamber, so that after the apparatus has been closed 'clownand the ori ce 9B has been completely closed suiiicient re' frigerant will be trapped in chamber 15 to permit of restarting the automatic control without priming.' A

While I have described a preferred embodi.- ment of my invention and certain modifications thereof it will be understood that thesel are to be taken as illustrative and not limitative of the invention and that I reserve the right to make various changes in form, construction and arrangements of parts without departing from the spirit and scope of my invention as pointed out in the following claims.

a plurality of chambers which are in communication with one another along the central axis of the tube 12. These sub-divisions are .formed by inserting into the tube a seriesof washers |l2.

each formed with a peripheral flange ||3 to space the washer from-the next adjacent washer and each ywasher is formed with a central aperture |04. The operation of this expansion valve is similar to that of Fig. 2 except that contraction and expansion of the outer casing is' controlled by temperature of the expanded refrigerant returning from the evaporator. In

'other words, thevlength of that.portion which 1 carries the ball |00 `is controlled by the heat being absorbed by the evaporator.. The greater Iclaim: 1. An expansion valve for controlling the expansion of compressed refrigerant in' a compres- 'sor-condenser-expander system, said valve com- -prising two 'rigid elongated members subject to chilled by expansion `of the refrigerant in said chamber and the port will be variably opened by contraction and closed by expansion of the this heatrload the Wider will the expansion orifice l open, and vice versa;y As in the valve shown in Fig. 2, the casing, which in this case comprises walls 10 and 1|, is substantially insulated from the inner tube 12 by the intervening layer of relatively warm liquid refrigerant lling chamber 14. For this reason it is not necessary to use'metals ofdifferent coefficients of expansion, I

because when the, system is operating the inner tube will alwayfsjbe materially cooler than the casing. This is accentuatedby the fins I2 within the tube12 which radiate heat to the expanding refrigerant faster than it ycan flow into the p tube from the relatively warm liquid refrigerantl in chamber 14. 'Ihe use5 of a.ball valve |00 on a' Arelatively large seat permitsvof a large opening With-a comparatively slight differential expansion of the parts. l j

inner member with respect to the outer member.

2. An expansion valve for controlling the expansion of compressed refrigerant in a compressor-condenser-expan'der system, said valve comprising two rigid elongated 'members subject to thermal expansion and contraction, one of the members enclosing the' other and shielding the same from, ambient temperatures, one. of the members forming anexpansion chamber and having a port constituting the sole inlet for admission of -said refrigerant to the chamber, and a closure for said port Icarried by the other member at the adjacent' end thereof, the two members being secured to each other at their other ends, said chamberbeing dened at least in part by the inner member whereby said inner mem^ bei' will be chilled by expansion of the refrigerant in said chamber andthe "port Will be variably opened and closed byl differential contraction ,l and expansion-of the two members, said mem-- bers being .so related that :when both are at a predetermined normaltemperature the port will y be completely clos'e`d.

` 3. Anexpansion valve for controlling the `ex-Y pansion of compressed refrigerant in a compres'-k sor-condenser-expander system,v said valve comprising two rigid elongated members disposed one within the other and the inner member having a, higher coefficient of expansion than the outer member, one of the members forming an expansion chamber and having a port constituting the sole inlet for admission of said refrigerant to the chamber, and avclosure for said port carried by the other member at the adjacent end thereof, the two members being secured to each other at their other ends, said chamber being dened at least in part by the inner member whereby said inner member will be chilled by expansion of the refrigerant in said chamber and the port will be variably opened and closed by differential contraction and expansion of the two members.

4. An expansion valve for controlling the eX- pansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprising two rigid elongated members disposed one within the other and the inner member having a higher coeiiicient of expansion than the outer member, one of the members forming an expansion chamber and having a port constitutingthe sole inlet for admission of said refrigerant to the chamber, and a closure for said port carried by the other member at the adjacent end thereof, the two members being secured to each other at their other ends, said chamber being defined at least in part by the inner member whereby said inner member will be chilled by expansion of the refrigerant in said chamber and the port will be variably opened and closed by differential contraction and expansion of the two members, said. members being so related that 'when both are at a predetermined normal temperature the port will be completely closed.

5. An expansion valve for controlling the expansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprising two rigid elongated members disposed one within the other and the inner member having a higher coeicient of expansion than the outer member, one of the members forming an expansion chamber and having a port for admission of said refrigerant to the chamber, and a closure for said port carried by the other member at the adjacent end thereof, the two members being secured to each other at their other ends, said chamber being defined at least in part by the inner member whereby said inner member will be chilled by expansion of `the refrigerant in said chamber and the port will be variably opened and closed by differential contraction and expansion of the two members, the

inner member being formed with heat radiating ns projecting into the expansion chamber.

6. An expansion valve for controlling the expansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprising two rigid thermo-expansive members disposed one within the other and providing an expansion chamber therebetween, a port at one end of the outer member constituting the sole inlet for admission of refrigerant to the chamber, and a closure for said port carried by the inner member at the adjacent end thereof, the two members being secured to each other at their other ends whereby the port will be variably opened and closed by differential'contraction and expansion of the two members.

7. An expansion valve for controlling the eX- pansion of compressed refrigerant in a comdisposed one Within the other and providing an expansion chamber therebetween, a port at one end of the outer member constituting the sole inlet for admission of refrigerant to the chamber, and a closure for said port carried by the inner member at the adjacent end thereof, the two members being secured to each other at 'their other ends whereby the port will be variably opened and closed by differential contraction and expansion of the two members, one of the members being formed with flanges to increase the heat transfer area thereof.

8. An expansion valve for controlling the ex- -pansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprising two rigid thermo-expansive members disposed one within the other and providing an expansion chamber therebetween, a port at one end of the outer member constituting the sole inlet for admission of refrigerant to the chamber, and'a closure for said port carried by the inner member at-the adjacent end thereof, the two members being secured to each other at their other ends whereby the port will be variably opened and closed by differential contraction and expansion of the two members, the outer member being formed eXteriorly With flanges to increase the heat absorbing area thereof.

9. An expansion valve for controlling the expansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprising two rigid members disposed one within the other and providing an expansion chamber therebetween, the inner member having a higher coefficient of expansion than that of the outer member, a pert at one end of the outer member constituting the'sole inlet for admission of refrigerant to said chamber, and a closure a higher coeiiicient of expansion than that" ofthe outer member, a port at one end of the outer member constituting the soleinlet for admission of refrigerant to said chamber, and a closure for said port carried by the inner member at the adjacent end thereof, the two members being 'secured to each other at their other ends whereby the port will be variably opened by differential 'l contraction and closed by differential expansion comprising two rigid thermo-expansive members of the two members, the members being so related that when both are at a predetermined normal temperature the port will be completely closed. 1

A 11. An expansion valve for controlling the expansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprising a tubular casing member providing an expansion chamber and having an inlet port at one end and an outlet port at the other end thereof,a valve controlling the inlet port, and a rigid stem member for the valve within the chamber and secured to the casing adjacent the outlet port, the stem member having a higher coefficient of expansion than that of the casing- -member, one of the members being formed with flanges to increase the heat transfer surface thereof.

12. An expansion valve -for controlling expan- I pansion of compressed refrigerant in a compres-v sor-condenser-expander system, said valve comprising a tubular casing providing an expansion chamber andhaving an inlet port at one end and an outlet port at the other, a valve controlling the inlet'port, a rigid stem for the valve within the chamber 'andvsecured to the casing adjacent the outletport, said stem having a t contraction and closed by expansion ofthe inner member with respect to the outer member.

- 1'7. An expansion valve for controlling the expansion of compressed refrigerant .in a compreshigher coe'cient of expansion than that vof the casing, and flanges exteriorly disposed on the casing to increase the heat transfer area thereof.

13. An expansion valve for controlling the expansion of compressed refrigerant in a compressorcondenser-expander system, said valve com- -prising two thermoexpansive tubular members disposed one within the other and secured together at one end, the inner member forming an expansion chamber and having a port at its vfree end for admission of said refrigerant to said chamber, and a closure carried by, the outer vmember for controlling admission of refrigerant through said port, the members being so related thatA the port will be variably opened by contraction and closed by expansion of the inner mem- A member for controlling admission of refrigerant through said port, the members being so related that the port'will be variably "opened by contraction and closed by expansion of the inner member lwith respect to the outer member but will be completely closed when both meinbers are at a predetermined normal temperature.

15. A n expansion valve for controlling the expansion of compressed refrigerantin a compressor-condenser-expander system, said valve comprising two thermoexpansive tubular members disposed one within the other and secured together at one end, the inner member forming an spect to the'outer member but will be completely closed when both members are at a predetermined normal temperature.

16. An expansion valve for controlling the expansion of compressed refrigerant in a com-pressor-condenser'expander system, said valve com.

prising twoI thermoexpansive tubular members disposed one within the other in annular spaced relation and secured together at one end, means for supplying compressed refrigerant to the space between the members, the inner member being formed with an expansion chamber and having a port at its free 'end for admission of refrigerant to said chamber, a closure carried by the outer member for controlling admission of refrigerant-into s aid port,the member being so related that the port will be variably opened by sor-condenser-expander system, said valve comprising two thermoexpansive tubular members disposed one within the other in annular spaced lrelation and secured together at one end,l meansfor admitting compressed refrigerant to the space between the members, the inner member forming an expansion chamber-and having a port at its free endfor, admission of the refrigerant from said space to said chamber, and a closurev carriedby the outer member and adapted tacontrol said port, the members being so related that the port will be variably opened by contraction and closed by expansion of the-inner member with respect to the outer member but will be completely closed when both members are at a predetermined'normal temperature.

18. An expansion valveA for controlling the expansion of compressed refrigerant in a compressor-condenser-expander system, said valve coniprising two thermoexpansive tubular membersy disposed one within the 'other in'annular spaced relation and secured together at one end, means for admitting compressed refrigerant to the space between the members,. the inner member form-- ing the expansion 'chamber' and having a port at its free end for admission of the refrigerant from said space to said chamber, and a closure carried by the outer member and .adapted to control said port, the members being so related that-'the port will be variably opened by contraction'and closed by expansion of the inner member with respect to the outer member, but will be completely closed when both members are at a` predetermined normal temperature, and fins on the inner surface of the inner member to increase the heat transfer area thereof.

19. 'An expansion valve for controlling the ext pansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprising two thermoexpansive tubular members disposed one within the other in annular spaced relation and secured together at one end,

means for'admitting compressed refrigerant to the space between the members,V the inner mem'- ber forming the expansion-chamber and having a port at its free end for admission of therefrigerant from said space to said chamber, a closure carried by the outer member and adapted to control said port, the members being so related that the port will be variably opened by contraction and closed by expansion of the inner -member with respect to the outer member but will be completely closed when both members are at. a predetermined normal temperature, the inner member being formed interiorly with annular flanges.'

20. An expansion valve for controlling' expansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprising three thermoexpansive tubular members disposed one within another to form an outer annular chamber, an intermediate annular chamber and an inner expansion chamber,

the outer and intermediate tubular members end for providing communication between the y intermediate and expansion chambers, an inlet port at the end of the intermediate chamber at which the inner tubular member is fixed to said casing for admitting compressed refrigerant from the condenser of said system to the intermediate chamber, an outlet port at the fixed end of the expansion chamber adapted to be connected to the expander of said system, provided at one end with an inlet port adapted to be connected to the low side of the expander of said system and provided at the other end with an outlet port adapted to be connected to the low side of the compressor of said system, and a closure for said port carried by the casing, the members being so related that the port will be variably opened by contraction and closed by expansion of the inner member with respect to the casing but will be completely closed when both members are at a predetermined normal temperature.

21. An expansion v alve for controlling expansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprising s three thermoexpansive tubular members disposed one within another to form an outer annular chamber, an intermediate annular chamber and an inner expansion chamber, the outer and intermediate tubular members being secured to each other at each end to form a double wall casing and to isolate the outer chamber from the intermediate chamber, the inner tubular member being xedto said casing at one end and having a port at the other end for providing communication between the intermediate and expansion chambers, an inlet port at the end of the intermediate chamber at which the inner tubular member is fixed to said casing for admitting compressed refrigerant from the condenser of said system to the intermediate chamber, an outlet port at the xed end of the expansion chamber adapted to be connected to the expander of said system, provided at one end with an inlet port adapted to be connected to the low side of the expander of said system and provided at the other end with an outlet port adapted to be connected to the low side of the compressor of said system, and a closure for said port carried by the casing, the members being so related that the port will be variably opened by contraction and closed by expansion of the inner member with respect to the casing but will be completely closed when both members are at a predetermined normal temperature, the inner member being formed interiorly with annular flanges.'

22. An expansion valve for controlling expansionV of compressed refrigerant in a compresso-condenser-expander system, said valve comprising three thermoexpansive tubular members disposed one within another to form an outer annular chamber, an intermediate annular chamber and an inner expansion chamber, the outer and intermediate tubular members being secured to each other at each end to form a double wall casing and to isolate the outer chamber from the intermediate chamber, the inner tubular member being fixed to' said casing at one end and having a port at the other end for providing communication between the intermediate and expansion chambers, an inlet port at the end of the intermediate chamber at which the inner tubular member is xed to said casing for admitting compressed refrigerant from the condenser of said system to the intermediate chamber, an outlet port at the xed end of the expansion chamber adapted to be connected to the expander of said system, said outer chamber being provided at one end with an inlet port adapted to be connected to the low side of the expander of said system and at the other end with an outlet port adapted to be connected to the low side of the compressor of said system, a closure forsaid port carried by the casing, the members being so related that the port will be variably opened by contraction and closed by expansion of the inner member with respect Ito the casing but will be completely closed when both members are at a predetermined normal temperature, the inner member being formed interiorly with heat radiating ns.,

23. An expansion valve for controlling expansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprisingy three thermoexpansive tubular members disposed one within another to form an outer annular chamber, an intermediate annular chamber and an inner expansion chamber, the outer and intermediate tubular members being secured to each other at each end to form a double wall casing and to isolate the outer chamber from the intermediate chamber, the inner tubular member being xed to said casing at one end and having a port at the other end for providing communication between the intermediate and expansion chambers, an inlet port at the end of the intermediate chamber at which the inner tubular member is xed to said casing for admitting compressed refrigerant from the condenser of said system to the intermediate chamber, an outlet port at the xed end of the expansion chamber adapted to b e connected' to the expander of said system, said outer chamber being provided at one end with an inlet port adapt-ed to be connected to the low side of the expander of said system and at the other end with an outlet port adapted to be connected to the low side of the compressor of said system, a closure for said port, and a mounting for the closure secured to the casing and including a spring backing for said closure, the members being so related that the port will be variably opened -by contraction and closed by expansion of the inner member with respect to the casing but will be completely closed when both members are at 'a predetermined normal temperature.

24. An expansion valve for controlling expansion of compressed refrigerant in a compressor-condenser-expander system, said valve comprising three thermoexpansive tubular members disposed one within'another to forman outer annular chamber, an intermediate annular chamber and an inner expansion chamber, the outer and intermediate tubular members being secured to each other at each end to form a double wall casing and to isolate the outer chamber from the intermediate chamber, the inner tubular member being fixed to said casing at one end and having a port at the other endV for providing communication between the intermediate and expansion chambers, an inlet port at the end of the intermediate chamber at which the inner tubular member is fixed to said casing for admitting compressed refrigerant from the condenser of said system to the intermediate chamber, an outlet port at the fixed end of the expansion chamber adapted to be connected t0 the expander of said system, said outer chamber being provided at one end with an inlet port adapted to be connected to the low side of the expander of said system and at the other end with an outlet port adapted to be connected to the low side of the compressor ofv said Vsystem,

a4 closure for said port, and a mounting for' the closure secured to the casing and including a spring backing for said closure, the members being so related that the-port will be variably opened by contraction and closed by expansion of the inner member with respect to the casing but will be completely closedwhen both members lare at a predetermined normal temperature,

the inner member being formed interiorly with annular anges.

THOMAS I. POTTER.

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