US1918272A - Thermostatic control valve for refrigerator cars - Google Patents

Description

July 18, 1933. ET A 1,918,272

THERMO'STATIC CONTROL VALVE FOR REFRIGERATOR CARS 3 Sheets-Sheet l Filed Nov. 6, 1930 InUnfJv-s July 18, 1933. J. KoPsA ET AL THERMOSTATIC CONTROL VALVE FOR REFRIGERATOR CARS Filed Nov. 6, 1930 3 Sheets-Sheet 2 Q wk kw Q orne qa Juiy 18, 1933. J. KOPSA ET AL.

THERMOSTATIC CONTROL VALVE FOR REFRIGERATOR CARS 3 Sheets-Sheet 3 Filed Nov. 6, 1930 orne g Emmi Patented July 18, 1933 UNETED STATES RATENT': @FFEQFS JULIUS KO?SA, C'F CHICAGO, AND EDMUND D. BRIGHAMT, JR., OF EIGHLAND PARK,

AMERICAN CAB CORCE'QBATION, OF CHICAGO,

'lE-EER-IIEOSTATIC GONTEQL VALVE FOR REFRIGERATOR CARS Application filed November 6, 1930. Serial No. 498,898.

This invention relates to an improved thermostatic control valve, and more particularly to a thermostatically operating mechanism which combines the functions of an expansion valve and adistribution valve and is especially designed for use in the mechanical refrigeration system of a railway refrigerator car. This improved valve is particularly adapted for use in a refrigerator car and refrigerating system therefor of the type disclosed and claimed in our copending application Serial No. 493,897 filed November 6, 1930. In a refrigerator car of this type, a compressor located beneath the car body is driven from the running gear of the car when the car is in motion. The compressed refrigerant is conducted to a condenser located in an exposed position on top of the car Where the refrigerant is condensed to liquid form and drains into a receiving tank Within the car. The liquid refrigerant is then permitted to expand in refrigerating coils located in hullr head compartments at the respective ends of the car, thus'absorbing heat from the air Within the car and the material stored therein, the expanded refrigerant being then conducted back to the compressor to complete the cycle. A portion of the ref erating coils are positioned in brine tanks uhich serve as storage reservoirs for cooling energy at the times when the car is stationary and hence the compressor is not being driven, so that the circulation system will be temporarily inoperative. The brine in these tanks is cooled down While the system is in operation so as to serve as a reserve body of heat-absorbing material, which will continue the refrigerating process during such times as the circulation system is not functioning. In this particular type of refrigerating system, certain of the refrigerating coils are positioned outside of the brine tank Within each bulk-head compartment, and are used for normally refrigerating the airivhich circulates through the bulkhead compartment from the storage chamber. .he refrigerant, after passing through these outside coils, passes through a coil positioned Within the brine tank and connected in series with the outside coils. In this Way, the cooling energy is first applied directly to the process of refrigerating the car, and any reserve cooling energy is stored in the brine Within the tank.

The improved thermostatic valve, Which forms the particular subject matter of this ,resent invention, is suitably positioned Within the storage chamber of the car and is sub ect to temperature changes in said chamher. The valve serves as an expansion valve Which restricts the flow of liquid refrigerant to the reirigerating coils, that is, it functions to separate the high pressure side of the system from the low pressure side, and in addition the valve functions to vary the path of flow of the refrigerant through the coils. When the temperature Within the car is above a predetermined maximum, the refrigerant is so directed as to flow first through the outside coils and then through the coils Within the brine tanks, but When the temperature has been lowered below this predetermined maximum, the refrigerant will be directed only through the coils within the brine tanks, the outside coils temporarily ceasing to function as a part of the refrigerating apparatus.

More specifically, the valve comprises a piston slidably fitted Within a closed housing, the housing and piston being provided With restricted passages for the liquid refrigerant, the liquid refrigerant entering the casing from a single supply pipe, and being alternatively discharged into one or the other of a pair of separate outlet pipes leading to the refrigerating coils in accordance with the position of the piston Within the casing. A suitable thermostat, subject to temperature changes in the storage compartment, serves to determine the position of the piston.

The principal'object of this invention is to provide an improved thermostatically opera-ting control valve for refrigerator cars, of the type briefly described hereinabove and disclosed more in detail in the specifications which follow.

Another object is to provide a simple, ellicient and automatically operating valve which serves simultaneously as an expan sion valve and a distribution valve.

Another object is to provide an improved form of temperature-controlled mechanism for regulating the flow of refrigerant in a refrigerating system.

Another object is to provide manually operable means for adjusting the valve so as to vary the temperature ran 'e maintained by the refrigerating system.

Another object is to provide improved means for sealing the valve against the escape of refrigerant.

Another object is to provide improved means for preventing vaporization of the refrigerant within the valve and consequent frosting of the valve body.

Other objects and advantages of this invention will be more apparent from the following detailed description of certain ap proved forms of apparatus embodying the principles of this invention.

In the accompanying drawings:

Fig. 1 is a diagrammatic view, partially in longitudinal vertical section, illustrating the principal elements of the refrigerator car and refrigerating system for use in which this improved valve is particularly adapted.

Fig. 2 is a horizontal section through one form of the valve.

Fig. 3 is an end view of the valve shown in Fig. 2.

Fig. 4 is a perspective view of the distributing piston.

Fig. 5 is a detail vertical section, taken substantially on the line 55 of Fig. 2.

Fig. 6 is a partial horizontal section through a valve embodying certain modifications.

Fig. 7 is a vertical section taken substan tially on the line 77 of Fig. 6.

Fig. 8 is a detached perspective view of a portion of the valve housing, as shown in Figs. 6 and 7.

Fig. 9 is a detail section showing a different form ofsealing means for the valve stem.

Fig. 10 is a perspective view of the packing unit shown in 9.

Referring first to Fig. 1, a type of railway car refrigeration system in which this improved valve may advantageously be used, will first be briefly described. The normally closed, insulated car body, indicated at 1, is interiorly provided adjacent each end thereof with vertical bulk-heads 26 which separate end bulk head compartments 2'? from the central chamber in which the goods to be refrigerated and shipped are stored. Lower and upper screened passages 29 and 30 in each bulk head 26 permit a circulation of air between the bulk-head compartments and the central storage compartment. One of the car trucks is indicated at 2, and 3 indicates a pair of the car wheels. It will be understood that a similar truck is located at the other end of the car.

The principal elements of the refrigerating system are the compressor A, the con denser B, a receiving tank C for holding liquid refrigerant, the improved temperature controlled expansion and distribution valve D, (forming the particular subject matter of the present invention), and two similar refrigerating units E and E, one located in each of the bulk-head compartments 27. All of these elements of the refrigerating system are connected in circuit, substantially in the order named.

The compressor A, of any suitable type, is supported in a housing a and is preferably driven from one of the car axles or wheels in any suitable manner, as diagrammatically indicated by the sprocket gearing 5. The compressed vaporized refrigerant from compressor A flows through pipe 6 to the condenser B, which is carried in an exposed position outside of the car body, preferably on top of the car. The compressed refrigerant is condensed or liquefied in condenser E and flows down through pipe 7 into the receiving tam. C. From the supply in tanlt C the liquid refrigerant is forced through pipe 8 to the improved expansion and distribution valve 1), which is preferably located centrally in the storage compartment of the car so as to he respoi nve to the temperatures prevailing in this storage chamber. Preferably, a suitable reducing valve 9 is positioned in the pi pe line 8 so that the liquid refrigerant will be delivered to the control valve D at a. constant pressure, regardless of pre .ure variations that may occur in that portion of the system between compressor A and the reducing valve 9, as described above.

The improved control valve D, which will be described more in detail hereinafter, performs two distinct functions, one of which is to permit the flow of the liquid refrigerant to the refrigerating elements in limited or restricted quantities only, so that the refrigerant can expand and vaporize in the low pressure side of the system which extends from the valve D to and through the refrigerating elements E and E and back to the compressor A. The other function of valve D is to change the distribution or flow of the refrigerant in accordance with temperature changes in the space in which this valve is located. There are two outlets leading from valve D, designated as 10 and 11. hen any tenmeratures above a predetermined maXimum prevail in the car, or in the space adjacent the valve D, the refrigerant will be discharged through pipe 10. Vhen the temperature in the car has been lowered below this predetermined maximum, the How of refrigerant will be changed to the outlet pipe 11, the flow through pipe 10 being cut off. The supply pipe 10 has two branches 10 and 10 which extend to the two similar flows through inner coil 13 as in the elerefrigerating elements E and E, respectively. In a similar manner, the supply pipe 11 is provided with two branches 11 and 11.

The two refrigerating elements E and E will be substantial duplicates although two different types of piping connections have been shown in Fig. 1 at the two ends of the car. One of these refrigerating elements will be positioned in each of the bulkhead compartments 2?, which are similar to the compartments formerly used for holding the ice supply. The refrigerating element E comprises a central brine tank 12, preferably a closed sheet metal tank containing a supply of brine or other equivalent material having a low freezing point, there being a pipe coil 13 positioned within the brine tank 12. The object of this brine tank is to act as a storage reservoir for cooling energy, or in other words, it provides a body of heat absorbing material, which will function as a refrigerating element in the same manner as a supply of ice would do, when the mechanical refrigerating system is temporarily out of action. Positioned outside of the brine tank 12, and preferably one at each side thereof. are two similar refrigerating pipe coils 15 and 16, these coils being connected together at their lower ends in open communication with the supply pipe 10, as indicated at 17. The upper ends of the two outside coils 15 and 16 are joined together at 18. from which connection leads a pipe 19 to the lower end of the pipe coil 13 within the brine tank 12. A discharge pipe 20 leads from the upper end of inside coil 13 back to the compressor A beneath the car. It will be noted that the two outside coils 15 and 16 are connected in parallel, and both are in series with the inside pipe coil 13, so that the refrigerant when supplied through pipe 10 will first flow through the two outside coils. then through the inside coil, and the expanded and heated refrigerant from all of the coils will flow back through pipe 20 to the compressor A.

Another form of piping connection is shown for the refrigerating element E at the opposite end of the car. Such parts of this element as are similar to the corresponding parts of element E are indicated by similar but primed reference characters. Refrigerating element E differs from element E in that the outer coils are connected in series instead of in parallel, and an additional coil 80 is positioned above the tank 12. The supply pipe 10 leads to the lower end of coil 15 from the upper end of which a pipe 81 leads to the lower end of the opposite. outside coils 16. The upper end of coil 16 connects with one end of upper outside coil 80 which discharges at its other end into the fitting 18 from which the refrigerant ment E, just described.

The other supply lines 11 and 11 lead from valve D to the respective connections 18 and 18, thus feeding the refrigerant directly into the inner coils 13 and 13 through pipes 19 and 19. At such times as the supply flows hrouga pipes 11 and 11, the supply pipes 10 and 10 will be cut off so that all of the outer refrigerating coils of both elements E and E will no longer be supplied with compressed refrigerant.

"It is to be understood that while in Fig. 1 we have disclosed two different types of refrigerating elements E and E, ordinarily both of the elements, as used in any one car, will be of the same type.

The improved valve mech anism D will now be described, referring first to the form shown in Figs. 2, 3, 4t and 5 of the drawings. The main valve block 22 is provided with heads or closures 23 and 2%, these three parts being bolted or otherwise secured together to form a closed fluid-tight casing. The valve block 22 is formed with a central cylindrical piston chamber 25, in which the piston 29 has a snug slidable fit. The pipe 8 which conducts the liquid refrigerant to the valve connects with an inlet port 30 from which lead a pair of similar restricted branch inlet passages 31 opening at spaced points into the pistonchamber 25. A pair of similarly spaced restricted outlet passages 32 open out of chamber 25 in substantial alignment with the first restricted passages 31, and at the opposite side of the valve casing, and lead to outlet ports 33 and 34 in which the supply pipes 10 and 11 are respectively connected. The cylindrical surface of piston 29 is formed with a pair of similar annular grooves 35 substantially of the same diameter as passages 31 and 32. These passages 35 are somewhat closer together than the pairs of passages 31 and 32 so that when one groove 35 is in alignment with one pair of restricted passages 31 and 32, a solid portion of piston 29 will be interposed between the other aligned passages 31 and 32, all as indicated in Fig. 2. Other forms of restricted passages 35, such as diametrical passages extending directly through the piston 29, could be used, instead of the annular grooves 35, but these annular grooves have the advantage of not requiring aprurate alignment of the passages 31 and 32 at the opposite sides of the valve casing. No matter what the angular relation of these passages 31 and 32 may be, they will be connected by one of the grooves 35 as long as they are centered in the same diametrical plane. A valve stem 36 projects out through a suitable passage in the extension 37 of the valve casing, a suitable packing 38 being held about stem 36 by means of gland 39 and cap member 40 screwed on to the outer threaded end portion 41 of extension 37.

This packing serves to prevent the escape of fluids from the valve casing about the slidable valve stem 36. A stop screw 42 threaded into the opposite head member 23 of the valve casing and provided with a lock nut 43 serves to limit the movement of piston 29 in one direction.

A thermostat-supporting frame 44 has a central hub portion 45 which is slid-ably keyed at 46 on the extension 37 of the valve casing. The frame 44 is preferably in the form of a rather heavy metal casting, since it is essential that this frame be rigid and maintain its fixed form under all conditions. A compression spring 47 surrounds the extension 37 and is confined between one side of hub 45 of supporting frame 44, and a nut or collar 48 screwed on the threaded extension 41 of the casing. This spring 47 serves to urge the supporting frame inwardly into engagement with an annular cam ring 49 which is interposed between the head 24 of the valve casing and the inner end of hub 45 of the supporting frame 44. The engaging end surfaces of hub 45 and cam ring 49 are provided with pairs of mating cam surfaces 50. A manually operable regulating lever 51 extends outwardly and downwardly from the cam ring 49, and it will be apparent that as this lever 51 is oscillated in one direction or the other, the supporting frame 44 will be urged outwardly against the resistance of spring 47, or will be moved inwardly by this spring. The lever 51 moves over a calibrated dial 52, which may be formed integrally with the end head 24 of the valve casing.

A pair of similar flat bi-metallic thermo static bars 53 are anchored at their outer ends 54 in the supporting frame 44 and have inner forked end portions 55 engaging the outer threaded end portion 56 of valve stem 36. Adjusting nuts 57 and lock nuts 57 at either side of the bars 53 secure these thermostatic bars to the valve stem so that as these bars bow outwardly or inwardly in response to temperature changes, the valve stem 36 will be moved to slide the piston 29 in the piston chamber 25. As the bars 53 are heated, they will bow inwardly, that is, so as to move the valve stem 36 into the casing, and when cooled the bars will bend in the opposite direction so as to withdraw the stem 36 from the casing. It will be apparent that one of these thermostatic bars of a fixed size and length and composed of certain metals will bow or bend a certain amount in response to certain predetermined temperature changes. In order to acquire the necessary power to positively operate the valve members a plurality of these thermostatic bars are coupled to get-her so as to multiply the power applied to the valve stem. As here shown, a pair of auxiliary bars 58 of similar length are superposed over each primary thermostatic bar 53, and are mounted at their outer ends 59 in the supporting frame 44 in outwardly staggered relation. Bosses 60 adjacent the inner ends of bars 58 engage the next adjacent thermostatic bar, and a coupling yoke '61 provided with locking screws 62 is secured about the group of thermostatic bars. It will now be seen that the two groups of thermostatic bars are so positioned and connected together that they will move in unison in response to temperature changes, and the aggregate power appliedto valve stem 36 will be adequate to insure proper movement of the piston 29.

When a certain temperature is reached in the locality of this valve D, the thermostatic bars will bow inwardly so as to move one of the channels 35 into alignment with the inner pair of inlet and outlet passages 31 and 32, so that the refrigerant will be directed into the supply pipe 10, all as shown in Fig. 2. lVhen the temperature at this locality has fallen a certain predetermined amount, that is, when the desired low temperature has substantially been established in the car, the thermostatic bars will bow outwardly so as tobring the other channel 35 into alignment with the outer pair of restricted passages 31 and 32 and complete a. supply connection leading to pipe 11. At the same time the connection leading to pipe 10 will be cut off, since a solid portion of cylindrical piston 29 will then be interposed between the inner pair of passages 31 and 32.

By moving the hand lever 51 over the calibrated dial 52, the critical temperatures at which these changes in refrigerant flow take place can be varied as desired, that is, the temperature range maintained in the car can be predetermined. It will be noted that the rigid supporting frame 44, the thermostatic bars and 58, and the valve stem 36 and piston 29 will be adjusted inwardly and outwardly as a unit as the cam ring 49 is turned to different positions between the valve casing and the hub 45 of supporting frame 44. This serves to vary the position of piston 29 for any given temperature, and will obvious ly determine the critical temperatures at which the alternative fiow-passages through the valve are brought into alignment.

The restricted passages 31, 35 and 32 are made sufficiently small to restrict the flow of the high pressure liquid refrigerant supplied through pipe 8, so that the refrigerant will not expand and vaporize and thus absorb heat until it flows into the low pressure side of the system extending from the valve D through the refrigerating elements E and E back to the compressor A. In this manner the automatic valve D combines the functions of an expansion valve and adistribution valve.

Referring now to the general operation of the refrigerating system which embodies the improved valve D, it will be apparent that whenever the car is in motion along the trackway the compressor A will be driven and the refrigerant will be caused to circulate, the vaporized refrigerant being compressed in compressor A and transferred under high pressure through the condenser B, where it is relieved of a portion of its heat and con densed, and then flows in liquid form, still under high pressure, into the receiving tank G. This liquid refrigerant is forced to and through the valve D, which delivers it in re stricted quantities to the two refrigerating elements E and E, wherein the refrigerant expands and vaporizes and thus absorbs heat from the air circulating through the bulkhead compartments 27 from and back into the central storage chamber 28. As long as the temperature in the storage compartment 28 is above the predetermined temperature which valve 1) has been set to maintain in this portion of the car, the refrigerant will flow first through the outer coils l5 and 16 (and coil 80 if used) which directly absorb heat from the circulating air passing through the bulk-head compartment. The expanding refrigerant then passes from the outer coils through the inner coil 13 and any cooling energy remaining in the refrigerant is utilized to lower the temperature of the brine within tank 12, the expanded and somewhat heated refrigerant then being returned through pipe 20 to the compressor A, thus completing the cycle. lVhen the temperature has been lowered to the desired point in storage chamber 28, the valve D acts automatically to cut off the supply of refrigerant to the outer coils 15, 16 and 80, but the refrigerant then flows through pipes 11 and 19 directly through the inner coil 13 so as to continue to store cooling energy in the brine confined within tank 12. If, and when, the temperature in the central storage compartment of the car rises above the predetermined maximum, the valve 1) will again operate to direct the flow of re frigerant first through the outer coils and then through inner coil 13. In this manner a substantially constant temperature can be maintained within the storage compartment of the car and this temperature can be pre determined by a proper manual setting of the thermostatically operated valve D.

Referring now to Figs. 6, 7 and 8, we will note certain modifications or improvements which might be used instead of the equivalent forms shown in Figs. 2 and 3. Parts indicated by the same reference characters will be understood to be substantially the same as those already described. In this modification the main valve block is composed of two parts consisting of an outer shell or casing 63 and an interfitting cylindrical member 64. The cylindrical piston chamber 25 is formed within the inner member 64 and the outer portion of this member 64 is largely cut away so as to form a liquid-holding jacket or space 65 surrounding the inner piston chamber. This jacket 65 is enclosed by a pair of annular end collars 66, and is divided by a pair of intermediate collars 67 which are, however, provided with passages 68 which place all portions of the jacket 65 in communication with one another. The inner collars 67 are completely cut away at 69, substantially opposite the inlet port 30 which opens into the jacket 65, as at 70. The restricted passages 31 lead from jacket 65 into the central cylindrical chamber 25, as in the first described form of the invention. The restricted outlet passages 32 lead out through the respective collar portions 67 so as to be entirely out of communication with the surrounding liquid jacket 65.

The operation of this form of valve will be the same-as described hereinabove in connection with Fig. 2, but it will be apparent that a jacket of liquid-refrigerant will be maintained around the valve members. This tends to maintain substantially equal temperature conditions throughout the valve casing, so that the parts will not expand or contract unequally and thus freeze together or lose the proper working fit to maintain the valve connections. This jacket will also minimize the expansion of refrigerant therein and prevent consequent frosting of the exterior portions of thevalve.

In this modified form of valve structure, an end head 71 is formed on the inner end of easing extension 37, and is clamped against a similar end head 72 formed on one end of the outer shell 63 of the valve casing. The two halves of a diaphragm chamber 7 3 are formed in the leading faces of the heads 31 and 32, and a flexible corrugated metallic diaphragm 74 is clamped at its outer edges between the two heads 71 and 72, the central portion of this diaphragm being sealed to the valve stem 36, as by means of the nuts 75. This diaphragm 74 permits free movement of the valve stem 36 inwardly or outwardly, but at, the same time seals the end of the valve casing so that no fluids can escape therefrom. It will be understood that this diaphragm takes the place of the packing 38 disclosed in the first described form-of the valve. It is to be understood that the liquid jacket feature 65 could be used without the 1 diaphragm 75, or that the sealing diaphragm 75 could be substituted for the packing means 38 shown in Fig. 2 without using the liquid jacket in the valve chamber.

Another form of sealing means for the valve stem is shown in Figs. 9 and 10. The improvedsealing assembly shown at 82 in Fig. 10 comprises a hollow cylindrical metallic shell provided with closed end plates 84 having central openings 85. A soft rubber annulus 86 fills the shell or housing 82 except for the central cylindrical passage 87 which aligns with the end openings 85 in the shell. A. central metallic stem 88 (which forms a sectionof the valve stem when the packing unit is installed) is of smaller diameter than passage 87 and projects therethrough and through the end openings 85 of the casing. A central collar or disk 89, formed on stem 88, is embedded in the soft rubber packing 86. This soft rubber annulus is vulcanized to the disk 89 and the interior of shell 82 or secured thereto in any other suitable manner so as to form a hermetically sealed joint and prohibit the passage of any fluids through the shell 82.

The end of valve stem 36 is connected with one end of stem 88, for example by being threaded therein as shown at 90, and the other end of stem 88 is similarly connected with a valve stem extension 91 which is guided at 92 in the housing 93 which encloses the packing unit 82 and is secured to the end of the valve casing as indicated at 94. Suitable gaskets 95 and 96 are clamped between the ends of shell 82 and the adjacent end walls of valve casing 63 and housing 93 respectively so as to prevent the flow of fluids around the shell 82.

The valve stem has only a small range of movement (only a small fraction of an inch) and the soft rubber mass will yield sufficiently to permit these movements without destroying the seal between the rubber mass and the metallic parts. This improved type of packing can be used effectively in any installation where the refrigerants used are such as not to attack or injuriously affect the soft rubber or equivalent packing material.

Any combination of these various modifications, or their equivalents, are contemplated as being within the scope of this invention. It will also be apparent that other forms of thermostats could be used instead of the coupled thermostatic bars herein disclosed. Any suitable form of temperature responsive member capable of imparting the necessary movements to the valve stem 36 and piston 29 might be included in this con struction.

Any suitable means for supporting this valve assembly may be used. lVhen employed in a refrigerator car it will preferably be suspended in a horizontally extending position beneath the roof of the car and closely adjacent thereto so as not to interfere with movements within the car, all as roughly indicated in diagram in Fig. 1.

We claim:

1. A combinedexpansion and distributing valve for refrigerating systems comprising a valve body formed with a central piston chamber, an inlet passage for liquid refrig- 1 erant formed in the body and terminating in two spaced apart restricted branch passages leadmg into the piston chamber, a pair of similarly spaced restricted passages leading from the chamber to a pair of outlet passages, a piston slidably fitted in the chamber and provided with a pair of separate restricted passages, each adapted toalign with one of the inlet branch passages and with one of the restricted passages, the passages in the piston being so spaced that when one is in position to complete a continuous restricted passage through the valve body, communication between the other branch inlet passage and the aligned outlet passage will be closed by an unbroken portion of the piston, a valve stem extending from the piston outside the valve body, a thermostat connected with the valve stem for moving the valve, a frame for supporting the thermostat, and means for manually adjusting the frame toward or from the valve body to adjust the position of the piston at any one temperature and thus vary the effective operating temperature range of the valve, said means comprising a spring for urging the frame in one direction, and a manually operable cam for urging the frame in the other direction in opposition to the spring.

2. A combined expansion and distributing valve for refrigerating systems comprising a valve body formed with a piston chamber and also formed with an annular jacket chamber surrounding the piston chamber, an inlet passage for liquid refrigerant leading into the jacket chamber, a pair of spaced apart restricted passages leading from the jacket chamber into the piston chamber, a pair of similarly spaced restricted outlet passages leading from the piston chamber to outlet ports in the valve body, a piston slidably fitted in the piston chamber and provided with a pair of separate restricted passages each adapted to align with one of the restricted inlet passages and one of the restricted outlet passages, the passages in the piston being so spaced that when one of them is in position to complete a continuous restricted passage through the valve body the other aligned inlet and outlet passages will be closed by an interposed solid portion of the piston, a valve stem extending from the piston and guided through an extension of the valve body, and a thermostat connected with the outer portion of the stem for moving the piston in accordance with temperature changes in the space adjacent the valve.

3. A combined expansion and distributing valve for refrigerating systems comprising a valve body formed with a piston chamber and also formed with an annular jacket chamber surrounding the piston chamber, an inlet passage for liquid refrigerant leading into the jacket chamber, a pair of spaced apart, restricted passages leading from the jacket chamber into t e piston chamber, a pair of similarly spaced restricted outlet passages leading from the piston chamber to outlet ports in the valve body, a piston slidably fitted in the piston chamber and provided with a pair of separate restricted pasages each adapted to align with one of the restricted inlet passages and one of the restricted outlet passages, the passages in the piston being so spaced that when one of them is in position to complete a continuous re- 'cted passage through the valve body the other aligned inlet and outlet passages will be closed by an interposed solid portion of the piston, a valve stem extending from the piston and guided through an emension of the valve body, a thermostat connected with the outer portion of the stem for moving the iiston in accordance with temperature changes in the space adjacent the valve, and means for adjusting the assembled thermostat, stem and piston along the axis of the valve stem for changing the operative temperature range of the valv l. A combined expansion and distributing 'alve for refrigerating systems comprising a valve body formed with central piston chamber, an inlet passage for liquid refrigerant formed in the body and terminating in two spaced apart restricted branch passages leading into the piston chamber, a pair of similarly spaced restricted passages leading from the piston chamber to a pair of outlet passages, a piston slidably fitted in the chai her and provided with a pair of separate restricted passages, each adapted to align with one of the branch inlet passages and one of the restricted outlet passages, the passages in the piston being so spaced that when one of them is in position to complete a continuous restricted passage through the valve body, communication between the other branch inlet passage and aligned outlet passage will be closed by an interposed solid portion of the piston, a valve stem extending from the piston and guided through an extension of the valve body, a thermostat connected with the outer portion of the valve stem for moving the piston, a frame for sup porting the thermostat and slid ably mounted on the body extension, a spring for urging the assembled frame, thermostat, stem and piston in one direction along the axis of the valve stem, and manually operable cam means for moving the assembly in opposition to the spring.

5. A combined expansion and distributing valve for refrigerating systems comprising a valve body formed with a central piston chamber, an inlet passage for liquid refrig= erant formed in the body and terminating in two spaced apart restricted branch passages leading into the piston chamber, a pair of similarly spaced restricted passages leading from the piston chamber to a pair of outlet passages, a piston slidably fitted in the chamber and provided with a pair of separate restricted passages, each adapted to align with one of the branch inlet passages and one of the restricted outlet passages, the passages in the piston being so spaced that when one of them is in position to complete a continuous restricted passage through the valve body, communication between the other ranch inlet passage and aligned outlet passage will be closed by an interposed solid portion of the piston, a valve stem extending from the piston and guided through an extension of the valve body, a thermostat connected with the outer portion of the valve stem for moving the piston, a frame for supporting the thermostat and slidably mounted on the body extension, a spring for urging the assembled frame, thermostat, stem and piston in one direction along the axis of the.

valve stem, a rotary cam interposed between portions of the frame and valve body and adapted to move the mentioned assembly in opposition to the spring, a lever for moving the cam, and a calibrated dial over which the lever is movable.

6. A combined expansion and distributing valve for refrigerating systems comprising a valve body formed with a central piston chamber, an inlet passage for liquid refrigerant formed in the body and terminating in two spaced apart restricted branch passages leading into the piston chamber, a pair of similarly spaced restricted passages leading from the piston chamber to a pair of outlet passages, a piston slidably fitted in the chamber and provided with a pair of separate restricted passages, each adapted to align with one of the branch inlet passages and one of the restricted outlet passages, the passages in the piston being so spaced that when one of them is in position to complete a continuous restricted passage through the valve body, communication between the other branch inlet passage and aligned outlet passage will be closed by an interposed solid portion of thepiston, a valve stem extending from the piston and guided through an eirtension of the valve body, a sealing means in the extension around the valve stem, a thermostat connected with the outer portion of the valve stem for moving the piston, a frame for supporting the thermostat and slidably mounted on the body extension, a spring for urging the assembled frame, thermostat, stem and piston i in one direction along the axis of the valve stem, and manually operable cam means for moving the assembly in opposition to the spring.

7. A combined expansion and distributing valve for refrigerating systems comprising a valve body formed with a central piston chamber, an inlet passage for liquid refrigerant formed in the body and terminating in two spaced apart restricted branch passages leading into the piston chamber, a pair of similarly spaced restricted passages leading from the piston chamber to a pair of outlet passages, a piston slidably fitted in the cham ber and provided with a pair of separate restricted passages, each adapted to align with one of the branch inlet passages and one of the restricted outlet passages, the passages in the piston being so spaced that when one of them is in position to complete a continuous restricted passage through the valve body, communication between the other branch inlet passage and aligned outlet passage Will be closed by an interposed solid portion of the piston, a valve stem extending from the piston and guided through an extension of the valve body, a chamber in the valve body through which the stem projects, a sealing means in this chamber sealed at its outer edges to the body and centrally to an intermediate portion of the stem, a thermostat connected with the outer portion of the valve stem for spring.

JULIUS KOPSA. EDMUND D. BRIGHAM, JR.

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