US1847546A - Refrigerating apparatus - Google Patents

Description

March 1, 1932.

H. W. VV ISHART ETAL REFRIGERATING APPARATUS 4 Sheet-Sheet 2 Filed March 8, 1930 March 1, 1932. w, w s ET AL 1,847,546

REFRIGERATING APPARATUS Filed March 8, 1930 4 Sheets-Sheet 3 INVENTORS ATTORNEYS March 1932- H. w. WISHART ET AL 1,847,546

REFRI GERAT ING APPARATUS Filed March 8, 1930 4 Sheets-Sheet 4 f INYfiEZNTORS ATTORNEY6 Patented Mar. 1, 1932 UITED STAT S PATENT OFFICE LD W. WISHART AND ROBERT L. ALEXANDER, OF CLINTON, IOWA, ASSIGNORS TO THE OLIMAX ENGINEERING COMPANY, OF CLINTON, IOWA, A CORPORATION OF DELAWARE nnrnIennA'rme ArrAnArus Application filed March 8, 1930. Serial No. 434,252.

This invention relates to refrigeration, and more particularly concerns evaporators for use in connection with refrigeration systems of the domestic type. 1

Mechanical refrigeration systems general ly comprise suitable means for compressing a refrigerant fluid and for liquefying such fluid by lowering its temperature after it has been compressed. After being liquefied, the refrigerant is permitted to expand through a suitable valve, tube or other pressure reducing device into an evaporator wherein the gasification of the liquid refrigerant takes place and the desired heat absorbing or refrigerating effect is produced. The evaporator customarily includes a chamber of considerable capacity, and the liquefied refrigerant from the condenser is expanded directly into such chamber and permitted to evaporate therein and in the tubes communicating therewith. This construction is bulky and requires the use of a large amount of refrigerant in the system.

When the refrigerant is compressed by mechanical means, such as a pump, a lubricating oil is usually employed to seal and lubricate the pump parts, and some of this oil is usually carried over by the gaseous refrigerant from the compressor, mingles or forms a solution with the liquid refrigerant in the condenser and flows into the evaporator. The gasification of the refrigerant in the large evaporator chamber separates the refrigerant from the oil, and the oil accordingly accumulates in the evaporator and decreases the heat absorbing efiiciency thereof. Further, the accumulation of oil in the evaporator chamber soon depletes the oil supply in the compression mechanism with the result that the moving parts are not properly sealed orlubricated.

In a domestic refrigeration system it is usually desirable that means he provided in connection with the evaporator for freezing water, desserts or .other liquids. Although 'the desired refrigerator temperatures usuallv range from about 40 to F., the evapor ator ,must be capable of cooling liquids to temperatures well below the freezing point,

50 and it is further desirable that these low temperatures be rapidly obtainable so that ice or frozen desserts may be produced in a minimum time.

lVith the above and other considerations in mind, it is proposed in accordance with the present invention, to provide an improved evaporator for refrigeration systems embodying alight and compact construction and of just sufficient refrigerant capacity to produce the desired heat absorbing effect. Our improved evaporator is designed to effect the continuous return to the compression mechanism of any oil or other lubricant which may be carried into the evaporator with the refrigerant. It is further proposed to pro vide an evaporator incorporating means for rapidly freezing liquids in suitable containers while maintaining the refrigerator box at the desired temperature above the freezing point.

In one embodiment of the invention, unitary refrigerant receiving and expansion means are included in the evaporator structure, and in this modification, means may be provided'for passing the cool evaporated refrigerant from the evaporator in heat exchanging relation with the comparatively warm liquid and gaseous refrigerant in the characteristic features of the invention will become apparent as the description thereof progresses.

In general, the objects of the inventmn are carried out by providing an evaporator including a long continuous coil of pipe or tubing in which the gasification of the refrigerant takes place and through which any lubricant which may accompanymg the refrigerant is drawn in the form of a foam b the expanding refrigerant. The coiled tubsecond small header near the upper end of the evaporator. According to one form of the invention, the gasified refrigerant from the upper header is passed through suitable means in heat exchanging relation with a refrigerant receiver which forms a part of the evaporator structure and which is located with the evaporator within the refrigerator cabinet or other space to be cooled.

In a modified form of the invention, a portion of the tubing which forms the expansion coil is disposed within the freezing compartment of the evaporator and forms means for supporting the removable trays or other containers which carry the liquids to be frozen in this compartment. With this arrangement, the liquid trays may be arranged to come into direct contact with the expansion coil, and if desired, the coldest portion of this coil may be employed for this purpose. In this manner, the trays, together with the liquids contained therein, are quickly lowered to a freezing temperature.

The invention will be best understood by considering the embodiments thereof illustrated in the accompanying drawings, in which Figure 1 is a side elevation of an evaporator embodying the present invention;

Fig. 2 is a front end elevation of the evaporator shown in Fig. 1;

Fig. 3 is a sectional view showing the cover plate mounting means; I

Fig. 4 is an elevation similar to Fig. 1, showing a modified form of evaporator embodying the present invention;

Fig. 5 is a rear end view of the evaporator shown in Fig. 4;

Fig. 6 is a sectional view taken along the line 6-6 of Fig. 4, and viewed in the direction of the arrows;

Fig. 7 is an elevation similar to Figs. 1 an 4 showing an evaporator embodying a further modification of the invention;

Fig. 8 is a sectional view taken along line 88 of Fig. 7 and viewed in the direction of the arrows;

Fig. 9 is a sectional view taken along the line 99 of Fig. 7, and viewed in the direction of the arrows;

Fig. 10 is a partial side elevation of an evaporator and receiving means showing a modified form of heat exchanging means; and

Fig. 11 is an elevation similar to Fig. 10, but partly in section, showing an evaporator embodying a modified form of'refrigerant receiving and expansion means.

Referring to the drawings, and more parlocated. The turns of the coil 10 are held in proper spaced relation by means of side straps 12, which may be tinned, soldered, or welded to the outer surfaces of the coil turns. The straps 12 are preferably tied together by vertically spaced transverse bolts 13, and if desired, the pressure exerted by these bolts through the straps 12 may be relied upon to hold the straps against the sides of the coil 10.

Two vertically spaced, horizontally disposed headers 20 and 22 are preferably disposed within the coil 10, being located at the bottom and the top. of the space therein respectively. The headers may take any suitable form, but, as shown, comprise cylindrical chambers formed of sheet metal or any other suitable material. The outlet end 21 of the coil 10 is connected to the lower header 20 adjacent the front end thereof, and the headers 20 and 22 are interconnected by one or more tubes 23 and 24. The tubes 23 and 24 may be arranged in any suitable manner, and in the disclosed embodiment, these tubes extend in opposite directions from points near the top of the header 20 to points near the bottom of the upper header 22. The tubes 23 and 24 are preferably located respectively adjacent the front and rear ends of the headers as shown in Fig. 1. An outlet pipe 25 is connected to the top of upper header 22 adjacent the rear end thereof.

A liner 28 of sheet metal or other suitable material is preferably disposed in the space within the coil 10 and between the headers 20 and 22. This liner may be fastened to the coil 10 and the bolts 13 in any suitable manner, and forms a freezing compartment 26. Suitable lugs 29 are preferably provided on the sides of the liner 28 for slidably supporting a freezing tray 27 adjacent the upper end of the compartment 26, and supporting ridges 30 may be formed in the bottom of the liner 28 for supporting a second freezing tray at the lower end of the compartment. With this arrangement, when it is desired to subject large quantities of liquid or other foods to freezing temperature, a deep tray, indicated in broken lines at 19, may be substituted for the two smaller trays 27, the tray being supported by the lugs 29 which engage the outwardly extending rim or flange at the top of the trays employed. The large tray 19 may rest onthe ridges 30 at the base of the freezing compartment 26 if desired. Since no transverse tray supporting shelf or other obstruction extends across the freezing compartment 26, large packages nemm ; or objects may be placed-within the freezing 9 is preferably provided .at the rear end ofthe compartment 26 to form a stop for the freezing trays, and to at least partially close the rear end of this compartment.

In order to enhance the appearance of the device, a cover plate 31, having a central ening 34 therein, is preferably provided on t e front of the evaporator, which is the only portion of the device readily visible as it is viewed in its position in the refrigerator cabinet. This plate may be enamelled, or may be given any other suitable finish, and is preferably attached by means of the brackets 32 bolted to the extensions 33 on the forward ends of the horizontal straps 12. The evaporator is suitably mounted within a refrigerator cabinet, and as disclosed herein, a plurality of supporting straps 14 having out-- wardly bent upper ends 15 are riveted or otherwise suitably secured to'the side straps 12 and are employed to sus end the eva orator from the top of the refrigerator ca incl 18. As shown herein, a supporting plate 17 is fixed to the inside of the top of the cabinet, and the ends 15 of the straps 14 are secured to this plate by the rivets 16 or other suitable means.

The inlet pipe 11 of the evaporatorcommunicates with the condenser of the refrigerating unit employed through suitable expansion means, and the outlet pipe is connected to the intake of the compressor of this unit. These connections are made in the usual manner through the wall of the refrigerator cabinet. Snce compression, condensing, and expansion means for refrigeration units of this type are well known in the art, and since these means form no part of the present invention, a showing thereof has been omitted to simplify the drawings.

The liquid refrigerant from the condenser expands into the inlet tube 11 and passes directly into the coil 10 of the evaporator, and a m xture of gaseous and liquid refrigerant passes through this tube. Evaporation of the refrigerant takes place throughout the length 4 of the coil 10, and the entire surface of this coil acts as an effective heat absorbing body. After passing through the entire length of the coil 10, the evaporatedgas, together w th any liquid refrigerant which may remain unevaporated, passes into the small lower header 20. In the lower header, the remaining liquid refrigerant evaporates, and the gaseous refrigerant passes through the tubes 23 and 24 to the upper header 22, and thence through the outlet pipe 25 to the suction line of the compressor. The upper header 22 acts as a dry gas container, and as an evaporator for any wet refrigerant vapor which maybe carried through the tubes 23 and 24 from the lower drum 20. This evaporation in the upper drum prevents the assage of wet vapor or liquid refrigerant to t e compression mechamsm.-

Any oil or other lubricant which may be carried over into the evaporator from the compression device is forced through the coil 10 with the refrigerant, and enters the lower header 20. The lubricant employed may be lighter than the liquid refrigerant, or may be soluble therein as desired. It is' preferred to employ suflicient refrigerant in the s stem so that at least some refrigerant is in iquid form within the header 20 while the compressor is in operation, and the boilin or 'gasification of this l quid forms the oil mto a foam which is readily drawn up through the tubes 23 and 24 and the upper header 22, and through the pipe 25 to the compressor. If, for any reason, a considerable amount of lubricant should collect in the lower header 20, it will be drawn back to the compressor as soon as the level thereof reaches the tubes 23 and 24. This condition will not exist so long as there is liquid refrigerant in the lower header to convert the lubricant into foam.

The described evaporator may be employed in a refrigerating system without any .re ceiver or other storage chamber for reserve refrigerant, or may be employed with a re? ceiver as hereinafter described.

Referring now more part cularly to the modification of the invention shown in Figs. 4, 5, and 6, this evaporator includes a refrigerant receiver R mounted as a unitary part of the evaporator structure, and supported therewith within a refrigerator cabinet 18'.

The evaporator E employed in this modification is of the samegeneral construction as that described above, and a. detailed description thereof will not be repeated. The parts of the evaporator E in the modification of Figs. 4, 5, and Gare designated by the same reference characters as those designating like parts in Figs. 1, 2, and 3.

The receiver B may take various forms, and in general comprises a container for the coinparat vely warm liquid and gaseous refrigerant discharged from the condenser of the system. 'The receiver forms a part of the high pressure side of the system, and, accordingly, suitable expansion means such as an expansion valve, a float valve, or a capillary tube, are provided between the outlet of the receiver and the inlet of the evaporator.

In the disclosed embodiment, a receiver R of improved design is employed, this reported in any suitable manner, but is preferably disposed in a vertical position behind the rear end of the evaporator E, and is secured to the extended ends of the side stra s 12 thereof by tinning, soldering, or welding The ex 'ansion valve structure, nerally indicate at V, is sealed to and firms a closure for the lower end of the receiver casing 36. The expansion valve may take various forms, but is preferably de- I signed to be operated in accordance with the difference between the evaporator pressure and the pressure of an adjustable spring.

The disclosed expansion valve V comprises a cylindrical casing 38 havingan integral transverse upper wall 39. The outer wall of the casing 38 is sealed to the'lower end of the receiver casing 36 which may be looked over an annular extension on the valve casing, as shown at 40. A valve seat member 41 is m clamped and sealed in an o ening through the partition 39 by means 0 a va ve' chamber member 42 threaded to the lower end of the member 41. A gasket 43 may be dis posed between the valve seat member and the is partition 39, and a fine mesh wire screen 44 1s preferably secured over the upper end of the opening 45 through the seat member as shown. The member 42 has a cylindrical valve guiding extension 46 in which is slidably mounted a valve guide 47 carrying a valve plu or needle 48 at the upper end thereo The guide 47 and plug 48 are biased uplwardly by the valve closing sprin 49', w ich is compressed between the gui e 47 and the lower end of the extension 46. The valve plug 48 is aligned with the valve seat 50 in the member 41, and cooperates therewith to control the flow of refrigerant through the opening 45.

A valve operating lever 51 is ivotally secured to the member 42 and exten sjwithin a transverse opening therein. The inner end of the lever 51 pivotally engages the valve plugl 48, and the outer end 52 thereof rests on t e upper or free end of a flexible bellows 53. The lower end of the bellows 53 is sealed to the casing 38 about a central opening 56 in the lower end thereof, and a tubular member 54 extends within the bellows 53 and is provided with an integral flange 55, which is locked and sealed to the opening 56. A spring 57 is carried within the member 54, and is compressed between thef'inner surface of the upper end of the bellows. and an adjustable\ lug 58. The plug 58 threadedly engages t e interior of the member 54 and is provided with a slot 59 or other suitable tool engaging means to permit the adjustment of the tension on the spring 57 from the exte- 5 rior of the device. An outlet pipe 60 is sealed to an opening near the bottom of thecasing 38, and communicates with the inlet end of the evaporator coil 10.

The'expansion valve operates in-the usual 35 and well known manner to control the flow 53 acts through the lever 51 to move the plug 4 therein is lowered and the sprin 57 expands bellows 53 against the lowere evaporator pressure within the casing 38. The bellows 48 away from its seat 50, and liquid re rigerant, which has collected within the receiver casing 36 from the condensing means of the system, is permitted to flow through the valve and the valve casing 38 and enters the evaporator coil 10. The liquid refrigerant exw pands within the evaporator and evaporates to give the required heat absorbing effect. The rate at which liquid refrigerant is admitted to the evaporator is governed in accordance with the evaporator pressure, and after the compressor stops and the evaporator pressure builds up to a predetermined value, the bellows 53 is compressed by this pressure, and the spring-49 closes the valve.

The modification of Figs. 4,5, and 6 is preferably provided with means for insuring the complete evaporation and drying of the gaseous refrigerant drawn to the compressor from the evaporator. This means takes the form of a coil of pipe 61 or other suitable conduit which is disposed in heat exchanging relation to the receiver R, and

which acts as the outlet pipe for conducting refrigerant from the upper header 22 of the evaporator to the suction line of the compression mechanism. As shown, the coil 61 is disposed in vertical loops about the receiver R in close proximity thereto, and this pipe may be tinned to the surface of the receiver casing 36, if desired. The outlet pipe 62 of the coil 61 is connected to the suction line of a suitable compressor, which compressor discharges compressed refrigerant gas into suitable condenser means connected to deliver condensed refrigerant to the receiver R.

The gaseous refrigerant leaving the evaporator is at a considerably lower temperature than is the condensed refrigerant entering the receiver R from the condenser, and hence considerable heat is absorbed from the refrigerant in the receiver casing 36 by the refrigerant in the coil 61. This lowers the temperature and pressure of the refrigerant in the receiver, and increases the efiiciency of evaporation in the evaporator E. Further, the heat delivered to the refrigerant in the coil 61 converts any wet vapor therein into gas and assuresthe delivery of dry gas only to the compression mechanism. A further advantage derived from the cooling of the compressor, the cooling of this casing by the coils cl materially reduces the head pressure on the high pressure side of the-system. This is particularly advantageous in ly reduces the starting and operating load on the compressor andthe driving means ceiver in a vertical spiral as shown at 78 in Fig. 10, and in this case the inlet pipe 77 of, the receiver is preferably connected to the top of the receiver casing 79 as shown; It is obvious that the coil may be disposed in any desired relation to the receiver, and that the invention is not limited to the specific arrangements shown.

As noted above, the expansion means eInployed to control the flow of refrigerant from the receiver to the evaporator may take any suitable form, such as a float valve or a capillary tube. In Fig. 11, the receiver R has been shown provided with a float valve to maintain the required difference in pressure at this point. The receiver R of Fig. 11 includes a casing 63, to which a liquid refrigerant pipe 64 from the condenser is sealed. The float valve structure, generally which is sealed to and acts as a closure for the lower end of the casing 63. The valve structureincludes a seat member 66 threaded tion with a duct 67 through the base plate 65. An upwardly extending valve guiding member 68 is formed integrally with or suitably secured to the seat member 66 and carries a vertically slidable valve plug or needle 69, disposed for cooperation with a seat '70 in the member 66. A lever 71 is pivotal 1y connected to the member 68 and to the upper end of the valve needle 69, and the outer end of this lever is pivotally secured to the depending rod 72 of a float 73. A guide lever 74 is pivotally connected between the lower end of the rod 72 and the member 68 as shown When liquid refrigerant collects within the casing 63 of the receiver R and rises to the level of the float 73, the float is lifted and acts through the lever 71 to lift the valve needle 69 from its seat 70. This admits liquid refrigerant through the restricted passage of the valve seat 70, the duct 67 and the pipe 75 to the coil 10 of the evaporator E.

The receiver R of Fig. 11 is preferably surrounded by a coil 76, which acts to conduct refrigerant from the evaporator E to the suction line of the compressor. The coil 76 is disposed in heat exchanging relation to the receiver R, and acts to reduce the temperature and pressure of the refrigerant in the receiver as well as to insure the delivery small domestic installations, as it material may be wound about the'casing of the re indicated at F, is carried by a baseplate 65,

or otherwise suitably secured in communicaof dry gas only to the compressor, as explained above.

In a modified form of the invention as shown in Figs. 7, 8, and 9, improved means are provided for rapidly absorbing heat from the trays 27, and quickly freezing the contents thereof. This means comprises a pipe or other conduit carrying evaporating refrigerant, and disposed within the freezing compartment 26', and in contact with the trays 27' therein. As shown in the drawings the evaporator E is of the same general orm as that disclosed in Figs. 1, 2 and 3, having a horizontally disposed coil the discharge end 21' of which is connected with a lower header which is in turn connected with an upperheader 22, the headers being disposed horizontally and in spaced relation within the confines of the coil 10. The headers 20' and 22 are connected by the tubes 23' and 24' as shown, and a receiver B may be secured to the rear end of the evaporator E" in -the manner explained above in connection with the modification of Figs. 4, 5 and 6. The receiver B may include an expansion valve, a float valve, or other suitable pressure reducing means, and the inlet pipe 37' thereof is connected to receive condensed refrigerant from the outlet of the condenser of the system. When a receiver is employed in connection with the evaporator E", the outlet of the evaporator preferably includes a pipe61' disposed in heat exchanging relation to the receiver R for the purpose explained above.

. The outlet pipe 80 leading from the expansion means in the receiver R is connected to a freezing pipe 81 within the freezing chamber 26 through a fitting 82 as shown in Fig. 8.

The pipe 81 extends horizontally along one.

side of the freezing chamber 26 to a point near the front end-thereof, then bends downwardly and returns ina second horizontal section 83 to the rearward end of the chamber, from which poin't it bends downwardly and inwardly to the bottom of the chamber as shown at 84. The freezing pipe then forms a horizontal loop 85 on the bottom of the freezing chamber 26', returning to the rearward end of this chamber and passin upwardly and outwardly as shown at 86. rom this point the pipe extends horizontally to the front end of the freezing chamber 26 in a section 87, and then returns in a horizontal section 88, parallel to and in horizontal alignment with the section 81. The rearward end of the section 88 is connected with the inlet end of the evaporator coil 10 through a fitting 89. The upper freezing tray 27 is slidably supported on the two uppermost sections 81 and 88 of the freezing pipe, and the lower tray rests upon the lower loop 85 of this pipe as shown in Fig. 9. The sections 83'and 87 of the freezing pipe lie in close proximity to the sides of the upper tray, and the diagonal'sections 84 and 86 lie close to and may contact with the rearward end of the lower ing trays 27 are in direct contact with a section of pipe within which the refrigerant is evaporating, and consequently heat is absorbed from the trays at a very rapid rate, and the temperature of the contents thereof is quickly lowered. The freezing pipe may comprise the initial section of the evaporator which receives refrigerant directly from the expansion means as shown, or this pipe may be connected at any other point in the evaporator circuit. It should be noted that with the quick freezing arrangement, as well as in the other modifications of the invention, a single large tray 19 may be substituted for the two small trays 27 the tray 19 being suported by its upper rim or flange upon the upper sections 81 and 88 of the freezing pipe as shown in Fig. 9, or resting'on the lower section 85.

It should be understood that the invention is not limited to the s ecific constructions shown in the drawings, ut includes all such modifications thereof as fall within the scope of the appended claims. Thus,- the evaporator E of Figs. 1, 2, and 3, as well as the evaporator E of Figs. 7, 8, and 9, may be employed either with or without a recelver, and the improved expansion means and receiver of the invention may be employed with either type of evaporator, or may be disposed at a point remote from the evaporator and outside of the refrigerator cabinet, as desired.

We claim:

1. An evaporator for refrigerating systems comprising a continuous coil of pipe,

a header and a second header positioned above said first header, all connected in series in the order named.

2. An evaporator for refrigerating systems comprising a continuous coil of pipe, a pair of vertically spaced interconnected headers enclosed within said coil and means for connecting one end of said coil of pipe to one of said headers.

3. An evaporator for refrigerating systems comprising a. coil of pipe, a lower header, and an upper header positioned above said lower header, said coil and said headers being connected in series and said headers being disposed within said coil with a freezing compartment therebetween. 4. An evaporator for refrigerating sys-' tems comprising a continuous coil of pipe enclosing a compartment, a lower header within said coil near the lower end of said compartment and connected to one end of said coil of pipe, an upper header within said coil and vertically spaced from said lower header and means for connecting said upper header to said lower header.

5. An evaporator for refrigerating systems comprising a continuous coil of pipe arranged to enclose a compartment, an upper header and a lower header mounted inside of said compartment in spaced relation, said lower header being connected to one end of said coil of pipe and to said upper header.

6. An evaporator comprising in combination a coil of pi e and a liquid refrigerant receiver arrange end to end, and a pair of headers supported within said coil of pipe, said coil being connected at one end to said receiver and at its other end, to one of said headers, means connecting said headers, and a discharge pipe connected with the other header and-arranged in heat exchanging relation with said receiver.

7/ An evaporator comprising in combination 'a-coil of pipe and a liquid refrigerant receiver arranged end to end, a pair of spaced headers supported within said coil of pipe, said coil being connected at one end to said receiver and at the other end to one of said headers, means for connecting said headers, a second pipe connected with the other of said headers and disposed in heat exchanging relation with said receiver, and bracing means for engaging said pipes and said receiver for producing a unitary rigid construction.

8. An evaporator comprising in combination a coil of pipe and a liquid refrigerant receiver arranged end to end, a pair of spaced headers supported within said coil of pipe, said coil of pipe and said headers forming a freezing compartment, said coil-being connected at one end to said receiver and at the other end to one of saidheaders, means for connecting said headers, a second pipe connected with the other of said headers and disposed in heat exchanging relation with said receiver and means within said freezing compartment for supporting removable liquid containers.

9. An evaporator comprising a continuous coil of pipe disposed to define a freezing compartment within the confines thereof, a pair of vertically spaced interconnected headers within said compartment, one end of said coil of pipe being connected to one of said headers, a section of pipe connected to the other end of said coil and disposed within said compartment and at least one liquid container removably supported within said compartment by said pipe section and in direct contact therewith.

10. An evaporator comprising a coil of pipe disposed to enclose a freezing compartment, a liquid refrigerant receiver adjacent one end of said compartment,-a section of pipe connected between said receiver and said coil and disposed within said compartment, at least one removable liquid container disposed within said compartment and su ported by and in direct contact with sai pipe 7 being connected in series and said headers section, and a discharge pipe connected to said coil and disposed in heat exchanging relation with the receiver;

11. An evaporator comprising a horizontal coil of pipe disposed to enclose a compartment, a refrigerant receiver mounted adjacent one end of said coil, pressure reducing means mounted in said receiver, means for connecting one end of said coil to said receiver through said pressure reducing means, and conduit means connected to the other end of said coil and passing in heat exchanging relation to said receiver.

12. A combined refrigerant receiver and expansion means for regrigerating systems, comprising a casing having an opening therein, a pressure chamber having a wall thereof sealed across said opening, and an expansion device carried by said pressure chamber and acting to control the flow of refrigerant from said casing.

13. A combined refrigerant receiver and expansion means for refrigerating systems comprising an elongated casing having an opening at one end thereof, a valve casing sealed in the opening in said elongated cas ing, a pressure operated expansion valve within said valve casing for controlling the flow of refrigerant from said elongated casing to said valve casing, and means accessible from the exterior of said valve casing for adj usting said valve.

14. An evaporator for refrigerating systems comprising a continuous coil of pipe, a pair of spaced interconnected headers enclosed within said coil and means for connecting one end of said coil of pipe to one of said headers.

15. An evaporator for refrigerating systems comprising a coil of pipe, a pair of spaced headers, said coil and said headers being disposed within said coil with a freezing compartment therebetween.

In testimony whereof we aflix our signatures.

HAROLD W. WISHART. ROBERT L. ALEXANDER.

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