US2675684A

US2675684A - Refrigerating apparatus

Info

Publication number: US2675684A
Authority: US
Publication date: 1954-04-20
Anticipated expiration: 1971-04-20

Description

April 20, 1954 M G SHOEMAKER 2,675,684

REFRIGERATING APPARATUS Filed Aug. 17, 1951 Patented Apr. 20, 1954 UNITED sinral oFFlcE REFRIGERATNG APPARATUS Malcolm G. Shoemaker, Doylestown, Pa., assignor to Philco Corporation, Philadelphia, Pa., a corporation of Pennsylvania 6 Claims.

The present invention 'relates to refrigerating apparatus and, more particularly, to `a refrigeration system and valve lmeans vtherefor which provides for vheating of the evaporator 'to ei'ect removal of frost which, during normal operation plcatin, Serial N0. 189,183, 'led October 9, 1950,

now Patent No. 2,631,441, issued lviarch 17, 1953.

In accordance with the `teachings of 'my abe-ve Videntied zo-pending application, deirosti'ng is a'cen'iplish'ed 'through the agency of a 'valve Structure disposed 'the suction line and having connection with the discharge side of the cor`npres'sor. This valve structure is adapted, through suitable passage means, to by-pass the main rior-f restrictor or capillary tube and, concurrently, to establish flow of refrigerant from said discharge side of the compressor, through the suction line and thence through the evaporator in a direction reverse with respect to the normal direction of flow through said evaporator. The system includes a continuously open return passage or connection which, under defrosting conditions, conducts liquid refrigerant flowing from what is ncrmally the inlet side vof Vsaid evaporator, direotiy back to the compressor.

It is an important object of the present invention to improve the construction and operation of the valve structure which 4is incorporated in a system of the above mentioned type to control the 'reversal of the ow of refrigerant through the evaporator. Broadly, this object ofthe ir'ivenw tion is realized by providing an improved valve arrangement which is associated "with the refrigeration system in a novel manner 'so as 'to operate directly in response to pressure conditions which are created in the system by initiation and termination of a defro'sting cycle. A valve arrangen ment constructed Yand used in accordance with this invention, has the advantage of doing away with the vneed of 'employing specially and 'accurateiy designed mechanical pressure applying and compensating means, such as a spring, to govern the actuation of the valve in its fiow controll'ing function. As a result, adequate operatio'n of the valve is assured and is not jeopardized by possible failure of mechanical vspring means.

The 'novel features of the invention and the manner in which the above are recited and other objects and advantages are best achieved, will 'clearly appear trom the following description 'of the embodiment "shown in the accompanying drawing, which:

Cil

Figure 1 is a diagrammatic representation of a refrigeration system including de'frost'ing apparaf tus embodying the present invention and showing the condition which exists in the system during a normal refrigerating cycle;

Figure 2 is a View similar to Figure 1, but shows the condition which exists in the system during 'a defrosting cycle; and

Figure 3 is an enlarged cross-sectional view of the pressure responsive valve constructed in accordance with the invention to control the flow "of refrigerant in the system illustrated in Figures l and 2.

With more particular reference to the drfawmg, the embodiment as illustrated in Figures 1 and I2, comprises the usual elements of a reirigeration system or conventional type, namely, Va motorcoinpressor lo, a condenser Il, and an evaporator i2. These elements are Vconnecfted `in series flo'w circuit through the agency of suitable connections and conduits, including iiow restrictor or vcapillary tube I3 and suction line it. A's 'is customary, the evaporator is disposed in heat exchange relation with a compartment or Zone to be cooled, said compartment or zone being diagrammaticallyshown by broken line C. Also, as is customary, the capillary tubeand the suction line may, if desired, be associated in heat eX- change relation. This y'association has* been omitted from the drawing in the interest oi siniplicity and clarity of illustration.

In addition to the above mentioned usual components, the system according to the inventior1,'

with the inlet of the 'evaporatoijat'itsjunctui-e with the outlet or" the iiow restri eterV orA capillary tube, and the other end connected with the suc'- tion line at a point Ybetween the motorcornpres'sor and the pressure responsive valve device. y

The solenoid valve device comprises a body l providing two chambers 2o and 2l which are adapted to communicate with each other through the opening 22 (see Figure 2') in 'a valve seat structure 23 which separates vsaid chambers. Communication between said chambers nore mally prevented (see Figure 1) by means ofk a valve element 24 in engagement with said seat 23e. The 'valve body i9 is provided with three ports 25. 25 and 21.

Ports

25 and 26 open into one chamber 2S of the valve body; one port 25 being connected with the outlet of the condenser, the other port 2t being connnected with the inlet of the capillary tube. The remaining or third port 2 opens into the other chamber 2| and is connected with the aforementioned connecting conduit I7 which leads to the pressure responsive valve device I6.

The pressure responsive valve device comprises an elongated body 28 which, as clearly seen in Figure 3, has a longitudinal bore 29 extending therethrough. One end of the valve body is provided with an enlarged portion 39 which is generally cup-shaped and is closed by means of a cap El. This cup-shaped portion and its cap cooperate to form a hermetically sealed housing enclosing a diaphragm 32 which stretches across said housing, the marginal edge portion 33 of said diaphragm being lixedly retained between at clamping surfaces 3d and 35 provided on said cup-shaped portion and cap, respectively. A valve stem 3l having one end rigidly affixed, as at 38, to the center of the diaphragm, depends from the latter and extends into the bore 29 in the Valve body. The valve stem is provided with a passageway 39 which, as shown at iii), is in open communication with space li defined by the valve cap and the diaphragm and which, as shown at d2, is also in open communication with a chamber 133. This chamber is conveniently formed by enlargement of a portion of said bore 29 and is in open communication with space dri defined by the cup-shaped portion and the diaphragm. For the purpose of establishing open communication between said chamber 43 and said space d4, the aforementioned bore 25 is of greater cross-sectional dimension than the cross-sectional dimension of the valve stem. The chamber 43 also communicates, as at d5, with another chamber 46 which is provided by a still greater enlargement of the internal bore in the valve body 28. The communication between chambers d3 and 46 is controlled by means of a valve element il which is provided on the valve stem 3l and which is adapted for engagement with a valve seat 48 between said chambers. The valve body is 'provided with three ports 49, and 5E; port 49 opens into chamber 43 and is connected with the suction line I d extending from the evaporator; port 50 opens into chamber d5 and is connected with the suction line portion indicated at I da which leads to the motor-compressor; and port 5I opens into space 44 and is connected with the conduit I which, as hereinbefore indicated, is connected with the valve controlled chamber 2| in the solenoid valve body.

Referring again to Figures 1 and 3, it will be seen that the system is conventional insofar as the normal refrigeration cycle is concerned. During such normal refrigerating cycle, the solenoid valve element 24, as seen in Figure 1, engages its valve seat 23, and the pressure valve element di, as seen in full lines in Figure 3, is moved away from its seat 48. Under these conditions, hot gaseous refrigerant is delivered from the compressor to the condenser where the compressed gaseous refrigerant gives up heat to the ambient air and is converted to liquid state. From the condenser, liquefied refrigerant passes into chamber 2o of the solenoid valve body I9 and thence flows through the capillary tube i3 and the evaporator I2 where the refrigerant vaporizes and, in the process, absorbs heat from air Within the oompartmentor zone C. Heat-laden `vaporized refrigerant which flows from the evaporator through suction line lli, passes through intercommunicating chambers 43 and is in the pressure valve body 28 and then flows through the suction line portion Ilia into the compressor. During the above described refrigeration cycle, no flow of refrigerant occurs through conduit I1 since this conduit is sealed-ol by the solenoid valve element 2d, and the flow through the pressure valve takes place through suction line section Id, intercommunicating chambers d3 and 65, and suction line section Ilia. Under these conditions, it will be understood that the pressure in chamber 153| determines the pressures which exist on opposite sides of the diaphragm since said chamber is in open communication with cavities or spaces il and M through bore 29 and passage- Vway 39, respectively. Thus the pressures which prevail in said chambers and in said cavities are substantially the same so that the diaphragm is maintained in neutral position and the valve element 4l tends to remain in open position as long as the normal refrigerating cycle is in progress, that is to say, as long as the condition represented in Figure 1 exists. It is pointed out that during this refrigerating cycle or condition, the continuously open by-pass connection I8 performs a useful function in that fiash gas from the capillary tube is returned to the compressor, rather than passing through the evaporator where such ash gas tends to reduce the effectiveness of the evaporator. As shown in the illustrated embodiment, separation of the flash gas is conveniently accomplished by means of a separator device 52 interposed at the outlet of the capillary tube, the inlet of the evaporator and the inlet of said by-pass conduit I3. It is ignicant to note that the conduit or connection I8 is made as a restrctor. In practice, the restriction of this conduit or connection is just sufcient to prevent liquid refrigerant passing out of the capillary tube from flowing backwardly through said conduit or connection, and to insure that such liquid refrigerant will flow through the evaporator as is required during normal refrigerating operation of the system.

When it becomes desirable or necessary to defrost the evaporator, the refrigerating cycle is terminated and a defrosting cycle is `initiated by mere actuation of the solenoid valve device to open the communication between chambers 2i! and 2i in the body I9 of said valve device. In the embodiment shown, actuation of the solenoid valve is accomplished through the agency of a solenoid coil 53 which operates to cause movement of the valve element 24 away from its seat. Operation of this solenoid coil can be obtained through suitable control mechanisms. Such mechanisms are generally known in the art and since the present invention is not concerned with them, illustration and description of their construction and operation is not required herein.

The condition which exists in the system during a defrosting cycle, is best understood by referring to Figures 2 and 3. The high pressure refrigerant emerging from the condenser into chamber 2o in the solenoid valve body I9-, passes into chamber 2l and out through conduit I'I into space 34 in the pressure valve body 28. The admittance of high pressure refrigerant into the space @il results in displacing the diaphragm 32, as is represented in broken lines in Figure 3. This displacement o f the diaphragm causes movement of the valve stem 37 which brings thevalve element 137 in engagement Withitsseatdd, therevby 'sealing communication between chambers 43 and Lit in the pressure valve body. From the space 44, the refrigerant passes through the bore 29 4about the valve stem into chamber 23 and, thence, enters the evaporator through line I4. In circulating through the evaporator, the gaseous refrigerant condenses thus providing the necessary heat for lmelting the frost accumulated on said surfaces. From the evaporator, the refrigerant returns through conduit I8 and suction line 'section [da to the compressor. It will be understood that in order to prevent mechanical diiiiculties due to liquid directly entering the compressor pump, the system utilizes the well known type of compressor in which the space Within the shell or dome of the compressor is included in the low pressure side of the system. By vusing this type of compressor, the refrigerant which is in liquid state, due to the condensation occurring within the evaporator during defrosting, is reconverted to gaseous state by heat exchange taking Vplace within the low pressure shell before entering the compressor pump. It is of importance to note that the restricted bore v29 impedes the flow of refrigerant which passes from of course, is that the opposite sides of the dia- -`fphragm 32 are subjected to the required pressure differential to insure maintenance of the valve in closed position, as is illustrated in broken lines in Figure 3, so long as the condition represented in Figure 2 exists.

When the defrost cycle is completed, the solenoid coil 53 is de-energized, for instance, by means of suitable known control (not shown), to move the valve element 24 in engagement with its seat. Seating of this valve element seals ofi the communication between chambers 2li and 2| and interrupts the fiow of high pressure refrigerant through conduit I1, whereupon the pressures on the opposite sides of the diaphragm equalize since sealing-off of said conduit cuts out the source of high pressure to cavity fill. The diaphragm then is free to return to its normal position and to release the Valve element 41 for movement to open position under influence of the pressure difference between chamber 43 and chamber 46. With opening of said valve element the pressures throughout the valve, that is the pressures in chambers d3 and t and in cavities 4l and B4, equalize and the normal refrigeration cycle is restored.

From the foregoing description, it will be appreciated that the present invention provides a defrosting system which is characterized by unusual constructional simplicity and operational reliability. Particularly, it will be appreciated that the peculiar construction of the pressure valve and its novel association in the system are significant features of the invention, and that these features make it possible effectively t0 control the refrigerating and the defrosting operations without having to depend on intricate mechanical means for such operations.

I claim:

1. Means operable to control the ow of refrigerant through the evaporator of a refrigera- 6 tion-system of the type having a compressor, condenser `and a restrictor in series ilow circuit vwith 'the evaporator, comprising a valve body having two intercommunicating chambers one of which is adapted for connection with the 'outlet of the evaporator `and the other of which is adapted for connection with the inlet of the compressor, a pressure operated diaphragm enclosed in said valve body, a valve member carried by said diaphragm and operable to establish and to prevent communication between said chambers, passage `means establishing communication between one side of said diaphragm and that one chamber 'which is adapted for connection with the outlet of the evaporator, other passage means establishing communication between the other side of the ydiaphragm and said one chamber, and selectively controllable conduit means communicating with said one chamber and adapted for connection with the condenser to establish communication between the latter and said one chamber.

'2. Control means as set forth in claim 1, in which the first mentioned passage means is constructed as a restrictor.

3. En combination with a refrigeration system of 'the type having a compressor, a condenser, a restrictor an evaporator; means operable to control the flow of refrigerant through the evaporator comprising a valve body having a first chamber 'connected with the outlet lof the evaporator and a second chamber connected with the inlet of the compressor, a pressure operated diaphragm enclosed in said valve body and cooperating with portions thereof to denne a first cavity to one side of said diaphragm and a second cavity to the other side of said diaphragm, a valve member connected with said diaphragm and normally positioned to establish communication between said chambers, rst means establishing open communication between said first cavity and said first chamber, second means establishing open communication between said second cavity and said first chamber, and selec-` tively controllable means operable to connect said first cavity with the condenser to provide for admission of refrigerant at high pressure in said cavity to cause movement of said diaphragm and valve to a position preventing communication between said chambers, said flrst means being so constructed as to impede the flow of refrigerant from said rst cavity to said first chamber to provide for reduced pressure in said chamber when the latter is connected with the condenser.

4. In combination with a refrigeration system of the type having a compressor, a condenser, a restrictor and an evaporator; means operable to control the now of refrigerant through the evaporator comprising a valve body provided with two intercommunicating chambers, one communicating with the outlet of the evaporator and the other communicating with the inlet of the compressor, a diaphragm enclosed in said body and cooperating with portions thereof to deiine a cavity to one side ci" the diaphragm and a cavity to the other side of the diaphragm, selectively controllable communication means between one of said cavities and the condenser, a valve stem attached to said diaphragm and provided with a passageway establishing communication between the other of said cavities and the said one chamber which communicates with the outlet of the evaporator, a valve seat between said chambers, and a valve element carried b-y said stem and operable in cooperation with said seat to establish and to prevent communication between V,adriatica said chambers through movement of the stem by actuation of the diaphragm in response to pressure conditions created on opposite sides of the diaphragm by operation of said selectively controllable communication means.

5. In combination with a refrigeration system of the type having a compressor, a condenser, a restrictor and an evaporator; means operable to control the iiow of refrigerant through the evaporator comprising a valve body provided with two intercommunicating chambers, one communicating with the outlet of the evaporator and the other Communicating with the inlet of the compressor, a diaphragm enclosed in said body and cooperating with portions thereof to dene a cavity to one side of the diaphragm and a cavity to the other side of the diaphragm, selectively controllable communication means between one of said cavities and the condenser, a valve stem attached to said diaphragm and provided with a passageway establishing communication between the other of said cavities and the said one chamber which communicates with the outlet of the evaporator, a valve seat between said chambers, a valve element carried by said stem and operable in cooperation with said seat to establish and to prevent communication between said chambers through movement of the stem by actuation of the diaphragm in response to pressure conditions created on opposite sides of the diaphragm by operation of said selectively controllable communication means, and a continuously open passage operable, when said valve element is moved to prevent communication between said chambers, substantially to by-pass the restrictor and to deliver refrigerant owing from the evaporator back to the inlet side of the compresser.

6. In a refrigeration system of the type having elements including a compressor, a condenser, a restrictor, an evaporator, and conduit means including suction and feed lines connecting said elements in series flow circuit, means operable to interrupt normal ow of refrigerant from the evaporator through the suction line to the compressor and to establish modied ilow of refrigerant from the discharge side of the compressor through said suction line and to the evaporator, said means comprising a valve body interposed between sections of the suction line and provided with two chambers one of which is connected with the suction line section leading from the evaporator and the other of which is connected with the suction line section leading to the compressor, a pressure operated diaphragm enclosed in said valve body, a valve member carried by said diaphragm and operable to establish and to prevent communication between said chambers, means in said valve body establishing communication between said one chamber and one side of said diaphragm, means in said valve member establishing communication between said other chamber and the other side of said diaphragm, and a continuously open passage operable, when said modified iiow is established, substantially to by-pass the restrictor and to deliver refrigerant owing from the evaporator back to the inlet side of the compressor.

References Cited in the file 0f this patent UNITED STATES PATENTS Number Name Date 1,863,427 Warren June 14, 1932 2,398,775 Beckley Apr. 23, 1946 2,451,385 Groat Oct. 12, 1948