US2481968A - Refrigerant flow controlling device - Google Patents

Description

2,48L9fi His Attorney- Inventor. Leonard WAtchison, 1 62 h,; 7. 0 4 1 Filed Aug. 10, 1946 L W ATCHISON REFRIGERANT FLOW CONTROLLING DEVICE Patented Sept. 13, 1949 REFRIGERAN T FLOW CONTROLLING DEVICE Leonard W. Atchison, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application August 10, 1946, Serial No. 689,707 7 Claims. (01. 62-127) My invention relates to mechanical refrigerating systems employing fixed restrictors for controlling the flow of refrigerant to the evaporator and is particularly directed toward the prevention of the clogging of such restrictors by the freezing of water therein.

It has been found that extended operation of refrigerating systems employing a hermetically sealed motor compressor unit may result in the formation of small quantities of water in the refrigerating system. This water may arise, for example, from the heating and charring of the cotton insulation of the motor during such extended operation. Where a fixed restrictor, sometimes referred to as a capillary tube," is employed, this small quantity of water may freeze in the tube, clogging it and stoppingthe flow of refrigerant. In such event the refrigerating system cannot operate until the ice has been removed. It is an object of my invention to provide means for preventing clogging of the restricting tube.

It is another object of my invention to prevent I clogging of the restricting tube by maintaining a sufficiently high pressure in the restricting tube that the temperature of the refrigerant and any other liquid therein will be above the freezing point thereof. v

It is a further object of my invention to provide a flow-contro.1ing device for liquid refrigerant in which any ice formed is automatically removed.

Further objects and advantages of my invention will be apparent from the following description and the features of novelty which characterize my invention will be pointed out with particularity in the claims forming a part of this specification.

For a better understanding of my invention reference is made to the accompanying drawing of which Fig. 1 represents a front elevation partly in section of a household refrigerator embodying my invention; Fig. 2 is an enlarged view of one form of the flow-controlling device which is the subject of my invention; Figs. 3, 4, and 6 are modifications showing different forms of this flow-controlling device.

Referring to Fig.' 1, the household refrigerator illustrated includes a cabinet i having a food storage compartment 2 cooled by an evaporator 3 of the flooded type. A refrigerant liquefying unit 4 is mounted within a housing 5 on the top of the cabinet. This refrigerant liquefying unit comprises a hermetically sealed casing 5, which contains the motor-compressor unit, and a condenser I. The refrigerant is compressed by the motorcompressor unit and the compressed refrigerant passes through a conduit a to the condenser I, where it is liquefied. The liquefaction is accomplished by the circulation of air over the condenser 1 by a fan (not shown) driven by a motor 9 or any other suitable apparatus. The liquefied refrigerant passes from the condenser through a restricting tube ID to the flow controlling device I I. From the outlet of the device H the refrigerant passes through the conduit l2 to the evaporator 3. The refrigerant which is vaporized in the evaporator is withdrawn from the header l3 through a suction line H, the vaporized refrigerant passing through this line to the compressor. The suction line H and the greater portion of the restricting tube ID are secured together in heat exchange relation to insure vaporization of any liquid refrigerant which may be present in the suction line.

The restricting tube is employed in many mechanical refrigeration systems to provide for the maintenance of a pressure differential between the condenser and the evaporator. The pressure at the evaporator end of the restricting tube in such systems may be sufficiently low that vaporization of the refrigerant frequently induces the temperature below the freezing point of water. This reduction in temperature results in freezing any water present in the refrigerating system and in the collection of ice near the outlet end of the restricting tube. The flow-controlling device Ii makes possible the maintenance of sufficiently high pressure on the liquid in the restricting tube so that the temperature even at the outlet end thereof will be maintained above the freezing point of any water present. Hence, clogging of the restricting tube will be effectively prevented.

Referring now to Fig. 2, the embodiment of the flow-controlling device I l shown in this figure includes a housing composed of two parts 15 and IS. The member i5 is made of a material of relatively low heat conductivity, such as stainless steel, so that heat will not be readily Withdrawn from the outlet end of the restricting tube due to any freezing temperatures resulting within the valve. Between these two housing members l5 and I6 is clamped a flexible diaphragm I! having an opening la in the center thereof. The housing members l5 and i 6 and the diaphragm I! are held in assembled relation by bending the upper end of member It as shown in Fig. 2. A valve or closure member l9 spring biased by spring member 20 cooperates with the opening l8 to control the flow of refrigerant. The spring member 20 is selected to exert suflicient bias on the valve 3 member l9 that the pressure on the refrigerant in the restricting tube i will be high enough to maintain the temperature at a value above the freezing point of water. The diaphragm i1 is made of a flexible material so that any ice which may form thereon will be removed by the flexing resulting upon operation of the valve. Further, should the valve member l9 at any time become frozen to the flexible diaphragm I! by the formation of ice around the opening I8, the pressure on the condenser side of the diaphragm I! will soon build up to several times the normal pressure. This will result in a substantial flexing of the diaphragm II. The ice will thereby be removed, and the valve will immediately return to its normal operation.

In the alternate form of my invention, shown in Fig. 3, a housing composed of two parts 2| and 22 is employed, the part 2|, like the element IS in the preceding figure, being composed of a material of relatively low heat conductivity. Between the two parts of the housing are clamped a flexible diaphragm 23 and a resilient member 24 separated by a spacer ring 25. These parts are held in assembled relation by bending the upper end of member 22, as shown in Fig. 3. The flexible diaphragm 23 has a central opening 26. The valve or closure member 21 is held between the flexible diaphragm 23 and the resilient member 24, cooperating with the aforementioned opening 26 to control the flow of refrigerant. The resilient member 24 biases the valve member 21 to its closed position and the valve can open only when a predetermined pressure has developed on the restricting tube side of the valve. This insures the maintenance of a sufficiently high pressure on the liquid in the restricting tube. In the arrangement shown in Fig. 3 the temperature at the outlet end of the restricting tube ID will be maintained above the freezing point of water, whereas the temperature in the space between flexible diaphragm 23 and resilient member 24 may be substantially lower than 32 F. As in the construction shown in Fig. 2 the diaphragm 23 is made of a flexible material so that any ice forming thereon will be removed in the manner previously described in connection with Fig. 2.

The embodiment of my invention shown in Fig. 4 differs from that disclosed in.Fig. 3 only in the construction of the two members forming the housing. In this embodiment the two housing members 28 and 29 are provided with downwardly extending portions 30 and 3| which may be secured together in any suitable manner.

Another form of my invention is shown in Fig. 5. This includes a valve housing 32 having a threaded portion 33. A plug 34 screws into this threaded portion to close the end of the valve housing. The housing is provided with a seat 35 with which a weighted valve or closure member 36 cooperates. The plug 34 is provided with a central bore 31 which cooperates with a projection 38 of the weighted valve member to guide the valve member centrally within the housing 32. The weight of the valve member is so chosen that a pressure will be maintained on the liquid in the restricting tube l0 sufficient to keep the temperature therein above the freezing point of water. I

In Fig. 6 I have shown a modification of the weighted valve construction illustrated in Fig. 5. In the modification shown in Fig. 6, a flexible diaphragm 39 similar to those shown in Figs.

Lil

2, 3, and 4 is provided. This flexible diaphragm is held in position between two parts 40 and 4| of the valve housing. The housing assembly is completed .by a plug 42 which screws into the end of part 40. The part 40 is made of the material of relatively low heat conductivity for the same purpose as discussed in connection with Figs. 2, 3 and 4. The flexible diaphragm is provided with a central opening 43 which serves as a seat for the weighted valve or closure member 44, the valve member cooperating with this seat to control the flow of refrigerant. Any ice which may form on the diaphragm will be removed by the operation of the valve in the manner previously described in connection with Fig. 2.

While I have illustrated my invention in connection with a specific type of refrigerating machine, it will be obvious that it can be applied to any type of mechanical refrigerating system which employs a restricting tube. Also, while I have disclosed specific structures illustrating my device, I do not desire my invention to be limited to these particular embodiments and I intend by the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a refrigerating system, an evaporator, a restricting tube for conducting refrigerant to the evaporator, means for preventing freezing of liquid within said restricting tube including a flowcontrolling device between said tube and said evaporator, said flow-controlling device including a flexible diaphragm having an opening therein, and a movable closure member for said opening adapted to engage said diaphragm, said closure member being biased to maintain a pres sure on the liquid in said restricting tube sufficient to prevent freezing therein.

2. In a refrigerating system, an evaporator, a restricting tube for conveying refrigerant to said evaporator, means for preventing freezing of liquid within said restricting tube including a flowcontrolling device between said tube and said evaporator, said flow-controlling device including a flexible diaphragm having an opening therein, and a resiliently mounted movable closure member adapted to engage said diaphragm, said closure member being resiliently biased to maintainsuificient pressure on the liquid in said tube to prevent freezing therein.

3. In a refrigerating system, an evaporator, a restricting tube for conveying refrigerant to the evaporator, means for preventing freezing of liquid within said restricting tube including a flowcontrolling device between said tube and said evaporator, said flow-controlling device including a housing having a portion of low heat conductivity material, a flexible diaphragm within said housing having an opening therein, and a resiliently mounted movable closure member adapted to engage said diaphragm, said closure member being resiliently biased to maintain sufficient pressure on the liquid in said tube to prevent freezing therein.

4. In a refrigerating system, an evaporator, a restricting tube for conducting refrigerant to the evaporator, means for preventing freezing of liquid within said restricting tube including a flowcontrolling device between said tube and said evaporator, said flow-controlling device including a flexible diaphragm having an opening 7 therein, and a movable closure member adapted to engage said diaphragm'for controlling flow of refrigerant through said opening, said member being gravity-biased for maintaining a pressure on the liquid in said tube sufficient to prevent freezing therein.

5. In a refrigerating system, an evaporator, a restricting tube for conducting refrigerant to the evaporator, means for preventing freezing of liquid within said restricting tube including a fiowcontrolling device between said tube and said evaporator, said flow-controlling device including a housing, said housing being constructed at least in part of a material of low heat conductivity to minimize withdrawal of heat from said tube, a' flexible diaphragm within said housing having an opening therein, said diaphragm being adapted to flex to remove any frozen liquid formed thereon, and a movable closure member for-said opening adapted to engage said diaphragm, said closure member being gravity-biased to maintain sufficient pressure on the liquid in said tube to prevent freezing therein.

'6. In a refrigerating system, an evaporator, a restricting tube for conducting refrigerant to the evaporator, means for preventing freezing of liquid within said tube including a flow-controlling device between said tube and said evaporator, said flow-controlling device including a flexible diaphragm having an opening therein, and 'a movable closure member adapted to engage said diaphragm for controlling the flow of refrigerant through said opening, said closure member being 6- biased against said diaphragm for maintaining sufficient pressure on the liquid in said tube to prevent freezing therein, said flexible diaphragm being adapted to flex during the normal operation of said valve to remove any frozen liquid formed thereon.

- 7. In a refrigerating system, an evaporator, a restricting tube for conducting refrigerant to the evaporator, means for preventing freezing of liquid within said tube including a flow-controlling device between said tube and said evaporator,

said flow-controlling device including a flexible REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,380,787 Ellmauer June 7, 1921 1,891,357 Peltier Dec. 20, 1932 2,166,908 Philipp July 18, 1939

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