US2893219A

US2893219A - Refrigerating system and thermostatically operated control means therefor

Info

Publication number: US2893219A
Application number: US614849A
Authority: US
Inventors: Samuel G Eskin
Original assignee: Dole Valve Co
Current assignee: Dole Valve Co
Priority date: 1956-10-09
Filing date: 1956-10-09
Publication date: 1959-07-07
Anticipated expiration: 1976-07-07

Description

July 7, 1959 s. G. ESKIN REFRIGERATING SYSTEM AND THEIRMOSTATICALLY OPERATED CONTROL MEANS THEREFOR Filed Oct. 9. 195a FIG. 2 INVENTOR 5AMUEL G. E5KIN by 5%: ww ATTORNEYS REFRIGERATING SYSTEM AND THERMOS TATI- CALLY OPERATED CONTROL MEANS THERE- FOR Samuel G. Eskin, Chicago, Ill., assiguor to The Dole Valve Company, Chicago, 111., a corporation of Illinois Application October 9, 1956, Serial No. 614,849

3 Claims. (Cl. 62-22Z) This invention relates to improvements in refrigerating systems and apparatus.

Heretofore, closed refrigerating systems have used capillary tubes in the form of restrictors to provide a sufficient pressure drop in the refrigerant to effect boiling of the refrigerant in the evaporator to absorb the latent heat of vaporization and thus produce refrigeration at the evaporator. Due to the simplicity and lack of moving parts capillary restrictors have to a large extent replaced the more complicated expansion valves.

The capillary restrictors, however, due to their fixed passageways are not efiicient where the refrigerating system is subjected to a wide fluctuation in temperature and load, such as is encountered in room air conditioners in which there is a considerable variation in the outdoor temperature. t

In the usual refrigerating system, attempts have been made to increase the liquid flow of refrigerant as the load increases and to decrease the flow of refrigerant under light loads. However, in the refrigerating systems of room air conditioners, as the outside temperature increases, with a resultant increase in load on the system,

the pressure and the temperature of the refrigerant goes.

up. The compressor and its drive motor may then be so overloaded that the motor fuse will blow out and there will be no refrigeration when it is most needed.

In accordance with the principles of my invention, I provide a throttling valve in the refrigerant line to the evaporator and operate this throttling valve with a thermal element in direct contact with the refrigerant passing through the line, and so arrange the throttling valve as to reduce the flow of the refrigerant upon increases in pressure and temperature thereof as the load increases, and thus avoid overloading the compressor and the compressor motor to the extent that the motor fuse will blow. The compressor motor will therefore continue to operate upon extreme temperature conditions, the reduction in the flow of refrigerant maintaining the loadin balance with the capacity of the motor and its fuse.

A principal object of my invention, therefore, is to improve upon the present refrigerating systems, and particularly those adapted for use in air conditioners by reducing the compressor load upon extreme temperature conditions to balance motor load with the fusing of the energizing circuit therefor.

Another object of my invention is to provide a refrigerating system having a simpler form of flow regulator for feeding refrigerant to the evaporator, so arranged as to throttle the fiow of the refrigerant to the evaporator upon increases in condenser pressure and temperature of the refrigerant.

A further object of my invention is to accurately regulate the flow of refrigerant from the condenser to the evaporator of a refrigerating system, with a minimum amount of pressure variation on the low side of the flow regulator, as the pressure varies on the high side thereof, and to throttle the flow of refrigerant to the evaporator in accordance with the temperature of the refrigerant in ice the refrigerant line between the condenser and evaporator.

Still a further object of my invention is to provide a simplified form of refrigerant expansion device and liquid feed control including a uniform volume flow regulator in the refrigerant line in series with a throttling valve and thermal element for operating the same, to throttle the flow of refrigerant to the evaporator upon predetermined increases in temperature of the refrigerant effected by overload on the system.

Another and more detailed object of my invention is to provide a simple refrigerant feeding device for feeding refrigerant to an evaporator in accordance with the load on the refrigerating system and temperature of the refrigerant, in which a wax type of thermal element is in the path of flow of refrigerant from the condenser to the evaporator and is directly subject to the heat of the refrigerant as it enters the evaporator, and in which a throttling valve operated by the thermal element serves to reduce the flow of refrigerant to the evaporator as the temperature of the refrigerant and load on the refrigerating system increases, to maintain the motor load below the fusing capacity of the energizing circuit therefor.

These and other objects of my invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein:

Figure l is a diagrammatic view of a refrigerating system, illustrating one form in which my invention may be embodied; and

Figure 2 is a transverse sectional View taken through one form of refrigerant flow control and thermal sensitive feeding device which may be used to feed refrigerant to the evaporator in accordance with the principles of my invention.

In the embodiment of my invention illustrated in the drawing, I have shown a refrigerating system in which a compressor 10 driven by a motor 11, serves to compress a suitable refrigerant, such as, Freon or a like gas and supply the same to a condenser 12 through a pressure line 13 connected with the head end of the compressor. The refrigerant, condensed to a liquid in the condenser 12, passes through a pressure line 14 to and through a pressure responsive and temperature sensitive flow regulator and feeding device 15, for effecting a drop in the pressure of the refrigerant and accurately metering the same to an evaporator 16. The flow regulator and feed ing device 15 provides a sufiicient pressure drop of the refrigerant to effect boiling of the refrigerant in the evaporator, to absorb the latent heat of evaporation and thus produce refrigeration. It also is so arranged as to throttle the flow of refrigerant to the evaporator as the temperature of the refrigerant increases due to overload conditions, and in this mamier prevents loading of the compressor and motor over the capacity of the motor fusing. The evaporator 16 is connected with the suction side of the compressor it) through a suction line 17.

The motor 11 is energized through conductors 6 and 7 connected with a suitable source of power. A switch 9 is shown as being connected in the conductor 7 to start the motor 11. A fuse 8 is connected in the conductor 6.

The refrigerant feeding device and flow regulator 15 is shown in Figure 2 as including a resilient flow control device in the form of a resilient annulus 19, a thermal element 20, a throttling valve 21 operated thereby and a flow orifice 23 restricted by said throttling valve when the temperature range of the refrigerant reaches the operating range of the thermal element 20.

The resilient flow regulator or annulus 19 is shown as being seated against a metallic insert 24 seated in a shouldered passageway 25 leading through a connector 26.

The metal insert 24 has a central orifice 27 leading therethrough in registry with an orifice 29 leading through the resilient annulus or flow regulator 12* and of a larger diameter than the orifice 29.

The insert 24 may be pressed or otherwise secured to the shouldered passageway 25 and forms a flat seat for said fiow regulator in the shouldered passage 25.

The connector or fitting 26 has a connector 30 threaded on the inlet end thereof. The connector 30 may be a flared connector for sealing the inlet end of the pipe 14 leading from the condenser 12 thereto. Where required the fittings or connectors 3i) and 26 may be silver soldered to make a permanent gas tight connection.

The flow regulator or resilient annulus 19 has a concave downstream face 32 which progressively moves into engagement with the seat formed by the annular insert 24, upon increases in pressure on the upstream side of said flow regulator, to reduce the cross sectional area of the orifice 29, as the pressures increase, and thus to assure a uniform pressure drop on the low pressure side of the flow regulator 19, regardless of pressure variations on the high pressure side thereof.

The resilient annulus 19 may be made from a Neoprene compound, Buna N, Buna S, a Hycar base compound, or any other suitable material impervious to the action of the refrigerant and lubricant in the system.

The flow regulator 19 operates on principles similar to those shown and described in the patent to Clyde A. Brown, No. 2,389,134 and entitled, Flow Control Valve and on principles disclosed in the application of Robert R. Dahl, Serial No. 412,752, filed February 26, 1954 and entitled Flow Control Structure. It is, of course, understood that various other forms of resilient flow regulators may be used in place of the particular flow regulator shown.

Threaded within the fitting or connector 26 is a hollow fitting 33 having a chamber 34 therein leading to a reduced diameter outlet passageway 35. The chamber 34 contains the thermal element 20 as well as the valve 21. An orifice member 36 having the orifice 23 therein is shown as being threaded within the outlet passageway 35 in axial alignment with the valve 21.

The thermal element 20 is shown as being of the so called Wax or power type of thermal element such as is shown and described in the Vernet Patent No. 2,386,181 dated January 30, 1945. The present thermal element has been selected for its simplicity and compactness as Well as for its relatively long range of travel. in such forms of thermal elements, a thermally deformable medium (not shown) such as, a wax alone, or a wax a metal powder and a binder is contained in a casing 39 of the element and acts against a membrane or deformable member (not shown), to extend a power member or piston 37 from a cylinder 40, when the thermally deformable medium is heated to its fusion or operating range.

As herein shown, the casing 39 is surrounded by a metal ring 4i. which acts as a heat conductor and abuts the end wall of an annular retainer 43, secured to and extending from the insert 24. The annular retainer 43 has ports 44 therein, affording a means of communication from the passageway 27 to the chamber 34 and is so arranged as to assure the passage of the refrigerant around the casing 39, extending within the annular retainer 43.

The thermal element 2% is retained within the annular retainer 43 by a compression spring 45 seated at one end on a shouldered end wall 46 of the chamber 34, and at its opposite end against a flange 47, extending outwardly from the wall of a cup like portion 49 of the valve 21. The spring 45 forms a return spring for the valve 21 and the power member 37, as well as a means for retaining the valve to the power member 37 and retaining the thermal element in place within the annular retainer 43.

The valve 21 is shown as having a generally frustoconical face 50 extending outwardly from the cup like 4 portion 49 thereof. The frusto-conical face 50 terminates into a throttling or metering pin 52 extending therefrom for registry within the orifice 23 to throttle the flow of refrigerant, as the temperature of the refrigerant increases to the range of fusion of the thermally responsive medium within the casing 39.

The cup like portion 49 of the valve 21 as shown in Figure 2 as extending inwardly along the power member 37 and cylinder 40 in radially spaced relation with respect thereto, when the power member 37 is in its extreme retracted position. The power member 37 also abuts the end wall of the recessed portion of the cup like portion of the valve member 21 so as to move the metering pin 52 toward the orifice 23 as the temperature of the refrigerant reaches the range of fusion of the fusible thermally expansible material contained within the casing 39.

It should here be understood that the operating range of the thermal element 20 may be varied 'by using various forms of fusible materials within the casing 39, which will fuse at the selected operating range of the thermal element.

It should here be noted that the orifice member 36 has a slot 53 therein, affording a means for adjusting the position of the orifice 23 with respect to the metering pin 52 when the valve is in its retracted position. The length of travel required for the metering pin to register with the orifice 23 may thus be varied to vary the operating range of the thermal element 21, and the temperature at which the refrigerant will be throttled to reduce the delivery volume of the refrigerant fed to the evaporator 16,'and maintain the load on the compressor 10 and motor 11 to the capacity of the motor fuse 11, and thus avoid blowing the fuse of the motor upon extreme increases of temperature of the outside air, where the refrigerating system may be the refrigerating system of an air conditioner.

It should also be understood that the valve 21 serves only as a restn'ctor valve and never blocks the flow of refrigerant through the orifice 36. Thus, as the load on the motor and the pressure of the refrigerant decreases, the temperature of the refrigerant will also decrease. The spring 45 will then move the metering pin 52 away from the orifice 23 with a resultant increase in the flow area of the orifice and an increase in flow of refrigerant to the condenser and the compressor.

The casing 33 is shown as having a reduced diameter threaded end portion 55, the inner periphery of which forms the passageway 35. A pipe 56 is threaded on the threaded end portion 55 and is also threaded on the intake end of the evaporator 16.

All of the threaded joints may be silver soldered Where required to make a permanent gas tight connection, although they need not be soldered.

It may be seen from the foregoing that I have provided an extremely simple compact and efiicient device for the control of the pressure drop in a refrigerating system, and for maintaining the load of the refrigerating system in balance with the fusing of the motor 11, so as to eliminate the blowing of the motor fuse and the stopping of the refrigerating system at times when refrigeration is most needed.

It mayfurther be seen that this is attained by reversing the present practice of increasing the supply of refrigerant as the load increases, and instead reducing the refrigerant supplied to the evaporator as the load increases beyond the safe fusing load of the motor 11 and thus preventing the load on the compressor and motor from rising above the capacity of the motor fuses.

It may still further be seen that the simplicity, efiiciency and compactness of the refrigerant feeding device of my invention is attained by the use of a relatively small power or wax type of thermal element operating a throttlingvalve to reduce the flow of refrigerant to the evaporator asthe temperatures increase, and by the use of a, simple resilient annular flow control regulator effecting a uniform pressure drop of the refrigerant over a Wide variations of pressures of the refrigerant on the high pressure side of the flow control.

It will be understood that modifications and variations in the present invention may be effected without departing from the spirit and scope of the novel concepts thereof.

I claim as my invention:

1. In a refrigerating system having a closed refrigerating circuit including compressing means, condensing.

means and evaporating means and thermally controlled flow regulating and throttling means for feeding refrigerant to said evaporating means and including resilient annular deformable flow regulating means for metering the flow of refrigerant to the evaporating means and pro viding a substantially uniform pressure drop in the re frigerant over a wide range of variations in head pressure at the compressing means, and thermally operated throttling means in series with said flow regulating means and throttling the supply of refrigerant to said evaporating means upon excessive temperature conditions thereof.

2. In a refrigerating system having a closed refrigerating circuit including compressing means, condensing means and evaporating means, resilient annular deformable means for feeding refrigerant to said evaporating means and maintaining a substantially constant pressure drop of the refrigerant over a wide range of fluctuations of condenser pressures, and thermally responsive throttling means in series with said flow regulating means and having a thermal element in the path of the flow of refrigerant from said condensing means to said evaporating means and a throttling valve operable thereby and throttling the flow of refrigerant to said evaporating means when the temperature of the refrigerant reaches the operating temperature range of said thermal element.

3. In a refrigerating system having a closed refrigerating circuit including compressing means, condensing means and evaporating means, resilient annular deformable fiow regulating means for metering the flow of refrigerant from said condensing means and providing a substantially uniform pressure drop over a wide range of fluctuations in load on said condensing means, and a throttling valve in series with said flow regulating means and having a thermal element in the flow of refrigerant to said evaporating means and operable to throttle the flow of refrigerant to said evaporating means when the temperature thereof reaches the operating range of said thermal element.

References Cited in the file of this patent UNITED STATES PATENTS 1,782,651 Hoffman Nov. 25, 1930 2,319,498 Gerard May 18, 1943 2,439,336 Dillman Apr. 6, 1948 2,755,025 Bloes July 17, 1956 2,765,629 Schulz et Oct. 9, 19 56