US3626715A

US3626715A - Refrigeration component

Info

Publication number: US3626715A
Application number: US5006A
Authority: US
Inventors: Edward W Bottum
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-01-22
Filing date: 1970-01-22
Publication date: 1971-12-14
Anticipated expiration: 1988-12-14

Abstract

A SUCTION ACCUMULATOR IS PROVIDED FOR THE COMPRESSOR OF A REFRIGERATION SYSTEM WHICH INCLUDES A COMPRESSOR, AN EVAPORATOR AND A CONDENSER CONNECTED IN OPERATIVE RELATIONSHIP WITH REFRIGERANT EXPANSION MEANS BETWEEN THE CONDENSER AND EVAPORATOR. THE SUCTION ACCUMULATOR INCLUDES AN EVAPORATOR PRESSURE REGULATOR VALVE ON THE INLET WHICH IS A DEVICE SENSITIVE TO THE TEMPERATURE OF INCOMING EVAPORATOR GASES TO OPEN OR CLOSE IN ACCORDANCE THEREWITH

TO MAINTAIN THE PRESSURE-TEMPERATURE CONDITIONS OF THE EVAPORATOR AT A DESIRED LEVEL.

Description

Dec. 14, 1971 w, B T M 3,626,715

REFRIGERATION. COMPONENT Filed Jan. 22, 1970 INVENTOR. PEI Bj/W/r/A/ United States Patent O 3,626,715 REFRIGERATION COMPONENT Edward W. Bottum, 9357 Spencer Road, Brighton, Mich. 48116 Filed Jan. 22, 1970, Ser. No. 5,006 Int. Cl. F25b 43/00 US. Cl. 62217 3 Claims ABSTRACT OF THE DISCLOSURE A suction accumulator is provided for the compressor of a refrigeration system which includes a compressor, an evaporator and a condenser connected in operative relationship with refrigerant expansion means between the condenser and evaporator. The suction accumulator includes an evaporator pressure regulator valve on the inlet which is a device sensitive to the temperature of incoming evaporator gases to open or close in accordance therewith to maintain the pressure-temperature conditions of the evaporator at a desired level.

BACKGROUND OF THE INVENTION Automotive air conditioning systems have conventionally utilized expansion valves to provide expansion means for the liquid refrigerant from the high pressure side of the system to the low pressure side. In copending patent application Ser. No. 841,032, filed July 11, 1969, an air conditioning system which incorporates a capillary tube as the expansion device is disclosed. Either system preferably employs the use of a suction accumulator between the evaporator and the compressor.

The present invention provides a suction accumulator which incorporates an evaporator pressure regulator valve to control the pressure-temperature conditions of the evaporator to prevent evaporator freeze-up. Evaporator freeze-up is the condition when the evaporator coils are at a temperature low enough to freeze the moisture in the air passing thereover with the result that the evaporator coils become coated with ice which acts as an insulator thus reducing the effectiveness of the air conditioning system.

The evaporator pressure regulator valve is sensitive to temperature of incoming evaporator gases which are directly related to the pressure in the evaporator. When the temperature of incoming gases is too low, the valve tends to shut off flow from the evaporator thus causing the pressure in the evaporator to increase with a resultant increase in evaporator temperature to thereby avoid freeze-up.

Incorporation of the valve in the accumulator results in a cost saving as a result of integration of the valve in the accumulator, as a result of reduced installation costs and as a result of the less expensive valve casing which does not have to be made of corrosion resistant material such as copper, but may be made of steel because the valve is subjected only to contact with refrigerant gases. The accumulator is further advantageous in that any liquid resulting from actuation of the valve will flow directly into the accumulator rather than into the compressor of the system. The accumulator includes metering means for metering the flow of liquid to be compressor at a nonharmful rate.

SUMMARY OF THE INVENTION 3,626,715 Patented Dec. 14, 1971 let. A conduit within the casing extends from a point adjacent the bottom of the casing to the casing outlet. The conduit acts as a suction tube to draw liquid from the casing and expel it into the casing outlet at a metered rate. .An evaporator pressure regulator valve is provided on the inlet. This valve includes a valve element which is movable to open and closed positions. A temperature sensitive valve element actuator is positioned on the upstream side of the valve element for subjection to the incoming gases from the evaporator to move the valve element to the closed position when the temperature of the incoming gases falls below a pre-selected value and to move the valve element to the open position when the temperature of the incoming gases rises to a pre-selected value.

In the drawing:

FIG. 1 is an elevational view of a suction accumulator forming one embodiment of the present invention with portions broken away for the purpose of clarity;

FIG. 2 is a sectional view taken substantially along the line 22 of FIG. 1 looking in the direction of the arrows; and

FIG. 3 is a side elevational view of another embodiment of a suction accumulator with portions broken away for the purpose of clarity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The suction accumulators illustrated in the figures are adapted for use in connection with a vehicle air conditioning system which comprises the usual compressor, evaporator and condenser connected together in operative 'relationship. Capillary tube refrigerant expansion means are provided between the condenser and evaporator.

r Alternately, an expansion valve may be used between the condenser and evaporator. The suction accumulator is provided between the evaporator and compressor to trap any liquid refrigerant emanating from the evaporator and to feed this liquid refrigerant to the compressor at a metered rate. Flow is accomplished by means of the suction created by the compressor. The accumulator includes an evaporator pressure regulator valve which causes the evaporator pressure to remain at a minimum predetermined pressure which is selected so that the corresponding temperature thereof will not permit the evaporator to freeze. A vehicle air conditioning system of this type is disclosed in co-pending application, Ser. No. 841,032, filed July 11, 1969.

As illustrated in FIGS. 1 and 2, the suction accumulator 10 includes a casing 12 which comprises an openended tube 14 having an upper end closure 16 and a lower end closure 18 secured thereto as by brazing.

An outlet tube 20 extends through the upper end closure 16. The outlet tube 20 is U-shaped. One leg 22 of the tube 20 extends downwardly to a point adjacent the lower end closure 1-8. The tube is then provided with a bend 24 and a second leg 26 extends upwardly and terminates in an open end 28 adjacent the upper end closure 16. A small metering opening 30 is provided in the tube bend 24. Another opening 32 is provided in leg 22 at the upper end to equalize pressure in both of the

legs

22, 26. An inlet tube 34 also extends through the upper end closure 16. The inlet tube 34 extends for a short distance into the casing 12.

In operation of the accumulator cold refrigerant gas having a small amount of entrained liquid refrigerant therein is received from the system evaporator and enters the accumulator through the inlet tube 34. An evaporator pressure regulator valve 38, to be later described, controls flow of refrigerant from the evaporator. The refrigerant gases which enter the casing are drawn into the open 3 end 28 of the U-tube 20, pass through both legs of the U-tube and exit via the leg 22. The gases are passed from the U-tube 20 to the compressor of the refrigeration system (not shown). The compressor, which creates a suction, draws the gaseous refrigerant through the accumulator at a relatively rapid rate.

Liquid refrigerant which enters the accumulator through the inlet tube 34 drops to the bottom of the accumulator and is subsequently drawn through the opening 30 and thence through the leg 22 and out of the accumulator. It will be appreciated that the liquid which is metered into the leg 22 is entrained in the stream of gaseous refrigerant. It remains entrained in the gas as it passes from the accumulator and is drawn to the compressor of the system. The opening 30 acts as a restriction and causes liquid refrigerant to be metered into the compressor at a controlled rate. The accumulator thus acts to prevent large amounts of liquid refrigerant from suddenly entering the compressor. Such sudden surges of liquid may result in eriously damaging the compressor.

During operation of the refrigeration system in which the accumulator is installed, there are times when an unusual amount of refrigerant will collect in the accumulator. For example, when the system is shut off, such as is the case with an intermittently-operated air conditioning system such as an automotive air conditioning system, the refrigerant tends to condense in the entire system and collect in the accumulator. A similar situation may occur when the system is operated under low load conditions. The metering of the liquid refrigerant via the opening 30 results in liquid refrigerant being delivered to the compressor at a non-harmful rate.

Referring now to the evaporator pressure regulator valve 38, it will be noted that this valve comprises an outer tubular casing 40 which is of slighlty less diameter than the diameter of the inlet tube 34 and is received therein. The lower end of the inlet tube 34 has a spiderlike configuration with peripherally spaced apart downwardly depending members 42 which are secured at the lower ends thereof to a disc 44. The space between the members 42 permits flow of refrigerant from the valve 38 into the interior of the accumulator casing. At the same time, this structure sreves to support the valve 38 at a position interiorly of the accumulator casing. The upper end of the valve casing 40 extends into the solid portion 46 of the inlet tube. The casing 40 may be sealingly secured to the portion 46 as by brazing so that gases cannot escape around the valve and into the casing 12. Alternately, if it is wished to make the valve 38 easily removable, an O-ring may be used for sealing between the valve casing 40 and the inlet tube 34.

A slidable tubular valve element 48 is received within the casing 40. The valve element 48 is provided with spaced apart peripheral slots 50 in the side walls thereof. Similar slots 52 are provided in the sidewall of the valve casing 40. When the slots 50, 52 are in registry, fluid may pass through the valve 38 into the casing 12. When the slots 50, 52 are out of registry, as illustrated in FIG. 1, the valve is closed to the passage of refrigerant. The amount of refrigerant which will flow at any given time is determined by the degree of registry of the slots 50, 52.

A resilient bellows 54 is provided as the valve element actuator. The bellows 54 is charged with a volatile substance, for example, a refrigerant that is the same as that used in the refrigeration system, normally Freon-l2 in a vehicle air conditioning system. The bellows 54 functions according to the pressure-temperature relationship of the evaporator. Operation of the bellows, and thus the valve 38, is governed by the temperature of the refrigerant impinging upon the bellows. A rise in evaporator temperature will increase the temperature of the evaporated gas passing from the outlet of the evaporator to the inlet tube 34. The bellows 54 absorbs heat because of the fact that the charge in the bellows reacts in accordance with the pressure-temperature relationship, the pressure within the bellows decreases tending to move the valve element 48 to a position where the slots are out of register with the slots 52 of the valve casing 40. The greater the evaporator gas temperature rise, the smaller the valve opens and vice-versa.

The evaporator pressure regulator valve 38, which partially or completely closes when the pressure in the evaporator begins to decrease, causes the evaporator pressure to remain at a minimum predetermined pressure which is selected so that the corresponding temperature thereof will not permit the evaporator to freeze. As above mentioned, Freon-12 is the refrigerant most often used in vehicle aid conditioning systems. This refrigerant will boil at 2l.7 F. below zero at atmospheric pressure. In view of the fact that water freezes at 32 F., the temperature in the evaporator must be controlled so that water collecting on the core surface will not freeze and block air flow through the unit. In order to control the temperature, it is necessary to control the pressure inside the evaporator. To obtain maximum cooling effects, the refrigerant must remain in the evaporator long enough to completely vaporize. If insufficient refrigerant is present in the evaporator, cooling efficiency decreases. The evaporator pressure regulator valve is used to provide the necessary refrigerant pressure control to aid in preventing evaporator freeze-up and to aid in maintaining the efiiciency of the system.

A perforated strainer or screen 51 is provided in the casing 40 upstream of the valve 38 to capture any foreign matter which may be entrained in gases entering the casing 12. The use of a strainer is preferred to protect the working parts of the valve 38. Even small particles may cause valve failure by becoming entrapped between the valve casing 40 and valve element 48 and preventing proper movement of the valve element by the bellows 54.

FIG. 3 illustrates a modified suction accumulator 56. The accumulator 56 includes a casing 58 which is normally oriented with the longitudinal axis thereof in a vertical direction. The casing 58 comprises an open-ended tube 60 having an upper end closure 62 and a lower end closure 64 secured thereto as by brazing. A U-shaped outlet tube 66 extends through the upper end closure 62. The tube 66 has a configuration and function like that of the outlet tube 20 described in connection with FIG. 1 embodiment. A fusible plug 68 is provided in the lower end closure 64 as a safety device.

An inlet tube 70 extends through the sidewall of the tube 60. The portion 72 of the inlet tube 70 exterior of the casing 58 encloses an evaporator pressure regulator valve 38 of the same type as described in connection with the FIG. 1 embodiment. The inner end of the valve 38 abuts against a spider-like stop structure 74 whereby gases emanating from the valve 38 may pass into the casing 58. A peripheral flange 76 maintains the inner end of the valve 38 in the position illustrated.

The portion 72 of the inlet tube 70 has an enlarged diameter so that gases flowing from the slots in the valve 38 may exit into the portion 72 of the inlet tube and thence into the accumulator casing 58. The outer end 78 of the valve 38 is received in tube portion 80 of reduced diameter. An O-ring 82 is provided on the end 78 of the valve to sealingly engage the tube portion 89 and prevent passage of gas around the valve 38. Operation of the accumulator 56 is substantially the same as operation of the accumulator 10 as previously described.

A bimetal element may alternately be used to bring the slots into or out of registry.

With both the accumulator 10 illustrated in FIG. 1, with the evaporator pressure regulator valve 38 mounted internally of the accumulator inlet, and the accumulator 56 illustrated in FIGS. 3, with the valve mounted externally of the suction accumulator casing, a cost saving is effected. Not only is the valve integrated with the accumulator construction thus reducing manufacturing cost, but also installation cost is reduced because of the need of installing only one basic element and the valve may be constructed of, for example, steel, because the corrosion problem normally associated with such valves is eliminated as a result of the valve being subjected only to contact with refrigerant gases. Functionally, the accumulator structures illustrated are advantageous in that any trickle of liquid which is caused by the back pressure exerted by the valve flows into the accumulator and is metered to the compressor by means of the accumulator structure rather than flowing directly to the compressor without being metered, possibly resulting in damage to the compressor.

What I claim as my invention is:

1. In a suction accumulator for the compressor of a refrigeration system including a compressor, an evaporator and a condenser connected in operative relationship, refrigerant expansion means between the condenser and evaporator, said accumulator comprising a casing having an inlet conduit and an outlet, a conduit within the casing extending from a point adjacent the bottom of the casing outlet, said conduit acting as a suction tube to draw liquid from the casing and expel it into the casing outlet at a metered rate, an evaporator pressure regulator valve located entirely within said inlet conduit, said valve including a valve element movable to open and closed positions, and a temperature sensitive valve element actuator positioned on the upstream side of the valve element for subjection to the incoming gases from the evaporator to move the valve element to the closed position when the temperature of the incoming gases falls below a preselected value and to move the valve element to the open position when the temperature of the incoming gases rises to a pre-selected value.

2. An accumulator as defined in claim 1, and further characterized in that said inlet has a conduit portion extending exteriorly of the accumulator casing, said valve being located in said exterior portion.

3. An accumulator as defined in claim 1, and further characterized in that said inlet has a conduit portion extending interiorly of the accumulator casing, said valve being positioned in said interior portion.

References Cited UNITED STATES PATENTS 2,168,367 8/1939 Kucher 62-217 3,012,414 12/1961 La Porte 62503 MEYER PERLIN, Primary Examiner US. Cl. X.R. 62-503