US3242687A - Refrigeration system using polyphase expansion valve assembly - Google Patents

Description

March 29, 1966 w BAKER ETAL 3,242,687

REFRIGERATION SYSTEM USING POLYPHASE EXPANSION VALVE ASSEMBLY Filed Nov. 8, 1965 2 Sheets-Sheet 1 MPRESSO If mkl zuz fit ialaf 5 g 7 y 5 1 11-:

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REFRIGERATION SYSTEM USING POLYPHASE EXPANSION VALVE ASSEMBLY Filed NOV. 8, 1963 2 Sheets-Sheet 2 EVAPORATOR. w G :2: 2::

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ATTORNY United States Patent 3,242,687 REFRIGERATION SYSTEM USING POLYPHASE EXPANSION VALVE ASSEMBLY Marshall W. Baker, Lockport, and Paul K. Beatenhough,

Medina, N.Y., assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Nov. 8, 1963, Ser. No. 322,468 '7 Claims. (CL 62-214) This invention pertains to a refrigeration system and more particularly to a system especially adapted for air conditioning an automotive vehicle and a refrigeration throttling or expansion valve assembly in combination with altitude or ambient pressure compensation means for use in such a system.

Automotive air conditioning systems must contend with sharply varying and difficult conditions. They must have adequate cooling capacity to maintain comfortable incar temperature in city trafiic and at low road s eeds. Satisfying this requirement, they must be such as automatically to control the cooling capacity at intermediate and high road speeds while simultaneously protecting the system components insofar as the effects of variations in temperature and system pressure are concerned while retaining essential lubrication of the compressor. There are advantages in maintaining constant evaporator absolute pressure and these obtain particularly in automobile usage wherein changes in elevation are customary and usually frequent. The condensing and freezing of moisture from the atmosphere on the core of the evaporator must be prevented. Calibration of the system to suit personal preferences must also be possible and without undue complications and the system should be simple in construction and operation as well as low in cost.

An object of the present invention is to provide an improved refrigeration system in which the above-mentioned desired results are realized. Another object is to provide an improved refrigerant throttling or expansion valve assembly in combination with change in altitude or ambient pressure compensation means whereby a constant evaporator pressure may be attained.

A feature of the present invention is a refrigeration system using a high velocity refrigerant circuit through a compressor, evaporator and a condenser, the latter two components being connected by an altitude-compensated throttling or expansion valve assembly capable of handling not only all liquid refrigerant, but mixtures of vapor and liquid refrigerant, and possibly all vapor refrigerant. Another feature is an altitude-compensated expansion valve assembly capable of serving as a single control valve in a refrigerant circuit and combined with a pressureactuated device and spring arrangement by means of which a desired evaporator pressure may be automatically maintained under all operating conditions and conveniently adjusted. One other feature is a laminated valve structure, the necessary passages in the structure being formed in flat plates constituting the laminations the final assembly of which is brazed into an integral unit.

These and other important features of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims, a

In the drawings:

FIGURE 1 is a diagrammatic view of a refrigeration system in which the present invention is embodied;

FIGURE 2 is a sectional view of a polyphase expansion valve assembly employed in the system of FIG- URE 1;

FIGURE 3 is a sectional view drawn to a reduced scale and taken along the line 3-3 of FIGURE 2;

FIGURE 3a is a similar sectional view but taken along y the line 3a3a of FIGURE 2;

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FIGURE 4 is taken along the line 4-4 of FIGURE 2;

FIGURE 5 is taken along the line 55 of FIGURE 2;

FIGURE 6 is taken along the line 6-6 of FIGURE 2;

FIGURE 7 is taken along the line 77 of FIGURE 2; and

FIGURE 8 is a diagrammatic view of a portion of the system of FIGURE 1 as modified.

In FIGURE 1 the system is shown as comprising a three-pass evaporator 10, a compressor 12, a condenser 14, and a special expansion valve 16. A line 18 connects the evaporator 10 to the intake of the compressor and line 20 connects the discharge side of the compressor to the condenser 14. The latter is connected by a line 22 to an inlet nipple 24 of the valve 16. An outlet nipple 28 of the latter is connected by means of a line 30 to the evaporator 10. The compressor 12 is preferably of a type having a high tolerance for a high percentage of refrigerant liquid entrainment in the vapor (mixture) being compressed. There are many ways heretofore used in refrigeration systems for achieving an elevated degree of tolerance for liquid refrigerant in compressors. An example of a suitable compressor is disclosed in the United States Patent No. 3,057,545, granted April 11, 1960, in the names of G, P. Ransom, W. K. Steinhagen and D. C. Unger.

The main body of the valve 16 comprises two end plates 32 and 34 between which are retained discharge port plate 36, 38, three valve guide plates 40, one inlet port plate 42, one outlet port plate 44, two rod guide plates 46, one equalizer plate 48 and one diaphragm chamber plate 50. These plates are all held at least initially together by bolts 52 to insure proper and fluid tight bonding in brazing the plates together. The plates making up the valve may conveniently be made of aluminum, steel or copper.

The end plate 32 is apertured as at 54 tightly to receive the outlet nipple 28. The end plate 34 and its adjacent plate 50 are apertured as at 56 tightly to receive the inlet nipple 24. The plate 36 (FIGURE 3) has two relatively large apertures 58 and 60 and a smaller aperture 62. It also bears six holes 64 for receiving the bolts 52. The apertures 60 and 62 communicate by means of a slot 66. Each of the two plates 38 is similar to plate 36 except that the aperture 60 and 62 do not communicate (FIG- URE 3a). The three valve guide plates 40 are each as depicted in FIGURE 4 and are made to accommodate the bolts 52. Each plate 40 bears a large aperture 70 conforming with the aperture 58. Each plate 40 also is provided with four holes 72, a hole 74 conforming with the aperture 62 of the plate 36 and also a hole 76 placed between the hole 74 and the large opening 70.

The inlet port plate 42 is made to accommodate the 'bolts 52 and also bears a large aperture 80 which conforms with the apertures 58 and 70 except that it extends downwardly in the form of a slot 82. This slot terminates in a zone located in the area between four holes 86 and the latter are made to register with the holes 72 in the assembly. The plate 42 also has a hole 88 adapted to register with the holes 62 and 74.

Each of the rod guide plates 46 is depicted as shown in FIGURE 6 and is provided wtih a large aperture 90 and a smaller hole 92, these being adapted to register with the large aperture 70 and the small hole 74 respectively. Each plate 46 also includes six holes 94 for receiving bolts such as the bolt 96 (FIGURE 2). These holes 94 are not threaded until after assembly and brazing of the valve. Between the large opening 90 and the small open ing 92 is a central opening 98.

The equalizer plate 48 has a large aperture 100, siX holes 162 surrounding a relatively large opening 104 and connected with the latter by means of a slot 106 is a small opening 108.

With the plates joined together as shown in FIGURE 2 they form a laminated valve body and the apertures in the plates are in registry to form an inlet chamber at 110, an inlet or supply port at 82, and two valve bores at 114 and 116 formed by the aligned holes 76. In the assembly, one of the two plates 38 defines a fiat chamber 118. There are four passages 120 for the free flow of refrig erant from the chamber 118 to a chamber 121 connected with the outlet nipple 28. The plates also form an extra and lowest chamber 126 which communicates with the chamber 121 by means of the slot 66 and with a chamber at one side of a diaphragm 123 by means of the slot 106.

A cylindrical valve member 122 is slidably retained and closely fitted within the valve bore 114 and retained on a reduced diameter portion 124 of a rod 127. The latter extends through the hole 76 of each of the plates 48 and is slidable and also is attached by a ball and socket joint arrangement 130 to the central portion of the diaphragm 123. The valve member 122 serves as a seal member between refrigerant at high pressure in the passage 82 and refrigerant at a lower pressure in chamber 121. A cup member 132 is fixed to the end plate 34 by means of the screws 96 and with the margin of the diphragm 123 interposed. The central portion of the bottom of the cup 132 is apertured as at 134 and formed with a recess 136. This recess is made with a diameter to coincide with that of the aperture 104 in the plate 48. A small cup 149 is retained to bear on the ball and socket arrangement 130 and is slidable within the aperture 134. Retained within the cup 132 is an inner cup 142 having fingers such as at 144 for retaining the cup 142 in axial alignment with respect to the cup 132. The lip of the cup 132 bears an annular flange 146 which is adapted to restrain a washer 148 and abutting the latter is an internally threaded knurled ring 150. This ring is in threaded engagement with a movable cup 152 which is adapted to move toward and away from the cup 132 and on the axis of the latter.

A hollow shaft 154 is fixed to the cup 152 and extends axially therein and is fixed to a disk 156 which serves as the sealed cover of a bellows indicated at 158. The other end of the bellows is fastened to the closed end of the inner cup 142. The bellows 158 may be evacuated by using the hollow shaft 154 sealed as at 160. A coil spring 162 is retained within the cups 152 and 142 and its surrounds the bellows 158. Ribs 153 on the cup 152 serve as centering guides for the spring 162.

In operation of the system, liquid refrigerant such as Freon and some entrained lubricating oil for the compressor 12 leaves the condenser 14 through the line 22 and passes through the valve 16 to the evaporator 10. The valve 16 so operates that a constant pressure will be maintained in the evaporator inlet despite changes in ambient temperatures, speed of the compressor or in ambient pressure. As the Freon evaporates in the evaporator it attracts heat from the air which is forced through the conventional core of the evaporator and refrigerant discharged from the evaporator passes through the line 18 to the compressor. The single valve 16 permits system operation without a reserved supply of refrigerant in the line. The flow, whether it be in a liquid or vapor state, or a mixture of liquid or vapor, is at a constant rate through the line 18 and is sufficient at all times to fulfill the demands of the compressor while maintaining the refrigerant pressure at the valve outlet within predetermined limits.

In operation of the valve 16 the refrigerant, whether it be all liquid, or all vapor, will pass through the chamber 110 and to the valve bore 116 by Way of the supply port 82. This refrigerant will then flow into flat chamber 118 and by way of the four passages 120 in the chamber 121. From this zone, the refrigerant passes through the nipple 28 to the evaporator. The chamber 121 is also in communication with the chamber at one side of the diaphragm 123 because of the chamber 126 and the passage 4 slot 106. The opening 134 in the base of the cup 132 is of such size that atmospheric air may enter around the knurled nut and engage one side of the diaphragm 123. The diaphragm 123, the bellows 158 and the spring 162 are so designed as to cooperate to control the valve member 122 whereby a desired pressure is maintained in the valve outlet 28. The valve member 122 is subjected to outlet pressure at both ends because throttling action takes place between the valve ,member and one of the plates 40. It is, therefore, a balanced valve member. The diaphragm 123 is acted upon by valve outlet pressure at one side and by atmospheric pressure on the other. The areas of the bellows and diaphragm exposed to the atmosphere are made equivalent. Expansion of the vacuumized bellows 158 is resisted by atmospheric pressure and the design is such that when atmospheric pressure reduces as when the system is operated at a high elevation the bellows 158 is relieved and thereby expands to permit the spring 162 to tend to move the diaphragm 123 and the valve member 122 to the left to positions as viewed in FIGURE 2. In other Words, the bellows 158 opposes expansion of the spring 162 at sea level but its opposition decreases as the elevation increases. The valve 116 maintains refrigerant flow at constant refrigerant pressure at the evaporator inlet at all times during normal operation when the compressor capacity equals or exceeds the capacity of the evaporator 10. The valve also provides additional flow of refrigerant liquid, liquidvapor mixture, or vapor (hence polyphase) to satisfy extra compressor capacity. When the compressor capacity is less than the evaporator capacity, calibrated leakage in the valve provides sufiicient refrigerant flow to allow the evaporator pressure to maintain nearly optimum cooling effect with the reduced compressor capacity. It will be noted that an oil bleed line around the evaporator is rendered unnecessary for the valve 16 permits high veloc ity refrigerant fiow in the evaporator and a good oil return to the compressor is assured. It will also be noted that a dehydrator is not essential.

With the present arrangement, however, the valve 16 operates well above the freeze point and cannot freeze and the moisture level is kept so low in the present system that there is little evidence of refrigerant decomposition or corrosion of the parts. The receiver or desiccant holder as customarily used in previous systems served as a container for reserve refrigerant but the tolerance of the present valve 16 in combination with the other components of the system for operating with refrigerant in the vapor as well as the liquid state, give satisfactory system performance and reliability without a receiver i.e.line 20 includes no receiver so that line is characterized by having a constant velocity flow along its length. A temporarily installed service dehydrator can be used to dry out systems involving the present invention if the admission of moisture is encountered inadvertently or otherwise. Further processing of the system by flushing and evacuation should be easier and more effective with equal or better results when compared to a system using a dehydrator.

Heretofore, an external pressure sensing line has been used to override the expansion valve into opening under low compressor inlet pressure so as to flood liquid refrigerant through the evaporator into the compressor suction line. This has been necessary to prevent too low a pressure at the compressor inlet when the compressor capacity exceeds evaporator load. Such an external equalizer line is not necessary in the present system since the valve 16 maintains the evaporator inlet pressure at a predetermined amount,

It has been customary heretofore to use a sight glass in refrigeration systems to detect the presence of gas in the liquid line as an aid in diagnosing system malfunctions. Since gassing is expected under many operative conditions, the sight glass has been omitted from the present system.

It will be appreciated that if an evaporator pressure higher than anticipated is desired, the loading of the spring 162 may be changed by rotating the knurled nut 150. The system results in a constant evaporator pressure determined by the adjustment of the nut 150 but the specific type of control of air temperature in the passenger compartment of a car in which the present system is installed is not involved. This control may be effected by various expedients such as reheatingi.e.-heating the air after cooling and drying it. The valve 16 is characterized by high sensitivity to give a constant outlet pressure under normal conditions. This outlet pressure is departed from only under conditions where the compressor is of low capacity with a high heat input to the evaporator. The valve member 122, being balanced, adds to the sensitivity.

The above description pertains to a valve and system using an internal equalizing connectioni.e.--a system in which the valve outlet is closely coupled to the evaporator inlet. If the evaporator outlet pressure becomes more critical or more important than the evaporator inlet pressure under given conditions in the control of refrigerant, then the slot 66 could be closed off and an exterior equalizing connection such as the line 200 and the fitting 202 of FIGURE 8 could be added. With this arrangement, the valve 16 may be said to be externally equalized as it responds to pressures at a location external to the valve. It is obvious that several places on the evaporator could serve as a suitable location for connection to the equalizer line leading to the valve side of the diaphragm 123.

From the above description, it will be noted that the system is characterized by at least four important aspects: (1) the high rate of refrigerant flow through the special valve 16 to the multipass evaporator is accompanied by a gradual reduction of refrigerant pressure and not a sudden reduction. This combination of the multi-pass evaporator and a control valve in the system therefore permits elimination of an excess refrigerant receiver and promotes over-all simplicity and reduces cost; (2) the system operates independent of barometric pressure changes by virtue of the special valve construction; (3) the valve 16 operates well above the freeze point of residual moisture in the system and cannot freeze; and (4) no suction throttling valve is needed in the line 18.

We claim:

1. A refrigeration system including an evaporator, a compressor, a condenser and a polyphase expansion valve assembly comiected in that order in a closed circuit, said valve assembly having a body with a supply port connected to said condenser and an outlet port connected to said evaporator, two aligned valve bores in said body each connecting said ports, a valve member slidable in one of said bores, a rod fixed to said valve member and slidable in said body, a diaphragm fixed to said rod with one side exposed to pressure in said outlet port and the other side to ambient pressure, and resilient means including a spring and bellows arrangement mounted to act on said diaphragm to compensate for ambient pressure fluctuation.

2. A refrigeration system such as set forth in claim 1, said resilient means being adjustable to vary the evaporator pressure.

3. A refrigeration system as set forth in claim 1, said resilient means including a cup arangement enclosing said bellows and spring and said valve assembly having a laminated body.

4. A refrigeration system as set forth in claim 1, one end of said bellows and one end of said spring being fixed in position with relation to said valve assembly body, and the other ends of said bellows and spring being movable with said valve.

5. A refrigeration system as set forth in claim 4, and said fixed ends. of said bellows and spring being adjustable in their positions with relation to said valve assembly body.

6. A polyphase expansion valve assembly having a body with a supply port and an outlet port, two aligned valve bores in said body, an open passage leading from said supply port and terminating at said bores, a valve member slidable in one of said bores, a rod having one end fixed to said valve member and an intermediate portion extending through the other of said bores, another portion of said nod being journaled in said body, a diaphragm fixed to the other end of said rod with one side exposed to pressure in said outlet port and the other side to ambient pressure, and resilient means including a spring and bellows arrangement mounted to act on said diaphragm to compensate for ambient pressure fluctuation.

7. A polyphase expansion valve assembly such as set forth in claim 6, a bellows of said spring and bellows arrangement being vacuumized and a spring of the latter cooperating with said bellows in affecting the position of said valve member with respect to said other valve bore.

References Cited by the Examiner UNITED STATES PATENTS 2,463,892 3/ 1949 Martin 62224 X 2,947,320 8/ 1960 Oxley l3727'l 3,180,107 4/1965 Baker 62-209 MEYER PERLIN, Primary Examiner.

Claims (1)

1. A REFRIGERATION SYSTEM INCLUDING AN EVAPORATOR, A COMPRESSOR, A CONDENSER AND A POLYPHASE EXPANSION VALVE ASSEMBLY CONNECTED IN THAT ORDER IN A CLOSED CIRCUIT, SAID VALVE ASSEMBLY HAVING A BODY WITH A SUPPLY PORT CONNECTED TO SAID CONDENSER AND AN OUTLET PORT CONNECTED TO SAID EVAPORATOR, TWO ALIGNED VALVE BORES IN SAID BODY EACH CONNECTING SAID PORTS, A VALVE MEMBER SLIDABLE IN ONE OF SAID BORES, A ROD FIXED TO SAID VALVE MEMBER AND SLIDABLE IN SAID BODY, A DIAPHRAGM FIXED TO SAID ROD WITH ONE SIDE EXPOSED TO PRESSURE IN SAID OUTLET PORT AND THE OTHER SIDE TO AMBIENT PRESSURE, AND RESILIENT MEANS INCLUDING A SPRING AND BELLOWS ARRANGEMENT MOUNTED TO ACT ON SAID DIAPHRAGM TO COMPENSATE FOR AMBIENT PRESSURE FLUCTUATION.

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