US2472149A - Thermostatic expansion valve - Google Patents

Description

June 7, 1949. E. J. DiLLMAN THERMOSTATIC EXPANSION VALVE Filed Feb. 18, 1946 INVEN TOR.

M ATTORNEY Patented June 7, 1949 THERMOSTATIC EXPANSION VALVE Earnest J. Dillman, Detroit, Mich., assignor to Detroit Lubricator Company, Detroit, Mich., a

corporation of Michigan Application February 18, 1946, Serial No. 648,462

8 Claims. (Cl. 23692) 1 This invention relates to new and useful improvements in thermostatic expansion valves for refrigerating apparatus and more particularly to the type of valve in which the valve member operating means is responsive to the temperature and pressure of the refrigerant medium adjacent the outlet from the evaporator.

It is one object of this invention to provide a valve construction in which the necessity for sealing means between the valve controlled liquid line passageway and the suction line passageway from the evaporator is eliminated thereby avoiding frictional and other opposing resistances to free operation of the valve member by its operating means.

The invention consists in the improved construction and combination of parts to be more fully described hereinafter and. the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings to be taken as a part of this specification, there are fully and clearly illustrated several preferred embodiments of the invention, in which drawings:

Figure 1 is a diagrammatic view of a refri erating system showing the invention incorporated in a suction line type expansion valve which is in longitudinal central section,

Fig. 2 is a view partly in elevation and partly in longitudinal central section of a suction line valve showing another means for eliminating the operating rod packing,

Fig. 3 is a detail view in section on the line 3-3 of Fig. 2, and

Fig. 4 is a view similar to Fig. 2, but showin still another valve construction.

Referring to the drawings by characters of reference, I designates a refrigerant compressor which may be driven and controlled by any suitable means and which discharges compressed refrigerant medium into a condenser 2 and receiver 3 from which liquid refrigerant medium is fed through the liquid line 4 to the inlet 5 of the suction line expansion valve 6. Leading from the expansion valve outlet passageway I there is a conduit 8 connected to the evaporator 9 from which the refrigerant medium suction line or conduit It] connects to the inlet fitting ll of the expansion valve suction line passageway or pressure chamber I2 which has its outlet or pressure conduit fitting l3 connected by the suction conduit it to the inlet of the compressor l.

The expansion valve casing has a cup-like member l5 which is closed by a resilient metal diaphragm it which forms the movable wall of the thermostatic power element ll having a cover l8 which is hermetically sealed to the diaphragm l6 and member 03, as at ill. The power element chamber 20 is charged through a thereafter sealed filling tube 2! with a temperature responsive voltatile liquid such as Freon, for example. The casing member l5 has diametrically opposite apertures through its pressure chamber side walls to receive the conduit fittings II and I3, and has through its bottom wall an opening 22 concentric with the diaphragm I6. Sealed in the opening 22 there is a tubular valve body member 23 which extends into the passageway or chamber 12 and terminates adjacent the diaphragm l6. Adjustably screw-threaded on the body portion 24 within the passageway l2 there is a spring abutment member 25 which supports a helical coil spring 2 3 opposing expansion of the power element chamber 23 and movement of the diaphragm l-6 upon temperature increase. The upper end of the spring 26 abuts a reinforcing plate 21 which fits against the diaphragm l6. The body member 23 projects externally of the casing 'member l5 and has a longitudinal passageway 23 therethrough which intersects the suction line passageway l2 and leads from the valve inlet 5 within the external body member portion 29. The passageway 28 has a valve seat member 33 with a valve port 3i therethrough concentric with the diaphragm It. On the inlet side of the port 3! and engageable with the seat member 30 to close the port there is a valve member 32 which is carried by a valveoperating rod 33 which extends longitudinally within the passageway 28 and into the'suction line passageway [2 where it is securedto the reinforcing plate 21. On the outlet side of the seat member 30 there is a partition 3% having a guideway therethrough in which the rod-33 has a free sliding fit. Also, within and adjacent the suction line end of the passageway 28 there is a partition member 35 having a guideway through which the rod 33 also has a free sliding fit. In the side Wall of the external body member portion 29 there is a cylindrical outlet recess 36 between the valve port 3| and the casing member l5. Through the bottom wall of the recess 36 there is an eduction passageway or outlet duct 31 which leads from the passageway 28 between the partition 34 and the guide or partition member 35. Concentric with the recess 36 and also opening through its bottom wall there is a discharge passageway or outlet port 38 which connects into the passageway 26 between the valve seat member 30 and the partition 34, that is, it leads from the valve outlet chamber 39. The eduction passageway 31 and the discharge passageway 38 have their longitudinal axes inclined or converging such as to meet within the outlet conduit 1 which is hermetically sealed in the recess 35. Within the outlet conduit I there is a hollow plug member 40 having a converging diverging bore 4| of Venturi form therethrough providing a throat. The plug member til terminates short of or is spaced from the bottom or end wall of the recess 36 so as to protion passageway 31 discharges. The annular chamber 42 is formed by a nozzle portion or extension 43 of the discharge passageway 38 which extends concentrically into the converging portion of the bore 4i and terminates in spaced relation to the bore wall.

The operation of the valve of Fig. 1 is as follows: When the valve member 32 is open for the feeding of refrigerant medium to the evaporator 9, the refrigerant medium which discharges from the discharge passageway 38 into the plug member bore 4| will create a reduction of pressure on the eduction passageway 31 so that the pressure in the passageway 28 on the suction line side of the partition 34 will be reduced below the pressure in the valve outlet chamber 39. Accordingly any refrigerant medium which passes through the guideway in the partition member 34 will be drawn through the eduction passageway 31 into the outlet conduit 1 and be fed to the evaporator. The injector action of the cooperating discharge passageway 38 and Venturi bore 4| will reduce the refrigerant medium pressure in the passageway 28 between the partition 34 and the guide member 35 to such an extent that it will be less than the pressure in the suction line passageway I2 with the result that some superheated refrigerant medium may be drawn from the suction line passageway into the passageway 28 through the guide rod clearance in the guide member 35. The valve rod or stem 33 is therefore freely movable to transmit without frictional opposition any movement of the diaphragm I6 to the valve member 32, all without change in the desired response of the power element H to suction line temperature such as would be caused by leakage of refrigerant medium from the passageway 28 into the suction line passageway i2. Regulation of the valve member 32 in accordance with changes of temperature and pressure of the refrigerant medium in the passageway [2 which cause movement of the diaphragm i6 is well understood by those skilled in the art of thermostatic expansion valves.

Referring to Figures 2 and 3, the valve is of the same general construction as that in Fig. 1, but difiers therefrom in the following respects: The valve is of the multiple outlet type and each outlet conduit is itself formed with a Venturi like converging diverging portion 5! adjacent its body member outlet recess 52. Each conduit portion 5i thus provides a throat which is alined coaxially with its valve chamber discharge outlet 53 which has an extension or nozzle.

Eduction passageways 54, 55 lead from the guide passageway 28 into the outlet conduits 50. Each eduction passageway 54, 55 has its longitudinal axis converging toward and intersecting the longitudinal axis of its respective discharge passageway, the point of intersection being in the outlet passageway adjacent the inlet to its respective converging bore portion. Refrigerant medium discharging through passageways 53, thus creates, in cooperation with the Venturi portions, a reduction of pressure in the eduction passageways and the passageway 28 between the partition 34 and the valve rod guide member 35. The operation of this construction will be apparent from the foregoing description of the operation of the valve of Fig. 1.

In Figure 4, the reduction of pressure in the passageway 28 between the partition 34 and the valve rod guide member 35 is obtained solely by the aspirating eflect of the refrigerant liquid discharging through the discharge passageways 60, I across the outlets of their respective eduction passageways i2, 63. In this construction of Fig. 4 both pairs of eduction and discharge passageways are inclined to the longitudinal axis of the passageway 28 and have their longitudinal axes converging at a point in the longitudinal center line of the respective outlet conduits 64, 65. The rest of the construction of this valve is the same as that of Fig. 1, the converging diverging portion of each of the outlet passageways being eliminated.

Having thus described my invention, what is claimed and is desired to be secured by Letters Patent of the United States is:

1. A thermostatic expansion valve, comprising a casing having a suction line passageway therethrough and having a second passageway intersecting said suction line passageway, said second passageway having an inlet and a valve port and having a partition therein with a guideway therethrough on the outlet side of said valve port, said casing having an outlet passageway with passageways leading thereto from said second passageway on the opposite sides of said partition, a valve member cooperable with said valve port, valve operating means responsive to changes of temperature and pressure in said suction line passageway, and a valve operating rod reciprocally fitting said guideway and said second passageway between said partition and said suction line passageway and operatively connecting said operating means and said valve member.

2. A thermostatic expansion valve, comprising a casing having a suction line passageway therethrough and having a second passageway intersecting said suction line passageway, said second passageway having an inlet and a valve port and having a partition therein with a guideway therethrough on the outlet side of said valve port, said casing having an outlet passageway with discharge and eduction passageways leading thereto from said second passageway, said discharge passageway leading from the valve port side of said partition, said eduction passageway leading from said second passageway between said partition and said suction line passageway, said discharge and eduction passageways having their longitudinal axes intersecting in said outlet passageway, a valve member cooperable with said valve port, valve operating means responsive to changes of temperature and pressure in said suction line passageway, and a valve operating rod reciprocally fitting said guideway and said second passageway between said partition and said suction line passageway and operatively connecting said operating means and said valve member.

3. A thermostatic expansion valve, comprising a casing having a suction line passageway therethrough and having a second passageway intersecting said suction line passageway, said second passageway having aninlet and a valve port and having a partition therein with a guideway therethrough on the outlet side of said valve port, said casing having an outlet passageway with discharge and eduction passageways leading thereto from said second passageway, said discharge passageway leading from the valve port side of said partition, said eduction passageway leading from said second passageway between said parti tion and said suction line passageway, said outlet passageway having a throat alined with said dis- 4. .A thermostatic expansion valve, comprising a casing having :a suction line passageway there- 'throush :and having :a second passageway intersecting :said suction jline passageway, said second passageway having an inlet and a valve port and having a partition therein with a ,guidewa therethrough on the outlet .side of said valve port, said casing having an outlet. passageway with disrcharge and eduction passageways leading thereto .from said second passageway, said discharge passageway leading from the valve port side of i :said partition, said eduction passageway leading from said second passageway between said partition .and said suction line passageway, :said discharge passageway extending into said outlet passageway beyond the extent of said eduction passageway, :a valve membercooperable with said valve port, valve operating means responsive to changes of temperature and pressure insaid suction liine passageway, and a valve operating :rod reciprocally fitting said guideway and said second passageway between said partition and said suction line passageway and operatively connecting said operating means and said valve member.

5. A thermostatic expansion valve, comprising .a casing having a suction line passageway theretintough and having a second passageway intersecting said suction line passageway, said second passageway .having an inlet and a valve port and having a partition therein with a guideway therethrough on the outlet side of said valve port, said casing having an outlet passageway with discharge and seduction passageways leading .thereto flrom saidsecond passageway, said discharge passageway leading .from the valve port side of said partition, said eduction passageway leading from .said second passageway between said partition and said suction line passageway, said outlet passageway having a converging-diverging portion ialined with said discharge passageway, said discharge passageway terminating concentrically within the converging portion, a valve member cooperable with said valve port, valve operating means responsive to changes of temperature and pressure in said suction line passageway, and a valve operating-rod reciprocally fitting said guideway and .said second passageway between aid partition and said suction line passageway and operatively connecting said operating means and .said valve member.

6. A thermostatic expansion valve, comprising a casing having a cup-like member forming a suction line chamber with inlet and outlet connections, a temperature responsiv power element having a pressure responsive diaphragm closing said cup-like member, a valve body member extending through the bottom wall of cuplike member concentric with said diaphragm and having :a passageway therethrough, a valve seat member in said passageway, a partition in said passageway and having a guideway therethrough concentric with said seat member, said partition being positioned external of said cup-like member and donning a wall of the valve outlet chama valve member cooperable with said seat member. an operating rod connectin said diaphragm to said valve member and having a 'free sliding fit :in said guideway, ,a :guide member in the suction line chamber end of said passageway and s'lidably receiving said rod, said body member 5 .having .a side wall recess .alined with said partition and having a passageway connecting said recess to said body member passageway between .said partition and said guide member, an outlet conduit sealed in said recess, a hollow :Dlllg fitting within said outlet conduit and extending into :said recess, said plug .havinga Venturi type bore, and -:a nozzle extension on said body member ,progieoting into said bore and having a discharge passageway therethroug'hleading fromsa'id valve :outletchamber.

An expansion valve, comprising a. casing i i-raving a pressure chamber with a pressure conduit and a passageway leading therefrom, a temperature responsive power element'havinga pressure movable wail forming a side of said pressure chamber, said passageway having an inlet and an outlet port and an outlet duct and having :a

valve port between saidinietand said outlet port, said passageway having spaced partition members with alined guideways therethrough and positioned at one side of said outlet port and on oppositesides of said outlet .duct, a valve member cooperable with said valve port, an operating rod reciprocally fitting said ,guideways and operativeiy connected to said movable wall and to said valve member, said casing having an outlet passageway into which said outlet port :andsa'id outlet duct discharge in intersecting streams in close proximity so that the discharge from said outlet port will create a reduction of' pressure in said outlet duct.

8. An expansion valve, comprising a casing having a pressure chamber "with a pressure conduit and a passageway leading therefrom, a temperature responsive power element having :a pressure movable wall forming a side of said pressure chamber, said passageway having an inlet and an outlet port and an outlet duct and having a valve port between said inlet and said outlet port, said passageway having spaced parti'tion members with alined guideways therethrough and positioned at one side of said outlet port and on opposite sides of said outlet duct, a valve member cooperable with said valve port, an operating rod reciprocally fitting said guideways and operatively connected to said movable wall and to said valve member, said casing having an outlet passageway into which said outlet port and said outlet duct discharge, said outlet passageway having a converging-diverging portion ,alined with said outlet port, said outlet port having "a nozzle extending into the outlet passageway converging portion, and said outlet duct discharging into said .outiet passageway converging portion at the side of said nozzle.

EARNEST J. DILLMAN.

REFERENCES CITED The following references are of .record .in the

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