US3032312A

US3032312A - Reversing valves

Info

Publication number: US3032312A
Application number: US759496A
Authority: US
Inventors: Frederick A Greenawalt
Original assignee: Ranco Inc
Current assignee: Robertshaw US Holding Corp
Priority date: 1958-09-08
Filing date: 1958-09-08
Publication date: 1962-05-01
Anticipated expiration: 1979-05-01

Description

y 1962 F. A. GREENAWALT 3,032,312

REVERSING VALVES Filed Sept. 8, 1958 2 Sheets-Sheet 1 IN VEN TOR: fimm/c/z /m /w/mz y 1952 F. A. GREENAWALT 3,032,312

REVERSING VALVES 2 Sheets-Sheet 2 Filed Sept. 8, 1958 United States Patent .0.

3,032,312 REVERSING VALVES Frederick A. Greenawalt, Fort Lauderdale, Fla., assignor to Ranco Incorporated, Columbus, Ohio, a corporation of Ohio Filed Sept. 8, 1958, Ser. No. 759,496 4 Claims. (Cl. 251356) The present invention relates to an improved fluid valve structure of the type comprising a chamber having a plurality of adjacent valve ports and a recessed slide valve member slidable over certain of the ports to open and close alternate fluid passages.

The principal object of the present invention is the provision of an improved slide valve member particularly suitable for use in a valve structure of the type mentioned and connected in a refrigerating system for selectively shifting the path of flow of refrigerant in the system, the improved valve member comprising a shell-like structure having a flexible, low friction seal surrounding the open edge and presenting a fluid-tight and relatively low friction slide surface engaging the port area of the valve chamber, the shell proper being formed of two separate shell-like elements having the rim sections thereof shaped to mechanically secure the seal to the shell and the inner concave surfaces of the elements being spaced apart intermediate the rim edges thereof to provide a heat exchange barrier.

Other objects and advantages of the invention will be apparent from the following description of a preferred embodiment of the same, reference being made to the accompanying drawings wherein FIG. 1 is a schematic view of the improved reversing valve shown partly in section and connected in a refrigerating system for reversing the order of flow of the refrigerant through the heat exchangers;

FIG. 2 is a sectional view taken on line 22 of FIG. 1 but on a larger scale;

FIG. 3 is a view taken along line 3--3 of FIG. 1 but on a larger scale;

FIG. 4 is an exploded view of a valve member of the improved valve; and

FIG. 5 is a sectional view taken on line 5-5 of FIG. 2.

The improved valve member may be used in any suitable type of sliding valvestructure, but is particularly suited for use in a slide type reversing valve in a refrigerating system of the compressor-condenser-expander type, as shown in the accompanying drawings, for providing either heating or cooling from one of the heat exchangers, as explained more fully hereinafter. Referring to FIG. 1 of the drawings, the refrigerating system, illustrated schematically, comprises an electric motordriven compressor 10, the discharge of which is connected by a tube 11 to a reversing valve 12, Which valve includes a cylindrical chamber 13 provided with three adjacent ports 14, 15, 16 which are disposed opposite the inlet with which tube 11 is connected. Port 14 is connected by tube 17 to the inlet of a heat exchanger 18, the outlet of which exchanger is connected by a suitable flow restricting device 19 to the inlet of a heat exchanger 20, the outlet of which exchanger is connected by tube 21 to port 15 of the valve. Port 16 is connected by tube 22 to the inlet of the compressor 10. Heat exchangers 18 and 20 each may serve either as a refrigerant condenser or a refrigerant evaporator, respectively, according to the order or direction of flow of refrigerant therethrough, which direction is controlled by valve 12. This refrigeration circuit is well known in the art and is frequently used to provide either heating or cooling of a room, for

3,032,312 Patented May 1, 1962 example, by circulating room air over the exchanger 20 and circulating outside air over exchanger 18, the exchanger 20 either cooling or heating the room air according to whether it is functioning as an evaporator or as a condenser.

Valve 12 and its general mode of operation is similar to that shown and described in my co-pending patent application Serial Number 705,893, filed December 30, 1957, and-now Patent No. 2,976,701, issued March 28, 1961, and as mentioned comprises cylinder 13 which has a port block 25 secured therein as by brazing,-which block has the three adjacent port openings 14, 15, 16 therethrough, the upper surface or face 26 of the block providing a smooth, flat sliding surface for a sliding valve member 27, which is the subject of the present invention.

Valve member 27 is of concave shell-like form having the edges of its open side engaging the face 26 of block 25 and is arranged to cover the center port 16 at all times but only one or the other of ports 14 or 15 according to its position on the block and thereby provide a refrigerant passage either from port 14 to port 16 or from port 15 to port 16. The fluid passage formed by member 27 is sealed from the interior of chamber 13 and when ports 14 and 16 are connected by valve member 27, port 15 is open to the interior of chamber 13 and when port 15 is connected by the valve member to port 16, port 14 is open to the interior of chamber 13, as may be seen in FIG. 1.

Valve member 27 is selectively shifted to reverse the port connections by a piston structure comprising a plate 30 having a central opening 30' through which valve member 27 projects so that the edges of the opening engage the valve member to shift and guide it in reverse sliding movements longitudinally on block 25, the plate having pistons 31, 32 attached at opposite ends for driving the plate, as described hereinafter. Each piston carries a valve structure 31, 32 respectively.

Cylinder 13 is closed at opposite ends by

caps

34, 35, each of which has a

valve port

36, 37, respectively which are closed by valve members 31' and 32 respectively, as pistons 31, 32 approach the respective ends of the cylinder. 'Port 36 is connected by a tube 38 to a port 39 of a three-way pilot valve 40, and port 37 is connected by a tube 41 to a port 42 of the pilot valve. A third port 43 of valve 40 is connected by a tube 44 to tube 22, leading to the suction side of the compressor. Valve 40 is described in my said co-pending application, and sufiice to say it includes a double valve closure member 45 actuated by a spring biased armature 46 of a solenoid 47 to open valve passages from ports 39 to port 43 and close the valve passage to port 42 when the solenoid is energized and when the solenoid is de-energized the valve passage from port 42 to port 43 is opened and the valve passage from port 39 to 43 is closed. Thus opposite ends of the cylinder 13 may be alternately connected to the suction side of the refrigerating system by energizing and dc-energizing solenoid 47. As described in the aforementioned co-pending application, pistons 31, 32 have bleed passages therethrough (not shown here) which permit high pressure refrigerant to pass through the pistons and enter the ends of the cylinder 13 beyond the pistons but the bleed openings are of substantially less capacity than the passages from the ends of the cylinder through valve 40 to the low side of the refrigerating system.

It will be seen that when solenoid 47 is energized, the right-hand end of cylinder 13 is connected to the low side of the refrigerating system and the interior of the cylinder has high pressure refrigerant entering through tube 11, therefore the pressure differential on opposite sides of piston 31 causes the piston to move to the righthand end of the cylinder and shift plate 30 and valve member 27 to the right and remove the valve member from over port 15 to cover port 14. The refrigerant passing through the bleed opening through piston 31 is vented from the endof the cylinder as fast as it enters until valve 31 shuts off the bleed passage 38 by engaging port 36. When solenoid 47 is tie-energized the left-hand end of cylinder 13 is connected to the low side of the refrigerating system causing piston 32, plate 30 and member 27 to be shifted by the pressure differential on opposite sides of the piston to the position shown in FIG. 1. i

As far as the present invention is concerned, any other suitable means could be employed to shift valve member 27.

Valve member 27 is comprised of an outer concave member 50, preferably formed of a sheet metal stamping, and a similarly formed inner concave member lnesting within member 50, the members being formed so that the trim portions thereof engage one another or are quite closely spaced, while the portions intermediate the rims are spaced an appreciable distance to provide a dead space between the walls to minimize heat transfer through the wall of the structure formed by the two members.

The rim of valve member 27 has a generally ovalshaped seal member 55 extending thereabout which is preferably formed of a plastic material having a low coeflicient of friction, such as tetrafluorethylene, and provides a sliding surface 58 lying'in a plane spaced outwardly from the open edges of

members

50, 51. Two

undercut surfaces

59, 60 are provided on opposite sides of surface 58,and the inner edge of member 51 is turned outwardly to form a flange 61 which firmly engages surface 59, and outer member 50 has an out-turned flange 62 formed thereabout which forms a backing for the seal 55. 'The

shell members

50, 51 are drawn into nested relation by a rivet 52 so that flange 61 tightly presses the inner edge of seal 55 t1 flange 62. Preferably, a solder seal is provided between the rivet and the adjacent edges of the opening in member 50 to prevent leakage.

The outer edge of seal 55 is tightly pressed to flange 62 by a metal band 64, the upper and lower edges of which are rolled inwardly onto flange 62 and surface 60 to tightly secure the seal to the under surface of the flange, thereby forming a gas-tight seal between the seal member and outer shell member 50.

To prevent inward deformation of the sides of valve member 27, a pin 53 having the end portions reduced in diameter is inserted in openings in opposite sides of the inner member 51 as may be seen in FIG. 2, thereby resisting inward pressure on the sides of the shell members. Preferably, a bleed opening 54 is provided in inner shell member 51 in communication with the space between the two

shell members

50, 51 to prevent possible accumulation of high pressure between the two members by leakage between the rims.

The surface 58 of seal 55 slides on the face of port block 25 and due to the differential in pressure between the high pressure refrigerant in cylinder 13 over valve member 27 and the low pressure refrigerant passing through the interior of the valve member, a load is placed on this member which causes seal 55 which is slightly flexible, to provide a substantially leak-proof sliding connection with the port block. Furthermore, the low friction character of the tetrafluorethylene seal provides a minimum of resistance to sliding of the valve on the block. The two

members

50, 51 being preferably formed of sheet metal provide a strong and gas-impervious structure for valve member 27, yet having a'minimum of heat exchange through the walls thereof between the relatively cool refrigerant passing through the inside of the valve member and the hot gas in the cylinder. Also, the valve member 27 will withstand the highest refrigerant temperatures without losing its physical characteristics.

It will be seen that by my improved valve construction, a relatively inexpensive valve member is provided having a high degree of strength and efficiency in that leakage and heat transfer between the high and low pressure refrigerant passing through the valve is at a minimum and the member may be moved by a relatively low power, although subjected to considerable pressure.

While but one form of the invention has been described, it will be apparent that other forms, modifications and adaptations may be made without departing from the invention which is defined in the following claims.

1. A slide valve structure comprising a pair of nested concave sheet metal members having the portions intermediate the edges thereof spaced from one another to provide a barrier to heat exchange therethrough and each having a'flang'e extending laterally about the open side thereof, said flanges lying in spaced planes and having portions opposite one another, an annular seal extending around said open sides of said nested members and projecting radially thereof and having a surface in a plane beyond the flanges of said nested members to provide a sealing surface, one edge portion of said seal being gripped between said flanges, and means securing said sheet metal members in nested relationship. 2. A slide valve member comprising a pair of nested concave sheet metal members spaced apart throughout a substantial area intermediate the edge portions about the open sides thereof to provide a heat barrier, each member having a flange extending laterally about the open side thereof, said flanges lying in spaced planes and having portions opposite one another, and an annular seal extending around the open sides of said members and projecting radially thereof, said seal having a surface in a plane extending beyond the flanges of said nested members to provide a sealing surface for engaging a surface in said plane beyond the flanges of said nested members, one edge portion of said seal being gripped between said flanges.

3. A slide valve structure comprising a pair of nested concave sheet metal members spaced apart throughout a substantial area intermediate the edge portions about the open sides thereof to provide a heat barrier, each member having the edge portions thereof turned outwardly to provide spaced, opposed flanges lying in parallel planes, the flanges of the outer nested member extending radiallyv beyond the flange of the inner nested member, and an annular seal member extending around the open side of said nested members and having a radially extending surface lying in a plane beyond said flanges to provide a sealing surface, the inner edge portion of said seal being gripped between said flanges and said seal extending radially along the flanges of said outer member whereby the last mentioned flange provides a backing for said'.

seal member substantially throughout the entire width thereof.

4. A slide valve structure comprising a pair of nested concave sheet metal members spaced apart throughout a substantial area intermediate the edge portions about the open sides thereof to provide a heat barrier, each member having the edge portions thereof turned outwardly to provide spaced, opposed flanges lying in parallel planes, an annular seal member extending around said edge portions and radially beyond the edge of the inner nested member and having a surface lying in a plane beyond said flanges to provide 'a sealing surface, the inner edge portion of said seal being gripped between said flanges, and said seal extending radially along the flange of said outer member whereby the last mentioned flange provides a backing for said seal member substan-. tially throughout the entire, width thereof, and an annular band surrounding the outer periphery of said open 5 edges of said sheet metal members and seal member, said band having opposite edges turned inwardly to engage the outer edge portion of said seal member and to overlie the out-turned flange of the outer of said sheet metal members to grip the outer peripheral edges of said seal 5 member.

6 References Cited in the file of this patent UNITED STATES PATENTS 1,252,494 Pratt Jan. 8, 1918 FOREIGN PATENTS 722,410 France Dec. 29, 1931