GB2168789A

GB2168789A - Poppet valve

Info

Publication number: GB2168789A
Application number: GB08528424A
Authority: GB
Inventors: Donald Jerome West
Original assignee: Ross Operating Valve Co
Current assignee: Ross Operating Valve Co
Priority date: 1984-12-24
Filing date: 1985-11-19
Publication date: 1986-06-25
Also published as: FR2575263B1; ZA859722B; GB8528424D0; DE8533506U1; DE3542062C2; ZA876751B; CN85109004A; ES550325A0; SE8506038L; IT1200872B; JPH0756349B2; FR2575263A1; CA1264266A; DE3542062A1; DD245704A5; GB2168789B; SE8506038D0; BR8506460A; JPS61157880A; IT8523182A0

Abstract

A poppet valve assembly comprises a poppet valve member 212 with sealing surfaces 266, 268 which define different effective sealing areas. Preferably two poppet valve elements 212, 214 are mounted on a single shaft 240 for simultaneous operation relative to fixed and movable valve seats 204, 206; and 208, 210 respectively. <IMAGE>

Description

SPECIFICATION Improved inline poppet valve Background and summary of the invention The present invention relates generally to valve assemblies and more particularly to multi-position, multi-way valve assemblies utilising a plurality of poppet type valve members mounted on a single actuating shaft.

Heretofore it has been extremely difficult and costly to utilise poppet type valve members in multi-position, multi-way valve assemblies. One of the primary reasons for this difficulty resides in the fact that such valves typically provide a plurality of valve members or elements operated by a single actuating shaft. Because in poppet valves the valve member moves generally perpendicularly to the valve seat, it is necessary to position the respective valve seats within the valve assembly so as to assure a substantially simultaneous secure fluid-tight sealing engagement of all of the valve members therewith. This has required that exceedingly tight tolerances be adhered to which is not only very difficult in volume production but also is very costly.It is also very desirable with such multi-position, multi-way valves to design the valve so that it is stable or self-sustaining in the various positions thus eliminating the need to apply a continuous actuating force to maintain it in position.

The present invention provides a net pressure created force which is operable to maintain the valve assembly in either of its two positions. This is accomplished by selectively controlling the relative surface areas against which the pressurised fluid being controlled by the valve acts so as to thereby create a net pressure imbalance acting in a direction to hold the valve in the desired position.

Thus in the present invention, the only actuating force required is that necessary to shift the valve assembly from one position to the other and no external sustaining force is required to maintain it in that position.

In accordance with one feature of the present invention, the relative surface areas against which the pressurised fluid acts is controlled at least in part by a non-symmetrical poppet valve member construction. Specifically, the poppet valve member is provided with first and second sealing surfaces which each define different predetermined surface areas against which the pressurised fluid in the bore of the housing will apply an axially directed force. In one embodiment according to the present invention, these sealing surfaces each comprise a continuous annular rib of elastomeric material. These annular ribs are disposed on opposite sides of the poppet valve member, and the diameter of one of the annular ribs is greater than the diameter of the other annular rib.

Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.

Brief description of the drawings Figure 1 is a section view of an embodiment of a two position, four way valve assembly in accordance with the present invention.

Figure 2 is an enlarged section view of one of the poppet valve members shown in Figure 1.

Figure 3 is a plan view of the poppet valve member shown in Figure 2.

Figures 4 and 5 are two plan views of the washer-shaped core of the poppet valve member shown in Figure 2.

Figure 6 is an enlarged section view of one of the fixed valve seats shown in Figure 1.

Figure 7 is an enlarged section view of one of the movable valve seats shown in Figure 1.

Figure 8 is a plan view of the movable valve seat shown in Figure 7.

Description of the preferred embodiment Referring now to the drawings, a valve assembly 200 is a two position four way valve. However, it will be appreciated from the description below that the principles of the present invention may also be used with other types of valves, such as a two position two way valve, for example forming the subject of our GB-A-2154707. The valve assembly 200 generally comprises a housing 202, a first fixed valve seat member 204, a second fixed valve seat member 206, a first movable valve seat member 208, a second movable valve seat member 210, a first poppet valve member 212, a second poppet valve member 214, and an actuator 216.

The housing 202 is provided with a bore 218, which is generally designated by the reference numeral 218. As shown in Figure 1, the diameter of the bore 218 is suitably contoured to conform to the shape of the valve seat members, as well as to provide appropriate paths for fluid flow. The housing 202 is also formed with an inlet opening or port 220, a first outlet port 222, a second outlet port 224, a first exhaust port 226, and a second exhaust port 228.

Three chambers are also provided within the housing 202. The first chamber 230 is generally disposed between the poppet valve members 212 and 214. The second chamber 232 is generally disposed between the poppet valve 212 and a piston generally designated by the reference numeral 234.

The third chamber 236 is generally disposed between the poppet valve 214 and a piston generally designated by the reference numeral 238.

The actuator 216 includes a central shaft or rod 240 upon which the poppet valve members 212 and 214 are mounted. The actuator 216 also includes a spool 242 which separates the poppet valve members 212 and 214. Accordingly, the poppet valve member 212 is interposed between the spool 242 and the piston 234, and the poppet valve member 214 is interposed between the spool 242 and the piston 238. The combination and shapes of the spool 242 and the pistons 234 and 238 also assist in keeping the poppet valve members 212 and 214 in a position generally perpendicular to the shaft 240.

The actuator 216 also includes a pair of spacers 244 and 246 which support the cup-shaped seal members 248 and 250. Locknuts 252 and 254 are secured generally at the ends of the shaft 240 to retain the above described components in position on the shaft 240. As will be appreciated by those skilled in the art, one or both ofthe ends of the shaft 240 may be connected to a solenoid valve to control the articulation of the actuator 216 in an actual direction. Alternatively, one or more of the housing ends 256 and 258 may be formed to provide a conduit through which fluid pressure may be applied to cause an axial articulation of the actuator 216.As also shown in Figure 1, it may be desirable in certain circumstances to provide a piston construction in which one of the pistons is smaller than the other. in this situation, a cylindrical sleeve 260 is interposed between the smaller (return) piston 238 and the fixed valve seat member 206.

Turning now to a description of the poppet valve members 212 and 214, it should first be noted that these poppet valve members are of identical construction. Accordingly, only one of these poppet valve members will be described in detail. An enlarged sectional view of the poppet valve member 212 is shown in Figure 2. A plan view of the poppet valve member 212 is also shown in Figure 3.

The poppet valve member 212 generally comprises a washer-shaped metal core 262 and an elastomeric sheath 264 which generally surrounds the core 262. Figures 4 and 5 show two plan views of the metal core 262. The sheath 264 is formed with a first sealing surface 266 and a second sealing surface 268. Each of these sealing surfaces 266-268 comprises a continuous annular rib having a generally semi-circular cross section. As best seen in Figure 2, the sealing surfaces 266-268 are disposed on opposite sides of the poppet valve member 212.

Additionally, it is important to note that the diameter "K" of the sealing surface 266 is greater than the diameter "L" of the sealing surface 268. As will be seen from the description below this non-symmetrical construction of the sealing surfaces 266268 provides a desirable pressure imbalance within the valve assembly 200. It should be appreciated that the particular poppet valve construction shown in Figure 2 is not intended to limit the present invention, and that other non-symmetrical sealing surface constructions providing the aforementioned pressure imbalance may be employed in the appropriate application.

Referring both to Figures 1 and 6, it will be seen that the fixed valve seat members 204 and 206 have a generally cylindrical shape. As in the case of the poppet valve members, the fixed valve seat members 204 and 206 are identical, and therefore only the fixed valve seat member 206 will be described. The second fixed valve seat member 206 is formed to provide a generally radially extending valve seat surface 270. The valve seat surface 270 will be closed by the first sealing surface 266' of the poppet valve member 214. The fixed valve seat member 206 is also provided with a plurality of openings 272 to permit fluid communication between the second outlet port 224 and the second exhaust port 228 when the valve seat 270 is open.

The fixed valve seat member 206 is also formed with an axially extending surface 274 which engages the coaxially disposed sleeve 269. It should be noted that this surface will be engaged by the cup-shaped seal member 248 in connection with the first fixed valve seat member 204. Suitable annular elastomeric seal rings 276 and 278 are also included to provide a fluid-tight seal between the housing 204 and the fixed valve seat member 206.

Additionally, it should be noted that the fixed valve seat member 206 is formed with a plurality of circumferentially spaced axially extending cavities 280 at one end thereof.

Referring now to Figures 1, 7 and 8, the movable valve seat members 208 and 210 willow be described. Here again, since the movable valve seat members are identical in construction, only the valve seat member 210 will be described. The movable valve seat member 210 includes a cylindrical portion 282 which is formed with an outwardly facing annular groove 284. An annular sealing ring 286 is disposed in the groove 284 to provide a fluid-tight seal between the movable valve seat member 210 and the housing 202. It should be noted that the exterior surface 286 of the movable valve seat member 210 is sized relative to the bore 218 of the housing 204 to permit the valve seat member to slide axially with respect to the housing.The movable valve seat member 210 also includes an annular flange portion 288 which extends outwardly in a radially direction from one end of the -cylindrical portion 282. The flange portion 288 provides a valve seat surface 289 which can be closed by the second sealing surface 268' of the poppet valve member 214. The flange portion 288 is formed with a plurality df circumferentially spaced outwardly opening cavities 290. The flange portion 288 of the movable valve seat member 210 acts as a stop to limit the axial movement of the valve seat member. In one direction the flange portion 288 will abut the housing 202, while in the other direction the flange portion will abut the fixed valve seat member 206.It should be noted that when the flange portion 288 of the movable seat member 210 engages the fixed valve seat member 206, the cavities 280 of the fixed valve seat member and the cavities 290 of the movable valve seat member combine to permit fluid com- munication between the chamber 236 and the space between the housing 202 and the flange portion 288, and to permit fluid communication between the chamber 236 and the second outlet port 224.

The operation of the valve assembly 200 will now be described. In the position of the actuator 216 shown in Figure 1, the first sealing surface 266 of the poppet valve member 212 will close the valve seat surface of the first fixed valve seat member 204, while the second sealing surface 268' of the poppet valve member 214 will close the valve seat surface 289 of the second movable valve seat member 210. As will be evident from the discussions of the previous embbdiments, the valve seat surface of the movable valve seat member to the right as shown by the phantom lines, the seat surface of the fixed valve seat member 204.

This feature is due in part to the dimensions of the fixed valve seat members 204 and 206 which cause a smaller distance "M" between the poppet valve members 212-214 and the movable valve seat members 208-210 than the distance "N" between the poppet valve members and the fixed valve seat members.

When the valve seat surface of the first fixed valve seat member 204 is closed, fluid communication is permitted between the inlet port 220 and the first outlet port 222 through the cavities 280 and 290. Fluid communication will also be prevented between the first outlet port 222 and the first exhaust port 226. The closure of the valve seat surface 289 of the second movable valve seat member 210 will permit fluid communication between the second outlet port 224 and the second exhaust port 228. Fluid communication will also be prevented between the inlet port 220 and the second outlet port 224.

When the actuator 216 is articulated to the right, it should first be noted that the second movable valve seat 210 will be drawn along with the poppet valve member 214 until the flange portion 288 en gages the second fixed valve seat member 206.

The second poppet valve member 214 will continue to move to the right until its sealing surface 266' closes the valve seating surface 270 of the second fixed valve seat member 206. Again, at or prior to the closing of this valve seat surface, the second sealing surface 268 of the poppet valve member 212 will close the valve seating surface of the first movable valve seat member 208. The clo sure of the valve seating surface of the first mova ble valve seat member 208 will permit fluid communication between the first outlet port 222 and the first exhaust port 226. Fluid communication will also be prevented between the inlet port 220 and the first outlet port 222. The closure of the valve seating surface 270 will permit fluid commu nication between the inlet port 220 and the second outlet port 224.Fluid communication will also be prevented between the second outlet port 224 and the second exhaust port 228.

It will be appreciated from the foregoing descrip tion that the first and second sealing surfaces 266 268 of the poppet valve members 212-214 each de fine a predetermined surface area against which a pressurised fluid in the first chamber 230 of the housing 202 will apply an axially directed force.

Since the diameter "K" of the first sealing surface 266 is greater than the diameter "L" of the second sealing surface 268, the predetermined surface area defined by the first sealing surface will be greater than that defined by the second sealing surface. Thus, with the valve assembly 200 in the position shown in Figure 3, the fluid pressure within the first chamber 230 will exert a greater force on the poppet valve member 212 than on the poppet valve member 214. Hence, there will be a net force acting in a left axial direction to maintain the poppet valve member 212 in the position shown. Similarly, when the actuator 216 is shifted 210 will close at or before the closing of the valve pressure exerted on the poppet valve member 214 will be greater than that exerted on the poppet valve member 212.Thus, the resulting pressure imbalance will maintain the valve assembly 200 stable in either of the two positions without the need for the application of an ongoing external force.

It should also be noted that the principles of the present invention embodied in the valve assembly 200 may be employed in other types of valve assemblies having more than two poppet valve members or even one poppet valve member. Thus, a poppet valve assembly according to the present invention may include only a single poppet valve member, a single fixed valve seat member and a single movable valve seat member. It should also be appreciated that some of the principles of construction employed in the previous two embodiments may be employed in a valve assembly of the type shown in Figure 1.

Thus, there is provided by the present invention a valve assembly which employs a plurality of poppet valves mounted on a single actuating shaft and designed to seat on a combination of fixed and movable valve seats whereby manufacturing tolerances may be easily accommodated.

While it will be apparent that the preferred embodiments of the invention disclosed are well calculated to provide the advantages and features above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

Claims

1. An improved inline poppet valve assembly, comprising: a housing having a first valve seating surface and a second valve seating surface provided therein; a poppet valve member secured to an actuator within said housing, said poppet valve member having first and second sealing surfaces, said first sealing surface being formed to close said first valve seating surface in response to the articulation of said actuator in one direction, and said second sealing surface being formed to close said second valve seating surface in response to the articulation of said actuator in the opposite direction, said first and second sealing surfaces each defining a predetermined surface area against which a pressurised fluid in said housing will apply an axially directed force, the predetermined surface area defined by one of said sealing surfaces being greater than the other of said sealing surfaces.

2. A poppet valve assembly as set forth in Claim 1 wherein the predetermined surface area defined by said first sealing surface is greater than the predetermined surface area defined by said second sealing surface.

3. A poppet valve assembly as set forth in Claim 1 wherein said first and second sealing surfaces are disposed on opposite sides of said pop pet valve member.

4. A poppet valve assembly as set forth in Claim 1 wherein said first and second sealing surfaces each generally comprise a continuous annular rib of elastomeric material.

5. A poppet valve assembly as set forth in Claim 4 wherein the diameter of one of said annular ribs is greater than the other of said annular ribs.

6. A poppet valve assembly as set forth in Claim 5 wherein both of said annular ribs have a generally semi-circular cross-section.

7. A poppet valve assembly as set forth in Claim 1 wherein said poppet valve member comprises a metallic washer-shaped core and an elastomeric sheath covering at least both sides of said core, said sheath being formed with a continuous annular rib on opposite sides of said core, the diameter of one of said annular ribs being greater than the other of said annular ribs.

8. A poppet valve assembly as set forth in Claim 7 wherein said sheath generally surrounds said core.

9. A poppet valve assembly as set forth in Claim 1 wherein said actuator includes a shaft and a pair of spools concentrically disposed on said shaft, said poppet valve member being interposed between said spools.

10. An improved inline poppet valve assembly, comprising: a housing; a fixed valve seat and a movable valve seat provided in said housing; a poppet valve member secured to an actuator within said housing, said poppet valve member having first and second sealing surfaces, said first sealing surface being formed to close said fixed valve seat in response to the articulation of said actuator in one direction, and said second sealing surface being formed to close said movable valve seat in response to the articulation of said actuator in the opposite direction, said first and second sealing surfaces each defining a predetermined surface area against which a pressurised fluid in said housing will apply an axially directed force, the predetermined surface area defined by one of said sealing surfaces being greater than the other of said sealing surfaces.

11. A poppet valve assembly as set forth in Claim 10 wherein said movable valve seat is axially movable within said housing in response to the articulation of said actuator.

12. A poppet valve assembly as set forth in Claim 11 wherein said movable valve seat includes a cylindrical portion formed with an outwardly facing annular groove, an annular sealing element disposed in said groove for providing a seal between said movable valve seat and said housing, and an annular flange portion extending outwardly in generally radial direction from one end of said cylindrical portion, said flange portion being formed with a plurality of circumferentially spaced outwardly opening cavities.

13. A poppet valve assembly as set forth in Claim 12 wherein said flange portion of said movable valve seat cooperates with one end of said first valve seat to limit axial movement of said movable valve seat in one direction.

14. A poppet valve assembly as set forth in Claim 13 wherein said one end of said fixed valve seat is formed with a plurality of circumferentially spaced axially extending cavities.

15. A poppet valve assembly as set forth in claim 10 wherein said housing includes first, second and third ports which are disposed in said housing relative to saidpoppet valve member such that: the closure of said fixed valve seat permits fluid communication between said first and second ports, while preventing fluid communication between said second and third ports, and the closure of said movable valve seat permits fluid communication between said second and third ports, while preventing fluid communication between said first port and said second port.

16. An improved inline poppet valve assembly, comprising: a housing having an axial bore; first and second fixed valve seats disposed in the bore of said housing; first and second movable valve seats disposed in the bore of said housing; and first and second poppet valve members secured to an actuatorthatis axially movable within the bore of said housing, each of said poppet valve members having first and second sealing surfaces; said first sealing surface of said first poppet valve member being formed to close said first fixed valve seat and said second sealing surface of said second poppet valve member being formed to close said second movable valve seat in response to the articulation of said actuator in one direction;; said second sealing surface of said first poppet valve member being formed to close said first movable valve seat and said first sealing surface of said second poppet valve member being formed to close articulation of said actuator in the opposite said second fixed valve seat in response to the direction.

17. A poppet valve assembly as set forth in Claim 16 wherein said housing is formed with an inlet port, first and second outlet ports, and first and second exhaust ports, said ports being disposed in relation to said poppet valve members such that: the closure of said first fixed valve seat permits fluid communication between said inlet port and said first outlet port while preventing fluid communication between said first outlet port and said first exhaust port, the closure of said second movable valve seat permits fluid communication between said second outlet port and said second exhaust port, while preventing fluid communication between said inlet port and said second outlet port, the closure of said first movable valve seat permits fluid communication between said first outlet port and said first exhaust port, while preventing fluid communication between said inlet port and said first outlet port, and the closure of said second fixed valve seat permits fluid communication between said inlet port and said second outlet port, while preventing fluid communication between said second outlet port and said second exhaust port.

18. A poppet valve assembly as set forth in Claim 17 wherein said first sealing surfaces of said first and second poppet valve members each define surface areas of a first predetermined size, and said second sealing surfaces of said first and second poppet valve members each define surface areas of a second predetermined size.

19. A poppet valve assembly as set forth in Claim 18 wherein said first predetermined surface areas are greater than said second predetermined surface areas.

20. A poppet valve assembly as set forth in Claim 19 wherein each of said sealing surfaces generally comprise a continuous annular rib of elastomeric material.

21. A poppet valve assembly substantially as described herein with reference to and as illustrated in the accompanying drawings.