US3749127A - Fast acting,low pressure,two positioned valve - Google Patents

Abstract

A low pressure, fast acting valve assembly employs a poppet valve member which can rapidly move between two positions in order to control the on-off operation of the valve. The valve inlet conduit is positioned so that primary fluid stream impinges directly on the inlet side surface of the poppet valve forcing the poppet valve to the opened position. A fluid passage centrally positioned in the poppet valve permits a portion of the primary fluid to pass through the poppet valve to a control chamber. When a control fluid is supplied to the valve assembly, the control chamber outlet is closed, and pressure within the control chamber causes a diaphragm to move the poppet valve to the closed position. The surface area of the diaphragm is substantially greater than that of the aforenoted inlet side surface of the poppet valve thus providing a pressure differential so the poppet valve can move against the force of the primary fluid stream. The control chamber outlet is controlled by a diaphragm mechanism, so that a very low pressure control fluid can control the flow of the relatively high pressure primary fluid. With the poppet valve in the closed position, the outlet conduit is in communication with an exhaust conduit which permits reverse flow from the outlet conduit to the exhaust conduit.

Description

United States Patent 11 1 1111 3,749,127

Beeken et al. [4 July 31, 1973 FAST ACTING, LOW PRESSURE, TWO Primary Examiner-Henry T. Klinksiek POSITIONED VALVE Assistant Examiner-Robert J. Miller [75] Inventors: Basil B. Beeken, New Haven; Atmmey Alan Levine Vladimir lgnatjev, Norwalk, both of 57 ABSTRACT [73] Asslgnea: 3 g??? Switch Fora-Ham A low pressure, fast acting valve assembly employs a M poppet valve member which can rapidly move between two positions in order to control the on-off operation [22] Filed: Oct. 18, 1971 of the valve. The valve inlet conduit is positioned so [2]] App! 190066 that primary fluid stream impinges directly on the inlet side surface of the poppet valve forcing the poppet 521 US. 01. 137/6255, l37/625.27 valve to the Opened position A fluid Passage centrally 51 1m. 01. Fl6k 31/385, Fl6k 11 07 positioned in the P pp valve Permits a Portion of the [58] Field of Search 137/625.66, 625.27, p y fluid to p through the P pp valve to a 137/62525, 625,26, 625 62551; 251 23 trol chamber. When a control fluid is supplied to the 43 46 13 valve assembly, the control chamber outlet is closed,

and pressure within the control chamber causes a diaphragm to move the poppet valve to the closed posi- [56] References Cited UNITED STATES PATENTS tion. The surface area of the diaphragm 1s substantlally 2 722 234 11/1955 Mac em e e a 37/625 6 greater than that of the aforenoted 1nlet side surface of 33191022 7/1970 Kwafigho chungthe poppet valve thus providing a pressure differentlal 3,530,894 9 1970 Henzgen 137/6256 valve aganst the force h 3,670,771 (M972 Dewberry 37/6216 primary fluid stream. The control chamber outlet is 137,625.25 controlled by a diaphragm mechanism, so that a very 3,077,207 2/1963 Koutnik 137 255 low pressure control fluid can control the flow of the 2,964,057 12/1960 Dyson.....

3,653,408 4/1972 C0iner..... l37/625.6 relatively high pressure primary fluid. With the poppet ,2 6/1967 saim-Joanis et a l37/625.27 X valve in the closed position, the outlet conduit is in 3,263,702 8/1966 Pullen 6t 8] 137/62527 communicatibn an exhaust conduit which permits reverse flow from the outlet conduit to the exhaust conduit.

10 Claims, 5 Drawing Figures Patented July 31, 1973 5 Sheets-Sheet 2 FIG.2

Patented July 31, 1973 3,749,127

5 Sheets-Sheet 3 INVENTORS VLAD\ Ml R IGNATJEV ATTORNEY Patented July 31, 1973 5 Sheets-Sheet 4 FIG. 4

INVENTORS VLADIMIR IGNATJEV BASIL BI BEEKEN III Hill!!! I Patented July 31, 1973 3,749,127

5 Sheets-Sheet 5 FIG. 5

INVENTORS VLADIMIR IGNATJEV BASIL B. BEEKEN jZMNAA ATTORNEY FAST ACTING, LOW PRESSURE, TWO POSITIONED VALVE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to valve devices and more particularly to pilot operated two-position valves.

2. Brief Description of the Prior Art Fluidic amplifiers are frequently employed in conjunction with two-position valves which typically must be extremely fast acting, and which can operate at low pressures. Typically, such valves require springs in order to bias the valve in the closed position. A main air supply, typically a portion of the primary fluid, is employed to apply pressure to a diaphragm in order to maintain the valve in the opened position. The minimum operating pressure is typically in the order of at least five pounds per square inch (psi) and frequently as high as 20 psi because of the need to overcome the mechanical resistance of the spring used to bias the valve in the closed position.

SUMMARY OF THE INVENTION It has now been found that a fluid valve can be made to operate at extremely low pressures and with extremely short periods of response by using only fluid pressure to bias the valve in the open and closed positions.

In accordance with the present invention, a valve assembly is provided having an inlet conduit, and a valve chamber aligned with the inlet conduit. A valve member is positioned in the valve chamber and is provided with a fluid passage which is aligned with the inlet conduit. A diaphragm in a diaphram chamber is fixed to the valve member for movement with the valve member. A control means is provided for controlling flow from an outlet conduit of the diaphragm chamber, in response to the presence or absence of a control fluid.

The inlet to the valve members fluid passage is in a surface of the valve which lies in a plane substantially normal to the direction of flow of fluid exiting the inlet conduit.

BRIEF DESCRIPTION OF THE DRAWINGS The objects and features of the invention will become apparent from the following description particularly when taken in conjunction with the drawings wherein:

FIG. I is a cross-sectional view of a two position valve in accordance with the present invention, the valve being shown in the on position;

FIG. 2 is a cross-sectional view of the valve assembly of FIG. 1, showing the valve in the off position;

FIG. 3 is a cross-sectional view of another modificaiton ofa valve in accordance with the present invention, the valve being shown in the open position;

FIG. 4 is a cross-sectional view of the valve assembly of FIG. 3, showing the valve in the closed position; and

FIG. 5 is a cross-sectional view of still another modification of a valve of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION The valve assembly, shown generally as 10, is provided with an inlet conduit 12. The primary fluid stream indicated as Is travels through the inlet conduit 12 to the valve chamber I5 and then out of the valve assembly I0, via the outlet conduit I7.

A valve I6, such as a poppet valve, is positioned within the valve chamber and is free to move within the chamber. An O"-ring 59 is located at the inlet end of the valve chamber 15 and cooperates with the poppet valve to close the primary fluid inlet conduit I2.

A second O-ring I9, is positioned downstream of the O-ring 5% and cooperates with the poppet valve 16 to close the exhaust conduit 34. It is noted that the exhaust conduit can consist of an outlet 33 and a restrictor region 35 which limits the flow rate of the exhaust fluid.

Fluid pressure as indicated by the arrows II, acting against the surface I4 on the inlet side of the poppet valve 16 tends to keep the poppet valve in a position wherein the lower surface 18 of the flange portion 20 of the poppet valve presses and seals against the O- ring seal 19. The resultant sealing arrangement between the lower flange surface 18 and the O"-ring seal 19 precludes flow of fluid between the inlet conduit I2 and the valve chamber 31.

A small portion of the primary fluid flow, as indicated by the arrows 22, leads through the Venturi-type longitudinal passage 25 in the'poppet valve 16, into the diaphragm chamber 21. The fluid then exits from the diaphram chamber 21 through the nipple 24 into the control chamber 23. The fluid in the control chamber 23 exits from the valve assembly 10 via the outlet 26 of the restrictor 27. Fluid pressure in the control chamber 23, as indicated by the arrows 28, applies pressure to the control chamber side 30 of the valve control diaphragm 32, thus maintaining the valve control diaphragm 32 in a position away from the nipple 24'and permitting flow through the nipple.

It is thus seen that when the valve assembly 10 is in its first or on position, the poppet valve I6 is maintained in a position such that a small amount of fluids bleeds from the valve assembly 10 through the restrictor outlet 26, while the primary portion of fluid exits from the valve assembly 10 through the outlet conduit 17.

The fluid pressure of the primary fluid stream Ps against the poppet valve inlet surface 14 is greater than the fluid pressure within the diaphragm chamber 21 and the control chamber 23, thus closing the outlet 33.

As shown in FIG. 2, when a control fluid Pc is supplied to the control port 40, the control diaphram 32 is caused to move towards the lower surface 42 of the nipple 24, thus preventing fluid from flowing out of the control chamber 23. Fluid pressure against the diaphragm chamber diaphram 46 rapidly causes the poppet valve 16 to move in the direction of the O-ring 59 thereby sealing the upper surface 14 against the O-ring 59 and precluding fluid communication between the inlet conduit I2 and the outlet conduit I7.

The rapidity of the closing action of the poppet valve 16 is controlled, at least in part, by virtue of the fact that the poppet valve passage inlet 44 and the longitudinal axis of the poppet valve passage 25 are directly in line with the direction of flow of the primary fluid stream Ps. The greater the diameter of the poppet valve passage inlet opening 44, the faster is the closing action of the poppet valve since the fluid flowing into the sealed diaphragm chamber 2] brings about the closing action. The air flow through the poppet valve I6 and then through the restrictor 26 constitutes an air loss. The air loss increases with the square of the diameter of the passage, and consequently it is desirable to use the smallest poppet valve passage diameter and inlet diameter consistant with the required response time. The poppet valve passage diameter is preferably in the range from 0.013 to 0.020 inches. For example, the response time of 19 milli-seconds can be achieved with a poppet valve inlet opening of the 0.015 inches in diameter. Of course, dimension changes will influence response time.

It is apparent that a certain minimum control fluid pressure is required in order to overcome the pressure exerted by the fluid attempting to exit through the nipple 24. The cross-sectional area of the nipple opening 29 is substantially smaller than the effective surface area of the control diaphragm 32. Accordingly, the control fluid pressure can be substantially smaller than the pressure of the primary fluid stream. With a primary fluid stream inlet pressure of 5 psi, a control fluid pressure of 0.2 or 0.3 psi can be used. For greater primary fluid pressures, a pressure isolater can be employed in order to permit the use of the very low control fluid pressures.

The difference in effective cross-secitonal area of the poppet valve surface 14 and the valve control diaphram 46 affectively influences the speed of response. Another factor of consequence at this point is the flow rate which is permitted through the poppet valve passage 25. Inasmuch as the poppet valve surface 14 sees substantially the full primary fluid pressure, the effective cross-sectional area of the valve control diaphram must be substantially greater than that of the surface 14. A diameter ratio of about 2 to I can be employed in order to give the proper operating characteristics. From the standpoint of surface area the ratio is preferably about 3 to l, but can be from 2.5 to I, to 3.5 to I.

As shown in FIG. 3, the valve assembly indicated generally as 60 can employ a poppet valve 66 which correspondes essentially to the poppet valve 16 of the valve assembly 10. However, in this case, the poppet valve passage 65 is not of the Venturi design but rather has a small diameter, inlet section 64, and a larger diameter, downstream section 67. As previously noted in regard to the design of FIG. 1 and 2, the diameter of the inlet 64 of the poppet valve 66 effectively controls response time.

In the valve of FIG. 3, the primary fluid Ps enters the inlet conduit 72 and applies pressure against the inlet side surface 74 of the poppet valve 66. This pressure causes the poppet valve to move away from the inlet conduit 72 and towards the diaphragm chamber 73. In order to achieve the maximum effect of the primary fluid stream Ps on the poppet walve 66, it is essential to have the primary fluid impact directly against the poppet valve surface 74 and that the axis of the inlet conduit 72 be aligned with the axis of the central passage 65 of the poppet valve 66.

The conduit section 78 provides for a fluid flow which is substantially at a right angle to the direction of fluid flow to the inlet conduit 72 in order to maximize the desired flow relationships.

The kinetic energy of the primary fluid Ps acts against the surface 74 of the poppet valve 66 in order to rapidly drive the valve to the open position. The closing operation is also influenced by the driving force of the primary fluid because of the alignment of the central axis of the inlet conduit 72 and the central passage 65 of the poppet valve 66. In the modification of the valve assembly 60, of FIG. 3, a filter element 80 is employed as the restricting means for limiting the flow rate of fluid from the control chamber 83. The outlet passage 84 which permits the flow of the fluid from the filter to the ambient is typically maintained sufficiently large so that the filter is the limiting factor of the flow rate.

As shown in FIG. 4, the application of a control fluid to the control fluid inlet applies a pressure agianst the control diaphragm 32 thereby closing the control chamber outlet 94. The pressure build up within the control chamber 73 applies pressure against the diaphragm chamber diaphram 96 rapidly forcing the poppet valve 66 to an upward position in which the outer, upper edge 98 of the fluid inlet side surface 74 mates with the O-ring 59, thereby precluding flow between the fluid inlet conduit 72 and the fluid outlet conduit Communication, however, is established between the fluid outlet conduit 77 and the exhaust conduit 100, thereby permitting an exhausting of fluid through the outlet conduit 77 and the clearance region 1012 which is between the outer surface of the poppet valve 66 and the inner surface of the housing or the body portion of the valve assembly 60. It should be noted that a substantial clearance is required in order to permit the flow of the exhaust fluid from the outlet conduit 77 to the exhaust conduit l00.-A plurality of ribs or fins 102 can be used to center the poppet valve.

It can be seen in FIG. 4, that the control chamberdiaphram 32, is held in place between concentric circular protrusions lltl and 112. The circular protrusion is provided with a discontinuity or open region I14 through which fluid, indicated by arrows 116, can flow from the control chamber conduit 118 to the filter 80, and the outlet passage 84. The surface area of the control chamber-diaphragm 32, which is exposed to the control fluid Pc, should be substantially greater than the surface area of the control chamber conduit opening 94, so that a low control fluid pressure can be effectively employed.

The plane of the lower surface of the control chamber conduit 118 must be at a slight angle with respect to the normal plane of the control chamber diaphram 32. The diaphram 32 can tend to hang-up" in the closed position when parallel planes are used. An excessive non-parallel alignment can, however, interfere with proper sealing of the diaphram. An angle of from 3 to 8 bet-ween the two planes has been found to afford the desired results.

It can be seen in FIG. 5, that the valve member can be in the form of an elongated member. The valve is shown in the position in which the shoulder I30 engages an O-ring 132, thereby closing the exhaust conduit 134. In the position shown in FIG. 5, the inlet conduit 136 and the outlet conduit 138 are in communication. However, when a control fluid is supplied to the control fluid conduit 140, the pressure on the diaphram 142 closes the diaphram chamber outlet conduit 144 in the manner previously noted, and the pressure in the diaphram chamber 146 immediately causes the valve 125 to move upwardly until the upper surface 128 of the valve seats against the O"-ring 148.

In this latter position, the communication between the inlet conduit 136 and the outlet conduit 138 is closed, but the primary fluid continues to vent slowly through the restrictor 150 and the exhaust conduit I34 and the outlet conduit 138 are in communication. In

this regard, it is noted that the narrowed down region 152 of the valve 125 provides for clearance between the valve 125 and the O-ring 132 when the valve is in its upper position. The clearance permits fluid to flow between the interior wall 154 of the valve chamber 156 and the exterior of the valve 125. The valve assembly of FIG. 5 functions in all other respects in the same manner as the valves of FIGS. l-4.

What is claimed is:

l. A valve comprising:

a valve body,

a fluid inlet conduit, formed in said body, extending from an exterior surface of said body to the interior of said body along a straight longitudinal axis,

a fluid outlet formed in said body,

a valve member movable between a first position in which flow is permitted between said inlet and outlet and a second position in which flow is prevented between said inlet and outlet,

said valve member having a surface arranged transverse to and in alignment with the longitudinal axis of said inlet conduit, said surface being exposed to fluid flowing into said valve body through said inlet conduit,

a fluid passage extending through the interior of said valve member, said passage having a longitudinal axis coaxial with the longitudinal axis of said inlet conduit, whereby fluid entering said inlet passageway flows in a straight line through said inlet passageway and said fluid passage in said valve member,

a chamber in said valve body for receiving fluid leaving said fluid passage,

vent means in said valve body for venting fluid from said chamber, I

control means for selectively interrupting venting of fluid through said vent means so that fluid pressure builds up in said chamber, and

means responsive to the build up of pressure in said chamber for moving said valve means from one of its positions to the other.

2. A valve as defined in claim 1 wherein said control means includes a control conduit through which fluid flows out of said chamber, and a control diaphragm movable into and out of engagement with said control conduit to control the flow of fluid therefrom.

3. A valve as defined in claim 2 including a control chamber into which fluid from said control conduit exits, and a control fluid inlet into said control chamber, said control diaphragm being arranged between said control inlet and said control conduit and being responsive to fluid pressure at said control inlet for engaging said control conduit to prevent flow through the latter.

4. A valve as defined in claim 2 wherein said control conduit has a surface which is engaged by said control diaphragm to prevent flow through the control conduit, said surface being arranged at an actue angle to said control diaphragm when the latter is relaxed and out of engagement with said surface.

5. A valve as defined in claim 4 wherein the acute angle is between 3 and 8.

6. A valve as defined in claim 1 wherein said fluid passage extending through said valve member has a relatively small cross-sectional area in a region closer to said inlet conduit and a relatively large cross-sectional area downstream of said region.

7. A valve as defined in claim 1 wherein said fluid passage extending through said valve member has an inlet in said valve member surface, said inlet having a diameter on the order of 0.013 to 0.020 inch.

8. A valve as defined in claim 1 wherein said responsive means includes a diaphragm secured to said valve member, said diaphragm being exposed to the pressure of fluid flowing through said valve member passage when flow through said vent means is interrupted, and the ratio of the cross-sectional area of (l) said valve member surface exposed to fluid from said inlet conduit, and (ll) the combined area of the exposed diaphragm surface and the other end of said valve member, is in the range of 2.5:l to 35:1.

9. A valve as defined in claim 1 including an exhaust conduit, and wherein in its first position said valve member permits flow between said inlet and outlet conduits but prevents flow between said outlet and exhaust conduits, and in its second position said valve member permits flow between said outlet and exhaust conduits but prevents flow between said inlet and outlet conduits.

10. A valve as defined in claim 9 including restrictor means for limiting the rate of fluid flow through said exhaust conduit.

Claims (10)

1. A valve comprising: a valve body, a fluid inlet conduit, formed in said body, extending from an exterior surface of said body to the interior of said body along a straight longitudinal axis, a fluid outlet formed in said body, a valve member movable between a first position in which flow is permitted between said inlet and outlet and a second position in which flow is prevented between said inlet and outlet, said valve member having a surface arranged transverse to and in alignment with the longitudinal axis of said inlet conduit, said surface being exposed to fluid flowing into said valve body through said inlet conduit, a fluid passage extending through the interior of said valve member, said passage having a longitudinal axis coaxial with the longitudinal axis of said inlet conduit, whereby fluid entering said inlet passageway flows in a straight line through said inlet passageway and said fluid passage in said valve member, a chamber in said valve body for receiving fluid leaving said fluid passage, vent means in said valve body for venting fluid from said chamber, control means for selectively interrupting venting of fluid through said vent means so that fluid pressure builds up in said chamber, and means responsive to the build up of pressure in said chamber for moving said valve means from one of its positions to the other.

2. A valve as defined in claim 1 wherein said control means includes a control conduit through which fluid flows out of said chamber, and a control diaphragm movable into and out of engagement with said control conduit to control the flow of fluid therefrom.

3. A valve as defined in claim 2 including a control chamber into which fluid from said control conduit exits, and a control fluid inlet into said control chamber, said control diaphragm being arranged between said control inlet and said control conduit and being responsive to fluid pressure at said control inlet for engaging said control conduit to prevent flow through the latter.

4. A valve as defined in claim 2 wherein said control conduit has a surface which is engaged by said control diaphragm to prevent flow through the control conduit, said surface being arranged at an actue angle to said control diaphragm when the latter is relaxed and out of engagement with said surface.

5. A valve as defined in claim 4 wherein the acute angle is between 3* and 8*.

6. A valve as defined in claim 1 wherein said fluid passage extending through said valve member has a relatively small cross-sectional area in a region closer to said inlet conduit and a relatively large cross-sectional area downstream of said region.

7. A valve as defined in claim 1 wherein said fluid passage extending through said valve member has an inlet in said valve member surface, said inlet having a diameter on the order of 0.013 to 0.020 inch.

8. A valve as defined in claim 1 wherein said responsive means includes a diaphragm secured to said valve member, said diaphragm being exposed to the pressure of fluid flowing through said valve member passage when flow through said vent means is interrupted, and the ratio of the cross-sectional area of (I) said valve member surface exposed to fluid from said inlet conduit, and (II) the combined area of the exposed diaphragm surface and the other end of said valve member, is in the range of 2.5:1 to 3.5:1.

9. A valve as defined in claim 1 including an exhaust conduit, and wherein in its first position said valve member permits flow between said inlet and outlet conduits but prevents flow between said outlet and exhaust conduits, and in its second position said valve member permits flow between said outlet and exhaust conduits but prevents flow between said inlet and outlet conduits.

10. A valve as defined in claim 9 including restrictor means for limiting the rate of fluid flow through said exhaust conduit.

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