WO2012126182A1

WO2012126182A1 - Balanced axial flow pressure regulator

Info

Publication number: WO2012126182A1
Application number: PCT/CN2011/072102
Authority: WO
Inventors: Shihuai SHU; Yantao SUN; Yunxia HAN
Original assignee: Fisher Regulators (Shanghai) Co., Ltd.
Priority date: 2011-03-24
Filing date: 2011-03-24
Publication date: 2012-09-27

Abstract

A balanced axial valve assembly includes a control member disposed within a valve body and movable relative to a valve port to control fluid flow through the valve body. A sliding stem is operatively connected to the control member with a hinged bracket. The assembly further includes a base body having a central bore and a plug, one end of the base body forming a valve seat. The control member is mounted on the base body and moves towards and away from the valve seat to control fluid flow through the valve body. The control member moves parallel to a fluid flow path through the valve body.

Description

BALANCED AXIAL FLOW PRESSURE REGULATOR

FIELD OF THE INVENTION

The present invention relates generally to fluid regulators and, more specifically, to axial flow fluid regulators having a balanced trim assembly.

BACKGROUND

Regulators are commonly employed in fluid or gas distribution systems to control the pressure in the system downstream of the regulator. As is known, the pressure at which a typical gas distribution system supplies gas may vary according to the demands placed on the system, the climate, the source of the supply, and/or other factors. However, most end-user facilities equipped with, for example, gas appliances such as furnaces, ovens, etc., require the gas to be delivered in accordance with predetermined pressure parameters. Therefore, such distribution systems use regulators to ensure that the delivered gas meets the requirements of the end-user facilities.

In fluid or gas regulators (collectively "fluid regulators"), a number of design and performance considerations may be important. For example, designers of fluid regulators may strive to design regulators having greater pressure stability and reduced sensitivity to inlet pressure variations. Further, designers may strive to construct more compact designs, and designs which might favor easy assembly and service.

Several types of fluid regulators are known, for example, sliding stem regulators, rotary regulators, etc. In some regulators, such as the sliding stem regulator and rotary actuator, fluid flow through the valve is turned by 90 degrees or more as the fluid passes through a valve seat. The 90 degree turn is necessary because an actuator for the valve is oriented generally perpendicular to the fluid flow direction and a valve plug is oriented parallel to actuator movement (i.e., perpendicular to the fluid flow direction) to simplify the actuator- valve plug interface. However, in some applications some sliding stem and rotary regulators may suffer from vibration and loss of valve efficiency due to the turning fluid flow path through the regulator. Axial or in-line flow control valves are an alternative to sliding stem and rotary control valves. Axial flow valves have a flow path or passageway through the valve that is substantially straight or parallel to the fluid flow direction to minimize turbulent flow through the valve body. Axial flow control valves typically include an actuator mounted to an exterior surface of the valve body. The actuator is operatively coupled to a flow control member of the valve and moves the flow control member between an open position and a closed position to allow or prevent the flow of fluid through the valve. Some known axial flow control valves actuate a flow control member within the valve body relative to a seat ring to control fluid flow through the valve body.

However, axial flow regulators are often unbalanced. Unbalanced configurations result in increased inlet sensitivity, plug vibration, and low flow coefficients, especially at higher pressures. As a result, high pressure axial flow regulators are not often employed in high pressure operations.

SUMMARY

In accordance with an aspect of the invention, a fluid flow regulating device includes a balanced axial valve assembly having a control member disposed within a valve body and movable relative to a valve port to control fluid flow through the valve body. A sliding stem is operatively connected to the control member with a hinged bracket. The assembly further includes a base body having a central bore and a plug, one end of the base body forming a valve seat. The control member is mounted on the base body and moves towards and away from the valve seat to control fluid flow through the valve body. The control member moves parallel to a fluid flow path through the valve body.

In accordance with one or more preferred forms, the control member may include a blind bore for receiving the plug. The control member sliding on the plug towards and away from the valve seat.

In accordance with another aspect, the control member may include a skirt terminating in a chamfered surface. In accordance with an additional preferred form, the control member may include a central bore for receiving a portion of the base body, and the valve seat is formed on the plug, the control member being slidably attached to the base body.

In accordance with another aspect, the control member may be connected to the hinged bracket with a retainer including a fork-shaped body and two spaced apart legs.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a cross-sectional view of an axial flow fluid regulating device including a balanced regulator assembly.

Figure 2 is close-up cross-sectional view of the balanced regulator assembly of Figure 1.

Figure 3 is a perspective view of the balanced regulator assembly of

Figure 2.

Figure 4 is an enlarged fragmentary perspective view of the balanced regulator assembly of Fig. 2.

Figure 5 is a cross-sectional view of an axial flow regulator having another embodiment of a balanced regulator assembly.

Figure 6 is a close-up cross-sectional view of the balanced regulator assembly of Figure 5.

Figure 7 is a perspective view of the balanced regulator assembly of

Figure 6.

Figure 8 is an enlarged fragmentary perspective view of the balanced regulator assembly of Figure 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, Figure 1 illustrates an axial flow fluid regulating device assembled in accordance with the teachings of a first disclosed example of the present invention and referred to by the reference numeral 10. The fluid regulating device 10 includes a valve body 12 including a valve inlet 14, a valve outlet 16, and a valve port 18. A cylindrical control element 20 is shiftably disposed within the valve body 12, such that the control element 20 can be displaced relative to the valve port 18 in order to control the flow of the fluid between the inlet 14 and the outlet 16. The valve port 18 typically includes a valve seat 19. As would be understood by those of skill in the art, control of fluid through the fluid regulating device can be controlled by moving the control element 20 between the open position as shown in Figure 1 in which the control element 20 is spaced away from the valve seat 19, and a closed position (not shown) in which the control element 20 is seated against the valve seat 19.

The fluid regulating device 10 further includes an actuator 38 which, in the example shown is a pneumatic diaphragm-type actuator of the type commonly employed in the art. Other actuators may prove suitable. An L-shaped hinged bracket 40 is mounted within the valve body 12 in order to operatively couple the actuator 38 to the control element 20 through a valve stem 22. The hinged bracket 40 includes a first portion 41 and a second portion 42 oriented substantially perpendicularly to one another. The hinged bracket 40 multiplies forces from the actuator 38, which results in the ability to use smaller diaphragms and thus more compact actuators at lower pressure settings. The first portion 41 is directly attached to the valve stem 22 and moves with the valve stem 22. The second portion 42 is directly attached to the control member 20 and actuates the control member 20 as the valve stem 22 moves the first portion 41. The first and second portions 41, 42 are both attached to a hinge 44 that is pivotable about a pivot point 45. The hinged bracket 40 changes a direction of actuator force by approximately 90 degrees. In the example illustrated in Figure 1, the actuator 38 moves the valve stem 22 in a substantially vertical direction in response to pressure differences within an actuator housing 50. As the valve stem 22 moves vertically, the hinged bracket 40 pivots about the pivot point 45, thus actuating the control member 20 in a substantially horizontal direction, substantially parallel to a direction of fluid flow. Orienting the control member 20 substantially parallel to the direction of fluid flow simplifies the fluid flow path, which lowers flow resistance leading to relatively high flow coefficients. As the hinged bracket 40 moves in response to the actuator 38, the second portion 42 of the hinged bracket 40 pushes and pulls the control member 20 towards and away from the valve seat 19. Thus, fluid flow through the valve body 12 is throttled by the control member 20, which is positioned by the actuator 38, and the control member 20 moves substantially parallel to fluid flow through the valve body 12. In the embodiment of Figure 1, the hinged bracket 40 is located downstream of the valve seat 19.

Referring now to Figures 2-4, a balanced valve assembly includes the control element 20 and a valve seat base 60. The control element 20 moves relative to the valve seat 19 on the valve seat base 60 to permit or restrict fluid flow through the valve body 12 (Figure 1). The valve seat base 60 includes a base body 62 having a hollow central bore 64 and an annular mounting flange 65. The annular mounting flange 65 may receive fasteners (not shown) to secure the valve seat base 60 to the valve body 12 (Figure 1). Fluid enters a first end 66 of the hollow central bore 64 and exits through a second end 68 of the hollow central bore 64. The valve seat 19 is formed by the base body 62 proximate the second end 68 of the hollow central bore 64. The valve seat base 60 also includes a cylindrical plug 70 that is spaced apart from the valve seat 19. The plug 70 may be connected to the base body 62 by one or more pillars 72. The plug 70 may include an outer circumference that is larger than the hollow central bore 64.

The control member 20 includes a control body 80 having a blind bore 82. The blind bore 82 includes an internal wall 84 that is sized to receive the plug 70. The control body 80 also includes a skirt 86 extending from a first end 88 to a second end 90 of the control body 80. The skirt 86 terminates in a chamfered end surface 92 that cooperates with the valve seat 19 to control fluid flow through the valve body 12 (Figure 1).

When the control member 20 is in an open position, as illustrated in Figure 2, fluid flow (represented by arrows A) enters the base body 62 at the first end 66 and flows through the central bore 64 and out the second end 68 of the base body 62, between the valve seat 19 and the chamfered end surface 92. The plug 70 may include one or more seals, such as an o-ring 94, disposed in an annular channel 95 formed in the outer circumference. The o-ring 94 prevents fluid from flowing around the plug and though openings 98 in the control member 20 when the control member 20 is in a closed position. The openings 98 in the control member equalize fluid pressure between the blind bore 82 and the fluid flow passage in the valve body 12. The openings 98 balance fluid pressure between the outlet side of the valve seat 19 and the blind bore 82 within the control member 20. The openings 98 produce a balanced trim arrangement, which is less susceptible to changes in inlet and outlet pressure. The control member 20 may also include a substantially cylindrical peg 99 extending from one end, the peg 99 including a connection portion, such as a depression 100, that connects the control member to the second portion 42 of the hinged bracket 40 (Figure 1).

The base body 62 may also include one or more seals, such as o-rings 96, disposed in annular channels 97 formed in an outer circumference of the base body 62. The o-rings 96 provide a fluid seal between the base body 62 and the valve body 12.

In the embodiment of Figures 1-4, the hinged bracket 40 is located downstream in a direction of fluid flow with respect to the control member 20, and the control member 20 is located downstream of the valve seat 19. As a result, fluid flow tends to push the control member 20 away from the valve seat 19 and towards the open position. Thus, opening forces are relatively light in this embodiment. The embodiment of Figures 1-4 is well suited for pressure reducing, dome, and vacuum breaker applications.

Referring now to Figure 5, an axial flow fluid regulating device assembled in accordance with the teachings of a second disclosed example of the present invention and referred to by the reference numeral 110 is illustrated. The fluid regulating device 110 includes a valve body 112 including a valve inlet 114, a valve outlet 116, and a valve port 118. A cylindrical control element 120 is shiftably disposed within the valve body 112, such that the control element 120 can be displaced relative to the valve port 118 in order to control the flow of the fluid between the inlet 114 and the outlet 116. The valve port 118 typically includes a valve seat 119. As would be understood by those of skill in the art, fluid flow through the fluid regulating device can be controlled by moving the control element 120 between the open position as shown in Figure 5 in which the control element 120 is spaced away from the valve seat 119, and a closed position (not shown) in which the control element 120 is seated against the valve seat 119.

The fluid regulating device 110 further includes an actuator 138 which, in the example shown is a pneumatic diaphragm-type actuator of the type commonly employed in the art. Other actuators may prove suitable. An L-shaped hinged bracket 140 is mounted within the valve body 112 in order to operatively coupled the actuator 138 to the control element through a valve stem 122, with the hinged bracket including a first portion 141 and a second portion 142 oriented substantially perpendicularly to one another. The first portion 141 is directly attached to the valve stem 122 and the second portion 142 is indirectly attached to the control member 120 by a retainer 121. The first and second portions 141, 142 are both attached to a hinge 144 that is pivotable about a pivot point 145. The hinged bracket 140 changes a direction of actuator force by approximately 90 degrees. In the example illustrated in Figure 5, the actuator 138 moves the valve stem 122 in a substantially vertical direction in response to pressure differences within an actuator housing 150. As the valve stem 122 moves vertically, the hinged bracket 140 pivots about the pivot point 145, thus actuating the control member 120 in a substantially horizontal direction, substantially parallel to a direction of fluid flow. The hinged bracket 140 is mounted upstream of the valve seat 119 in this embodiment.

Referring now to Figures 6-8, a balanced valve assembly includes the control element 120, a retainer 171, and a valve seat base 160. The control element 120 moves relative to the valve seat 119 on the valve seat base 160 to permit or restrict fluid flow through the valve body 112 (Figure 5). The valve seat base 160 includes a two-piece base body 162 including first and second body pieces 162a 162b having a hollow central bore 164 and an annular mounting flange 165 located on the first body piece 162a. The first and second body pieces 162a, 162b may be secured to one another via threaded sections 167. The annular mounting flange 165 may receive fasteners (not shown) to secure the valve seat base 160 to the valve body 112 (Figure 5). Fluid enters a first end 166 of the hollow central bore 164 and exits through a second end 168 of the hollow central bore 164. The valve seat 119 is formed on a substantially cylindrical plug 170 that is spaced apart from the second body piece 162b by one or more pillars 172. The plug 170 may include an outer circumference that is larger than the hollow central bore 164. The valve seat 119 may include a chamfered surface 177 on one side of the plug 170. One or more seals, such as o- rings 194 may be located proximate the valve seat 119, the o-rings enhancing a seal between the valve seat 119 and the control member 120 when the control member 120 is in a closed position.

The control member 120 includes a control body 180 having a central bore 182. The central bore 182 includes an internal wall 184 that is sized to receive the second body piece 162b, the control member 120 forming a sleeve at least partially disposed on the second body piece 162b. One end of the control member may terminate in a chamfered end surface 92 that cooperates with the valve seat 119 to control fluid flow through the valve body 112 (Figure 5). The control member 120 is slidable along the second body portion 162b between an open position (illustrated in Figure 6) in which the control member 120 is spaced a part from the valve seat 119 and a closed position (not shown) in which the control member 120 cooperates with the valve seat 119 to prevent fluid from flowing into the central bores 182 and 164.

When the control member 120 is in an open position, as illustrated in Figure 6, fluid flows (represented by arrows A) between the valve seat 119 and the chamfered surface 192, into the central bore 182 of the control member 120, and into the central bore 164 of the valve seat base 160.

The control member 120 is actuated by the retainer 121. The retainer 121 includes a fork-shaped body 123 having two legs 125. The legs 125 are spaced apart from one another and receive a portion of the second body piece 162b and a portion of the control member 120 in the space between the legs 125. Each leg receives a fastener 127 that secures the retainer 121 to the control member 120. The control member 120 may optionally include one or more channels 129 formed in an outer surface, the channels 129 may be sized to receive parts of the legs 125 so that the legs 125 are stabilized within the channels 129 and thus more resistant to vibration. The retainer 121 may also include a bore 200, for securing the retainer 121 to the second portion 142 of the hinged bracket 140 (Figure 5) so that the retainer 121 actuates with the hinged bracket 140. The valve seat base 160 may also include one or more seals, such as o-rings 196 disposed in annular channels 197 formed in an outer circumference of the base body 162. The o-rings 196 provide a fluid seal between the base body 162 and the valve body 12 and/or between the base body 162 and the control member 120.

As the hinged bracket 140 moves in response to the actuator 138, the second portion 142 of the hinged bracket 140 pushes and pulls the control member 120 towards and away from the valve seat 119. Thus, fluid flow through the valve body 112 is throttled by the control member 120, which is positioned by the actuator 138, and the control member 120 moves substantially parallel to fluid flow through the valve body 1 12. In the embodiment of Figure 5, the hinged bracket 140 is located upstream of the valve seat 119.

In the embodiment of Figures 5-8, the hinged bracket 140 is located upstream in a direction of fluid flow with respect to the valve seat 119 and the control member 120 is located downstream of the valve seat 119. As a result, fluid flow tends to push the control member 120 away from the valve seat 1 19 and towards the open position. Thus, opening forces are relatively light in this embodiment. The embodiment of Figures 5-8 is well suited for vacuum recovery applications.

In accordance with one aspect of the disclosed example, the balanced valve results in a more efficient control valve that experiences less inlet sensitivity when compared to prior axial flow valves. The reduced inlet sensitivity tends to dampen unstable conditions. Additionally, disclosed axial flow regulator is more compact than prior axial flow regulators.

Preferred embodiments of this invention are described herein, including the best mode or modes known to the inventors for carrying out the invention. Although numerous examples are shown and described herein, those of skill in the art will readily understand that details of the various embodiments need not be mutually exclusive. Instead, those of skill in the art upon reading the teachings herein should be able to combine one or more features of one embodiment with one or more features of the remaining embodiments. Further, it also should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the aspects of the exemplary embodiment or embodiments of the invention, and do not pose a limitation on the scope of the invention. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Claims

CLAIMS What is claimed is:

1. An axial flow control valve comprising: a valve body defining a passageway between an inlet and an outlet, wherein the passageway is substantially parallel to a fluid flow path at the inlet and the outlet of the valve body;

an actuator attached to the valve body for moving a valve stem;

a balanced valve assembly disposed within the valve body, the balanced valve assembly including a control member and a base body, the control member being located downstream of a valve seat formed on the base body; and

a hinged bracket disposed within the valve body, the hinged bracket being attached to the valve stem and to the control member, the hinged bracket moving in response to valve stem movement to actuate the control member; wherein the control member includes a blind bore and the base body includes a plug, the plug being received within the blind bore, the control member being movable relative to the valve seat to selectively admit or restrict fluid flow through the valve body.

2. An axial flow control valve as defined in claim 1, wherein the control member is movable substantially parallel to the fluid flow path.

3. An axial flow control valve as defined in any one of the preceding claims, wherein the hinged bracket is located downstream of the valve seat.

4. An axial flow control valve as defined in any one of the preceding claims, wherein the hinged bracket includes a first portion and a second portion, the first portion being oriented substantially perpendicular to the second portion.

5. An axial flow control valve as defined any one of the preceding claims, wherein the control member includes a control body having a skirt portion extending from one end of the control body.

6. An axial flow control valve as defined in any one of the preceding claims, wherein the skirt terminates in a chamfered surface.

7. An axial flow control valve as defined in any one of the preceding claims, wherein the base body includes a central bore.

8. An axial flow control valve as defined in any one of the preceding claims, wherein the plug has an outer circumference that is larger than the central bore.

9. An axial flow control valve as defined in any one of the preceding claims, wherein the plug is spaced apart from the valve seat by a pillar.

10. An axial flow control valve as defined in any one of the preceding claims, wherein the plug includes an o-ring disposed in an annular channel.

11. An axial flow control valve as defined in any one of the preceding claims, wherein the base body includes an o-ring disposed in an annular channel.

12. An axial flow control valve as defined in any one of the preceding claims, wherein the balanced valve assembly is mounted in one of a pressure reducing valve, a dome valve, and a vacuum breaker valve.

13. An axial flow control valve comprising: a valve body defining a passageway between an inlet and an outlet, wherein the passageway is substantially parallel to a fluid flow path at the inlet and the outlet of the valve body; an actuator attached to the valve body for moving a valve stem;

a hinged bracket disposed within the valve body, the hinged bracket being attached to the valve stem and to the control member, the hinged bracket moving in response to valve stem movement to actuate the control member;

wherein the control member includes a central bore and the base body includes a plug having a valve seat, the control member being slidably disposed on a portion of the base body, the control member being movable relative to the valve seat to selectively admit or restrict fluid flow through the valve body.

14 The axial flow valve of claim 13, wherein the balanced valve assembly is mounted in a vacuum breaker valve.

15. The axial flow valve of any one of claims 13 or 14, wherein the hinged bracket is located upstream of the valve seat.

16. The axial flow valve of any one of claims 13-15, wherein the base body includes a first body piece and a second body piece, the first and second body pieces being attached to one another with a threaded connection.

17. The axial flow valve of any one of claims 13-16, wherein the base body includes a central bore.

18. The axial flow valve of any one of claims 13-17, wherein an outer circumference of the plug is larger than the central bore.

19. The axial flow valve of any one of claims 13-18, further comprising a retainer coupling the hinged bracket to the control member.

20 The axial flow valve of any one of claims 13-19, wherein the retainer includes a fork-shaped body.

21. The axial flow valve of any one of claims 13-20, wherein the fork-shaped body includes two legs.

22. The axial flow valve of any one of claims 13-21, wherein the two legs are spaced apart from one another by a distance.

23. The axial flow valve of any one of claims 13-22, wherein a portion of the control member and a portion of the base body are received between the two forks.

24. The axial flow valve of any one of claims 13-23, wherein the control member includes a pair of channels formed in an outer surface and the two forks are at least partially disposed within the pair of channels.