CN112539290A

CN112539290A - Mechanical stop drain for fluid control device

Info

Publication number: CN112539290A
Application number: CN201910899887.5A
Authority: CN
Inventors: 闫剑; 类彦威; 时延波; 范国磊
Original assignee: Fisher Jeon Gas Equipment Chengdu Co Ltd
Current assignee: Fisher Jeon Gas Equipment Chengdu Co Ltd
Priority date: 2019-09-23
Filing date: 2019-09-23
Publication date: 2021-03-23

Abstract

Mechanical stop drain for a fluid control device. A fluid control device includes a control element that slides within a sleeve between an open position and a closed position. The travel of the control member within the sleeve is limited by interfering stop surfaces of the sleeve and the control member, thereby preventing the control member stop surfaces from sliding past the sleeve stop surfaces. The vent fluidly couples a space existing between the sleeve and the control element with an interior of the control element.

Description

Mechanical stop drain for fluid control device

Technical Field

The present invention relates to a fluid control device, and more particularly to a mechanical stop drain system for a fluid control device.

Background

An emergency shutdown valve is a type of valve that is quickly actuated (e.g., quickly closed when an emergency condition occurs) in the event of a detected process condition. Typically, a slam shut valve includes a valve and a slam shut trigger mechanism that can actuate a control element to rapidly shut off the flow path of the valve when a process condition reaches a fixed set point. When certain fixed set points are met, the emergency shutdown valve shuts off fluid to protect downstream components in the system. When the system returns to normal operation, a manual reset shut-off is required to open the valve.

Disclosure of Invention

Disclosed is a fluid control apparatus, including: a sleeve including a first stop surface; a control element configured to slide within the sleeve between a first position in which the control element engages a valve seat to restrict fluid flow through the fluid control device and a second position in which the control element is spaced from the valve seat to allow fluid flow through the fluid control device, wherein the control element includes a second stop surface configured to cooperate with the first stop surface to limit travel of the control element within the sleeve; and a seal between the sleeve and the control element; wherein the control element includes a vent fluidly coupling a space between the sleeve and the control element with an interior of the control element. The space may extend between the seal and the first stop surface when the control element is in the first position. An elastomeric material may be positioned along the second stop surface. The resilient material may be an O-ring. The resilient material may prevent fluid flow between the first stop surface and the second stop surface when the control element is in the first position. The vent may extend radially through the check member between an inner surface of the check member in fluid communication with the inlet of the fluid control device portion and an outer surface of the check member positioned adjacent the sleeve. The vent may be positioned within the check member such that the vent is between the seal and the first stop surface when the check member is in the first position.

The fluid control device may be an axial flow device having a longitudinal axis. The first stop surface may be a first angled surface having an angle that is non-perpendicular to the longitudinal axis. The second stop surface is a second angled surface having an angle that is non-perpendicular to the longitudinal axis.

Disclosed is an emergency shutdown valve, comprising: a valve body defining an inlet, an outlet, and a fluid flow path between the inlet and the outlet; a sleeve positioned within the valve body, wherein the sleeve includes a first stop surface; a control element configured to slide within the sleeve between a first position in which the control element engages a valve seat to restrict fluid flow between the inlet and the outlet and a second position in which the control element is spaced from the valve seat to allow fluid flow between the inlet and the outlet, wherein the control element includes a second stop surface configured to cooperate with the first stop surface to limit travel of the control element within the sleeve; a spring biasing the control element toward the first position; an actuator assembly comprising a trigger mechanism, wherein the trigger mechanism is configured to prevent the control element from traveling to the first position in a first mode of operation and to enable the control element to travel to the first position in a second mode of operation, wherein the control element comprises a vent configured to prevent fluid from being trapped between the sleeve and the control element when the control element is in the first position. The actuator assembly may include a manual actuation assembly configured to allow manual movement of the control element from the first position to the second position.

Drawings

Fig. 1 is a cross-sectional side view of an axial flow slam shut valve assembled in accordance with the teachings of the present disclosure.

Fig. 2 is a cross-sectional side view of the mechanical stop portion of the axial flow slam shut valve of fig. 1 in accordance with the teachings of the present disclosure.

Fig. 3 is a cross-sectional side view of the mechanical stop portion of the axial flow slam shut valve of fig. 1 with a mechanical stop bleed system in accordance with the teachings of the present disclosure.

Detailed Description

FIG. 1 depicts an exemplary fluid control device 10 in which the mechanical stop drain system of the present disclosure may be implemented. The fluid control device 10 is an axial flow slam shut valve 10 that includes an actuator assembly 14. The axial flow slam shut valve 10 includes a valve body 18 and a valve assembly 22 disposed in the valve body 18. The valve body 18 defines an inlet 26, an outlet 30, and a fluid flow path 34 between the inlet 26 and the outlet 30. The valve body 18 has a longitudinal axis coaxially aligned with the longitudinal axis X of the valve stem 38. In contrast to the valve assembly 22, the flow path 34 is disposed toward the periphery of the valve body 18.

The valve assembly 22 includes a valve stem 38, a control element 42 coupled to a first end 44 of the valve stem 38, and a spring 46. The valve stem 38 and the control element 42 of the valve assembly 22 are movable along the longitudinal axis X between an open position, in which the control element 42 is spaced from the valve seat 50 to allow fluid flow through the valve 10 between the inlet 26 and the outlet 30, and a closed position, in which the control element 42 engages the valve seat 50 (shown in fig. 1) to restrict flow through the valve 10 between the inlet 26 and the outlet 30. The spring 46 biases the control element 42 toward a closed position in which the control element 42 engages the valve seat 50 to prevent fluid flow between the inlet 26 and the outlet 30.

The actuator assembly 14 includes a trigger mechanism 84, the trigger mechanism 84 being responsive to one or more process conditions (e.g., downstream pressure) and disposed outside of the valve body 18. The trigger mechanism 84 is operatively coupled to the drive shaft 72 of the actuator assembly 14. Drive shaft 72 is operatively coupled to scotch yoke mechanism 60, which scotch yoke mechanism 60 in turn is operatively coupled to valve stem 38. Rotation of the drive shaft 72 about the Y-axis results in linear movement of the valve stem 38 and control element 42 along the X-axis, and vice versa. In the first normal operating mode, the slam shut valve 10 is in the open position and the trigger mechanism 84 prevents the drive shaft 72 from rotating relative to the biasing force exerted by the spring 46 (via the scotch yoke mechanism 60). In this first mode of operation, the control element 42 is spaced from the valve seat 50, which enables fluid to flow from the inlet 26, through the openings in the cage 54 (which are available for fluid flow based on movement of the control element 42 in the direction K of the position shown in FIG. 1), along the fluid flow path 34, and out the outlet 30. In the first mode of operation, the trigger mechanism 84 is in a "standby" state such that any process shut-off condition (e.g., downstream pressure above or below a shut-off set point configured in the trigger mechanism, etc.) will cause the trigger mechanism 84 to immediately transition to the second mode of operation.

In the second mode of operation, trigger mechanism 84 is released, which allows drive shaft 72 to rotate (via scotch yoke mechanism 60) under the biasing force exerted by spring 46, thereby enabling control element 42 to be driven in the J direction by spring 46. In the closed position (shown in fig. 1) that occurs when the trigger mechanism 84 is in the second mode of operation, the control element 42 engages the valve seat 50, which prevents fluid flow between the inlet 26 and the outlet 30. The opening 62 in the control element 42 enables fluid at the inlet 26 to enter the control chamber 64 regardless of the position of the control element 42, which ensures that the fluid pressure at the inlet 26 is substantially equal to the fluid pressure in the control chamber 64. Thus, a force acting on control element 42 in direction K based on the fluid pressure at inlet 26 is offset by a substantially equal force acting on control element 42 in direction J based on the fluid pressure in control chamber 64.

When the trigger mechanism 84 trips to the second mode of operation, it must typically be switched back to the first mode of operation by: the emergency shut-off valve 10 is opened manually to move the control element 42 in the direction K until the triggering mechanism 84 is again armed to prevent rotation of the transmission shaft 72, thereby marking a return to the first operating mode. This manual actuation process is accomplished by a manual actuation assembly 86. Note that due to the above-described force balance provided by the equal fluid pressures at the inlet 26 and the control chamber 64, only the spring force need be overcome, and not the force created by the fluid pressure, when manually opening the valve and moving the control element 42.

The manual actuation assembly 86 includes the handle 64, the lever 76, and the transmission 68. A handle 64 (which may be a rotatable input device such as a knob, handwheel, etc.) is used to manually open the valve 10 and is connected to the drive mechanism 68 by a lever 76. The input shaft 80 (which may be part of the lever 76 or the transmission 68) is rotated about the axis Y by manual rotation of the handle 64 and the lever 76. The rotation of the input shaft 80 is transmitted to the transmission 68. More specifically, the lever 76 has a square bore that receives a square end of the input shaft 80 to couple the lever 76 to the transmission 68. The transmission 68 is configured to amplify the torque transmitted via the handle 64 into an output torque that is transmitted to the transmission shaft 72. Drive train 68 is coupled to drive shaft 72 and transmits an output torque to shaft 72, which shaft 72 in turn transmits the output torque to move control element 42 through scotch yoke mechanism 60. The scotch yoke mechanism 60 is connected to the second end 56 of the valve stem 38 of the slam shut valve 10 and converts the rotational movement of the shaft 72 into linear movement of the valve stem 38 to open (i.e., reset) the valve 10.

As shown in fig. 2, the control element 42 slides within the sleeve 8 positioned within the valve body 18. The seal 36 prevents fluid from flowing between the sleeve 8 and the control element 42, which would otherwise form a flow path between the control chamber 64 and the fluid flow path 34. When the trigger mechanism 84 trips and transitions to the second mode of operation, the spring 46 drives the control element 42 in the direction J with a significant force and speed. A mechanical stop (shown in fig. 2) limits the travel of the control element 42 so that the control element properly engages the valve seat 50 without damaging the sealing surfaces of the control element 42 and the valve seat 50. The mechanical stop is provided by interference between an inwardly angled first stop face 12 of the sleeve 8 and an outwardly angled second stop face 24 of the control element 42, the first and second stop faces 12, 24 cooperating to allow the control element 42 to travel only in the direction J until the face 24 contacts the face 12, at which time the sealing surface of the control element 42 engages the sealing surface of the valve seat 50. To reduce the impact of the collision between

surfaces

12 and 24, a cushion O-ring 16 is positioned between control element 42 and a ring 20 coupled to a downstream end of control element 42 (i.e., along surface 24). The cushion O-ring 16 is formed of an elastomeric material and is positioned to contact the surface 12 before the surface 24 contacts the surface 12 to reduce the impact of the collision between the

surfaces

12 and 24. Although the purpose of the cushion O-ring 16 is not to provide a seal between the control element 42 and the sleeve 8, it does form such a seal when the control element 42 is in the closed position (i.e., when the cushion O-ring contacts the surface 12) due to the deformable nature of the cushion O-ring.

While such unintended sealing by the cushion O-ring 16 may be expected to function as a harmless redundancy to the seal 36 when the emergency shutdown valve 10 is in the closed position, the inventors have discovered unintended results. Specifically, the seal created by the contact between the cushion O-ring 16 and the surface 12 results in a sealed space 32 between the seal 36 and the cushion O-ring 16 when the control element 42 is in the closed position (i.e., the cushion O-ring 16 prevents fluid flow between the sleeve 8 and the control element 42 when the control element 42 is in the closed position). As should be appreciated, when the control element 42 is in the open position, the control element 42, the ring 20, and the cushion O-ring 16 all move in the direction K from the position shown in fig. 2. In this open position, the cushion O-ring 16 is spaced from the surface 12, which allows fluid from the control chamber 64 to enter the gap between the control element 42 and the sleeve 8 to the point of the seal 36. As described above, control chamber 64 is in fluid communication with inlet 26, and thus the fluid pressure within control chamber 64 and within the space between control element 42 and sleeve 8 is substantially equal to the fluid pressure at inlet 26. When the triggering mechanism 84 is switched to the second operating mode and the control element 42 is moved in the direction J until the damping O-ring 16 contacts the surface 12, the fluid trapped in the sealing space 32 has a pressure P2, which pressure P2 is equal to the fluid pressure at the inlet 26 and inside the control chamber 64 when the slam shut valve 10 is closed. When the slam shut valve 10 is closed, the fluid pressure generally at the inlet 26, and therefore the fluid pressure in the control chamber 64, rises to a pressure P1 that exceeds the pressure P2. Thus, the force acting on control element 42 in direction K due to fluid pressure P2 over region a is less than the force acting on control element 42 in direction J due to fluid pressure P1 over region a. Although the cross-sectional area a appears small, the area a forms an annular zone that follows the circumference of the surface 24. When the emergency shutdown valve 10 has a large size (e.g., 12 inches), the annular region corresponding to region a may have a significant area. For example, the annular region may have an area of about 8-10 square inches. Also, the difference between fluid pressures P1 and P2 may be large. For example, the difference between P1 and P2 can reach a level of about 150 psi. Thus, the imbalance forces generated by the fluid pressure differential between P1 and P2 acting on the annular zone corresponding to zone a may be significant (e.g., up to 1,200 to 1,500 pounds). As described above, the control element 42 must be manually moved in the direction K to reestablish flow through the slam shut valve 10 and to re-arm the triggering mechanism 84 by placing the triggering mechanism 84 in the first mode of operation. The unbalanced forces caused by the pressure difference between P1 and P2 may make this manual operation difficult or impossible.

To address this problem, the inventors have devised a technique to eliminate the pressure differential and thus the resulting imbalance forces. Specifically, as shown in FIG. 3, the check member 42 is formed with a vent 46, the vent 46 extending radially through the check member 42. Vent 46 is positioned in check member 42 slightly in the J direction from cushion O-ring 16 such that vent 46 fluidly couples chamber 32 with check chamber 64 (i.e., with the interior of check member 42) when check member 42 is in the closed position. In one embodiment, there may be a single vent 46 along the inner circumference of the check member 42. In another embodiment, there may be a plurality of vents 46 spaced along the inner circumference of the check member 42. The fluid coupling between the chamber 32 and the control chamber 64 ensures pressure equalization and thereby eliminates unbalanced forces that may make it difficult or impossible to manually reset the emergency shutdown valve 10.

The drawings and description provided herein depict and describe preferred embodiments of an axial adjuster for purposes of illustration only. One skilled in the art will readily recognize from the foregoing discussion that alternative embodiments of the components illustrated herein may be employed without departing from the principles described herein. Accordingly, other alternative structural and functional designs of the axial adjuster will be understood by those skilled in the art upon reading this disclosure. Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the disclosed embodiments are not limited to the precise construction and components disclosed herein. Various modifications, changes, and variations apparent to those skilled in the art may be made in the arrangement, operation, and details of the methods and components disclosed herein without departing from the spirit and scope defined in the appended claims.

Claims

1. A fluid control device, comprising:

a sleeve including a first stop surface;

a control element configured to slide within the sleeve between a first position in which the control element engages a valve seat to restrict fluid flow through the fluid control device and a second position in which the control element is spaced from the valve seat to allow fluid flow through the fluid control device, wherein the control element includes a second stop surface configured to cooperate with the first stop surface to limit travel of the control element within the sleeve; and

a seal between the sleeve and the control element, wherein the control element includes a vent fluidly coupling a space between the sleeve and the control element with an interior of the control element.

2. The fluid control device of claim 1, wherein the space extends between the seal and the first stop surface when the control element is in the first position.

3. The fluid control device of claim 1, wherein an elastomeric material is positioned along the second stop surface.

4. The fluid control device of claim 3, wherein the resilient material comprises an O-ring.

5. The fluid control device of claim 4, wherein the resilient material prevents fluid flow between the first and second stop surfaces when the control element is in the first position.

6. The fluid control device of claim 1, wherein the vent extends radially through the check member between an inner surface of the check member in fluid communication with the inlet of the fluid control device and an outer surface of the check member positioned adjacent the sleeve.

7. The fluid control device of claim 6, wherein the vent is positioned along the check element at a location that positions the vent between the seal and the first stop surface when the check element is in the first position.

8. The fluid control device of claim 1, wherein the fluid control device is an axial flow device having a longitudinal axis.

9. The fluid control device of claim 8, wherein the first stop surface is a first angled surface having an angle that is non-perpendicular to the longitudinal axis.

10. The fluid control device of claim 9, wherein the second stop surface is a second angled surface having an angle that is non-perpendicular to the longitudinal axis.

11. An emergency shutdown valve comprising:

a valve body defining an inlet, an outlet, and a fluid flow path between the inlet and the outlet;

a sleeve positioned within the valve body, wherein the sleeve includes a first stop surface;

a control element configured to slide within the sleeve between a first position in which the control element engages a valve seat to restrict fluid flow between the inlet and the outlet and a second position in which the control element is spaced from the valve seat to allow fluid flow between the inlet and the outlet, wherein the control element includes a second stop surface configured to cooperate with the first stop surface to limit travel of the control element within the sleeve;

a spring biasing the control element toward the first position; and

an actuator assembly comprising a trigger mechanism, wherein the trigger mechanism is configured to prevent the control element from traveling to the first position in a first mode of operation and to enable the control element to travel to the first position in a second mode of operation, wherein the control element comprises a vent configured to prevent fluid from being trapped between the sleeve and the control element when the control element is in the first position.

12. The emergency shutdown valve of claim 11, wherein the actuator assembly comprises a manual actuation assembly configured to allow the control element to be manually moved from the first position to the second position.