Mechanical stop bleed for fluid control equipment

Abstract

Mechanical stop bleed 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 element within the sleeve is limited by interfering stop surfaces of the sleeve and the control element, thereby preventing the control element stop surface from sliding beyond the sleeve stop surface. A bleed port fluidly couples the space existing between the sleeve and the control element with the interior of the control element.

Description

Technical Field

[0001] The present invention relates to a fluid control device, and in particular to a mechanical stop-and-discharge system for the fluid control device. Background Art

[0002] Emergency shut-off valves are valves that are quickly actuated (e.g., can be quickly closed in an emergency) in the event of a detected process condition. Typically, emergency shut-off valves include a valve and an emergency shut-off trigger mechanism that can drive a control element to quickly shut off the flow path of the valve when the process condition reaches a fixed set point. When certain fixed set points are met, the emergency shut-off valve shuts off the flow to protect downstream components in the system. When the system returns to normal operation, a manual reset of the shut-off is required to open the valve. Summary of the invention

[0003] A fluid control device is disclosed, comprising: a sleeve, the sleeve comprising a first stop surface; a control element, the control element being configured to slide within the sleeve between a first position and a second position, in which the control element engages a valve seat to restrict fluid flow through the fluid control device, and in which the control element is spaced apart from the valve seat to allow fluid flow through the fluid control device, wherein the control element comprises a second stop surface, the second stop surface being configured to cooperate with the first stop surface to limit the travel of the control element within the sleeve; and a seal located between the sleeve and the control element; wherein the control element comprises a vent, the vent fluidically coupling a space between the sleeve and the control element with an interior of the control element. When the control element is in the first position, the space may extend between the seal and the first stop surface. An elastic material may be positioned along the second stop surface. The elastic material may be an O-ring. When the control element is in the first position, the elastic material may prevent fluid flow between the first stop surface and the second stop surface. The vent may extend radially through the control element between an inner surface of the control element in fluid communication with an inlet of the fluid control device portion and an outer surface of the control element positioned adjacent the sleeve. The vent may be positioned within the control element such that when the control element is in the first position, the vent is located between the seal and the first stop surface.

[0004] 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 not perpendicular to the longitudinal axis. The second stop surface may be a second angled surface having an angle that is not perpendicular to the longitudinal axis.

[0005] An emergency shutoff valve is disclosed, comprising: a valve body, the valve body defining an inlet, an outlet, and a fluid flow path between the inlet and the outlet; a sleeve, the sleeve being positioned within the valve body, wherein the sleeve comprises a first stop surface; a control element, the control element being configured to slide within the sleeve between a first position and a second position, wherein in the first position, the control element engages a valve seat to restrict fluid flow between the inlet and the outlet, and in the second position, the control element is spaced apart from the valve seat to allow fluid flow between the inlet and the outlet, wherein the control element comprises a second stop surface, The second stop surface is configured to cooperate with the first stop surface to limit the travel of the control element within the sleeve; a spring that biases the control element toward the first position; and an actuator assembly that includes a trigger mechanism, wherein the trigger mechanism is configured to prevent the control element from traveling to the first position in a first operating mode and enable the control element to travel to the first position in a second operating mode, wherein the control element includes a vent that is 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 that is configured to allow the control element to be manually moved from the first position to the second position. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a cross-sectional side view of an axial flow emergency shutdown valve assembled according to the teachings of the present disclosure.

[0007] Figure 2 According to the teachings of this disclosure, Figure 1 A sectional side view of the mechanical stop portion of an axial flow emergency shut-off valve.

[0008] Figure 3 A mechanical stop-discharge system according to the teachings of the present disclosure Figure 1 A sectional side view of the mechanical stop portion of an axial flow emergency shut-off valve. DETAILED DESCRIPTION

[0009] Figure 1An exemplary fluid control device 10 in which a mechanical stop and bleed system of the present disclosure may be implemented is depicted. The fluid control device 10 is an axial flow emergency shutoff valve 10 that includes an actuator assembly 14. The axial flow emergency shutoff 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 that is coaxially aligned with a longitudinal axis X of a valve stem 38. Compared to the valve assembly 22, the flow path 34 is arranged toward the periphery of the valve body 18.

[0010] 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 and a closed position, in which the control element 42 is spaced apart from the valve seat 50 to allow fluid flow through the valve 10 between the inlet 26 and the outlet 30, and in which the control element 42 engages the valve seat 50 (e.g., Figure 1 4 (shown) to restrict flow through the valve 10 between the inlet 26 and the outlet 30. The spring 46 biases the control element 42 toward the 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.

[0011] The actuator assembly 14 includes a trigger mechanism 84 that is responsive to one or more process conditions (e.g., downstream pressure) and is disposed outside of the valve body 18. The trigger mechanism 84 is operably coupled to the drive shaft 72 of the actuator assembly 14. The drive shaft 72 is operably coupled to the scotch yoke mechanism 60, which in turn is operably coupled to the valve stem 38. Rotation of the drive shaft 72 about the Y axis causes linear movement of the valve stem 38 and the control element 42 along the X axis, and vice versa. In a first normal operating mode, the slam shut valve 10 is in an open position, and the trigger mechanism 84 prevents the drive shaft 72 from rotating relative to the biasing force applied by the spring 46 (via the scotch yoke mechanism 60). In this first operating mode, the control element 42 is spaced apart from the valve seat 50, which enables fluid to flow from the inlet 26 through the openings in the cage 54 (which openings are based on the control element 42 in the first operating mode). Figure 1 The trigger mechanism 84 is in a "standby" state so that any process shutoff condition (e.g., downstream pressure is above or below a shutoff set point configured in the trigger mechanism, etc.) will immediately switch the trigger mechanism 84 to the second operating mode.

[0012] In the second operating mode, the trigger mechanism 84 is released, which allows the drive shaft 72 to rotate under the biasing force applied by the spring 46 (via the scotch yoke mechanism 60), thereby enabling the control element 42 to be driven in the J direction by the spring 46. The closed position (eg, Figure 1 4 ), the control element 42 engages the valve seat 50, which prevents fluid from flowing between the inlet 26 and the outlet 30. The opening 62 in the control element 42 enables the 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. Therefore, the force acting on the control element 42 in the direction K based on the fluid pressure at the inlet 26 is offset by the substantially equal force acting on the control element 42 in the direction J based on the fluid pressure in the control chamber 64.

[0013] When the trigger mechanism 84 trips to the second operating mode, it is usually necessary to switch back to the first operating mode by manually opening the emergency shut-off valve 10 to move the control element 42 in the direction K until the trigger mechanism 84 is again armed to prevent rotation of the drive shaft 72, thereby marking a return to the first operating mode. This manual actuation process is achieved by the manual actuation assembly 86. Note that due to the above-mentioned force balance provided by the equal fluid pressures at the inlet 26 and the control chamber 64, when manually opening the valve and moving the control element 42, only the spring force needs to be overcome, and no force generated by the fluid pressure needs to be overcome.

[0014] The manual actuation assembly 86 includes a handle 66, a lever 76, and a transmission mechanism 68. The handle 66 (which may be a rotatable input device such as a knob, a hand wheel, etc.) is used to manually open the valve 10 and is connected to the transmission mechanism 68 through the lever 76. The input shaft 80 (which may be a part of the lever 76 or the transmission mechanism 68) is rotated about the axis Y by manual rotation of the handle 66 and the lever 76. The rotation of the input shaft 80 is transmitted to the transmission mechanism 68. More specifically, the lever 76 has a square hole that receives the square end of the input shaft 80 to couple the lever 76 to the transmission mechanism 68. The transmission mechanism 68 is configured to amplify the torque transmitted via the handle 66 into an output torque that is transmitted to the transmission shaft 72. The transmission mechanism 68 is coupled to the transmission shaft 72 and transmits the output torque to the shaft 72, which in turn transmits the output torque to move the control element 42 through the 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 motion of the shaft 72 into linear motion of the valve stem 38 to open (ie, reset) the valve 10 .

[0015] like Figure 2As shown, 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 is tripped and switched to the second operating mode, the spring 46 drives the control element 42 in the direction J with significant force and speed. Mechanical stop ( Figure 2 5 (shown in FIG. 5 ) 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 the inwardly angled first stop surface 12 of the sleeve 8 and the outwardly angled second stop surface 24 of the control element 42, which cooperate to allow the control element 42 to travel only in the direction J until the second stop surface 24 contacts the first stop surface 12, at which time the sealing surface of the control element 42 engages the sealing surface of the valve seat 50. To reduce the effects of the collision between the first stop surface 12 and the second stop surface 24, a buffer O-ring 16 is positioned between the control element 42 and the ring 20 coupled to the downstream end of the control element 42 (i.e., along the second stop surface 24). The buffer O-ring 16 is formed of an elastomeric material and is positioned to contact the first stop surface 12 before the second stop surface 24 contacts the first stop surface 12 to reduce the effects of collision between the first stop surface 12 and the second stop surface 24. Although the purpose of the buffer O-ring 16 is not to provide a seal between the control element 42 and the sleeve 8, due to the deformable nature of the buffer O-ring, it does form such a seal when the control element 42 is in the closed position (i.e., when the buffer O-ring contacts the first stop surface 12).

[0016] Although it may be expected that this unintended seal created by the buffer O-ring 16 would function as a harmless redundancy to the seal 36 when the emergency shut-off valve 10 is in the closed position, the inventors have discovered an unintended result. Specifically, when the control element 42 is in the closed position, the seal created by the contact between the buffer O-ring 16 and the first stop surface 12 results in a sealed space 32 between the seal 36 and the buffer O-ring 16 (i.e., when the control element 42 is in the closed position, the buffer O-ring 16 blocks fluid flow between the sleeve 8 and the control element 42). As should be appreciated, when the control element 42 is in the open position, the control element 42, the ring 20, and the buffer O-ring 16 are all blocked from the seal 36 and the first stop surface 12. Figure 2The position shown moves in the direction K. In this open position, the buffer O-ring 16 is spaced from the first stop surface 12, which allows fluid from the control chamber 64 to enter the gap between the control element 42 and the sleeve 8 up to the point of the seal 36. As described above, the control chamber 64 is in fluid communication with the inlet 26, so the fluid pressure within the control chamber 64 and the fluid pressure in the gap between the control element 42 and the sleeve 8 is substantially equal to the fluid pressure at the inlet 26. When the trigger mechanism 84 is switched to the second operating mode and the control element 42 is moved in the direction J until the buffer O-ring 16 contacts the first stop surface 12, the fluid trapped in the sealed space 32 has a pressure P2 that is equal to the fluid pressure at the inlet 26 and inside the control chamber 64 when the emergency shutdown valve 10 is closed. When the emergency shutdown valve 10 is closed, the fluid pressure at the inlet 26 and therefore the fluid pressure in the control chamber 64 generally rises to a pressure P1 that exceeds the pressure P2. Therefore, the force acting on the control element 42 in the direction K due to the fluid pressure P2 on the area A is less than the force acting on the control element 42 in the direction J due to the fluid pressure P1 on the area A. Although the cross-sectional area A appears small, the area A forms an annular area that follows the circumference of the surface 24. When the emergency shut-off valve 10 has a large size (e.g., 12 inches), the annular area corresponding to the area A can have a significant area. For example, the annular area can have an area of ​​about 8-10 square inches. Moreover, the difference between the fluid pressures P1 and P2 can be large. For example, the difference between P1 and P2 can reach a level of about 150 psi. Therefore, the unbalanced force generated by the fluid pressure difference between P1 and P2 acting on the annular area corresponding to the area A can 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 the flow through the emergency shut-off valve 10 and to re-arm the trigger mechanism 84 by placing the trigger mechanism 84 in the first operating mode. The unbalanced forces caused by the pressure differential between P1 and P2 may make this manual operation difficult or impossible.

[0017] In order to solve this problem, the inventors have designed a technology to eliminate the pressure difference and thus eliminate the unbalanced force generated. Figure 3As shown, the control element 42 is formed with a vent 46 that extends radially through the control element 42. The vent 46 is positioned in the control element 42 slightly in the J direction from the buffer O-ring 16 so that when the control element 42 is in the closed position, the vent 46 fluidly couples the sealed space 32 with the control chamber 64 (i.e., with the interior of the control element 42). In one embodiment, there may be a single vent 46 along the inner circumference of the control element 42. In another embodiment, there may be a plurality of vents 46 spaced apart along the inner circumference of the control element 42. The fluid coupling between the sealed space 32 and the control chamber 64 ensures pressure equalization and thereby eliminates unbalanced forces that would make it difficult or impossible to manually reset the emergency shutoff valve 10.

[0018] The drawings and descriptions provided herein depict and describe preferred embodiments of the axial adjuster for illustrative purposes only. Those skilled in the art will readily recognize from the foregoing discussion that alternative embodiments of the components shown herein may be adopted without departing from the principles described herein. Therefore, after reading the present disclosure, those skilled in the art will understand other alternative structural and functional designs of the axial adjuster. Therefore, although specific embodiments and applications have been illustrated and described, it should be understood that the disclosed embodiments are not limited to the precise constructions and components disclosed herein. Various modifications, changes and variations that are obvious to those skilled in the art may be made to 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, the sleeve comprising 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 apart 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 is positioned between the sleeve and the control element, wherein the control element includes a vent that fluidly couples a space between the sleeve and the control element with an interior of the control element.

2. The fluid control device according to claim 1, wherein: When the control element is in the first position, the space extends between the seal and the first stop surface.

3. The fluid control device according to claim 1, wherein: A resilient material is positioned along the second stop surface.

4. The fluid control device according to claim 3, wherein: The elastic material includes an O-ring.

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

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

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

8. The fluid control device according to claim 1, wherein: The fluid control device is an axial flow device having a longitudinal axis.

9. The fluid control device according to 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 according to 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 shut-off 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 apart 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 operating mode and to enable the control element to travel to the first position in a second operating mode, 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 shut-off valve according to claim 11, wherein: The actuator assembly includes a manual actuation assembly configured to allow manual movement of the control element from the first position to the second position.

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