Slam Shut Valve Guide Collar Reset Pin Protection
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Solution Overview
Problem
Conventional slam-shut safety valves in gas distribution systems face operational issues due to fluid forces deforming or bending the reset pin, affecting the proper functioning of the safety device, especially under high flow conditions.
Innovation Solution
The design incorporates a guide collar and plug support that shiftable along the slam-shut axis, providing structural integrity by transferring fluid forces away from the reset pin, and includes longitudinal guide ribs and channels for venting, ensuring the reset pin remains stable and functional.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the reset pin is exposed to fluid flow in conventional slam-shut devices, then the device structure is simple, but the reset pin deforms or bends under high flow conditions, affecting proper operation
Solution Approach 1:
The guide collar serves as an intermediary component between the reset pin and the fluid flow. It shields the reset pin from direct exposure to high-velocity fluid forces while allowing the reset pin to perform its resetting function. The guide collar transfers fluid forces to the valve body through friction and contact, protecting the reset pin from deformation.
Solution Approach 2:
The harmful effect of fluid forces on the reset pin is extracted and isolated by introducing the guide collar. The guide collar captures and redirects the fluid forces away from the reset pin, allowing the reset pin to operate without being subjected to deforming forces from high-velocity flow.
2Reliability
If the guide collar is added to protect the reset pin, then the reset pin stability is improved, but the device complexity increases
Solution Approach 1:
The guide collar performs multiple functions simultaneously: it guides the reset pin during operation, shields the reset pin from fluid forces, provides structural support, and facilitates venting of trapped fluid through longitudinal channels. This multi-functionality justifies the additional component by consolidating several protective and operational roles into a single element.
Solution Approach 2:
The guide collar is positioned within the valve body structure, nesting the protective function within the existing device architecture. The longitudinal guide ribs are integrated into the guide collar itself, creating a nested structure where guiding and venting functions are combined in a space-efficient manner.
3Strength
If longitudinal guide ribs are added to the guide collar, then the structural integrity is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The guide ribs change the geometric parameters of the guide collar, adding structural reinforcement features that increase stiffness and strength. These ribs modify the moment of inertia and structural rigidity of the guide collar, enabling it to better resist fluid forces without requiring a complete redesign of the entire component.
Solution Approach 2:
The guide collar structure is segmented into regions with and without guide ribs, creating localized reinforcement zones. This segmentation allows the structure to be stronger where needed (where fluid forces are highest) while maintaining simplicity in other areas, optimizing the strength-to-manufacturing-complexity ratio.
Data Source
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AI summary
A slam-shut safety device includes a valve body (112), a valve disc (122), a reset pin (160), a and a guide collar (162). The valve disc (122) is shiftable between an open position spaced away from a valve seat (120), and a closed position seated against the valve seat (120). The reset pin (160) operatively is coupled to the valve disc (122) and shiftable between an untripped position placing the valve disc (122) in the open position and a tripped position placing the valve disc (122) in the closed position. The guide collar (162) includes a hollow cylindrical portion slidably supported in a guide bore and extending at least partly over the reset pin 160) at a location adjacent to the valve disc (122). The guide collar (162) is shiftable between a retracted position and an extended position relative to the guide bore for providing added structural integrity and protecting the reset pin from bending forces.