Slam Shut Valve Guided Relatch Plug and Disc Guide

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Solution Overview

Problem

Existing slam-shut safety valves in gas distribution systems face issues with latching plug binding under high pressure loads, clip failure at high flow velocities, and misalignment of safety discs, leading to incomplete sealing and unreliable shutoffs.

Innovation Solution

The design incorporates co-axially located overpressure and underpressure springs with independent adjustment capabilities, a guided relatch plug to prevent binding, and a coupling nut to resist high kinetic forces, along with a disc guide for precise alignment of the safety disc, ensuring reliable sealing and shutoff.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a reset rod guides the latching plug in known slam-shut safety valves, then the valve structure is simple, but the reset rod binds under high pressure loads from a latching cam

Engineering Contradiction:
Improvevalve structureVSAvoidlatching plug operation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

A guided slot in the valve body serves as an intermediary constraint system. Instead of a simple reset rod guiding the latching plug, the guided slot provides lateral guidance and constraint, preventing binding while allowing axial movement. The slot acts as a mediator between the latching plug and the valve body, ensuring reliable operation under high pressure loads.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If clips attach the latching plugs to the reset rod in known slam-shut safety valves, then the assembly is simple, but the clips fail under high kinetic forces from high flow velocity valves

Engineering Contradiction:
Improveattachment mechanismVSAvoidclip resistance to kinetic forces
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The latching plug is integrally formed with the reset rod as a single monolithic component. This merging eliminates the separate clips that failed under kinetic forces, combining the attachment function into the basic structure itself. The integral design ensures that high kinetic forces from high flow velocity valves are transmitted directly through the solid structure without relying on separate attachment elements.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If safety discs in known slam-shut safety devices operate without guidance, then the structure is simple, but the safety discs misalign under high flow velocities causing incomplete sealing

Engineering Contradiction:
Improvedisc mounting structureVSAvoidsafety disc alignment
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

A disc guide structure acts as an intermediary alignment mechanism. The disc guide provides lateral guidance and constraint for the safety disc, ensuring proper alignment with the valve seat even under high flow velocities. This guided structure mediates between the disc mounting and the sealing surface, preventing misalignment and ensuring complete sealing.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Adaptability or versatility

If overpressure and underpressure springs are separately adjusted in known slam-shut safety valves, then pressure control flexibility is improved, but device complexity increases

Engineering Contradiction:
Improvepressure control flexibilityVSAvoidspring adjustment mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The overpressure and underpressure springs are positioned co-axially and adjusted through a single unified adjustment mechanism. This merging of the adjustment functions allows both springs to be controlled from one location, maintaining pressure control flexibility while reducing device complexity. The single adjustment mechanism coordinates both spring pressures simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances the reliability and durability of slam-shut safety valves by preventing binding and misalignment, ensuring consistent and effective gas flow regulation across varying pressure conditions.

Implementation Method 1

The slam shut safety device includes an overpressure spring and an underpressure spring disposed within the upper case in a co-axial configuration

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The overpressure spring determines the upper acceptable gas pressure and the underpressure spring determines the lower acceptable gas pressure

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3201502B1Slam shut safety device
Publication Date: 2019.12.04 EMERSON PROCESS MANAGEMENT REGULATOR TECHNOLOGIES INC
  • EP3201502B1 patent drawingFigure 1
  • EP3201502B1 patent drawingFigure 2~3
  • EP3201502B1 patent drawingFigure 4

AI summary

A safety device for a gas distribution system includes a valve body (12), an upper casing (14) attached to the valve body, the upper casing housing at least one spring (30,32). Further, the at least one spring is attached to a movable diaphragm (42) that is exposed to gas system pressure. The valve body also includes a release element (62) mounted within the valve body. The release element releasing a relatch plug (70) when the device is activated to move a safety disc (16) into contact with a valve seat to stop fluid from flowing when an overpressure or an underpressure condition is sensed.