Split Coupling Connects Valve Stem to Ceramic Member

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Solution Overview

Problem

Connecting a metal valve stem to a non-metallic valve member, such as ceramic, poses challenges due to incompatibility with welding and can result in damage to the ceramic member from tensile forces exerted by the metal stem's threads, and existing solutions like drive pins can cause misalignment.

Innovation Solution

A split coupling with a resilient member and washer is used to securely connect the valve stem to the valve member, distributing forces and allowing for self-adjustment and alignment, while preventing fluid ingress and accommodating various environmental conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal valve stem is connected to a non-metallic valve member using threads, then the connection is secure, but the tensile forces exerted by the metal stem's threads can damage the ceramic valve member

Engineering Contradiction:

Improveconnection strengthVSAvoiddamage to ceramic valve member

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

A drive sleeve is introduced as an intermediary component between the metal valve stem and the ceramic valve member. The drive sleeve receives tensile forces from the metal stem and transmits them to the ceramic member through bearing surfaces, preventing direct thread engagement and avoiding damage to the ceramic material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The direct threaded mechanical connection between metal stem and ceramic member is replaced with a bearing surface-based force transmission system. The drive sleeve provides a smooth bearing surface that distributes tensile forces, substituting the damaging thread-to-ceramic contact with a more suitable force transmission mechanism.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If a drive pin is used to connect the valve stem to the valve member, then the connection is secure, but misalignment between the valve stem and valve member occurs

Engineering Contradiction:

Improveconnection strengthVSAvoidalignment precision

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The connection system is segmented into three distinct components: the valve stem, the drive sleeve, and the valve member. This segmentation allows each component to be optimized independently and facilitates easier alignment during assembly, as the drive sleeve can accommodate minor misalignments between the stem and member.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The drive sleeve serves as a mediator that facilitates alignment between the valve stem and valve member. It provides a interface that can accommodate dimensional tolerances and ensure proper alignment during assembly, preventing the misalignment issues associated with direct drive pin connections.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If welding is used to connect the valve stem to the valve member, then the connection is strong, but the filler material may be incompatible with the base material of the valve stem or valve plug

Engineering Contradiction:

Improveconnection strengthVSAvoidmaterial compatibility

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The welding process is replaced with a mechanical connection system using the drive sleeve. This substitution eliminates the material compatibility issues inherent in welding dissimilar materials, as the mechanical connection does not require filler materials and can join metal and non-metal components without chemical reactions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution ensures reliable operation under harsh conditions, including high vibration, temperature, and pressure, by securely connecting the valve stem to the valve member without damage, maintaining fluid integrity and preventing misalignment.

Implementation Method 1

A split coupling with a resilient member and washer is used to securely connect the valve stem to the valve member, distributing forces

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP2191177B1Apparatus to connect a valve stem to a valve member

Publication Date: 2019.07.10 FISHER CONTROLS INT LLC

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AI summary

Apparatus to connect a valve stem (20) to a valve member (40) are disclosed. An example apparatus includes a valve stem having a laterally extending opening, a valve member having a laterally extending opening, and a coupling (70) having adjacent one end an extension received in the laterally extending opening of the valve stem and adjacent an opposite end an extension received in the laterally extending opening of the valve member. A resilient member (30) is located between the valve stem and the valve member.