Control Valve Positioner Mounting With Spring-Loaded Bushings

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Solution Overview

Problem

Existing control valve positioner mounting kits introduce additional forces to the valve stem system and cause material erosion due to constant movement, leading to inaccuracies in position measurement.

Innovation Solution

A closed spring force circuit is applied to an attachment arm using a pair of bushings with a spring-loaded attachment system, where the spring force is anchored to minimize transference to the control valve stem and maintain consistent attachment despite wear, using materials like Teflon for low friction and electrical neutrality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring is used to maintain the lever on the control valve stem, then the lever is kept in contact with the stem, but spring force is transferred to the valve stem system causing measurement inaccuracies

Engineering Contradiction:

Improvelever contact maintenanceVSAvoidposition measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system divides the force application into separate pathways: the spring force is applied to the lever through the bushing assembly, while the lever's movement is transmitted to the positioner through a separate feedback arm connection. This segmentation prevents spring force from being transferred to the valve stem while maintaining lever contact.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A bushing assembly acts as an intermediary between the spring and the lever. The bushing receives spring force and transfers only positional information to the lever through friction contact, while allowing the lever to move independently without spring force interference to the positioner measurement system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a spring-loaded attachment is used to maintain lever contact, then the lever remains attached to the stem, but material erosion occurs at the connection point due to constant movement

Engineering Contradiction:

Improveattachment stabilityVSAvoidmaterial erosion at connection point

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The bushing assembly serves as a sacrificial intermediary that absorbs wear from constant movement. The bushing material (such as Teflon) is selected to be softer than the lever and stem materials, so erosion occurs in the bushing rather than in the critical lever-stem connection points, maintaining attachment stability while minimizing material loss from vital components.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the material parameters of the bushing to have low friction and high wear resistance properties. By selecting materials with appropriate friction coefficients and wear characteristics, the system reduces both the erosive effects and the spring force transfer to the valve stem.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If a lever with rotating connection is used to translate linear valve stem movement to rotating positioner movement, then the positioner can measure valve stroke, but friction and differential pressures affect the valve position

Engineering Contradiction:

Improvevalve stroke measurementVSAvoidfriction and differential pressure influence

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system replaces the direct mechanical rotating connection with a friction-based sliding contact system. The bushing allows the lever to slide against it with minimal friction, converting the mechanical rotation requirement into a simpler sliding motion that is less sensitive to friction and differential pressure effects, while still enabling the feedback arm to translate the movement to the positioner.

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 minimizes the transfer of spring force to the control valve stem, reduces material erosion, and maintains consistent attachment force, ensuring precise position measurement and reduced wear over time.

Implementation Method 1

a control valve attachment system for attaching the control valve to the attachment lever using a spring loaded attachment affixed to the control valve and applying spring force to the attachment lever

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 2

using materials like Teflon for low friction and electrical neutrality

Methodology Applied

Scientific EffectFriction reduction: Lubrication

Data Source

PatentUS9772046B2Method and apparatus for mounting a control valve positioner

Publication Date: 2017.09.26 BADGER METER INC

AI summary

A control valve positioner mounting system is configured to include a control valve, a control valve positioner, an attachment lever translating movement of the control valve to the control valve positioner, and a control valve attachment system for attaching the control valve to the attachment lever using a spring loaded attachment affixed to the control valve and applying spring force to the attachment lever.