Integrated Valve Shaft Bushing Seal for Short-Shaft Leak Control

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Solution Overview

Problem

Fluid valves with short shafts face issues due to inadequate support and increased torque requirements when relying solely on packing for support, leading to potential leaks and reduced lifespan, as they cannot accommodate both bushing and packing simultaneously without compromising either support or sealing.

Innovation Solution

A bushing with an integral seal is used to support and seal the valve shaft, eliminating the need for a separate packing and reducing the overall size of the valve, while providing enhanced support and leak protection by integrating the seal directly into the bushing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate packing and bushing are used to support and seal the valve shaft, then sealing reliability is improved, but device complexity and shaft length requirements increase

Engineering Contradiction:
Improvesealing reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the packing and bushing into a single integrated bushing component with an integral seal. The seal is directly formed as part of the bushing structure, eliminating the need for a separate packing component. This merging reduces the number of parts while maintaining both support and sealing functions, thereby improving reliability without increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated bushing performs multiple functions simultaneously: it provides shaft support, guides shaft movement, and seals against fluid leaks through its integral seal. This multi-functional design eliminates the need for separate dedicated components for each function, reducing overall device complexity while maintaining comprehensive performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Force

If packing is used to support the shaft, then shaft support is provided, but torque requirements increase and packing lifespan decreases

Engineering Contradiction:
Improveshaft supportVSAvoidtorque requirements
Core Design Contradiction:
ForceVSPower

Solution Approach 1:

By merging the support function and sealing function into a single integrated bushing structure, the design eliminates the need for soft packing material to bear shaft support loads. The rigid bushing structure provides mechanical support while the integral seal handles sealing, reducing torque requirements compared to using packing alone for support.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If bushing and packing are both accommodated, then shaft support and sealing are both provided, but shaft length must be increased

Engineering Contradiction:
Improveshaft support and sealingVSAvoidshaft length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent merges the bushing and packing into a single integrated component, allowing both support and sealing functions to be provided within a compact space. The integral seal is formed as part of the bushing structure, eliminating the need for additional shaft length to accommodate separate components, thus maintaining reliability without increasing shaft length.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3717813B1Bushing having a shaft seal
Publication Date: 2022.03.23 FISHER CONTROLS INT LLC
  • EP3717813B1 patent drawingFigure 1
  • EP3717813B1 patent drawingFigure 2
  • EP3717813B1 patent drawingFigure 3A~3D

AI summary

A bushing having a shaft seal is disclosed herein. An example apparatus includes a fluid valve body (201), a valve shaft (206) disposed in the fluid valve body, and a bushing (502) disposed on the valve shaft between the valve shaft and the fluid valve body. The bushing includes a first groove (506) disposed on an inner surface of the bushing and a second groove (510) disposed on an outer surface of the bushing. A first seal (516) is disposed in the first groove to seal against the valve shaft and a second seal (514) is disposed in the second groove to seal against the valve body.