Vacuum Valve Shaft Feedthrough With Bellows Sealing

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Solution Overview

Problem

Existing vacuum valves suffer from grease and gas entrainment, high wear, and high cost due to the use of shaft feedthroughs with O-rings and magnetic fluid-sealing mechanisms, which are inefficient and costly.

Innovation Solution

A shaft feedthrough design using a bellows and a shaft-sealing ring, where the bellows allows expansion and contraction parallel to the shaft axis, and the shaft-sealing ring allows rotation, reducing relative movement and minimizing grease and gas entrainment, while being cost-effective.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If O-rings are used in the shaft feedthrough to seal the shaft, then sealing is achieved, but grease and gas entrainment occurs and wear increases

Engineering Contradiction:

Improvesealing performanceVSAvoidgrease and gas entrainment

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention extracts the harmful interaction between the shaft and sealing rings by introducing a bellows that isolates the shaft from direct contact with the valve housing sealing environment. The bellows absorbs the shaft's linear movements, preventing the shaft from rubbing against O-rings and eliminating grease and gas entrainment.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The bellows acts as an intermediary element between the shaft and the valve housing. It provides a flexible barrier that allows shaft movement while maintaining sealing, preventing direct contact between the shaft and any sealing rings, thus eliminating the harmful effects of friction and entrainment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If magnetic fluid-sealing mechanisms are used to seal the shaft, then sealing is improved, but device complexity and cost increase

Engineering Contradiction:

Improvesealing performanceVSAvoidshaft feedthrough complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention replaces complex, expensive magnetic fluid-sealing mechanisms with a simple, cost-effective bellows structure. The bellows is a mechanically simple component that achieves the same sealing function without the complexity and high cost of magnetic fluid systems.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention substitutes complex magnetic fluid-sealing mechanisms with a purely mechanical bellows structure. The bellows uses simple elastic deformation to achieve sealing and accommodate shaft movement, replacing the need for magnetic fields and complex sealing systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the shaft is sealed with O-rings allowing rotation and linear movement, then operational flexibility is maintained, but wear and grease entrainment increase

Engineering Contradiction:

Improveshaft movement freedomVSAvoidshaft service life

Core Design Contradiction:

Ease of operationVSDuration of action of moving object

Solution Approach 1:

The invention segments the shaft movement into two independent components: linear movement is absorbed by the bellows expansion/contraction, while rotational movement is isolated from the sealing interface. This segmentation allows the shaft to rotate and move linearly without causing wear at the sealing location.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bellows provides dynamic sealing that adapts to the shaft's movements. As the shaft moves linearly, the bellows expands or contracts accordingly, maintaining the sealing barrier without creating friction or wear. The system dynamically adjusts to accommodate full operational flexibility while preventing wear.

Inventive Principle:

Principle #15Dynamics

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

The design provides enhanced sealing and durability with reduced abrasion and cost, allowing for effective operation in vacuum technology environments.

Implementation Method 1

a bellows (11), which can be expanded and pushed together in the directions parallel to the longitudinal axis of the shaft

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

there is relative movement between the shaft-sealing ring and shaft only in a circumferential direction of the shaft, but not in a longitudinal direction of the shaft

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS12422056B2Valve, in particular a vacuum valve

Publication Date: 2025.09.23 VAT HOLDING AG

AI summary

A valve on which a valve plate is arranged in a valve housing interior space of a valve housing and fixed to a shaft, in which the valve plate together with the shaft can be displaced back and forth in directions parallel to a shaft longitudinal axis between a closed position and an intermediate position, and by rotation of the shaft about the shaft longitudinal axis can be pivoted back and forth between the intermediate position and a maximum open position. A shaft leadthrough for sealing the shaft with respect to the valve housing has a bellows which can be expanded and pushed together in the directions parallel to the shaft longitudinal axis, a first bellows end of this bellows being fixed to the valve housing, and a shaft sealing ring in which the shaft is rotatably mounted, being arranged on a second bellows end.