Inflatable Slit Valve Seal for Vacuum Chamber
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Solution Overview
Problem
Existing slit valve door seals in vacuum chambers rub against each other due to pressure differences, leading to particle generation and reduced seal life when the chamber body and door flex, causing contamination and frequent seal replacements.
Innovation Solution
Inflatable slit valve seals are used that can move laterally relative to their base, allowing the seal to roll without rubbing, thus accommodating the relative motion between the chamber body and door, reducing particle generation and extending seal life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid seals are used between the slit valve door and chamber body, then the seal provides a stable vacuum barrier, but the seal rubs against the surfaces when the door and chamber body move relative to each other due to pressure differences, generating particles and reducing seal life
Solution Approach 1:
The patent employs a flexible seal member comprising a seal plate and a seal member that can elastically deform. The seal member is attached to the slit valve door and can flexibly adapt to relative movements between the door and chamber body without generating particles, thus maintaining vacuum seal stability while eliminating the harmful rubbing effect of rigid seals
Solution Approach 2:
The patent changes the physical state of the seal from rigid to flexible by selecting appropriate material properties. The seal member is made of a material with specific elastic properties that allow it to deform under pressure differences, accommodating the relative motion between door and chamber body while maintaining sealing effectiveness and preventing particle generation
2Device complexity
If rigid seals are used between the slit valve door and chamber body, then the seal structure is simple, but the seal life is reduced due to rubbing caused by relative motion when the chamber is pumped down or vented
Solution Approach 1:
The flexible seal member is designed to accommodate relative movements between the slit valve door and chamber body through elastic deformation. This simple yet effective design eliminates rubbing wear that would otherwise occur with rigid seals, thereby extending seal life without significantly increasing structural complexity
Solution Approach 2:
The seal member is designed to be dynamically responsive to pressure changes and relative motion. Instead of being a static rigid component, the flexible seal adapts its shape and position in response to the dynamic conditions during pumping and venting cycles, preventing wear and extending service life
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 inflatable seals effectively reduce particle generation and extend the life of the seals by allowing the seal to roll with the movement of the chamber body and door, maintaining a vacuum seal without rubbing, thereby minimizing contamination and reducing maintenance needs.
Implementation Method 1
The hollow tubular portion of the first inflatable seal has a durometer of less than about 90 Shore A. The seal clamp has a recess having a width at least 5 percent wider than a width of the hollow tubular portion. The recess has an aperture through which the neck extends hollow tubular portion that can move laterally relative to the base, the width of the recess sufficient to allow the hollow tubular portion to roll relative to the base when the first slit valve door moves laterally relative to the base while the first slit valve door is in the closed position
Data Source
AI summary
Vacuum chambers having inflatable slit valve opening seals are described herein. In one example, a vacuum chamber includes a chamber body, a first inflatable seal, and a first slit valve door. The chamber body has a top, a bottom, and sidewalls. A first slit valve opening is formed in the sidewalls. The first inflatable seal is sealingly coupled to the sidewall and circumscribes the first slit valve opening. The first inflatable seal has a base coupled to the sidewall and a hollow tubular portion that can move laterally relative to the base. The first slit valve door is moveable between a close state that contacts the first inflatable seal to provide a vacuum seal between the first slit valve door and chamber body, and an open state that positions the first slit valve door clear of the first slit valve opening.