Air-Lock Valve Frame Sealing for Strip Processing
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Solution Overview
Problem
Existing air-lock valves in band coating plants face issues such as damage to the band substrate due to contact with narrow passage slots during oscillations, rupture under high tensile stress, and seal deficiencies under extreme pressure differences, leading to incomplete sealing and potential coating damage during vacuum evacuation.
Innovation Solution
An air-lock valve with a frame-like sealing face and a moveable, mechanically operated body that surrounds the opening, allowing for complete closure independent of the band substrate's presence, featuring an arcuate shape and flexible material to minimize substrate bending and ensure reliable sealing without direct contact during substrate changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a narrow passage slot is used in the air-lock valve, then the seal can be compact and the valve can close completely, but the band substrate may contact the passage borders during oscillations causing damage to the coating and rupture of the substrate
Solution Approach 1:
The sealing function is divided into two independent parts: the frame-like sealing face that provides the sealing surface, and the moveable body that performs the closing action. This segmentation allows the passage slot to be wider while maintaining effective sealing, as the sealing face remains stationary and does not restrict substrate movement.
Solution Approach 2:
The frame-like sealing face acts as an intermediary between the moveable body and the band substrate. It provides a stable sealing surface that distributes contact pressure and prevents direct contact between the substrate and the moveable body borders, thereby avoiding substrate damage during oscillations.
2Strength
If the hollow seal is built firmly to withstand extreme pressure differences in vacuum, then the seal can resist the pressure stress, but the flexibility of the seal is reduced causing seal deficiencies at the marginal areas
Solution Approach 1:
The moveable body is covered with a flexible sealing film that can deform to accommodate pressure differences and substrate movements. This flexible covering maintains seal completeness at marginal areas while the overall structure withstands the extreme pressure differences through its rigid frame construction.
Solution Approach 2:
The sealing structure combines rigid and flexible materials: the frame-like sealing face and moveable body provide structural strength to resist pressure, while the flexible sealing film ensures complete sealing at the margins. This composite approach resolves the contradiction between strength and flexibility.
3Reliability
If a mechanically operated body with arcuate shape is used, then the substrate bending is minimized and sealing is improved, but the device complexity increases compared to simple tube seals
Solution Approach 1:
The moveable body is given an arcuate shape that matches the curvature of the band substrate. This curved geometry allows the substrate to pass through with minimal bending, reducing mechanical stress and improving sealing effectiveness. The arcuate form naturally conforms to the substrate shape, enhancing the sealing contact.
4Reliability
If the passage slot is kept narrow to limit the stroke of the seal, then the seal can close completely, but the substrate may contact the passage borders during oscillations causing coating damage
Solution Approach 1:
The sealing system is segmented into a stationary frame-like sealing face and a moveable closing body. This allows the passage slot to be wider than in traditional designs, as the sealing face does not need to traverse the entire passage width. The moveable body closes the gap without its borders contacting the substrate, preventing coating damage.
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 solution reduces the risk of substrate damage and rupture, maintains a sealed vacuum environment, and prevents coating damage by allowing a larger gap and using flexible materials to ensure effective sealing without the need for fluidic pressure-operated valves, ensuring reliable operation during spool changes.
Implementation Method 1
featuring an arcuate shape and flexible material to minimize substrate bending and ensure reliable sealing without direct contact during substrate changes
Implementation Method 2
the unilateral atmospheric pressure (from the respectively ventilated chamber) acts upon the seal, forcing it into the vacuum chamber
Data Source
AI summary
An air-lock valve (1), especially for a band processing plant, provided for closing a gap-like opening (3), traversed by a flexible band substrate (4), between two different plant sections, featuring at least one moveable sealing body (7), cooperating with a sealing surface (5), when it closes said opening (3), and eventually said band substrate (4) is being firmly mounted between said body (7) and sealing surface (5) during the closing operation of said air-lock valve (1), is characterized, according to the invention, in that the sealing surface (5) surrounds opening (3) in frame-like fashion, and in order to close opening (3), said body (7) may be pressed in such a fashion upon sealing surface (5) and/or upon band substrate (4), traversing said opening (3), that it obstructs said opening (3) at least due to indirect juxtaposition at the edges of said sealing surface (5).