Clean Room Light Fixture Sealing With Knife-Edge Filter Interface
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Solution Overview
Problem
Existing light fixtures for clean rooms often fail to provide a sealed environment, allowing unfiltered gas to pass between the ceiling plenum and the clean room, compromising the controlled atmosphere.
Innovation Solution
A light fixture design featuring a base plate with sealingly attached side walls and end plates, gas filters with knife portions, and a light channel secured without creating unfiltered gas paths, using continuously welded or monolithic connections and sealed wiring conduits to ensure a filtered atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing light fixtures are installed in clean room ceiling plenums, then lighting function is provided, but unfiltered gas passes between the ceiling plenum and clean room compromising the controlled atmosphere
Solution Approach 1:
The light fixture is divided into separate sealed components: a base portion attached to the ceiling plenum, a light channel portion containing the light source, and a diffuser portion. Gas filters are integrated at the interface between the ceiling plenum and the light fixture base, segmenting the gas flow path to ensure all gas passes through filtration media before entering the clean room.
Solution Approach 2:
Gas filters serve as intermediary elements positioned between the ceiling plenum and the clean room environment. These filters act as mediators that allow gas flow while removing contaminants, and sealing members (gaskets, adhesives, or welded joints) serve as intermediaries to create sealed connections between components, preventing unfiltered gas leakage.
2Reliability
If sealed connections are implemented to prevent unfiltered gas passage, then controlled atmosphere is maintained, but device complexity increases
Solution Approach 1:
Flexible gaskets and sealing films are used to create sealed connections between the light fixture components and the ceiling plenum. These flexible sealing elements can accommodate minor misalignments and surface irregularities, providing reliable seals without requiring complex rigid sealing structures or precision machining.
Solution Approach 2:
The light fixture incorporates composite construction with different materials optimized for specific functions: metal or plastic for structural components, transparent or translucent materials for the diffuser, filtering media for gas filtration, and elastomeric materials for sealing. This composite approach allows each material to perform its specific function efficiently while simplifying the overall sealing system design.
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 effectively seals the gas path between the ceiling plenum and the clean room, maintaining a controlled atmosphere within the clean room by preventing air leakage and ensuring the integrity of the filtered environment.
Implementation Method 1
A downstream end of the first leg may form a first-leg knife portion which is spaced from the light-fixture base. The first leg may extend from the first end to the second end of the light-fixture base. A first gas filter may comprise an orthogonal first gas-filter frame defining an interior perimeter and an exterior perimeter. The trough may have a sealant affixed therein, with the first-leg knife portion penetrating an outer surface of the sealant to form a seal between the light-fixture base and the first gas filter.
Data Source
AI summary
A light fixture, for a ceiling plenum system defining an upstream space and a downstream space, includes a light-fixture base defining a light-fixture axis. First and second side walls extend toward the downstream space and are sealingly attached to the base plate and to first and second end plates. First and second legs are sealingly attached to the light-fixture base by one of a first-leg continuously welded joint and a first-leg monolithic connection. A downstream end of each leg forms a knife portion. First and second gas filters each comprise an orthogonal gas-filter frame defining an interior perimeter and an exterior perimeter. A trough with sealant affixed therein is sealingly attached to and surrounds a portion of the exterior perimeter. A trough opening faces the downstream space, with the knife portions penetrating surfaces of the sealant, forming a seal between the light-fixture base and each gas filter.