Environmental enclosure for a gas sensor for use in a transport vehicle
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Solution Overview
Problem
The use of moderate-to-low global warming potential (GWP) refrigerants in air conditioning systems poses risks due to their mild flammability, and existing technologies lack effective leak detection systems, particularly for HVAC&R products, which can lead to undesirable consequences if refrigerant leaks occur.
Innovation Solution
A refrigerant detection assembly that includes a housing with an internal cavity connected to the ambient atmosphere, a non-dispersive infrared sensor, a printed circuit board, and a heat conduction plate, along with insulators and a breathable film, designed to detect refrigerant leaks in refrigeration systems using A2L refrigerants, capable of detecting leaks within specific flammability limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a refrigerant detection assembly is designed with environmental robustness, then detection reliability in harsh conditions improves, but device complexity increases
Solution Approach 1:
The detection assembly is segmented into distinct functional modules: a housing containing the infrared sensor, a separate breathable film for selective gas permeation, insulation layers for thermal management, and mounting structures. This segmentation allows each component to be optimized for its specific function while simplifying assembly and maintenance
Solution Approach 2:
A breathable film is introduced as an intermediary element between the external environment and the sensor chamber. This film allows refrigerant gases to pass through while blocking liquid contaminants and moisture, providing environmental protection without requiring complex sealed enclosures
2Reliability
If the detection assembly is protected from environmental contaminants, then sensor reliability improves, but gas permeability may be reduced
Solution Approach 1:
The patent employs a breathable film with controlled porosity that selectively permits refrigerant gas molecules to pass through while blocking larger liquid droplets and particulate contaminants. This porous structure enables the sensor to detect gas-phase refrigerant leaks while being protected from liquid 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 detection assembly effectively identifies refrigerant leaks in refrigeration systems, providing rapid detection of leaks within ten seconds of exposure to 100% lower flammability limit, ensuring environmental safety and operational reliability.
Implementation Method 1
a non-dispersive infrared sensor operably coupled to the air chamber
Implementation Method 2
a heat conduction plate mechanically and thermally coupled to the printed circuit board
Implementation Method 3
At least one insulator is arranged within the internal cavity at a position between a portion of the subassembly and the housing
Implementation Method 4
a film disposed in overlapping arrangement with the opening, wherein the film is permeable to gas and impermeable to liquid
Data Source
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AI summary
A refrigerant detection assembly (50) operable to detect refrigerant mixed with air. The refrigerant detection assembly (50) includes: a housing (52) having an internal cavity (62) fluidly connected with an ambient atmosphere surrounding the housing (52) via an opening (84); a subassembly (64) mounted within the internal cavity (62) that includes: an air chamber (72) fluidly connected with the internal cavity (62), a non-dispersive infrared sensor operably coupled to the air chamber (72), a printed circuit board (74), and a heat conduction plate (76) mechanically and thermally coupled to the printed circuit board (74). At least one insulator (80) is arranged within the internal cavity (62) at a position between a portion of the subassembly (64) and the housing (52). A shell (86) is connectable to the housing (52) in overlapping arrangement with the opening (84). The shell (86) has at least one shell opening (88) formed therein such that a flow path extends from the shell opening (88), through the opening (84) formed in the housing (52) to the internal cavity (62), and into the air chamber (72).