Gas Sensor Housing with Thin PTFE Membrane
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Solution Overview
Problem
Current gas sensor housings are not well-suited for high-speed gas detection and leak testing due to increased response time and risk of mechanical impact and contamination, as they often require additional filter barriers that slow down diffusion and increase thickness, leading to longer recovery times and reduced sensitivity.
Innovation Solution
A gas sensor housing design featuring a primary gas permeable membrane with a minimized separation distance from the gas sensor and optional secondary membrane for electrical insulation, along with a metal mesh for protection, to reduce diffusion distance and internal volume, thereby enhancing response speed and recovery time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fine filter (diffusion membrane) is placed in front of the sensing element to protect against contamination, then the sensor is protected from particle contamination, but the response time increases and detection speed decreases
Solution Approach 1:
The patent uses a thin PTFE membrane as the diffusion barrier, optimizing its thickness to balance protection and response time. The membrane is thin enough to allow rapid gas diffusion while still providing effective particle filtration, resolving the contradiction between protection and speed.
Solution Approach 2:
The patent changes the physical parameters of the diffusion barrier by using a PTFE membrane with specific porosity (30-70%) and thickness (10-50 μm). These parameter optimizations allow the membrane to provide adequate protection while maintaining fast response times of 1-10 seconds.
2Reliability
If additional filter barriers are added to protect the sensor in harsh environments, then protection against mechanical impact and contamination is improved, but the diffusion distance increases and recovery time increases
Solution Approach 1:
The patent employs a thin PTFE membrane instead of thick or multiple filter barriers. This single thin film provides sufficient protection against contamination while minimizing diffusion distance, enabling recovery times of 10-60 seconds compared to traditional sensors.
Solution Approach 2:
The patent extracts the essential protective function and implements it through a single optimized PTFE membrane, eliminating the need for multiple layered barriers. This extraction reduces overall diffusion distance and internal volume while maintaining protection.
3Speed
If the sensing element is positioned close to the leakage site for rapid detection, then detection speed is improved, but the risk of mechanical impact and contamination increases
Solution Approach 1:
The thin PTFE membrane serves as a protective shell that allows the sensing element to be positioned close to the leakage site for rapid detection while filtering out particles and protecting against contamination. The membrane's thinness ensures minimal diffusion delay.
Solution Approach 2:
The PTFE membrane provides beforehand protection by filtering contaminants and mechanically protecting the sensing element before exposure to harsh environments, enabling the sensor to operate close to leakage sites without risk of damage or contamination.
4Strength
If a standard sensor housing is used to protect the sensing element, then mechanical protection is provided, but the housing thickness and internal volume increase diffusion distance and reduce sensitivity
Solution Approach 1:
The patent replaces thick standard housing structures with a thin PTFE membrane for the critical gas diffusion path. This thin film provides necessary protection while minimizing diffusion distance, maintaining high sensitivity for detecting low concentration gases.
Solution Approach 2:
The PTFE membrane acts as a selective barrier that allows gas molecules to pass through via diffusion while blocking particles. The membrane's porous structure optimizes gas permeability while providing mechanical protection, reducing housing thickness requirements.
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
This design significantly reduces the time needed to establish gas concentration on the sensor surface, improving detection speed and reducing the risk of contamination, with recovery times decreased to around 10 seconds compared to 60-70 seconds in traditional sensors.
Implementation Method 1
gas may reach the sensor through directing a flow of sample gas onto an active surface of the sensing element... The diffusion principle is very robust but still suffers from a few drawbacks, such as slower establishment of the correct gas mixture on the active surface
Implementation Method 2
a metal mesh for protection
Implementation Method 3
a spacer section providing a separation distance between the gas sensor and the primary gas permeable membrane... to reduce diffusion distance and internal volume
Data Source
Figure 1
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AI summary
The present invention relates to gas sensor housing (1), comprising: a gas sensor (3) held by a housing body (11) below a primary gas permeable membrane (2); at least one connector element (10) moulded into the housing body (11) such that the respective ends thereof enable connectivity to the gas sensor (3) such that signals may be carried from the gas sensor (3) to the connector element (10); a sensor envelope (9) providing an enclosure for the housing body (11); means for retaining the primary gas permeable membrane (2) in place above the gas sensor (3); a spacer section (7) providing a separation distance (X) between the gas sensor (3) and the primary gas permeable membrane (2).