Humidity Sensor Protective Tube Back Pressure Design
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Solution Overview
Problem
Existing moisture sensors in internal combustion engines face challenges in accurately measuring humidity due to contamination from water droplets, oil droplets, and dirt particles, which can impair the permeability of protective membranes and lead to temporary or permanent failure.
Innovation Solution
A sensor device with a protective tube that aligns perpendicular to the fluid flow, featuring an inflow path and outflow path within the tube, which creates a back pressure to prevent water and dirt from entering the measuring chamber, ensuring accurate humidity detection even in contaminated conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor element is directly exposed to the flowing fluid medium for accurate humidity detection, then measurement precision is improved, but the protective membrane becomes contaminated by water droplets, oil droplets, and dirt particles, leading to impaired permeability and sensor failure
Solution Approach 1:
The device divides the fluid medium interaction into separate functional zones: the protective tube handles direct fluid contact and contamination, while the measuring chamber maintains a clean environment for the sensor element. This segmentation allows the sensor to measure humidity through the protective membrane without direct exposure to contaminants.
Solution Approach 2:
The protective tube acts as an intermediary structure between the contaminated fluid medium and the sensor element. It creates a back pressure that prevents water and dirt from reaching the measuring chamber, while still allowing water vapor to pass through the protective membrane for humidity detection.
2Reliability
If the protective membrane is used to shield the sensor element from contaminants, then reliability is improved, but the membrane's permeability is impaired by contamination, leading to loss of humidity measurement capability
Solution Approach 1:
The device separates the protection function (performed by the protective tube and outer membrane) from the measurement function (performed by the sensor element in the measuring chamber). This allows the protective membrane to be more robust and less permeable, while the sensor remains protected from direct contamination.
Solution Approach 2:
The protective tube creates back pressure beforehand to prevent water and dirt droplets from reaching the protective membrane and sensor element. This pre-protection mechanism ensures that the membrane maintains its permeability properties over time.
3Adaptability or versatility
If the sensor device is placed in harsh environments with high water content or particle contamination, then adaptability is improved, but the sensor element and protective membrane become contaminated, leading to measurement failure
Solution Approach 1:
The device architecture separates the harsh environment interface (protective tube) from the sensitive measurement zone (measuring chamber). This segmentation enables the sensor to operate reliably in harsh environments by preventing contaminant ingress while maintaining humidity detection capability.
Solution Approach 2:
The protective tube serves as an intermediary barrier that allows the sensor device to adapt to harsh environments. It filters out water and dirt particles while permitting water vapor transmission, enabling reliable operation in contaminated conditions.
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 effectively prevents contamination of the sensor element and protective membrane, allowing for reliable and accurate humidity measurement in harsh environments, including those with high water content or particle contamination.
Implementation Method 1
A sensor device with a protective tube that aligns perpendicular to the fluid flow, featuring an inflow path and outflow path within the tube, which creates a back pressure to prevent water and dirt from entering the measuring chamber
Implementation Method 2
the sensor device proposed therein incorporates a humidity sensor or a humidity module, which, together with the sensor device, is introduced into a flow channel of a fluid medium. Within the flow channel, the entire fluid medium flows past the semipermeable membrane of the humidity sensor
Data Source
Figure 1~1B
Figure 2
Figure 3
AI summary
The invention relates to a sensor device (10) for detecting a humidity of a flowing, liquid medium which comprises at least one humidity module (32) having at least one sensor element (42) for recording the humidity and at least one protective membrane (44) shielding the sensor element (42), wherein the sensor device (10) furthermore has at least one housing (30), wherein the humidity module (32) is arranged at least partially in a measurement chamber (40) of the housing (30). The housing (30) preferably has a protective tube (16), protruding in an axial direction (34a) into the flowing, liquid medium perpendicular to the prevailing primary flow direction (12), wherein the protective tube (16) has at least one inflow path (36). The inflow path (36) is designed such that the liquid medium can flow through the inflow path (36) against the axial direction (34b) into the measurement chamber (40) and can flow out the at least one outflow path (38) beyond in the axial direction (34a) out of the measurement chamber (40). The at least one outlet opening (48) and the at least one inlet opening (46) are below in the direction of gravity.