Relative-Pressure Sensor Drying Chamber for Moisture Control
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Solution Overview
Problem
Relative pressure sensors face challenges in maintaining dry conditions within the sensor to prevent moisture condensation, especially when exposed to temperature fluctuations, due to the reference pressure supply allowing ambient air to enter, leading to rapid saturation of desiccants and difficulties in ensuring only dried air reaches the measuring element.
Innovation Solution
A drying module with a container enclosing moisture-adsorbing material, where only the bottom surface is partially permeable to moisture, reduces moisture absorption rates and eliminates the need for additional moisture-limiting elements like hoses and glass bushings, allowing for slower saturation and easier storage, while ensuring effective drying near the evaluation unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reference pressure supply allows ambient air to enter the sensor, then atmospheric pressure can be supplied to the measuring element, but moisture condensation occurs inside the sensor when exposed to temperature fluctuations
Solution Approach 1:
A drying chamber filled with moisture-absorbing material is introduced as an intermediary component between the reference pressure supply opening and the measuring element. This drying chamber acts as a mediator that allows atmospheric pressure to reach the measuring element while simultaneously absorbing moisture from the ambient air, preventing condensation on the measuring element and evaluation unit.
Solution Approach 2:
The drying chamber is strategically positioned only in the region where moisture condensation is most problematic (near the evaluation unit and measuring element), while other parts of the sensor maintain their original structure. This localized approach addresses the harmful effect of moisture condensation without unnecessarily complicating the entire sensor design.
2Object-affected harmful factors
If a drying chamber with moisture-absorbing material is added to prevent moisture condensation, then moisture protection is improved, but the device complexity increases
Solution Approach 1:
The drying chamber is integrated into the existing sensor housing structure, merging the moisture absorption function with the structural components of the sensor. The drying chamber utilizes the existing reference pressure supply passage and housing space, combining multiple functions (structural support, moisture absorption, and pressure reference supply) into a unified design rather than adding separate independent components.
Solution Approach 2:
The container for the moisture-absorbing material is designed as a simple chamber within the housing, utilizing thin-walled structures that are easy to manufacture and integrate. The container may be formed as a simple cavity or using thin-walled injection molding, avoiding complex rigid structures while effectively enclosing the moisture-absorbing material.
3Reliability
If additional moisture-limiting elements like hoses and glass bushings are used, then moisture protection is improved, but the device complexity and assembly difficulty increase
Solution Approach 1:
The invention extracts and eliminates the need for complex moisture-limiting elements such as hoses and glass bushings by directly integrating the drying chamber into the sensor housing. This removal of unnecessary intermediate components simplifies the overall structure and significantly eases assembly, while maintaining effective moisture protection through the integrated drying chamber.
4Object-affected harmful factors
If the drying chamber is designed with large size to ensure effective moisture absorption, then moisture protection is improved, but the volume of the sensor increases
Solution Approach 1:
The drying chamber is designed with just sufficient volume to absorb moisture effectively in the critical region near the evaluation unit, rather than oversized dimensions. The moisture-absorbing material is placed only where it is most needed (in the path of ambient air entering through the reference pressure supply), providing adequate moisture protection with minimal volume occupation.
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 moisture absorption, extends the dry module's service life, simplifies assembly, and saves space and material by minimizing the size of the drying module, while ensuring reliable operation by maintaining dry conditions within the sensor.
Implementation Method 1
at least one drying chamber arranged in the housing for absorbing atmospheric humidity from the ambient air supplied through the reference pressure supply
Implementation Method 2
A bottom surface of the container facing the measuring element is at least partially moisture-permeable
Data Source
Figure 1
Figure 2a~2b
AI summary
The invention relates to a relative-pressure sensor (1) for determining the pressure (p1) of a medium (2) in relation to an atmospheric pressure (p2), the sensor comprising a housing (3) having a measuring element (4) located in the housing (3), wherein the pressure (p1) to be measured acts upon an outer surface of the measuring element (4), said surface being in contact with the medium (2), a reference-pressure supply (5), which supplies an inner surface of the measuring element (4) with atmospheric pressure (p2) in the form of ambient air, an evaluation unit (6), which determines the pressure (p1) of the medium (2) from a variable determined using the measuring element (4), and comprising a take-up of atmospheric humidity from the ambient air that is supplied via the reference-pressure supply (5). The drying chamber (7) has a drying module (8) comprising a container (9) and a humidity-adsorbing material (10) that is completely surrounded by the container (9).