Pressure Sensor Insulating Cell Convex Seal Design
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Solution Overview
Problem
Conventional sensor body cells for differential pressure sensors experience cracking and increased manufacturing costs due to tensile stresses caused by thermal expansion differences between metal housings and glass insulating cells during the glassing operation.
Innovation Solution
The sensor body cells incorporate insulating cells with seal portions that have convex conical outer surfaces corresponding to concave conical inner surfaces of the metal housing, reducing tensile stresses and the likelihood of cracking during the cooling phase of the glassing operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass or ceramic insulating cell is fused within metal housing during glassing operation, then electrical insulation and sealing are provided, but tensile stresses cause cracking of the insulating cell
Solution Approach 1:
The patent changes the geometric parameters of the conical surfaces by introducing a specific convex curvature to the glass-to-metal seal outer surface. This curvature parameter modification allows the seal to better accommodate thermal expansion differences between the glass insulating cell and metal housing during cooling, reducing tensile stresses and preventing cracking while maintaining sealing integrity.
Solution Approach 2:
The patent applies curvature to the glass-to-metal seal by forming its outer surface with a convex shape that corresponds to the concave conical inner surface of the metal housing. This curved geometry distributes thermal stress more evenly during the cooling phase of the glassing operation, preventing the tensile stresses that would otherwise cause cracking in flat or conventional designs.
2Ease of manufacture
If conventional glassing operation is used with flat conical surfaces, then manufacturing process is simple, but tensile stresses increase cracking likelihood and manufacturing costs
Solution Approach 1:
The patent introduces a convex curved surface to the glass-to-metal seal that corresponds to the concave conical inner surface of the housing. This curvature is integrated into the glassing process itself, allowing the molten glass to conform to the shaped cavity during fusion. The curved geometry prevents cracking during cooling, eliminating the need for post-manufacturing repairs or rework, thereby improving manufacturing efficiency without significantly complicating the glassing operation.
3Reliability
If insulating cell is sealed within metal housing, then pressure sensor integrity is maintained, but thermal expansion differences create tensile stresses
Solution Approach 1:
The patent modifies the geometric parameters of the seal interface by creating a convex curved outer surface on the glass-to-metal seal that corresponds to the concave conical inner surface of the metal housing. This geometric parameter change allows the seal to better accommodate the differential thermal expansion between the glass insulating cell and metal housing during cooling, reducing the tensile stresses generated by thermal expansion mismatches while maintaining pressure sensor integrity.
Solution Approach 2:
The patent applies curved geometry to the glass-to-metal seal interface, where the convex outer surface of the seal corresponds to the concave inner surface of the housing. This curvature allows the seal to flex and accommodate thermal expansion differences more effectively during the cooling phase, reducing tensile stresses that would otherwise compromise the insulating cell while maintaining the sealed integrity of the pressure sensor.
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 reduces the likelihood of cracking in the insulating cells, thereby increasing manufacturing efficiency and reducing costs, while maintaining the integrity of the pressure sensor under high line pressures.
Implementation Method 1
the glass provides electrical insulation between the electrodes and the cell body
Implementation Method 2
tensile stresses caused by differences in rates of thermal expansion between the insulating cell and the metal housing
Data Source
Figure 1
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AI summary
A sensor body cell (144A) for use in a pressure sensor (122) includes a metal housing and an insulating cell (150A). The metal housing (146) has a first cavity (154A) with a first conical inner surface (179). A portion of the first conical inner surface (179) is concave. The insulating cell (150A) includes a first seal portion (170) within the first cavity (154A) and forms a seal with the first conical inner surface (179).