Ceramic Pressure Sensor Glass Solder Sealing
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Solution Overview
Problem
Ceramic pressure measuring arrangements face issues with diffusion-tight sealing due to the use of elastomer seals, leading to contamination and corrosion from gases and organic solvents, which affect measurement accuracy and sensor electronics.
Innovation Solution
A pressure measuring arrangement with a ceramic pressure measuring cell and process connection that uses a material bond, such as glass solder or glass frit, to create a diffusion-tight and pressure-tight connection, supported by a preload mechanism that absorbs compressive forces and includes a compensating element to manage thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastomer seals are used to seal the pressure measuring cell, then mechanical stress-free installation is ensured, but diffusion-tight sealing is compromised allowing gases and organic solvents to penetrate
Solution Approach 1:
The patent changes the material parameter of the sealing connection from elastomer to glass solder/glass frit, transforming the sealing mechanism from elastic deformation to material bonding. This parameter change achieves both mechanical stress-free installation through the flexible support arrangement and diffusion-tight sealing through the glass material properties.
Solution Approach 2:
The patent introduces a glass solder or glass frit as an intermediary material between the pressure measuring cell and the process connection. This intermediary material serves as both the sealing medium and the bonding agent, eliminating the need for elastomer seals while maintaining mechanical stress-free installation through the support arrangement.
2Reliability
If glass solder or glass frit is used to connect the pressure measuring cell and process connection, then diffusion-tight and pressure-tight connection is achieved, but tensile stresses and mechanical loads increase on the connection
Solution Approach 1:
The patent segments the mechanical load-bearing function from the sealing function. The glass solder/glass frit handles only the sealing and bonding function, while the support arrangement handles all mechanical load-bearing functions including tensile stresses, compressive forces, and lateral loads. This segmentation allows each component to be optimized for its specific function.
Solution Approach 2:
The support arrangement acts as an intermediary structure between the pressure measuring cell and the housing, absorbing mechanical loads before they reach the glass solder/glass frit connection. This intermediary support system protects the diffusion-tight connection from mechanical stress while maintaining sealing integrity.
3Reliability
If the support arrangement is made of materials that absorb compressive forces, then stability under high pressure is improved, but thermal expansion differences between ceramic and metal parts cause stress
Solution Approach 1:
The patent explicitly addresses thermal expansion by selecting materials for the support arrangement whose thermal expansion coefficients are compatible with the ceramic pressure measuring cell. The support arrangement is designed to accommodate thermal expansion differences, preventing stress buildup during temperature changes while maintaining mechanical stability under pressure.
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 solution prevents medium diffusion, ensures stability under high pressures, and allows for the use of cheaper materials for the support structure, while maintaining measurement accuracy and extending the range of usable pressures up to 100 bar.
Implementation Method 1
The connection between the pressure measuring cell and the process connection is advantageously established by means of a glass solder or a glass frit
Implementation Method 2
The connection between the pressure measuring cell and the process connection is advantageously established by means of a glass solder or a glass frit
Implementation Method 3
the support arrangement being designed in such a way that it absorbs compressive forces acting at least in the axial direction and induced by the measuring medium on the connection between the pressure measuring cell and the process connection
Implementation Method 4
an arrangement of the pressure measuring cell and the process connection is clamped in the direction of the housing against a step running in the housing and is thus held under preload
Implementation Method 5
the support arrangement having a fixing ring which engages over the process connection in the radial direction and is non-positively connected to the housing
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a pressure measuring arrangement (1) comprising a ceramic pressure measuring cell (5) which is arranged in a housing (3), and a ceramic process connection (7) arranged in the axial direction (A) and which is used for processing. Said pressure measuring cell (5) with the process connection (7) has a materially bonded connection (6).