Pressure Measurement Cell Stepped Recess Design
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Solution Overview
Problem
Conventional pressure measurement cells have a minimum distance of 25 micrometers between the base body and the measuring membrane due to the thickness of active solder foils, limiting the maximum allowable overpressure and measurement signal resolution.
Innovation Solution
A pressure measurement cell design that incorporates a stepped recess for the joining means, allowing the active solder foil to be partially inserted, thereby reducing the distance between the base body and the measuring membrane to a minimum, optimizing measurement performance by adjusting the step height and foil thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If active solder foil is used for joining the base body and measuring membrane, then the joining strength is improved, but the distance between base body and measuring membrane increases to at least 25 micrometers
Solution Approach 1:
The base body is segmented with a stepped recess that creates distinct levels. The active solder foil is placed in the first recess level, while the measurement chamber is formed at a second, higher level. This segmentation allows the solder to occupy only the lower recess space, reducing the overall distance between the base body surface and measuring membrane while maintaining adequate solder thickness for strong joining.
Solution Approach 2:
The invention transitions from a single-plane joining approach to a multi-level three-dimensional structure. By creating stepped recesses at different heights on the base body, the design utilizes vertical dimensionality to separate the joining function (at lower level) from the measurement function (at upper level), thereby reducing the effective distance for measurement while preserving joining integrity.
2Measurement precision
If the distance between base body and measuring membrane is reduced, then the measurement signal resolution is improved, but the maximum allowable overpressure decreases
Solution Approach 1:
The stepped recess structure segments the base body into functional zones: the first recess level accommodates the active solder foil for joining, while the second recess level provides the measurement chamber space. This segmentation enables the measuring membrane to be positioned closer to the base body (improving resolution) while the solder is confined to the lower recess, preventing it from interfering with the membrane's pressure response and maintaining overpressure tolerance.
3Length of moving object
If the active solder foil thickness is reduced, then the distance between base body and measuring membrane is reduced, but the joining reliability deteriorates
Solution Approach 1:
The stepped recess structure creates local quality variations in the base body geometry. The first recess level provides adequate space and confinement for the active solder foil, ensuring proper wetting and bonding behavior. This localized structural adaptation allows the use of thinner solder foils (reducing distance) while maintaining the soldering process reliability through optimized local geometry that promotes reliable joining.
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 reduced distance enhances measurement signal resolution and prevents membrane damage by allowing larger overpressures without tensile stress, achieving a suitable range of 5 to 15 micrometers for optimal performance.
Implementation Method 1
For joining the two bodies, meaning the base body and the measuring membrane, so-called active solders are used, which typically melt between 600 and 1000° C. and are usually processed at 800 to 1050° C.
Implementation Method 2
These solders are metallic solders that can, because of their alloy composition, wet non-metallic, inorganic materials.
Implementation Method 3
the capacitance between the at least one membrane electrode and the first base-body electrode is a function of the pressure-dependent position of the measuring membrane
Implementation Method 4
the measuring membrane is deflectable from a resting position of the measuring membrane into a pressure-dependent position as a function of a difference between a first pressure on an outer side of the measuring membrane facing away from the measurement chamber and a second pressure in the measurement chamber
Data Source
AI summary
A pressure measurement cell is disclosed including a base body, substantially cylindrical at least in sections, a measuring membrane joined to the base body in a pressure-tight manner along a perimeter joint to form a measurement chamber between the base body and the measuring membrane, and a joining material that joins the perimeter joint between the base body and the measuring membrane. The base body and/or the measuring membrane have/has a stepped recess into which the joining material is at least partially disposed, the stepped recess structured to yield a minimum distance between the base body and the measuring membrane.