Diaphragm Measuring Element With Inner Hydrogen Barrier Layer
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Solution Overview
Problem
In industrial processes, hydrogen-rich media can permeate through diaphragms in remote measuring devices, leading to inaccurate measurements and potential diaphragm damage due to pressure deviations, especially in harsh conditions like high temperature and corrosiveness.
Innovation Solution
A hydrogen permeation-resistant layer, such as a gold-plated layer, is applied to the inner side surface of the diaphragm, extending beyond the connection region with the base body, to prevent hydrogen from entering the sealed cavity, while avoiding contact with the medium to be measured, thereby enhancing measurement accuracy and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a diaphragm is used to separate the medium from the sealed cavity, then pressure measurement can be performed, but hydrogen from the medium can permeate through the diaphragm causing measurement inaccuracy and potential diaphragm damage
Solution Approach 1:
The diaphragm is segmented into multiple functional layers: an outer layer facing the medium, an inner layer facing the sealed cavity, and a hydrogen permeation resistant layer positioned between them. This segmentation allows each layer to perform its specific function - the outer layer contacts the medium, the hydrogen permeation resistant layer blocks hydrogen, and the inner layer transmits pressure - thereby preventing hydrogen permeation while maintaining pressure measurement capability and diaphragm integrity
Solution Approach 2:
A hydrogen permeation resistant layer is introduced as an intermediary between the medium-facing diaphragm surface and the sealed cavity. This intermediate layer acts as a barrier that selectively blocks hydrogen permeation while allowing pressure transmission, thus protecting the sealed cavity from hydrogen contamination and preventing diaphragm damage without compromising measurement functionality
2Measurement precision
If a hydrogen permeation resistant layer is applied to the outer side of the diaphragm to prevent hydrogen permeation, then measurement accuracy improves, but the layer is exposed to wear from the medium reducing service life
Solution Approach 1:
Instead of applying the hydrogen permeation resistant layer to the outer side of the diaphragm that contacts the medium, the layer is inverted and positioned on the inner side facing the sealed cavity. This inversion protects the hydrogen permeation resistant layer from wear by the medium while still effectively blocking hydrogen permeation, thereby extending service life while maintaining measurement accuracy
Solution Approach 2:
The hydrogen permeation resistant layer is applied only to the specific region of the diaphragm where hydrogen permeation occurs - the inner side facing the sealed cavity - rather than coating the entire diaphragm or outer surface. This localized application protects against hydrogen permeation while avoiding exposure to wear from the medium, optimizing both measurement accuracy and service life
3Reliability
If the hydrogen permeation resistant layer is extended beyond the connection region of the diaphragm with the base body, then hydrogen permeation is completely blocked, but manufacturing complexity increases
Solution Approach 1:
The hydrogen permeation resistant layer is applied to the diaphragm before the diaphragm is assembled and welded to the base body. This preliminary application ensures that the layer extends continuously beyond the connection region, completely blocking hydrogen permeation paths at the weld seams, while allowing standard welding processes to be used without requiring complex post-assembly modifications
4Reliability
If a thick hydrogen permeation resistant layer is applied to the diaphragm, then hydrogen permeation is effectively blocked, but material costs and manufacturing complexity increase
Solution Approach 1:
The hydrogen permeation resistant layer is applied with a thickness that is sufficient to block hydrogen permeation (at least 1μm, preferably 5-10μm) but not excessively thick. This partial action approach provides adequate hydrogen barrier protection while avoiding the increased material costs and manufacturing complexity associated with very thick coatings, achieving an optimal balance between effectiveness and manufacturability
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 significantly improves measurement accuracy, extends the service life of the measuring device, reduces material costs, and simplifies production and maintenance by ensuring a zero hydrogen permeation path without increasing manufacturing complexity.
Implementation Method 1
a hydrogen permeation resistant layer arranged on an inner side surface, facing the sealed cavity, of the diaphragm
Implementation Method 2
a first weld along an interior radius of the diaphragm which seals the diaphragm to the base body in the connection region
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present disclosure is provided with a measuring element (M) and a measuring device. The measuring element includes a base body (1), a diaphragm (2) and a permeation resistant layer (4), the diaphragm is fixedly connected to the base body (1), with a sealed cavity (3) being defined between the diaphragm (2) and the base body (1). The permeation resistant layer (4) is arranged on an inner side surface (21), facing the sealed cavity (12), of the diaphragm, and extended continuously on the inner side surface (21) of the diaphragm (2) at least beyond a connection region of the diaphragm with the base body. The measuring device includes the measuring element (M).