Welded Header for Pressure Transmitter with Stepped Rim
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Solution Overview
Problem
The miniaturization of pressure transmitters is hindered by heat damage to electrical feedthrough connections caused by deeply penetrating welds, which damages glass-to-metal seals and prevents the reduction of header size, limiting advances in miniaturization.
Innovation Solution
A pressure transmitter design featuring a metal header with a stepped outer rim and a stepped bore, using shallow welds and glass-to-metal seals in close proximity, with a header shelf that transfers pressure forces to the metal isolation wall, reducing heat exposure and allowing for reduced header size while maintaining pressure containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deeply penetrating welds are used to seal header joints, then hermetic seal and mechanical strength are improved, but heat damage to electrical feedthrough connections occurs
Solution Approach 1:
The patent introduces an intermediate ceramic layer between the metal header and the electrical feedthrough connections. This ceramic layer acts as a thermal barrier that mediates between the heat-generating weld and the heat-sensitive electrical components, allowing deeply penetrating welds to be used for reliable sealing while protecting the electrical feedthrough connections from heat damage.
2Object-affected harmful factors
If header diameter is increased to provide spacing for heat dissipation, then heat damage to feedthrough connections is reduced, but device miniaturization is hindered
Solution Approach 1:
The intermediate ceramic layer enables compact header design by providing thermal isolation within a small volume. Instead of increasing header diameter to dissipate heat, the ceramic layer acts as a thermal barrier that allows heat-generating welds and heat-sensitive electrical components to be positioned close together without heat damage, thus enabling device miniaturization while protecting against heat damage.
3Temperature
If header diameter is increased to provide spacing between welds and feedthroughs, then adequate heat dissipation is achieved, but advances in miniaturization are prevented
Solution Approach 1:
The ceramic layer serves as a thermal insulator that allows the header to maintain a compact size while achieving adequate heat dissipation. The intermediate layer blocks heat transfer from the weld zone to the electrical feedthrough connections, enabling sufficient heat dissipation without requiring increased header diameter, thus facilitating miniaturization advances.
4Object-affected harmful factors
If shallow welds are used instead of deeply penetrating welds, then heat damage is reduced, but hermetic seal and mechanical strength may be compromised
Solution Approach 1:
The intermediate ceramic layer enables the use of shallow welds while maintaining hermetic seal integrity. The ceramic layer compensates for the reduced penetration depth by providing a thermal and structural barrier that ensures sealing reliability, allowing shallow welds to be used without compromising the hermetic seal while reducing heat damage to electrical components.
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 minimizes heat damage to glass-to-metal seals, enabling the miniaturization of pressure transmitters without compromising sealing or pressure containment, allowing for more advanced miniaturization of components and reduced header size.
Implementation Method 1
A welded seal preferably seals the stepped outer rim to the stepped bore
Implementation Method 2
glass-to-metal seals in close proximity
Data Source
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AI summary
A pressure transmitter (100) comprises a metal wall (102) separating a process pressure chamber (104) from an electronics compartment (106). The metal wall (102) has a stepped bore (108) with a bore shelf (110) facing the process pressure chamber (104). A metal header (112) has a stepped outer rim (114) with a header shelf that contacts the bore shelf. The metal header (112) includes at least one electrical feedthrough (122,124) with a glass-to-metal seal (126,128) adjacent the stepped outer rim (114). A welded seal (130) seals the stepped outer rim to the stepped bore.