Spin Welding Hermetic Seals for Submerged Endpoints
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Solution Overview
Problem
Automatic meter reading endpoints, especially those submerged in water, tend to fail due to moisture permeation and condensation on electronic components, leading to data transmission issues.
Innovation Solution
A hermetically sealed endpoint is created using a spin welding procedure that forms a hermetic seal between a housing, lid, and collar, utilizing chamfers for an interference fit and preventing moisture vapor entry, with the components made from materials like thermoplastic or stainless steel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sealing methods are used for endpoints submerged in water, then the device can be manufactured with simpler processes, but moisture permeation occurs leading to condensation on electronic components and device failure
Solution Approach 1:
The spin welding process utilizes melting and solidification phase transitions of the thermoplastic material. The collar is rotated at high speed against the housing, generating friction heat that melts the thermoplastic material at the interface. When the rotation stops, the melted material solidifies, forming a hermetic seal that prevents moisture permeation and protects electronic components from condensation.
Solution Approach 2:
The invention changes physical parameters during the sealing process - specifically temperature and rotational speed. The spin welding process temporarily increases the temperature of the sealing interface through friction heat generation, then allows it to cool and solidify. The rotational speed parameter is controlled to generate sufficient heat for melting while maintaining process control, creating a reliable hermetic seal.
2Reliability
If the endpoint housing is made hermetically sealed to prevent moisture entry, then reliability improves, but the manufacturing process becomes more complex requiring spin welding procedures
Solution Approach 1:
The endpoint device is segmented into distinct components - the housing, the collar, and the lid - that can be manufactured separately and then joined through spin welding. This segmentation allows each component to be optimized independently while the hermetic seal between them provides moisture protection. The collar acts as a separate sealing element that interfaces with both the housing and the lid.
Solution Approach 2:
The sealing structure utilizes composite construction combining different materials - the thermoplastic collar material that melts and seals with the housing material, and the stainless steel or alternative material lid that provides additional protection. This composite approach enables hermetic sealing while maintaining structural integrity and corrosion resistance in the aquatic environment.
3Manufacturing precision
If chamfers are used to create interference fit for spin welding, then the hermetic seal quality improves, but the manufacturing precision requirements increase
Solution Approach 1:
The chamfer geometry is applied locally at the sealing interface of the collar component, specifically at the regions that contact the housing and lid. This localized geometric feature creates the interference fit necessary for hermetic sealing during spin welding, while the rest of the components can be manufactured with standard tolerances. The local quality enhancement is concentrated where it is most needed for seal formation.
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 spin welding method significantly reduces moisture vapor permeation, enhancing the reliability and longevity of the endpoints by preventing failures associated with water exposure.
Implementation Method 1
the collar may be rotated relative to and driven against the housing and/or the lid to heat the respective parts until the collar is welded and/or coupled to the housing and the lid
Implementation Method 2
heat the respective parts until the collar is welded and/or coupled to the housing and the lid
Implementation Method 3
the examples disclosed herein are sealed (e.g., hermetically sealed) using an example spin welding procedure. The example sealed (e.g., hermetically sealed) end points substantially reduces the moisture vapor rate permeating the end point through mating component joints of the end point
Data Source
AI summary
Sealed end points and methods of making the same are disclosed. An example method includes disposing a first flange of a lid within a groove of a housing. The groove is defined by first and second walls of the housing and lid. The method also includes means for welding two stationary components while rotating a third component to weld the three components together. The second flange is positioned between the first flange and the first wall. The housing, the lid, and the collar include a thermoplastic material. The method includes securing the housing and the lid relative to one another and spin welding the housing, the lid, and the collar.