Thermal Sensor Ball Seal for Leak-Resistant TXV Charging
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Solution Overview
Problem
Conventional thermostatic expansion valves face issues with leakage during the charging and sealing process of the thermal sensor assembly, requiring additional materials, labor, and equipment to mitigate leakage, and involving complex manipulation of flexible charging tubes.
Innovation Solution
A ball seal is implemented in the charge opening of the thermal sensor assembly enclosure, where the ball forms a fluid seal between a sealing surface and interface, with the sealing interface formed by a harder material and the sealing surface by a softer material, eliminating the need for a charge tube and reducing leakage risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flexible charging tube is used to charge the sensing fluid into the bulb, then the charging process can be performed, but the flexible tube requires manipulation that can cause leakage of the sensing fluid
Solution Approach 1:
The patent removes the flexible charging tube from the system entirely. Instead, a rigid charging conduit is used that is brazed directly to the bulb assembly, eliminating the manipulation step that causes leakage while maintaining the ability to charge the sensing fluid into the bulb.
Solution Approach 2:
The charging conduit is brazed directly to the bulb assembly, merging the charging function with the bulb structure. This integration eliminates the separate flexible tube component and its associated sealing problems, creating a more reliable sealed system.
2Reliability
If additional sealing materials and equipment are used to prevent leakage during tube manipulation, then leakage can be mitigated, but the assembly complexity and cost increase
Solution Approach 1:
The patent eliminates the need for additional sealing materials and equipment by removing the flexible charging tube from the system. The rigid brazed connection provides inherent sealing without requiring extra components, thereby reducing assembly complexity while maintaining reliability.
3Reliability
If a rigid charging conduit is used instead of a flexible tube, then manipulation and leakage issues are eliminated, but the charging process becomes less flexible
Solution Approach 1:
The rigid charging conduit is pre-installed and brazed to the bulb assembly before the charging process. This preliminary installation eliminates the need for manipulation during charging, as the conduit is already in its final position, providing both reliability and operational simplicity.
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 ball seal simplifies the assembly process, reduces leakage, and minimizes the need for additional materials and equipment, enhancing the sealing capability and reliability of the thermal sensor assembly.
Implementation Method 1
the sealing surface is formed by a second material having a greater softness than the first material such that the sealing surface conforms to the sealing interface and fluidly seals the thermal sensing fluid
Data Source
AI summary
A thermal sensor assembly for a thermostatic expansion valve includes an enclosure that forms an enclosed interior space containing a thermal sensing fluid, and an opening in the enclosure for charging the thermal sensing fluid. A ball is arranged in the opening and forms a fluid seal between a sealing surface and a sealing interface of the assembly. The sealing surface may be made with a material that is softer than a material of the sealing interface, such that the sealing surface conforms to the sealing interface and fluidly seals the thermal sensing fluid in the enclosed interior space of the enclosure. The opening may include a tapered lead-in hole that tapers radially inwardly as the lead-in hole extends toward the interior space to thereby form the seal. A cover may be attached to an exterior surface of the enclosure to hold the ball in the opening to form the seal.