Resin Pipe Fitting Sealing Through Differential Thermal Contraction
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Solution Overview
Problem
Resin tube fittings used in various industries face challenges in maintaining effective sealing capabilities after undergoing heat cycles, as the existing designs fail to adequately compensate for temperature changes, leading to compromised sealing performance.
Innovation Solution
The resin tube fitting design incorporates a body and inner ring made of resin with a higher radial contraction rate for the outer sleeve compared to the insert portion, ensuring the outer sleeve contracts more than the insert portion during temperature changes, thereby enhancing the sealing capability by pressing the sleeve onto the insert portion, forming a secure seal even at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the body and inner ring are made of resin with similar contraction rates, then the fitting is easy to manufacture, but the sealing capability deteriorates after heat cycles
Solution Approach 1:
The patent applies local quality by making the body and inner ring from resins with different contraction rates. Specifically, the body uses resin with a radial contraction rate of 0.03-0.06% while the inner ring uses resin with 0.01-0.04%, creating localized differential contraction properties that generate sealing pressure after heat cycles without requiring complex manufacturing processes.
Solution Approach 2:
The patent changes the material parameter (contraction rate) of the resin used in the body and inner ring. By selecting resins with specific contraction rate ranges and ensuring the body's contraction rate is higher than the inner ring's by 0.02% or more, the design exploits thermal contraction behavior to automatically generate sealing force after heat treatment, improving reliability without complicating manufacturing.
2Reliability
If the outer sleeve contracts more than the insert portion, then the sealing capability improves after heat cycles, but the dimensional precision requirements increase
Solution Approach 1:
The patent changes material parameters by selecting resins with specific contraction rate ranges (body: 0.03-0.06%, inner ring: 0.01-0.04%). This approach achieves the required differential contraction (0.02% or more) through material selection rather than precise dimensional control, reducing manufacturing precision requirements while ensuring reliable sealing after heat cycles.
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 significantly improves the sealing performance between the body and inner ring, maintaining a high level of sealing capability even after repeated heat cycles, as demonstrated by comparative experiments showing increased leakage limit pressure rates.
Implementation Method 1
the body and the inner ring are made of resin, which has a property of contracting in response to change in ambient temperature. A radial contraction rate of the outer sleeve of the body is designed to be higher by 0.09% or more than that of the insert portion of the inner ring.
Implementation Method 2
the body and the inner ring are made of resin, which has a property of contracting in response to change in ambient temperature
Data Source
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AI summary
A resin tube fitting (1) has: a body (11) with an outer sleeve (22); an inner ring (12) including an insert portion (32) insertable into the outer sleeve (22) to contact the outer sleeve (22) radially, and a press-in portion (31) configured to be pressed into a longitudinal end of the tube; and a union nut (13) configured to be engageable with the body (11). The body (11) and the inner ring (12) are made of resin, which has a property of contracting in response to change in ambient temperature. A radial contraction rate of the outer sleeve of the body is designed to be higher by 0.09% or more than that of the insert portion of the inner ring.