Membrane-Sealed Press Fitting for High-Pressure Conduit Joints
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Solution Overview
Problem
Existing crimp connections in HVAC/R conduit systems are prone to leaks and separation, especially at high pressures, due to imperfections and damage on the copper conduit surfaces, which affect the sealing ability of O-ring seals.
Innovation Solution
A connection joint with a tubular body featuring membrane seals having bulbous portions and radially inwardly extending ribs, which engage the exterior surface of conduits, and a crimping mechanism that ensures metal-to-metal contact on opposing sides of the seals for a robust seal, even at high pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing crimp connections with O-ring seals are used, then installation time is reduced compared to brazing, but the connection becomes prone to leaks and separation at high pressures due to conduit surface imperfections
Solution Approach 1:
The seal is divided into multiple independent sealing elements: an inner O-ring seal and an outer membrane seal with bulbous portions. Each seal operates independently to provide redundant sealing, so if one seal is compromised by surface imperfections, the other maintains seal integrity. This segmentation resolves the contradiction by maintaining high installation speed while improving reliability through multiple sealing mechanisms.
Solution Approach 2:
The membrane seal with radially inwardly extending ribs acts as an intermediary between the fitting body and the conduit surface. The ribs engage with the conduit exterior to provide a sealing interface that is less sensitive to surface imperfections, while the bulbous portions provide additional sealing contact. This intermediary structure enables reliable high-pressure sealing without sacrificing installation speed.
2Device complexity
If a single O-ring seal is used in crimp connections, then the device complexity is low, but the seal fails at high working pressures greater than 700 psi
Solution Approach 1:
The sealing function is segmented into two distinct seals: an inner O-ring seal for basic sealing and an outer membrane seal with bulbous portions and radially inwardly extending ribs for high-pressure sealing. This segmentation allows the system to handle pressures greater than 700 psi while maintaining relatively simple installation procedures.
Solution Approach 2:
The membrane seal is made of flexible material that can deform to accommodate conduit surface variations while maintaining seal integrity under high pressure. The flexible membrane with bulbous portions conforms to the conduit exterior, providing reliable sealing at pressures exceeding 700 psi without significantly increasing device complexity.
3Reliability
If the membrane seal is positioned close to the open end for effective engagement, then sealing effectiveness improves, but the seal may be damaged during conduit insertion
Solution Approach 1:
The membrane seal is pre-positioned within the fitting body at an optimal location before conduit insertion. The bulbous portions are预先 configured to engage the conduit exterior at the correct position, ensuring effective sealing while being protected from damage during insertion. This preliminary positioning resolves the contradiction by maintaining seal effectiveness while preventing installation damage.
Solution Approach 2:
The membrane seal structure includes bulbous portions that provide cushioning protection during conduit insertion. These bulbous portions absorb insertion forces and protect the critical sealing surfaces from damage, while still enabling effective sealing engagement once the conduit is properly inserted. This beforehand cushioning maintains both sealing effectiveness and seal durability.
Data Source
AI summary
A connection joint for coupling a pair of conduits. The connection joint includes a tubular body having an inlet end and an outlet end that are each configured for receipt of a respective conduit therein. A first membrane seal is located within the tubular body and spaced apart from the inlet end, and a second membrane seal is located within the tubular body and spaced apart from the outlet end. The first and second membrane seals each have a bulbous portion located proximate the inlet end and outlet end, respectively, a tubular sleeve unitary with the bulbous portion located away from the inlet end and outlet end, respectively, and a plurality of radially inwardly extending ribs.