Tubular Membrane Header Sealing for High-Pressure Heat Exchangers
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Solution Overview
Problem
Sealing membrane tubes in tubular heat exchangers is challenging due to small size and large numbers, leading to potential leaks and limited water flow rates, which restricts heat and mass transfer properties and working pressure.
Innovation Solution
A tubular membrane assembly with a header, fittings, and potting that forms a secure fluid-tight connection, allowing for variable spacing and supporting flexible membranes under high pressures, using gas-permeable and liquid-impermeable materials with airflow assistance for efficient heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membrane tubes are sealed using traditional methods (welding, rolling, braising, gluing, or potting), then the heat exchanger can be assembled, but the seal strength is insufficient leading to leaks and limited working pressure
Solution Approach 1:
The patent uses a composite sealing structure combining potting material and a reinforcement element (such as a ferrule or metal sleeve) that is embedded in the potting. This composite approach provides both the flexibility needed for adhesion and the mechanical strength to withstand high working pressures, resolving the contradiction between seal reliability and pressure resistance.
2Area of stationary object
If small-sized membrane tubes are used to increase heat transfer surface area, then heat and mass transfer properties improve, but sealing becomes more difficult due to small size and large numbers
Solution Approach 1:
The potting material is applied in a liquid or semi-liquid state that flows around and adapts to each small membrane tube automatically, then hardens to form a unified sealing matrix. This self-service approach eliminates the need for individual sealing operations on each small tube, making the manufacturing process feasible despite the large number of components.
Solution Approach 2:
The patent merges the sealing function for all membrane tubes into a single potting operation that creates a unified sealing structure. Rather than sealing each tube separately, the potting material bonds multiple tubes together and to the end caps in one process, significantly reducing manufacturing complexity.
3Adaptability or versatility
If inconsistent or flexible tubes are used, then adaptability to different configurations is improved, but uneven gaps between tubes and tube sheets create leaks
Solution Approach 1:
The patent changes the physical state of the sealing material from rigid to flexible/liquid, allowing it to adapt to varying tube positions and gaps. The potting material can flow into uneven spaces and conform to the actual geometry, maintaining seal integrity despite tube inconsistencies while preserving configuration flexibility.
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 solution provides durable connections that enable efficient heat and mass transfer under high pressures, optimizing heat exchanger configuration and performance by preventing leaks and enhancing seal strength.
Implementation Method 1
tubular membranes that facilitate heat transfer between two fluids
Implementation Method 2
gas-permeable and liquid-impermeable materials
Data Source
AI summary
In one aspect, a tubular membrane assembly is provided for a heat exchanger. The tubular membrane assembly includes a header having a header body, a tubular membrane, and a fitting connecting the tubular membrane to the header body. The fitting is configured to form a fluid tight connection between the fitting and the tubular membrane. The tubular membrane assembly further includes potting of the header keeping the tubular membrane connected to the fitting.