Dynamic Sealing Joint for Brittle Pipes Under Thermal Expansion
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Solution Overview
Problem
Existing fluid handling systems using brittle materials like graphite are prone to mechanical failure due to thermal expansion and contraction, especially in high-temperature and corrosive environments, as they do not bend or yield before fracture, leading to pipe fracture or rupture.
Innovation Solution
A dynamically sealed joint structure for brittle materials, comprising a packing shell with sealing elements and compression rings, allowing for translation or rotation of pipes while maintaining a seal, using materials with similar thermal expansion coefficients to stabilize the seal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ductile materials are used for piping, then the piping can absorb thermal expansion through bending and stretching, but the piping cannot withstand high temperatures above 1000°C or corrosive environments
Solution Approach 1:
The piping system is divided into discrete pipe sections connected by expansion joints. Each section can independently expand and contract, allowing the overall system to accommodate thermal expansion while using brittle high-temperature materials like graphite or ceramics that cannot themselves bend or yield.
Solution Approach 2:
Expansion joints serve as intermediary components between pipe sections. These joints contain sealing elements that allow relative movement while maintaining the seal, enabling brittle pipe materials to expand and contract without mechanical failure while still containing the process fluid.
2Reliability
If expansion joints are added to allow thermal expansion, then mechanical failure is prevented in ductile materials, but brittle materials still fracture because they cannot bend or yield
Solution Approach 1:
Expansion joints act as intermediaries that absorb all the mechanical stress from thermal expansion. The sealing elements within these joints are designed to accommodate movement through friction and controlled deformation, protecting the brittle pipe materials from any bending or yielding stresses that would cause fracture.
Solution Approach 2:
The sealing elements in expansion joints are designed with specific friction characteristics and compliance properties that allow them to accommodate thermal expansion through controlled sliding and deformation. This changes the mechanical parameter distribution so that brittle pipes experience only axial stress, not bending moments.
3Ease of manufacture
If static seals are used in joints, then assembly is simple, but the joints cannot accommodate thermal expansion and contraction
Solution Approach 1:
The seals transition from static to dynamic configurations. Expansion joints incorporate sealing elements that can move relative to each other while maintaining contact, allowing the seal to dynamically adapt to thermal expansion and contraction. This maintains simplicity of assembly while enabling movement accommodation.
4Reliability
If compression is applied to sealing elements to ensure a tight seal, then leakage is prevented, but thermal expansion may alter the seal pressure
Solution Approach 1:
The expansion joint structure is designed to accommodate thermal expansion of the piping system while maintaining seal pressure. The compression rings and sealing elements are configured so that thermal expansion moves the pipes relative to each other within the joint, rather than changing the compression force on the seals. This decouples thermal expansion from seal pressure variation.
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 joint structure prevents mechanical failure by accommodating thermal expansion and contraction, ensuring a tight seal and preventing leakage in high-temperature environments, thus extending the lifespan and reliability of the system.
Implementation Method 1
manage and reduce stresses induced by thermal expansion and contraction of a joint structure
Implementation Method 2
A dynamically sealed joint structure for brittle materials, comprising a packing shell with sealing elements and compression rings
Data Source
AI summary
A joint structure may include a first component and a second component aligned in a first direction, where a first end of the first component is opposed to a first end of the second component. The joint structure may include a packing shell positioned around the first end of the first component and the first end of the second component such that the first component is inserted into the packing shell from the first end and the second component is inserted into the packing shell from the first end. The joint structure may include a first sealing element positioned between the packing shell and the first end of the first component and further extending into the packing shell. The joint structure may include a second sealing element positioned between the packing shell and the first end of the second component and further extending into the packing shell.