Hydrogen Permeability Testing of Non-Metallic Pipes
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Solution Overview
Problem
Current hydrogen permeability tests for non-metallic pipes are inefficient due to low test rates and inaccurate calculations, primarily because non-metallic pipes have lower bearing strength and deform under pressure, leading to volume changes in sealed test chambers, which affects hydrogen concentration and pressure readings.
Innovation Solution
The apparatus and method involve circumferential and axial reinforcement of the test cylinder to maintain constant volume in sealed test chambers, allowing for higher hydrogen pressure testing without deformation, using a test cylinder with reinforcement pieces and a high-pressure gas source to increase hydrogen permeation and detection efficiency, and calculating permeability based on pressure detection values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-metallic pipes are used for hydrogen conveying, then corrosion resistance and service life are improved, but hydrogen permeability increases causing safety issues
Solution Approach 1:
The patent introduces a test chamber as an intermediary environment to measure hydrogen permeability. The test chamber isolates the pipe section and allows controlled hydrogen exposure, enabling detection of permeation rates without direct hydrogen contact with the testing system. This mediator approach quantifies the harmful permeability effect while preserving the pipe's corrosion resistance benefits.
2Productivity
If high pressure is applied to increase hydrogen permeation rate, then test efficiency is improved, but pipe deformation occurs affecting measurement accuracy
Solution Approach 1:
The patent applies counteracting forces through the test chamber design. Reinforcement rings are installed on the pipe within the test chamber to counterbalance the high internal pressure applied during testing. These rings prevent radial expansion and axial elongation of the pipe, maintaining dimensional stability despite high pressure conditions, thus preserving measurement accuracy while enabling efficient high-pressure testing.
Solution Approach 2:
The patent changes the physical state parameters of the testing environment by controlling temperature and pressure within the test chamber. By maintaining constant temperature conditions and applying controlled high pressure with compensation mechanisms, the system optimizes hydrogen permeation rate for faster testing while preventing pipe deformation through parameter management.
3Loss of time
If test pressure is increased to reduce testing time, then testing speed is improved, but volume changes in test chamber affect hydrogen concentration calculations
Solution Approach 1:
The reinforcement rings in the test chamber serve as counterweights against pressure-induced volume changes. By mechanically constraining the pipe expansion, the system prevents test chamber volume variation even at high pressures. This allows rapid high-pressure testing while maintaining accurate volume measurements for hydrogen concentration calculations.
Solution Approach 2:
The patent replaces mechanical volume measurement methods with pressure-based detection. Pressure sensors continuously monitor the test chamber conditions, and hydrogen concentration is calculated based on pressure changes rather than direct volume measurements. This substitution eliminates errors from volume changes and enables faster data acquisition at high pressures.
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 approach significantly increases test efficiency by detecting hydrogen pressure changes faster and provides more accurate hydrogen permeability calculations by maintaining constant volume and applying higher hydrogen pressures without affecting accuracy, thus improving the overall testing process.
Implementation Method 1
a vacuum pump configured to be connected with the sealed test chambers through a vacuumization tube to extract the gas from the sealed test chambers
Implementation Method 2
a high pressure gas source configured to communicate with an interior of the to-be-tested pipe through a gas inlet tube to introduce test gas into the to-be-tested pipe
Implementation Method 3
a plurality of circumferential reinforcement pieces are disposed on a circumferential inner wall surface of the cylindrical body of the test cylinder and configured to be in contact with an outer surface of the to-be-tested pipe placed in the test cylinder and perform circumferential reinforcement on the to-be-tested pipe
Data Source
AI summary
Methods, apparatus, and systems for testing a hydrogen permeability of a non-metallic pipe are provided. In one aspect, an apparatus for testing a hydrogen permeability of a non-metallic pipe includes: pipe sealing pieces, a test cylinder, a high pressure gas source, a gas exhaust tube, a vacuum pump, and a pressure sensor. A plurality of circumferential reinforcement pieces are disposed on a circumferential inner wall surface of a cylindrical body of the test cylinder to be in contact with an outer surface of a to-be-tested pipe placed in the test cylinder and perform circumferential reinforcement on the to-be-tested pipe.