Double-Tube Insulating Piping for Electrolyzer Leak Detection

Solution Overview

Problem

The electrical insulation of piping parts between water electrolysis stacks and auxiliary machines is inadequate when high voltage is applied, leading to potential leakage and damage, which complicates robustness and safety in large-scale hydrogen production systems.

Innovation Solution

An insulating piping system using a double tube configuration with an inner tube and an outer tube, where the outer tube encloses a dry gas at a higher pressure than the inner tube gas, ensuring insulation and rapid detection of damage through pressure and gas concentration sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single tube piping is used to connect water electrolysis stack and auxiliary machine, then the device complexity is low, but the electrical insulation reliability is insufficient when high voltage is applied

Engineering Contradiction:

Improveelectrical insulation reliabilityVSAvoidpiping structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The piping system is segmented into an inner tube and an outer tube, creating a dual-layer structure. The inner tube carries the fluid while the outer tube provides electrical insulation, separating the conductive and insulating functions into distinct segments. This segmentation resolves the contradiction by maintaining insulation reliability without excessive complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The inner tube is nested within the outer tube, forming a concentric double-tube structure. The insulating layer is positioned between the two tubes, creating a nested configuration that provides electrical insulation while maintaining a compact piping structure. This nesting approach achieves reliable insulation without significantly increasing device complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If no insulation structure is provided, then the device complexity is low, but hydrogen leakage risk increases when high voltage is applied

Engineering Contradiction:

Improvehydrogen leakage preventionVSAvoidinsulation structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The piping system is segmented into an inner tube and an outer tube, creating a dual-layer structure. The inner tube carries the fluid while the outer tube provides electrical insulation, separating the conductive and insulating functions into distinct segments. This segmentation resolves the contradiction by maintaining insulation reliability without excessive complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The inner tube is nested within the outer tube, forming a concentric double-tube structure. The insulating layer is positioned between the two tubes, creating a nested configuration that provides electrical insulation while maintaining a compact piping structure. This nesting approach achieves reliable insulation without significantly increasing device complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If damage detection system is not implemented, then the device complexity is low, but the ability to quickly identify piping damage is insufficient

Engineering Contradiction:

Improvedamage detection capabilityVSAvoiddetection system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Pressure sensors are installed in both the inner tube and outer tube to provide continuous feedback on the structural integrity of the piping system. When damage occurs, the pressure feedback mechanism detects the anomaly and triggers an alarm, enabling quick identification of piping damage. This feedback approach achieves reliable damage detection without excessive system complexity.

Inventive Principle:

Principle #23Feedback

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

Enhances the robustness of the water electrolysis system by preventing hydrogen leakage and quickly identifying damaged piping, thereby ensuring safe and efficient operation.

Implementation Method 1

with a pressure sensor that periodically detects a pressure in the outer tube inner space

Methodology Applied

Scientific EffectPressure detection:

Implementation Method 2

with a gas concentration meter that periodically detects a concentration of gas inside the inner tube

Methodology Applied

Scientific EffectGas concentration detection:

Data Source

PatentEP4596759A1Insulating piping, water electrolysis system, and piping damage detection method

Publication Date: 2025.08.06 HITACHI LTD

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Figure 2~3
Figure 4

AI summary

In order to improve robustness of a water electrolysis system, there is provided an insulating piping configured by a double tube including an inner tube (130) that connects a water electrolysis stack and an auxiliary machine and through which a fluid flows, and an outer tube (12) provided on an outer side of the inner tube (130) via the inner tube (130) and an outer tube inner space (14); in which the outer tube (12) has an insulating property, the water electrolysis stack and the auxiliary machine are insulated from each other in the inner tube (130), and a dry gas (13) having a humidity of less than or equal to a predetermined value is enclosed in an outer tube inner space (14) that is the space at a pressure of the fluid flowing inside the inner tube (130) and a pressure higher than an atmospheric pressure.