Capillary Tube Leak Detection for Coolant-Condensation Separation

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Solution Overview

Problem

Existing liquid leak detection systems, particularly for battery pack coolants, suffer from false alarms due to inability to differentiate between coolant leakage and condensation, leading to potential safety risks and efficiency reductions.

Innovation Solution

A leak detection apparatus using a capillary tube and pressure sensor to measure air pressure, coupled with computing devices to distinguish coolant from other liquids based on viscosity differences and capillary rise differentiation, with temperature compensation to adjust pressure thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If resistive sensors are used to detect liquid leakage, then leakage detection capability is provided, but false alarms occur due to inability to distinguish coolant from condensation

Engineering Contradiction:
Improveleakage detection accuracyVSAvoidliquid identification precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by utilizing the difference in viscosity parameters between coolant and condensation. The capillary tube leverages the viscosity-dependent capillary action to differentiate liquids: coolant with higher viscosity rises slower and to lower heights, while condensation with lower viscosity rises faster and higher. This viscosity-based parameter differentiation enables accurate liquid identification without false alarms

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the electrical resistive sensing mechanism with a mechanical capillary action-based system. Instead of using resistive sensors that cannot distinguish liquid types, the invention employs capillary tubes where liquid rise height and speed mechanically indicate liquid identity. This mechanical substitution enables both leakage detection and liquid differentiation simultaneously

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If capillary tube with pressure sensor is used to differentiate liquids by viscosity, then liquid identification precision is improved, but device complexity increases

Engineering Contradiction:
Improveliquid identification precisionVSAvoiddetection apparatus complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The capillary tube performs self-service by automatically differentiating liquids through passive capillary action driven by viscosity differences. No active pumping or complex actuation is needed—the tube itself serves as both the detection medium and the differentiation mechanism. The pressure sensor simply reads the resulting pressure, which naturally varies with liquid type

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The capillary tube serves multiple functions simultaneously: it acts as the detection channel for liquid presence, the differentiation mechanism for liquid identification, and the pressure transmission medium for sensor reading. This multi-functionality reduces overall device complexity compared to using separate components for each function

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If temperature compensation is implemented to adjust pressure thresholds, then detection reliability under varying temperatures is improved, but control system complexity increases

Engineering Contradiction:
Improvedetection reliability under temperature variationVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements feedback by using the temperature sensor to continuously monitor temperature conditions and automatically adjusting the pressure threshold accordingly. When temperature rises, the threshold increases to account for expanded air pressure; when temperature drops, the threshold decreases. This closed-loop feedback maintains detection reliability across temperature variations

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system applies parameter changes by dynamically adjusting the pressure threshold parameter based on temperature measurements. The control algorithm modifies the threshold parameter in response to temperature changes, ensuring accurate detection despite thermal expansion or contraction of air in the capillary tube

Inventive Principle:
Principle #35Parameter changes

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

Accurately detects coolant leaks while minimizing false alarms by differentiating coolant from condensation and other liquids, ensuring safety and maintaining battery pack efficiency.

Implementation Method 1

a capillary tube a first end configured to immerse in the liquid of interest in the spill collector

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a second end configured to mechanically couple with a pressure sensor, the pressure sensor configured to measure an air pressure in the capillary tube

Methodology Applied
Scientific EffectPressure measurement:

Data Source

PatentEP4614130A1Systems, apparatuses, and methods for leak detection using a capillary tube
Publication Date: 2025.09.10 HONEYWELL INTERNATIONAL INC
  • EP4614130A1 patent drawingFigure 1
  • EP4614130A1 patent drawingFigure 2
  • EP4614130A1 patent drawingFigure 3

AI summary

In some examples, a leak detection apparatus is described herein. In one or more example embodiments, the leak detection apparatus includes a spill collector configured to collect a liquid of interest from a leakage of the liquid of interest. In one or more examples, the leak detection apparatus alternatively or additionally includes a capillary tube a first end configured to immerse in the liquid of interest in the spill collector; and a second end configured to mechanically couple with a pressure sensor, the pressure sensor configured to measure an air pressure in the capillary tube. In one or more examples, the leak detection apparatus alternatively or additionally includes one or more computing devices electronically coupled with the pressure sensor, the one or more computing devices configured to distinguish the liquid of interest from another liquid using the measured air pressure in the capillary tube.