Two-Part Leak Testing for Closed Containers

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Solution Overview

Problem

Current methods for testing the tightness of closed containers, such as fuel rails, are inefficient in distinguishing between low-leakage and high-leakage rates, often requiring longer testing times and failing to accurately identify containers with trapped volumes and internal leaks.

Innovation Solution

A two-part testing method involving a fast leak rate test to identify compliant containers and a slower test to confirm compliance with stricter leak rate thresholds, utilizing a gas supply system, pressure sensor, and controller to measure leak rates over different time periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single slow testing method with strict leak rate thresholds is used, then measurement precision is improved, but productivity deteriorates due to longer testing times

Engineering Contradiction:

Improveleak rate detection accuracyVSAvoidtesting throughput

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The testing method is segmented into two distinct parts: a fast leak rate test with a first threshold and a slow leak rate test with a second threshold. This segmentation allows the system to quickly filter out clearly compliant containers using the fast test, while only subjecting potentially problematic containers to the more time-consuming slow test, thereby resolving the contradiction between measurement precision and productivity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The testing system dynamically adjusts the testing duration and threshold based on the results of the fast leak rate test. Containers that pass the fast test are quickly cleared, while those that fail are automatically subjected to the more rigorous slow test. This dynamic approach optimizes the balance between speed and accuracy for each individual container

Inventive Principle:

Principle #15Dynamics

2Productivity

If a fast testing method with longer testing times is used, then productivity is improved, but measurement precision deteriorates due to inability to accurately identify containers with trapped volumes

Engineering Contradiction:

Improvetesting speedVSAvoidleak rate identification accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The fast leak rate test serves as a preliminary screening step that quickly identifies containers with obvious leaks. By performing this initial fast test, the system can rapidly process containers that are clearly compliant without subjecting them to the longer slow test, thus maintaining high productivity while preserving measurement precision for containers that require detailed examination

Inventive Principle:

Principle #10Preliminary action

3Reliability

If all containers undergo slow testing with strict thresholds, then reliability is improved, but loss of time increases due to extended testing duration

Engineering Contradiction:

Improvecompliance determination accuracyVSAvoidtotal testing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The testing process is divided into two segments with different reliability requirements. The fast leak rate test provides a preliminary reliability check for quickly identifying compliant containers, while the slow leak rate test provides enhanced reliability for containers that fail the initial screen. This segmented approach ensures high overall reliability while minimizing time loss by avoiding unnecessary extended testing of clearly compliant containers

Inventive Principle:

Principle #1Segmentation

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 quickly identifies compliant containers with low-leakage rates, reducing overall testing time and accurately determining the leak rates of containers with trapped volumes and internal leaks, ensuring compliance with manufacturing standards.

Implementation Method 1

A pressure sensor measures a first leak rate of the closed container over a first period of time

Methodology Applied

Scientific EffectPressure measurement:

Data Source

PatentEP3423803B1Test methodology to reduce false rejections and increase number of containers tested for tightness

Publication Date: 2021.12.22 ROBERT BOSCH GMBH

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AI summary

A method and system of testing a tightness of a closed container using a two-part test. The first part of the two-part test includes connecting the closed container to a gas supply and filing the closed container with a testing gas from the gas supply. A first leak rate of the closed container is measured over a first period of time, and when the first leak rate is less than a first threshold, the controller identifies the closed container as compliant. Conversely, when the first leak rate is greater than the first threshold, the controller measures a second leak rate of the closed container over a second period of time. When the second leak rate is greater than a second threshold, the controller identifies the closed container as noncompliant, and when the second leak rate is less than the second threshold, the controller identifies the closed container as compliant.