Countercurrent Leak Detection Bypass for Sensitivity and Fast Evacuation

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Solution Overview

Problem

Existing leak detection devices face conflicting requirements for high test gas sensitivity during normal operation and rapid evacuation of the detector in case of test gas contamination, as optimizing for high pumping speed and compression compromises detector sensitivity.

Innovation Solution

A bypass system is introduced that allows test gas to bypass at least part of the turbopump section, with adjustable conductivity to maintain high sensitivity during normal operation and enable rapid evacuation when needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the turbopump section is optimized for high pumping speed and high compression to enable rapid evacuation of the detector, then the evacuation capability is improved, but the test gas backflow to the detector is reduced, compromising detector sensitivity during normal operation

Engineering Contradiction:

Improveevacuation speedVSAvoiddetector sensitivity

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The turbopump section is divided into an upstream portion and a downstream portion relative to the test gas inlet. The upstream portion is optimized for high compression and pumping speed to enable rapid detector evacuation, while the downstream portion maintains lower compression to allow sufficient test gas backflow to the detector, thus resolving the contradiction between evacuation capability and detector sensitivity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the turbopump section are given different operational characteristics: the upstream portion operates at high compression for rapid evacuation, while the downstream portion operates at lower compression to preserve test gas backflow. This local differentiation of pump section properties allows simultaneous optimization of both evacuation speed and detector sensitivity

Inventive Principle:

Principle #3Local quality

2Productivity

If the turbopump section is optimized for high compression to pump out test gas quickly in case of contamination, then the evacuation capability is improved, but the test gas backflow is reduced, compromising normal leak detection sensitivity

Engineering Contradiction:

Improveevacuation efficiencyVSAvoidleak detection sensitivity

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The turbopump section is segmented into upstream and downstream portions with different compression characteristics. The upstream portion provides high compression for efficient evacuation when contamination occurs, while the downstream portion maintains lower compression to ensure adequate test gas backflow for sensitive leak detection during normal operation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adapts to different operational modes by utilizing the different compression characteristics of different pump sections. During normal operation, the downstream section's lower compression allows test gas backflow; during contamination events, the upstream section's high compression enables rapid evacuation, thus resolving the productivity-precision contradiction

Inventive Principle:

Principle #15Dynamics

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 bypass system ensures high test gas sensitivity during normal operation while allowing quick restoration of detector readiness in case of contamination, optimizing turbopump section for high compression and pumping speed without compromising detector performance.

Implementation Method 1

a turbo vacuum pump with a turbo pump section formed by one or more turbo pump stages

Methodology Applied

Scientific EffectTurbomolecular pumping:

Implementation Method 2

at least one bypass for the test gas is provided, which leads from a bypass outlet located at the level of the test gas inlet or upstream of the test gas inlet from the turbopump section directly into the detector

Methodology Applied

Scientific EffectGas flow through bypass:

Implementation Method 3

a detector, in particular a mass spectrometer, for detecting a test gas, in particular helium

Methodology Applied

Scientific EffectMass spectrometry:

Data Source

PatentEP4481354B1Leak detection apparatus and method

Publication Date: 2025.12.17 PFEIFFER VACUUM TECH AG

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Figure 2

AI summary

The invention relates to a device for leak detection using the countercurrent vacuum method, comprising a vacuum pump unit that can be connected to a test object to be evacuated and which includes a turbo vacuum pump with a turbo pump section formed by one or more turbo pump stages, and a detector for detecting a test gas, wherein the turbo vacuum pump is connected to the detector via at least one axial and/or radial suction inlet and has a test gas inlet downstream of the suction inlet, wherein at least a part of the turbo pump section is located between the suction inlet and the test gas inlet in the pumping direction of the turbo vacuum pump, and wherein at least one bypass for the test gas is provided.which leads from a bypass outlet from the turbopump section located at the level of the test gas inlet or upstream of the test gas inlet directly into the detector or to a bypass inlet into the turbopump section located upstream of the bypass outlet and which thereby bypasses at least part of the turbopump section.