Sniffing Leak Detector Flow Divider for Helium Leakage
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Solution Overview
Problem
Conventional sniffing leak detectors have a limited measurement range for helium leakage rates due to restricted signal stability at lower rates and potential contamination at higher rates, requiring complex turbomolecular pumps and sudden failures.
Innovation Solution
The sniffing leak detector incorporates a flow divider and valve/throttle system to manage gas flow, allowing simultaneous connection of the sniffing line to the suction chamber and vacuum line, and a venting valve for ambient air influx, maintaining a working pressure of 250 mbar and enabling wider leakage rate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mass-spectroscopy methods are used for high detection sensitivity, then detection sensitivity is improved, but device complexity increases due to requirement of turbomolecular pumps
Solution Approach 1:
The patent extracts the test gas (helium) from the complex mass-spectroscopy system and detects it using a simple pressure sensor. By removing the complicated pump and spectroscopy system, the invention achieves leak detection without requiring turbomolecular pumps, thus reducing device complexity while maintaining detection capability through a different physical principle (pressure measurement instead of mass spectroscopy).
Solution Approach 2:
The patent replaces expensive, complex, and fragile mass-spectroscopy equipment with a simple, inexpensive pressure sensor that can withstand higher pressures. This substitution allows the system to operate in a less restrictive pressure environment, eliminating the need for complex vacuum pumps and reducing overall system cost and complexity.
2Quantity of substance
If the measurement range is extended to higher leakage rates, then measurement range is improved, but sensor contamination risk increases
Solution Approach 1:
The patent changes the operating pressure parameter from high vacuum (10^-4 mbar) to moderate pressure (250 mbar). This parameter change allows the system to handle higher leakage rates (up to 10^-1 mbar l/s) without contaminating the sensor, as the pressure sensor is not sensitive to helium contamination in the same way mass spectrometers are. The flow divider simultaneously manages gas flow to maintain this optimal pressure range.
Solution Approach 2:
The flow divider acts as an intermediary device that regulates and distributes the gas flow. It controls the amount of test gas reaching the sensor, preventing excessive helium accumulation that would cause contamination. By mediating the gas flow between the leak source and sensor, it enables measurement of higher leakage rates while protecting the sensor.
3Quantity of substance
If the measurement range is extended to lower leakage rates, then measurement range is improved, but signal stability deteriorates
Solution Approach 1:
The patent changes the pressure parameter to 250 mbar, which provides optimal signal stability for detecting low leakage rates. At this pressure, the pressure sensor achieves sufficient sensitivity and signal stability that was not available at ultra-high vacuum conditions, enabling reliable detection of small leaks while maintaining stable measurements.
4Object-affected harmful factors
If a venting valve is used to flush helium from sensor surface, then sensor protection is improved, but device complexity increases
Solution Approach 1:
The flow divider serves as an intermediary that naturally manages gas flow distribution. It directs a portion of the gas flow to the sensor for measurement while allowing excess gas to be vented through the vacuum line, eliminating the need for complex valve systems. The flow divider passively regulates flow without requiring additional control valves or complex mechanisms.
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 configuration expands the detection range for helium leakage rates, prevents contamination, and ensures reliable operation by maintaining a stable working pressure and efficient gas exchange, overcoming limitations of existing technologies.
Implementation Method 1
A vacuum pump (13) creates a vacuum in a suction chamber (15)
Implementation Method 2
a test gas sensor (16) having a suction chamber (15) in front of a sensor surface (17)
Implementation Method 3
a flow divider (30) allows to simultaneously connect the sniffing line (11) to the suction chamber (15) of the test gas sensor (16) via a suction line (14) and to the vacuum line (14) via the open valve (V4)
Implementation Method 4
the suction chamber (15) arranged downstream of the test gas sensor (16) is connected to a venting valve (V3) through which ambient air can be sucked in. In this way, helium can be flushed away from the sensor surface (17)
Implementation Method 5
A desired working pressure of about 250 mbar can be generated and maintained in front of the sensor surface (17) by a suitable valve/throttle system
Data Source
AI summary
To achieve a large measurement range from small up to larger leakage rates, a switchover from normal operation to gross operation occurs. In gross operation, the sucked-in gas flow is separated by different throttles, wherein the throttle that leads to the test gas sensor has a low flow rate. This manner of operation prevents a too large quantity of test gas from reaching the sensor surface and contaminating the sensor. In another alternative, in gross operation the test gas flows only across a part of the sensor surface. The other part is flushed.