Leakage Seeker Flow Sensor Protection via Buffer Volume
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flow sensors in leak detectors are prone to damage due to pressure surges generated by feed pumps, particularly positive-displacement pumps, which can lead to clogging and inaccurate readings.
Innovation Solution
Incorporating a gas buffer volume and a gas throttle between the feed pump and the flow sensor acts as a low-pass filter, dampening pressure surges and protecting the flow sensor from damage. The buffer volume is at least three times the scoop volume of the feed pump, and the throttle maintains a pressure drop of less than 100 mbar, effectively filtering out pressure surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a positive-displacement feed pump is used to continuously feed gas to the gas detector, then the gas supply function is improved, but pressure surges occur that damage the flow sensor
Solution Approach 1:
A buffer volume is introduced as an intermediary component between the feed pump and the flow sensor. This buffer volume absorbs the pressure surges generated by the positive-displacement pump before they reach the flow sensor, thereby protecting the sensor while maintaining continuous gas supply functionality.
Solution Approach 2:
The buffer volume is positioned upstream of the flow sensor to cushion pressure surges before they can damage the sensor. This preemptive cushioning approach prevents damage by absorbing pressure fluctuations in advance, rather than attempting to protect the sensor after damage occurs.
2Ease of manufacture
If the feed pump operates discontinuously to deliver gas, then the pump construction is simplified and cost reduced, but pressure surges are generated that affect the flow sensor
Solution Approach 1:
The buffer volume serves as a mediator between the discontinuous positive-displacement pump and the flow sensor. It smooths out the pressure fluctuations inherent in discontinuous pumping operations, allowing the use of simple, inexpensive pumps without transmitting harmful pressure surges to the sensitive flow sensor.
3Device complexity
If the flow sensor is placed directly in the gas path before the feed pump, then the gas flow measurement is simplified, but the sensor is exposed to pressure surges from external sources and the pump
Solution Approach 1:
The buffer volume and throttle arrangement act as intermediaries that isolate the flow sensor from pressure surges originating from both external sources (through the sniffer opening) and the feed pump. This allows the sensor to be positioned optimally while protecting it from harmful pressure fluctuations.
Solution Approach 2:
The harmful pressure surge elements are extracted or removed from the path between external sources and the flow sensor by positioning the buffer volume and throttle between these sources and the sensor, thereby isolating the sensor from external pressure disturbances.
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 significantly reduces the risk of flow sensor damage, ensuring reliable operation and accurate gas flow measurements by isolating the sensor from harmful pressure fluctuations, allowing for the use of sensitive micromechanical thermal flow sensors without compromising the leak detector's reliability.
Implementation Method 1
By arranging a buffer volume and a throttle between the feed pump and the flow sensor, pressure surges of the feed pump on the way to the flow sensor are dampened and smoothed out
Data Source
Figure 1
AI summary
The invention relates to a leakage seeker (10) having a pre-vacuum feed pump (20), a gas detector (18) and a flow sensor (26). The invention provides for a buffer volume (22) and a restrictor (24) to be arranged between the feed pump (20) and the flow sensor (26). This protects the flow sensor (26) against pressure surges generated by the feed pump.