Valve Assembly Leakage Detection Using Mass Flow Sensor
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Solution Overview
Problem
Existing valve assembly diagnostic systems fail to accurately detect rapid changes in gas flow rates and do not effectively combine accurate flow measurements with reliable valve diagnosis, particularly in gas-fired installations, leading to potential unavailability of combustible gas during start-up operations and risks from excessive input pressure.
Innovation Solution
The integration of a mass flow sensor, capable of wide-range measurements with short response times, is positioned upstream, downstream, or between valve members to detect leakage and input pressure status, with a control unit processing sensor signals to generate diagnostic data and trigger maintenance or lock-out signals based on predefined thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is used to detect gas pressure, then input pressure status can be monitored, but the system cannot accurately detect rapid changes in flow rates or identify small leakages
Solution Approach 1:
The patent replaces traditional pressure sensors with a mass flow sensor that uses thermal principles to directly measure gas flow rate. The mass flow sensor detects rapid changes in flow and small leakages by measuring the thermal effect of gas flow, providing superior measurement precision without requiring complex pressure differential measurements or multiple sensors.
Solution Approach 2:
The patent changes the measurement parameter from pressure (which responds slowly to flow changes) to mass flow rate (which responds rapidly to flow changes). The mass flow sensor measures the thermal energy carried by the gas flow, providing a direct and sensitive measurement of flow rate that can detect even small leakages and rapid transients.
2Reliability
If multiple valve members are used for redundancy, then reliability improves, but the system cannot detect individual valve failures without additional sensors
Solution Approach 1:
The patent implements a feedback mechanism where the mass flow sensor continuously monitors the actual gas flow through the valve assembly. By comparing the measured flow rate with the expected flow rate (based on valve position and pressure differential), the control unit can detect deviations that indicate valve leakage or failure, providing diagnostic information without adding multiple pressure sensors.
Solution Approach 2:
The mass flow sensor acts as an intermediary measurement device that indirectly detects valve performance issues. Instead of directly monitoring each valve member, the sensor measures the overall gas flow and the control unit infers valve status from flow deviations, providing diagnostic capability with a single sensor.
3Reliability
If diagnostic checks are performed by opening and closing valve members, then valve status can be assessed, but start-up operations may be unnecessarily interrupted due to false leakage detection
Solution Approach 1:
The patent uses the dynamic response characteristics of the mass flow sensor to distinguish between transient flow conditions during valve operation and actual leakage. The sensor's ability to rapidly track flow changes allows the control unit to recognize normal transient behavior during start-up and diagnostic checks, avoiding false leakage detections that would interrupt operations.
Solution Approach 2:
The patent performs preliminary diagnostic checks using the mass flow sensor before full operation begins. The control unit executes diagnostic sequences that measure flow characteristics under controlled conditions, establishing a baseline for normal operation. This preliminary diagnosis ensures valves are functioning correctly before committing to extended operation, reducing false interruptions.
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 solution enables precise detection of small and large flow rates, identifying leakages and input pressure anomalies, ensuring reliable valve operation and preventing gas flow disruptions by generating timely maintenance or lock-out signals.
Implementation Method 1
These sensors allow for measurements over a particularly wide range and very short response times of less than 100 ms... A mass flow sensor is arranged upstream of the first valve member (2)... the mass flow sensor (1) acts to detect and to measure a small flow of fluid due to a leakage
Data Source
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AI summary
Valve operation and diagnosis. A method of diagnosis of a valve assembly with valve members (2, 3) serially arranged along a flow channel of the valve assembly, the method comprising the steps of opening all of the serially arranged valve members (2, 3) of the valve assembly, such that fluid may flow through the flow channel connecting at least one inlet and at least one outlet of the valve assembly, of at least one sensor (1) measuring the flow of a fluid through the flow channel, of opening at least one of the valve members (2, 3) of the valve assembly, and of at least one sensor (1) checking for leakage of fluid caused by at least one faulted valve member (2, 3), wherein the at least one sensor is a flow sensor (1), preferably a mass flow sensor (1).