One-sentence answer: A gas proportional valve handles gas on/off control, proportional regulation, and electrical control at the same time. Sand holes in the valve body, poor contact between the diaphragm and the valve seat, and failure of the isolation between the gas chamber and the electrical chamber can all cause gas leakage or abnormal combustion. Using the CTS Sentinel A28 differential pressure leak detector to compare a master part with the part under test allows micro-leaks to be identified at low pressure, making it suitable for 100% inspection of every piece on gas appliance component production lines.
Gas leakage can cause deflagration and carbon monoxide poisoning. Therefore, the purpose of testing gas proportional valves is not to screen for process defects but to intercept safety issues. Any practice that increases the judgment margin must be premised on not missing a rejection.
Internal casting defects may only become through-going after machining. Micropores along the gas passage are invisible to the naked eye and can only be exposed by pressure testing.
Proportional valves rely on the fit among the diaphragm, valve core, and valve seat to achieve pressure stabilization and regulation. Diaphragm wrinkles, foreign matter indentations, or spring preload deviations can all form leakage paths.
Once the chamber containing the coil, position sensor, and control circuit communicates with the gas chamber, dust and moisture will corrode the electrical components. This is a structural safety design issue.
Sealing locations:
Consequences of leakage: In the closed-valve state, gas continuously seeps out and accumulates in the kitchen or equipment compartment, and may deflagrate upon contact with an ignition source. Long-term micro gas leakage can also cause excessive carbon monoxide and personnel poisoning. If the isolation wall fails, electrical components corrode and fail, and the valve fails when it needs to actuate. This is a safety-related failure mode.
Gas proportional valves are workpieces with small volume, high-reliability judgment requirements, and batch production:
If the same station also needs to handle flow-type testing in the open-valve state, or if multiple test methods need to be connected in series within the same instrument, the multifunctional single-station model I28 can be selected.
Gas cannot be used for testing. Production line air tightness testing uses dry air or nitrogen, which both avoids the accumulation of combustible gas at the testing station and facilitates unified calibration of the instrument and fixture. Gas-related combustion performance and emission verification belong to the scope of complete machine bench testing and are divided differently from 100% inspection on the production line.
Yes, they should be separated. Closed-valve leakage determines whether there is seepage when the valve is closed and directly corresponds to safety risk. Open-valve characteristics involve flow and regulation ratio and belong to performance verification. Use the A28 to create separate test programs for the two types of items. Safety items undergo 100% inspection piece by piece, while performance items are executed according to the specified sampling inspection plan.
Three conditions must be met at the same time: use differential pressure comparison to reduce the interference of temperature drift on readings, use a stable master part as the comparison reference, and perform automatic calibration and self-test on the instrument periodically with the built-in leak standard. Only by incorporating these three things into daily checks and test programs can the judgment of micro-leaks be repeatable.
Sealing testing of gas proportional valves is essentially safety item interception, with the lowest tolerance for misjudgment. The CTS Sentinel A28 uses differential pressure comparison to stably distinguish micro-leaks at low pressure. Combined with custom-formed fixtures, 32 test programs, and built-in leak standard calibration, it meets the requirements for 100% inspection of every piece and traceability on gas appliance component production lines.
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