Ensuring the integrity of a cryogenic ball valve before it enters service is a critical step in maintaining system safety and efficiency. For industries operating at extremely low temperatures, a minor leak can lead to significant operational failures, including pressure loss, product contamination, or safety hazards. Neway Valve implements a multi-stage verification process to confirm the leak-tight performance of its cryogenic ball valves, providing a reliable barrier against failure.
Helium Mass Spectrometry Leak Detection
One of the most sensitive methods employed is helium mass spectrometry leak testing. This procedure involves pressurizing the valve’s internal cavity with helium, a tracer gas with low molecular weight that can identify minute escape paths. Technicians then use a mass spectrometer to scan the valve’s external surfaces, including the stem seals and ball interfaces, for any trace of helium. This technique can detect leak rates as low as 1×10^-9 mbar·L/s, offering a high degree of confidence in the valve’s seal integrity before it encounters cryogenic media.
Liquid Nitrogen Immersion Testing
Following gaseous tests, a cryogenic ball valve often undergoes a more practical performance validation through liquid nitrogen immersion. The assembled valve is cooled to its intended operating temperature by submerging it in a liquid nitrogen bath. Once thermally stabilized, the valve is pressurized with an inert gas. The subsequent observation for any bubble formation from the stem or body seal areas provides a direct visual confirmation of its leak-tight performance under actual cryogenic conditions, simulating the stresses of thermal contraction.
Stem and Seat Sealing Verification
The functionality of the stem seal and the primary seat seal is verified separately. For the stem, the test focuses on external leakage by applying pressure to the open valve and monitoring the stem area. For seat sealing, pressure is applied both upstream and downstream of the closed ball to check for bidirectional shut-off capability. These tests often adhere to international standards such as API 598 or ISO 5208, which define acceptable leakage rates. Neway Valve documents these results, ensuring each cryogenic ball valve meets specified performance thresholds.
The pre-installation validation of a cryogenic ball valve is a non-negotiable phase in pipeline construction. The combination of highly sensitive gaseous testing and practical cryogenic simulation forms a comprehensive assessment protocol. This rigorous approach confirms that the valve will perform its sealing function reliably, safeguarding the entire system’s operational integrity from the moment of commissioning.
