Valve Installation & Purging Practice
A UHP valve can be contaminated in the last five minutes of installation. Handling, joint assembly, leak checking and purging are what preserve the cleanliness that was built into the part at the factory.
Receiving and handling
Keep valves double-bagged and capped until the moment of installation. Open bags in a clean area, wear clean gloves and never lay a face-seal face on a bench.
Making the joint
Fit a new gasket, align the glands without forcing them, and tighten to the specified torque in stages. Check that the flow arrow and actuation orientation match the P&ID before closing the panel.
Leak check before purge
Pressure-test and helium-check new joints before introducing process gas. Finding a leak after the system is conditioned costs far more than finding it now.
Purge sequencing
Purge with dry inert gas through the process, purge and vent legs in the defined order. On switching panels, prove that the process port is isolated before the purge port opens, and verify the sequence with position feedback.
Dry-down and handover
Continue purging until the specified dew point is reached, then record the result. Hand over leak records, purge records and valve serial numbers with the panel documentation.
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Frequently Asked Questions
Can I reuse a face seal gasket after a leak check?
No. Replace it whenever the joint is opened.
What should be recorded at handover?
Leak test results, purge/dry-down results, valve serial numbers and gasket replacement records.