How to choose the sealing material and method for pneumatic on-off valves with alternating hot and cold conditions
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The sealing materials and methods to be chosen for pneumatic on-off valves operating in conditions of alternating hot and cold temperatures – where the medium temperature ranges from 30 to 180 degrees Celsius – depend on whether there is internal leakage or external leakage
Polytetrafluoroethylene can withstand alternating hot and cold conditions. It is recommended to consult valve manufacturers, as they have extensive experience in this area.
After using tetrafluoroethylene for a year, internal leakage began
Hello, original poster – was the issue of alternating hot and cold conditions resolved later on? For your operating conditions, with a minimum temperature of 30°C and a maximum of 180°C, modified PTFE can be used – the type that is resistant to high temperatures and pressures – for valve seat sealing and shaft sealing. It can effectively solve internal leakage caused by alternating hot and cold conditions. Pure tetrafluoroethylene is used in applications with alternating hot and cold conditions; the expanded tetrafluoroethylene seat can be scraped by the ball of the ball valve, causing it to accumulate there and resulting in the ball valve not closing properly, which leads to internal leakage.