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The valve should be used below 300 psi and 410 F.
For that pressure and this temperature, 100% PTFE is out of limits, since pure PTFE temperature resistance ends at 200dC, and you operate at 210dC.
PTFE expands 10x more than stainless steel when heated at it's max temperature, and as such creep in between spaces and does deform permanently, if it doesn't clog up some of your valve mechanisms.
If you absolutely want to retain PTFE at your specified operational range, then demand to use a 'stansit' seat and seal, it is a 50% PTFE and 50% SS316 mix, and as such has far less creep and far more resistance against deformation, with the added benefit of temperature resistance up to 260dC at 40bar (1bar = 15psi). Stansit has been around since the 1980's and is a true tested material.
The alternative seal material replacing PTFE as inert seat and seal is PEEK. It is harder while also being totally inert, has far better P/T capabilities than PTFE, but costs a bit more.
At this pressure and temperature, I also advise to ask for a trunion mounted ball valve, since if you use a floating ball valve, the proces pressure will push the ball against your PTFE seat, and deform it permanently if you use pure PTFE.
A trunion mounted ball is kept into place on top and bottom of the ball, and the process pressure press the seat against the fixed rotating ball, reducing seat deformation enormously, since the pressure area of a seat is far smaller than a closed floating ball.
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