What are the nominal pressure, as well as the actual pressure and temperature that a soft-sealed ball valve can withstand?
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This post was last edited by MacDon on 2020-7-8 at 15:43. Soft-sealed ball valves generally use PTFE seat rings. Or a few PPLs or things like Peek. I would like to ask if soft-sealed ball valves are generally available in 300LB and above PN25? Is it much? (Above 150°) I’ve encountered quite a few users for whom the actual pressure before the valve is not high at all – values of around 10–15 kg, or even less – yet they still specify 300 LB (with temperatures that aren’t high either). I don’t know why I also want to ask, what maximum pressure in front of the valve can a regular soft-sealed ball valve withstand? Should we focus mainly on the pressure value before the valve, or on the pressure difference between before and after the valve? If it exceeds that value, does one have to choose a hard seal? What is the lowest temperature that a PTFE soft-sealed ball valve can withstand? Just found out: The TFM valve seat can withstand temperatures down to -40°, while enhanced PTFE can only handle -10°. Are there any other materials that can be used for soft valve seats and withstand low temperatures?
Why choose 300LB when 150LB would suffice: The entire process pipeline is designed for 300LB, and even if the pressure of the medium acting on that valve is 150LB, consistency reasons lead to the use of a nominal pressure of 300LB.
In simple terms, PEEK is used in high-temperature and high-pressure environments, while TFM1600 or TFM4215 is used at low temperatures (-50°C). PCTFE is suitable for extremely low temperatures (-196°C). PTFE can be used at normal temperatures up to PN100; it is not recommended for use below zero degrees (only for imported gaskets)
Hello, what is the maximum temperature at which PEEK can generally be used for a long time?
For ball valves, the PEEK standard allows temperatures up to 280 degrees; however, we generally recommend to our customers that PEEK gaskets can be used over the long term at temperatures below 260 degrees, as higher torques can affect them
I see that the carbon fiber-reinforced PTFE Type C can handle temperatures up to 250°, while the molybdenum disulfide-reinforced PTFE Type F can handle 230°; PPL can also reach 230°. What does PPL belong to?
Type C: 250 degrees is the limit. It depends on the frequency of use by the customer. I’ve never heard of Type F and don’t know anything about it (it’s probably TFM1600). Domestic PPL models – the operating temperature, pressure, and frequency of use all play an important role; these factors need to be taken into consideration together