Regarding the operating conditions of fluororubber valve seats

Thank you, floor 2. I was wondering if you could help me with a detailed analysis and introduction? Thank you!

I don’t think using fluororubber for sealing is a good idea. First and foremost, there’s the issue of temperature – the maximum temperature reaches 180 degrees. Although in theory PTFE can withstand such temperatures, in practical conditions its performance isn’t very good at high temperatures. The medium is nitrogen and hydrocarbons, which are non-corrosive, and the pressure isn’t very high either; therefore, I believe a hard seal would be more appropriate

How did it change from being about the 4th floor to perfluorine just like that? The original poster is discussing fluororubber. In terms of temperature requirements, fluororubber can meet them, but conventional fluororubber does not have sufficient low-temperature resistance; it usually becomes hard at around -20°C. For low-temperature embrittlement, it can reach -25°C. Therefore, if rubber sealing performance is required at -29°C, it is recommended not to use conventional fluororubber. Low-temperature fluororubber needs to be used. We don’t have low-temperature fluororubber in our country, but foreign companies do. But the cost is very high; it seems difficult to afford to produce valve seats. If you can afford it, please send me a message; I’ll show you how to find suppliers abroad. If it’s not bearable, I think silicone rubber could be an option. Indeed, nitrogen and hydrocarbons are not corrosive; rubber only requires temperature resistance. It can be considered. I need to confirm the specific parameters; if necessary, you can reply or send a message. I’ll check for you again.

I don’t think fluororubber is a suitable choice. The first issue is temperature: theoretically, fluororubber can withstand temperatures up to 200 degrees Celsius, but in practice it begins to soften at temperatures above 150 degrees Celsius, and its elasticity largely disappears. If it is exposed to such temperatures for a short period of time and then returned to normal temperature, the fluororubber can regain its elasticity completely, with no impact on its functionality. But doing it for a long time is highly undesirable. Secondly, as a valve seat material, it is subjected to certain pressure during use to ensure sealing. At 180 degrees Celsius, fluororubber is not capable of establishing a seat sealing pressure.

The people upstairs have no understanding at all of rubber. Rubber needs to be cross-linked; after cross-linking, it no longer possesses the properties of its raw form. It cannot soften at high temperatures – instead, it becomes harder and more brittle. The failure condition is the appearance of cracks. I know even less about fluororubber; it can maintain its rubber elasticity for a long time at 230°C. The only drawback is its poor performance at low temperatures; even the best fluororubber exhibits a rebound capacity only down to around -30 degrees Celsius.