It is commonly used in soft-sealing butterfly valves for applications where compatibility with water, steam, and various chemicals is required. NBR seals are commonly used in soft-sealing butterfly valves for applications involving oil, fuel, hydraulic fluids, and other petroleum-based products. soft Sealing Butterfly Valve PTFE offers excellent non-stick properties and can withstand a wide range of temperatures and pressures. FEP seals are used in soft-sealing butterfly valves for applications requiring transparency, such as pharmaceutical and food processing industries. These are some of the common materials used to manufacture soft-sealing components in butterfly valves.