An O-ring seals the relief valve body to the main housing.
用一个O形环密封安全阀阀体与主外壳。
2
The check valves shall be modular and shall seal to the mainvalve body by the use of an O-ring.
这种止回阀应该是模块化的，并且应该采用一个O形环密封在主阀体上。
3
Note: The main spare parts and sealing-ring materials of ball valve series can be designed for Options as per real working conditions and users special reauirements.