chinese东北嫖妓女HD,午夜成人看特AAAA片视频,巨茎挺进李淑芬的体内视频,亚洲高清毛片一区二区

EN
CN

Butterfly Valve

Butterfly valves, also known as flap valves, are regulating valves with a simple structure. They can be used for switching control of low-pressure pipeline media The closing parts (discs) are discs that rotate to open and close the valve.

Valves can be used to control the flow of various types of fluids such as air, water, steam, corrosive media, mud, oil, liquid metals and radioactive media. They are mainly used to cut off and throttle flow in pipelines.