通用阀门的启、闭方向是如何规定的？

Specialized in the development and production of fluid control valves

Nesfo Valve mainly develops and manufactures：ball valves, butterfly valves, gate valves, globe valves, check valves, filters, water control valves, safety valves, pressure reducing valves, respiratory valves, regulating valves, pneumatic valves, electric valves and so on.

Address：No.195, Luncang Avenue, Luncang Town, Nan'an City, Fujian Province, China.

Phone：+86-13382208259

Email：nesfovalve@163.com