Mainline valve

From GAWDAwiki

A mainline valve is a main supply-line valve located within the facility. If the source valve is accessible from within the facility, a mainline valve is not required.^[1]

Mainline valves are located at strategic points to isolate sections of pipeline. When a mainline valve is closed, the pressurized gas in the tank forces hydraulic fluid into the actuator closing port and rotates the valve spindle by a quarter turn.^[2]

References

1. http://www.medicalgasinfo.com/content/definitions.htm
2. http://gastoday.com.au/news/actuators_for_critical_mainline_natural_gas_valves/004397/