Automatic gas distribution stations
DESCRIPTION
Reduction of the gas pressure is performed in order to adjust the natural gas pressure at the outlet to the set value. One of the typical solutions is to create two reduced flows (with a flow rate of 2x100%) with two regulators in each: one is the main regulator, and the other is used as a high-speed valve. The active and control pressure regulators must have a top notch for urgent repairs and maintenance. The active regulator usually keeps the reduced pressure at the set value.
To ensure continuity of the gas supply in the event of a malfunction on the active regulator, the second regulator (control) is installed in series. The control regulator is usually fully open. If the outlet pressure exceeds the permissible limits, the control regulator must operate as a control valve. In normal operation, depending on the maintenance schedule, one line is engaged, while the other line is in the ready state. It starts to operate only in the case when the control and main controller fail. If the outlet pressure exceeds the permissible value, the high-speed device protects the equipment installed behind the pressure regulators in the direction of flow.
To prevent the high-speed device from shutting down in the event of an accident, a spring-loaded safety valve is installed to eject a relatively small amount of gas.