Active and monitor pressure regulator: how they work together in a natural gas station

In critical installations, two regulators are often used in series: the active and the monitor. The goal is to provide redundant pressure control.

Active regulator

This is the regulator that normally maintains the outlet pressure at the desired value.

Monitor regulator

During normal operation, it remains essentially inactive. If the active regulator fails to control the pressure correctly, the monitor takes over.

Setpoints coordination

The two regulators must have the correct setting differential so that they do not interfere with each other simultaneously.

Relationship with safety systems

The monitor does not necessarily replace a slam-shut or relief valve. All setpoints must form a correct protection sequence.