Back-pressure regulator

ISA 5.1-2009 (self-actuated regulators) / PIP PIC001

Drawn as

Like the pressure regulator, but the thin sensing line runs from the dome to the pipe upstream of the valve.

Meaning

Holds upstream pressure: it opens as upstream pressure rises. Used on separator gas outlets to flare, pump minimum-flow and seal systems. No dedicated component.

Variants

Some legends write "BPR" beside it
Look at which side the sensing line goes to; that is the controlled side