Excess-flow valve

ISO 10628-2 / company legend practice

Drawn as

A bow-tie with a spring drawn inside the inlet triangle and a flow arrow above.

Meaning

Closes automatically when flow exceeds a set rate (a line break downstream). Found on instrument connections, LPG and chemical lines. No dedicated component.

Variants

Usually just a check-valve-like symbol tagged EFV
Some legends write "XS" or "EFV" next to a plain bow-tie