Gate valve

ISO 10628-2 (group 21, valves) / PIP PIC001

Drawn as

Two open triangles meeting tip to tip on the pipe (a bow-tie), with nothing in the middle. A handwheel stem (a T on top) is optional.

Meaning

Manual isolation valve, normally fully open or fully closed, not for throttling. On PIP/ISA-style legends the plain bow-tie is the gate valve; on ISO 10628 drawings the plain bow-tie is a generic valve, so check the legend.

Variants

ISO 10628-2: the plain bow-tie means "valve, general"
Filled (black) bow-tie: normally closed
Some legends add a short vertical bar at the tips to mean gate specifically
Size/class appear only in the line number, not in the symbol