VENT PLUG —
(Vent Plug Assembly) – (Safety Vent Plug)
A special pipe plug having a small allen-wrench operated vent valve. These special plugs are located at the bottom of most ball valves, With the line valve closed (and under pressure) the body cavity pressure can be vented thru this small valve to check tightness of seat seals or to make minor repairs, Having vented the body pressure, the vent plug may be re moved to blow out debris and foreign material or to flush the body cavity. On some gate valves the vent plug is installed on the bonnet for the sole purpose of venting the body. Such valves have separate drain valves.
See: «Block and Bleed»; «Drain Plug».