Bull plugs are heavier than ordinary hex-head plugs and are threaded or beveled to match the end they seal. A tapped bull plug has a small threaded hole in the nose for a gauge, vent or drain. Oilfield and refinery crews use them to cap open-ended valves, which is a standard requirement so a valve opened by mistake does not discharge to atmosphere.
Every open-ended drain valve gets a bull plug before this unit starts up, I'm walking the line this afternoon.
Also heard as
- bullplug
- tapped bull plug
Related terms
Swage
A forged reducing nipple that steps a small bore line down one or more sizes, with threaded, plain or beveled ends.
Bleeder
A small vent or drain valve used to release pressure or fluid, especially between two block valves.
Tee
A T-shaped fitting that splits or joins flow, with a straight run and a side branch.
Nipple
A short length of pipe, threaded or plain on its ends, used to connect two fittings or a valve to a fitting.