Valve, Plug 1 : A valve assembly with a plug (straight, tapered, ball, etc.) permanently mounted across the conduit so that when rotated 90 degrees it effects a closure. (Spec 6A)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}