Drill Pipe Safety Valve 1 : A full opening valve with threads that match the drill pipe that can be quickly screwed onto the pipe to help control fluid flow up the tubing
George E. King Engineering, 5000 Oilfield Terms: A Glossary of Petroleum Engineering Terms, Abbreviations and Acronyms, US 2010. http://gekengineering.com/Downloads/Free_Downloads /Glossary_of_Petroleum_Engineering_Terms_25_August _2010.pdf, (Oil - Amer) {593}