Thorco manufactures pressure, vacuum, and emergency relief valves for bulk storage, beverage, food, pharmaceutical, chemical processing, refining, and atmospheric applications. 1200A Series pressure/vacuum relief valves come in sizes ranging from 2" to 12", and they are constructed from fiberglass, stainless steel, carbon steel, or aluminum materials. These valves can handle pressure ratings to 15 PSIG and vacuum settings to 12 PSIG.

WellMark manufactures diaphragm back pressure valves for Lact unit, treater, and separator applications. These valves can also be used as pressure relief valves.