Zero Regulator : A gas pressure regulator that operates at an outlet pressure of zero or near-zero gauge or (atmospheric) pressure, usually in conjunction with an air-gas proportioning device
Ministry of Business, Innovation and Employment, Glossary of terms and acronyms, Wellington, New Zealand 2010. http://wwwsosh.govt.nz/resources/glossary-u.shtml, (Occupn Hlth and Sfty - Brit) {530}