Draeger ORMC. Pressure from the oxygen control valve pushes the oxygen diaphragm to the left, opening the nitrous oxide slave valve, which allows a proportionate flow of nitrous oxide to its flowmeter. The slave valve is spring loaded and allows proportionate flow of nitrous or closes completely of oxygen pressure is lost. Source: Fail-Safe Systems, Anesthesia Equipment Simplified Citation: Rose G, McLarney J. Anesthesia Equipment Simplified; 2014 Available at: https://accessanesthesiology.mhmedical.com/DownloadImage.aspx?image=/data/Books/871/Rose001_Fig_11-03.gif&sec=51860867&BookID=871&ChapterSecID=51860175&imagename= Accessed: October 13, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved