Type ACE97 Pad-Depad valve is a self-contained, pilot-operated valve that maintains a blanket of inert gas on top of a stored product to protect it from atmospheric contamination. It reduces combustibility, decreases vaporization, controls vapor space pressure during pump-in and pump-out operations, and helps prevent the tank from entering a vacuum condition and collapsing upon itself. Type ACE97 valve provides excellent and accurate pressure control of the vapor space in the tank. Blanketing pressure is kept to a minimum in order to conserve the use of blanketing gas. Pad (tank blanketing) ensures a minimum pressure is maintained in the tank vapor space during normal operation. Depad (vapor recovery) limits tank pressure to a maximum value during normal operation.