Pneumatic diaphragm valves, Globe type, Single spring & Diaphragm Actuated, Pneumatically Operated, Throttling or OnOff Type Control Valve Accu-Flow Series 87, a Globe type, Double ported, Top & Bottom Guided, Single Spring and Diaphragm actuated, ThrottlingOn-Off Type, Pneumatic Control Valve.The valve is double-seated, semi-balanced offering. It is still commonly used in refineries in applications such as crude or bottoms service. The double ported design has full area and reduced capacity trims both V-ported and contoured symmetric configurations.