Automatic Processing Unit Automatic Processing Unit The APU SERIES AUTOMATIC PROCESSING UNIT is designed to pneumatic metering pumps. The APU accepts a linear 4-20 mA signal a process flow meter and operates a pneumatic metering pump operate proportional to the input signal. This is accomplished by the use of a normally closed, 3-way Economic Automation solenoid valve connected to air or gas supply. The APU pulses the 3-way solenoid valve which is connected to the pneumatic pump. The solenoid is cycled “on and off” to operate the pump. As the process signal increases or decreases, the pump cycles in direct proportion. Thereby increasing or decreasing the amount of chemical injected. FEATURES • Explosion Proof Class I, Groups B,C,D Class II, Groups E,F,G Class III CENELEC: EExd IIC, IP66 • Corrosion resistant, powdercoat finish • Provides pulse rate output proportional to a process signal • Reduced chemical usage by operating proportional to the process flow • Compact unit, ideal for offshore and plant installations • Weatherproof Enclosure NEMA 4, 7BCD, 9EFG • Exterior mounting lugs for easy installation PART NUMBER FOR ORDERING Basic Series Power Solenoid Valve QE — Quick Exhaust* ST — Standard NR — Not Required *Quick Exhaust (QE) option is used when maximum number of strokes are required on larger sized