Emerson 788 DVC manual Principle of Operation, Equipment Damage

D E C 2012 DANIELTM MODEL 788DVC DIGITAL CONTROL VALVES

1.2Principle of Operation

Operation of the Model 788DVC Digital Control Valve is based on a balanced piston principle. When pressure on both sides of the main valve piston are equal, a spring (located on the top of the piston) acts as a differential force and closed the main valve piston. As pressure against the bottom of the piston increases and exceeds the pressure exerted against the top of the piston, plus the force of the spring, spring tension is overcome and the valve opens. Solenoid pilots are digitally controlled

-full open or full closed - and are used to determine the main valve piston position required for flow control. Reference Figures 2-1, 2-2 and 2-3 for valve opening/closing positions.

EQUIPMENT DAMAGE

Read the entire recommended procedure for all installation operations and maintenance procedures before attempting to install or disassemble the valve. Disassembly of this cylinder assembly is different from previous Daniel Control Valves and requires strict adherence to the procedures outlined in this manual.

Failure to read and comply with these procedures could result in damage to the equipment and

compromise in the integrity of the operation.

1-2 INTRODUCTION