Emerson 788 DVC Marine Instruments User Manual


 
DEC 2012 DANIEL MODEL 788DVC DIGITAL CONTROL VALVES
TM
INTRODUCTION1-2
1.2 Principle 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.