Control system for valve - prevents hunting by using actual pressure and rate of change of pressure as control parameters

摘要

The control system uses both the magnitude of the pressure and the rate of pressure to control the opening and closing of the valve. This prevents the valve being operated unnecessarily, when the pressure fluctuates, and for eliminating overshoot when the valve is operated. If the valve is designed to open at 165 bar and if the limit above which the valve is controlled by the rate of pressure change is 160 bar, the valve is opened at 161 bar in the presence of pressure gradients above 1 bar/s., but not until 165 bar with pressure gradients less than 1 bar/s has been reached.