Control theory and action description on pressure difference bypass control system
◆ The figure system: electric control valve and corresponding driver that applied to bypass control system, is mainly composed of pressure-difference controller, driver, transformer and manual bypass valve, the pressure-difference controller detects the pressure difference between inlet and return ends, regulate and control on the electric control valve according to testing results, achieve bypass inlet and return water, to keep pressure differential needed. ◆ When the pressure difference between inlet and return water exceeds the set value, differential pressure valve controller outputs signal to energize valve actuator, the valve is gradually opened; When the pressure difference between inlet and return water reaches to the set value, the pressure difference controller has no voltage output, keep the inlet and return water at setting value, maintain the valve to certain position; When the pressure difference between inlet and return water lower than the set value, differential pressure valve controller outputs off signal, the valve is gradually closed, the inlet and return water reach to setting value finally. |
