ALL IN ONE TYPE FLUID FLOW SERVO SYSTEM USING SOLENOID VALVE AND ISOTHERMAL PRESSURE VESSEL

摘要

Abstract-In general, it tends to become a complex and expensive structure in the controlling of flow rate. In this paper, a simple structure and compact flow rate servo system is shown. It is easy to carry by integrating needed element, that is, the solenoid valve, the isothermal pressure vessel, the pressure sensor and one board controller of on-off method, although, the external compressor is needed. The signal measured with the pressure sensor is sent to the controller, and the proper control signal is feedback to the switching transistor according to on-off timing of the solenoid valve. In this method, the small pressure fluctuation caused by switching action of solenoid valve can not be avoided, however, this pressure fluctuation enables to examine the actual output flow rate by on-line sampling the pressure and calculation using micro processor on controller. So we execute continuous flow rate control by this compact system alone, and are able to change the output flow rate freely according to manual set up or external control signal. For the evaluation of this system, the blowing up device is adopted to confirm the accuracy of flow rate that is constantly controlled ball height apart from seat.