Unconstrained pneumatic on-off poppet valve driven by piezoelectric actuator

A radically different principle from that of conventional pneumatic valves is presented, whereby a valve is actuated by piezoelectric actuators (PEAs) with a range of vibration modes. This on/off control valve has an unconstrained poppet structure and therefore the assembling procedures become much easier for miniaturized valves. In this paper, a mathematical model of an unconstrained valve´s internal system including the mechanical behavior of PEAs along with air flow dynamics through nozzles is proposed. Also, comparisons between actual characteristic and simulated results of this on-off poppet valve are presented. In practical application, this valve is able to operate at pressure up to 0.5 MPa and has an average flow rate of maximum 27 L/min for orifice with diameter of 0.8 mm. Finally, the valve is tested with different levels of input voltage and frequency to observe its peculiar flow characteristics.