Design and performance of piezoelectric pump with active valve actuated by rectangular piezoelectric vibrator

According to the working principle of the piezoelectric pump(PEP),a PEP with an active valve actuated by a rectangular piezoelecltic vibrator(PEV)was developed based on the initial two-end-clamping active value design,and its structure and working principle were described.The theoretical flow rate of the developed PEP was calculated and its affecting factors were discussed.The test result indicated that the optimal phaseshifts between the PEVs in the valve chamber and the pump chamber are 70 ° and 250 °.The output characteristics of PEP when the PEV in the valve chamber was exeited by drive signals with different voltages and frequencies were measured.The two-way pumping capacity of PEP with active valve was analyzed comparatively.The measuring results showed that the square wave as control signal for the active valve with the rectangular PEV results in flow rate higher than that by sinusoidal wave.The maximal flow rate is 140 mL/min at frequency of 70 Hz.Under the high exciting frequencies,the PEP with active valve using the rectangular bimorph keeps better flow rate capability than that using the circular PEV,the flow rate of which decreases significantly with rise of frequency.