In order to improve the output capacity of a piezoelectric pump when transferring gas, this paper presents a compact resonant piezoelectric diaphragm pump (hereinafter referred to as the piezoelectric diaphragm pump), which is driven by a rectangular piezoelectric vibrator. The compact structure can effectively release the vibrating constraints of the vibrator, and enlarge its center output displacement, so as to increase the volume change rate of the pump chamber. Based on the structure and the working principle of this piezoelectric diaphragm pump, a dynamic model for the diaphragm system is established in this paper, and an analysis on factors affecting the resonant frequency of the system is then conducted. We tested on the prototype under the driving voltage of 260 Vpp. The results show that the diaphragm system reaches resonance under the driving frequency of 265 Hz, which is very close to the fundamental frequency of check valve. Compared with the rectangular piezoelectric vibrator’s amplitude, the diaphragm’s amplitude is double amplified. At this time, the piezoelectric diaphragm pump achieves the maximum gas flow rate as 186.8 mL/min and the maximum output pressure as 56.7 kPa.

A piezoelectric vibration feeder with a magnetic spring is discussed in this paper. The feeder can keep resonance frequency relatively stable under changing loading. Through the analysis on the working principle and magnetic spring stiffness characteristic of this feeder, the dynamic model was established and the relationship among system resonance frequency, loading and magnetic spring stiffness was obtained. The analysis showed that, as the loading changed, the magnetic spring stiffness changed accordingly, which maintained a trend of stability in the system resonance frequency. A prototype was made for the experiment, and the relationship among the loading, magnetic spring axial clearance and system resonance frequency was obtained. The result showed that, when the loading changes, the resonance frequency and feeding speed tended to be stable, which matched the theoretical analysis. Through comparison with a traditional vibration feeder, within nominal loading, this new feeder has more stable resonance frequency and feeding speed.