Abstract:

The piezoelectric pump with valve can potentially be applied in many fields such as fine chemicals, MEMS and the biomedical engineering, etc. In order to overcome the shortcomings like complicated structure, low following up, poor cutoff and high cost of valve piezoelectric pump, a new type of valve with elastic fastened helical linear support that has special-shaped cantilever beam structure is designed. The length of spiral arm of the new design is several times longer than the simple cantilever valve. The opening size is bigger than the pump with traditional valve in operation. In addition, because of the helical linear elastic structure, the valve body can not only be returned from both up and down but also be centered from both left and right. It can be installed in the pump cavity piezoelectric pump with valve. The operating principal of the piezoelectric pump with valve of helical linear shape is developed based on extensive analysis of its advantages and shortcomings. The relationship between piezoelectric driving (voltage, frequency) and the pump flow (flow rate, pressure difference) is established considering the energy delivering route in the pump. Finally the sample machine is built with performance testing carried out. The testing results of pump function for the piezoelectric pump with valve of helical linear shape is consistent with theoretical analysis. The testing result shows that as the driving voltage increases, the output flow and the differential pressure tend to rise. The results are in agreement with the trend of numerical simulation calculation in Matlab. At 220 V voltage 30 Hz, the simulation flow is 41.26 mL/min while and the field testing flow is 10.2 mL/min. The deviation is 75.3%. At 220 V voltage 20 Hz, the simulation flow is 27.51 mL/min while the field testing flow is 22.8 mL/min. The deviation is 17.2%.

Key words: cantilever valve, piezoelectric pump with valve, piezoelectric pump