Theory and Experimental Verification on Cymbal-shaped Slotted Valve Piezoelectric Pump

Chinese Journal of Mechanical Engineering, Feb 2018

Valve piezoelectric pumps usually have larger flow rate than that of valveless ones. However, the traditional cantilever valve easily induces stress concentration which impacts the reliability of pumps. Therefore, a cymbal-shaped slotted check valve is proposed to be applied in a piezoelectric pump in order to reduce the stress concentration of the valve and thus improve the reliability of the piezoelectric pump. The structure and working principle of the piezoelectric pump are analyzed; the stress analysis of the cymbal-shaped slotted valve diaphragm is conducted. In addition, finite element software is employed to analyze the difference of the Von-Mises stress between the cymbal-shaped slotted diaphragm and the slotted flat diaphragm. The simulation results show that, the Von-Mises stress of cymbal-shaped slotted diaphragm is smaller than that of the slotted flat one. Furthermore, the cymbal-shaped slotted valve piezoelectric pump is also fabricated, and flow rate experiment is performed. The experimental results indicate that the flow rate of piezoelectric pump working in low frequencies (0 Hz < f < 50 Hz) is larger than that working in high frequencies (200 Hz < f < 2000 Hz). When driven at voltage of 160 V and frequency of 5 Hz, the pump reaches its maximum flow rate of 6.6 g/min. The experimental results validate the feasibility of the cymbal-shaped slotted check valve. This research can effectively solve the problem of stress concentration of valve piezoelectric pumps and is helpful for improving the reliability of them.

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Theory and Experimental Verification on Cymbal-shaped Slotted Valve Piezoelectric Pump

Huang et al. Chin. J. Mech. Eng. Theory and Experimental Verification on Cymbal-shaped Slotted Valve Piezoelectric Pump Jun Huang 2 Yi‑Chao Zhu 2 Wei‑Dong Shi 2 Jian‑Hui Zhang 0 1 0 College of Mechanical and Electrical Engineering, Guangzhou University , Guangzhou 510006 , China 1 College of Mechanical and Electrical Engineering , Guangzhou Univer‐ sity, Guangzhou 510006 , China 2 National Research Center of Pumps, Jiangsu University , Zhenjiang 212013 , China Valve piezoelectric pumps usually have larger flow rate than that of valveless ones. However, the traditional cantilever valve easily induces stress concentration which impacts the reliability of pumps. Therefore, a cymbal‑ shaped slotted check valve is proposed to be applied in a piezoelectric pump in order to reduce the stress concentration of the valve and thus improve the reliability of the piezoelectric pump. The structure and working principle of the piezoelectric pump are analyzed; the stress analysis of the cymbal‑ shaped slotted valve diaphragm is conducted. In addition, finite element software is employed to analyze the difference of the Von‑ Mises stress between the cymbal‑ shaped slotted diaphragm and the slotted flat diaphragm. The simulation results show that, the Von‑ Mises stress of cymbal‑ shaped slotted diaphragm is smaller than that of the slotted flat one. Furthermore, the cymbal‑ shaped slotted valve piezoelectric pump is also fabricated, and flow rate experiment is performed. The experimental results indicate that the flow rate of piezoelectric pump working in low frequencies (0 Hz < f < 50 Hz) is larger than that working in high frequencies (200 Hz < f < 2000 Hz). When driven at voltage of 160 V and frequency of 5 Hz, the pump reaches its maximum flow rate of 6.6 g/min. The experimental results validate the feasibility of the cymbal‑ shaped slotted check valve. This research can effectively solve the problem of stress concentration of valve piezoelectric pumps and is helpful for improving the reliability of them. Cymbal‑ shaped slotted; Piezoelectric pump; Valve; Stress 1 Introduction The high requirements of micro-chemical mixing, biological detection and insulin injection raises new actuation requirements in the diversity of actuation functions and types [ 1–7 ], and the conventional actuators cannot fulfil these requirements efficiently [ 8–11 ]. To meet these requirements, piezoelectric pumps with the merits of rapid response, high energy density, perfect integration, and no electromagnetic interference attracts a large number of researchers [ 12–24 ]. Piezoelectric pumps can be sorted by two types, valveless piezoelectric pumps and valve ones, according to whether they have an internal moving part (valve) or not. Zhang et  al. [ 25 ] proposed a piezoelectric pump with rotatable unsymmetrical slopes which could be used to piezoelectric liquid mixing and delivery together or separately. Yang et  al. [ 26 ] designed a bidirectional valveless piezoelectric micropump with double chambers. This pump has better performance at low Reynolds number and can change the flow direction by regulating the voltage. Compared with valveless piezoelectric pump, valve piezoelectric pump has a larger flow rate and a smaller pulsation, so it has a more extensive application prospect. Hwang et  al. [ 27 ] designed a reciprocating piezoelectric pump which is used for fuel cells. This pump has the characteristics of compact structure, low energy consumption and even steady output in low driving frequencies. Liu et al. [ 28 ] proposed a PZT-based valve piezoelectric pump, and further designed an insulin delivery system in 2014. This piezoelectric pump, with two pump chambers and three passive valves, can achieve a precise supply of drugs by adjusting the voltage and frequency. Wang et al. [ 29 ] proposed a piezoelectric pump having a compressible chamber and the valve fixed at its two ends for a fuel cell system in 2014. Due to the fixed passive valve, this pump has a lower leakage and a good output performance working in high frequencies. Ma et al. [ 30 ] put forward a separable piezoelectric pump suitable for drug delivery. Due to the separable design between the driving part and the drug delivery unit, this pump can effectively avoid the secondary pollution in drug delivery. Cazorla et  al. [ 31 ] fabricated a functional micro-pump made of silicon and PZT thin films with standard MEMS technology. This pump characterizes being driven by low voltage. However, the reciprocating motion in a high frequency with the check valve as the pump’s core component tends to make the valve generate fatigue damage. Especially when the check valve is working in the fluid, it can generate a large stress which may easily lead to stress concentration, thus aggravating the fatigue damage and causing failure of the check valve. As a result of that, the piezoelectric pump will not work properly. Ding et al. [ 32 ] designed a heart-valve-li (...truncated)


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Jun Huang, Yi-Chao Zhu, Wei-Dong Shi, Jian-Hui Zhang. Theory and Experimental Verification on Cymbal-shaped Slotted Valve Piezoelectric Pump, Chinese Journal of Mechanical Engineering, 2018, pp. 2, Volume 31, Issue 1, DOI: 10.1186/s10033-018-0217-6