Development of a piezoelectric micropump with novel separable design for medical applications

An innovative separable piezoelectric micropump has been developed to provide low-cost liquid delivery for medical applications. The actuator of the proposed micropump can be used repeatedly to reduce costs, and the pump chamber is disposable to prevent contamination as well as infection. The micropump was fabricated on a highly accurate CNC machine. A piezoelectric plate measuring 22 × 40 × 0.7 mm was used as the actuator and the operating voltage was AC 50-80 V. Moreover, a unique bossed diaphragm, with a cylindrical protrusion at its center, was designed to not only facilitate contact between the diaphragm and piezoelectric actuator but also to overcome the adhesive force, which is a major challenge facing separable micropumps. According to the results of experiments, the adhesive force caused by residual liquid in the pump chamber may adversely affect the resilience of the diaphragm, leading to an insufficient liquid supply. The results show that the thickness and bossed ratio of the diaphragm have a major effect on the flow profiles. To achieve the optimal performance, a 0.3-mm bossed diaphragm was combined with a pump chamber with a depth of 1 mm. The flow rate of the proposed optimal separable micropump can be modulated from 1.58 to 6.21 ml/min at frequencies of less than 20 Hz, and the pump head can reach a maximum of 200 mm-H2O.