Experimental investigation on performance of disposable micropump with retrofit piezo stack actuator for biomedical application

Extensive researches are being conducted to develop miniaturized pumping systems to fulfill the need for accurate delivery of fluids at required rates, particularly in the biomedical field. This paper presents the design, fabrication, and testing of novel valveless micropump actuated through an amplified piezo actuator. The proposed model of the micropump pump has the unique feature of a disposable chamber and employs low-cost polymeric materials, conventional molding and machining operations for fabrication. The disposable part of the pump consists of a laser-cut pump chamber with nozzle/diffuser made of Polymethyl methacrylate (PMMA) and conventionally molded silicone rubber diaphragm. The retrofit part includes the amplified piezo actuator and support structures build from PMMA. Systematic characterization of the pump was carried with water and blood mimicking fluid to understand the effect of operating parameters such as driving frequency and actuation voltage on flow rate and back pressure of the micropump. Experimental results show that the proposed design was capable of pumping 3.3-3.4 ml/min of dye solution and 1.7-1.75 ml/min of blood mimicking fluid at a driving frequency of 5 Hz and actuation voltage of 150 V. The corresponding computed volume resolution/stroke of the pump was found to about 5.75 mu l and 11.25 mu l of blood mimicking fluid and dye solution, respectively. The proposed pump was found to work effectively against a maximum back pressure of 156 Pa with blood mimicking fluid and 250 Pa with the dye solution as the working fluid under the same operating condition of 5 Hz and 150 V.