Research On Compliant Valve Piezoelectric Pump

Piezoelectric pump has become a substitute for traditional pump in cell transport,chip cooling and other industries due to its advantages of low power consumption,high precision,and has great application value.After more than 30 years of research by scholars at home and abroad,the design and manufacture theory of piezoelectric pump has gradually matured.The piezoelectric pump incorporates the pump chamber,valves and actuator into one unit,which not only eliminates leakage,wear and fatigue damage caused by moving parts,but also reduces the energy loss between different parts in a conventional pump.According to whether there is a moment that the flow channel is completely blocked in a working period,the piezoelectric pump can be divided into valved piezoelectric pump and valveless piezoelectric pump.If there is,it’s valved piezoelectric pump.If not,it’s valveless piezoelectric pump.The valved piezoelectric pump has a high complexity of structure.At the same time,the repeated closure of the valves make the survival rate low during the conveying of active substances,but it can obtain a higher flow rate and pressure difference.The valveless piezoelectric pump has the advantages of simple structure,convenient manufacture,high survival rate of living material transportation,but its flow rate and pressure difference are small.The traditional valved piezoelectric pump and valveless piezoelectric pump only have a single attribute,which will limit the further application of the piezoelectric pump.Aiming at these single attributes,this paper designs a new type of flexible valve piezoelectric pump according to the characteristics of flexible hinge,imitating the structure of venous valve and the characteristics of its opening and closing with the change of heart pressure.As the main functional components of the pump,the flexible valve has a straight circular hinge structure,and imitates the two-valve structure of the vein valve.The flexible valves enable the piezoelectric pump to realize the free conversion between the large pressure difference as well as large flow rate and the low pressure difference as well as small flow rate under the condition of only changing the driving signal of the piezoelectric vibrator.Therefore,the pump can be used for macro and micro combined fluid transport and pressure transfer,and belongs to the macro and micro combined intermediate components.In this paper,the structural design,theoretical analysis,experimental verification and optimization design of the compliant valve piezoelectric pump will be studied.The specific work contents are as follows:(1)Structural design.From the bionic design of the flexible valve structure,including the imitation of the half-month vein valve and the selection of the flexible hinge,and then to the overall structural design of the flexible valve piezoelectric pump,including the overall layout of the principle prototype,the connection relationship of each spare parts and sealing.(2)Theoretical analysis.According to the working principle of the flexible valve piezoelectric pump,the mechanical model of the flexible valve was established and the force analysis was carried out.It was proved theoretically that the opening and closing degree of the flexible valve can be changed by adjusting the input signal,and then the transition between the flexible valve piezoelectric pump in the valved-state and the valveless-state can be controlled.(3)Experimental study.The principle prototype was fabricated by 3D printing technology,laser cutting technology and bonding method.Amplitude test of the piezoelectric vibrator,flow rate test of the pump,pressure test and working state test of the flexible valve were carried out.Through systematic experimental analysis and comparative study,the relationships among voltage,frequency,flow rate and pressure were obtained.The correctness of the theoretical analysis is verified.It is intuitively proved that the flexible valve piezoelectric pump can switch freely between the valvedstate and the valveless-state.(4)Optimized design.The influence of the structure parameters of the flexible valve on the output characteristics of the piezoelectric pump was studied by orthogonal test,so as to optimize the flexible valve structure with better performance of piezoelectric pump.The output performance of the optimized compliant valve piezoelectric pump was tested,and compared with the same type of piezoelectric pump,it was proved that the output performance of the pump has improved.