Feasibility of using miniaturised electromagnetic actuator in small air pumps
The feasibility of using an electromagnetic actuator as an important part in a portable diaphragm air pump is investigated. The ideal electromagnetic actuator will have capabilities of producing large deflection and high tuneable frequency. These two characteristics make the actuator very attractive for the present application. Much effort has been put into the development of the proposed diaphragm air pump because it is easily integrated into the complex system. The characteristics of the magnetic field of the electromagnetic coils are thoroughly investigated in order to complete the design optimization for the proposed electromagnetic actuator. As the base of the design optimization for the proposed planar and cylindrical coils, the proposed model of magnetic field distribution for a circular current loop is developed. The design optimization for various parameters of planar coils was thoroughly investigated. Approximate approaches to determine the electromagnetic forces are discussed. Models for diaphragm deflection were determined. The fluid model for evaluation of flow rate form the output of diaphragm pump was developed. The feasibility of using nozzle/diffuser elements as components of air pumps is investigated. The geometry of nozzle/diffuser elements was designed and the chamber configuration for the proposed electromagnetic air pump was determined. The proposed air pumps, including the electromagnetic actuator, PDMS (polydimethylsiloxane) diaphragm, and chamber and nozzle/diffuser elements were built. Several experiments were conducted to investigate the performances of the proposed electromagnetic actuator including the deflection of diaphragm and frequency characteristics. The flow rate of the proposed air pump was measured. In conclusion this study supplies solid evidence of achievements using electromagnetic actuators in air pumps.