Linear actuator for a submersible water pump for use in boreholes

Abstract

Both the theory and the test results show that the E-core electromagnet linear actuator, which is based on the variable reluctance principle, can generate a normal force in excess of 400kNm(^-2) when there is a flux density of IT within the airgap. When the actuator is used as a driver in a submersible water pump for use in boreholes the results show that the pump is capable of pumping up to 90% of the expected value. Pressures in excess of 10 Bar have been achieved, whilst the pump was operating at frequencies up to 30Hz. The flow rate was less than 0.21s ', however improvements to the pumping system are given, and the desired 1ls ' flow rate is achievable at a delivery head of 100m.The use of linear actuators for use in submersible water pumps is a relatively new technology, and as the demand for safe clean water increases, it provides for sustainable development. The actuator utilises a D C. supply with solar panels as the source, giving the potential for global use, particularly in developing countries (the South).The design of the driver can be optimised for selected parameters. However, the development of such drivers does have limitations, the overall diameter of the pump is restricted to that of the bore-hole size, 4 or 6 inches; further the length of the pump is dictated by the straightness of the bore-hole. Consequently, design tools, for the design of E-core Variable Reluctance Linear Actuators, (VRLA), are given.