Three-dimensional analysis and magnetic shield design for an electromagnetic valve by an FE code

The effect on a proportional electromagnetic valve of a strong external magnetic field orthogonal to the valve´s axis and the optimal design of a magnetic shield are presented in this paper. The valve is used to control the gas flow in a fusion device, and its throughput should not be influenced by the external field. The valve, the shield and the perturbing field are modeled by using a 3-D finite-element code based on the reduced scalar potential formulation. An optimization procedure is applied to minimize the volume of the shield together with the effect of the perturbing field on the force produced by the valve´s magnetic circuit