Experimental feasibility study of a magnetic elevator for particles

Abstract The paper describes elementary tests of a preliminary laboratory model system intended to circulate particles of magnetic materials in chemical reactors. The system will be referred to as a magnetic elevator for particles and circulates particles without using mechanical or pneumatic means. Such a device is a logical complement to earlier systems which have been developed for the control of particles, namely: a magnetically stabilized bed; a magnetic distributor downcomer; and a magnetic valve for solids. In processes which utilize magnetic particles, such as magnetized-fluidized beds, it is envisaged that a magnetic elevator could be used for circulating the particles, provided that the Curie temperature is not exceeded in the transport lines which form the elevator itself. In addition, magnetic solids which are used in processes operated below such temperatures, and under low or zero gravity conditions, could also be circulated without the need for mechanical or pneumatic subsystems. Two distinct modes of operation were observed during the testing: 1. (i) the catchment mode; 2. (ii) the transportation mode. Methods of analysing and predicting device performance for both modes are suggested. Both transverse and axial flux designs of the MES were tested: more detailed investigations were undertaken on the latter configuration which appears to be the more promising form. A multiple coil laboratory model, with coil sequencing by computer, was constructed and tests were performed on this model to investigate: 1. (i) catchment currents, 2. (ii) energization timing 3. (iii) coil spacing and geometries, 4. (iv) different sizes of particle. The paper provides results from the above tests and gives proposals for control and design improvements to optimize the operation of the elevator.