Abstract :
The practical design of electromagnetic pumps is discussed with particular reference to construction of the duct/electrode element. Common features of electrical design are explained in terms of a simple theory of tube efficiency. The scope of d.c. pumps in meeting different duties and practical conditions is indicated. Some results of an experimental investigation of d.c. pump performance in a 4 in-diameter pipe loop are given. The significance of end current loss is indicated, and also the equivalent reduction effected by the presence of a graded fringing field in the end regions. A technique of electrode `wetting¿ suitable for mercury and stainless steel is described, together with gas entrainment experiments. A homopolar generator with mercury collector rings is described. This type of machine would provide an efficient source of current for the d.c. pump. The newer types of rectifier are briefly compared with the generator for this application. Reference is made to polyphase travelling-field pumps, and their appropriate application is discussed. Simple theory of design is given, with relationships for optimum design at standard supply frequency. Other possible designs of large electromagnetic pump are briefly examined and compared with the basic forms of conduction and induction pump. The various classes of pump suitable for laboratory use are mentioned and general principles of selection are offered.
