induction pump[in′dək·shən ‚pəmp]
a magnetohydrodynamic pump that conveys an electrically conductive liquid by means of the electromagnetic force that arises because of the interaction between the magnetic field of the inductor and the field of an electric current induced in the medium moving through the pump. Induction pumps are used for liquid alkaline metals at temperatures of 800°–1000°C and higher. The channels of an induction pump are usually made of stainless steel.
The principle of operation of an induction pump is analogous to that of an asynchronous motor, with the liquid conductor substituting for the rotor winding. Induction pumps are classified as spiral or linear, according to design. Linear pumps are made with a flat channel of rectangular cross section (see Figure 1) or a cylindrical channel with an annular cross section. If the channel and inductor shown in Figure 1 were given an annular shape the result would be a diagram of a cylindrical induction pump.
Induction pumps of the spiral type differ from cylindrical pumps mainly in the arrangement of the inductor winding (the turns of the winding are rotated 90° in the horizontal plane) and by the presence of a spiral baffle in the annular channel. Because of this design the rotating magnetic field of the inductor imparts to the liquid a progressive translatory motion along the main axis. Induction pumps operate on three-phase alternating current; their efficiency is on the order of 0.2 (spiral pumps) and 0.5 (large cylindrical pumps). Induction pumps are used to convey liquid metals in nuclear power engineering and metallurgy.