Working principle of electromagnetic pump

1. Presented by: Farooq Ahmad Shah

2. Introduction
• Liquid metal are conductors.
• Based on the Fleming’s Left Hand Rule.
• Current flowing vertically through the liquid metal experiences a force (F = I L x B)
along the tube as shown.

3. Types of EM Pumps
• Conduction pump - current is directly conducted into the fluid through
electrodes. Two variants, A.C & D.C.
• Induction pump - current in the conducting fluid is induced by a traveling
magnetic field.
• Thermoelectric pump - current flowing through the liquid metal is derived
directly from the thermal power contained in the hot liquid-metal flow.
D.C conduction pump
Induction pump Thermoelectric pump

4. Applications
Two main applications:
• Cooling of nuclear reactor.
• Pouring and transportation of high temperature metals in foundry.
Image of EM pump used in nuclear reactor Assembled EM pump for foundry
(Courtesy CMI Novacast Inc.)(Courtesy Handbook of Nuclear Engineering by
Daniel Gabriel.)

5. EM Pump from Inside
The electrical current is induced by transformer
action. The transformer's primary coil T in Figure
is connected to an AC single-phase power
source. The transformer pole pieces are
arranged in the shape of a picture frame and
serve as the carrier of magnetic flux. The
transformer secondary winding S around the
bottom leg of the picture frame is molten metal
and is formed by channels in ceramic parts. The
shape forms a single turn shorted winding. The
turns ratio amplifies the electrical input current
to produce very high amperage I in the molten
metal.
Courtesy CMI Novacast Inc.

6. EM Pump from Inside (continued)
A sectioned view of the electromagnet
construction is added, which consists of a C-
shaped pole piece and two excitation coils. The
opening in the C straddles the necked-down
section of the molten secondary turn, so the
magnetic field H crossing the pole gap is
perpendicular to the secondary current I,
resulting in force Q to move metal through the
pump.
Courtesy CMI Novacast Inc.

7. EM Pump from Inside (continued)
This is the complete pump. It is surrounded by or
encapsulated in ceramic parts to protect it from
molten metal contact. Pump output Q is varied
by controlling input power and can be regulated
from almost drop-wise flow up to full bore
delivery.
Courtesy CMI Novacast Inc.
Low pressure
side fill

8. Advantages & Limitations
Advantages:
• No moving parts, no vibrations or wear and tear.
• No seals, no spills.
• Less maintenance and more reliable.
Limitations:
• Power losses due to back EMF, Ohmic heating.
• Limited uses since very few liquids are good conductors of electricity.