Magnetic Drive Pump

Overview

A magnetic drive pump is a centrifugal pump with no shaft seal at all. In an ordinary pump the shaft must pass through the casing wall, and that crossing, the mechanical seal, is where leaks and failures concentrate. A mag-drive pump removes it: the motor never touches the wet end. Instead the Driver Motor spins the Outer Magnet Drive ring outside the pump, and its magnetic field reaches through a static Containment Shell to grip the Inner Magnet Ring inside, turning the Impeller Assembly without any rotating penetration of the pressure boundary. The fluid is hermetically sealed, which is why these pumps are specified for toxic, flammable, explosive, and high-purity liquids where any leak is unacceptable.

The wetted hydraulics are conventional: the Volute Casing and impeller raise pressure exactly as in a sealed pump. What changes is how torque gets in and how the rotor is supported, on internal Ceramic Bearing Set bearings and a Thrust Assembly rather than on external bearings and a seal.

How it works

The Drive Magnet poles in the outer ring align with the Inner Magnet Ring poles across the gap, so the two magnet sets behave as a solid coupling and turn in lockstep. The Containment Shell sits in that gap as a pressure-tight, non-magnetic can; it carries full system pressure yet lets the field pass, so the only thing separating the live fluid from atmosphere is a one-piece shell with no dynamic seal to wear out.

Because there is no external bearing on the wet side, the inner Inner Rotor Carrier rides on product-lubricated Ceramic Journal Bearing sleeves of silicon carbide, with a Thrust Washer pair taking axial load. The pumped fluid both lubricates and cools these bearings, which is the design's one vulnerability: running the pump dry starves them and can wreck the bearings and overheat the magnets in seconds, so mag-drive pumps are protected against dry running and dead-heading.

A metallic shell also dissipates eddy-current heat induced by the rotating field, so a small bleed of process fluid is circulated past the magnets and bearings to carry that heat away. Get the lubrication and cooling right and the result is a pump that can run for years with literally zero process emissions.