Leak-free mag-drive centrifugal pumps


New hybrid can feature by Michael Smith Engineers enhances energy-efficiency of leak-free mag-drive centrifugal pumps

Michael Smith Engineers has produced a new range of magnetically coupled centrifugal, vane, turbine and side-channel pump options for magnetically driven pumps.

The company has developed of a rear containment shell now fitted as standard on their CN MAG-M Series of centrifugal process pumps.

This hybrid containment shell combines the reliability and chemical resistance of a standard inner metallic shell with the strength of a carbon fibre outer shell and can be selected for applications with liquids at temperatures up to 200ºC and system pressures up to 50 Bar.

With a choice of either titanium or hastelloy C inner shell, the M Pump Hybrid Containment Shell has played a significant role in enhancing the operational efficiency and competitiveness of these pumps compared to other standard mag-drive pumps.

The operating principle of mag-drive pumps involves a rotating magnetic field which is separated by a stationary metallic barrier which cuts the magnetic field and generates eddy currents that in turn generate heat.

The amount of heat generated depends on the material of the barrier. Hastelloy C and titanium generate less eddy current than stainless steel while non-metallic materials generate minimal losses.

Also, the strength of a magnetic field reduces in proportion to the square of the distance from it, so the closer together the magnets, the more efficient the coupling.

The M Pumps hybrid solution minimises magnetic losses by featuring a very thin barrier in either hastelloy or titanium, with a thin carbon outer shell.

This reduces the amount of heat from eddy currents and the distance between the rotating magnets, so the machine will consume less power.

This enables a smaller motor to be installed compared to a pump with a traditional containment shell.

Close coupled versions are available, reducing possible alignment issues and minimising on-site space requirements.

A choice of chemically resistant wetted materials helps to extend pump life and increase time between servicing are also offered. For critical applications, secondary containment options are available.

The leak-free design makes M Pumps suited to handling toxic, flammable or other dangerous liquids.

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Models are available for handling capacities up to 4000 m3/hr, differential heads up to 220 metres (single stage) and up to 700 metres (multi-stage) with system pressures up to 150 Bar.