Sealless, Leak Free, Mag-Drive Pump


A magnetically coupled centrifugal pump which offers the important advantages of sealless design combined with a hermetically sealed liquid end and therefore zero leakage, is a recent addition to the MICHAEL SMITH ENGINEERS range of pumps.

The magnetically driven Dickow NMW Series is ideal for hot oil, or other similar challenging applications, without the need for external cooling. Thanks to its sealless design and leak-free performance, NMW pumps make an important contribution toward improved plant and safety in industrial heating and other similar high temperature applications.

For example, should a leakage of hot oil occur at high temperature as a result of pump failure, it is likely to react with the atmosphere turning into coke or tar. If the vapour pressure at operating temperature is above the atmospheric pressure, the leakage will vaporize. To protect against this risk conventional pumps are usually fitted with double mechanical seals.

Dickow NMW pumps include a containment shell which ensures a hermetically sealed liquid end, without the need for mechanical seals. With 90% of pump failures caused by leaking seals, the advantages of NMW pumps, especially in view of increasingly tough safety and environmental requirements, in addition to the operational benefits of reduced maintenance and less downtime, are well illustrated.

The containment shell is designed as a pressure vessel to separate the pumped liquid from the atmosphere only and is not used as an additional bearing holder, so no dynamic stresses occur. This containment shell is bolted to the bearing housing with a design that enables easy removal of the bearing bracket including the outer magnets and ball bearings, without exposing the pumped liquid to the atmosphere.

The pumps are single stage, volute casing with closed impellers, back-pull out design, with end-suction and top centerline discharge flange. Foot mounted casings are supplied as standard with a centerline mounted design available as an option.

Dickow NMW pumps are capable of handling liquids at temperatures up to 400ºC at capacities up to 600 m3/hr at differential heads up to 60 metres when powered by 1450 motors, while models powered with 2900 motors deliver capacities up to 400 m3/hr with differential heads up to 150 metres. The pumps are offered in a choice of materials to suit the application along with temperature and power monitoring devices and dry-running protection devices.

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