Innovative pump design combines technologies

Seal-less pump specialist HMD/Kontro has unveiled a revolutionary new pump design combining the best features from two recognised pump technologies; canned motor pumps and magnet drive pumps

Seal-less pump specialist HMD/Kontro has unveiled a revolutionary new pump design, which is set to become the future standard for process pumping.

MagMax is the unique innovative combination of the best features from two recognised pump technologies; canned motor pumps (CMP's) and magnet drive pumps (MDP's).

This synergy of two technologies provides considerable advances over conventional pump designs in terms of safety, reliability, cost and energy savings.

MagMax blends the motor and containment concept (secondary containment) from the canned motor pump with the efficiency, simplicity and site serviceability of the magnet drive pump.

The resulting canned magnet drive (CMD) pump has been named MagMax.

HMD/Kontro were not content with just combining the two technologies to bring a simplified solution to sealless pumps, the company wanted to bring another first to the industry.

They have achieved this through designing a proprietary range of motors that are considerably more efficient than today's existing solutions.

The compact MagMax rotates at a synchronous speed, unaffected by pump load.

Not only is the higher speed making the motor more efficient but also giving additional head and flow for a given liquid end.

Colin Guppy, general sales manager, Sundyne Europe said: "Our unique MagMax design is by far the best solution for customers requiring safety with performance and cost efficiency.

The Magnet Drive element provides the performance, simplicity, site maintainability and tough reliability, while the canned motor design gives compact size, much improved efficiencies and maximum containment.

There is no other design on the market which offers all these advantages." HMD/Kontro has successfully been producing rugged MDPs since the 1940s, with many of its earliest pumps still in service.

This wealth of experience is incorporated into the MagMax range which together with its single piece silicon carbide bearings gives exceptional reliability and low servicing costs.

An MDP consists of two magnetic rings rotating synchronously with one another, linked by the magnetic field set up between them.

One ring is connected directly to the impeller, the other to the motor shaft.

These rings are separated by a containment shell, or shroud, that forms the pump's pressure boundary.

The simplicity of construction and robustness of the components make the magnet drive a highly reliable machine.

However in the event of damage to the shroud, leakage occurs.

(Although this leakage can be reduced by using a secondary mechanical seal or throttle bush where the motor drive shaft enters the pump housing.) In the conventional CMP design the outer magnet ring is replaced by a motor winding and the inner magnet ring is replaced by a squirrel cage rotor (similar to those used in a standard industrial induction motor).

The motor winding sets up a rotating magnetic field which links with the squirrel cage rotor, through the shroud, in order to develop torque.

A second pressure boundary around the outside of the winding gives rigorous secondary containment in the event of shroud failure.

However, the disadvantage of using a conventional canned motor, compared to a standard motor, is the significantly reduced efficiency and speed due to the design compromise resulting from the inclusion of the shroud between the stator and rotor.

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