GML/GMB gear pumps combine the Dickow magnet coupling design with Tuthill Globalgear technology. These magnetically driven pumps are designed to improve plant and personnel safety, especially when handling toxic, explosive or dangerous liquids which react on contact with the atmosphere. In combination with explosion proof drive motors, GML/GMB pumps can also be installed in hazardous areas.
Dickow’s GML/GMB pumps offer multiple benefits for the chemical, petrochemical and allied industries, and they also protect the environment. These pumps handle everything from bulk materials, chocolate and asphalt to high-temperature fluids and a wide array of chemicals. Their rugged design with strong, tough materials means they last longer than normal. The rotor and idler gear are built to cope with the stresses of high viscosity operation. The patented lubrication method extends the overall life by reducing friction.
The individual components of the multipolar magnetic coupling are manufactured from cobalt samarium, a permanent magnet material with an unlimited lifetime. The magnets in the driven rotor are completely encapsulated. Power is transmitted to the hermetically sealed liquid end by a bank of external magnets. The inner and outer magnet rings are locked together by magnetic forces and work as a synchronous coupling. The inner ring transmits the required torque directly to the rotor. Overload of the magnetic coupling and slippage do not result in demagnetisation if temperature monitoring is available. If a higher motor power becomes necessary subsequently, the nominal power of the coupling can be increased with additional magnets. The containment shell is designed as a pressurised vessel to separate the pumpage from the atmosphere. It is bolted to the bearing housing in a manner that allows the bearing bracket (GML pumps) or the drive motor (GMB pumps) to be removed together with the drive rotor without draining the pump.
The clearances between the drive rotor and the motor support lantern or between the bearing bracket and the containment shell are arranged such that rubbing of the magnets on the containment shell will be avoided, even in the case of worn out ball bearings.. The internal clearance between the rotor and the containment shell is approximately 1.0 mm. When the pump is in operation, it produces eddy currents which heat up the shell and the pumpage in the magnet area. This heat is dissipated by internal circulation.
Shaft bearings
The pump shaft is carried by wetted sleeve bearings. The standard material used for them is pure silicon carbide with a diamond layer, providing limited dry run capability. SiC is highly resistant to corrosion and wear and can be used for all kind of liquids, even products containing solid matter. The SiC components are shrink-fitted and therefore protected against shock and thermal stress. Both sleeve bearings are bolted in a common housing to ensure correct alignment.
The drive shaft of the GML pumps is supported in generously sized anti-friction bearings with lifelong lubrication and a lip seal as protection against the atmosphere. The drive rotor of GMB pumps is mounted to the motor shaft, so that no additional bearings, elastic coupling or coupling alignment are required.
In combination with explosion proof drive motors, GML/GMB pumps can also be installed in hazardous areas (Group II, Category 2). The containment shell temperature of close coupled pumps (GMB) is limited if an explosion proof motor is used. A connection for a detection element for measuring the containment shell surface temperature is provided as standard. Dry running protection as well as monitoring of the ball bearings and containment shell temperature with the patented MAG-Safe system are highly recommended.
Halle 8.0, Booth D54
cpp-net.com/0215402
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