KSB Aktiengesellschaft, a Germany pump manufacturer, is introducing submersible borehole pumps for water applications with new energy-saving motors up to 150kW.
The drives are permanent magnet excited synchronous motors, and their output per size exceeds that of conventional asynchronous motors.
If comparing motors of the same size, synchronous machines have a markedly higher output and lower heat development.
With efficiencies being much higher, savings and relatively short payback periods compared with asynchronous machines can be realised.
The motors are operated on a frequency inverter, with the adjusted flow rates reducing the frequency of starts and, with that, the load on the winding.
As this optimised operating mode also keeps the frequency of pump starts to a minimum, it decreases wear and extends the pump’s service life.
A mechanical seal prevents the fluid handled from mixing with the fluid in the motor space, which increases the availability of the motor.
The motor’s thrust bearing is water-lubricated and has self-adjusting tilting pads, requires no maintenance, and easily copes with the stresses and strains of continuous operation due to the material combination of stainless steel and hard carbon.
While the pump set is started up, the counter thrust bearing absorbs the axial thrust caused by the hydraulic system of the pump and prevents the impellers from coming into contact with the stage casings.
This design results in a high operating reliability and achieves the long service life customary for submersible borehole pumps, and smooth running is ensured by a dynamically balanced rotor.
The pump sets are available in different material variants to match the application.
For aggressive fluids, pump sets of 8” and larger are available in duplex stainless steel, and both the pumps and the motors are certified for use with drinking water.
Due to their high output, the new synchronous motors can be combined with much larger pumps of between 6” and 14”.
Flow rates of up to 850m3/h can thus be pumped much more efficiently with the UPA type series.
A patented sand separator prevents any abrasive wear in the pump, and the enclosed pump bearings are maintenance-free.
A lift check valve with anti-blockage valve disc increases the pump set's operating reliability and its integrated spring prevents water hammer due to minimum valve closing times.