MATERIALS HANDLING
other pump manufacturers normally have elastomer lobes rotating in a metal housing and exposed to a high dynamic load, this unit uses steel rotary lobes while the inside of the pump is lined with a rubber insert. Tis is prevented on Tornado T2 pumps via the innovative materials mix: the lobes are made from a particularly robust hardened steel and are not affected by the rotating motion, which clearly increases their service life. In addition, the metal is subject to less deformation under changing temperatures, which means smaller tolerances can be used in production. Tis is reflected in accordingly lower wear and higher efficiency. Te protective housing liner made from
Netzsch replaced an older pump with one of its Tornado T2 pumps
Netzsch therefore suggested to replace the unit with a different operating principle, which had not been available in its product range when the Nemo pump was installed. Te manufacturer now uses the
T.Proc rotary lobe, which is designed to be highly robust and have a long service life. Te “Full Service in Place” design of the pump also minimises the maintenance-related downtimes.
MINIMISED WEAR THROUGH SPECIAL MATERIALS MIX “At the heart of the system are two straight bi-lobe rotors that rotate in opposite directions, moving the medium smoothly but continuously from the inlet to the discharge side,” Grainer says. A characteristic feature of this type of pump is the special material pairing. Whereas
A Nemo pump was used for filling and recirculating ceramic slip until 2013
acrylonitrile butadiene rubber (NBR) can easily be removed as a separate
part and replaced cost-efficiently. Rubber pads vulcanised onto the faces of the metal lobes ensure a continuous hard-soft contact, which also protects components and increases service life. Overall, Netzsch states that this achieves six times longer service life and therefore substantial cost savings for abrasive media.
CONVEYING WITHOUT BLOCKAGE Because the pump action is based on displacement, as in the previously used progressing cavity pump, the viscosity of the medium is irrelevant. Te pump can handle substances from 1 mPas to 1 million mPas. At the same time, pressure fluctuations and shearing forces are excluded: “Tis type of pump does not generate any pressure on the medium, but merely conveys against the existing backpressure – in this case 4 or even
5 bar,” Grainer explains. Te simple shape of the vanes allows a large free ball passage to prevent blockages. Furthermore, this design has a positive influence on the efficiency of the pump. Tanks to the long sealing line, only a very low backflow is generated. Additionally, the specially designed internal geometry of the delivery chamber keeps any pulsation at a very low level, ensuring a gentle, continuous product flow without turbulences. Tis allows the desired properties of the respective slip to be maintained. At the same time, the special housing geometry in connection with the large ball passages additionally minimises wear.
Te rotary lobes are attached outside of the housing with quick-release elements. As a result, they are completely smooth, have no surfaces for deposits and can also be removed and reinstalled conveniently and independently of each other. Tey can be released or tightened with just a few steps, without special tools. A positioning and installation gauge integrated into the front cover makes correct positioning easier in this process. Te shaft seals are also designed so their glide surfaces seal flush against the rear side of the lobes. Tis prevents dead spaces where abrasive particle residue could adhere. Te seals are preconfigured and easily slide onto the shaft with the rotary lobes during assembly. Tanks to the cartridge design, different types of seals fit into the same installation space to suit changing requirements. “For pumping slip, the shaft seal is especially designed as an I-seal with quench. Te silicon-carbide glide surfaces are highly robust and durable, even with this highly abrasive medium,” Grainer explains.
GENTLE DRIVE WITH DOUBLE BENEFIT Te innovative drive concept of the range is also characterised by a long service life
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