Materials advances applied to rotary lobe pump
This rotary lobe pump from Netzsch Pumps & Systems of Waldkraiburg, Germany, successfully addresses conveyance challenges because of its several important innovations in rotary lobe pump design, Netzsch says. These include use of hardened-steel lobes running inside an elastomer-lined metal housing and a timing tooth belt to both synchronize and drive the pump’s rotating element.
Rotary lobe pumps routinely handle solids, slurries, pastes and many liquids. They deliver a gentle pumping action that minimizes product degradation and find many industrial uses due to good sanitary qualities, corrosion resistance and clean-in-place and steam-in-place characteristics.
The Tornado T2 generation of rotary lobe pumps “reverses the entire materials concept of conventional rotary lobe pumps,” says Thomas Streubel, president of Exton, Pa.-based Netzsch Pumps North America.
Instead of standard elastomer lobes, the Tornado T2 incorporates metal lobes running inside an elastomer-lined metal housing. The elastomer insert vulcanized onto the flanks of the lobes creates a permanent “hard-soft” contact between the lobes throughout the 360-degree rotation cycle. This precludes high-wear contact between elastomer or metal parts.
The elastomer insert acts as a stator and is subject to considerably less dynamic load and deformation than a traditional rotary lobe pump design, where the elastomer is used as rotor material.
Additionally, the pump drive is radically modified. Complex timing gear is replaced by a robust synchronized gear with belt drive. The danger of transmission damage is greatly reduced, even as weight and required installation space are decreased.
Because the drive requires no lubrication, the possibility of chance oil leaks is eliminated. Finally, a specially developed pulsation-reduction system ensures minimal pulsation or shear forces are generated, despite this straight, bi-lobe rotor design.