PETpla.net Insider 09 / 2013

PRODUCTS 87 PET planet insider Vol. 14 No. 09/13 www.petpla.net Top gear Kreyenborg GmbH has provided a customised GPE 140/140-03 gear pump, along with a K-SWE-280-4K- 75-V/RS screen changer with a filtration fineness of 40μm and the associated adapter for an extrusion line that will process four tons/h of recycled PET. The pump has a specific volume of 1,482cm/rev, flow rate of 4,000kg/h of recycled PET material, and 11,100Nm driving torque. While separate sup- port carts are normally used for each machine component, a particular customer asked that the two machines should be mounted on a single support cart. Kreyenborg was able to comply with the request by integrating linear guiding on the cart, which stands on fixed castors and can be moved in the direction of the extrusion along floor- mounted rails. This arrangement also made it easy to pull the equipment away from the line for maintenance. Drives for the company’s gear pumps are typically installed horizon- tally, so the pump will be mounted with gears parallel to the cart frame. However, in order to provide enough space for machine operators to make screen changes, a more compact system design was achieved by install- ing the pump on its side and mounting the drive underneath. This particular extrusion line processes a material with a viscosity of 240-290Pas. The self-lubricating gear pumps are sealed by thread shaft seals. The materials to be processed are pseudoplastic and tend to degrade due to the shearing in the slide bear- ing and also in the thread shaft seal. As product viscosity is highly depend- ent on temperature, additional cooling has a positive influence on the sealing effect of the thread shaft seal; for this reason, it was designed with an adjust- able cooling system that removes heat energy from both the seal and the material itself. Cooling can be with either air or demineralised water. Krey- enborg says that, if a shear-sensitive material is to be processed, residence time in the pump should be absolutely minimised and the company conse- quently recommends a type 03 gear pump. The gear pump type 03 was developed several years ago and since then has proven successful through reduced flow channels which reduce residence time. www.kreyenborg.com