A flexible spider coupling from R+W has been installed in an eccentric screw pump application at Vestolit GmbH & Co. KG, a major manufacturer and supplier of PVC raw materials.
The Germany-based Vestolit GmbH & Co. KG operates one of the largest fully integrated PVC production plants in Europe with a capacity of 400,000 tons per year.
Vestolit is a market-leading supplier of raw materials for PVC window profiles and paste PVC for manufacturing floor coverings, tarpaulin fabrics as well as vehicle underbody protection.
The PVC is produced by extruding the output mass using an eccentric screw pump. R+W was given the task of connecting the electric motor with the extruder shaft.
According to the frequency converter protocol, the rated torques of the rotary forces at this location can reach 2,500 Nm. Moreover, there are additional forces, such as those occurring at system start-up, which clearly exceed the transferable torque of the couplings in use today.
This leads to individual components or the entire coupling having to be replaced several times a year.
To the customer, this meant a shorter life expectancy for the entire system and increased production downtimes, coupled with additional costs for maintenance.
The coupling needed to absorb the vibrations caused by production in order to increase the life expectancy of other components such as the bearings.
In addition to a longer service life, the customer also required fast and simple mounting of the coupling, since the drive and load sides of the application cannot be positioned axially without tremendous effort.
Regulatory requirements placed on the chemicals industry also specified an explosion-proof environment. The use of conventional flexible camshaft couplings, which have been widely used in the chemicals industry for decades, cannot meet these new requirements.
R+W was able to provide the customer with an all-in-one solution, the EKH/4500/D, which was a flexible spider coupling for rated torques up to 4,500 Nm.
Installation time of the elastomer coupling is minimised thanks to the semi-monocoque engineering of the clamping hubs which ensures that radial installation in the drive train does not require axial positioning on the drive and load sides.
The electrically isolating elastomer insert is replaced by parts containing additional graphite in the plastic, making the entire coupling system electrically conductive. This also makes it possible to meet regulatory requirements for an explosion-proof environment.
R+W’s product range is available from RR Fisher & Co Ltd .