Piling it on brings benefits in grading
The task was clear, the implementation was a challenge: from Oss in Holland, Engelsmann got an order for the delivery of a JEL Regula Standard type long-stroke screening machine for grading EPS (expandable polystyrene). The machine ordered by the client, Unipol, would be used to expand an existing system for which Engelsmann had already delivered several machines of the same type in the past. The volume flows for the existing system would be optimized with the use and integration of the new machine along with other renovation work. However, in order to expand the production capacities in time the newly ordered long-stroke screening machine needed to be finished in three months rather than the five months that experience tells us is needed for construction. Thanks to the experience in process technology from earlier efforts in technology and the knowledge from the requirements for the machines which had previously been delivered to Unipol, it was possible to shorten the delivery time accordingly so that the machine could be accepted by the customer on time after internal functional and quality tests.
Geared for a high filtration degree with multiple groups
EPS can be found in many plastic products. Its requirements with regard to the particle sizes required are just as diverse. The JEL Regula Standard was specially designed by Engelsmann for the grading of multiple groups of dry and pourable bulk solids within a single screening process. In this application, the JEL Regula Standard was tailored to Unipol’s requirements with a 17.8 m2 screening surface and equipped with 19 screening decks in order to be able to grade up to three groups on the screening surface during operation. A momentum drive based on mass compensation ensures a continuous screening process with movement of the product effected horizontally to the screening deck. Since screening is done from fine to coarse, the screening machine is fitted from top to bottom with sieve inserts which get progressively larger. As a result, the oversized particles are carried through to the end of the screen material and thus serve as a screening aid. During the screening process, the flow of product can be controlled using an externally adjustable distribution plate in order to load all screening decks evenly. It is therefore not necessary to stop the machine or the system. The adjustable sieve angle in combination with the product distribution sheets used and a continuous delivery rate to the sieve thanks to an integrated sieve cleaning system guarantees extremely selective grading with a filtration degree of 98%. For this, the sieve surfaces are constantly cleaned as the impact knocking balls in the cleaning system are thrown against the material of the screen by the horizontal stroke movements of the machine in order to keep the mesh material permeable.
High productivity with minimal downtimes and low energy consumption
Alongside the high reliability and long running times of the Regula Standard screening machine, Unipol made its decision in particular because of the low space requirement for the Engelsmann solution which, thanks to the compact construction with the base frame and the integrated screen stack with screening decks arranged one on top of another, has a small footprint and can thus be integrated into the systems which already exist on site without complex conversion work. Thanks to its dust-tight construction, the Regula brand EPS screening machine not only does its work with particularly low vibration and noise levels (75-78 dBA), but also works dust-free. Driven by an electric motor which delivers its power using a V-belt on an oscillating weight, it is tuned exactly to the mass of the sieve basket. The mass compensation largely prevents vibrations emanating from the machine and also ensures a low energy consumption of just 3.5 kW for a 17.8 m² screening surface.
A lifting device driven by an electric motor makes changing the screen on the JEL Regula Standard as easy as on a single-deck screening machine, even with multiple groups. It is thus possible to dock to any screen frame and lift the screening deck above, and remove and change the sieve insert without needing to remove additional frames. The short downtimes for changing the screens and for cleaning in turn ensure a long running time for the machine and thus high productivity during operation.
The JEL Regula Standard grading screening machine can be equipped with up to 22 screening decks and a max. screening surface of 20 m² for the grading of up to eight groups in a single screening process, and the ATEX version can also be used in areas with a risk of explosion.