Heavy-Duty Tubular Incline Screw Conveyor to Convey Extremely Abrasive Alumina for Major Recycler

General Description

Aleris International, Inc. is a major producer of rolled and extruded aluminum products and specialty aluminum alloys. Their Wabash, Indiana facility produces high-metallic aluminum concentrates and powders used in the automotive, aircraft and building construction industries. 24 hours a day, trucks deliver scrap aluminum from plants and construction sites to Aleris. In this facility, the material is analyzed, sorted, screened, and processed to create new aluminum products. For this project, Aleris required a heavy duty tubular inclined screw conveyor to transfer crushed alumina from a screener to another conveyor that fed a series of storage bins up near the roof of the plant. KWS worked in tandem with Aleris to develop a solution to satisfy their needs.

Design Parameters

KWS Advantages

This project offered a unique bulk material handling challenge due to the extremely abrasive characteristics of crushed alumina. KWS offered years of experience and expertise in conveying alumina and other extremely abrasive products. Because of the existing plant layout, Aleris required a 54-foot long screw conveyor to transfer crushed alumina from a screener to another conveyor. Aleris had used screw conveyors in the past with very disappointing results. Their previous solutions were poorly designed and a maintenance nightmare. Internal screw conveyor components such as screws, coupling shafts, hanger bearings and trough liners were only lasting a few weeks and adding tremendous amounts of downtime and additional labor costs. Maintenance costs were exceeding $9,000 dollars per month for the original screw conveyor. The original screw conveyor company tried to fix the problems but failed. Aleris contacted KWS to solve their problem. KWS has successfully completed many projects for conveying extremely abrasive products. No other screw conveyor manufacturer has the combination of technical and manufacturing capabilities than KWS. KWS has a large staff of degreed engineers and is ISO 9001-2008 certified to manufacture high quality products. KWS engineers met with Aleris to fully understand their needs, analyze the material and process and determine the dimensional layout of the new screw conveyor. KWS provided complete system drawings for the project. The drawings were reviewed at the Aleris plant, saving weeks of time in the process. All dimensions were verified and questions answered. Utilizing the latest 3D modeling software, KWS provided a new solution showing how the new screw conveyor fit in the building and eliminated any possible interference.

Special Features

The original unit was a 14-inch diameter screw conveyor running about 50-rpm. This conveyor regularly received surges in capacity from the screener and thus operated fully loaded at times. This problem, coupled with the fact that the screw conveyor was running way too fast for such an abrasive product led to significant maintenance issues. KWS engineers recommended a screw conveyor speed of 30-rpm with a trough loading of less than 30-percent. KWS designed an 18-inch diameter screw conveyor operating at 30-rpm to provide a much longer lasting solution. The screw conveyor was designed for worst-case upset conditions. KWS specified and provided a 60-hp gearmotor with 4-15/16-inch diameter shafts to provide high torque. The inlet section of the screw conveyor was designed to reduce the trough loading if the screener delivered a surge of product to the conveyor. For increased wear resistance and component life, KWS engineers designed the screw flights using AR-235 with weld-on overlay hard surfacing. The hanger bearing and coupling shaft had high-strength Stellite sleeves and an automatic lubrication system to keep the hanger bearings purged with grease. The bottoms of the troughs were lined with tough abrasion-resistant Endura plate. The shaft seal at the inlet end was a continual problem for the Customer. KWS designed an air-purged seal to prevent material from leaking out and protect the end bearing. The KWS design team included a robust support structure to bear the weight of the heavy conveyor while also providing a fork truck path in the plant. This project had to fit an extremely tight layout, so KWS laid out the adjoining equipment to make sure there would be no interferences. KWS engineers have the ability and experience to design for heavy duty applications such as this project.