Heavy Duty Screw Conveyor for Conveying Clinker Cooler Dust Holcim Cement, Three Forks, MT

General Description

Holcim is one of the world’s leading suppliers of cement and aggregates (crushed stone, gravel and sand) as well as ready-mix concrete and asphalt. For almost 100 years, Holcim has provided building materials for roads and buildings throughout the world. Holcim produces over 10 million metric tons of cement and aggregates per year.

At the Holcim plant in Montana, screw conveyors are used to convey various bulk materials for the making of cement. As the bulk materials are reduced in size and ground into powders for mixing, a large amount of dust is generated in the process. The dust is captured in the air pollution control equipment at the plant. Holcim contacted KWS with the request to design a new bag house collection screw conveyor that would convey clinker cooler dust over 30-feet without the use of internal hanger bearings. Holcim wanted to reduce maintenance and improve efficiency with the new screw conveyor design.

Design Parameters

1. Product Type – Clinker Cooler Dust
2. Material Density – 60 to 85 Lbs. per Cubic Foot
3. Conveyor Capacity – 12,000 Lbs per Hour
4. Duty – 24 Hours per Day, 7 Days per Week

KWS Advantages

KWS has developed a good reputation for designing and delivering screw conveyors that exceed the expectations of our Customers. Designing and manufacturing a screw conveyor to span 30-feet without an internal bearing requires engineering expertise and additional manufacturing capabilities. The engineers at KWS designed the conveyor screw to be mounted on large diameter pipe to keep the deflection at mid-span below 3/16-inch. Excessive deflection would cause cyclical loading on the screw and eventual failure. The drive and tail shafts of the screw conveyor were also designed to handle the additional bending loads caused by the weight and length of the long, single-piece screw.

Special Features

KWS has the knowledge and manufacturing capabilities to build a screw mounted on large diameter pipe. Please see the KWS Feature & Benefit titled “Large Diameter Pipe” on our website. Since the screw conveyor was required to meet MSHA requirements, special shaft guards were provided for the drive and tail shafts to keep injuries from occurring. Both ends of the screw conveyor were designed with adjustable flanged gland seals and pedestal trough ends. Flanged gland seals have three rings of replaceable rope packing that can be adjusted as the packing wears. By mounting the bearings and drive unit on pedestals, contamination is eliminated. The screw conveyor was completely dust-tight to prevent leakage of the clinker cooler dust.

Two inspection ports were mounted on top of the conveyor with safety wire mesh inside to allow equipment operators the ability to inspect the screw conveyor during operation to make sure there were no clogs in the system. For additional security, a speed switch was installed near the discharge of the screw conveyor to help the operators monitor operation from the control room.