KWS Manufacturing

Heavy Duty Grit Classifier for New Roofing Shingle Plant

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Plant Location

CertainTeed Corporation
Jonesburg, MO

General Description

The CertainTeed Corporation, a subsidiary of Saint-Gobain, is one of the largest manufacturers of building products in North America. Demand for CertainTeed products continues to grow so they built a new, state-of-the art asphalt roofing shingle manufacturing facility in Missouri. During the asphalt shingle-making process, water is used to cool the shingle sheets and knock off extra granules of grit (sand, minerals and asphalt). Additionally, there is a wash-down cycle to remove extra grit from the machinery and surrounding area. For this project, KWS provided a special inclined grit classifier. Water and grit is directed to a floor pit where the KWS classifier resides. The grit classifier consists of a large hopper with a screw feeder. The grit settles to the bottom by gravity as the screw feeder slowing removes the grit and delivers it to a container for reuse. The water discharges over a wier and is also reused in the process. CertainTeed and KWS worked together on a very similar project in 2010 for their facility in Ennis, TX.

Design Parameters

  1. Product Type: Grit (Various abrasive granules)
  2. Material Density: 100 Pounds per Cubic Foot
  3. Capacity: 85 Cubic Feet per Hour
  4. Duty: 24 Hours per Day, 7 Days per Week

KWS Advantages

CertainTeed and KWS have worked together successfully for many years. The engineers at CertainTeed have been so impressed with our engineering and manufacturing capabilities that they were excited to get KWS involved in their new plant. KWS carefully studied the specifications and application to develop a long-term and cost-effective solution. KWS and CertainTeed coordinated the plant layout and pit dimensions so the grit classifier fit perfectly without compromising the process or functionality.

Special Features

KWS designed and manufactured a unique grit classifier for this project. The system was designed using Autodesk Inventor to ensure the proper layout of the grit classifier with the building requirements as well as upstream and downstream equipment. The grit classifier fit perfectly in the pit with an allowance for maintenance. The screw feeder was angled to remove the grit from the water and deliver it to a container. Since grit is extremely abrasive, KWS designed the grit classifier to operate at less than 20-rpm. The screw flights were constructed from abrasion-resistant material to improve equipment life. KWS utilized a water-purged flanged gland seal to prevent leakage of the water and grit at the inlet end of the feeder. The volume of the classifier hopper was designed for the flow rate requirements of the application. KWS also provided structural supports for the grit classifier.


"Thank you for designing the classifier so it fit neatly in our layout."

Michael Reed, Principal Engineer – CertainTeed Corporation


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