Inclined Screw Feeder to Meter Glass Powder for Coating of Water Heater Tanks

Plant Name and Location

A.O. Smith, Protective Coatings Division
Florence, KY

General Description

With a history of more than 130 years, A.O. Smith is one of the world’s leading manufacturers of residential and commercial water heating and purification equipment. A.O. Smith was very pleased with equipment KWS had supplied previously and returned to KWS for a solution to meter flood-fed milled glass powder. The glass powder is used for their Vitra-Shield product in the Protective Coatings Division of A.O. Smith. In the late 1920’s, AO Smith recognized a growing need to develop a method to protect steel products such as oil field pipes, pressure vessels and storage tanks from corrosion. A.O. Smith developed a process for fusing glass to steel and is now a major producer of glass linings. The Florence, KY facility is their key location for the development and production of coatings. An inclined screw feeder was required to meter glass powder used in the production of Vitra-Shield Frits, which are glass coatings that have been formulated for application on steel, cast iron or aluminum substrates. The coatings provide excellent resistance to corrosion and thermal shock.

Design Parameters

Product Type: Milled glass powder (Highly Abrasive and Free Flowing)
Material Density: 80 Pounds per Cubic Foot
Capacity: 450 Cubic Feet per Hour
Duty: 8 Hours per Day, 5 Days per Week

KWS Advantages

A.O. Smith contacted KWS since they were extremely pleased with equipment supplied on a previous project. The Customer needed KWS to design a new inclined screw feeder to fit on an existing structural frame. KWS engineers have extensive experience in designing around existing equipment and constraints. The expertise of our engineers and designers with programs such as Autodesk Inventor 3D is unmatched. The engineering and customer communication throughout the design phase was so seamless that everything fit up perfectly.

Special Features

KWS designed and manufactured an inclined screw feeder with heavy-duty carbon steel construction due to the high abrasiveness of the glass powder. Since the inclined screw feeder was being flood fed from a ball mill, KWS utilized abrasion-resistant flighting with variable pitch to provide an exact feed rate to the downstream equipment. The flighting was continuously welded on both sides of the center pipe of the screw feeder to add rigidity. KWS designed a special inlet transition to accommodate the new inclined screw feeder inlet and to match the discharge of the ball mill. During the design process, KWS modeled the complete system in 3D to accommodate the ball mill and existing support frame. KWS engineers designed an elongated inlet to ensure all material was being fed properly to the screw feeder and to eliminate the chance of bridging. Since the material was being discharged into two separate totes, the screw feeder discharge mated to a two-way Y style diverter valve which was supplied with abrasion-resistant liners for long life. Installation of the inclined screw feeder went smoothly and the installers were easily able to connect the new equipment to the existing equipment.