Copper Pellet Leakage Problem Solved Encore Wire Plant in McKinney, Texas

Plant Name and Location

Encore Wire
McKinney, TX

General Description

Encore Wire is a leading manufacturer of residential, commercial and industrial building wire. Started in 1989, Encore Wire has grown from a 68,000 square foot industrial warehouse in McKinney, Texas to over 2 million square feet under roof which stretches across 425 acres today.

Much of the copper used to produce new wire comes from scrap copper in the form of tubing, pipe and old electrical /telecommunications cable after the insulation has been removed. The copper is then chopped into small pellets and conveyed to a melting furnace just before a rod mill. The rod mill produces 8-mm copper rod. Various gauges of copper wire are drawn from this rod.

The small copper pellets are dumped into a large hopper and discharged into a screw feeder which then feeds a bucket elevator that elevates the copper pellets to the melting furnace. Originally, the screw feeder was located in the horizontal position and had been designed to meter the copper pellets from the hopper to the bucket elevator. The original design had worked satisfactorily for over 3 years. In early 2017, the decision was made to change the position of the screw feeder from horizontal to a 40-degree incline to improve layout issues. The only change to the screw feeder at that time was to replace the 1150-RPM motor with an 1800-RPM motor which increased the screw feeder speed from 14-RPM to 23-RPM. The new arrangement worked well for a few days until copper pellets began to leak out of the lower end of the screw feeder causing production and housekeeping issues.

Design Parameters

Product Type – Copper Wire Pellets
Material Density – 353 Lbs. per Cubic Foot
Capacity – 7,000 Lbs. per Hour
Duty – 16 Hours per day, 5 Days per Week

KWS Advantages

A Regional Sales Manager from KWS visited the facility and met with Encore Wire’s Maintenance Manager to determine the source of the product leakage and the exact needs of the plant. While onsite, dimensional information was gathered on the existing equipment to determine solutions which would resolve the issues with the most economical, least invasive solution.

Special Features

KWS modified the existing screw feeder by relocating the drive unit to the discharge end. A pedestal trough end was installed on the inlet end (lower end) with a pillow block bearing. Pedestal trough ends provide an 8-inch space between the trough end and bearing and prevent contamination of the bearing. An adjustable split gland seal was added to the tail end to eliminate the leakage of copper pellets. Split gland seals are easily adjusted and the seal packing is very inexpensive and easy to change out.