When the change was made, the plant wanted to increase steam production for the shipyard. This meant trash flow to the facility had to increase. However, because of space constraints, the conveyor size couldn’t be increased. This left increasing the conveyor speed as the only practical solution.
The existing conveyor drive was an inline arrangement that included a 60-hp motor, a gear reducer and a cogged belt connection to the conveyor head pulley. Upgrading the inline arrangement to achieve the necessary speed increase would involve larger drive components, larger reducer and chain guards, larger base platform and associated supporting structure, and time for fabrication and installation on the retrofit.
Motion Industries consulted Chris Wood at SEW-Eurodrive, who recommended a right-angle, hollow-shaft, compact gear reducer mounted directly to the conveyor head pulley shaft. “We remanufactured the conveyor head pulley, as opposed to the upper inline drive structure,” explains Wood. “We were able to mount the motor, high-speed coupling and gear reducer on a swing base and then slide the whole assembly onto the head pulley shaft. By shaft mounting the reducer onto the head pulley, a torque arm bracket was the only part that had to be fabricated.”
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Rather than attempting to upsize the existing inline drive arrangement, the direct drive approach Wood suggested proved to be more efficient and saved installation time, which was a big factor in the project. “A shaft-mounted drive was a good solution,” says Rawlings. “The SEW unit was quick and easy to install onto the conveyor head pulley shaft. SEW had a quick ship, easier installation and was able to deliver more quickly than other companies who submitted bids.”
The project team coordinated with the plant’s maintenance organization to make the transition as seamlessly as possible. “The new drive was installed during a scheduled maintenance shutdown and didn’t interfere with normal operations,” says Wood. “Direct driving the conveyor boosted efficiency by 15% to 20%, which meant a 100-hp motor was sufficient to do the job. A more efficient drive arrangement allowed us to use the smaller motor. Maintenance issues and costs associated with the chain drive were also eliminated.”