Large, Custom Screw Conveyors? No Problem!

There are many screw conveyor manufacturers in North America. Most choose to focus on building a limited number of standard sizes in large quantities. Precision has always had a different approach. We aim to solve problems for our customers. We design and build screw conveyors tailored to the needs and challenges of your specific application. A recently completed project illustrates our approach.

An equipment design and manufacturing firm specializing in the systems for biomass-fired power generation and wood pellets production needed screw conveyors for a greenfield project. Their customer was constructing a new wood pellet production facility in the southeastern US for producing a utility-scale volume of pellets for export. The planned capacity would make the plant one of the largest wood pellet production facilities in the US.

Application

The application dictated that each screw conveyor would receive wood fiber from one or two bins and discharge, through a rotary feeder, to a high-capacity rotary dryer. The screw conveyor design also included a secondary/standby discharge to be used as a short-term bypass in the event of a dryer stoppage.  Each conveyor was equipped with two inlets, two discharges, two inspection doors in the trough covers, spray nozzles, tail shaft proximity sensors to measure rotation, FAG bearings, and Sumitomo drive packages.

Screw Conveyor Requirements

Each conveyor had to handle up to 83 tons per hour of wood fiber at a bulk density of approximately 8 lbs./ft³. 

In order to minimize the potential for material damming against a mid-conveyor hanger bearing, the design called for a 40’ single-span screw.  Flighting was 3/8” thick A36 mild steel for a 40” diameter and 44” pitch.  The backbone of the screw uses 8” Sch80 pipe due to the heavy loading, the single-span design, and the weight of the pipe and flights.  The trough was built in two sections with a bolted-flange connection.

Results

Manufacturing was completed in 63 days from the date of order to date of shipment. The screw conveyors arrived at the plant site on-time on the promised date.

If you have a difficult or custom application that requires a screw conveyor that isn’t off-the-shelf, reach out to our application specialists and tell us about what you’re looking for. We specialize in application-driven solutions.