Flowcon provided the sortation control for the  force feed warehouse in Ft. Worth Texas.  We automatically routed 30-40 boxes per minute to 150 storage queues, then released them in groups for shipping by zones to stores nationwide.

Box separation allows arms to divert boxes as they route through the system. Once scanned, a box's exact location is remembered by the system at all times, until it is released at the shipping dock.

The boxes divert to one of three levels. This calls for extreme accuracy as the divert contact point with the box is typically within one inch, on a line that is moving at 300 feet per minute.  

Each level had a 220' belt, 50 diverters and 50 storage lines. The location of every box was known within 1" by tracking the belt travel with rotational encoders, and by timing box arrivals with photo eyes. Even a slight variation in box strikes could cause a missed divert, or a serious belt jam.

At 40 boxes per minute and up to three minutes to destination, a maximum load scenario requires perfect tracking of up to 120 boxes  at any moment in time. The system was also able to handle the worst case scenario -- 153 diverts at the same time. 

The control system functioned as designed for many years. As seen in this picture, the ceiling height excessively limited the amount of slope on the queues, and thus boxes did not always release without manual intervention, which became a human liability issue.

Boxes in the queues were released to these three takeaway belts, and automatically grouped by zipcode to reduce postal rates. Boxes were conveyed to the shipping dock, where they were staged and loaded into semi-trailers.

The control room is in the middle-left of this picture. The Radio Shack computer displayed all activity on three screens, one per level.

A high speed data cable allowed for micro-second response times. There were 276 AC input relays, and 392 AC outputs for a total AC relay count of 668. Additional high-speed DC relays in the control room, tracked the four encoded belts, plus there were a few analog controls for special functions.

All box movement was dynamically displayed on the screen for the level it occupied. Operators could search and display shipment locations. Sorting and staging were run as two separate functions, and ran independently of each other from the same computer and same keyboard.