Pumpkin Cannery

September 10, 1998

Our first Fiber Filter installation is at the Nestle pumpkin cannery in Morton, Illinois. This cannery operates at rates of up to one hundred tons per hour each year during a season that lasts only fifty days (68 days this year due to California weather). During the entire season employees work 12 hour shifts, 7 days a week. The Libby's brand pumpkin is produced for retail sale, while larger containers are canned for institutional customers.

In a pumpkin cannery the pumpkins are first washed. Then the pumpkins are sliced into chunks and conveyed to Wilter cookers (or blanchers). These are stacked screw conveyors, about 20' long, 4 high, heated with steam. In operation each Wilter drains 50 gpm of 5º Bx liquid. This liquid is mostly juice blanched from the pumpkin, along with steam condensate.

There is a faint percentage of fiber in this drain water. Two years ago a rental CP-6 press was used in an effort to capture the material. The operation was marginal because all of the fiber was forced through the screen of the press at anything above a minimal cone air pressure. Nevertheless Nestle purchased a Model VP-12 screw press.

The installation was not acceptable. The press lacked capacity, and too much fiber went through the screen. The 500 gpm (maximum) flow was way too dilute for a screw press.

The situation has been salvaged by substituting a Model FF-12 Fiber Filter for the screw press. The sludge produced is in the desired range of 8% to 9-1/2% solids. It is noteworthy that since the dissolved sugars are 5º Bx, this means that the insoluble fiber solids in the sludge are actually in the range of 3% to 4-1/2%.

The customer has installed a pressure booster pump for use with the cleaning system. This provides 400 psi at the spray nozzles of the Fiber Filter. It was found advisable to spray the fabric sleeves of the Fiber Filter once a shift.

The sludge from the Fiber Filter is pumped back into the flow of good product to be canned. A progressive cavity (Moyno) pump is used to pump the sludge to an FMC finisher.

The fabric sleeves being used have a relatively large rating of 130 microns. This was selected so that grit, which comes embedded in the pumpkin skin, will pass through the screen and into the wastewater flow.

Issue 83