Wednesday, June 27, 2012

HYDRO-TRANSPORTING FOOD: Best Practices for Food Processing Pumps

By Dave Young, Northwest regional manager:

Processing plants look for continuous and trouble-free operation from a pump capable of transporting even the most delicate whole food products or processed foods, while keeping product damage to a minimum. This ensures the highest profits for the plant.

Cornell pumps help hydro-transfer systems to clean and convey potatoes, carrots, cranberries, pickles, cherries, beans, peppers, leafy vegetables, crawfish, shrimp, and hatchery fish. As a consumer you encounter food products daily that have been hydro-transported; in fact, most packaged salad producers use food handling pumps to process and transport products, without damage, for the fresh pack industry.

Mechanical conveyors and hydraulic elevators designed to process and transport products have been on the market for years. However, the hydraulic conveyance of food products provided by hydro-transport food handling pumps represents a superior alternative due, to the enhanced economics associated with the simultaneous transport and processing of the product.

The following are suggested steps to take when using and installing a food processing pump for hydro-transfer.

The vortex should be controlled so that air is not drawn into the pump

  • Although the pump capacity required will depend upon the tonnage to be handled, the pump preferably should be selected so that it will operate at its point of peak efficiency or slightly to the left of this point on the characteristic curve. This induces a pre-rotation in the suction eye resulting in reduced product damage on the leading edge of the impeller.
  • The speed of the pump should be selected to meet the head requirements of the system. Heads up to 110 ft. have been successful with some foods. The system should be designed to keep the head as low as possible.
  • The ratio of water to food solids should be as great as is practical or economical. One to three gallons per pound is the general range.
  • A pump with a single port food handling impeller is recommended for most foods. A pump with a bladed impeller can cause damage.
  • Food solids should be carefully separated from the liquid at the dewatering screen as this is a common point of product damage.
  • For new uses, it is recommended that the first pumping unit be installed with a provision for variable speed operation and observation of condition of the product after passing through the pump. There is evidence that short radius elbows, rough pipe joints or beads inside the welded pipe can cause more damage to foods than the pump itself. A velocity in the pipe of 5 feet per second should be tried first, as this velocity appears to be above the critical for movement of food suspensions without clogging. When pumping food with hot water, contact the pump manufacturer for the required minimum suction head to obtain performance comparable with cold water.