Food Engineering

Keep on trucking that pomace

January 6, 2008
Adding water aids in carrot pomace pumping, but cattle ranchers won’t pay for excess water in their feed.

The concentric auger in the seepex 35-24BTHE pump is attached to a plate on the drive shaft and not the coupling rod. A urethane liner in the suction hopper of the pump further stabilizes the auger. Source: seepex.

Grimmway Farms is a California-based grower, producer and shipper of carrots, processing 40,000 of California’s 75,000 acres of carrots. On an average day, the year-round carrot operation at Grimmway processes 2.5 miles of fully loaded trucks.

Recently, Grimmway Farms Plant Engineer Dave Roney recognized a need to upgrade a production process. After carrot purée product streams (a by-product of baby carrots) are centrifuged to extract carrot juice, a progressive cavity pump moves the remaining product (called pomace) from the discharge of the decanting centrifuge to overhead hoppers 30 vertical and 300 horizontal feet away, which unload the pomace into trucks for use by area ranchers as cattle feed. 

Progressive cavity pumps use a helical rotor rotating within a double-helical stator to create a series of pressure-tight cavities, in which material is moved from the pump’s inlet to the outlet. Material to be pumped is packed into the cavities by an auger feeder, which pulls the material from the pump’s feed hopper.”

 “The old pump wasn’t designed to produce the pressure required to move the pomace to the truck-loading hoppers,” Roney explained, “and we used to have to add water to decrease the pressure.” The result was a wet and heavy load of pomace that cost more to ship, plus cattle feed that contained too much water.

The former pump used a small eccentric auger and didn’t have the shearing capability to decrease the viscosity enough to force the product into the cavities. In addition, the pump couldn’t develop enough pressure to overcome the friction loss in the decanting centrifuge discharge line. These problems could be solved by adding water to the pump’s hopper; however, since the pomace was coming into the pump from a decanter to remove moisture, adding water only served to complicate the process.

Roney reviewed several options, including adding an external drag conveyor. Based on his past experience with seepex pumps, he elected to purchase a seepex 35-24BTHE open hopper progressive cavity pump. “I had used seepex pumps for similar applications with other plants, and seepex [pumps] have a reputation for handling the toughest applications.”

The new auger feed and progressive cavity pump that Grimmway Farms purchased can create pressures up to 24 bar or 348 psi, which easily produces the 20-30 gpm required to move the pomace. The pump was a good choice for this specific application because its oversized auger rotates concentrically. It imparts higher shearing forces to the carrot pomace, which reduces its viscosity, allows it to be forced into the progressive cavities of the pump and improves volumetric efficiencies. 

According to Roney, the pump installed quickly and has run maintenance-free since its installation in April, moving 21,600 gallons per day.  The pump has eliminated the need to add water, saving money on shipping and producing a drier and more concentrated secondary product, preferred by ranchers. u



For more information:

Mike Dillon, 937-864-7150, sales@seepex.net