PD Pump Goes The Distance
Besides being defined as a long distance race, a marathon also is described as: a contest of endurance; a task or action that requires prolonged effort or endurance. The race requires a commitment to training and preparation and an unyielding determination to keep going until the finish line is crossed.
In a sense, the tomato processing season is analogous with a marathon. The grueling 15-week period, July 1 through October 15, begins with a great deal of preparation and equipment maintenance to keep the lines up and running. It is an around-the-clock race to process the perishable tomatoes while they're in optimal condition.
Los Gatos Tomato Products, a grower-owned processing plant nestled in the heart of bountiful Fresno County, California, has been running this race successfully since it was founded in 1991. The facility processes 700,000 - 800,000 tons of tomatoes per season to produce paste. Once packaged in 55-300 gallon containers, the shelf-stable product is shipped to customers for manufacturing ketchup and sauces.
Producing tomato paste is difficult because it is very thick, sticks to everything, and acts like a sponge when compressed. When the paste is squeezed through a positive displacement pump, for example, clear pectin is produced. The challenge is to control the flow of this water-like substance along with the sticky solids.
"Our product is very thick and having the right pump in the right application is important," said Ray Medeiros, general manager.
His pump of choice, Waukesha Cherry-Burrell (WCB) positive displacement pumps, can be found throughout the plant. In 2000, Los Gatos set up a WCB high-capacity 420/520 model alongside a competitive pump in redundant applications as part of a line upgrade. The pumps move product into FMC FoodTech/FranRica flash coolers at a rate of 150 gpm or 250 tons per hour.
Five production seasons later, the WCB pump is the winner hands down in terms of efficiency. The WCB pump has gone the distance every season and has never dropped below the minimum capacity requirement. As each season progresses, the other pump begins to slip and has to be slowed down to 90 gpm or 150 tons per hour.
"Throughput is critical because tomatoes are a perishable crop," Medeiros emphasized. "Getting the crop processed in a timely manner is of the utmost importance. Not only is the quality affected when the line has to be slowed down, the costs are increased dramatically."
Large diameter shafts and a heavy duty bearing frame are examples of design features that give the WCB pump the edge on durability. Further, arc-shaped rotor wings travel in annular-shaped cylinders machined in the pump body. The resulting long sealing path reduces slippage and produces a smooth flow of product without destructive pulses or pressure peaks.
In addition to efficiency superiority, the WCB pump has required only routine maintenance while the competitive pump has had to be rebuilt twice. "The WCB pump has been very reliable with no downtime and minimal wear," said Medeiros. "The support we receive from WCB and FMC FoodTech is as reliable as our pumps. We can count on them to the end."
SOURCE: WCB/FMC FoodTech