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Switching out pumps solves pet food processor’s dilemma

While the majority (67%) of Americans own a pet, dogs are the nation’s number one furry companion with half of all Americans owning a dog, according to a research study from Mintel.

When a leading U.S. pet food supplier based in Arkansas encountered difficulties with its wet dog food processing line, the company knew it had to act quickly to meet the demand to feed man’s best friend. The processor realized that the sanitary rotary lobe pump it had been using was not well suited to its conveying tasks.

NETZSCH Pumps North America recommended a progressing cavity pump rather than a rotary lobe pump, given the specific demands of the application. After more than 18 months of use, the NETZSCH progressing cavity pump has eliminated the process concerns that had been causing downtime and lost profits.

The manufacturing process at the factory starts with frozen pieces of ground meat. The larger pieces are broken up and transferred to a cooking station via a screw conveyor. At the cooking station, the meat is prepared to specifications, and gravy sauce is added. The meat with gravy emulsion then moves into a dynamic mixer, and from there to the filling and packaging station.

The company had been employing sanitary rotary lobe pumps to transfer the meat emulsion with gravy both from the cooking station to the mixer and from the mixer to the filling and packaging station. These lobe pumps were not able to handle the high pressure clean-in-place (CIP) process that the processor required and made cleaning and sanitation difficult. These problems led to unplanned downtime, high maintenance costs, and loss in production.

Progressing cavity pumps can handle greater pressures, a wide range of viscosities, and the variability of slurries and emulsions. In addition, progressing cavity pumps feature pump performance that is not affected by the variations and changes that occur during the pet food maker’s production and cleaning processes. Progressing cavity pumps also offer a positive sealing effect between the rotor and stator creating distinct cavities, which permits the handling of higher pressure per stage than rotary lobe pumps.

After studying the application, NETZSCH presented NEMO® progressing cavity pumps as the best solution for transferring the meat and gravy emulsion from the cooking station to the mixer, and from the mixer to the filling and packaging station. In addition to solving the problem presented by the high cleaning pressure, the progressing cavity pump also improved the consistency of the emulsion due to its gentle shear characteristics.

NETZSCH delivered NEMO® pumps in all 316 stainless steel polished construction with tri-clamp CIP and discharge connections. The pumps employ a stainless steel washdown motor for ease of cleaning, and were mounted on stainless steel baseplates with wheels and a handlebar for ease of movement.  The open hopper and feed screw of the NEMO pumps provide a smooth entry for the emulsion in the suction housing of the pump and into the conveying elements.

The stator material selected was an elastomer compound, which complies with the FDA Standard 177.2600 Code of Regulations Title 21. This material offers a good balance of thermal properties as well as rheological properties to handle high pressures and enhance the service life of the stators. NEMO pumps are designed to ensure precise interference between the rotor and stator, thereby delivering the maximum possible pressure per stage.

The two-stage NEMO progressing cavity pumps installed at this pet food facility have been operating successfully, easily handling the CIP process. In addition, the pump has the added benefit of handling any pressure surges that may occur during normal operation. The temperature of the emulsion ranges between 37 and 86°F (3 and 30°C), while during the CIP process, the temperature ranges from 140 to 175 °F (60 to 80°C).

Since the pumps greatly reduced unplanned downtime, maintenance costs and production losses, they provide the pet food processor with a lower total cost of ownership and higher line profitability.