FKL Efficiently Pumps Shear Thinning Products

A large American packaged foods company was undergoing a production expansion and turned to Fristam for efficient, easy to clean transfer pumps for its BBQ and other meat and poultry sauces.

Working through a Fristam distributor, the processor shared that the pumps would need to transfer a variety of sauces through a tubular High Temperature Short Time (HTST)¹ system, a key component in food safety, and then to a batch tank. Additionally, the pumps would need to be CIP cleanable with no parts removed and no production loss.

The various sauce applications had flowrates that ranged from 10 to 35 GPM, pressures from 100 to 150 PSI, and temperatures from 100°F to 150°F, with viscosities reported to be 4,000 CPS.

Though each sauce had different properties, Fristam knew the right pump for the processor was Fristam’s gentle product handling, positive displacement, FKL model 75A, with double seals (chrome oxide/silicon carbide/carbon), to handle the abrasive and sticky nature of BBQ sauce.

Once installed, the five FKL 75A pumps transferred all the products efficiently and cleaned up perfectly, with the exception of one sauce that experienced a viscosity issue.

During production, it was discovered this sauce would shear thin² from 4000 CPS to less than 400 CPS when pumped. The dramatic reduction in viscosity created too much slip³ in the pump and resulted in the need to increase the pump’s speed to compensate. However, the pump’s original motor was not designed to operate at the increased rate now required.

One solution would be to install a larger pump to maintain the slower rotational speed. However, since a larger pump was not needed for the majority of the sauces, Fristam recommended instead to change out the FKL 75A’s motor from 7.5 HP to 10 HP with a higher output speed gear reducer⁴. Fristam was confident that this would allow the pump to handle both the high and low viscosities seen in the variety of sauces.

Making this change solved the issue and since the adjustment was made, the processor has reported the pumps are working perfectly on all the sauces, and they are pleased with their output and simple and thorough CIP cleaning. Because of this success, the end user went on to replace two existing competitor PD pumps transferring sucrose and fructose to batch tanks with more Fristam FKL pumps.

Terminology:

1. HTST: a method of heat pasteurization of perishable liquids performed to kill spoilage microorganisms prior to filling containers.

2. Shear thinning liquids: liquids that decrease in viscosity as stress, such as stirring or pumping, increases.

3. Slip: product leakage from the high-pressure outlet side of the pump back to the low-pressure inlet side that reduces volumetric efficiency.

4. Gear reducer: a mechanism by which the energy output of a high-speed motor is redirected to turn another mechanical component at a lower rotational speed and at a higher torque.