Helping Ben & Jerry's pack a bigger chunk - production innovations at Ben and Jerry's Homemade Inc

Dairy Foods, Sept, 1993

Pump design keeps product quality up, intact

Chunks may seem a nebulous term outside the ice cream universe, but not at Ben & Jerry's.

"Chunks are Ben & Jerry's claim to fame, and Ben (co-founder Ben Cohen) likes 'em big," says Production Manager Ellen Ladd. "That's why we set process controls for chunk volumes and sizes in every flavor where they go."

Originally, Ben & Jerry's used external circumferential piston pumps to add chunks to its bulk franchise flavors, pints and novelty items. However, as the $100-million firm created new products with fragile fruit and nut add-ins, production line staff witnessed a decline in the size of chunks.

In 1990, when the firm introduced apple pie ice cream to its franchises, quality controllers observed the double-rotor pump chopping up apple chunks. Later, as Ben & Jerry's was developing Peace Pops, a novelty ice cream bar with melted chocolate and nuts on a stick, the pump's gears often mashed nuts into smaller than acceptable pieces. "We use whole nuts for Peace Pops and apple quarters for our apple pie flavor, and our pumps were breaking both materials up," says Ladd.

In addition to causing sub-par apple and chocolate nut chunks, the double-rotor pumps at times were unable to handle pumping pressures and would shut down. This created further processing downtime and delays, and was especially difficult given the overwhelming production demand for Ben & Jerry's products.

Investigating alternatives

Always eager to improve its production process, Ben & Jerry's began exploring positive displacement sanitary pump alternatives. "The unit had to be powerful enough to pump viscous material like our chocolate nut mix and apple quarters, yet gentle enough to deliver them to our holding tanks without chopping them up," says Rick Jenkins, production supervisor.

"We also wanted a pump that would be easy to install, easy to use, and easier to maintain than the double-rotor, double-shaft, double-seal products we were using," he adds.

Ladd and Jenkins unexpectedly discovered the Sine Pump from the Kontro Co., Orange, Mass., at a dairy trade show. Unlike the pumps Ben & Jerry's was using at the time, Sine Pump employs a single sinusoidal rotor and single shaft that transfers liquids compression free with wave-like motions. Sine Pump's suction lift enables it to pump 400 gallons of viscous or chunky materials per minute and the system can absorb up to 150 psi.

USDA-approved for meat, poultry, and dairy products, Sine Pump offered Ben & Jerry's an opportunity to transport liquids without shear, slip, or pulsation. Its spiraling, sinusoidal rotor creates four symmetrical pumping compartments, providing a positive displacement of liquid through the system's liners. A reversible sliding scraper gate ensures that product always moves fluidly through the pump from intake to discharge, providing bidirectional functionality and flexible ease of use.

Programmed with a simple speed dial, Sine Pump utilizes a software system that protects the system's rotor, shaft housing and cover from wear and tear. Software components like the scraper gate, liners and seals, and O-rings are available in a wide range of materials and can be repaired without taking the pump off line. They can also be configured to suit specific customer needs and are significantly less expensive to replace than conventional rotary pump parts. The Sine Pump is lightweight and portable, so it can be easily transported through the production plant and used in a wide range of applications.

The system proves its worth

After weighing Sine Pump's cost and value, Ladd and Jenkins introduced it on the production line to add apples to Ben & Jerry's apple pie ice cream. Once the ice cream mix is frozen to soft-serve specifications, apples in a hopper are then fed into a funnel on the top of the pump, which pushes them into a pipeline where they are mixed with pie crust and paddled into a 300-gallon vat.

"Unlike our former piston pump whose rotors converged on the apples like a pair of gears, the Sine Pump's wave-like motion delivered the apples without breaking them up. We had a lot less downtime, and it was much easier to meet our quality specifications."

Buoyed by these results, Ben & Jerry's has since acquired two additional Sine Pumps, one to add its highly viscous chocolate and nut mixture to Peace Pops and another to pump cream and condensed skim milk from delivery trucks into its 10,000-gallon holding tanks.

"It may be an expense to start, but when you look at what it's done for our chunks and how easy it is to use and maintain, it's certainly worth the cost--and then some," Ladd says.