Food Engineering

Field Reports: Dairy plant masters the mix

April 10, 2003
High-intensity mixer/dissolver is easy to keep clean and requires little maintenance.

Stainless Rotosolver Dispersers require less horsepower and perform a better mixing job for Richfood Dairy. Source: Admix.

Richfood Dairy has a facility in Richmond, VA that turns out a variety of blended milk and other diary products, juices, and fruit drinks. Blending and mixing is an important part of the operation, and Plant Manager Dean Smith was unsatisfied with the performance of the different mixers he had tried over the years. They didn’t do a very good job and they were difficult to clean. On top of that, they needed a lot of maintenance.

When mixing powders there’s always the possibility of introducing foreign matter, Smith explains. These should get picked up by the strainers during CIP, but with conventional mixing equipment they tend to get stuck in the impeller. “You would have to go in and pull the impeller up, and get the strings and the paper and whatever else that had gotten onto that impeller,” says Smith. And with difficult-to-clean mixers, there’s always the possibility that someone doesn’t do a good job of cleaning every time. Then you’re fighting coliform and bacteria counts in your products.

In addition, conventional mixers have seals, and seals can leak, contaminating the product and requiring seal changes.

About four years ago Smith saw a demonstration of the Rotosolver® disperser from Admix, Inc. at an industry trade show. He was impressed by what he saw, and when he got back home to Richmond he contacted Admix’s local rep, M.G. Newell Co. Newell brought a demonstration unit to the Richfood plant and set it up in the blend room. That demonstration convinced Smith, and he bought a 15 hp Model 160RS159, rated for 600-gallon batch sizes. Installation was simple, he says: “I knew what size containers I was going to use, so therefore knew how long I needed the Rotosolver to be, so we just built the mounts on top of the containers, inverted the Rotosolver up and bolted it down, and took off.” The unit now does all the milk products, including chocolates and high-fat items like half-and-half, whipping cream, and coffee cream.

Two years later Richfood added a second Rotosolver, a 7.5 hp Model 132RS133 rated for 400 gallon batches, and put it to work mixing all the juice and drink products.

The Rotosolvers have been an improvement over the previous mixers in a number of ways. They meet 3A dairy standards, require less horsepower than conventional mixers, and do a better mixing job than other types Smith had tried over the years. “With the blender in motion,” says Smith “you’re changing directions four times with the Rotosolver.” The Rotosolver can blend any of the powders that the plant uses, including difficult-to-mix stabilizers. Guar gum, which Richfood uses in making Tampico punch, a non-carbonated fruit drink, tends to present a particular challenge. “That’s got to be the toughest stuff I’ve ever seen to blend,” says Smith. The Rotosolver has no problem with it, he explains. “You can take the Rotosolver and man, it will bust it up just perfect.”

For more information:

Peter Leitner, Admix, Tel. 800-466-2369; E-mail:;