In these days of mega-mergers and emphasis on reducing manufacturing costs, it often seems that getting greater efficiency is all that matters. While this is sometimes true, there are some businesses that rely heavily on high quality rather than quantity. Straub Brewing Company, St. Mary's, PA, is such an establishment.

Its 40 employees manufacture lager beer which it markets within a 120-mile radius area. For 116 years, the Straub brewmasters have continuously gone to great lengths to ensure that each bottle of beer tastes uniformly great. The pure spring water, hops, yeast, and corn flakes combined with careful brewing techniques help ensure that every barrel of beer is bought and enjoyed. Brewery capacity is about 35,000 barrels per year and there's market demand for more, but Straub managers prefer to focus on quality rather than quantity.

At Straub, brewmasters continue to look for ways to improve quality. Any flavor characteristic that can be improved receives attention until better ingredients are found or better techniques are perfected.

For example, one of the challenges is the elimination of trub (a precipitate of grain protein left after boiling) from the yeast, which settles in the bottom of the fermenting tanks. If this trub is left in the yeast, a bitter taste will be noticed in the finished product. Therefore, to alleviate this problem, Straub now uses a Kason VIBROSCREEN circular screen separator.

The VIBROSCREEN operates for about 20 minutes every day, four to five days per week, separating trub from yeast. The liquid yeast is recycled into the next batch. "The VIBROSCREEN has worked very well," reports James Haberberger, plant manager and assistant brewmaster. "We've noticed a marked improvement in the flavor, and we've seen a positive response from our customers." One of the reasons the VIBROSCREEN operates well is because of the multi-plane motion.

The VIBROSCREEN's multi-plane motion is imparted by a gyrator with a double extension shaft fitted at each end with variable extension weights. The motor is rigidly mounted to the main screen assembly which is supported on a circular base by rugged springs that allow the screen assembly to vibrate freely while completely preventing vibration transmission to the floor supporting the machine. All parts above the spring level, including the motor, are integrated as a rigid structure. The spring isolation from the support base results in a self-balancing system that requires only minimal power and avoids excessive mechanical stress.

Top and bottom eccentric weights of VIBROSCREEN separators are independently variable for mass and angular relationship, giving a great degree of control over the complex pattern of vibration. This results in the ability to obtain optimum conditions for screening nearly any material. Adjustments can be made in a few minutes.

The 18-inch diameter VIBROSCREEN is powered by a 1/3 HP gyrator motor. This provides optimum motion at minimal cost for energy. The key element of the gyrator is a heavy-duty bearing designed for vibratory service that gives years of trouble-free service when lubricated regularly with the specified grease.

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Screen Tips - Volume 3, Number 2 July 1988