Researchers at the U.S. Department of Energy's Pacific Northwest National Laboratory (P.O. Box 999, MS K9-09 Richland, WA 99352) have cooked up a new way to help food processors solve some sticky, gooey or lumpy problems. They're adding a little ultrasound to the mix.

Researchers are putting

ultrasound to work on everything from potatoes to pudding. Their laboratory is equipped with an industrial-sized mixer, oven, steam kettle and other standard food processing equipment, all of which are outfitted with ultrasonic sensors. The laboratory contains three flow loops made of plastic piping through which various products can be pumped. Ultrasonic sensors monitor the physical properties of the materials during the pumping process. The activity mimics the material transport operations that take place during the manufacturing of foodstuffs, chemicals and other consumer products. Until now, there had not been a non-invasive technique for determining when a product is uniformly consistent in its composition.

Using ultrasonic equipment, companies can test products non-invasively by placing sensors on the outside of the vessels and piping in a product being mixed or transported. For products flowing through a pipe, researchers have developed a viscosity meter based on ultrasonic Doppler measurements. The lab's ultrasonic Doppler measurement system can be used to build a velocity profile for product flowing through a pipe, which can be an invaluable tool for process engineers.

Pacific Northwest scientists have developed other acoustic monitoring methods for determining product composition and uniformity. Depending on what is or isn't in the mixing bowl or process tube at the time, or depending on the length of time the product is being mixed, the product exhibits different sound speeds and dissipations. In some cases, particle sizes and concentrations in a product can be measured ultrasonically under process conditions.

An Ultrasonic Blanchimeter lets you noninvasively monitor vegetable strips or cereal grains for determining the extent of blanching. The technique provides a means to establish robust set points without off-line testing. To address challenges associated with solids settling, line plugging or other process anomalies, the lab has developed an ultrasonic Densimeter. The Densimeter is a noninvasive tool that measures fluid density in pipes or vessel walls. An Ultrasonic Pulse Echo (UPE) technology distinguishes a variety of materials that all flow through the same piping, such as raw ingredients, product, water and cleaning solutions. It facilitates establishing clean-in-place practices.

Scientists are working with several food processing and consumer product companies on improving the quality of such products as potatoes, tomato paste, pudding, bread dough, cookie dough, cooking oils, sauces, cake mix, beef, chicken and corn.

Further information. Walter Weimer; phone: 509-375-6922; fax: 509-375-2029; email: walter.weimer@pnl.gov.