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42 / March 2021 powderbulk.com configuration to save on long-term overhead expenses related to routine maintenance. Rectangular fluid-bed dryer-coolers also require extensive rigging to stabilize the machine because of the high-intensity vibrations. In contrast, most cir- cular vibratory fluid-bed dryer-coolers are equipped with internal vibration cancellation technologies and don't need to be mounted to walls and floors to remain stable in place. Furthermore, circular units don't require as complex an installation process as their rectangular counter- parts. Because of the configuration, circular units and the entire fluid-bed system can be self-contained and skid-mounted on common frames with casters, ready to plug in and run (plug-and-go). Fluid-bed systems can include heaters, coolers, moisturizers, blowers, and dust collectors. This offers pilot plants fast setup, compactness, mobility, and flexibility — features that can't be included with rectangular units that are two to three times larger and heavier at equivalent capacities. When sourcing a vibratory fluid-bed dryer-cooler, a circular model should be considered for its consis- tent and efficient drying results, quick-clean sanitary design, small footprint, low initial and operational costs, and minimal downtime. Rectangular options are appropriate in high-volume continuous applica- tions where there's plenty of floor space and the need for pristine sanitation isn't highly prioritized. Today's circular vibratory fluid-bed dryer-coolers are available in small-batch, pilot plant, and lab sizes along with larger models suitable for continuous processing appli- cations, offering a wide range of options suitable for most applications. PBE For further reading Find more information on this topic in articles listed under "Drying" in the article archive on PBE's website, www.powderbulk.com. Sunny Nwadinma (snwadinma@kason.com) is the senior applications engineer at Kason Corp. He handles product lines including circular fluid-bed dryers, coolers and moisturizers, circular vibratory and centrifugal sift- ers, and static sieve screeners. He studied engineering technology at Essex Community College and studied mechanical engineering and science at the New Jersey Institute of Technology. Kason Millburn, NJ 973-467-8140 www.kason.com fluid-bed dryers have a deeper bed; therefore, they can have greater throughput per square foot of space they occupy on a factory floor. Fast and easy sanitation in a circular vibratory fluid-bed dryer also reduces costs and downtime. Rect- angular dryer-coolers can take several hours to clean, while most circular fluid-bed dryer-coolers can be cleaned in less than an hour. For food and pharmaceu- tical applications, this kind of fast sanitation can make a huge difference both in terms of costs and in terms of consumer safety and quality assurance. Another important safety feature for some produc- tion lines is the explosion-proof design of the circular fluid-bed dryer-coolers. This isn't available for every fluid-bed unit, so if you're working with volatile or dangerous materials of any kind, make sure to check with the dryer manufacturer regarding the level of explosion-proofing for its units. Finally, circular vibratory fluid-bed dryer-coolers are quiet, courtesy of vibration reduction mech- anisms. While the blowers make some noise, it's typically only up to 85 decibels. If required noise levels are lower, then a blower can be fitted with a noise-reducing silencer. Rectangular vibratory fluid-bed dryers enable high throughput In general, rectangular vibratory fluid-bed dryer-cool- ers are suitable for high throughput applications and where sanitary and quick-clean features aren't a con- cern. Most rectangular fluid-bed dryer-cooler units can be configured to any size, and large conveyors can provide very high throughput for fluid beds. If you have a very high-throughput application and have a lot of floor space for a fluid-bed dryer-cooler, then a rectangular model might be a good fit. Depending on the material being dried, its bulk density, temperature limits, particle size distribution, and moisture content, high throughput would normally be considered 25 tons per hour or higher. This option is only practical for larger-scale indus- trial applications and if you have shifts that provide ample downtime for sanitization (if required). Clean- ing rectangular units also requires a certain degree of expertise as maintenance staff must open and disman- tle covers and get into the dryer-cooler to clean it. If your production line has shifts that can accommodate a more extensive sanitization routine, or if there are no major sanitary requirements to take into consideration for your specific application, then a rectangular unit may be appropriate. However, if you can accomplish the same throughput needed with an easier-to-clean circular dryer-cooler, then you should adopt a circular