What Is a Fluid Bed Dryer?

Mary McMahon
Mary McMahon

A fluid bed dryer uses gas or heated air to dry certain products. The equipment effectively forces the products to behave like a fluid as they move through the machine from the feed inlet to an outlet which discharges the dried and finished products. Different zones can allow for heating and cooling as needed, with each zone controlled by the operator. Manufacturers can use a fluid bed dryer for an activity like preparing powder, where the device dries and separates the power before cooling it at the very end so it can be packaged.

Scientist with beakers
Scientist with beakers

The equipment includes a large processing chamber with a perforated plate through which heated air or gas can pass. As products are fed in, they float on the gas, receiving maximum surface contact with the heat so they dry quickly and evenly. Some machines also have heater bars to increase the temperature and speed the process even further. Materials in the fluid bed dryer behave almost like a boiling liquid, bubbling along the length of the chamber until they reach the far side, where they can be discharged.

For increased efficiency, many devices use a recycling system. This brings the heated gas or air back around, where it can be filtered and run through again to lower operating costs. Heated bed dryers can also be controlled with a variety of adjustments to temperature and pressure in order to handle different products. The heated gas can be more or less dense, for example, to compensate for particles of different weights, ensuring that they float rather than sinking to the bottom. Vibration can be added for stubborn materials.

These devices allow companies to granulate or pelletize materials, like powdered milk and other processed foods along with medications and coatings for industrial products. Equipment is usually designed for a specific family of applications and in the case of a food processing fluid bed dryer, the device may have a self-cleaning function. Food products, especially animal products like milk, can tend to stick to process equipment, creating a risk of contamination and clogging. Self cleaning breaks down the sticky proteins to keep the equipment in working order.

Lease or rental options may be available to allow a company to use a fluid bed dryer on a short term basis. This can be useful for limited production runs or companies that want a chance to try products before committing to a purchase. Used equipment can cut costs for companies looking to acquire a fluid bed dryer, while manufacturers can produce custom machines for specific applications that may not be met by existing product lineups.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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