There are three main kinds of freeze dryers: rotary, manifold and tray freeze dryers. Rotary freeze dryers are generally used when working with liquids. Small amounts of material are frozen by manifold dryers, and tray freeze dryers produce the driest product ready for long-term storage. Read More…
Leading Manufacturers
Carrier Vibrating Equipment, Inc.
Louisville, KY | 502-969-3171Carrier is a manufacturer of high quality dryers in addition to many other related products, including coolers, screens, air knife separators, spiral elevators, feeders & conveyors.
Dürr Systems, Inc.
De Pere, WI | 920-336-5715Dürr Megtec provides customized systems for: regulatory compliance; improvement in working environment and in neighbor relations by reducing odor from industrial processes and helping to reduce greenhouse gas emissions and process energy management.
Baker-Rullman Manufacturing, Inc.
Watertown, WI | 920-261-8107Established in 1980, Baker-Rullman Manufacturing, Inc. is a leader in the engineering, design, and fabrication of rotary drum dryers, modular steel bins and hoppers, structural steel, feed and seed mill systems, and custom metalwork. At Baker-Rullman Manufacturing our team of experienced, knowledgeable engineers are ready to get your project off the ground. With more than 30 years of project management experience, we can develop custom designed turn-key solutions to meet your needs!
FEECO International, Inc.
Green Bay, WI | 920-468-1000Since 1951, FEECO has designed and manufactured both direct and indirect rotary dryers for a variety of industries around the world. All dryers are customized to fit the unique processing requirements of the material, with material testing/process development assistance available, in addition to post-sale support including inspections, parts replacement, and more.
Heyl Patterson Thermal Processing
Carnegie, PA | 412-788-9810For over 125 years, Heyl Patterson has custom-engineered thermal processing solutions that are trusted in dozens of industries worldwide. We specialize in high quality drying equipment, such as Rotary Calciners, Rotary Dryers, Fluid Bed Dryers, Flash Dryers, Disc Dryers, Sludge Dryers, Conduction Dryers and Soil Remediation Units. Our pilot plant testing lab helps determine the best technologies and equipment for any application, and we support our clients for the life of their equipment.
Freeze Dryers - Central Air CompressorFreeze dryers are used by the pharmaceutical industry for increasing the shelf life of vaccines, for preserving certain strains of bacteria and for ease of storing and shipping certain products.
Freeze drying removes water and bulk while maintaining flavors and nutritional content and is subsequently used with food and beverages like instant coffee, fruit and herbs. Freeze drying is also useful in chemistry and biotechnology because it can make products easier to dissolve in water and remove impurities. Some museums or conservation agencies use freeze dryers to dry and preserve artifacts, manuscripts and animal or floral specimens.
Freeze Dryers - Central Air CompressorThe three kinds of freeze dryers - rotary, manifold and tray - vary in size and material. The industrial machines are typically tray freeze dryers and can be hundreds of feet long, either vertically or horizontally oriented. Stainless steel is most commonly used because it is sanitary and can be temperature controlled very effectively.
Products are held on trays on shelves in large boxes or carried on a conveyor belt if the dryer is continous. Freeze drying is a three step process. During the initial freezing, the material inside the dryer is cooled below its triple point, which is the lowest temperature at which the solid and liquid phases of the material can exist at the same time.
The temperature is usually between -50° and -80°C, and this is the most important step of the process. After the material is frozen it enters the primary drying phase. The pressure is lowered and enough heat is provided that sublimation occurs. Adding a vacuum to the dryer helps control and maintain pressure, and a cold condenser plate or chamber gives the water vapor a surface to freeze onto after it leaves the material.
The last step removes any unfrozen water molecules. In the secondary drying phase the pressure is lowered again and the temperature is raised, sometimes above the freezing point of 0°C. Any residual water evaporates from the substance, and the final water content is less than 5%.