Food industry, drying equipment

Shelf Devices Equipment having heated and/or cooled shelves is available but is httle used for divided-sohds heat processing. Most extensive use of stationaiy shelves is freezing of packaged solids for food industries and for freeze drying by sublimation (see Sec. 22). 

Tab. 6.4-5 List of some dry and dried food materials as well as mixed food formulations that are converted by growth agglomeration into free flowing, granulated, often instant, and dust free products for easy packaging, metering, and reconstitution Tab. 6.4-6 Listing of some materials that are processed wifli roller extrusion presses and associated equipment in the food industry (in alphabetical order)...

Economical microwave equipment suitable for the requirements of industrial freeze drying of foods and pharmaceuticals on a large continuous scale is not yet available. 

Under these circumstances, it can be easily appreciated that a continuous freeze-drying plant is a highly sophisticated piece of equipment which most often is designed and put together by the food industry itself, which keeps the whole development strictly confidential and assembles different components purchased from multiple unconnected manufacturers. 

Process constraints may be different for the pharmaceutical and food industries, as well as for the above types of product. It follows that a process modification can be beneficial or applicable only to specific material types or equipment. For example, in the pharmaceutical industry sterility is often a predominant requirement, while minor attention is given to energy efficiency. Therefore, a new technology that enhances heat and mass transfer, but compromises sterflity conditions, is not suitable for the drying of drugs. 

During the 1960s, the food industry was forced to increase its production to cope with increased requests from the market for freeze-dried foodstuffs, such as milk and coffee. Surprisingly, the above-described objective was achieved not by improving preexistent equipment but, quite oppositely, by abandoning it in favor of new technologies. The food industry, in fact, revamped its equipment and moved away from batch to semi-continuous and, as a last resort, to continuous operations. 

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