Differences Between Freeze Dryer And Spray Dryer
Dryer refers to a mechanical device that uses heat energy to reduce the moisture content of materials. It is used to dry objects. Usually, there are adsorption dryers, spray dryers, and freeze dryers. As common drying equipment, freeze dryers and spray dryers have many differences, but few people know the following three differences.
1. Different principles
①The freeze dryer uses the principle of sublimation to freeze the water-containing substance into a solid state first, and then sublimates the water in it from a solid state to a gaseous state to remove the water and preserve the substance.
②The spray dryer is used to atomize the material in the drying chamber, and in the contact with the hot air, the moisture is quickly vaporized to obtain the dry product.
2. The drying time is different
① It usually takes about 24 hours for a freeze-drying machine to freeze-dry once, and the specific freeze-dried products are also different, which is longer than that of a spray dryer.
②The drying speed of the spray dryer is fast, and the surface area of the material liquid is greatly increased after atomization. In the hot air flow, 95%-98% of the water can be evaporated instantly, and the drying time is only a few seconds. It is especially suitable for heat-sensitive materials dry.
3. The dry product structure is different
①The freeze dryer dries in a frozen state, so the volume is almost unchanged, the original structure is maintained, and no condensation occurs.
②The use of high temperature spray by the spray dryer will destroy the organizational structure of the product.