Vacuum drying equipment performance and characteristics

Vacuum dryer has many advantages: low oxygen content when dried under low pressure, can prevent oxidation and deterioration of the material to be dried, and can dry flammable and explosive dangerous goods; it can vaporize the moisture in the material at low temperature, easy to dry heat-sensitive materials; The valuable and useful ingredients in the dried material can be recovered; the toxic and harmful substances in the dried material can be prevented from being discharged, and can become an environmentally friendly type of "green" drying. Therefore, vacuum drying equipment is increasingly used.

The main disadvantage of the vacuum dryer is the need for a vacuum system capable of pumping steam, which results in high equipment investment costs, high operating costs, low equipment production efficiency, and low output. To overcome these shortcomings, many scientific and technological workers have made many efforts. At the same time, vacuum drying has many advantages. Some products have to use vacuum drying equipment. Therefore, the development of vacuum drying equipment will be promising. 1. Unbalanced development of continuous vacuum drying equipment at home and abroad In order to improve equipment production and ensure product quality, a variety of continuous vacuum drying equipments have been developed abroad more than ten years ago. However, due to the limitations of the technology level and people's perceptions, the development is slow.

1) Belt type continuous vacuum drying equipment Japan's Risen WL-VAQ type belt type continuous vacuum drying equipment is suitable for liquid materials, sludge, pastes, sloppy concentration and high viscosity for dryness. The BV-100.5 type vacuum belt type continuous drying device produced by Japan's Okawara Plant uses steam and conductive heating. The temperature in each zone can be adjusted, and the tension and speed of the conveyor belt can be adjusted. The Swiss company Bucher-Gade developed a series of continuous vacuum drying equipment with automatic cleaning devices.

Since 1995, he has been engaged in the design, manufacture, installation and service of belt continuous vacuum drying equipment. The technology is mature.

Domestic belt-type continuous vacuum drying equipment is rare. In 2004, the Guangdong Academy of Agricultural Sciences successfully developed a small-scale test equipment for the drying of banana powder with good results.

2) The continuous drying equipment for cereals has a large amount of dried grain, and it must use continuous drying equipment. In the past, all countries in the world developed a lot of grain drying equipment. Vacuum dried grains are used in seed drying because vacuum drying costs are too high. In fact, this is a misunderstanding. According to He Xiang, senior engineer of Zhengzhou Institute of Grain Science and Design, the continuous corn vacuum drying equipment developed by them has a production capacity of 60t/d. The fixed investment is slightly higher than hot air drying, and the operating cost and hot wind Dry and flat. If the quality of the dried product is taken into consideration, the breakage rate of the drying process, the waist rate, etc., the total cost of the vacuum drying at a low temperature is not higher than the hot air drying.

3) The continuous vacuum freeze-drying equipment is rich in food raw materials, and the product that needs to be lyophilized has a large output. Therefore, the continuous food freeze-drying equipment appeared earlier. Danish ATLAS company produced CONRAD-800 continuous freeze-drying equipment in 1985, used for freeze-dried coffee production, with a production capacity of 13t per day.