• 产品名称: Thin-layer drying system

Drying equipment


The successful development of Thin-layer drying system provide new-style drying technology and equipment for plant extraction, additive, vegetable & fruit further processing and so on industries. 



     Thin-layer drying system is a new-style low temperature drying equipment which developed by Shanghai Minjie Machinery Co., Ltd. It adopts low temperature radiation & thin layer drying technology which is called "the fourth generation drying technology" by international drying academic world. Equipment has "high efficiency, high quality, low energy consumption" features, can be widely applied in: food, health care products, pharmaceutical, chemical industries, and so on.


Please watch the introduction of Thin-layer drying system



Working principle


      Thin-layer drying system consist of feed and distributing system, heating and drying system, low temperature air exhausting system, cooling system and discharging system, and the composition principle is shown in the figure.




      Thin-layer drying system use recycled heat fluid medium as heating source. Wet material is distributed on the conveyor film, form a thin layer of material. The conveyor film run at a set speed and keep in close fit with the heating liquid. By radiation, the thermal energy of the heating medium is transferred into the wet material through conveyor film, and water of the wet material is heated and evaporated.
     During the drying, material’s moisture content is gradually reduced till to the end of drying. At the end of the conveyor film, material be cooled though low temperature water. It helps material be removed from the conveyor film and it can reduce temperature’s affect to product’s quality. By controlling the running speed of the conveyor film, the drying time can be adjusted.

      Thin-layer drying system, usually use hot fluid as heating medium (usually water), hot fluid surface be covered with the conveyor film which are made of a special material with poor heat conduction. So, circulating water’s thermal energy loss is limited. When there is no wet material on the conveyor film, the thin film can reflect back the infrared which was radiated out by water. Because there is only heat conduction existing here and now, so thermal energy loss is very limited; when wet material is distributed on the conveyor film, the wet contacting surface is similar to a "refraction window”. When “refraction window” open, the radiant thermal be allowed to pass through, at same time thermal energy be transferred to the wet material by means of conduction and radiation, the water of the wet material be evaporated. After material be dried, the water film which between material and thin film, becomes an air thin layer. The air film has a wider refraction angle than the water film, so it is easier for total reflection. When "refraction window" close, the thermal energy can only be transferred by conduction, because conveyor film is poor heat conduction, so it can avoid overheating and thermal energy loss. During the drying process, there are constantly temperature contrast between material and the heating medium (usually be stably controlled 15-20°C lower than the heating medium temperature).

      Adopting thin layer distribution system, the moisture meet less resistance when escapes. At same time, air draft device be installed at the upper part of heating surface, in this way evaporated moisture can be removed in time, strengthen the dehydration, so even at atmospheric pressure, it can reach a larger evaporation capacity to meet the drying production requirement.


Performance feature

Main performance parameters

● Heating temperature: 50-95 ℃

● Heating medium: water

● Evaporation capacity: 3-10 kgh

● Heating area: 6-50 optional

Distribution thickness: 1-5 mm

● Operation control:automatic control

Product moisture: 3-8%  adjustable

Features and advantages

●As for low temperature operation, material temperature can be controlled effectively, nature products’color, aroma and taste can be well kept, the final dried products’quality is very high. The dried products’quality is basically similar to freeze-dried products.

● Since it needn’t vacuum system, Thin-layer drying system have features as follows: simple structure, low investment cost, easy to operate and low running & maintenance cost.

● Low temperature operation, low thermal energy loss, Thermal energy utilization rate of 75% or more, various energy resource can be utilized.



Application scope

Thin-layer drying system can be widely applied in food, health care products, agricultural products’processing, pharmaceutical, chemical and so on industries’drying production.
Vegetables: pumpkin, carrots, yam, purple yam, tomatoes, purple potato, and so on.
Fruits and vegetables: papaya, Chinese wolfberry, strawberry, blueberry, raspberry, pineapple, mango, and so on.
Sugar: pullulan polysaccharide, βglucan and so on.
Chemical material: PVP, xanthan gum, and so on.
Aquatic products and algae: kelp, blue-green algae, durum, and so on.




Core technology

Chinese patent: “Low temperature thin layer drying system”ZL201520801797.5

Unique thin layer distributing technology and device, can achieve that material be uniformly, continuously, stably distributed to 1-5mm thickness.

Unique conveyor film joint technology and dedicated device, can guarantee mechanic intensity, seal performance and size stability of conveyor film’s jointed part. The conveyor film can run stably in long time.


Equipment specification 




Heating zone


evaporation capacity for reference(kg水/h)



























Application cases

Typical application case - carrot drying

Moisture content in the paste: 89.4%

Heating temperature: 95°C

Drying time: 75 minutes

Weight loss of dried product: 5.9% Water evaporation rate: 4.5 - 6.0 kg/h