The pharmaceutical dryer for drying liquid raw materials is mostly frozen in the drying box, while the dryer for freeze-drying solid food is mostly dried by the dryer (cold storage and dryer drying). This is because the solid heat of the liquid and liquid dried solids is good, and the contact heat transfer is beneficial to increase the freeze-drying rate. The solid food is cut into loose piles, and there is a gap between the solids. The heat transfer effect is very poor. When drying, it is forced to cool by blowing. When drying, it needs to be heated by radiation to transfer heat evenly. Loose inside. Therefore, the drying box of the production medical dryer is mostly made into a shelf type, and the shelf is cooled (hot) medium, which can be cooled and dried, and can be heated and sublimated. The food drying of freeze-dried solid foods generally does not require shelf drying, but uses the cold storage drying described below. When the shelf is used for drying, the product is mounted on the shelf by a plate or a bottle, the shelf temperature is -40 to 50 ° C, and the drying time is generally 1 to 1.5 hours. In order to evenly freeze, it is necessary to keep warm for a while at low temperatures.
The amount of food-dried items is large, and the cost of a cold storage or dryer is much lower than that of a dryer. In order to make full use of the production capacity of freeze-drying equipment, food drying is usually carried out by a special cold storage or dryer. A cage (or cart) conveyor track is provided in the library. After the items are pre-treated, they are loaded into the tray. The trays are loaded into the cage (or cart) and sent to the cold storage by the conveyor. The temperature of the cold storage is -30~-40 °C, and it is cooled by air. The drying time varies depending on the size of the food. After drying, it is sent to the dryer of the dryer by the conveying track. Although the dryer does not have special refrigeration equipment, it is inserted into the box due to short transportation and packing time. After that, it is evacuated by a large-capacity vacuum pump, and the product does not melt during transfer.
The amount of food-dried items is large, and the cost of a cold storage or dryer is much lower than that of a dryer. In order to make full use of the production capacity of freeze-drying equipment, food drying is usually carried out by a special cold storage or dryer. A cage (or cart) conveyor track is provided in the library. After the items are pre-treated, they are loaded into the tray. The trays are loaded into the cage (or cart) and sent to the cold storage by the conveyor. The temperature of the cold storage is -30~-40 °C, and it is cooled by air. The drying time varies depending on the size of the food. After drying, it is sent to the dryer of the dryer by the conveying track. Although the dryer does not have special refrigeration equipment, it is inserted into the box due to short transportation and packing time. After that, it is evacuated by a large-capacity vacuum pump, and the product does not melt during transfer.
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