The vacuum dryer is a conductive heat transfer dryer.

Preparation of vacuum dryer before operation

1) clean the drying tank and keep the tank clean.

2) refer to the instructions of the vacuum pump to conduct a careful examination of the vacuum pump. Whether there is a serious emulsification phenomenon by observing the adequacy of the pump oil in the vacuum gauge. If the pump oil is not enough, add the correct type of vacuum pump oil through the oil inlet of the pump. If the pump oil has been emulsified seriously, it must be replaced, otherwise the vacuum degree will be seriously affected.

3) check whether the circulating pipeline of heat conducting oil is clear, and whether the cut-off valve before and after the heat conduction oil circulating pump is opened.

4) check whether the oil level in the expansion tank is normal. The liquid level gauge should be kept at 20-25cm in cold condition.

5) check condensers and condensate tanks in liquid containers and remove them if necessary. Vacuum pipeline pressure is normal pressure, not to restore to atmospheric pressure.

6) check whether the power, water and gas source needed for the operation of the equipment are normal.

7) check whether the numbers of the instruments are normal.

Vacuum drying equipment vacuum drying machine is a conductive heat transfer dryer. The material is not directly in contact with the heating medium. It is suitable for drying a small amount of muddy and pasty materials which are not resistant to high temperature and easy to oxidize. The moisture content is 15%~90%. The blades of the rake agitator are made of cast iron or steel and mounted on a square shaft. 50% of the blades are directed to the left and 50% to the right. The speed of the shaft is 7~8r/min, which is made by a motor sensitive worker with a gearbox. Active steering assembly is adopted to change the rotating target of the shaft and the rotating target of the agitator once every 5-8 minutes. Vacuum dryer has the advantages of simple layout, convenient operation, long utilization period, stable and reliable function, low steam consumption, strong practical function, good product quality, especially applicable to drying paste materials which are not resistant to high temperature, inflammable and easy to oxidize under temperature regulation. The dried material is added from the center of the shell. Under the stirring of the rake teeth, the shaft of the material moves back and forth, the appearance of the material contacting the inner wall of the shell is renewed constantly, the rake teeth are heated indirectly by the steam, the rake teeth are stirred evenly, the rods are destroyed, and the water on the surface of the material is discharged more conveniently and the moisture on the gasification is changed. The vacuum dryer is discharged from the outlet of the vacuum pump through a dry dust collector, a wet dust collector and a condenser.

When operating, first start the stirrer, add the dried material and seal the charging port. The steam pressure is usually 0.2~0.4Mpa (pressure). When the material is dried, the vacuum degree is about 700mmHg. The water evaporation intensity of the dryer varies with material characteristics, humidity, heating steam pressure and vacuum. For example, when the vacuum is 700 mmHg and the steam pressure is 0.2 Mpa (surface pressure), the potato starch is dried from 40% to 20% of the initial moisture content, and the water evaporation intensity of the dryer is 5-7 kg/m2?h。