Principle and maintenance of vacuum dryer

The vacuum dryer 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 emptied from the outlet of the vacuum pump by the dry dust collector, the wet dust collector and the 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. The operation of the vacuum dryer is lower than that of the box dryer. It can receive the effective moisture content in the guess. The operation premise is better and the management is more convenient. Its disadvantages are low production capacity, complex layout of equipment, and easy damage of blender blades. This dryer is widely used in dyestuff and pharmaceutical industry. For example, the drying of materials such as drying reduction dyeing center, silicone sealant, anthraquinone sulfonic acid, reduced olive green R, salicylic acid center, caprolone polymer, diaminoanthraquinone, etc. Maintenance common sense of vacuum dryer: 1. Vacuum dryer shell must be effectively grounded to ensure safe use. 2. The vacuum dryer should be used in the environment where the relative humidity is less than 85% RH, no corrosive vacuum dryer gas, no strong vibration source and strong electromagnetic field exist. 3. There is no explosion-proof or corrosion-proof treatment in the vacuum dryer's workroom. No explosive or corrosive gas can be put into the vacuum dryer. 4. Vacuum pump can not work for a long time. Therefore, when the vacuum degree meets the requirements of vacuum dryer, the vacuum valve should be closed first, and then the power supply of the vacuum pump should be closed. When the vacuum degree is less than the requirements of the vacuum dryer, the vacuum valve and the power supply of the vacuum pump should be turned on, and the service life of the vacuum pump can be prolonged. 5. If the goods of vacuum dryer are wet, it is better to add filter between vacuum box and vacuum pump to prevent damp gas from entering the vacuum pump, causing vacuum pump failure. 6. Vacuum dryer articles such as vacuum dryer after the change to light weight, small size (for small particles), should be in the workroom vacuum outlet with barrier net, in order to prevent vacuum dryer material suction and damage the vacuum pump (or solenoid valve). 7. Vacuum dryer after many times of use, can not produce vacuum phenomenon, at this time should replace the door seal or adjust the box door button extension distance to solve. When the vacuum box vacuum dryer temperature is higher than 200 ~C, there will be slow air leakage (except 6050, 6050B, 6051, 6053). At this time, the back cover of the vacuum dryer is removed and the heater base is loosened by the inner hexagonal wrench, and the sealing ring is changed or the heater base is tightened to solve the problem. 8. if the rubber plug of the bleed valve is difficult to rotate, it can be lubricated with proper amount of grease. (e.g. Vaseline) 9. Do not remove the cover of the left side box (except 6090 and 6210 models) except for maintenance to avoid damage to the electrical control system. 10. vacuum dryer should be kept clean. The door glass should not be cleaned with reactive chemical solution. Wipe with soft cotton cloth. 11. If the vacuum dryer is not used for a long time, wipe the exposed electroplated parts and coat them with neutral grease to prevent corrosion, and cover them with plastic film dust shield and place them in the room of the vacuum dryer to avoid damp damage to electrical components and affect their use.