vacuum dryer in industrial and agricultural production
Compared with other operation links in industrial and agricultural production, the task of energy saving and pollution prevention in drying process is particularly urgent. First of all, the drying operation involves a wide range of fields, and China's drying energy consumption accounts for almost half of the total industrial energy consumption compared with the UK, reaching 12%. Secondly, the environmental pollution caused by drying is quite serious. In the most widely used conventional drying equipment, more than three-quarters are hot-air drying. This kind of drying equipment has a serious environmental pollution. It is not only an indispensable basic production link for a large number of industrial and agricultural products, but also a large energy consumer in China. The energy consumption accounts for about 12% of the total energy consumption of the national economy. In addition, the pollution of drying industry is also a big problem. Strengthening the drying technology of vacuum dryer is closely related to the development of the whole national economy.
With the diverse needs of the equipment, we have been working to design and manufacture a variety of vacuum dryers suitable for customer specific applications. These vacuum dryers are used for rapid drying at low temperatures, including drying deep holes in a way that does not damage the product. In these vacuum dryers, the dried material is exposed to vacuum, so that the boiling point can be reduced and water vapor can be caused even at low temperatures Hair.
The vacuum dryer can be disinfected before drying, and there is no impurity in the drying process, which meets the requirements of GMP. In vacuum, the boiling point of the material solution decreases, which makes the heat transfer force of the evaporator increase. Therefore, the heat transfer area of the evaporator can be saved for a certain amount of heat transfer. The heat source of evaporation operation can be low pressure steam or waste heat steam. The evaporator has less heat loss. Vacuum dryer belongs to static vacuum dryer, so the shape of drying materials will not be damaged.
The so-called vacuum drying is to heat and dry the materials in vacuum. If the vacuum pump is used for pumping and dehumidification, the drying speed is accelerated.
Note: if the condenser is used, the solvent in the material can be recovered through the condenser. If the solvent is water, the condenser can not be used to save energy investment.
The work piece is put into the vacuum box and vacuumized in order to remove the gas components that can be extracted from the material of the workpiece. If the workpiece is heated first, the gas will expand when heated. Due to the excellent sealing performance of the vacuum tank, the huge pressure generated by the expansion gas may cause the toughened glass of the observation window to burst. This is a potential danger. This danger can be avoided by following the procedure of vacuumizing and heating.
The heated gas is directed to the vacuum pressure gauge, which produces a temperature rise. If the temperature rise exceeds the temperature range specified by the vacuum pressure gauge, the indication error of the vacuum pressure gauge may occur. The correct use method should be first vacuumized and then heated. After reaching the rated temperature, if it is found that the vacuum degree has decreased, the pump should be added properly. It is beneficial to extend the service life of the equipment.
If the procedure of heating first and then vacuuming is followed, when the heated air is pumped out by the vacuum pump, the heat will inevitably be carried to the vacuum pump, which will lead to the high temperature rise of the vacuum pump, which may reduce the efficiency of the vacuum pump.
In the drying process using convection, the vapor pressure of the liquid discharged at a specific temperature or pressure is critical. If the vapor pressure is equal to or less than the liquid content in the atmosphere, drying is not possible. If the vapor pressure is greater than the liquid content in the atmosphere, the rate of drying depends on the gas exchange (convective surface, air flow). Since the vapor pressure usually increases at higher temperatures, thus facilitating drying, the drying process of the product to be treated is designed using the parameters required for the type of liquid to be discharged. Vacuum dryer is suitable for low temperature drying of heat sensitive materials which are easy to decompose, polymerize and deteriorate at high temperature; it is widely used in pharmaceutical, chemical, food, electronic and other industries.