Vacuum Dryer is a heat reducing material moisture machinery and equipment for drying objects. Vacuum drier by heating the moisture in the material (generally refers to water or other volatile liquid component) vaporization overflow in order to obtain a predetermined moisture content of the solid material.
The vacuum dryer drying equipment is a good in recent years, due to the social development needs of the natural drying is far from meeting the needs of people, so the vacuum dryer been widely used in recent years.
The Vacuum Dryer industry has a wide range of applications in modern production over the course of, on the whole, he has three major trends:
Vacuum drying with low drying temperature, dry indoor relative hypoxia can avoid fat oxidation, pigment browning a series of advantages, suitable for drying of heat-sensitive food material, in addition to equipment costs, drying costs are relatively low, the vacuum drying has an important role in food drying midpoint
Vacuum drying with microwave heating technology or other drying methods combined, there are a lot of new vacuum drying device, giving new meaning to vacuum drying and vitality
3. Vacuum microwave drying absorption of microwave heating and vacuum drying the advantages of both, is a promising drying technique is recommended China to accelerate research and development of vacuum microwave drying device.
The main factors to affect the vacuum dryer drying effect:
1, the drying temperature: heat is key to open the resultant force between the water molecules and the absorbent polymer. When above a certain temperature, the gravitational force between the water molecules and the polymer chains will be greatly reduced, the water vapor to be taken away by the dry air.
2, dew point: the first removed in a vacuum dryer, the wet air, so that it contains very low residual moisture (dew point). Then, by heating the air to reduce its relative humidity. In this case, the lower the vapor pressure of the dry air. By heating, the water molecules of the interior of the particles get rid of the bonding force Bound to the spread of the air around the particles.
3, time: in the air around the particles, the heat absorption and the water molecules to the particle surface diffusion requires a certain time. The resin suppliers Describe a material effective drying time must be spent in the proper temperature and dew point.
4, Airflow: the dry hot air, which heat transfer to the particles in the drying hopper, to remove the moisture in the surface of the particles, and then return the moisture to the dryer. Therefore, there must be sufficient airflow to the resin is heated to the drying temperature, and this temperature is maintained a certain amount of time.
When poor drying should find the problem.
1, vacuum dryer condition
Check the vacuum dryer, with particular attention to the air filter and hose. The clogged filter or a flattened hose will reduce the airflow, thus affecting the operation; damaged filter will pollute the desiccant, inhibiting its absorbent capacity; rupture of the hose may be moist ambient air introduced into the drying gas stream, caused by the desiccant prematurely moisture and high dew point; the poor insulation measures hose and drying silo will also affect the drying temperature.
2, dry gas path
Detection drying temperature in a dry gas path, it should be in the hopper entrance, in order to compensate for the heat loss of the vacuum drier in the hose. The silo inlet air temperature is low, it may be due to improper adjustment of the controller and the lack of the insulation layer, or a heater element, the heater current contact device, thermocouple, or controller malfunction. In addition, the entire drying process of monitoring the entire drying temperature, is also very important to observe the temperature fluctuations in the desiccant replacement.
If the material from the vacuum drier out did not get proper drying, drying silo should check whether there is enough space to provide a sufficiently effective drying time. The effective drying time refers to the the particles actual exposure time in the appropriate drying temperature and the dew point. If the residence time of the particles in the hopper is not enough, the lack of proper drying. Therefore, we should pay attention to the size and shape of the particulate material or broken material, they will affect the bulk density of the dried material and the residence time. |
Descriptions vacuum dryer, development, analysis summarizes the reasons that affect the drying effect