The flash dryer is an ideal equipment for processing dispersible filter cakes and viscous paste materials, and was first used in the dye industry. After years of application practice, a variety of models have been developed and a series of products have been formed. According to different materials, it is connected in series with other drying equipment, which increases the application range of the equipment.
At present, the flash dryer has been widely used in the industrial production of dyes, pesticides, organic chemicals, and inorganic chemicals.
At present, flash dryers have been used in pharmaceutical, biological, food, chemical and other fields. However, the selection criteria are different in each field, because the requirements and parameters of dry materials in each field are quite different.
The flash dryer is mainly used for drying flake, strip and granular materials with good air permeability. It is especially suitable for materials with high moisture content such as dehydrated vegetables and Chinese herbal medicines, but the temperature of the material is not allowed to be high; flash dryer The series has the advantages of fast drying speed, high evaporation intensity and good product quality. For the paste material of the dehydrated filter cake, it can also be dried after being granulated or made into a rod. After drying, it can be packaged directly without crushing.
The flash dryer is a vertical fluidized bed dryer with a rotary crushing device, which can complete the crushing, drying, grading and other operations of materials at the same time. The main body of the flash dryer is a cylindrical drying chamber, which is composed of a crushing fluidization section at the bottom, a drying section in the middle, and a classification section at the top. The crushing section at the bottom is equipped with an agitator, which drives the hot air entering the drying chamber from the distribution chamber to generate a high-speed rotating airflow to form a fluidized bed; at the same time, it produces a strong stirring and crushing effect on the material, which strengthens the mass and heat transfer and accelerates the material's drying process. drying speed.
There is a screw feeder in the drying section, and the feeder is driven by a speed-regulating motor, and the speed is adjusted by a frequency converter. There is a grading ring in the top grading section, and the diameter of the grading ring is selected according to the granularity requirements of the product. The dried material fine powder can be sent to the cyclone or bag filter with the airflow for collection.
A scraper is set on the stirring teeth of the flash dryer. When the material is crushed by the stirring teeth, it is thrown to the wall of the machine and sticks to the wall. If it is not scraped off in time, it will vibrate the equipment in severe cases, and even cause the agitator to block and stop turning. The scraper is set on the stirring tooth of the flash dryer, which can peel off the material stuck on the wall of the machine in time to avoid sticking to the wall.
The rotation of the stirring shaft is controlled by a stepless speed regulating motor. Choose different speeds according to the product particle size requirements, the faster the stirring shaft rotates, the smaller the product particle size. The rotation speed of the screw conveyor of the flash dryer feeder is controlled by an inorganic speed-regulating motor.
Control the feeding speed according to the material properties and drying process parameters. A classifier is set on the upper part of the flash dryer. By changing the hole diameter of the classifier and the height of the classification section, and then changing the air flow rate, the size and quantity of the particles leaving the dryer can be controlled, and finally the water content and the residence time of the material in the drying section can be controlled.
The bottom of the flash dryer is equipped with an inverted cone structure, so that the drying gas flow section gradually expands from bottom to top. The bottom airflow is relatively large, and the upper airflow is relatively small, so as to ensure that the large particles in the lower The small particles are also in a fluidized state, and make the hot air rotate along the vertebral body, increase the wind speed at the bottom, reduce the length of the cantilever part of the stirring shaft, and increase the safety and reliability of the operation; the bearing can be placed outside the machine to effectively prevent the bearing from being in the air. Work in the high temperature zone, thus prolonging the service life of the bearing.
The flash dryer has a compact structure and a small footprint. It integrates drying, crushing and grading. It is an organic combination of swirl technology, fluidization technology, spray technology and convection technology. After drying, it does not need to be crushed or sieved. The production process is simplified, and power and equipment costs are saved.