The classifier at the top of the drying chamber of the rotary flash dryer is a circular plate with holes, similar to an orifice flow meter, but with a certain angle. The function of the classifier is mainly to separate the particles with large particles and no dry material to continue drying, so as to ensure that the product particle size distribution and the moisture content are uniform. The size and height of the spinner of the rotary flash dryer unit determine the dry size. When the height is constant, the smaller the pore size, the finer the particle size of the product.
The bottom of the rotary flash dryer is provided with an inverted cone structure, and the outer ring is an air distributor, which is connected with the hot air inlet, and the hot air is distributed in a ring shape around the outer circumference of the barrel, and the slit from the bottom of the barrel enters the fluidization section in a tangential direction. Forming a rotating wind field. The size of the annulus is the main parameter that directly affects the working condition of the dryer. The inverted cone structure can make the hot air circulation section become larger from the bottom to the top, the bottom gas velocity is relatively large, and the upper gas velocity is relatively small, thus ensuring the lower part. While the large particles are in a fluidized state, the upper small particles are also in a fluidized state. In addition, the rotating cone structure of the rotary flash dryer also reduces the length of the cantilever portion of the agitator shaft, increases the reliability of operation, and effectively prevents the shaft from operating in a high temperature region, thereby prolonging the service life of the bearing.
The fluidized section of the rotary flash drying unit is equipped with a stirrer for crushing and mixing materials, so that the hot air and the material are in full contact and the particles stay in the high temperature zone of the drying chamber for the shortest time, in order to prevent the material from being thrown under the action of the agitator. Four walls, the phenomenon of "crusting" on the four walls, resulting in failure to operate properly, the scraper is mounted on the stirring teeth, and there is a slight gap with the bottom of the chamber and the wall to ensure that the material is firmly bonded to the wall. Peel it off. In addition, the rotating speed of the rotary flashing unit stirrer should also be reasonably selected. The normal range of the rotating speed is 50-500r/min, and the stirring shaft and the bottom of the dryer have a good sealing structure.
The number of revolutions of the rotating shaft of the rotary flash drying unit is controlled by a stepless speed regulating motor. According to the product particle size requirements, different speeds are selected. The faster the stirring shaft speed, the smaller the particle size of the product. Rotary flash dryer unit is equipped with a classifier on the top of the dryer. By changing the hole diameter of the classifier and the height of the classifier, the air flow rate is changed to control the particle size and quantity leaving the dryer, the final water content and the material in the drying section. The time of stay. The number of revolutions of the screw conveyor of the rotary flash drying unit feeder is controlled by an inorganic speed control motor. The feed rate is controlled according to the nature of the material and the drying process parameters.