In order to solve the problem of drying high-viscosity paste materials in the chemical industry, a rotary flash dryer was successfully developed in 1970. However, the "70" rotary flash dryer has many shortcomings, mainly because the powder easily enters the high temperature zone, and it is easy to cause the material to be overheated and agglomerated and deteriorated, and the mechanical stability of the rotating component is poor. In 1978, the "70" was remodeled. Although the "78" type has made great progress, there are also disadvantages such as instability of the powder bed, fluctuations in the outlet temperature and residual moisture of the product. In 1983, a major improvement was made to the "78" model. Now the equipment we have seen is basically a model after two large structural improvements, called the "83" type. The structure of the machine has the following advantages compared with the first two:
1. The bottom of the drying chamber is provided with an inverted cone structure, so that the air circulation cross section is continuously expanded from bottom to top, the bottom gas velocity is high, and the upper gas velocity is low, so that the lower large particles and the upper small particles can be in a good fluidization state. The inverted cone structure also shortens the length of the agitator shaft cantilever and increases operational reliability and stability. The bearings are placed outside the machine to avoid long-term work in the high temperature zone and prolong the service life.
2. While the wet material is dispersed and pulverized by the stirring teeth, it is twisted to the wall and bonded to the inner wall. If it is not scraped in time, the quality of the product will be affected. The top of the stirring tooth is provided with a scraper, which can be scraped off in time. Material on the wall to prevent overheating.
3. The upper part of the drying chamber is provided with a grading ring. The main function of the drying chamber is to separate the granules with large or non-dried materials from the qualified products and block them in the drying room, which can effectively ensure the product size and moisture requirements.
4. The cold air protection at the entrance of the hot air at the bottom of the cone prevents the material from coming into contact with the high temperature air to cause overheating and deterioration.
5, continuous operation, feeding amount, hot air temperature, product particle size can be controlled within a certain range, thus ensuring the indicators of dry products.
6, the drying system is closed, and operating under micro-negative pressure, dust does not leak, protect the production environment, safe and hygienic.
7. The equipment is compact in structure and small in floor space. It integrates drying, pulverization and grading. It is an optimized combination of fluidization technology, swirling technology, pulverization grading technology, spray technology and convection heat transfer technology, which greatly simplifies the production process and saves equipment investment and operation costs.
As a new type of machine, the rotary flash dryer has many advantages. It has attracted a lot of interest from users as soon as it appears, and it has been widely used in China.