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Flash Drier Relatively High Speed
- May 15, 2017 -

Flash Dryer is working principle: hot Flash Drier air by the inlet tube to the appropriate jet speed from the bottom of the dryer into the stirring and crushing drying chamber, the material produces a strong shear, blowing, rotating, so the material is centrifugal, shear, collision, friction and particles, and strengthen the mass transfer heat. At the bottom of the dryer, the larger and more wet pellet is broken Flash Drier by mechanical and low moisture content, particles of smaller particles by rotating air entrainment rise, in the rise process further drying, due to the gas-solid two-phase rotation flow, solid phase inertia greater than gas phase, Flash Drier solid gas two phase relatively large, strengthen two phases of mass transfer, so the machine production intensity.

The operating principle of flash dryer is easier to understand. We can divide the whole drying process into 4 phases — crushing stage, gas-solid mixing phase, Flash Drier drying stage and granularity grading stage.


1, crushing stage: Fragmentation is the whole process of flash drying the first step is also a more important step. The drying material state is mainly paste, cake-shaped. If not broken can not be flash drying, so we can get a conclusion: strong viscous materials such as direct use of Flash Drier flash dryer, the drying effect is poor, need to add additives to avoid the material agglomeration. The process is mainly mixed with the high speed rotating gas with the completion of crushing.


2, gas-solid mixing phase: After crushing, Flash Drier the material in the flash drying main tower in the heating medium full contact. The gas-solid mixing determines the size of the whole drying rate. In order to improve the airflow speed, the inverted cone structure device is arranged Flash Drier at the bottom of the flash dryer.


3, Drying Stage: The process is hot air evaporation material moisture process. The unfinished dry material is fallen by gravity and continues to be broken and dried; Flash Drier the dry material will move upward and proceed to the next stage.


4, granularity grading: Set the annular baffle on the top of the drying host, which is called the Flash dryer classifier. When the material movement passes through the classifier, it is subjected to centrifugal force, which presents the spiral upward trend of different rotating radius. Flash Drier The material of small diameter is discharged from the inner hole of the classifier; the larger particles are left in the drying chamber to continue crushing, to reach the standard granularity from the inner hole.

Drying process of rotating flash dryer

The heat exchange in the dryer is mainly Flash Drier based on the airflow and the particles, the tube wall and the particles of two kinds of heat exchange. The essence of drying process is the diffusion process of moisture. It is carried out by external diffusion and internal diffusion. External diffusion is the process of diffusion of moisture from the surface to the surrounding medium in the form of vapor. Internal diffusion is the process of moisture movement within the particles.

Rotating flash dryer adopts high speed hot Flash Drier airflow tangent direction into the barrel, due to the spiral movement of the airflow in the barrel, while reducing the medium temperature around the particles and increasing the flow velocity and temperature, this greatly improves the speed of the external diffusion. On the other hand, high-temperature airflow high speed impact is located in the lower part of the particles or small wet materials, mixing the blade in the barrel of the body, so that particles are broken, the size of the reduction, the length of the internal capillary is reduced, strengthen the effect of internal diffusion, reduce the resistance. Most of these particles are repeatedly broken in the cycle of high temperature and high mixing strength in the lower part of the barrel. Eliminating the caking of materials is also a powerful measure to promote internal diffusion, which strengthens the evaporation of granular water.

The flow pattern of particles and hot airflow: both convection and flow in the lower part of the barrel, and the coarse material is convection and flow repeatedly heat transfer. For fine-grained materials, the drying process can be completed instantaneously by parallel with the hot airflow. The drying of particles is actually drying by hot air with high temperature and low humidity. These particles are mainly composed of moisture adsorption, filling in the gap between the particles, the use of high temperature and low humidity conditions, the whole particles of heat conduction slow, causing local stress concentration and cracking, crushing, dispersing, accelerated drying process.