Right after being pressed by the ring die pellet mill, the finished pellets are soft, moist and hot and they release water vapor. Therefore in order to ensure the hardness and stability of pellets and guarantee better usage or storage, it is necessary to cool hot pellets down to a lower temperature. In this case, a cooler is of the essence.
GEMCO counter flow type pellet cooler mainly used in the process of pellet cooling. It is one of the latest coolers prevailing across the globe, the process is like this: feed the hot pellets into the cooling chamber, filing evenly onto the turning plates, the plates turn to release the pellets in the bottom to drop through gap to the discharger once the material piling touches the upper lever sensor. And the pellets in the cooling chamber fall down slowly, until they drop under the lower sensor and the plates reset. This step is finished and when new pellets are fed into the cooler it starts over again. In the discharging period, while cool air blows upwards, the hot pellets drop slowly downwards, hence heat exchange happens in the counter flow, and pellets will be cooled gradually and forwardly, the cooler pellets at the bottom exchange heat with cooler air and the hotter pellets on the top exchange heat with hotter air. This design can reduce the temperature difference between the hot pellets and the cool air which can avoid the crack of pellets because of a drastic temperature change; therefore, the cooling effect goes outstanding. And it is low energy consumption and convenient operation.
During the process of making biomass pellets, after pelletizing, it is unavoidable that there will be powder material mixed with pellets, or sometimes, there are some pellets not processed perfectly, in this case, if you leave the powder material and faulty pellets in the processed pellets, it will reduce the usage rate of the final pellets, in addition, when packing the pellets, the powder will be at the bottom which will affect the appearance. Also if you use a vibrating screen to separate the impurities from the pellets, the impurities can be recycled which can save energy and improve the efficiency.
The working principle of a vibrating screen
The screen is driven by the motor to vibrate in different ways, and then the mixed material in the screen chamber is thrown up and down, and simultaneously, there are different sizes of meshes in different screen, through vibrating the powder will fall onto different screen and is classified into different size then finally will be discharged from each outlet. The features of GEMCO vibrating are it has full-locked structure, no dust float, no mesh block, no liquid leakage, in addition, it is low energy consumption and easy to maintain due to the simple structure.