The classification system of the circulating tube air flow crusher is to achieve; Precise Particle Control; The core of it revolves around centrifugal force sorting, and by dynamically adjusting the separation threshold, it ensures that only fine particles that meet the standards are discharged, while coarse particles are returned to the crushing zone for cyclic processing.
        The core structure of the grading system         The grading system of the circulating tube air flow crusher is mostly a built-in centrifugal classifier, consisting of three core parts that work together to achieve the grading function:
        Grading wheel: a high-speed rotating impeller (usually composed of multiple blades), which is the core component of grading, and the speed can be accurately adjusted by a motor (common speed range is 500-10000r/min).
        Grading chamber: an annular space surrounding the grading wheel, where the crushed gas-solid mixture enters from a tangential direction, forming a rotating airflow.
        Diversion structure: A diversion plate located at the inlet and outlet of the grading chamber, used to stabilize the direction of airflow and avoid turbulence that affects grading accuracy.
        The workflow of the grading system
        The essence of the grading process is; Using the balance between centrifugal force and airflow drag force to separate particles of different sizes; It can be divided into three steps:
        The gas-solid mixture, including coarse and fine particles, enters the crushing tube of the classification chamber and is initially crushed. It enters from the tangential inlet of the classification chamber with high-speed airflow, and under the guidance of the guiding structure, it moves in a circular motion along the inner wall of the classification chamber, forming a rotating airflow field.
        Separation of centrifugal force and drag force         Coarse particles: Due to their large mass and inertia, the centrifugal force they experience in a rotating airflow is much greater than the drag force of the airflow. They will be thrown towards the inner wall of the classification chamber, fall along the wall, return to the crushing tube through the return channel, and participate in impact crushing again.
        Fine particles: Due to their small mass and inertia, they are subjected to airflow drag force greater than centrifugal force, and will overcome centrifugal force to move towards the center of the grading wheel and enter the blade gap of the grading wheel.
        Qualified fine particles are discharged and collected into the gap between the blades of the grading wheel, and are carried into the central area with the rotation of the grading wheel. They are then extracted from the grading system by the negative pressure airflow (or dedicated induced draft fan) of the equipment and enter the collection devices such as cyclone separators and bag filters to obtain qualified ultrafine powder.
        The regulation method of grading accuracy
        The grading system can accurately control the particle size of finished products and meet different processing requirements by adjusting two key parameters:
        Adjust the speed of the grading wheel
        Speed increase: The centrifugal force generated by the grading wheel increases, and the separation threshold decreases (i.e. only finer particles can overcome the centrifugal force and enter the center), resulting in finer particle size in the finished product.
        Rotation speed reduction: centrifugal force decreases, separation threshold increases, and the particle size of the finished product slightly becomes coarser (suitable for scenarios where particle size requirements are not extreme but processing efficiency needs to be improved).
        The airflow velocity of the stable airflow parameter grading chamber (controlled by the gas source pressure) will affect the magnitude of drag force: excessively high airflow velocity may cause some coarse particles to be trapped; Bring it up; Mixing fine particles; If the airflow velocity is too low, it may cause some fine particles to be thrown towards the inner wall and return with the coarse particles due to insufficient drag force. Therefore, it is necessary to adjust the gas source pressure to maintain stable airflow velocity, and to achieve precise particle control in conjunction with the speed of the grading wheel.