What is the working principle of the self-balancing return material of circulating fluidized bed boiler?

　　The self-balancing return device consists of a feed pipe, a moving packed bed, a return bed, a return pipe and an air chamber. During operation, the circulating material separated by the separator first enters the loosening chamber through the riser, and the fluidizing air is fed from the air chamber to make the loosening chamber and the return chamber in a fluidized state. When the material from the separator increases, the return material The static pressure in the riser increases, the return power increases, and the return speed increases. On the contrary, the return power in the return material riser decreases, and the return speed decreases, thereby realizing self-balanced return.