The mixer of the self feeding mixer truck is a machine in which the shaft with blades rotates in the cylinder or tank to mix various materials into a mixture or proper consistency. The self feeding mixer will introduce the working principle of the mixer: the mixer is determined by multiple parameters, and it is impossible to describe the mixer with any one parameter. Shaft power (P), blade flow (Q), pressure head (H), blade diameter (D) and mixing speed (N) are the five basic parameters describing cement mixer trucks. The flow rate of the blade is proportional to the flow rate of the blade itself, the first power of the blade speed and the third power of the blade diameter. The shaft power consumed by the mixing truck is in direct proportion to the specific gravity of the fluid, the power criterion of the blade itself, the third power of the rotating speed, and the fifth power of the blade diameter.
For some types of blades, the discharge quantity (Q) and pressure head (H) of the blade are adjusted by changing the diameter (D) and speed (N) of the blade. The influence of large diameter blades and low speed (ensuring constant shaft power) cement mixer trucks on high flow and low pressure head, and the influence of small diameter blades on high speed production of low pressure head and flow. In the stirred tank, the method to make particles collide with each other is to provide sufficient shear rate.
From the perspective of mixing mechanism, it is precisely because of different fluid velocities that fluid layers mix with each other. Therefore, the mixing process always involves the fluid shear rate. Shear stress is a force that causes bubble dispersion and droplet breakage during stirring. It should be pointed out that the shear rate of fluid at each point in the stirred tank is uneven. According to the study of shear rate distribution, there are at least 4 shear rate values in the stirred tank. They are: in the blade area, no matter what type of pulp, when the blade diameter is fixed, the large shear rate and average shear rate increase with the increase of rotating speed.
When the rotation speed is constant, the relationship between the large average shear rate and the blade diameter is related to the pulp shape. When the rotating speed is constant, the large shear rate of the radial blade increases with the increase of the blade diameter, while the average shear rate is independent of the blade diameter. These blade shear rate concepts require special attention in the design of the scale-up and downsizing of the agitator. Compared with large cylinders, small cylinder cement mixers are generally characterized by high speed (N), small blade diameter (D) and low tip speed (ND), while large cylinder self loading mixers are generally characterized by low speed (N), large blade diameter (D) and high tip speed (ND).