Paddle mixer refers to a mixing device that uses the rotating stirring blade to perform mixing. There are two types: flat paddle type and inclined paddle type. The flat paddle agitator consists of two straight paddle blades. The ratio of the diameter of the blade to the height is 4-10, and the circumferential speed is 1.5-3m/s. The resulting radial liquid flow velocity is relatively small. The two blades of the oblique paddle agitator are turned by 45° or 60° in opposite directions, thus generating an axial liquid flow. The paddle agitator has a simple structure and is often used for mixing low-viscosity liquids and dissolving and suspending solid particles.