Mixed machinery is a machine that uses mechanical force and gravity to mix two or more materials evenly. Hybrid machinery is widely used in various industries and daily life. Mixing machinery can combine a variety of materials into a uniform mixture, such as cement, sand, gravel and water mixed into concrete wet material, can also increase the material contact surface area to promote chemical reactions, but also can accelerate physical changes, such as granular solute added to solvents, through the role of mixing machinery to accelerate dissolution and mixing.

Commonly used mixing machinery is divided into gas and low viscosity liquid mixer, medium and high viscosity liquid and paste mixing machinery, thermoplastic material mixer, powder and granular solid material mixing machinery four categories.

Gas and low viscosity liquid mixing machinery is characterized by simple structure, no rotating parts, low maintenance and maintenance, low energy consumption. This kind of mixing machinery is divided into four kinds, such as air flow mixing, pipe mixing, jet mixing and forced cycle mixing.

Mixing machinery of medium and high viscosity liquids and pastes generally has a strong shearing effect, thermoplastic material mixers are mainly used for mixing thermoplastic materials (such as rubber and plastics) with additives, powdered, granular solid material mixing machinery is mostly intermittent operation, but also includes both mixing and grinding machinery, such as wheel mill.

Mixing requires that all materials involved in the mix be evenly distributed. The degree of mixing is divided into ideal mixing, random mixing, and completely unmixed states. The degree to which various materials are mixed in the mixing machine depends on factors such as the proportion, physical status and characteristics of the material to be mixed, as well as the type of mixing machine used and the time the mixing operation lasts.

The mixture of liquid mainly depends on mechanical agitator, air flow and the jet of the liquid to be mixed, so that the material to be mixed is stirred, in order to achieve even mixing. Stirring causes some liquids to flow, and the flowing liquid pushes the liquid around it, resulting in a circulating fluid flow in the solution, the resulting diffusion between the liquids is called the main diffusion.

When the flow rate of the liquid caused by agitation is very high, the shearing effect occurs on the interface between the high-speed liquid flow and the surrounding low-speed liquid flow, resulting in a large number of local vortex. These vortexes quickly spread around, and more liquid is rolled into the vortex, and the disordered diffusion that forms in a small range is called vortex diffusion.

The main diffusion and vortex diffusion caused by stirring increase the surface area of molecular diffusion between different liquids and reduce the diffusion distance, thus shortening the time of molecular diffusion. If the viscosity of the liquid to be mixed is not high, it can be randomly mixed within a short stirring time, and if the viscosity is high, a longer mixing time is required.

For liquids with different densities, compositions, and insolubles, the shearing effect and intense turbulence produced by stirring tear the dense liquid into small droplets and distribute it evenly into the main liquid. The flow rate of the liquid produced by stirring must be greater than the rate at which the droplets subside.

A small amount of insoluble powdered solids and liquid mixing process, and density components, the same mixing of insoluble liquids, but stirring can not change the particle size of powdered solids. If the premixed solid particles do not make it sink less than the flow rate of the liquid, no matter what mixing method is used, it will not form a uniform suspension.

The mixing of different pastes is mainly to mix the material to be mixed repeatedly and make it subject to pressure, scuffle, squeeze and other actions produced by the strong shearing effect, and then after repeated merger, pinching, and finally reached the required degree of mixing. This blend is difficult to achieve the ideal mix, only random mixing. Powdered solids are mixed with a small amount of liquid as pastes, and their mixing process is the same as that of paste materials.

Different thermoplastic materials and thermoplastic materials mixed with a small number of powdered solids, need to rely on strong shearing, repeated kneading and pinching, in order to achieve random mixing.

Well-fluid granular solids are mainly mixed by the swing of the container itself, or by the action of moving parts in the container, repeatedly flipping, mixing and mixing, and this material can also be used by airflow to produce verso or turbulence to achieve mixing. The vortex or turbulence of solid particles is not easy to produce vortex, the mixing speed is much lower than the mixture of liquid, the degree of mixing can generally only reach random mixing.

Poorly mobile particles or powdered solids that adhere to each other often require mixed machinery with mechanical flipping and pressure, and other movements.

The moving parts of the mechanical agitator will also have shearing effect on the liquid when rotating, and the liquid will also be subject to shearing when it flows through the wall of the machine and the various fixed components installed in the container, which will cause many local vortex diffusion.