Internal mixer is a high-intensity intermittent mixing equipment developed on the basis of open mixer.Internal mixer is a mechanical device equipped with a pair of rotors of specific models and rotating in correspondence. Under closed conditions with adjustable air temperature and pressure, it plasticizes and mixes polymer materials in an intermittent manner. It includes internal mixer, rotor, rotor sealing device, feeding and pressing machine equipment, transmission device and machine base. The whole equipment is compact and fully functional, which not only improves production efficiency but also reduces energy consumption. It is an indispensable and important part of modern industry.

Working Principle of Internal Mixer

During operation, the two rotors rotate relative to each other, and the material introduced from the feed port passes through the roller gap under the extrusion and shearing of the rotors. After contacting the sharp edge of the bolt under the top, it will be divided into two parts, which return to the gap again along the front and rear walls and the gap between the rotors.

During the process of going around the rotor, the material is in a state of shearing and friction everywhere, which makes the temperature of the rubber material rise rapidly and the viscosity decrease, thereby improving the wetting ability on the surface of the compound, and achieving full contact between the rubber and the compound surface. During the mixing process, the particles of the compound follow the mixed colloid, passing through the gap between the rotors, the gap between the rotor and the upper and lower top rings, and the inner wall of the mixing chamber, and are sheared, so that a circle of tensile and deformed rubber rings are formed around the mixed body, thereby achieving the purpose of breaking.

At the same time, the ridges on the rotor make the rubber material move along the axial direction of the rotor, playing a stirring and mixing role, so that the compounding agent is evenly mixed in the rubber material. The compounding agent is repeatedly sheared and crushed, and the rubber material repeatedly deforms and recovers its deformation. The continuous stirring of the rotor ridges makes the compounding agent dispersed evenly in the rubber material and achieve a certain degree of dispersion.

Because the shearing force on the rubber during mixing in the internal mixer is much greater than that in the open mixer, and the mixing temperature is high, the mixing efficiency of the internal mixer is much higher than that of the open mixer.

Basic structure of internal mixer

1. Mixing chamber: This is the main part of the internal mixer, usually consisting of two semicircular rotors and a closed chamber. The rotors in the mixing chamber rotate to mix and process the materials.

2. Rotors: Internal mixers are usually equipped with two rotors, which can be zigzag, spiral or other specific shapes. The rotors rotate in the mixing chamber to achieve the effect of mixing and shearing.

3. Drive device: The device responsible for driving the rotor to rotate. Common drive devices include motors, reducers, etc.

4. Feeding device: A device for adding raw materials to the mixing chamber. It can be in the form of a hopper, conveyor belt, etc.

5. Discharge device: A device for discharging the mixed material from the mixing chamber. Usually includes a discharge port and related control systems.

6. Temperature control system: In order to control the temperature during mixing, the internal mixer is usually equipped with heating and cooling devices to ensure that the temperature during mixing meets the requirements.

7. Hydraulic system: Used to control the opening and closing of the mixing chamber, usually including a hydraulic cylinder and related control systems.These components work together to enable the internal mixer to efficiently mix and process a variety of materials.

Internal Mixer Application

Internal mixer (Banbury mixer) is a kind of equipment used for mixing polymer materials such as rubber and plastics, and is widely used in rubber, plastic, chemical, pharmaceutical and other industries. Its main function is to form a mixture of different ingredients (such as rubber, plastic resin, filler, additive, etc.) uniformly through high temperature and high pressure to make it a material with specific properties.

1.Rubber industry
Tire manufacturing: Internal mixer tires are widely used in the production process to mix rubber ingredients such as natural rubber, synthetic rubber, carbon black, modifiers, etc. to enhance the wear resistance, heat resistance and elasticity of rubber.
Seals and rubber products: used to produce various seals, buffers, buffers, etc.

2. Plastics industry

Plastics: Internal mixer is used to produce engineering plastics and modified plastics, such as enhanced UV, extended polyethylene, etc., by uniformly mixing plastic resin with additives and fillers to improve the physical and chemical properties of plastics.

Masterbatch production: Internal mixers are used to mix pigments with plastics to produce masterbatches for coloring.

3. Chemical Industry

Mixing aids: In the chemical industry, internal mixers are used to mix various additives such as plasticizers, stabilizers, antioxidants, etc. to improve the performance of the product.

Resins: Internal mixers used for precision mixing and blending of thermosetting resins help in the preparation of composite materials.

The main advantage of the internal mixer is its mixing ability. It can quickly deliver uniform mixing in a short time and can withstand high temperatures and pressures. Therefore, it plays an important role in the production of products with high requirements for mixing uniformity.