Internal mixer
DATE：2021/3/9 8:38:06 / READ： / SOURCE：This station
Internal mixer
PE breathable film equipmentInternal mixer is a kind of high strength gap mixing equipment developed on the basis of open mixer. Because the mixing chamber of the internal mixer is closed and the materials will not leak out during the mixing process, the oxidation and volatilization of the additives in the materials during the mixing process are avoided, and the liquid additives can be added. The closed mixing of internal mixer can effectively improve the working environment, reduce the labor intensity of workers, shorten the production cycle, and provide conditions for the application of automatic control technology. The earliest internal mixer was invented by Banbury in 1916, also known as Banbury internal mixer or elliptical rotor internal mixer. In 1934, the British franis Shaw company developed the Shaw internal mixer, also known as the cylindrical rotor internal mixer. Internal mixer was first used in rubber mixing and plastic mixing, and then it was widely used in plastic mixing. PE breathable film equipment www.handern.com
The mixing chamber of the internal mixer is a closed cavity with a section of ∞ shape, in which a pair of rotors are installed. There are sealing devices at both ends of the rotors to prevent materials from leaking from the rotor shaft. The upper part of the mixing chamber is equipped with feeding and pressing devices. The feeding device is composed of a bucket shaped feeding port and a flap door. The pressing device is composed of an upper pushing bolt and a cylinder, and the upper pushing bolt is connected with the piston rod and the piston. The discharging device is set at the lower part of the mixing chamber and is composed of a lower top bolt, a lower top bolt opening and closing device and a locking device. The opening and closing of the flap door, the lifting and pressing of the upper top bolt are controlled by the pneumatic system, and the opening and closing of the lower top bolt and the action of the locking device are controlled by the hydraulic system. When the internal mixer is working, the mixing chamber wall, rotor, upper top bolt and lower top bolt must be heated or cooled, so it is equipped with heating and cooling system. PE breathable film equipment www.handern.com
The heating medium is generally steam and the cooling medium is water. In order to prevent the rotor from axial movement or readjust its axial position in the mixing process, when the rotor bearing adopts sliding bearing, the axial adjustment device is generally set. When the rolling bearing is used, the axial force of the rotor is borne by the bearing. Once the clearance between the rotor and the mixing chamber wall is adjusted, it is unnecessary to set the axial adjustment device. When the mixer is working, the flap door is opened, the material is fed from the feeding port, the flap door is closed, and the top bolt presses the material into the mixing chamber under the pneumatic drive. During the working process, the top bolt always presses the material. After mixing, the lower top bolt is opened and the material is discharged from the discharge port. The discharged materials are generally added into the discharge extruder for granulation or direct extrusion into sheets. Rotor is the core component of internal mixer, and rotor structure is one of the key factors to determine mixing performance. The traditional Banbury rotor is a two edged oval rotor. Its working part is oval in any section. There are two spiral ribs on the surface of the rotor. The ribs extend from both ends of the rotor working part to the center, one is left-handed and the other is right-handed. Two ridges - long and one short, with different helix angles. There is a cavity in the center of the rotor, which can be filled with heating or cooling medium. PE breathable film equipment www.handern.com
In order to increase the mixing capacity and production efficiency, multi edge rotors, such as three edge and four edge rotors, are developed. At present, on the basis of the above rotor, many new rotors have been developed, such as the rotor with circumferential groove on the convex edge and the rotor with pin on the rotor working surface. These new rotors have outstanding advantages in reducing energy consumption, improving mixing quality and reducing mixing temperature.
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