Structure and Classification of Twin Screw Extruder

Twin-screw extruder consists of gear, feeding device, barrel and screw several parts, the role of each part and single-screw extruder is similar. The difference with the single-screw extruder is that the twin-screw extruder has two parallel screws placed in the same barrel.
There are many different forms of twin-screw extruder, the main difference is that the screw structure is different. Twin-screw extruder screw structure than the single-screw extruder is much more complex, this is because the twin-screw extruder screw, such as the direction of rotation, the degree of engagement and so on.
Commonly used in the extrusion of PVC profiles of the twin-screw extruder is usually closely intermeshing and non-rotating screw, a few also use the same direction of rotation twin-screw extrusion, but generally only at low speeds, at about 10r / min Range. The high speed intermeshing co-rotating twin screw extruder is used for mixing, venting granulation or as a continuous chemical reactor with a maximum screw speed in this range of 300-600 rpm. Non-intermeshing extruder and intermeshing extruder conveying mechanism is quite different, relatively close to the single screw extruder conveying mechanism, the two are essentially different.