Principle of Operation and Maintenance Issues of Co-Rotating Parallel Two Screw Extruder

What is the working principle of the two screw extruder?


Due to the small center distance of the two screw extruder, it is impossible to use large-diameter thrust bearings. The bearing capacity of thrust bearings is related to their diameter, with larger diameters having greater bearing capacity.


This contradiction is usually resolved by connecting several small-diameter thrust bearings in series to jointly withstand strong axial forces. If this method is adopted, it must be ensured that each thrust bearing bears the same load evenly. Otherwise, the bearing that bears the large load will be damaged due to overload, and the load it should bear will be added to other bearings, causing continuous damage, ultimately leading to the failure of the entire mechanical equipment.


The conical two screw extruder has a larger center distance between the two output shafts of the transmission gearbox due to the angle between the two screws. Two larger thrust spherical roller bearings are arranged alternately front and rear in the gearbox to prevent the axial force generated by the head pressure.


It can be seen that the transmission system structure of the parallel two screw extruder is more complex than that of the conical two screw extruder. Compared with the conical two screw extruder, the manufacture and maintenance cost of the gearbox is higher and the maintenance is more complex.


Maintenance of the parallel two screw extruder


Maintenance issues: The parallel two screw extruder should be placed in a location with good air circulation to ensure that the heat generated during each operation is adequately released and to allow the equipment to decompress fully. Lubricating grease should be introduced into the equipment on time to ensure the lubrication between rolling bearings. Regular maintenance of the cooling circulating water of the equipment is necessary. During operation, the cooling circulating water should be in a slow-flowing state. Otherwise, regular inspection and maintenance are necessary.


Before using the parallel two screw extruder equipment, it can be preheated and gradually put into operation to ensure the sufficient rotation of the transmission gears and to quickly enter into operation, especially in winter when heating is essential.


During operation, the screw speed should be slowly rotated before accelerating, and the current meter should be observed throughout the entire process. There is also a safety hazard to be aware of. During actual operation of the equipment, operators or other workers should not stand directly in front of the extrusion inlet, as the temperature at the inlet is high, and to prevent burns and other corresponding safety accidents.

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