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Twin screw extruder granulator in combination with two forms of barrel liner
May 31, 2018

In the same direction parallel twin screw extruder granulator, its combination barrel inner liner has two forms, one form is two bimetal form C-shaped bushes butt joint into the inner hole of the barrel, The form can protect the barrel; in the other form, an elliptical integral bushing is inserted into the bore of the barrel.


Both types of barrel liners in twin screw extruder granulators have their own characteristics. A bimetal C-type bushing refers to a layer of alloy with a thickness of about 1.5 mm on the inner wall of the barrel, and then A bimetal bushing that cuts into a "C" shape under the center distance condition is satisfied.


The combined barrel of a typical parallel twin screw extruder granulator uses a C-type bi-metal bushing. Its characteristic is that it is relatively wear-resistant. The standard hardness value of the alloy is HRC 58-64. If there are two bimetal C-shaped bushings, they are usually lined high into the bore of the barrel without welding, and there are naturally two gaps at the upper and lower portions of the joints, respectively.


However, as the use time goes by, the gap is increased due to gradual wear of the alloy layer, and at the same time, the alloy layer is gradually fatigued at the edges. Not only will the upper and lower gaps increase the space for retention of polymer materials, it will also cause the material to accumulate in the gaps and be carbonized more and more under the effect of back pressure.


In view of this, for the highly wear-resistant twin-screw extrusion granulation machine, the integral elliptical inner bushing is used as the combined barrel working liner, in order to optimize the service life of the barrel. The use of an elliptical inner bushing has three distinct advantages over the use of two C-type bi-metal bushings.


On the one hand, there is no gap in the twin screw extruder granulator because the elliptical sleeve is completely sleeved. The user does not need to worry about the retention of macromolecule material at the two upper and lower gaps of the bushing. There is no dead zone in the barrel and there is no internal contamination of the material. The threat and excellent self-cleaning property, on the other hand, also avoided the stress of two acute angles at the upper and lower parts of the bush after the docking of the two bimetal “C” shaped bushings, and the threat of brittle iron-based alloy sharp corners and mouthwashes was reduced.


In addition, the elliptical integral sleeve will be more advantageous for some high-end parallel twin-screw extrusion granulators, especially when the equipment is in a higher screw torque, higher screw speed and higher working back pressure conditions, the user can be more Safe operation of the machine.

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