1. Intended for melting, homogenization and packing of the initial material - polyethylene low and high pressure, polypropylene, PVC. It is a component part of every extruder line - for pipes, flexible tubes, blown foil, profiles, isolation of cables, plastics granulation ... etc.

2. Description

The extruder has the following basic units:

- Frame
- Cylinder
- Screw
- Reducer
- Electric equipment
- Cooling system
- HeatingĀ  system
- Electric motor

Frame - upon it mount the basic units.
Cylinder - along with the feeding unit (hopper) has the function to supply the material into the turns of the rotating screw and along with it to do the plasticization and its ejection through the profiling head .The demands are the following: adequate mechanical strength with a view of obtaining high pressures at extrusion; adequate high smoothness upon the inner surface; high wear resistance and corrosion resistance;
Screw - mount it in the cylinder and through the shaft of the bearing unit set in motion. The screw surface is grinded and nitrited, which increase considerably the productivity and wear resistance.
Reducer - filled with cylindrical gear wheels with sloping teeth. The bodies of PSH-45, PSH-63, PSH-90 have a welded unit, while PSH-125 -cast iron castings, put to aging and free of heat stress. The driving is going on with DC motor, which through belt drive operates the reducer. On its part it sets in rotating motion the screw.
Electric equipment - intended for control the revolutions of the electric motor and thermoregulation the heating of the cylinder.
Cooling system - intended for cooling the cylinder and the screw. The press is air and water-cooled. The cooling of the cylinder is going on through ventilators, which push in the air into casings around the cylinder. The cooling of the screw and the cylinder in the feeding zone is going on through water.
Heating system - intended for heating of the cylinder .The heaters are grouped in heating zones.
Electric motor - intended for driving of the extruder. Use DC motor with a view to lightly control of the revolutions in wide range.


3. Work of the extruder

The mounted electric motor with adjustable revolutions through belt drive operates the reducer, which on its part sets in rotating motion the screw. The initial material feed into the hopper and from there in the power zone of the screw. Through the rotating motion of the screw the material is pushed out to the forming instrument through which come out elasticized. The plasticization of the material goes on at the expense of the thermal separation, as a result of the transformation of the mechanical energy into thermal and extra quantity of heat from the heaters on the cylinder. Conditionally the cylinder and the screw in the direction of the material movement divide into 3 technological zones: feeding zone - intended for taking of the initial material; homogenizing - where take place the plasticization of the material and the transformation of the mechanical energy into thermal; injection - where the plasticized material injects with high pressure into the forming instrument.


©1992 Desislava 20 Granulators Ltd.