Single Screw Extruder Knowledge-Part 3-Capacity&System Consist

Single Screw Extruder Knowledge-Part 3

The production capacity of the extruder is mainly related to the screw diameter, the screw speed, the length of the homogenization section, and the groove depth. The calculation of the extruder production capacity using the theoretical formula is complicated and can be calculated by means of the following empirical formula.

                     When the screw diameter is >90mm

                     Q=0. 0ID³NK

                     When the screw diameter is ≤90mm

                     Q=0.66D^2.5

                     Q-Capacity, kg／h

                     K-Empirical discharge factor, usually we use 0.3-0.7, use the smaller value when under the higher speed.

                     D-Screw diameter, cm

                     N-Rotating speed,r/min

The extruder is mainly composed of screw, barrel, heating and cooling system, transmission system and control system.

Heating System

The heating system for an extruder usually means the barrel, connect flange and die head heating.

Heater elements have different materials and shapes, usually like a ring or panel. It’s material includes High-efficiency ceramic, mica, cast aluminum, cast copper, electromagnetic, stainless steel, etc.

In daily working, the ceramic heater and cast aluminum heater usually adopted as barrel heating element, the stainless steel heater adopted for die head heating.

Cooling System

The barrel cooling mainly depends on the air blowing, it means the fan. Check the below drawing will get clearly.

Please click here to check more.

Here has an important cooling which related with the extrusion capacity, it is the Hopper seat cooling system. It achieves by a water sleeve outside of the feeding section.

You may heard screw cooling before, but it mainly means the twin screw system, cause of the PVC  extrusion process need control the screw temperature.

NEXT part we will learn the transmission system of the single screw extruder, it means the Gear Box.