Extruder Feeding Systems

Getting dry blend to the extruder in the same condition it left the mixer matters as much as the mixing itself. If feeding stops and starts, extruder load fluctuates; if the blend separates on the way, the homogeneity achieved in the mixer is lost. Erk PVC Makine feeding systems convey mixed raw material through a single line or to each extruder separately, with continuous feeding. Transfers of other raw materials can be handled in the same way.

Flexible spring feeding (Flexcom)

Flexible feeding moves material with a spiral spring rotating inside a flexible tube. Because the route itself can bend, material can be carried along a more flexible path than with a screw system. It offers alternative solutions in tight spaces and where the line has to pass between columns and equipment, and it has a robust build.

Screw conveyor

The screw conveyor is made to standard pipe diameters. Depending on the raw material, the screw can be stainless or black (mild) steel. A special flight design lets it feed vertically, at an angle or horizontally. It is the usual choice where a fixed, rigid conveying route is wanted.

Air conveying

Air conveying is used to move granules. The system is installed together with a vacuum system, air filter and blower. It gives a flexible arrangement where conveying distances are long or granules have to be distributed to several points. For filtration on the air side, see jet filters and auxiliary equipment.

Choosing the right system

Powder dry blend and granules behave differently in transit. Fine powders carried by air call for care over separation and filter load, while mechanical conveyors move material inside a closed channel. That is why spring and screw systems are the first options for powder blends, and air conveying for granules.

The main factors are the type of material (powder or granules), conveying distance and height difference, obstacles along the route, the number of extruders and the hourly demand. A feeding line normally starts at the outlet of the heater–cooler mixer, so planning both together is the soundest approach. On lines such as PVC drain pipes, where several extruders run on the same blend, decide early whether a single shared line or separate lines will be used. See turnkey PVC mixing line for dosing, mixing and feeding planned as one project, and feeding systems for the full range.