Cause:
When using a raw material that emits gases (VOC) or water vapor (hydroscopic), the cylinder must have a vent hole. This opening is sensitive to contamination and dirt due to its physical structure and the fact that shear stresses that apply on other areas of the screw.
This is why it is important to create the cleaning and shear stresses required for cleaning.
Solution:
We recommend sealing the vent during the general cleaning process using a suitable cover, in order to maintain the cleaning pressures that are required in the cylinder. In the even that it is not possible to seal the vent opening, expect a pressure drop in the cylinder volume during the cleaning process, due to the material foaming through the ventilation opening.
To clean the ventilation opening, fill it with cleaning material by manually inserting a number of grains. The vent will clean during the extruder cleaning process.
