The bag filter
Due to increasingly restrictive limits for atmospheric emissions together with new technologies for greater filter efficiency, problems related to environmental impact have now been greatly simplified.
Materials collected in the filter, commonly known as filler (even though this is an improper use of the term, since the material isn’t always screened through the 0.063 mm screen), is collected at the bottom by an auger, then conveyed into a surge hopper, ready to be weighed and re-fed into the mixer in the correct quantity.
The filler plays a fundamental role in regulating the asphalt adhesion and improving the bitumen binding to the aggregates.