The Columbus® filters are multilayer filters formed by the overlapping of stretched nets in fire retardant paper, joined by longitudinal seams with silicon-free yarn.
The meshes can be 5 sizes: High Capacity, Large, Normal, Small and Mini-Mesh.
The number of layers varies from 5 to 12 in the different models.
In some models the final layer consists of a polyester fibre postFilter, which allows fine separation.
Usually the rolls of paint collectors© are supplied in the untrimmed version.
The actual width varies from 100 to 120 cm.
The length of the rolls is 10 or 12 metres.
Apparent length and effective length
The length development is defined by the number of meshes per meter under regular opening conditions and is controlled at production.
The manufacturing tolerance is +/-5%.
Due to the characteristics of the paper, vacuum polyethylene packaging and variations in humidity, the rolls usually have an apparent length shorter than declared: if unrolled on a flat surface a 10 metre roll can develop from 5 to 8 metres.
In these conditions the meshes are too closed and the filter loses its characteristics of permeability and overspray accumulation capacity which make it advantageous to use.
In order to restore the mesh opening to its regular size, the roll must be stretched beyond its actual length by up to 20-25 %.
Then release the roll, which will take on a length close to the production length unless there are effects due to the change in humidity.
Once this operation has been carried out, the roll can be cut and set up.
If the cut is made at a different time and place from that of installation, the stretching operation may be necessary even before use on each individual panel.