Filter bags made of polyester needle felt can have a special spark-blocking finish.
The purpose of this finish is to protect the needle felt from sparks which can occur in some technological processes. The best solution is securing the filter chamber through a pre-filter, a cyclone, or a special blind. If this is not possible, it is recommended to use a spark-blocking filter media.
There are several ways to produce this kind of filter media:
- admixture of carbon fibers (black color)
- admixture of pre-oxidized acrylic fibers
- a special treatment that forms a barrier between sparks and the surface of the filter media
The selection of a suitable, spark-blocking filter media can be cost-related or may be liked to likelihood or actual frequency of sparks occurrence.