The primary filters are mounted on all vacuum cleaners and trap all forms of common dust, even the finest particles; There are different types of primary filters:
- Bag filters
- Star filters
- Cartridges (used as primary filters allow the industrial vacuum to run continuously without stopping for the filter cleaning)
These filters can be in L and M class for the collection of hazardous dust and they can be in different media for the different applications such as for example in PTFE (thanks to the PTFE membrane, dust falls down easier during teh filter cleaning and doesn't penetrate the filter material) or Nomex® (to be used in case of hot material).