Plymovent Filters FAQs
Straight answers to the questions people ask most when choosing replacement filters for welding fume extraction systems.
How do I know when a filter needs replacing?
Most units have a pollution indicator or pressure gauge that shows when the filter is loaded. Other signs are weaker suction at the hood, more frequent cleaning cycles, and more dust or smell in the workshop.
Change the filter when the indicator says so or if airflow cannot be restored by cleaning. Keep a record of change dates to help plan.
What is the difference between cartridge, cassette and bag filters?
These are different filter formats, and the names vary between makers. Cartridge filters are usually pleated tubes giving a large filtering surface in a compact space, and are often cleaned by pulses of air. Bag filters are fabric pockets, and panel or cassette types are flat elements.
The unit is designed around one format, so the data plate and manual for your own machine will tell you which type and size fits. Each has its own fitting and cleaning method.
What does a pre-filter do?
A pre-filter catches larger particles before they reach the main filter, so the main filter lasts longer. Some pre-filter stages also help reduce the chance of sparks reaching the main filter, but only if the maker designed them for that purpose.
Pre-filters are normally quicker to change than main filters and may need cleaning or replacing more often. Check the manual for your own unit for the type to use and how often to check it.
What is an activated carbon filter used for?
It adsorbs gases, vapours and odours that ordinary particle filters cannot catch, for example from some solvents, coatings or certain processes. It is usually an additional stage after a particle filter.
Carbon filters become saturated and need replacing on a schedule based on the contaminants and use. They do not trap solid fume particles.