Many cartridge dust collectors today are equipped with a bank of filters installed downstream of the clean air discharge. These systems are known by a variety of names — safety monitoring filter, secondary filter, after-filter and safety filter being the most common terms.
Simply stated, these filters are designed for use when you want to recirculate air through the plant downstream of the collector. In reality, choosing and using safety monitoring filters is a bit more involved than that. Here are answers to the 10 most common questions.