Cassette filters Infa-Micron MKR are particularly suitable for demanding processes of the chemical and pharmaceutical industry, where dusts occur, that are hazardous to health or toxic, e. g. API (active pharmaceutical ingredients). With applications of this kind, lowest residual cust contents down to 0.001 mg/m³ and the secure protection of staff is requested.

The new generation of the series Infa-Micron MKR impresses the market already with more ease of operation, increased gas tightness, easier cleanability inside and outside as well as less construction height.

In order to evaluate the usability in case of explosion, the cassette filter was now under a safety-related review by FSA*. The classification in dust explosion classes ST 1 to ST 3 gives an information about maximum rate of pressure velocity increase (KSt value) in bar m/s:

• St 1: > 0 to 200 bar m/s
• St 2: > 200 to 300 bar m/s
• St 3: > 300 to m/s

The explosion tests with the Infa-Micron MKR were executed as well with combustible dust as with a combination of combustible dust and combustible gas (hybrid mixture). The tests on the filter showed no deformation at all and confirm the high mechanical strength of the Infa-Micron MKR against explosion pressures. The cassette filter was authorised for KSt-values up to 600 bar m/s.

If occurrence of explosion can‘t be excluded, there are constructive safety measurements for the Infa-Micron MKR available, like pressure shock resistant design or additional equipment for explosion suppression.

Extensive dust exposition measurements (containment) at the Infa-Micron series MKR and MPR took place at the same time. The tests regarding filter change and dust discharge confirmed that these filter series comply with highest safety standards when processing toxic and highly effective substances.

(*Forschungsgesellschaft für angewandte Systemsicherheit und Arbeitsmedizin mbH)