Automotive Filters

Back in the early 80's, MNR realized that FPCP media (Open Cell Reticulated Polyurethane Foam) was far better suited for air filtration than the paper filters that were prevalent at that time. The development of this special foam represented a major advancement in high technology air filtration. Foam air filters combine great airflow capacity, huge dust holding capacity and very high filtration efficiency even for particles in the range of 1 micron. FPCP media is a honeycomb of tiny interlocking cells of relatively uniform size which creates a tortuous path for the dust particles to take. Each passageway, 16-25mm long, acts like hundreds of very small filters all connected to one another. This is the reason why FPCP is referred to as "depth loaded" filters. Dust passes through the "depth" of the FPCP media getting trapped on the struts of the FPCP media. Oil is used to coat the struts of the FPCP media to act as a "tackyfier" holding the dust firmly once it has hit a strut.

 

 

 

Industrial Filters

One cubic meter of air consists of more than 9 million particles in the range of 0-0.5 microns occupying 1 % of the volume but representing 98.5 % by Particle Count. Just 500 particles in the range 10-30 microns occupy 30 % of the volume but represents only 0.005 % by Particle Count. No one filter media can effectively handle a conglomeration of such particles: hence the importance of “PROGRESSIVE FILTRATION”

Progressive Filtration is a method where considerable life extension of a filter can be obtained by creating a `PROGRESSIVE STRUCTURE' of the filter media with differing pores arranged behind one another so as to produce a uniform reduction in the porosity towards the clean air side.

We, at MNR, have successfully developed technically competent and competitively priced solutions for all customer requirements. This has made MNR synonymous with filtration solutions amongst many industry majors across the country.

The latest revision of ASHRAE 52.2-1999 establishes a Minimum Efficiency Reporting Value (MERV) system that can be applied to various air filtration devices. After the test is completed, the filters' minimum efficiency values at various particle sizes are recorded. These efficiency values are then used to assign an overall MERV (1-20). The MERV system makes it easy to compare the efficiencies of most filters at a glance. ASHRAE 52.2-1999 is designed not to replace but to complement the older standard ASHRAE 52.1-1992.

ASHRAE 52.1-1992 is based on average efficiency and average synthetic dust weight arrestance. This does not tell us how efficient it is at removing respirable particulate or mold spores. Under ASHRAE 52.1 there is no way to know, unless the manufacturer can provide additional data.

ASHRAE 52.2-1999 establishes a new controlled method of laboratory testing and provides minimum efficiency data versus average efficiency data. The new method will show a filter's minimum performance through its life. Under ASHRAE 52.1-1992 the only available data are based on average efficiency, a less stringent measure of performance. The new standard measures performance of air filters on its ability to remove particles of specific size. As the test is conducted, a particle counter measures the number of airborne particles of 0.3 to 10 microns.

The European Normalization Committee, (CEN or EN in short) for air filters also covers the gamut of filters from the Pre Filters to HEPA (High Efficiency Particulate Air), ULPA (Ultra Low Penetration Air) to SULPA (Super Ultra Low Penetration Air). The ASHRAE test methods listed above are referenced in many European countries. The Eurovent classification of filters, now in use in Europe, established filter categories based on the ASHRAE Test method.

The Efficiency of Pre and Fine filters are determined by the EN 779 standard, while the efficiency of HEPA and ULPA filters are determined by the EN 1822-5:2000 standard. EN 1822 has been prepared by the technical committee CEN/TC 95. The difference between this standard and the previous standard lies in the technique used for the determination of the overall efficiency. It is based on particle counting at the Most Penetrating Particle Size (MPPS) in the range of 0.15 micron to 0.30 microns. It also allows ULPA filters to be tested, which is not possible with the previous test methods because of their inadequate sensitivity. The tests can be carried out using either a mono-disperse or poly-disperse test aerosol.