The filter is an integral part of each device for providing clean conditions, so it needs to be checked if it provides specific particle retention. After completing the test, we make a report. The test is carried out in accordance with ISO 14644-3 and two methods.

 

1. Particle Particle Method (DPC) method:

A prerequisite for starting the test is the correct air flow through the filter. We artificially contaminate the air before the filter using an aerosol generator and test oil. We measure the concentration of particles before the filter and determine the maximum number of particles that can penetrate the filter (maximum allowable particle penetration). Prior to the test we have to determine the measurement time, which is calculated according to the filter dimensions, test probe diameter, scanning speed. Calculated time is then rounded to whole minutes. The frame and the entire surface of the filter are scanned with an isokinetic probe. The particle counter prints the results on the thermal paper, which is later attached to the final report. An acoustic alarm on the particle counter signals the presence of particles in the air. Once we determine the location of a leak, we must further examine this part locally. In certain cases (filters installed in channels), filter scanning is not possible. In that case, measurements are performed on the intended connections. If the filter exceeds the maximum allowable particle penetration, it is necessary to improve the fitting, eliminate critical leaks or replace the filter with a new one.

 

2. Method using a photometer:

The perquisite for starting the test is the also the correct air flow through the filter. A particle generator that creates a mixture of heated test oil and compressed nitrogen in the form of smoke is used. The air before the filter is artificially contaminated. The photometer is prepared and calibrated in accordance with the manufacturer's instructions. The frame and the entire surface of the filter are scanned with an isokinetic probe. In certain cases (filters installed in channels), filter scanning is not possible. In these cases, measurements are made on the intended connections. If the filter exceeds the maximum allowable particle penetration, it is necessary to improve the fitting, eliminate critical leaks or replace the filter with a new one.

We use the professional measurement equipment of renowned manufacturers: Lighthouse, TSI, Topas, ATI. All equipment is calibrated annually.

 

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