Determination of Fractional Efficiency and Loading of Compressed Air Filters in Overpressure up to 7 Bar (PPT)

摘要

The test of fractional efficiency of compressed air filters is described in ISO 12500. For the determination of the fractional separation efficiency a particle counting and particle size measuring device, a so-called optical aerosol spectrometer, is generally used. In this case, one must ensure that the complete measuring chain is laid out isobaric to avoid changes of the test aerosol with regard to its particle size distribution and concentration. The aerosol mass flow as defined in ISO 12500 is much too low to bring the filter into a steady state operation within a time frame which ensures as well an economic filter test. If a higher aerosol concentration is used for loading of the filter, the same fractional efficiency must be measured at the same differential pressure of the test filter. Especially for this application Palas~R has developed the new filter test system DFP 3000 which allows the loading and detection of fractional efficiency of compressed air filters in overpressure up to 10 bar. The main parts of this system are: 1) The new aerosol generator PLG 3000 for the detection of fractional efficiency according to ISO 12500. 2) The new aerosol generator AGK 3000 for the defined loading at high mass flow of oil droplets 3) The optical aerosol spectrometer welas ? digital 3000 P with automatic control of the sampling air flow through the Sensor. In this paper we will describe the working principle of this new system and show results concerning the comparison of compressed air filter under different conditions.