| 摘要 |
PURPOSE:To prevent the adhesion of fine particles in piping, by forming recirculation piping equipped with an ion generation part between a sample air suction part and a measuring device and polarizing the inner wall of the piping and the filter at the inlet of the recirculation piping to the same polarity as an ion. CONSTITUTION:Sample air is sucked from a sample air suction port 1 and sent to the branch point in the vicinity of the suction port 1 of sample air piping 2 by an air pump 7 to be mixed with the ion from an ion generation part 4. By this method, fine particles in sample air are charged. Because the inner walls of the piping 2 and recirculation piping 6 and a filter 5 are polarized to the same polarity with the ion, fine particles are not adhered to the piping 2 by electrical repulsive force and also repulsed by the filter 5 to be sent to a fine particle measuring device 3 and measured. The ion from the ion generation part 4 is not adhered to the piping 6, too. |
