Page 26 - Vol.10

Tech
Notes
技術專文

Figure 4. Calculated penetration of particles through the unipolar Figure 5. Experimentally determined charging efficiency
corona charger

1.0 1.0

0.8 1
Calculated Particle Penetration 0.6 Charge/ Particle [e] 0.1 Experimental data

0.4

Fuchs, Nt = 4x10 m s
0.2
Fuchs, with losses
y = 0.015*d
0.0 0.01
10 100 10 100
Particle Diameter [nm] Particle Diameter [nm]

Figure 6. Compared with of condensation particle counter (CPC) Figure 7. Compared with of condensation particle counter (CPC)

1x10 40000
2
2
y = 0.82* x ; R = 0.90 y = 0.87* x ; R = 0.97
b b
8x10 30000
miniature DiSC number [cm ] 6x10 miniature DiSC number [cm ] 20000

4x10
10000
2x10

0 0
0 2x10 4x10 6x10 8x10 1x10 0 10000 20000 30000 40000
CPC number [cm ] SMPS number concentration[cm ]

(MAU) and fan filter units filters. number of particle counter (CPC) estimate ion concentration of
If the size distribution and surface are separately independent, thus the Nit=7.5x1012m-3 with a maximal
activity of the particles do not value of DAVE,S could be a reliable corona voltage of ~5.5kV. The actual
change severely, the change in the index of the diameter of the particle charging efficiency is measured by
total particle number concentration shown as Figure 3. empirical calibration experiments,
won’t inf luence the numerical which shows high degree of statistic
value of DAVE,S. But it should be correlation, in spite of a noticeable
mentioned that on the calculation Diffusion size classifier charger loss down to about 20nm,
base, a shift of the characteristic M. Fie r z et a l . d e sig ned a nd which will make the instrument to
diameter of the particles towards calibrated a miniature diffusion underestimate the particle numbers
larger diameter, it will represent an s i z e c l a s s i f ie r for f ie ld u s e , smaller than this size.
increase in DAVE,S value. they shrunk the size down to
4x9x18cm,which stores data to a Another key component is the
N. Bukkowiecki et al.,’s research secure digital memory card (SD- electrometer, which measures
shows good correlation between card) and powered by built in current in a very low level of the
[4]
DAVE,S(A) and DAVE,S(SMPS) rechargeable battery . The key charged nanoparticles. Thus it
in the particle diameters range components of this instrument is very sensitive and vulnerable
from 20nm to 60nm since the are unipolar corona charger and to the zero offset and noises. The
measurement of the diffusion the electrometer. Unipolar corona main inaccuracies coming from
charging sensor active surface and charger is characterized by an zero offset error is the temperature

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