TSI Instruments 3079A, Руководство по эксплуатации и обслуживанию, Страница: 19 / 39

5-1
5 Applications
Testing HEPA/ULPA Filters
A very important application for the Model 3079A is the testing of high efficiency filters, and the
verification of cleanrooms and laminar flow boxes.
The produced aerosol was analyzed by extensive measurements by means of a Scanning Mobility
Particle Si
zer™ System; TSI Inc.). The resulting particle size distribution is shown in the following
diagram.
0
1E+6
2E+6
3E+6
4E+6
5E+6
6E+6
7E+6
0 0,2 0,4 0,6 0,8
Particle size, µm
C
o
n
c
e
n
tr
a
ti
o
n
,
P
a
rt
ic
le
/c
m
³
Figure 5 : Particle Size Distribution of a DEHS Aerosol Measured by the Scanning Mobility Particle Sizer
The produced DEHS aerosols features very high particle concentration (>10
7
particles/cm
3
) for particle
sizes close to the so-called most penetrating particle size MPPS (0.1...0.3µm). The particle
concentration is also sufficiently high (1.5

10
7
particles/cm
3
) in the measuring range of most optical
particle counters (0.3...0.5µm).
The following table shows the Model 3079A flow rates to adjust for various volumetric flow rates
through systems at three different particle concentrations. The particle concentrations assumed here
are well above the required concentrations as specified in the VDI 2083-3 and EN 14644-3 standards
and thereby enable the determination of the optimum scanning velocity with a sampling probe from
appropriate diagrams.