TSI Instruments 3079A, Operation And Service Manual, Page: 29 / 39

Appendix
Model 3079A 7-3
7. Remove absolute filter from isokinetic sampling probe SYS 529, put probe underneath the filter to
be tested, switch on the pump, carry out leak test and clean air measurement.
8. Switch off the aerosol generator; blank off aerosol inlet of the tested unit.
9. Summarize the results in a report.
The scanning velocity for the leak test depends on the filter outlet velocity, the cross-section
dimensions of the sampling probe, and the particle concentration of the test aerosol.
It is shown in the diagram in Figure 10 for one of the rectangular TSI sampling probes (according to
DIN EN ISO 14644).
Estimating the Particle Concentration of the Test Aerosol
Calculation Formula for Two Types of Laminar Flow Boxes
For both types of laminar flow boxes the particle number concentration in the air can be calculated
with formula (1). The particle number concentration of the surrounding air is neglected in this formula.
total
AG
AG
total
AG
test
V
V C
V
N
C






(1)
If the particle number concentration of the surrounding air is to be considered, other formulas for the
two types of laminar flow boxes must be used [formula (2) and (3)].
Model I:
total
AG total
room
AG
AG
total
room AG
test
V
) V V ( C V C
V
N N
C












(2)
Filter
Typ I Typ II
V
AG
C
AG
V
total
C
room
C
test
V
total
C
clean
V
AG
V
LAF
C
test
V
LAF
C
clean
V
room
C
room
V
AG
C
AG
V
total
C
test