Dado Lab QB1 - Qb1-D; Dilution Sampler; Flowrates Definition; The Sampling Flowrates Depends on Tubes Used

ENGLISH | 15
Flowrates denition
e sampling owrates depends on tubes used:
0.4 l/min - large tubes (600 mg)
1.0 l/min - jumbo tubes (1000 mg)
Set the owrate on LINE1 owmeter
Calculate dilution owrate
e owrate depends from humidity of duct fumes,
the ambient temperature and must avoid reaching
the condensation point in the sampled gas.
e graph on page 17 shows the dilution owrate
to set on QB1-D sampler.
1. Find the RD value (dilution ratio) nding on X axis
the rw of duct gas (ratio by volume of the vapor
content e.g. 10% of vapor equals 0.1 of rw).
2. Find the corresponding cur ve on ambient tempera-
ture and read on Y axis the RD value.
3. Multipling RD value with sampling owrate
chosen, you nd the dilution owrate to use
Dilution sampler
QB1-D is a special version of the QB1 V2x5DC in
which the owrate of the secondary pump delivers
the dilution air instead of sampling.
is particular version is dedicated to VOCs
sampling in accordance with the EN13649 which
requires the dilution of the sample with, previously
cleaned and dehydrated, ambient air introduced in
the dilution chamber of the probe (HP1).
e dilution sampling oers the advantage of im-
proving the adsorbing eect on the sampling tube
thanks to the lower temperature and dehydrated gas
stream conditions. is allows also to use only one
charcoal tube and to greatly reduce the stripping
eect, usually due to high temperatures and water
presence.
To set the dilution rate, e.g. 1:4, regulate the total
sampling owrate, 1 lt/min for instance, and the
dilution owrate, 0.8 lt/min, the dierence of the
two values, 0.2 lt/min will be the resulting sampling
owrate.
e sampled volume will be given by the dierence
between the total sampled and the dilution volumes.
7
QB1-D