ars 1 - fraunhofer€¦ · ars 1.0 – working principle through an inlet neutral air is drawn into...
TRANSCRIPT
For evaluations of olfactory parameters it
is still necessary to use human pannelists.
Naturally the olfactory perception between
individuals varies. Therefore several
approaches have been tried out to linearize
the pannelists responses.
An approved and reliable approach for this
is the use of a reference substance. An
unknown olfactory impression is compared
to a reference substance with regard to
its e.g. odor intensity. Besides butanol,
in some regulations acetone is used as
reference substance. For example in DIN
ISO 26000-28 the perceived intensity PI
is referred to defined concentrations of
acetone.
For evaluations using a reference substance
it is necessary to have a device, which
provides the reference substance in a
defined and reproducible concentration to
the panelists.
The ARS 1.0 was developed to accomplish
these targets. The device generates at
its outlet an acetone atmosphere in a
concentration range suitable for olfactory
evaluations. The acetone concentration can
be defined by the user. It is provided to the
panelists as long as he needs it, but not
longer than necessary to avoid contamina-
tion of the surrounding area.
So the ARS 1.0 can be used for measure-
ments according to DIN ISO 16000-28 and
ISO 16000-30 in the laboratory but also
out in the field.
ARS 1.0 – Working principle
Through an inlet neutral air is drawn into
the device. To remove possible contami-
nations from the neutral air, an air purifier
is placed in the inlet. This neutral air is the
constantly flowing main gas stream and is
regulated by a mass flow controller.
In a reservoir a small amount of liquid ace-
tone is provided. The reservoir is connected
with an airtight syringe. If the syringepiston
is pulled, air is passing through the acetone
and the saturated vapour phase is drawn
Fraunhofer Institute
for Building Physics IBP
Department Building Chemistry,
Building Biology, Hygiene
Fraunhoferstraße 10
83626 Valley
Working Group Chemistry
Dr. Christian Scherer
Phone +49 8024 643-246
Stefan Mair
Phone +49 8024 643-294
COMPETENCES IN DETAILARS 1.0
F R A U N H O F E R I N S t I t U t E F O R B U I l d I N G P H y S I C S I B P
into the syringe. The syringepiston is always
pulled up completely. If this state is reached
the device can be seen as loaded.
On demand the acetone vapour in the
syringe is ejected into the main gas stream.
For high concentrations, the syringe is
emptied faster, for low concentrations
slower.
The concentration of acetone in the satu-
rated vapour depends on the temperature.
For this reason a temperature sensor is
implemented in the device and a regression
term with regard to temperature regulates
the ejection speed of the syringe.
By switching valves in an appropriate way
it is guaranteed, that the acetone vapour
is first led to the syringe and then to the
main gas stream.
ARS 1.0 – Product properties
– Free selectable acetone concentrations
– Release of acetone on demand
No contamination of the test area