Description Of Operation; Handling; General Information - testo 105679 Bedienungsanleitung

Relative humidity for saturated solutions
100
90
NaCl
80
70
60
50
40 MgCl
2
30
20
LiCi
10
0
0 10 20 30 40 50 60 70 °C
32 50 68 86 104 122 140 158 °F
Defined
relative
humidity
The control containers are double-walled (see dia-
gram).
The inner wall is a diaphragm (porose wall,
Diaphragm
permeable to water vapour). The outer wall is made of
transparent plastic. The saturated salt solution (NaCl
or LiCl) is located between these two walls. The water
Salt
vapour penetrates through the diaphragm into the
solutions
inner part of the container and forms an air mixture
(LiCl or
NaCl)
with a specified water level. This corresponds to a
defined relative humidity which can be used for
adjustment.
Transparent wall (plastic)
The containers can be used in any position and with-
out limitation if in perfect condition.
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Description of operation

Defined relative humidities can be created
using saturated salt or acid solutions. With
saturated salt solutions the salt content
remains constant if there is enough undis-
solved salt at the bottom of the container (=
saturated solution). With unsaturated salt
solutions this is not the case (only liquid is
visible) and a defined relative humidity above
such solutions cannot be guaranteed.
NaCl and LiCl solutions are used for control
and adjustment as their relative humidities
are almost temperature-independent (see
graph).

General information

Polystyrene holder
Remove the polystyrene holder from the packaging.
Both containers should remain in the polystyrene
holder during control of the humidity probes since
control and adjustment are temperature-dependent.
Excepted are humidity transducers and data loggers.
Since these instruments are usually used on location
it cannot always be avoided that the respective con-
tainer is removed from the polystyrene holder.
Checking the containers
If there is liquid in the inner part of the container this
must be removed.
The functioning of the containers is guaranteed if
there are enough salt crystals in the 11.3% and
75.3% solutions and the solution is between min. and
max. Therefore the salt solution level should be
checked from time to time. To do this remove the con-
tainer from the polystyrene.
If there are no salt crystals present the containers
should be replaced.
Shake the containers briefly before adjustment.
Screwing off the lid of the container
The containers should only be opened for a short
time. If the ambient air mixes with the air mixture in
the inner part of the container the defined humidity
should be set first when the probe is screwed in or
inserted.
In order to ensure that the containers func-
tion for as long as possible it is important to
close the containers immediately after use.
Clean and dry the sealing surface before
closing.

Handling

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