Humidity Reference Cells; Functional Principle Humidity Reference Cells; Performance Features; Fields Of Application - Beko DP 207 Manual De Instalación

Humidity reference cells

10 Humidity reference cells

10.1 Functional principle humidity reference cells

The humidity reference cells serve as humidity measurement standards in order to provide stable humidity
values for test purposes or for calibration of measuring instruments. The achievable accuracy is within the
range of 1 % relative humidity.
The functional principle is based on a saturated salt solution which leads to a particular relative air humidity.
The reference cells in addition contain a semi-permeable teflon membrane (diaphragm) which separates the
salt solution from the measuring area. The membrane is permeable for vaporous water molecules, but not
for the salt solution or for liquid water. The humidity value in the measuring area corresponds to the relative
air humidity above the salt solution. The membrane makes handling the cells much easier: The reference
cells can be inserted upside down. There is no risk of the salt solution leaking out and thus spoiling the test
item. Furthermore, the salt solution is protected against contamination coming from the outside. The active
membrane area is rather large compared to the inside volume which leads - after insertion of the test item -
to quickly stabilizing humidity values.
The cells are mechanically stable and transparent. Thus, the humidity level and the air saturation can be
monitored from the outside. The sensitive membrane is protected by a plastic insert. The humidity curve in
dependence on the temperature can be seen on the label of the containers. The temperature range is from
32°F to 122°F.

10.2 Performance features

• Reference cells for relative air humidity
• 7 versions with different salt fillings from 11% RH up to 97 % RH available
• High accuracy due to chemically pure salts
• Integrated teflon membrane as separating barrier between salt solution and measuring chamber
• Optimized housing with favourable ration of membrane surface to inner volume
• Transparent design for visual controllability of saturation and liquid level
• Temperature range from 32 to 122° F
• Made in Germany

10.3 Fields of application

Due to the high accuracy the reference cells are suitable for calibration of capacitive humidity measuring
instruments.

10.4 Durability

When applied correctly, the cells can be used for many years. If the liquid level changes just send in the cells
to our customer service department for regeneration or for refill.

10.5 Versions

The version offered is equipped with a ½" inner thread that allows the compressed air probe or the instru-
ment DP 207 to be directly screwed in leak-proof. The reference cell is available with seven different salt
solutions. The salts used are of the highest laboratory quality.
For further information please contact us.
12 DP 207