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Laboratory Electronics

MATERIAL HYGROMETER LB-796


  • 2 measurement methods
  • measurement characteristics for many materials
  • interface RS-232 for calibration

LB-796

DESCRIPTION

Material hygrometer LB-796 is designed for absolute humidity measurement of wood, walls and other materials for which it was calibrated.

There are two measurement methods available in the hygrometer.
  • resistance method,
  • capacity method.
There are two versions of the measurement electrodes for the capacity method: 
  • flat electrodes - LB-796A,
  • needle electrodes of length:
    • 2cm    LB-796C,
    • 15cm - LB-796E.

The electrodes are attached permanently to the meter. The needle electrodes are assigned for soft materials i.e. foamed polyester, clay, cereals. They can have various lengths depending on the type of material and user requirements. The flat electrodes are assigned for hard materials i.e. wood, brick, concrete etc.

In case of the resistance method of humidity measurement it is performed using a resistance probe ended with the gripping devices. It is possible to disconnect the probe from the hygrometer. 

The main features of the hygrometer LB-796 are: 
  • big, easy to read LCD display, modern casing, applied energy saving measurement microprocessor,
  • material humidity measurement using a resistance and capacity method,
  • possibility of meter’s calibration for a specific type of material by a user or in a laboratory – calibration parameters are stored in a non-voltage memory of the meter (it is possible to store 20 types of materials), a user can receive a meter’s calibration certificate for a certain type of material,
  • temperature measurement using a sensor built-in the meter in the scope 0...50 °C  or an outside sensor in the scope –10...70 °C,
  • automatic compensation of temperature influence on wood humidity for a resistance method,
  • battery powered,
  • automatic hygrometer switch off after 2 minutes of inactivity,
  • signaling of the exceed of the measurement scope,
  • signaling of the electrodes short-circuit of the capacity probe,
  • two threshold signaling of low battery voltage,
  • digital neutralization of the capacity probe.

TECHNICAL DATA  

The hygrometer is calibrated in such way, so it indicates a mass humidity, which is defined as a ratio of water content in a material to a mass of absolutely dry material (in %). There is also a possibility of scaling the meter, in such way, so it indicates otherwise defined humidity or a material electric permittivity.

The measurement scope and measurement uncertainty for the materials available in the meter are provided in an annex to an instruction manual of a certain meter.  The measurement resolution amount to 0,1 %.

The measurement inaccuracy of wood humidity depends on many factors such as i.e. wood flaws in a spot of taking a measurement, uneven distribution of humidity in wood, improper way of taking a measurement. The influence of those factors (each treated separately) is not big and should not provide any meaningful reflection on a measurement result. However, when few on them appear simultaneously and in their unfavorable accumulation they can lead to serious measurement errors. When taking a measurement one should follow all comments and indications described in the appropriate chapters of the device user manual.

Wood humidity can be divided to two characteristic scopes:
  • hygroscopic scope of humidity 0...30%: it is a scope of humidity that wood can accept in the air of humidity 0 –100% (wood that stays in the air of  certain humidity absorbs water from air and accepts so called equivalent humidity),
  • scope of humidity above 30%  i.e. “live” wood or wood that stayed in the water.

The upper scope of hygroscopic humidity 30% is conventional and for various types of wood assumes value 23% do 33%.

Meteorological parameters for temperature
  Outside sensor
Inside sensor
scope -10...70 °C -0...50 °C
resolution
0,1°C 0,1°C
measurement inaccuracy
 +/- 0,5 °C +/- 0,5 °C
POWER SUPPLY
battery
1 battery 9V type 6F22
energy consumption
4 mA - temperature measurement
6 mA -  resistance method
38 mA - capacity method
SCOPE OF WORK TEMPERATURES
Device Scope Comments
Meter LB-796 0..+50 °C Water outdropping is unacceptable
See also
See also
Wilgotnościomierz LB-795 Wilgotnościomierz LB-795
A material hygrometer LB-795 is designed for wood relative humidity measurement.
LB-797 LB-797
Wilgotnościomierz do gleby oraz innych materiałów sypkich to precyzyjny miernik wilgotności. Producent wilgotnościomierzy ze świadectwem wzorcowania.
LB-798 LB-798
wilgotnościomierz, higrometr do pomiaru wilgotności materiałów sypkich, wilgotnościomierz do piasku,
Ocena produktu
Ocena: 5/5, liczba głosów: 14
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