Equilibrium moisture: Difference between revisions

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{{EngVersion|text=[[Hschwarz|Hans-Jürgen Schwarz]]}}
Author: [[user:Hschwarz|Hans-Jürgen Schwarz]]
Author: [[user:Hschwarz|Hans-Jürgen Schwarz]]
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English Translation by [[user:SLeithaeuser|Sandra Leithäuser]]<br>


back to [[moisture|Moisture]]
back to [[Physical Principles of Moisture|Physical Principles of Moisture]]
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== Abstract ==
 
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''The equilibrium moisture content of a material is a function of the moisture content of the ambient air and temperature. It is defined by the maximum moisture a material can hold at a certain relative humidity and temperature in equilibrium with its environment''
Ähnlich wie die Gleichgewichtsfeuchte eines Salzes kann auch die Gleichgewichtsfeuchte einer Materialprobe wie folgt definiert werden:  
 
Similar to the equilibrium moisture content of a salt, the equilibrium moisture content of a sample may be defined as follows:


{| cellspacing="0" cellpadding="10" style="border: 1px solid black;"
{| cellspacing="0" cellpadding="10" style="border: 1px solid black;"
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| bgcolor="#ffff99" | ''' Die Gleichgewichtsfeuchte ist die massebezogene Materialfeuchte eines Materials, bezogen auf konstante Randbedingungen, die sich mit der Zeit einstellt. '''<br>
| bgcolor="#ffff99" | ''' The equilibrium moisture content is the mass-related moisture content of a material at constant boundary conditions. '''<br>
|}
|}


The sample does not become wetter or dryer. It is thus clear, that the  determination of equilibrium moisture content can be more important than the determination of the actual moisture content. In many materials the change in moisture causes expansion or contraction, which then causes damage. If the moisture of the ambient air differs from the equilibrium moisture it re-occurs through moisture uptake or release. The equilibrium moisture content of a sample decreases with temperature increase.


Die Probe wird dann also weder feuchter noch trockener. Es ist somit klar, dass die Ermittlung der Gleichgewichtsfeuchte wichtiger als die Ermittlung des tatsächlichen Wassergehaltes sein kann. Bei vielen Materialien bewirkt eine Feuchteänderung ein Dehnen oder Schwinden und führt so zu Schäden. Weicht die Feuchte der Umgebungsluft von der Gleichgewichtsfeuchte ab so stellt sich durch Feuchteaufnahme bzw. Feuchteabgabe die neue Gleichgewichtsfeuchte wieder ein.
[[category:Moisture Measurement]][[category:Schwarz,Hans-Jürgen]][[category:inProgress]]
Die Gleichgewichtsfeuchte einer Probe nimmt mit zunehmender Temperatur ab.
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[[category:moisture]][[category:HSchwarz]][[category:inProgress]]

Latest revision as of 18:52, 23 January 2013

Author: Hans-Jürgen Schwarz
English Translation by Sandra Leithäuser

back to Physical Principles of Moisture


The equilibrium moisture content of a material is a function of the moisture content of the ambient air and temperature. It is defined by the maximum moisture a material can hold at a certain relative humidity and temperature in equilibrium with its environment

Similar to the equilibrium moisture content of a salt, the equilibrium moisture content of a sample may be defined as follows:

The equilibrium moisture content is the mass-related moisture content of a material at constant boundary conditions.

The sample does not become wetter or dryer. It is thus clear, that the determination of equilibrium moisture content can be more important than the determination of the actual moisture content. In many materials the change in moisture causes expansion or contraction, which then causes damage. If the moisture of the ambient air differs from the equilibrium moisture it re-occurs through moisture uptake or release. The equilibrium moisture content of a sample decreases with temperature increase.