Mollier Diagram


Water is a highly interesting and difficult to handle element. Depending on the ambient conditions of its surroundings its aggregate state can be transformed from liquid to solid or gaseous. The presence or absence of water changes the state of materials – partly intentional, partly unintentionally. The proper- ties of plastics, electronic components, pharmaceuticals, paper, food and many other materials change with an increasing or decreasing water content. Accordingly, the technical detection of moisture in materials, liquids, and solids is demanding. The complex interrelations between relative humidity, air temperature, dewpoint and absolute humidity in g / kg or g/m ³ can be depicted in the Mollier diagram.

In the field of engineering, we implement the solution of customized tasks for process moisture. This includes the adaptation available on the market measuring technology to customer-specific applications, where necessary, the development and production of new sensors or devices. Target of the ambient humidity to infer the product moisture, we determine the necessary sorption isotherms.


Process Moisture can be determined with different methods. Gas humidity for instance is defined in the first instance only as the moisture content in gases, e.g. as in air. However, measured over a moving web, part of the free water which escapes from the material is also recorded (equilibrium moisture content). In a closed system the free water intersperses into the surrounding air (equilibrium moisture content or water activity). Therefore where the humidity is determined directly above a running web or within a closed system, the process moisture can also be recorded provided that the operator has the corresponding sorption isotherm. By determining the relative humidity it is therefore possible to optimise the cost, for example, in drying processes.

The book deals with all aspects of humidity and moisture measurement Moisture Measurement
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