Overview Moisture Measurements
Just a few physical properties pass so manyfold through our daily life as moisture. The value of moisture is in many areas one of the important features of a product. Moisture has high meaning for the quality of products, for their processability or for the energy consumption during handling. This parameter often is neglected, although quick and informative moisture measurement can help to save high amounts of costs.
In commercial organic processes moisture content is besides the temperature the most important property. Decrease of moisture content below an optimal moisture content for the desired application leads to death of microorganisms carrying the process, while exceeding the optimum range leads to fouling.
In other applications moisture is a expression of quality, for instants when products are delivered or have to processed. Some billing systems - like in plastics recycling or in the use of biomass and woodchips- are based on moisture known or to be measured, or they are planned to base on moisture data. For deciding what is good or not it is necessary to not only have surface moisture, but also moisture infomation about the kernel of the material.
For singular reference measurements it is often sufficient to carry out spot checks and to determine the water content by drying methods or chemical reactions. Such spot checks are always combined with high personal effort and with a time delay of hours or even days.
Fast process solutions for field use or moisture measurements on a statistical basis taken from many singular measurements only can be realized with non-destructively operating moisture measurement methods.
Microwave moisture measurement methods are of this. Since more than 40 years they have been known. Starting form the 80s one can consider microwave moisture meters to be established in the process environment. Since more than 5 years they have been available as portable moisture meters too.
Microwave moisture measurements have some principal advantages over other methods due to physical reasons. They are:
The until now most essential disadavantage of microwave moisture meters - their high price - was the main reason for only using them in applications, where no other solution was found.
This has changed very rapidly with the realization of the MOIST system. MOIST is a cost-effective unit construction system consisting of a number of moisture sensors with different microwave principles. To the system also control units and software tools are belonging. There are no applications where the use of a MOIST moisture sensors cannot be imagined.