Sensors keep track of moisture content

Edited by the Engineeringtalk editorial team Feb 7, 2003

Aquatrim RF-powered online systems measure the moisture of powders in absolute or relative terms, by using the different dielectric properties of each product or material.

Aquatrim RF-powered online systems measure the moisture of powders, sugar, grains, polymer pellets, foundry sand, coal etc, in absolute (parts per million) or relative (percentage) terms, by using the different dielectric properties of each product or material.

Moisture content in oils can also be measured.

Units will operate at temperatures up to 200C.

There are three sensors designs to allow for measurement of moisture in a variety of applications.

The basic sensor can be used on conveyor belts - handling powder, sand, sugar etc.

There is a Pyrex glass measuring sensor for free-flowing materials in pipes, such as powders, pellets, grains etc.

And a Pyrex glass pipe fitting can be used to measure moisture in liquids, oils etc.

The dielectric constant of materials is influenced by its chemical composition and therefore by its water content (moisture).

Energy waste, material degradation, packaging, storing and production problems may occur after incorrect drying processes (too short or too long periods in dryer, high temperatures, insufficient air flow, dew point too low).

An incorrect drying process, may cause flow, filling/packaging and storage problems with bulk materials.

In the case of polymers, hydrolysis in the pellets with consequent lowering of the melt index may occur.

In this last example, the problem may not be detected until scrap production appears and then the extruders must be cleaned originating a very serious loss.