Using the microwave system from Berthold, the water content or dry content of fluids and solid matters can be measured online.

Depending on the application, various microwave sensors can be applied:

For example

• Insertion sensors for the measurement in process containers or crystallizers
• Pipeline sensors for the inline measurement in pipe.
• Horn antenna for the measurement on a conveyor belt or in a chute. 

The suitable measuring arrangement can be configured by the wide spectrum of sensors.

Measuring Principle
The microwave irradiates the product with very little power (< 0.1 mW). The material components are polarised at different strengths and as a result of this, the microwaves lose on speed and energy. Thereby, the speed reduction brings about a phase shift and the weakening of the energy effects an attenuation of the microwave. 

If there are free charged particles in the product or polar materials like water molecules H2O, then this effect is disproportionately intensified. The water influence is 40-times larger as the influence of other components. Hence, it is clear how selectively sensible the water components can be measured.

Figure 1 to 3 only shows a section of a possible arrangement. Basically a measuring system always consists of:

1. An evaluation unit including a microwave module
2. A set of high frequency cables and
3. A microwave sensor or two antennae.

Radiometric area weight compensation can complement the measurement on bulk goods as an option, see arrangement 3. When strong fluctuations occur, the measuring accuracy can be increased considerably.

Advantages:

• High accuracy by selective sensitivity to water.
• Representative measurement by recording of the complete material interface.
• Simple installation by computerised sample taking and automatic calibration.
• Robust sensors, use of wear resistant materials.
• Contactless, dependeing on sesor.
• Very low amount of maintenance.

Examples of successful applications

Sugar industry  

• Brix Measurement

Food Industry

• Butter
• Caramel
• Cream cheese
• Curd

Power Station Industry

• Gypsum suspension
• Milk of lime

Chemical Industry

• Acids
• Resin in Water
• Silicic Acid
• Synthetic solutions

Others

• Coking Coal
• Hard and Brown Coal
• Sand
• Wood Chips

[1]   Evaluation unit incl. microwave module
[2]   High frequency cable
[3]   Microwave sensor: insertion probe,
       pipeline measuring cell or horn antenna.

[4]  Scintillation detector
[5]  Gamma source

		Prospect Micro-Polar LB 566 (pdf, 767 KB)

		Prospect Micro-Polar Brix LB 565 (English language, pdf, 544 KB)

		Prospect contactless measurement of water content and moisture Micro-Moist LB 456 (pdf, 667 KB)

		Microwave measuring technology for sludge draining (pdf, 214 KB)

		Microwave measuring technology for the sugar industry (pdf, 1,53 MB)

		Flyer Mining Applications (pdf, 369 KB)