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Product news
27.03.2024  |  1518x
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New ways of measuring moisture in the process with Ludwig

The determination of product moisture in various processes has always played an important role, be it the moisture measurement of individual raw materials or the entire batch.
In the manufacture of products, the exact moisture content is a decisive feature for dimensional accuracy, appearance, feel and durability in order to guarantee the desired quality of the product.

Economical and resource-saving

In today’s world, which is accompanied by rising energy costs, moisture measurement that is well integrated into the process helps to reduce production costs.
Resource-saving handling of bulk materials is fundamental and must be aimed for. In addition, CO2 emissions can be reduced to the necessary minimum in possible drying processes.

Optimal measurement under difficult conditions

The dielectric microwave measuring head requires direct contact with the measured medium. The high-frequency measuring signals penetrate at least 50 mm into the material to be measured, so that even deeper medium moisture levels are accurately detected and a larger quantity of bulk material is measured. The HF power of the probe absorbed by the measured medium is used for the moisture display via a calibration curve.

Moisture measurement anywhere in your process

Examples include high-performance, drying and mixing machines in which strong turbulence occurs during the mixing process, as well as dosing belts, conveyor lines and silo closures with a wide variety of nominal widths and discharge quantities. Individual problems can influence the exact function of moisture measurement sensors in all the application processes mentioned.

Use of several sensors

Different dosing capacities and speeds, a small coverage of the sensor measuring field and an uneven moisture distribution in the measured medium can pose challenges when using several sensors. During development, it was necessary to arrange several sensors in a very small space without causing interference in the high-frequency measurement signal. The advantage of a compact yet robust sensor design was retained, which makes it easier to install the sensor at suitable process points. Up to four sensors can be connected together.
  • The arrangement of the individual sensors on a baffle plate, see image 1, is intended for the dosing of very small quantities or intermittent discharge of bulk materials at containers or the transfer points at various dosing devices, such as chain and screw conveyors or vibrating chutes.
  • In image 2 a rod with three sensors is shown. In this way the measuring units can be easily inserted at different levels of a bulk material flow, or across the entire width of goods produced on rolls, such as textiles, fabrics, etc. using one mounting point.
  • See image 3 for moisture measurement with FL-WAPP sensors in the production of insulating wool.

Tailor-made for your process conditions

The sensor models described are also available for a wide range of requirements. These include a declaration of no objection for food, animal feed, chemical and pharmaceutical production plants, for use at high temperatures up to max. 130 degrees Celsius and a version for dust protection zone 20.
Thanks to extensive interfaces, the humidity measurement sensor can be easily integrated into existing process control systems. It can be connected to the process control system via analog outputs with 0-20/4-20 mA, as WLAN UDP or TCP/IP protocol and a TTL interface.

Individual measurement signals

For example, an average value of the moisture content of the measured medium can be output from all the moisture measurement signals received from the sensors. One might think that incorrect measurements are inevitable if one or more moisture measurement sensors have not detected enough material. This and other effects are avoided by intelligent filtering of the measured values of all sensors, so that a high and stable measuring accuracy of the sensor unit is guaranteed even under difficult conditions.

Franz Ludwig GmbH can look back on half a century of practical experience in the use of its own moisture measurement sensors for a wide range of process requirements. This is our incentive to continue to develop individual solutions for processes in the future and to implement them successfully in practice.

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