VIDEO: htttp://www.youtube.com/v/z-7KWeCHIlU

Configured was a non-contact radar measurement device from UWT combined with a visualization software.

Non-contact continuous level measurement

UWT (UK) Limited proposed the use of the free-radiating radar NivoRadar® NR 3100 which could be supplied with an aiming flange. The integrated aiming flange allowed the radar to be mounted in the same position as the previous acoustic wave device which was close to the silo side wall and which allowed for the narrow 4˚ beam to be aimed towards the lowest point of the silo. This saved the customer time and money as they didn’t need to move the mounting position towards the centre of the silo where the silo was filled from.

Free-radiating radar sensors can determine the level of a medium without contact. The so-called FMCW radar measurement method (Frequency Modulated Continous Wave) is used for this purpose. The transmitted signal is modulated between two known frequency values (NivoRadar® 78...79 GHz) and the difference between the transmitted signal and the echo signal is measured. This difference frequency is directly proportional to the transit time and thus to the distance. The level can then be calculated by adjusting the respective vessel height.

Bring the levels to where the planner needs them

The visualizing system that the customer had been using previously was very basic and limited and did not allow them to display the contents in any other way than the level of the material. The customer required the contents of the silo to be displayed in tonnes or percentage of fill.

Various technologies are available for level indication. Simple LED digital displays for the evaluation of a 4-20 mA signal for installation in control cabinets or up to wall mounted touch panels and web server modules with visualization software. These can then be configured on a project by project basis and adapted to customer requirements.

The NivoTec® NT 4600 with cabinet mounted digital display fulfilled the need by allowing the customer to choose which information they would like to see including level, tonnes, percentage, volume and a number of other options via a 7” touch panel. It is inexpensive due to a standardized software and makes an evaluation of up to 15 level sensors and 15 max detectors possible. It can be used as a built-in module in an existing control cabinet or supplied as a complete module in a pre-wired control cabinet.

The customer was more than satisfied with the sensor solution:
”Thank you Graeme Hughes and UWT (UK) Ltd. This upgrade to our level monitoring system has both improved worker safety and improved accuracy for our clean wheat plant bulk tank levels.”