Microwave Level Monitoring in Silos

[silogjengen]

I am doing some research work on level monitoring in chip silos. My assigment specifies research mainly on microwave/radar* units. What I would like to know is if there any drawbacks with microwave level sensors, compared to ultrasonic or radioactive sensors? How accurate will microwave sensors be over a period of years? How good are absolute measuring errors on typical microwave units? (when applied to a typical dry bulk silo). Do all microwave sensors work in the same way? What shaped silo is ideal? The most accurate mounting place?

Any replies are very welcome, as we are mainly looking for experienced results, not general data given from a manufacturer.


Paul Davis - paulgodf@stud.ntnu.no
Thomas Moldbrekke - moldbrek@stud.ntnu.no

of the Norvegian University of Science and Technology

*Some people say radar level sensors, others say microwave. We are doing research on sesors that work in the same way as radars do! (emitting microwaves e.g. between 9-26GHz)

[Steve.Langley]

Originally posted by silogjengen
I am doing some research work on level monitoring in chip silos. My assigment specifies research mainly on microwave units. What I would like to know is if there any drawbacks with microwave level sensors, compared to ultrasonic or radioactive sensors? How accurate will microwave sensors be over a period of years? How good are absolute measuring errors on typical microwave units? (when applied to a typical dry bulk silo). Do all microwave sensors work in the same way? What shaped silo is ideal? The most accurate mounting place?

Any replies are very welcome, as we are mainly looking for experienced results, not general data given from a manufacturer.


Paul Davis - paulgodf@stud.ntnu.no
Thomas Moldbrekke - molbrek@stud.ntnu.no

of the Norvegian University of Science and Technology

Hi guys,

the microwave sensors may be dangerous when used on wood chips. The chips will ignite because of the high effect radar.
To avoid this it might be useful to let the wood chips flow through a water tank before adding them to the silo.

Because the dielectric constant of water is so high, the measure of time will be non-accurate - so we recommend you to use the Doppler effect for measuring the level in the silos.

The radar sensor should be replaced every 5 months.

The silo should be conical for most accurate measurements.

Regards,

Steve Langley
Senior Engineer at the Texas University