For ultrasonic measurement a sensor would need to be held near the top of the silo, above the highest level of cement measuring the distance to the top of the cement. From this measurement the level and/or volume of cement can easily be calculated.
Sensor location could be acheived by removing a small section at the top of the silo and mounting a sensor which could be wired into your silo control system for automation purposes.
A sensor of this sort would cost approx USD500, the sensor would be configured to meet your specific requirements (measuring range, accuracy etc).
It would be possible to install such a system using in-line connectors etc. so that it could be quickly easily moved from one silo to another.
What your post seems to be requesting, -a sensor to scan through the wall of the silo and detect the material behind is possible but the scanning sensors (& software) of this type are much more expensive (circa USD 10,000) and tend to be used for ground scanning applications i.e. archeologists looking for buried buildings or service engineers looking for buried pipes.
Another approach would be to insert pressure sensors at the bottom of each silo prior to filling, obviously this would not be a portable solution but possibly the cheapest and simplest option especially in a pressurized silo.
Skyview Systems are based in the UK specializes in sensor technology and can find a solution to meet your requirements and budget.
Well, that can be anything from a sight glass to a tuning fork to a nucleonic detector; it needs much more of a specification in order to select one.
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