We are looking for a non-contacting level measurement device that will work on finished cement storage silos, on homogenizing silos and on clinker storage bins. The largest silos are 38m high and 10m in diameter. It is required that the level is measured continuously and in all conditions, also during filling when a lot of dust is formed. In total we need 21 units and all will be connected to a PLC via 4 to 20 mA or fieldbus.

I believe Endress & Hauser with their ultrasonic and time domain reflectometer technologies would be the people to help you out.

We determinate free lime by X-ray, but when we make a program to determinate it. This program has a life period about one month, after that, the program starts to give wrong results and we can?t calibrate it, because the problem becomes bigger. What can we do to eliminate this problem and what can we to do to improve the program.

I presume you are using X-ray diffraction to determine the free lime but the problem is that the calibration drifts with time. I suggest that you measure the free lime by traditional titration once per day. The program can then be modified to continuously update the relationship between the free lime and the XRD intensity using the last 20 results. In this way the calibration will be continuously updated and there will be no need to make a special recalcibration once per month.