In this work, a simple but versatile sensing system for very accurate sensing of liquid level and liquid density is presented. The sensor works based on basic strain sensitivity of Fiber Bragg Grating (FBG) and principle of liquid obeying Archimedes’ law of buoyancy. In this system,
a cylindrical shaped mass suspended from a Fiber Bragg Grating and partially immersed in the liquid to be sensed. If the liquid level in the container or liquid density varies, that change the up thrust on the suspended mass and load on the Fiber will be changed accordingly. The change in
the load on Fiber changes strain on the FBG and the reflected Bragg wavelength also changes. The proposed device with proper calibration should be able to carry out real time and nonstop liquid level and liquid density measurements. A mathematical analysis of the system considering liquid
properties and geometrical structure of the suspended mass is presented here. Sensitivity of the system for liquid level monitoring is also reported. Achieved results shows the path for the utilization of the proposed sensor system for precise liquid density measurement and liquid level sensing
in very large storage tanks used for commercial/residential applications.
The first trial of equipment designed for 400 Mc./s. absolute flux density measurement was completed just prior to this symposium. Using the midday sun, the gain of a 7·5 metre Würzburg (equipped with a TE°11 circular wave-guide feed) was found by comparison with an ‘optimum’ pyramidal horn of 20·2 square wave-lengths aperture. Cable losses and signal powers were measured against the available noise power from two co-axial resistors, one at ambient temperature and the other stabilized at the boiling-point of pure nitrogen.
The large power current is sampled by Rogowski coil, then transforms the sampling signals from AC to DC and regulates the signals, the current detection unit is formed with FBG (Fiber Bragg Grating) and GMM (Giant Magnetostrictive Material), the current measurement is achieved based on the F-P interferometer filter demodulation system, finally, linear relationship between the Bragg wavelength shift and external current is validated by experiment.
Flux density measurement for industrial-scale solar power towers using the reflection off the absorber
