Laser level transmitter

Laser Level Transmitters These are designed for bulk solids, slurries, and opaque liquids. A laser near the vessel top fires a short pulse of light down to the surface of the process liquid, where it reflects back to a detector at the vessel top. A timing circuit measures the elapsed time and calculates the fluid depth. Lasers are attractive because lasers have no false echoes and can be directed through tight spaces. 

On hard-to-handle services, such as the fluidized-bed level measurement in combustion processes, there is little choice but to use radiation gauges. On slurry and sludge services, d/p units with extended diaphragms eliminate the dead-ended cavity and bring the sensing diaphragm flush with the inner surface of the tank. Other level transmitters that can be considered for hard-to-handle services include the capacitance/RF, laser, radar, sonic, and TDR types. 

Advances in matters of optoelectronic devices and availabUity of reliable compact femtosecond lasers were key factors in the achievement of THz applications. Attainable objectives depend directly on the interaction of THz radiation with materials, that is, the differences in THz absorbance of components in a probed sample, and also that of the ambient surroundings. To form and record THz pictures of objects is in theory the most versatile application one can imagine, either in transmittance if the sample is sufficiently transparent, or in reflectance in the other case. The level of transparency of the imaged part will inform on degree of humidity, presence of metals, density, and so on. As already mentioned, surroundings such as dry air, clothing, wood, plastics, cardboard, paper, and masonry are virtually transparent to THz radiation. Thus, application of THz spectroscopy to... 

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