Study and design of a liquid level meter based on fiber-optic sensing technology

摘要

At present, many floater-type measurement equipments whose readings are recorded by manpower are still in use in petrol-chemical industries. With regard to their low efficiency , great errors and their improbability in realization in automation management and remote control, in this instance, a new liquid-level meter system using the advanced fiberoptic sensing technology based on the floater-type level meter is developed. In principle, it measures the liquid level of the oil tank by using the principle of force balance, captures and transmits the light signals by means of the fiber-optic sensing technology, adjusts the light signals from continuous impulse signals to the discontinuous by the light-code disc, then converts light impulses into voltage impulses by photoelectric elements. In configuration, it adopts a twin light source and a twin optical-channel, utilizes twin fiber detectors to record the size of the liquid level and judge the direction of the liquid level respectively. Moreover, the measuring system has been tested practically in a chemical plant, the results indicate that the measuring errors are ≤ ± 6mm, relative errors are < 2% when its measuring range is within 0 and 1000mm. It is proved that the various indexes of the system satisfies the demand of the industries and the capability is credible.