On the other hand, industry frequently needs to measure fuel levels in tanks such as public-transport systems or service stations and click here any other large containers which implies exposure to harsh or highly flammable environments, as in the case of petroleum derivatives. Different methods such as mechanical, capacitive, inductive, ultrasonic [2], acoustic [3] or optical can be implemented. Typically, mechanical and ultrasonic methods are used to detect the level of solid materials that are in the form of dusts whereas capacitive and optical methods give better results in detecting fluid levels. Traditionally, in the case of gasoline stations, a common measurement method is to plunge a measuring rod into the underground tank to determine the fuel level. This rudimentary method tends to be slow and inefficient.
In the automotive industry the fuel level is measured by a float connected to a variable resistance indicating the level of the liquid inside the tank. The main disadvantage of this system is that an electrical current must be introduced into the flammable (or simply conducting) liquid. In particular, if a flammable environment is a critical concern for industrial sensor applications, the optical solution is one of the best candidates to provide an intrinsically safe fuel level measurement scenario thanks to the passive nature of the light and dielectric properties of the fiber.Fiber-optic sensor solutions have attractive properties for liquid-level measurements in practice. Moreover, submersion or flooding can be monitored by detecting radiation losses in bends and reflective intensity variations because of surrounding material changes.
These applications can be carried out in oil tanks, containers, bio-mass boilers in condominiums, flood areas and underground [4,5], or even in lead-acid batteries [6]. At the same time, it should be outlined that in the optical sensing Dacomitinib field, fiber-optic sensors can be constructed using polymer optical fibers (POFs) or silica-based versions, both singlemode (SMF) and multimode (MMF), but POFs have large numerical apertures, simple alignment to optical devices, high coupling efficiency, more flexibility, and lower cost. These are some reasons why new POF-based sensors have appeared and are still appearing, most of them based on optical power intensity detection. However, for remote monitoring ZD1839 over long distances, POFs have inherent disadvantages such as high attenuation losses and incompatibility with commercialized silica-based optical fibers.In fact, optical fiber sensors for liquid level measurement have been extensively studied. Most liquid-level optical sensors are discrete or point-level sensors.