Polymer Optical Fiber Intensity-Based Sensor for Liquid-Level Measurements in Volumetric Flasks for Industrial Application

Abstract

A low-cost intensity-based polymer optical fiber (POF) sensor for liquid detection applied to volumetric flasks is presented. Experimental results demonstrate the viability of the POF-based sensor system in a high-accuracy liquid level measurement scenario. Moreover, a wireless mesh sensor network based on ZigBee specification protocol to address multiplexed POF-based sensor is also developed. Experimental results demonstrate the feasibility to address a high number of optical sensors in an industrial process framework by means of this low-cost wireless solution.

Liquid level gauge based in plastic optical fiber

“…Thus, any external disturbance to the surrounding environment produces a measurable effect on the signal optical power at the fiber output. Comparing the proposed solution with other previously reported, such as in references [17][18][19][20], although the detection scheme could be similar, the sensor here proposed is simpler and cheaper to manufacture and its assembly in the measuring field easier, because it uses one stretched fiber, without bending or sensing heads. Bended and polished fibers, such in [17] are also more susceptible to failure due to internal stresses in the curvature, furthermore each bending increases a fixed term of attenuation that might considerably decrease the measuring range.…”

“…Montero and Vázquez demonstrated an intensity based POF sensor for liquid detection in volumetric flasks, normally used in chemistry [19]. In the developed platform, light was launched from a fiber illuminating the volumetric flask and received into a fiber placed at the same longitudinal axes.…”

“…Bended and polished fibers, such in [17] are also more susceptible to failure due to internal stresses in the curvature, furthermore each bending increases a fixed term of attenuation that might considerably decrease the measuring range. A sensing head, such in [18,19], may add alignment complexity to the sensor manufacturing and stability during operation. The sensor referenced in [20] cannot make level measurements with one fiber, and also requires a more complex manufacturing process.…”

Assessment of Scattered-Bend Loss in Polymer Optical Fiber (POF) Displacement Sensor

“…Among the techniques proposed by researchers are longperiod gratings [19], nonlinear effects [20], surface plasmon resonance [21] and fiber bragg gratings [22]. An intensity-based technique has addressed a high-performance, simple, and a lowcost sensor for various detections based on the approaches indicated above since it does not require specific equipment [23]. A sensor that uses light intensity as the measurement detecting technique is known as an intensity-based sensor [24].…”

Increasing the Sensitivity of Polymer Optical Fiber Sensing Element in Detecting Humidity: Combination of Macro and Micro Bendings

“…There are various methods in constructing humidity measurement devices, i.e., humidity sensors based on 1) optical absorption, 2) gratings, which consists of fiber Bragg and long period fiber gratings, 3) interferometry, e.g., Fabry-Perot, Sagnac, and modal interferometers, 4) resonators, e.g., microloop, microring, microtoroid, and microsphere, and 5) electromagnetic resonances, especially lossy mode resonances [1,2]. The aforementioned sensing methods have their own advantages, and therefore utilized according to the intended applications, e.g., humidity measuring devices based on induced-stress-optic effect [4], agarose gel [5,6], evanescent wave scattering [7], liquid-level measurement for industrial application [8,9], and displacement sensors [10].…”