Plastic Optical Fiber Sensor For Continuous Measurement Of Liquid Level

The polymer optical fiber liquid level sensor which has been used have a large range of measurement. It can be used in industry such as flammable and explosive deposited oil place. Considering it is not used as consecutive measurement, this paper design a columned polymer optical fiber liquid level sensor which placed horizontally in the liquid which under detection. This sensor can detect liquid level without any interval and also improve the precision of traditional sensor.This paper focus mainly on two parts.1. Simulate the polymer optical fiber sensor designed in this paper in a theoretical way.(1)Simulate how the power in cladding changes with the diameter of the core.We got how power of cladding changes with the diameter of the core with a series of deduction and program. There are three kinds of fiber using in the experiment. They are refractive index of core 1.59 made of Polystyrene and refractive index of cladding 1.49 made of PolymethylMethacrylate, refractive index of core 1.49 made of PolymethylMethacrylate and refractive index of cladding 1.40 made of interpolymer of tetrafluoroethylene and Vinylidene Fluoride and refractive index of core 1.492 made of PolymethylMethacrylate and refractive index of cladding 1.417 made of polyethylene. From the result we got that it is close among these three kinds of optical fiber with different core diameters.(2)simulate the power of core changes with refractive index of cladding.The power of core changes with refractive index of cladding n2 was simulated in order to know how power of core changes when put the fiber into different liquid. A contrast of power of core changing with refractive index of cladding n2 between fibers with different core diameters. The upper curve describe fiber with lmm core diameter and the lower with 0.9mm.We got that core power of fiber with 0.9mm core diameter is lower than fiber with 1.0 core diameter when they have the same refractive index of cladding n2. The fiber with 0.9mm core diameter has a lower refractive diameter than the fiber with 1.0mm core diameter when have the same core power.2.Prove the usefulness of such liquid level sensor in application.(1) The influence of the number of optical fiber binding to the cylinder.Contrast three sensors with different numbers of optical fiber binding on the cylinder, test each of them with the same experiment. No.1 sensor binds one round of fiber on the sylinder, No.2 binds four and No.3 binds nine. Measure liquid level using these three sensors.We got that the more rounds of fiber binding on the cylinder the more sensitive such sensor will change with liquid level. This is because more rounds of fiber binding on the cylinder means more sensitive points are exist on the sensor. The results shows linear. Handwork could cause some error in the result.(2) The influence of diameter of the cylinder sensorBind same lenghth of fiber on two cylinders with different diameter to made sensor. Each of them are took of the outer side of cladding and test liquid level.From the result we got that the diameter directly influent the volt value. Sensor with smaller diameter causes more sensitive to liquid level. This is because smaller diameter means more power will lose from the sensitive position which lead to more sensitive to the change of liquid level.(3) The influence of the level we take of the cladding.Contrasting three sensor with different level which we take of the cladding.No.1 sensor is took of 0.1mm deep, No.2 sensor is 0.2 and No.3 is 0.3mm.We could got that No.1 sensor is less sensitive to the change of liquid level. On contrary No.3 sensor is the most sensitive one. This is because with the level goes more deeper than 0.125mm which is the thickness of cladding, some of the core is also take off. No.2 and No.3 sensor both are take off with some core which make the power lose more than the situation which only cladding is take off. More power lose means more sensitivity.