Optical fiber continuous liquid level sensor on basis of end face reflection coupling

Abstract

The invention discloses an optical fiber continuous liquid level sensor on the basis of end face reflection coupling. The sensor is an all-optical fiber sensor, which can be used for continuous measurement of the liquid level in a severe environment; a sensor probe part comprises a sending optical fiber bundle and a receiving optical fiber bundle, the two optical fiber bundles are wrapped in a shell, optical fibers are adhered through an adhesive, detection end faces of the optical fiber bundles are in a wedge shape, through the design of the wedge-shaped end faces, side coupling of the sending optical fiber bundle and the receiving optical fiber bundle can be achieved, the sensitivity of the sensor is improved, and droplet adhesion is lowered; by controlling the diagonal angles of the wedge-shaped end faces and the incident beam angles of the optical fibers, total internal reflection is conducted on emergent beams in the end faces of the optical fibers in the air, Fresnel reflection is conducted on emergent beams in the end faces of the optical fibers in a liquid, and when the liquid level is different, the total power of reflected beams is different, so that liquid level measurement is achieved. The sensor has the advantages of integrated structure and design without movable parts, high sensitivity, high safety and high reliability.

Description

technical field [0001] The invention belongs to the technical field of photoelectric sensors, and more specifically relates to an optical fiber continuous liquid level sensor based on end face reflection coupling, which is used for measuring liquid height. Background technique [0002] The current continuous liquid level sensor is mainly capacitive liquid level sensor. This type of sensor has a simple structure and fast response speed, but it is easily affected by factors such as temperature and environment, and needs to be calibrated regularly. If there is water in the fuel, it will cause false finger or even short circuit of the sensor. The ultrasonic liquid level sensor has a simple principle and a small structure, but the speed of sound waves is easily affected by temperature, and the shaking of the liquid surface will affect the reflection of ultrasonic waves. The hysteresis stretching liquid level sensor has high reliability and good safety performance, but it has mov...

AI Technical Summary

Problems solved by technology

The pressure type liquid level sensor measures the liquid level through the static pressure of the liquid, which is easily affected by the geographical location and additional acceleration, and the measurement accuracy and application occasions are limited.

Leakage optical fiber liquid level sensor uses the transmission loss of optical fiber to measure liquid level. Plastic optical fiber is usually used. Plastic optical fiber is greatly affected by temperature. At the same time, due to the small amount of leakage light intensity modulation, it is easily affected by light source fluctuations.

[0004] CN201610303327.5 discloses a fiber optic continuous liquid level sensor based on the principle of scattering. The angle setting of its wedge-shaped end face lacks theoretical basis and needs to be determined by experiments, and it has been proved by experiments that the scattered light intensity is very weak, and it is difficult to detect the light intensity by the receiving optical fiber. , the feasibility of which is questionable

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