An optical fiber point liquid level sensor based on end surface reflection coupling

Abstract

The invention discloses an optical fiber point-mode liquid level sensor based on end face reflection coupling, and belongs to a photoelectric sensor, and the optical fiber point-mode liquid level sensor is mainly used monitor high-low liquid level and measure disperse liquid level. The sensor comprises an emission optical fiber bundle and a reception optical fiber bundle. The optical fiber bundlesare wrapped in a housing. The optical fiber bundles are bonded through an adhesive. One end of the emission optical fiber bundle and one end of the reception optical fiber bundle are used as sensor probes, and are slantly cut into wedge-shaped end faces. The other end of the emission optical fiber bundle is used as a light source incidence end, and the other end of the reception optical fiber bundle is used as a reflection light detection end. Through side surface coupling of the reception optical fiber bundle and the emission optical fiber bundle, and size of reflected light power can be detected, so as to know what kind of medium each wedge-shaped end face of the probe is in. The sensor is simple in structure and easy in implementation, and can be used in severe environment of high temperature and high pressure, and flammable and combustible environments, and is advantaged by high sensitivity and high precision.

Description

technical field [0001] The invention belongs to the technical field of photoelectric sensors, and more specifically relates to an optical fiber point liquid level sensor based on end surface reflection coupling, which is mainly used for monitoring high and low liquid levels and measuring discrete liquid levels. Background technique [0002] At present, fiber optic sensors have attracted widespread attention in the industry due to their excellent security and anti-interference capabilities, and have been used in many fields. In terms of discrete point liquid level measurement, there are mainly the following types of fiber optic sensors. The prism-type optical fiber liquid level sensor uses the principle of frustrated total internal reflection to measure the liquid level. When the probe is in different media, due to the different refractive index, the light amount of total internal reflection is different. By measuring the reflected light power, it can be known whether the pri...

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Problems solved by technology

The prism-type optical fiber liquid level sensor uses the principle of frustrated total internal reflection to measure the liquid level. When the probe is in different media, due to the different refractive index, the light amount of total internal reflection is different. By measuring the reflected light power, it can be known whether the prism is consistent with the liquid surface. Contact, this kind of sensor needs to bond the optical fiber and the prism together, the process requirements are high, and there is a risk of fracture in the vibration environment; the tip reflective optical fiber liquid level sensor is also based on the principle of frustrated total internal reflection, but it directly connects a single or The two optical fiber heads are processed into a cone instead of a prism to become a probe. The sensor is difficult to process and it is difficult to ensure repeatability; the leaky optical fiber liquid level sensor uses the different light power leaked in different media to detect the liquid level, but due to the leaky optical fiber Most of them are plastic optical fibers, so the temperature adaptability of the sensor is poor

[0003] CN201510413938.0 discloses a fiber optic point 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. There are doubts about the feasibility of its principle; and when the sensor detects multi-point liquid levels, Multiple fiber bundles are required, and the overall structure is relatively cumbersome and complicated

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