Externally pasted fiber grating sensor for diaphragm filter plate, and detection system and method

Abstract

The invention discloses an externally pasted fiber grating sensor for a diaphragm filter plate, and a detection system and method. The sensor comprises a plurality of fiber grating packaging pasters that are pasted to a diaphragm filter plate of a filter press and are arranged in a matrix mode. The fiber grating packaging pasters having the same structures consist of substrates, fiber gratings arranged on the substrates, and conduction fibers connected with the fiber gratings; the fiber gratings and the substrates are packaged in an integrated mode to detect the diaphragm filter plate strain and / or a temperature change. According to the invention, the fiber grating sensor uses the substrate made of a glass-fiber-reinforced epoxy resin composite material, so that the slight strain at the frame of the diaphragm filter plate can be monitored precisely. Besides, a sensor-based intelligent health monitoring system of the diaphragm filter plate is also provided; and real-time, reliable, and overall health state monitoring based on the slight strain at the side frame of the diaphragm filter plate can be realized.

Description

technical field [0001] The invention relates to an externally mounted optical fiber grating sensor, a detection system and a method applied to a diaphragm filter plate. Background technique [0002] Diaphragm filter press is a filtration machine that injects high-pressure fluid medium into the diaphragm filter plate to make the entire diaphragm bulge and press the filter cake to achieve dehydration of the filter cake. Diaphragm filter press has the advantages of high pressing pressure, good corrosion resistance, convenient maintenance, safety and reliability, etc. It is the first choice for industries such as metallurgy, papermaking, pharmaceuticals, food, brewing, and sewage treatment. [0003] The diaphragm filter plate used in the diaphragm filter press is composed of two diaphragms and a core plate. The external high-pressure fluid medium enters the chamber between the core plate and the diaphragm, causing the diaphragm to bulge and compress the filter cavity, thereby be...

AI Technical Summary

Problems solved by technology

[0008] (1) The fiber grating sensor embedded in the core plate of the diaphragm filter plate and the diaphragm needs to remake both molds and adjust the molding process, which makes the cost of technology upgrading high and the risk increases;

[0009] (2) Due to the large deformation of the diaphragm, the effective deformation of the fiber grating embedded in the diaphragm needs to exceed 10%, and special optical fibers need to be customized, and the upgrade cost is further increased

[0010] (3) The fiber grating sensor embedded in the core plate of the diaphragm filter plate and the complex forming process of the diaphragm is easy to dislocate, resulting in shape distortion, stress concentration and even damage, poor controllability, increased scrap rate, and high technical risk;

[0011] (4) The number of gate areas of the embedded array fiber grating sensor is large, which significantly increases the cost of key components for technology upgrading;

[0012] (5) The formed diaphragm and core plate are assembled into a complete diaphragm filter plate. The frame of the assembled diaphragm filter plate needs to be machined, such as planing and drilling. The embedded fiber grating sensor connector brings these processing A lot of inconvenience is caused, the process is complicated, and the manufacturing cost of the filter plate is increased;

[0013] (6) Once the embedded fiber grating sensor is inactivated, there is no possibility of repairing or replacing these inactivated sensors

However, due to the low strength and rigidity of the rubber base, the sensor packaged with the rubber base substrate is prone to relaxation or creep, and is not resistant to high temperature, it cannot meet the long-term high temperature environment and harsh working conditions of the filter press.

The preparation process of the metal substrate packaging patch is complicated, its own mass density is high, and the modulus of the metal substrate itself is much larger than that of the short glass fiber reinforced polypropylene matrix composite material used in the diaphragm filter plate, resulting in a high accuracy of strain transmission. The amplitude is reduced, which makes the test accuracy of the fiber grating unable to meet the requirements

[0015] In addition, during the working process of the diaphragm filter plate, its uneven working surface is constantly washed and squeezed by high-pressure and high-temperature water flow, etc., making it impossible to arrange sensors. Therefore, the external sensor patch can only be pasted on the frame of the diaphragm filter plate. The outer surface, which puts forward higher requirements for the detection accuracy and sensitivity of the sensor

Since the sensor pasted on the outer surface of the diaphragm filter plate frame can only directly monitor the strain and temperature of the frame part, it is impossible to directly obtain the strain field and temperature field of the diaphragm filter plate as a whole, and it is impossible to directly know the damage of the diaphragm filter plate. Some test and analysis systems cannot monitor the overall health status of the diaphragm filter plate in real time based on the strain and temperature of the filter plate frame

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