A real-time online monitoring method for the weak magnetic field of optical fibers in the steel wire rope of a winding hoist

Abstract

The present invention discloses a real-time online monitoring method for a wire rope of a winding hoist by combining optical fiber and weak magnetic field, which includes the following steps: An optical fiber cable coaxial with the wire rope is arranged inside the core of the wire rope, and the optical fiber cable is kept coaxial and straight with the core through the parallel lay process; During the operation of the wire rope driven by the hoist, the stress data of each position of the wire rope is collected in real time by the optical fiber sensors arranged in the optical fiber cable and transmitted to the processor. By combining optical fiber stress monitoring with weak magnetic damage detection, and by arranging an optical fiber cable and optical fiber sensors in the wire rope, the stress data of each position of the wire rope can be collected in real time, so as to realize the overall state monitoring of the wire rope. Moreover, when abnormal stress changes are detected, a quick response can be made and detailed and accurate flaw detection can be carried out through a weak magnetic detection device, which can effectively prevent safety accidents caused by reasons such as wire breakage, wear, corrosion, and fatigue of the wire rope, and greatly improve the use safety of the wire rope of the hoist.

Description

Technical Field

[0001] The present invention relates to the technical field of wire rope monitoring, and specifically provides a real-time online monitoring method for the wire rope of a winding hoist by combining optical fiber and weak magnetic field. Background Art

[0002] The weak magnetic field detection technology is a major innovation achievement made by Chinese scientists in the field of wire rope detection after successfully discovering the changes and movement laws of the spatial magnetic field vector situation. Especially the newly developed TCK.W portable non-destructive flaw detector for wire ropes has overcome two major technical problems in the field of non-destructive wire rope detection and achieved two major breakthroughs: one is that it can quantitatively detect various damages such as broken wires, wear, corrosion, and fatigue of in-service wire ropes, and the other is that it can correctly evaluate the remaining load-bearing capacity and service life of the measured wire ropes. Compared with traditional manual detection, this wire rope online automatic monitoring system greatly improves the safety of detection personnel, the stability of detection data, and the detection efficiency. However, it still has the following defects: the detection method is single, and since the wire rope needs to continuously pass through the monitoring device during detection, and the weak magnetic induction is used to monitor the state of the wire rope section by section, it is impossible to monitor the overall state of the wire rope in real time and comprehensively, resulting in a certain lag in the safety monitoring of the wire rope and affecting the use safety of the wire rope and hoist equipment. Therefore, we propose a real-time online monitoring method for the wire rope of a winding hoist by combining optical fiber and weak magnetic field. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects and provide a real-time online monitoring method for the wire rope of a winding hoist by combining optical fiber and weak magnetic field. By setting an optical fiber cable and an optical fiber sensor inside the wire rope, the stress data of each position of the wire rope can be collected in real time, thereby realizing the overall state monitoring of the wire rope, and effectively solving the problems in the background art.

[0004] To achieve the above object, the present invention provides the following technical solution: A real-time online monitoring method for the wire rope of a winding hoist by combining optical fiber and weak magnetic field, comprising the following steps:

[0005] S1) Set an optical fiber cable coaxial with the wire rope core inside the wire rope core, and the optical fiber cable is kept coaxial and straight with the wire rope core through the parallel lay process;

[0006] S2) During the operation of the wire rope driven by the hoist, the stress data of each position of the wire rope are collected in real time by the optical fiber sensors arranged inside the optical fiber cable and transmitted to the processor;

[0007] S3) Fix a weak magnetic detection device on the main equipment side of the hoist. The weak magnetic detection device is sleeved on the steel wire rope. When the hoist drives the steel wire rope to run, collect the magnetic energy potential difference information on the steel wire rope, quantitatively analyze the damage such as broken wires, wear, corrosion, and fatigue of the steel wire rope, and transmit the corresponding data to the processor;

[0008] S4) Before the steel wire rope is officially put into use, conduct a full-section detection through the weak magnetic detection device. After the detection shows no damage, put it into use;

[0009] S5) During the operation of the hoist, when the optical fiber sensor detects that the stress change value of the steel wire rope exceeds the preset threshold, trigger an alarm, automatically control or manually intervene to stop the hoist from running under load, and control the hoist to drive the steel wire rope to move to the weak magnetic detection device for secondary detection.

[0010] As a preferred technical solution of the present invention, the following steps are further included: S6) After the steel wire rope has been in use for a period of time, the weak magnetic detection device is set to a continuous monitoring mode, continuously collect the magnetic energy potential difference information on the steel wire rope, and conduct a spatio-temporal correlation analysis of the magnetic characteristic data and the optical fiber stress data through the processor.

[0011] As a preferred technical solution of the present invention, a flexible protective sleeve is sleeved on the outer surface of the optical fiber cable.

[0012] As a preferred technical solution of the present invention, a protective coating is applied to the outer surface of the protective sleeve.

[0013] As a preferred technical solution of the present invention, fiber strands are arranged on the outside of the protective coating, and the core of the steel wire rope is arranged outside the fiber strands.

[0014] As a preferred technical solution of the present invention, the steel wire rope further includes a plurality of outer wire strands arranged outside the core.

[0015] As a preferred technical solution of the present invention, a plurality of weak magnetic detection modules and two groups of wide-angle cameras are arranged inside the weak magnetic detection device, and the two groups of wide-angle cameras are respectively arranged at both ends of the plurality of weak magnetic detection modules.

[0016] As a preferred technical solution of the present invention, two long rods and two short rods are respectively arranged on both sides of the shell of the weak magnetic detection device, and a guide wheel is arranged on each of the long rod and the short rod. The four guide wheels are respectively arranged at the upper and lower ends on both sides of the shell of the weak magnetic detection device.

[0017] As a preferred technical solution of the present invention, the preset threshold in step S5) includes a dynamic change threshold and a static stress threshold, wherein the dynamic change threshold is that the stress change rate in adjacent sampling periods exceeds 10% / s.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: by arranging optical cables and optical fiber sensors in the wire rope, stress data at various positions of the wire rope can be collected in real time, thereby realizing overall state monitoring of the wire rope, and when abnormal stress changes are detected, a quick response can be made and detailed and accurate flaw detection can be performed through a weak magnetic detection device, which can effectively prevent safety accidents caused by wire breakage, wear, rust, fatigue, etc. of the wire rope, greatly improving the safety of the use of the hoist wire rope.

[0019] Combining optical fiber stress monitoring with weak magnetic damage detection forms a collaborative mode of "real-time global monitoring + triggered local precision inspection". At the same time, the trigger logic is optimized: the stress change threshold of optical fiber monitoring triggers the weak magnetic secondary detection, avoiding the high energy consumption problem of continuous operation of weak magnetic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the cross-sectional structure of the steel wire rope of the present invention;

[0021] Figure 2 It is a schematic diagram of the structure of the steel wire rope and the weak magnetic detection device of the present invention.

[0022] In the figure: 1 rope core, 2 outer steel wire strands, 3 optical fiber cable, 4 optical fiber sensor, 5 protective casing, 6 protective coating, 7 fiber strands, 8 steel wire rope, 9 weak magnetic detection device, 10 weak magnetic detection module, 11 wide-angle camera, 12 long rod, 13 short rod, 14 guide wheel. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] See also Figure 1-2 The present invention provides a technical solution: a real-time online monitoring method for the weak magnetic combination of optical fiber of a winding hoist wire rope, comprising the following steps:

[0025] S1) A coaxial optical fiber cable 3 is arranged inside the rope core 1 of the steel wire rope 8. The optical fiber cable 3 can be arranged in 1 to 3 bundles. The optical fiber cable 3 is twisted synchronously with the rope core 1 at a twist angle of 0.5-1.5° through a parallel twisting process to ensure that the optical fiber cable 3 is in a straight extension state inside the rope core 1, and torsion of the optical fiber cable 3 and the influence on communication sensing are avoided as much as possible.

[0026] The optical fiber cable 3 uses a double-layer acrylic-coated bending-resistant optical fiber, with a bending radius tolerance of ≥5 mm and a tensile strength of ≥100 kpsi.

[0027] The optical fibers of the optical fiber cable 3 can select optical fibers with a relatively high modulus of elasticity, such as plastic optical fibers, single crystal sapphire optical fibers, composite silicon carbide fibers, metal-coated optical fibers, etc. For metal-coated optical fibers, a 10-20 μm titanium alloy layer can be sputtered on the surface of the optical fiber to increase the modulus of elasticity of the optical fiber, so as to avoid the modulus of elasticity of the optical fiber being less than that of the wire rope and causing breakage during use.

[0028] S2) During the operation of the wire rope 8 driven by the hoist, the stress data of each position of the wire rope 8 are collected in real time through the optical fiber sensor 4 arranged in the optical fiber cable 3 and transmitted to the processor for analysis, processing and judgment by the processor.

[0029] A rotating optical fiber coupler is set on the main equipment side of the hoist. The end of the optical fiber cable 3 is optically connected to the signal processing unit through this coupler. When the wire rope 8 operates, the axial stress distribution data of the wire rope are collected in real time through the optical fiber sensor 4 at a sampling frequency of 100-500 Hz.

[0030] The optical fiber sensor 4 is preferably a fiber Bragg grating sensor (FBG). A grating is inscribed in the optical fiber. The fiber Bragg grating sensor forms a periodic refractive index change in the fiber core and directly senses temperature / strain, etc.; a distributed optical fiber sensor (DTS / DAS) can also be used to detect the strain of the wire rope 8 by utilizing the Rayleigh / Raman scattering effect of the optical fiber itself.

[0031] The processor can be selected as a single-chip microcomputer of the STM32H743 series, which is suitable for the acquisition and preliminary processing of real-time stress data; an industrial-grade processor such as Intel Atom x6425E can also be selected. Through AI-driven damage type recognition and three-dimensional stress model operation, it is suitable for scenarios that require the establishment of a three-dimensional stress model. It integrates an AI acceleration instruction set (Intel DL Boost) through a quad-core processor (1.8 GHz), can run machine learning algorithms (such as the wire rope damage determination model), and supports operation in a wide temperature range of -40~85°C, adapting to the harsh environment of the mine.

[0032] S3) A weak magnetic detection device 9 is fixedly arranged on the main equipment side of the hoist. The weak magnetic detection device 9 is sleeved on the wire rope 8. When the hoist drives the wire rope 8 to operate, the magnetic potential difference information on the wire rope 8 is collected, and the damage such as broken wires, wear, corrosion, and fatigue of the wire rope 8 is quantitatively analyzed and the corresponding data is transmitted to the processor.

[0033] The weak magnetic detection device 9 is provided with a weak magnetic detection module 10, etc. As a whole, it can select the TCK.W wire rope online automatic detection system and equipment sold by Luoyang Willrop Detection Technology Co., Ltd. Its technical principle is as follows: By detecting the equal, uniform, and continuous distribution of the magnetic energy product established along the axial direction of the wire rope by the detection device, the magnetic energy product in any volume element should also be equal and uniform. The magnetic field line density is the same, the magnetic flux is equal, and a given memory magnetic field is formed. The memory magnetic field will not disappear with the withdrawal of the external magnetic field. As long as there are no conditions such as severe mechanical vibration or high temperature, it will exist stably for a long time. By collecting the magnetic energy potential difference information on the wire rope 8, quantitative analysis is carried out on the damage such as broken wires, wear, corrosion, and fatigue of the wire rope 8.

[0034] S4) When the wire rope 8 is initially installed, it continuously passes through the weak magnetic detection device 9 at a speed of 0.2 - 0.5 m / s to establish a full-length reference map including magnetic anisotropy characteristics. When the local magnetic signal deviation is less than 2%, it is judged as qualified. After the whole section is detected by the weak magnetic detection device 9 and no damage is detected, it is put into use. If there is damage, the wire rope 8 is replaced or further detected manually and the impact on the safe operation of the hoist is evaluated before further treatment.

[0035] S5) During the operation of the hoist, when the optical fiber sensor 4 detects that the stress change value of the wire rope 8 exceeds the preset threshold, an alarm is triggered, and the hoist is automatically controlled or manually intervened to stop the load operation, and the hoist is controlled to drive the wire rope 8 to move to the weak magnetic detection device 9 for secondary detection.

[0036] The preset threshold includes a dynamic change threshold and a static stress threshold, where the dynamic change threshold is that the stress change rate in adjacent sampling periods exceeds 10% / s.

[0037] The slow damage change of the wire rope may not exceed the preset static threshold, resulting in undetectability. Therefore, the stress detection of the wire rope can comprehensively compare the stress values in each time period and usage state, etc., to achieve the purpose of accurate detection.

[0038] Specifically: During the operation of the hoist, when the optical fiber sensor 4 detects any of the following conditions, a hierarchical alarm is triggered:

[0039] The instantaneous value of the single-point stress exceeds 50 - 60% of the calibrated value of the wire rope breaking strength;

[0040] The stress gradient change rate in the adjacent 1m section exceeds 8 - 12% / s;

[0041] The stress fluctuation amplitude within 3 consecutive sampling periods exceeds 15 - 20% of the average stress;

[0042] After being triggered, the following is automatically executed:

[0043] a. Cut off the power supply of the hoist load and start the braking device;

[0044] b. Drive the wire rope 8 at a speed of 0.3 - 0.8 m / s through the weak magnetic detection device 9, and at the same time increase the sampling frequency of the magnetic sensor to 2 - 5 kHz for precise damage positioning. Determine whether there is damage to this section of the wire rope. If there is damage, replace the wire rope; if no damage is detected, further inspection shall be carried out manually to determine the cause of stress change, etc.

[0045] S6) After the wire rope 8 has been in use for a period of time (400 - 1600 h), damage may occur on the surface of the wire rope 8 while the stress change monitored by the fiber optic sensor is not obvious. Set the weak magnetic detection device 9 to the continuous monitoring mode, continuously collect the magnetic potential difference information on the wire rope 8, and perform spatio - temporal correlation analysis on the magnetic characteristic data and the fiber optic stress data through the processor. Synchronize the time stamps of the fiber optic stress data and the magnetic detection data and match the spatial positions. Ensure the safety of the wire rope 8 during use.

[0046] Optionally, the following steps are also included: Establish a three - dimensional stress model of the wire rope, compare and analyze the real - time stress data with the model prediction values, and trigger an abnormal warning when the deviation exceeds 10 - 15%. The three - dimensional stress model is constructed through machine learning algorithms, and the training data includes wire rope specification parameters, load condition data, historical detection data, etc.

[0047] In a preferred technical solution, a flexible protective sleeve 5 is sleeved on the outer surface of the fiber optic cable 3. The protective sleeve 5 can be selected from the commonly used protective sleeves for the fiber optic cable 3 to protect the fiber optic cable 3. The protective sleeve 5 can also adopt a double - layer composite structure: the inner layer is thermoplastic polyurethane (TPU), and the thickness can be selected as 0.3 - 0.5 mm; the outer layer can be an aramid fiber braided reinforcement layer with a braiding density ≥ 60 meshes per inch, which can absorb the shear stress generated when the wire rope bends and improve the tensile strength of the fiber optic cable 3. The composite protective structure can also reduce the micro - bending loss of the optical fiber.

[0048] In a preferred technical solution, a protective coating 6 is coated on the outer surface of the protective sleeve 5.

[0049] The protective coating 6 can be selected as a polyurea coating layer, which has excellent physical and chemical properties, good tensile strength, elongation rate, flexibility, wear resistance, aging resistance, corrosion resistance, etc., and has good thermal stability and can be used for a long time at 120 °C.

[0050] The protective coating 6 can also be selected as a polyurethane - fluorocarbon composite material layer. The fluorocarbon coating extends the salt spray corrosion resistance time, and the surface self - cleaning function reduces the dirt adhesion rate by 80%.

[0051] In a preferred technical solution, a fiber strand 7 is provided outside the protective coating 6, the rope core 1 of the wire rope 8 is arranged outside the fiber strand 7, the fiber strand 7 can be made of high modulus polyethylene (HMPE) fiber with a single filament diameter of 0.12 - 0.15 mm, and is wound around the outside of the protective coating 6 at a cross angle of ±15°, with the winding tension controlled at 50 - 80 N. The difference in elastic modulus between the HMPE fiber and the steel wire strand (HMPE: 120 GPa vs steel wire: 210 GPa) forms a gradient buffer layer, reducing the local stress concentration by 40%.

[0052] The wire rope 8 further includes a plurality of outer wire strands 2 arranged outside the rope core 1. The multi-layer wire strands 2 can be of 6×36WS structure, with a wire diameter of 0.25 - 0.35 mm and a spacing of 1 - 1.5 mm from the fiber strand 7.

[0053] In a preferred technical solution, a plurality of weak magnetic detection modules 10 and two groups of wide-angle cameras 11 are provided inside the weak magnetic detection device 9. The wide-angle cameras 11 can use a global shutter CMOS sensor with a 200° field of view, a resolution of 1280×1024, and a frame rate that can be synchronized with or greater than the moving speed of the wire rope. The two groups of wide-angle cameras 11 are respectively arranged at both ends of the plurality of weak magnetic detection modules 10. Whether the wire rope 8 is wound upward or moves downward, once the weak magnetic detection module 10 detects a damage to the wire rope, the wide-angle camera 11 on the side of the moving direction can take a picture of the damaged section, and then transmit it to an external display through a processor for the reference of the staff.

[0054] The detection surface of the weak magnetic detection module 10 maintains a spacing of 20 - 50 mm from the running track of the wire rope 8, and the wide-angle camera 11 also maintains a spacing of 20 - 50 mm from the running track of the wire rope 8 to facilitate taking pictures of the damaged section of the wire rope 8.

[0055] The wide-angle cameras 11, weak magnetic detection devices 9, processors, fiber optic sensors, etc. used in this application are all common electronic components in the prior art. Their specific structures, working principles, and circuit connections are all well-known technologies and will not be described in detail here.

[0056] In a preferred technical solution, two groups of long rods 12 and short rods 13 are respectively arranged on both sides of the outer shell of the weak magnetic detection device 9. A guide wheel 14 is respectively arranged on the long rod 12 and the short rod 13. The four guide wheels 14 are respectively arranged at the upper and lower ends on both sides of the outer shell of the weak magnetic detection device 9. Both the long rod 12 and the short rod 13 are made of 7075 aluminum alloy, with the length of the long rod L = 300 - 500 mm and the length of the short rod l = 150 - 250 mm; the surface of the guide wheel 14 is coated with a polyurethane layer, and an adaptive displacement of ±5 mm is realized through a spring buffer mechanism. The wire rope 8 is guided by the guide wheel 14 to maintain the stability of the weak magnetic detection device 9.

[0057] The parts not disclosed in the present invention are all prior arts, and their specific structures, materials and working principles will not be elaborated herein. Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A real-time online monitoring method for optical fiber weak magnetic bonding of a winding hoist wire rope, characterized in that: The following steps are involved: S1) arranging a coaxial optical fiber cable (3) in a rope core (1) of a steel wire rope (8), wherein the optical fiber cable (3) is kept coaxial and straight with the rope core (1) by a parallel twisting process; S2) when the hoist drives the steel wire rope (8) to run, the optical fiber sensor (4) arranged in the optical fiber cable (3) collects stress data of each position of the steel wire rope (8) in real time and transmits the data to the processor; S3) a weak magnetic detection device (9) is fixedly arranged on the main equipment side of the hoist, the weak magnetic detection device (9) is sleeved on the steel wire rope (8), and when the hoist drives the steel wire rope (8) to run, magnetic energy potential difference information on the steel wire rope (8) is collected, and wire breakage, wear, rust, and fatigue damage of the steel wire rope (8) are quantitatively analyzed and the corresponding data is transmitted to the processor; S4) Before the steel wire rope (8) is put into use, it is fully inspected by a weak magnetic detection device (9) and put into use only after it is found to be free of damage; S5) During the operation of the hoist, when the optical fiber sensor (4) detects that the stress change value of the steel wire rope (8) exceeds a preset threshold value, an alarm is triggered, and the hoist is automatically controlled or manually intervened to stop the load operation, and the hoist is controlled to drive the steel wire rope (8) to move to the weak magnetic detection device (9) for secondary detection.

2. A method for real-time online monitoring of optical fiber weak magnetic bonding of a winding hoist wire rope according to claim 1, characterized in that: The following steps are also included: S6) After the steel wire rope (8) has been in use for a period of time, the weak magnetic detection device (9) is set to a continuous monitoring mode to continuously collect magnetic energy potential difference information on the steel wire rope (8), and perform spatiotemporal correlation analysis on the magnetic characteristic data and the optical fiber stress data through a processor.

3. According to claim 1, a real-time online monitoring method for optical fiber weak magnetic combination of a winding hoist wire rope is characterized in that: The outer surface of the optical fiber cable (3) is sleeved with a flexible protective sleeve (5).

4. A method for real-time online monitoring of optical fiber weak magnetic bonding of a winding hoist wire rope according to claim 3, characterized in that: The outer surface of the protective sleeve (5) is coated with a protective coating (6).

5. A method for real-time online monitoring of optical fiber weak magnetic bonding of a winding hoist wire rope according to claim 4, characterized in that: Fiber strands (7) are arranged on the outside of the protective coating (6), and the rope core (1) of the steel wire rope (8) is arranged on the outside of the fiber strands (7).

6. A method for real-time online monitoring of optical fiber weak magnetic bonding of a winding hoist wire rope according to claim 5, characterized in that: The steel wire rope (8) further comprises a plurality of outer steel wire strands (2) arranged outside the rope core (1).

7. The method for real-time online monitoring of optical fiber weak magnetic bonding of a winding hoist wire rope according to claim 1 is characterized in that: A plurality of weak magnetic detection modules (10) and two groups of wide-angle cameras (11) are arranged inside the weak magnetic detection device (9), and the two groups of wide-angle cameras (11) are respectively arranged at two ends of the plurality of weak magnetic detection modules (10).

8. The method for real-time online monitoring of optical fiber weak magnetic bonding of a winding hoist wire rope according to claim 1 is characterized in that: Two groups of long rods (12) and short rods (13) are respectively arranged on both sides of the outer shell of the weak magnetic detection device (9); a guide wheel (14) is respectively arranged on the long rod (12) and the short rod (13); and the four guide wheels (14) are respectively arranged at the upper and lower ends of both sides of the outer shell of the weak magnetic detection device (9).

9. The method for real-time online monitoring of optical fiber weak magnetic bonding of a winding hoist wire rope according to claim 1, characterized in that: The preset threshold in step S5) includes a dynamic change threshold and a static stress threshold, wherein the dynamic change threshold is when the stress change rate between adjacent sampling periods exceeds 10% / s.

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