Electrolytic tank pull rod thread contact stress monitoring device
By embedding distributed fiber optic grating sensors and surface acoustic wave sensors in the threaded section of the electrolytic cell tie rod, and combining them with an adaptive early warning algorithm, the problem of uneven stress distribution in the tie rod thread of the electrolytic cell was solved, achieving high-precision, real-time stress monitoring and reducing leakage risk and maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2026-03-31
AI Technical Summary
Existing technologies cannot monitor the contact stress distribution of the electrolytic cell tie rod thread in real time, resulting in uneven stress distribution, which can easily lead to alkali leakage and reduced airtightness, increasing maintenance costs.
By combining distributed fiber optic grating sensors and surface acoustic wave sensors, the contact stress distribution between the tie rod and the nut is monitored in real time. Data acquisition and refreshing are achieved through the control system, and stress anomalies are captured in real time by combining adaptive early warning algorithms.
It enables multi-dimensional real-time monitoring of the stress state of the tie rod and nut, accurately detects minute stress changes, reduces the risk of leakage, extends the maintenance cycle, and reduces maintenance costs.
Smart Images
Figure CN224066247U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of alkaline electrolytic water hydrogen production equipment, concretely relates to a kind of electrolytic cell pull rod threaded contact stress monitoring device. BACKGROUND
[0002] Global hydrogen energy industry is growing rapidly under the promotion of "double carbon" target, and green hydrogen (produced by electrolyzing water through renewable energy) is considered as a key path to achieve deep decarbonization. Electrolytic cell is the core of hydrogen production system by electrolyzing water, and its reliability directly affects hydrogen production and safety. With the development of electrolytic cell towards high pressure and high current density, the uneven distribution of contact stress of pull rod and nut is increasingly prominent, which can easily cause alkali leakage and gas tightness decline. The uneven distribution of contact stress of pull rod thread: local stress concentration of pull rod thread and nut can easily lead to gasket sealing failure (especially near the end plate), causing alkali leakage and gas leakage.
[0003] Traditional technology relies on manual torque detection or static pressure sensor monitoring. Existing technology cannot analyze stress uniformity in real time, and the lack of dynamic monitoring leads to dynamic changes in stress distribution due to high temperature (60~90℃), vibration and long-term creep. Traditional methods cannot capture abnormalities in real time. Further, maintenance is lagging, and existing technology usually relies on manual inspection, which cannot prevent sudden leakage, thus increasing maintenance cost by 30%~50%.
[0004] In view of the above, it is necessary to provide an electrolytic cell pull rod threaded contact stress monitoring device to solve the above problems. UTILITY MODEL CONTENTS
[0005] The utility model aims at overcoming the defects in the prior art and providing an electrolytic cell pull rod threaded contact stress monitoring device.
[0006] To achieve the above-mentioned purpose, the technical scheme of the utility model is as follows: an electrolytic cell pull rod threaded contact stress monitoring device, comprising a pull rod and a nut, a distributed fiber grating sensor is arranged on the pull rod and the nut for measuring axial strain; further comprising a surface acoustic wave sensor arranged on the surface of the nut for monitoring the shear stress on the surface of the nut; the distributed fiber grating sensor and the surface acoustic wave sensor are electrically connected with the control system, and the sensor data acquisition and refresh rate are controlled by the control system to be 1-20Hz.
[0007] Further, a first FBG sensor group is arranged on the pull rod, the first FBG sensor group comprises a plurality of FBG sensor monomers for independently collecting data, the first FBG sensor group is arranged from the thread root of the end of the pull rod, and a spacing distance is provided between adjacent sensor monomers.
[0008] Further, the nut is provided with a plurality of second FBG sensor groups on the side of the contact surface, and the second FBG sensor group comprises a plurality of FBG sensor monomers for collecting data independently.
[0009] Further, the first FBG sensor group and the second FBG sensor group are embeddedly installed.
[0010] Further, the interval distance of the FBG sensor monomers in the first FBG sensor group is 1-2mm.
[0011] Further, the FBG sensor monomers in the second FBG sensor group are arranged in multiple numbers around the contact surface of the nut.
[0012] Further, the surface of the FBG sensor monomers of the first FBG sensor group and the second FBG sensor group is provided with a protective coating, so that the temperature resistance of the FBG sensor monomers is ≤300℃, and the alkali resistance is pH≥12.
[0013] Further, the surface acoustic wave sensor is attached to each side surface of the nut, is connected with a wireless radio frequency, and reads the local shear stress of the nut through the wireless radio frequency; and the surface acoustic wave sensor is packaged in a ceramic shell, so that the pressure bearing capacity of the surface acoustic wave sensor is ≥10MPa.
[0014] Further, the spatial resolution accuracy of the surface acoustic wave sensor reaches ±0.1mm.
[0015] The stress monitoring device of the utility model has the advantages and beneficial effects that the patent proposes a stress monitoring device integrating fiber Bragg grating (FBG) and surface acoustic wave (SAW), combines a dynamic stress distribution model and a self-adaptive early warning algorithm, and realizes real-time monitoring of the contact stress distribution of the pull rod and the nut, effectively prevents leakage, and ensures the air tightness of the electrolytic cell.
[0016] The distributed fiber Bragg grating sensor is embedded at the thread root of the pull rod of the electrolytic cell and the contact surface of the nut to measure the axial strain, and the surface acoustic wave sensor is attached to the surface of the nut to measure the local shear stress, so that multi-dimensional real-time monitoring of the stress state of the pull rod and the nut is realized. The two sensors complement each other, can fully capture the stress distribution, and avoid the limitations of single sensor monitoring.
[0017] The FBG sensor spacing is 1-2mm, 8-12 FBG sensors are arranged on each pull rod, the axial strain measurement accuracy can reach ±0.5%, the spatial resolution of the surface acoustic wave sensor reaches ±0.1mm, and the data can be read through the wireless radio frequency, so that high resolution and high accuracy of stress measurement are ensured, and small stress changes can be accurately detected.
[0018] The FBG strain data and the SAW shearing stress data are synchronized in real time, and a three-dimensional stress distribution cloud picture is constructed, and the refresh rate is greater than or equal to 10Hz. This enables the operator to intuitively understand the stress distribution of the pull rod and the nut in real time, and timely find abnormal problems such as stress concentration, and provides strong support for timely measures. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 is a structural schematic diagram of the electrolytic tank pull rod threaded contact stress monitoring device of the utility model;
[0020] In the figure: 1, end plate; 2, pull rod; 3, nut; 4, FBG sensor single body; 5, surface acoustic wave sensor; 6, first FBG sensor group; 7, interval distance; 8, second FBG sensor group; 9, protective coating; 10, ceramic shell. DETAILED DESCRIPTION
[0021] The specific embodiments of the utility model are further described below in combination with the drawings and examples. The following examples are only used to more clearly illustrate the technical scheme of the utility model, and cannot limit the protection scope of the utility model.
[0022] An electrolytic tank pull rod threaded contact stress monitoring device, as shown in Figure 1 The device includes a pull rod 2 and a nut 3, and distributed fiber grating sensors are arranged on the pull rod 2 and the nut 3 for measuring axial strain. The device also includes a surface acoustic wave sensor arranged on the surface of the nut 3 for monitoring the shearing stress on the surface of the nut 3. The distributed fiber grating sensors and the surface acoustic wave sensor 5 are electrically connected to a control system, and the control system controls the sensor data acquisition and refresh rate of 1-20Hz.
[0023] Specifically, the first FBG sensor group 6 is arranged on the pull rod 2, the first FBG sensor group 6 includes a plurality of FBG sensor units 4 for independently collecting data, the first FBG sensor group 6 is arranged from at least the thread root of the end of the pull rod 2, and a spacing distance 7 is arranged between adjacent sensor units. In actual use, 8-12 FBG sensor units 4 are arranged in sequence and uniformly spaced at the thread root of the pull rod 2, each FBG sensor unit 4 is regarded as a monitor unit for measuring the axial stress, so that the measurement accuracy of the axial strain of the pull rod 2 can reach ±0.5%, so that the deformation of the pull rod 2 in the axial direction and the deformation amount can be accurately perceived. Similarly, a plurality of second FBG sensor groups 8 are arranged on the nut 3 on the side of the contact surface, the second FBG sensor group 8 includes a plurality of FBG sensor units 4 for independently collecting data. As shown in the figure, the first FBG sensor group 6 and the second FBG sensor group 8 are embeddedly installed. Moreover, in order to improve the adaptability of the distributed fiber grating sensor to the working condition of the electrolytic cell, the FBG sensor units 4 of the first FBG sensor group 6 and the second FBG sensor group 8 are provided with a protective coating 9, the protective coating 9 is made of polyimide material, the FBG sensor unit 4 can resist a temperature of ≤300℃, and the alkali resistance can reach pH≥12.
[0024] In actual work, when the internal pressure of the electrolytic cell changes and other factors may cause the axial tension of the pull rod 2 to change, the distributed fiber grating sensor arranged on the pull rod 2 is used to sense the influence of the tension on the length change of the pull rod 2. The distributed fiber grating sensor is sensitive to the small change in length, and by measuring the axial length change (i.e. the axial strain), it can be known that the pull rod 2 has been subjected to a force in the axial direction, and whether the force is within the normal range. If the axial strain of the pull rod 2 at a certain position is suddenly much larger than that at other positions, it may mean that the local stress at this position is concentrated, for example, there may be a small defect in the structure of the thread root at this position, causing the deformation at this position to be particularly obvious when subjected to stress, so that the stress on the pull rod 2 can be well monitored. Similarly, for the nut 3, since the FBG sensor units 4 in the second FBG sensor group 8 are arranged in multiple around the contact surface of the nut 3, if the detection values of the FBG sensor units 4 on the contact surface side of the nut 3 are obviously different in actual use, it means that the nut 3 is subjected to uneven stress, and is prone to fatigue damage under the action of long-term variable working conditions. The technical personnel can adjust or replace the pull rod 2 and the nut 3 according to the analysis of the monitoring value.
[0025] In the embodiment, the spacing distance 7 of the FBG sensor units 4 in the first FBG sensor group 6 is preferably 1-2 mm.
[0026] Further, the surface acoustic wave sensor 5 is attached to each side surface of the nut 3 and connected with the radio frequency identification (RFID), and the local shear stress of the nut 3 is read through the radio frequency identification. When the force on the nut 3 is uneven, the shear force of each side surface of the nut 3 increases, and the surface acoustic wave sensor 5 monitors the shear change of the nut 3 on the surface of the nut 3. In the electrolytic tank, when the nut 3 is subjected to uneven force from each direction, the surface of the nut 3 will have a deformation trend under the action of shear force. The surface acoustic wave sensor 5 can capture the extremely small deformation information of the surface of the nut 3 due to the shear force through the radio frequency identification technology, and the spatial resolution can reach ±0.1 mm, so the size and position of the local shear stress can be accurately measured. If the shear stress measured by the surface acoustic wave sensor 5 in a certain area of the surface of the nut 3 is obviously higher than that in the surrounding area, it indicates that there is local stress concentration in this area.
[0027] Further, the surface acoustic wave sensor 5 is packaged in the aluminum nitride ceramic shell 10, so that the pressure bearing capacity of the surface acoustic wave sensor 5 is ≥10 MPa, thereby improving the pressure resistance of the surface acoustic wave sensor 5 and improving its applicability in high-pressure environment.
[0028] The local stress concentration is determined by the above two kinds of data.
[0029] Specifically, when the distributed fiber grating sensor measures the axial strain of a certain section of the pull rod 2 to be obviously higher than that at other positions, and the local shear stress measured by the corresponding position of the surface acoustic wave sensor 5 also abnormally increases, it can be highly suspected that there is local stress concentration in the threads of the pull rod 2 and the nut 3 at this position. Because under normal circumstances, the stress on the pull rod 2 and the nut 3 should be relatively uniform, and the strain and shear stress data at each position will not have too much difference. For example, at a certain position, the distributed fiber grating sensor shows that the axial strain exceeds the average strain value by 20%, and the shear stress measured by the surface acoustic wave sensor 5 is 3 times that of the surrounding area, which strongly suggests that there is a problem of local stress concentration at this position.
[0030] The adverse effects of the two stresses on the pull rod 2 include: if there is local stress concentration at the threads of the pull rod 2, the pull rod 2 at the position of stress concentration is prone to fatigue damage in a long-term state. The same is true for the pull rod 2, cracks may appear at the position of local stress concentration, and with the passage of time, the cracks will gradually expand, and eventually may lead to the fracture of the pull rod 2, causing the structural integrity of the electrolytic tank to be damaged. Moreover, the excessive axial strain may cause the pull rod 2 to be permanently deformed, affecting its fastening effect on the components of the electrolytic tank, and further affecting the normal operation of the electrolytic tank.
[0031] Two kinds of stress influence on electrolytic cell: for electrolytic cell, the local stress concentration of pull rod 2 thread and nut 3 can cause gasket seal failure. Because the local stress concentration can make the gasket be unevenly extruded, some parts of the gasket can be damaged by excessive extrusion, and some parts can be sealed due to insufficient extrusion.
[0032] By controlling the system to synchronize the FBG strain data and the SAW shear stress data in real time, the refresh rate of the data can be >=10Hz, and a three-dimensional stress distribution cloud diagram is constructed according to the collected data. In the assembly stage of the electrolytic cell, the step pressure (0~2MPa) is applied through the hydraulic loading device, the stress-wavelength / frequency response curves of FBG and SAW are recorded, and the initial stress distribution reference is established. According to the stress distribution model, the service life of the gasket seal is predicted, and the inspection cycle is dynamically adjusted (from fixed 1 month / time to on-demand triggering).
[0033] According to the data analysis, the leakage risk classification is established: first-level warning (stress change rate between adjacent sensors >5% / mm): prompt local stress unevenness, and suggest checking the torque of nut 3; second-level alarm (stress change rate between adjacent sensors >10% / mm): automatic shutdown and positioning of the leakage risk point.
[0034] The electrolytic cell pull rod 2 thread contact stress monitoring device realizes the following advantages:
[0035] 1. High-precision monitoring: the stress distribution resolution is up to ±0.1MPa, which can detect micron-level thread deformation (the accuracy is 10 times higher than that of traditional torque wrench).
[0036] 2. Real-time and reliability: the data refresh rate is up to 10Hz, the delay is <50ms, and it is suitable for dynamic load fluctuation of electrolytic cell (such as start-stop impact of green electricity hydrogen production).
[0037] 3. Reduced maintenance cost: leakage accidents are reduced by 90%, the maintenance cycle is extended to 1 year, and the comprehensive cost is reduced by 20%.
[0038] Through the cooperative monitoring of FBG+SAW and the SUI early warning algorithm, through the specific layout of the sensor, combined with the algorithm logic, and supplemented by structural reinforcement integration, a whole system is constructed, which realizes the overall monitoring of the electrolytic cell from hardware to software, and provides a standardized solution for the safe operation and maintenance of the electrolytic cell.
[0039] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled persons in the technical field, without departing from the technical principles of the present application, some improvements and refinements can be made, and these improvements and refinements should be regarded as the protection scope of the present application.
Claims
1. A device for monitoring the contact stress of the threads of a tie rod of an electrolytic cell, comprising a tie rod (2) and a nut (3), characterized in that, Distributed fiber Bragg grating sensors are arranged on the pull rod (2) and the nut (3) to measure axial strain; a surface acoustic wave sensor is arranged on the surface of the nut (3) to monitor the shear stress on the surface of the nut (3); the distributed fiber Bragg grating sensor and the surface acoustic wave sensor (5) are electrically connected to the control system, and the control system controls the sensor data acquisition and refresh rate of 1-20Hz.
2. A cell rod threaded contact stress monitoring device according to claim 1, wherein, The first FBG sensor group (6) is arranged on the pull rod (2), the first FBG sensor group (6) includes a plurality of FBG sensor monomers (4) for independently collecting data, the first FBG sensor group (6) is arranged from the thread root of the end of the pull rod (2), and a spacing distance (7) is arranged between adjacent sensor monomers.
3. A cell rod threaded contact stress monitoring device according to claim 2, characterised in that, The nut (3) is provided with a plurality of second FBG sensor groups (8) on the contact surface side, and the second FBG sensor group (8) includes a plurality of FBG sensor monomers (4) for independently collecting data.
4. A cell rod threaded contact stress monitoring device according to claim 3, wherein, The first FBG sensor group (6) and the second FBG sensor group (8) are embeddedly installed.
5. A cell rod threaded contact stress monitoring device according to claim 2, wherein, The spacing distance (7) of the FBG sensor monomer (4) in the first FBG sensor group (6) is 1-2mm.
6. A cell rod threaded contact stress monitoring device according to claim 3, wherein, The FBG sensor monomers (4) in the second FBG sensor group (8) are arranged in multiple around the contact surface of the nut (3).
7. A cell rod threaded contact stress monitoring device according to claim 3, wherein, The surface of the FBG sensor monomer (4) of the first FBG sensor group (6) and the second FBG sensor group (8) is provided with a protective coating (9).
8. A cell rod threaded contact stress monitoring device according to claim 1 wherein, The surface acoustic wave sensor (5) is attached to each side surface of the nut (3), and is connected with a wireless radio frequency, and reads the local shear stress of the nut (3) through the wireless radio frequency; the surface acoustic wave sensor (5) is packaged in a ceramic shell (10).
9. A cell rod threaded contact stress monitoring device according to claim 8, characterised in that, The spatial resolution accuracy of the surface acoustic wave sensor (5) reaches ±0.1mm.