Mechanical seal end face friction torque monitoring device and abnormity monitoring method

Abstract

The invention discloses a mechanical sealing end face friction torque monitoring device and an abnormity monitoring method. The mechanical sealing end face friction torque monitoring device comprises a sealing shell, a shaft sleeve, a movable ring, a static ring, a torque sensitive shaft sleeve, a strain sensor and a signal transmission assembly. The static ring and the sealing shell are kept static; the shaft sleeve, the moving ring, the torque sensitive shaft sleeve, the strain sensor and the signal transmission assembly rotate synchronously and transmit end face friction torque. The strain sensor is suitable for monitoring the strain condition of the torque sensitive shaft sleeve when the end face friction torque changes. The signal transmission assembly is connected with the strain sensor so as to be suitable for transmitting and receiving strain signals of the strain sensor. The change condition of the end face friction torque can be obtained by monitoring the strain of the torque sensitive shaft sleeve, and abnormal signals can be judged and recognized; the device is simple in structure and easy to install and calibrate; the method is not easily influenced by high temperature, high pressure, media and other environmental factors, the monitoring process is stable, and the monitoring result is high in accuracy and reliability.

Description

Technical Field

[0001] The present application relates to the technical field of friction torque monitoring of mechanical seals, and in particular to a mechanical seal end face friction torque monitoring device and an abnormality monitoring method. Background Art

[0002] Mechanical seal end face friction torque refers to the torque generated by friction between the dynamic and static seal faces in a mechanical seal. When the equipment is operating, the dynamic ring rotates with the shaft while the static ring remains stationary. Friction is generated between the two seal faces, and this force acts on the average radius, creating torque.

[0003] During long-term operation of mechanical seals, friction torque is a core parameter reflecting the condition and lifespan of the end face. End face wear, lubrication failure, or thermal deformation can lead to increased surface roughness and uneven contact stress distribution, directly causing increased friction torque. End face friction torque is related to the equipment's energy consumption, sealing performance, and the degree of wear on the sealing components. Real-time monitoring of friction torque changes allows for accurate assessment of seal health and fault warnings: Steady torque growth indicates gradual wear, while sudden, step-like changes suggest sudden damage, such as a seal ring breakage. When friction torque suddenly increases by more than 30% of its initial value or exhibits periodic fluctuations, it often indicates faults such as end face spalling, thermal cracking, or particle intrusion.

[0004] Commonly used methods for measuring mechanical seal friction torque include the support reaction force method and the transfer method. The support reaction force method measures torque based on the support reaction force generated by the mechanical seal under the action of end face friction torque. This method uses the reaction force on the fixed component to measure the reaction force generated by friction by installing a force sensor, and then calculates the friction torque. The transfer method measures torque based on the changes in physical parameters generated by the elastic element when transmitting torque. A high-precision torque sensor is installed on the rotating shaft to directly measure the friction torque generated by the mechanical seal.

[0005] However, in actual applications, the above measurement methods have many problems: (1) Due to the limited installation space inside the mechanical seal structure and the poor compatibility between the sensor and the mechanical seal structure, the relevant sensors are difficult to install and maintain, and it is also difficult to calibrate and calibrate after assembly; (2) Mechanical seals are often in rotating, vibrating, high-temperature and high-pressure working conditions, and even in corrosive fluid environments. Under the influence of environmental factors, the relevant sensors are difficult to achieve stable signal transmission; (3) Affected by assembly, calibration and environmental factors, the accuracy and stability of the relevant sensors are poor, making it difficult to perform long-term stable, reliable and continuous real-time measurement, and the measurement results are unreliable; (4) The detection capability of the relevant sensors is limited. When the mechanical seal works at ultra-high speed conditions (such as linear speed > 30m / s or rotation speed > 10^4rpm), the frequency response range of the relevant sensors (usually < 5kHz) is difficult to capture microsecond-level torque transient fluctuations. In short, the existing monitoring methods are difficult to achieve stable and reliable real-time measurement of the end face friction torque of the mechanical seal. Summary of the Invention

[0006] This application aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of this application is to provide a mechanical seal end face friction torque monitoring device and abnormality monitoring method, which can solve many problems of the prior art friction torque measurement structure, such as limited installation space, matching difficulties, complex signal transmission, and difficult installation and calibration, and realize real-time monitoring of friction torque.

[0007] The present application proposes a mechanical seal end face friction torque monitoring device, which includes a sealing housing, a sleeve, a dynamic ring, a static ring, a torque-sensitive sleeve, a strain sensor and a signal transmission assembly; the sealing housing is formed with a through hole extending in the axial direction; the sleeve is sleeved on the outer periphery of the rotating shaft and passes through the through hole, so as to be suitable for rotating relative to the sealing housing with the rotating shaft; the dynamic ring and the static ring are sleeved on the outer periphery of the sleeve, and the axial end face of the dynamic ring abuts against the static ring to form an end face seal; wherein the static ring is circumferentially limitedly connected to the sealing housing, and the dynamic ring is circumferentially limitedly connected to the sleeve, and the dynamic ring is suitable for rotating relative to the static ring with the sleeve; the torque-sensitive sleeve is sleeved on the outer periphery of the sleeve and is located on the side of the sealing housing away from the static ring; the torque-sensitive sleeve is limitedly connected to the sleeve, so as to be suitable for rotating with the sleeve; the strain sensor is arranged on the torque-sensitive sleeve, so as to be suitable for monitoring the strain of the torque-sensitive sleeve; the signal transmission assembly is arranged on the outer periphery of the torque-sensitive sleeve and connected to the strain sensor, so as to be suitable for transmitting and receiving strain signals from the strain sensor.

[0008] According to the mechanical seal end face friction torque monitoring device of the present application, since the end face friction torque of the dynamic ring and the static ring can be transmitted to the torque-sensitive sleeve through the sleeve, the change of the end face friction torque can be known by monitoring the strain of the torque-sensitive sleeve. The present application has a simple structure and good adaptability. The sleeves of different shaft diameters can be installed with replaceable torque-sensitive sleeves; the installation and calibration methods are simple and efficient. The key components of the present application for monitoring the end face friction torque, namely the torque-sensitive sleeve, strain sensor and other structures are not easily affected by environmental factors such as high temperature, high pressure and medium, and can perform stable and accurate monitoring to obtain reliable monitoring results.

[0009] According to some embodiments of the present application, a signal transmission component includes a slip ring inner ring, a conductive ring, a slip ring outer ring and a strain acquisition board; the slip ring inner ring is arranged on the outer periphery of the torque-sensitive sleeve and is circumferentially limited and connected to the torque-sensitive sleeve; the conductive ring is arranged on the outer periphery of the slip ring inner ring and is suitable for rotating with the slip ring inner ring, and the conductive ring is connected to the strain sensor to transmit the strain signal; the slip ring outer ring is arranged on the outer periphery of the slip ring inner ring and is circumferentially limited and connected to the sealing shell; the inner periphery of the slip ring outer ring is provided with a brush in contact with the conductive ring, and when the slip ring inner ring rotates relative to the slip ring outer ring, the brush and the conductive ring are in sliding contact to transmit the strain signal; the strain acquisition board is arranged on the outer periphery of the slip ring outer ring and is connected to the brush to receive the strain signal.

[0010] According to some embodiments of the present application, the signal transmission component further includes a signal conditioning circuit, which is connected to the brush and the strain acquisition board.

[0011] According to some embodiments of the present application, a first fork is provided on the outer periphery of the torque-sensitive sleeve, and a first fork groove is provided on the inner periphery of the slip ring inner ring. The first fork cooperates with the first fork groove to be suitable for a circumferentially limited connection between the torque-sensitive sleeve and the slip ring inner ring.

[0012] According to some embodiments of the present application, the mechanical seal end face friction torque monitoring device further includes a bearing, which is arranged between the inner ring of the slip ring and the outer ring of the slip ring to accommodate relative rotation between the inner ring of the slip ring and the outer ring of the slip ring.

[0013] According to some embodiments of the present application, a mounting groove is formed on the outer periphery of the torque-sensitive sleeve, and the strain sensor is disposed in the mounting groove.

[0014] According to some embodiments of the present application, the mechanical seal end face friction torque monitoring device also includes an expansion sleeve inner sleeve and an expansion sleeve outer sleeve, the expansion sleeve outer sleeve is circumferentially limitedly connected to the slip ring inner ring; the expansion sleeve inner sleeve is engaged with the rotating shaft; and the expansion sleeve outer sleeve and the expansion sleeve inner sleeve are connected by expansion sleeve bolts.

[0015] According to some embodiments of the present application, a second fork groove is formed on an axial end surface of one side of the inner ring of the slip ring, and a second fork is formed on an axial side of the outer sleeve of the expansion sleeve. The second fork cooperates with the second fork groove to be suitable for a circumferential limiting connection between the outer sleeve of the expansion sleeve and the inner ring of the slip ring.

[0016] According to some embodiments of the present application, a spring extending in the axial direction is provided between the stationary ring and the sealing housing.

[0017] The present application also proposes a method for monitoring abnormalities of the friction torque of a mechanical seal end face, using the above-mentioned mechanical seal end face friction torque monitoring device. The abnormality monitoring method includes the following steps:

[0018] Collect strain signals through strain sensors;

[0019] Establish a sample set of strain signals under normal working conditions;

[0020] Use the sample set to train the SVDD model;

[0021] A fuzzy membership degree is introduced for each strain signal in the sample set to establish a fuzzy sample set;

[0022] The SVDD model is optimized using the fuzzy sample set to generate the FSVDD model;

[0023] The strain signal to be measured by the strain sensor in real time is input into the FSVDD model for abnormality identification.

[0024] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0026] Figure 1 is a structural cross-sectional view of an end surface friction torque monitoring device according to some embodiments of the present application;

[0027] Figure 2 is a schematic structural diagram of a torque-sensitive sleeve according to some embodiments of the present application;

[0028] Figure 3 is a schematic structural diagram of the inner ring of the slip ring according to some embodiments of the present application;

[0029] Figure 4 2 is a schematic structural diagram of an inner expansion sleeve and an outer expansion sleeve according to some embodiments of the present application;

[0030] Figure 5It is a flow chart of a method for monitoring abnormal end face friction torque according to some embodiments of the present application.

[0031] Reference numerals:

[0032] Sealing housing 1; shaft sleeve 2; dynamic ring seat 3; dynamic ring 4; static ring 5; shaft end seal 6; dynamic ring auxiliary seal 7; static ring auxiliary seal 8; spring 9;

[0033] Torque-sensitive sleeve 10; mounting slot 101; wire hole 102; fastening hole 103; first shift fork 104;

[0034] Strain sensor 11; fastening bolt 12;

[0035] Slip ring inner ring 13; conductive groove 131; first shift fork groove 132; second shift fork groove 133; terminal 134;

[0036] Conductive ring 14; slip ring outer ring 15; brush 16; bearing 17; signal conditioning circuit 18; strain acquisition board 19; server 20;

[0037] An inner expansion sleeve 21 ; an outer expansion sleeve 22 ; a second shift fork 221 ; and an expansion screw 23 . DETAILED DESCRIPTION

[0038] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0039] Reference below Figures 1-4 A device for monitoring friction torque of a mechanical seal end face according to an embodiment of the present application is described.

[0040] The present application proposes a mechanical seal end face friction torque monitoring device, which includes a sealing housing 1, a sleeve 2, a dynamic ring 4, a static ring 5, a torque sensitive sleeve 10, a strain sensor 11 and a signal transmission component; the sealing housing 1 is formed with a through hole extending in the axial direction; the sleeve 2 is sleeved on the outer periphery of the rotating shaft and passes through the through hole, so as to be suitable for rotating relative to the sealing housing 1 with the rotating shaft; the dynamic ring 4 and the static ring 5 are sleeved on the outer periphery of the sleeve 2, and the dynamic ring 4 abuts against the axial end face of the static ring 5 to form an end face seal; wherein, the static ring 5 is circumferentially limited to the sealing housing 1 The dynamic ring 4 is connected with the sleeve 2 in a circumferential limiting manner, and the dynamic ring 4 is suitable for rotating with the sleeve 2 relative to the static ring 5; the torque-sensitive sleeve 10 is sleeved on the outer periphery of the sleeve 2 and is located on the side of the sealing housing 1 away from the static ring 5; the torque-sensitive sleeve 10 is connected with the sleeve 2 in a limiting manner to be suitable for rotating with the sleeve 2; the strain sensor 11 is provided on the torque-sensitive sleeve 10 to be suitable for monitoring the strain of the torque-sensitive sleeve 10; the signal transmission component is provided on the outer periphery of the torque-sensitive sleeve 10 and is connected with the strain sensor 11 to be suitable for transmitting and receiving the strain signal of the strain sensor 11.

[0041] According to the mechanical seal end face friction torque monitoring device of the present application, the sealing housing 1 defines a mechanical seal chamber and the outside of the mechanical seal, the dynamic ring 4 and the static ring 5 are arranged in the mechanical seal chamber, and the torque-sensitive sleeve 10, the strain sensor 11 and the signal transmission assembly are arranged on the outside of the mechanical seal. The rotating shaft refers to the transmission component in a mechanical seal device such as a pump or hydraulic transmission. When the device is in operation, the sealing housing 1 remains stationary, and the sleeve 2 rotates with the rotating shaft, driving the dynamic ring 4 to rotate synchronously, and at the same time driving the torque-sensitive sleeve 10 to rotate synchronously. Due to the relative rotation of the dynamic ring 4 and the static ring 5, the rotational friction on the sealing end face generates end face friction torque. The end face friction torque is transmitted from the dynamic ring 4 to the sleeve 2 and further to the torque-sensitive sleeve 10. The torque-sensitive sleeve 10 generates strain under the action of torque. The strain sensor 11 can detect the strain of the torque-sensitive sleeve 10 and generate a strain signal. The signal transmission assembly transmits the strain signal of the strain sensor 11 to the external system.

[0042] When assembling the mechanical seal end face friction torque monitoring device of the present application, first connect the dynamic ring 4 and the sleeve 2, connect the static ring 5 and the sealing housing 1, and then assemble the sleeve 2 with the dynamic ring 4 and the sealing housing 1 to complete the assembly process of the mechanical seal part; then, assemble the torque-sensitive sleeve 10 directly onto the sleeve 2, and this process does not require any changes to the internal structure of the mechanical seal.

[0043] The torque-sensitive sleeve 10 of the present application is sleeved on the outer periphery of the sleeve 2 and is connected in a limited position. It is removable and replaceable, which can reduce manufacturing costs; and it can be designed and processed to match the different outer diameters of the sleeve 2 to adapt to various shaft diameters. At the same time, the torque-sensitive sleeve 10, the strain sensor 11, and the signal transmission component are arranged on the outside of the mechanical seal. While facilitating installation and maintenance, it can effectively isolate high-temperature and high-pressure media, reduce the impact of the mechanical seal environment on strain detection and signal transmission, and improve the stability and safety of the monitoring device. In addition, the mechanical seal end face friction torque monitoring device of the present application can be zero-point calibrated by no-load operation, and the operation method is simple and efficient.

[0044] According to the mechanical seal end face friction torque monitoring device of the present application, since the end face friction torque of the dynamic ring 4 and the static ring 5 can be transmitted to the torque-sensitive sleeve 10 through the sleeve 2, the change of the end face friction torque can be known by monitoring the strain of the torque-sensitive sleeve 10. The present application has a simple structure and good adaptability. The sleeves 2 of different shaft diameters can be installed with the replaceable torque-sensitive sleeve 10; the installation and calibration methods are simple and efficient. The key components of the present application for monitoring the end face friction torque, namely the torque-sensitive sleeve 10, the strain sensor 11 and other structures are not easily affected by environmental factors such as high temperature, high pressure and medium, and can perform stable and accurate monitoring to obtain reliable monitoring results.

[0045] In some embodiments, a dynamic ring seat 3 is provided on the outer periphery of the sleeve 2, which is circumferentially connected to the sleeve 2, and the dynamic ring 4 is provided on the dynamic ring seat 3. Furthermore, four blind holes are formed on the connecting end surfaces of the dynamic ring 4 and the dynamic ring seat 3, and the circumferential connection between the dynamic ring 4 and the dynamic ring seat 3 is achieved by an anti-rotation pin.

[0046] In some embodiments, a shaft end seal 6 is provided between the shaft sleeve 2 and the rotating shaft, a dynamic ring auxiliary seal 7 is provided between the outer periphery of the dynamic ring 4 and the dynamic ring seat 3, and a static ring auxiliary seal 8 is provided between the outer periphery of the static ring 5 and the seal housing 1. This embodiment can improve the sealing effect of the mechanical seal device.

[0047] In some embodiments, the torque sensitive sleeve 10 is fixed to the outer periphery of the sleeve 2 by fastening bolts 12 and is circumferentially limited with the sleeve 2. Figure 2 As shown, the torque-sensitive sleeve 10 is formed with a radially extending fastening hole 103 .

[0048] According to some embodiments of the present application, the signal transmission component includes a slip ring inner ring 13, a conductive ring 14, a slip ring outer ring 15 and a strain acquisition board 19; the slip ring inner ring 13 is arranged on the outer periphery of the torque-sensitive sleeve 10 and is circumferentially limitedly connected to the torque-sensitive sleeve 10; the conductive ring 14 is arranged on the outer periphery of the slip ring inner ring 13 and is suitable for rotating with the slip ring inner ring 13, and the conductive ring 14 is connected to the strain sensor 11 to transmit the strain signal; the slip ring outer ring 15 is arranged on the outer periphery of the slip ring inner ring 13 and is circumferentially limitedly connected to the sealing housing 1; the inner periphery of the slip ring outer ring 15 is provided with a brush 16 in contact with the conductive ring 14, and when the slip ring inner ring 13 rotates relative to the slip ring outer ring 15, the brush 16 slides in contact with the conductive ring 14 to transmit the strain signal; the strain acquisition board 19 is arranged on the outer periphery of the slip ring outer ring 15 and is connected to the brush 16 to receive the strain signal.

[0049] In this embodiment, if Figure 1 As shown, the inner slip ring 13 rotates with the torque-sensitive sleeve 10, and the conductive ring 14 rotates with the inner slip ring 13. The outer slip ring 15 remains stationary with the sealed housing 1. Therefore, when the rotating shaft rotates, the sleeve 2, the torque-sensitive sleeve 10, and the inner slip ring 13 drive the conductive ring 14 to rotate. The conductive ring 14 and the brush 16 provided on the outer slip ring 15 rotate relative to each other, and sliding contact realizes signal transmission. This embodiment uses a combination of brushes 16 and conductive rings 14 to transmit strain signals. The contact between brushes 16 and conductive rings 14 is stable, and the signal transmission is highly reliable. It can cope with harsh monitoring environments such as high temperature, high pressure, and vibration, and can achieve stable, continuous, and efficient transmission of real-time monitoring signals.

[0050] According to some embodiments of the present application, the signal transmission component further includes a signal conditioning circuit 18, which is connected to the brush 16 and the strain acquisition board 19. In this embodiment, Figure 1 As shown, by setting up the signal conditioning circuit 18, the initial strain signal collected by the strain sensor 11 can be preprocessed, and the strain signal can be amplified, filtered, linearized, converted, etc., thereby reducing noise and interference in the strain signal, improving the clarity and accuracy of the strain signal, and improving the quality of the transmission signal; it also helps in the subsequent collection, processing and analysis of the signal, helps to improve the stability and measurement accuracy of monitoring, and reduces errors caused by the characteristics of the strain sensor 11.

[0051] In some embodiments, the signal transmission component also includes a server 20, and the strain acquisition board 19 is connected to the server 20 to transmit the collected strain signal to the server 20. The server 20 can store the real-time monitoring data and further process and analyze it to determine the abnormality of the end face friction torque.

[0052] This application utilizes the torque-sensitive sleeve 10, strain sensor 11, and signal transmission assembly to enable real-time monitoring and data analysis of end-face friction torque. The complete transmission path for the strain signal is as follows: the strain sensor 11 on the torque-sensitive sleeve 10, the conductive ring 14, the brush 17, the signal conditioning circuit 18, the strain acquisition board 19, and the server 20, among other edge devices.

[0053] According to some embodiments of the present application, a first shift fork 104 is provided on the outer periphery of the torque-sensitive sleeve 10, and a first shift fork groove 132 is provided on the inner periphery of the slip ring inner ring 13. The first shift fork 104 cooperates with the first shift fork groove 132 to be suitable for the circumferential limiting connection between the torque-sensitive sleeve 10 and the slip ring inner ring 13. In this embodiment, Figure 2 、 3 As shown, the circumferential limiting connection between the torque-sensitive sleeve 10 and the slip ring inner ring 13 is achieved by the cooperation of the shift fork and the shift fork groove, ensuring the synchronous rotation of the slip ring inner ring 13 and the torque-sensitive sleeve 10 and optimizing the transmission path of the strain signal; the connection method is simple, easy to assemble, and highly reliable, which can ensure the stability and durability of the mechanical sealing device during long-term operation.

[0054] According to some embodiments of the present application, the mechanical seal end face friction torque monitoring device further includes a bearing 17, which is disposed between the slip ring inner ring 13 and the slip ring outer ring 15, so as to be suitable for relative rotation between the slip ring inner ring 13 and the slip ring outer ring 15. Figure 1 As shown, the slip ring inner ring 13 and the slip ring outer ring 15 are connected by the bearing 17, and the structure has a high radial bearing capacity, which helps to maintain stability during long-term operation; and the provision of the bearing 17 can form a certain installation space on both sides of the axial direction of the bearing 17, so that the conductive ring 14 and the brush 16 and other structures can be easily installed between the slip ring inner ring 13 and the slip ring outer ring 15.

[0055] According to some embodiments of the present application, a mounting groove 101 is formed on the outer periphery of the torque sensitive sleeve 10, and the strain sensor 11 is disposed in the mounting groove 101. Figure 2 As shown, the installation groove 101 is provided to facilitate fixing of the strain sensor 11, thereby ensuring the connection stability between the strain sensor 11 and the torque-sensitive sleeve 10 during operation of the mechanical sealing device, thereby ensuring the accuracy and reliability of the end face friction torque measurement.

[0056] In some implementations, a conductive slot 131 is formed on the outer circumference of the inner slip ring 13, and the conductive ring 14 is installed in the conductive slot 131. Furthermore, the inner slip ring 3 is formed with an axially extending terminal 134, which is connected to the conductive ring 14; the torque-sensing sleeve 10 is formed with an axially extending wire hole 102, which is suitable for passing a wire connecting the strain sensor 11 and the terminal 134.

[0057] According to some embodiments of the present application, the mechanical seal end face friction torque monitoring device also includes an expansion sleeve inner sleeve 21 and an expansion sleeve outer sleeve 22, the expansion sleeve outer sleeve 22 is circumferentially limitedly connected to the slip ring inner ring 13; the expansion sleeve inner sleeve 21 is engaged with the rotating shaft; and the expansion sleeve outer sleeve 22 is connected to the expansion sleeve inner sleeve 21 through an expansion sleeve bolt 23.

[0058] In this embodiment, if Figure 4 As shown, an expansion sleeve inner sleeve 21 and an expansion sleeve outer sleeve 22 are provided. By tightening the expansion sleeve bolts 23, the expansion sleeve inner sleeve 21 radially expands, thereby securing it to the rotating shaft. After the end face friction torque is transmitted to the torque-sensitive sleeve 10, it is transferred to the expansion sleeve outer sleeve 22 via the slip ring inner ring 13. The expansion sleeve outer sleeve 22 further transmits the end face friction torque to the expansion sleeve inner sleeve 21 through its enveloping surface and the expansion sleeve bolts 23. Since the expansion sleeve inner sleeve 21 is connected to the rotating shaft, this embodiment ultimately achieves closed-loop transmission of the end face friction torque. Furthermore, the expansion sleeve inner sleeve 21 and the expansion sleeve outer sleeve 22 connect the rotating shaft to the sleeve 2, providing both positioning and transmission functions.

[0059] The above embodiment adopts a containerized design. By utilizing the cooperation of the expansion sleeve inner sleeve 21, the expansion sleeve outer sleeve 22, the bolts, the screws, the shift fork, and the shift fork groove, the overall installation and transmission of the mechanical seal end face friction torque monitoring device can be completed without disassembling the mechanical seal main structure, which greatly simplifies the installation process.

[0060] According to some embodiments of the present application, a second fork groove 133 is formed on an axial end surface of one side of the slip ring inner ring 13, and a second fork 221 is formed on an axial side of the expansion sleeve outer sleeve 22. The second fork 221 cooperates with the second fork groove 133 to be suitable for a circumferentially limited connection between the expansion sleeve outer sleeve 22 and the slip ring inner ring 13.

[0061] In this embodiment, if Figure 4 As shown, the circumferential limiting connection between the expansion sleeve inner sleeve 21 and the slip ring inner ring 13 is achieved by the cooperation of the shift fork and the shift fork groove. The connection method is simple and reliable, and can ensure the reliability and stability of the end face friction torque transmission.

[0062] According to some embodiments of the present application, a spring 9 extending in the axial direction is provided between the stationary ring 5 and the sealing housing 1. Figure 1 As shown, by providing the spring 9, the axial displacement of the stationary ring 5 can be compensated to ensure that the sealing end face fits tightly.

[0063] The present application also proposes a method for monitoring abnormalities of the friction torque of a mechanical seal end face, using the above-mentioned mechanical seal end face friction torque monitoring device. The abnormality monitoring method includes the following steps:

[0064] S1, collecting strain signals through the strain sensor 11;

[0065] S2. Establish a sample set of strain signals under normal working conditions; use the sample set to train an SVDD model (Support Vector Data Description, SVDD);

[0066] S3. Introduce a fuzzy membership degree for each strain signal in the sample set to establish a fuzzy sample set; use the fuzzy sample set to optimize the SVDD model to generate an FSVDD model (Fuzzy Support Vector Data Description: FSVDD);

[0067] S4. Input the strain signal to be measured, which is measured in real time by the strain sensor 11, into the FSVDD model for abnormality identification.

[0068] According to the abnormal monitoring method of end face friction torque of the present application, in step S2, the SVDD algorithm is a single classification algorithm, and its optimization goal is to display the training data in a high-dimensional space by mapping, and then iterate the multidimensional sphere with the smallest volume in the high-dimensional space. The multidimensional sphere covers as much training data as possible, and the data outside the multidimensional sphere is another cluster.

[0069] The algorithm formula of SVDD is as follows:

[0070] Set the training sample to x i ={x1,x2,L,x i}, in this sample set, i is the number of samples; this sample set defines a multidimensional sphere that contains almost all target class samples.

[0071] Introducing relaxation factor ξ i , improve the robustness of the algorithm to the training samples. At this time, the SVDD optimization problem is described as:

[0072]

[0073] Where a is the center of the multidimensional sphere, r is the radius of the multidimensional sphere, and C is the penalty coefficient (C>0), which is used to balance the number of abnormal training samples (number of samples outside the sphere) and the size of the multidimensional sphere.

[0074] In order to solve the above optimization problem, the following Lagrange equation is constructed:

[0075]

[0076] Where: α i , γ i is the Lagrange multiplication operator, all of which are non-negative;

[0077] Let r, a, ξ i The partial derivative is 0, so we get:

[0078]

[0079] When the sample points are inside the multidimensional sphere, α i =0; when the sample points are on the boundary of the multidimensional sphere, then 0<α i <C; when the sample points are outside the multidimensional sphere, then α i = C. The samples on the multidimensional sphere interface and within the boundary are called support vectors.

[0080] Substituting formula (1) into formula (3) we can get the optimization function:

[0081]

[0082] In the formula, K(x i ,x j ) is the Gaussian kernel function, which is expressed as follows:

[0083]

[0084] In high-dimensional space, the radius r of the multidimensional sphere can be obtained by the support vector (x sv ) to the center of the multidimensional sphere is calculated as:

[0085]

[0086] Where φ(x) is the nonlinear transformation function that maps data from the original space to the multidimensional spherical feature space;

[0087] For a single test sample z, its distance from the sphere center a can be expressed as:

[0088]

[0089] Then the monitoring coefficient of the new objective function z on the hypersphere boundary is:

[0090] ε=(dr) / r (8)

[0091] The above SVDD model simply identifies normal samples and faulty samples, but cannot accurately distinguish samples with different damage severity.

[0092] In this regard, according to the abnormal monitoring method of end face friction torque of the present application, in step S3, fuzzy mathematics theory is introduced into SVDD to generate FSVDD, which describes the development process from the initial defect to the final failure.

[0093] For each training sample xi Introducing a fuzzy membership s i , 0≤s i ≤1, it is considered important according to the severity of the damage. Fuzzy membership s i The larger the training sample x i The more important it is.

[0094] Suppose we are given a training set S of labeled training samples with fuzzy membership:

[0095] S={(x1,s1),(x2,s2),L(x n ,s n )} (9)

[0096] The fuzzy nonlinear vector function is redefined as:

[0097]

[0098] The kernel function is also rewritten as:

[0099]

[0100] Transform equations (4) to (7) into the following form:

[0101]

[0102] Where, is the fuzzy monitoring coefficient.

[0103] Furthermore, the collected strain signal is regarded as the equivalent shear strain ε. Given the outer diameter r of the torque sensitive sleeve 10, the elastic modulus E of the rotating shaft and the moment of inertia I of the section, the formula The friction torque M can be calculated T .

[0104] According to the abnormal monitoring method of end face friction torque of the present application, as Figure 5 As shown in FIG, when performing the abnormality detection process, in step S3, the extracted normal training samples are input into FSVDD for training to obtain a multidimensional sphere containing normal samples; in step S4, the strain signal sample to be measured in real time by the strain sensor 11 is input into the FSVDD model for abnormality recognition. When , the sample is a normal sample. The sample is an abnormal sample.

[0105] According to the abnormal monitoring method of end face friction torque of the present application, in view of the nonlinear time-varying characteristics of mechanical seal end face friction torque, an abnormal detection model of mechanical seal end face friction torque with improved support vector data description is constructed, and fuzzy logic and support vector data description are integrated to form a fuzzy support vector data description (FSVDD) abnormal detection method of mechanical seal end face friction torque. Unlike conventional SVDD that only uses positive samples to construct a hypersphere detection boundary, FSVDD innovatively establishes a dynamic weighted kernel function space, which significantly improves the abnormal detection sensitivity in scenarios where negative samples of industrial data are scarce. The present application uses FSVDD for abnormal detection of mechanical seal end face friction torque, makes real-time judgment on mechanical seal end face friction torque, and facilitates real-time prediction of uncontrollable faults of mechanical seal.

[0106] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0107] In the description of this application, "first feature" and "second feature" may include one or more such features.

[0108] In the description of this application, “plurality” means two or more.

[0109] In the description of the present application, a first feature being “on” or “under” a second feature may include the first and second features being in direct contact with each other, or the first and second features being in contact with each other not directly but via another feature therebetween.

[0110] In the description of this application, “above”, “above” and “on” a first feature of a second feature include the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0111] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative use of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0112] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A mechanical seal end face friction torque monitoring device, characterized in that: include: A sealing housing is formed with a through hole extending in the axial direction; a shaft sleeve, the shaft sleeve being sleeved on the outer periphery of the rotating shaft and passing through the through hole, so as to be adapted to rotate with the rotating shaft relative to the sealing housing; A dynamic ring and a static ring, the dynamic ring and the static ring being sleeved on the outer circumference of the shaft sleeve, the dynamic ring abutting against the axial end face of the static ring to form an end face seal; wherein the static ring is circumferentially limitedly connected to the sealing housing, the dynamic ring is circumferentially limitedly connected to the shaft sleeve, and the dynamic ring is adapted to rotate with the shaft sleeve relative to the static ring; a torque-sensitive sleeve, which is sleeved on the outer periphery of the sleeve and located on a side of the sealing housing away from the static ring; the torque-sensitive sleeve is limitedly connected to the sleeve and adapted to rotate with the sleeve; a strain sensor, the strain sensor being disposed on the torque-sensitive sleeve and being suitable for monitoring the strain of the torque-sensitive sleeve; A signal transmission component is provided on the outer periphery of the torque-sensitive sleeve and is connected to the strain sensor so as to be suitable for transmitting and receiving the strain signal of the strain sensor.

2. The mechanical seal end face friction torque monitoring device according to claim 1, characterized in that: The signal transmission component includes: An inner slip ring, the inner slip ring being arranged on the outer periphery of the torque-sensitive sleeve and being circumferentially limitedly connected to the torque-sensitive sleeve; a conductive ring, the conductive ring being arranged on the outer circumference of the slip ring inner ring and being adapted to rotate with the slip ring inner ring, the conductive ring being connected to the strain sensor to transmit the strain signal; a slip ring outer ring, the slip ring outer ring being arranged on the outer circumference of the slip ring inner ring and being circumferentially limitedly connected to the sealing housing; a brush in contact with the conductive ring is arranged on the inner circumference of the slip ring outer ring, and when the slip ring inner ring rotates relative to the slip ring outer ring, the brush and the conductive ring are in sliding contact to transmit the strain signal; A strain acquisition board is provided on the outer periphery of the slip ring outer ring and is connected to the brush to receive the strain signal.

3. The mechanical seal end face friction torque monitoring device according to claim 2, characterized in that: The signal transmission component further includes: A signal conditioning circuit is connected to the brush and the strain acquisition board.

4. The mechanical seal end face friction torque monitoring device according to claim 2, characterized in that: A first shift fork is provided on the outer periphery of the torque-sensitive sleeve, and a first shift fork groove is provided on the inner periphery of the slip ring inner ring. The first shift fork cooperates with the first shift fork groove to be suitable for circumferentially limiting connection between the torque-sensitive sleeve and the slip ring inner ring.

5. The mechanical seal end face friction torque monitoring device according to claim 2, characterized in that: Also includes: The bearing is arranged between the inner ring of the slip ring and the outer ring of the slip ring, so as to be suitable for the inner ring of the slip ring and the outer ring of the slip ring to rotate relative to each other.

6. The mechanical seal end face friction torque monitoring device according to claim 1, characterized in that: A mounting groove is formed on the outer periphery of the torque sensitive sleeve, and the strain sensor is arranged in the mounting groove.

7. The mechanical seal end face friction torque monitoring device according to claim 2, characterized in that: Also includes: An expansion sleeve inner sleeve and an expansion sleeve outer sleeve, wherein the expansion sleeve outer sleeve is circumferentially limitedly connected to the slip ring inner ring; the expansion sleeve inner sleeve is engaged with the rotating shaft; and the expansion sleeve outer sleeve and the expansion sleeve inner sleeve are connected by expansion sleeve bolts.

8. The mechanical seal end face friction torque monitoring device according to claim 7, characterized in that: A second fork groove is formed on one axial end surface of the slip ring inner ring, and a second fork is formed on one axial side of the expansion sleeve outer ring. The second fork cooperates with the second fork groove to be suitable for the circumferential limiting connection between the expansion sleeve outer ring and the slip ring inner ring.

9. The mechanical seal end face friction torque monitoring device according to claim 1, characterized in that: A spring extending in the axial direction is provided between the stationary ring and the sealing housing.

10. A method for monitoring abnormality of friction torque of a mechanical seal end face, characterized in that: Using the mechanical seal end face friction torque monitoring device according to any one of claims 1 to 9, the abnormality monitoring method includes the following steps: collecting strain signals through the strain sensor; Establishing a sample set of the strain signal under normal working conditions; Training an SVDD model using the sample set; Introducing a fuzzy membership degree into each strain signal in the sample set to establish a fuzzy sample set; Optimizing the SVDD model using the fuzzy sample set to generate an FSVDD model; The strain signal to be measured measured in real time by the strain sensor is input into the FSVDD model for abnormality identification.

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