Split mechanical seal

Abstract

The present application relates to the technical field of mechanical seal, and particularly relates to a split mechanical seal, comprising a dynamic ring and a static ring, wherein at least one suction body is arranged on the end face of the static ring which is attached to the dynamic ring; a liquid film integrity monitoring module is used to determine whether the liquid film integrity of the mechanical seal is qualified based on the particle size distribution characteristic parameter of abrasion debris; a sealing pressure monitoring module is used to determine whether the sealing pressure of the attached end face is qualified based on the thermal vibration coupling matching index, and to optimize the current of the suction body; a friction state monitoring module is used to determine whether the friction state of the attached end face is qualified based on the spectrum broadening index of the friction acoustic emission signal of the attached end face, so as to optimize the current correction coefficient; and a sealing medium monitoring module is used to determine whether the sealing performance of the mechanical seal is qualified based on the change rate of the leakage amount of the sealing medium, so as to optimize the preset distribution characteristic parameter. The present application improves the sealing stability of the mechanical seal.

Description

Technical Field

[0001] This invention relates to the field of mechanical seal technology, and more particularly to a split mechanical seal. Background Technology

[0002] Split mechanical seals, as key components in the field of shaft sealing, are widely used in rotating machinery such as pumps, compressors, and reactors. They are particularly suitable for large shafts, equipment that cannot be disassembled as a whole, and scenarios requiring online maintenance. Their advantage of allowing installation and maintenance without disassembling the main equipment significantly reduces downtime maintenance costs and shortens maintenance cycles, solving the pain points of traditional integral mechanical seals, such as cumbersome disassembly and assembly and strong dependence on equipment structure. While current split mechanical seals on the market offer significant improvements in ease of disassembly and assembly, they still have shortcomings in sealing stability and self-adaptive control capabilities. Some products, due to unreasonable design of the split sealing structure, are prone to media leakage. The pressure at the contact end of the dynamic and static rings is difficult to control precisely, often leading to liquid film rupture and accelerated end-face wear due to excessive contact pressure, or excessively thick liquid film and decreased sealing performance due to insufficient pressure. Furthermore, existing products lack real-time monitoring and dynamic adjustment mechanisms for sealing conditions, relying heavily on manual experience to judge operating status. This makes it impossible to respond promptly to changes in sealing parameters caused by fluctuations in operating conditions, resulting in limited seal life and difficulty in meeting the industrial demands for high-precision, long-term stable operation.

[0003] Chinese Patent Application Publication No. CN114370507A discloses a mechanical seal that improves cooling and lubrication. The mechanical seal is an internal flow type, wherein the sliding portion formed by the axial contact of the stationary ring and the rotating ring is closer to the inner diameter side than the guide plate, and the leakage direction of the sealed fluid in the sliding portion is towards the inner diameter side. The root portion of the guide plate gradually tilts radially outward towards the inner cover side, so that the sealed fluid discharged from the supply port of the rotating shaft to the circulation space is discharged to the front end portion of the guide plate, and the front end portion of the guide plate gradually tilts radially inward towards the inner cover side, so that the sealed fluid is discharged to the sliding portion.

[0004] The existing technology still has the following problems: the core sealing parameters such as the fitting pressure of the existing split mechanical seal are mostly statically preset or rely on manual experience for adjustment. It is impossible to dynamically correct the mechanical seal in real time by linking the operating condition feedback information. It is difficult to avoid the liquid film damage and end face wear caused by the fluctuation of operating conditions. It cannot make up for the decline in sealing performance in time, ultimately resulting in insufficient sealing stability and limited service life. Summary of the Invention

[0005] To address this, the present invention provides a split mechanical seal to overcome the problems in the prior art where the core sealing parameters such as the fitting pressure of split mechanical seals are mostly statically preset or rely on manual experience for adjustment. This makes it impossible to dynamically correct the mechanical seal in real time by linking the operating condition feedback information, which makes it difficult to avoid problems such as liquid film damage and end face wear caused by operating condition fluctuations, and makes it impossible to compensate for the decline in sealing performance in a timely manner, ultimately resulting in poor sealing stability.

[0006] To achieve the above objectives, the present invention provides a split mechanical seal, comprising:

[0007] The rotating ring has multiple threads in the opposite direction on its surface and is fixedly sleeved on the rotating shaft;

[0008] A stationary ring is fitted to the end face of the rotating ring away from the equipment and is sleeved on the rotating shaft. The outer side wall of the stationary ring is sealed to the inner side wall of the equipment. At least one attracting body, which is an electromagnet, is provided on the end face of the stationary ring that is fitted to the rotating ring.

[0009] The data acquisition module includes a temperature sensor for acquiring the end face temperature of the mating end faces of the stationary ring and the moving ring, a vibration sensor for acquiring the radial vibration of the stationary ring, and an acoustic emission sensor for acquiring the acoustic signal generated by friction of the mating end faces.

[0010] The liquid film integrity monitoring module is used to determine whether the liquid film integrity of the mechanical seal is qualified based on the comparison results of the particle size distribution characterization parameters of the wear debris in the flushing collection liquid with preset distribution characterization parameters.

[0011] The bonding pressure monitoring module is used to determine whether the bonding pressure of the bonding end face is qualified based on the thermal vibration coupling matching index determined by the temperature rise rate and the vibration amplitude of the radial vibration of the bonding end face, and to set several current correction coefficients based on the unqualified conditions to optimize the current of the absorber.

[0012] The friction state monitoring module is used to determine whether the friction state of the mating end face is qualified based on the spectral broadening index of the friction acoustic emission signal of the mating end face, and to optimize the current correction coefficient based on the broadening deviation between the spectral broadening index and the preset broadening index.

[0013] A sealing medium monitoring module is used to determine whether the sealing performance of the mechanical seal is qualified based on the rate of change of the leakage of the sealing medium, so as to optimize the preset distribution characterization parameters.

[0014] Furthermore, the liquid film integrity monitoring module determines that the liquid film integrity of the mechanical seal is unqualified based on the comparison result of the particle size distribution characterization parameter of the wear debris being greater than the preset distribution characterization parameter.

[0015] Furthermore, the particle size distribution characterization parameters are determined based on the Euclidean distance sequence between the corresponding positions of the particle size distribution curve of the wear debris and the standard particle size distribution curve.

[0016] Furthermore, under the condition that the integrity of the liquid film is not up to standard, the bonding pressure monitoring module determines that the bonding pressure of the bonding end face is too high based on the comparison result that the thermal vibration coupling matching index is greater than or equal to the first preset matching index.

[0017] The bonding pressure monitoring module determines that the bonding pressure of the bonding end face is too low based on the comparison result that the thermal vibration coupling matching index is less than the first preset matching index and greater than or equal to the second preset matching index.

[0018] Wherein, the first preset matching index is greater than the second preset matching index.

[0019] Furthermore, the thermal vibration coupling matching index is determined based on the Pearson correlation coefficient of the vibration amplitude sequence and the temperature rise rate sequence, which are acquired synchronously with the time axis and sampling frequency of temperature acquisition.

[0020] Furthermore, when the bonding pressure on the bonding end face is too high, the bonding pressure monitoring module sets several current adjustment coefficients to reduce the current of the suction body based on the comparison result of the first index difference between the thermal vibration coupling matching index and the first preset matching index and the preset index difference.

[0021] When the bonding pressure at the bonding end face is too low, the bonding pressure monitoring module sets several current correction coefficients to increase the current of the absorber based on the comparison result of the second index difference between the thermal vibration coupling matching index and the second preset matching index and the preset index difference.

[0022] Furthermore, the friction state monitoring module determines that the friction state of the mating end face is unqualified based on the comparison result that the spectrum broadening index is greater than the preset broadening index.

[0023] Furthermore, when the friction state of the mating end face is unqualified, the friction state monitoring module sets several current optimization coefficients based on the comparison result of the broadening deviation between the spectrum broadening index and the preset broadening index and the preset broadening deviation, so as to reduce the current correction coefficient.

[0024] Furthermore, the sealing medium monitoring module determines that the mechanical seal's sealing performance is unqualified based on a comparison result where the rate of change of the leakage of the sealing medium is greater than a preset rate of change.

[0025] Furthermore, when the sealing performance of the mechanical seal is unqualified, the sealing medium monitoring module sets several parameter adjustment coefficients based on the difference between the change rate and the preset change rate, and the comparison result of the difference between the change rate and the preset change rate, in order to reduce the preset distribution characterization parameter.

[0026] Compared with existing technologies, the advantages of this invention are that it significantly improves the basic sealing reliability of split mechanical seals through the synergistic design of the reverse-rotating multi-threaded structure of the rotating ring and the electromagnet attractor. The reverse-rotating multi-threaded structure on the rotating ring surface generates a reverse flow-blocking effect during rotation, effectively preventing leakage of the sealing medium to the outside and forming a multi-stage sealing barrier, adapting to the fluid barrier mechanism of mechanical seals. Simultaneously, the electromagnet attractor on the stationary ring end face can precisely control the contact pressure between the rotating and stationary rings. Combined with the sealing structure of the through-sleeve, locking ring, and fluororubber sealing ring, this not only solves the sealing shortcomings caused by uneven contact in split structures but also blocks the leakage path between the split surface and the end face through the multi-sealing layer design, ensuring that the friction pads of the rotating and stationary rings always maintain a stable contact state, providing structural protection for the formation and maintenance of the liquid film, thereby improving the sealing stability of the mechanical seal.

[0027] Furthermore, when the liquid film is intact, the dynamic and static rings are primarily lubricated by fluid, and the wear debris is mostly composed of small-diameter micro-protrusions from shear wear. However, when the liquid film is damaged, abrasive wear and adhesive wear occur, generating a large amount of large-diameter wear debris. This invention, by constructing a particle size distribution curve and calculating the coefficient of variation of the Euclidean distance sequence, can accurately capture the discrete changes in the particle size distribution of wear debris. It can determine liquid film abnormalities before the liquid film is completely ruptured and there is no irreversible damage to the end face, thus avoiding chain wear caused by liquid film failure and further improving the sealing stability of the mechanical seal.

[0028] Furthermore, this invention addresses the issue of excessively thin liquid films due to excessive bonding pressure, where temperature and vibration exhibit a strong linear positive correlation and the thermal-vibration coupling matching index approaches 1. By reducing the electromagnet current through a graded current adjustment coefficient, the degree of liquid film compression is alleviated. Conversely, when insufficient pressure results in excessively thick liquid films, temperature and vibration exhibit a periodic pulse correlation with an index in the moderate range. The module increases the current through a graded current correction coefficient, enhancing the end-face closing force. This avoids the problem of static preset pressure failing to adapt to fluctuations in operating conditions, ensuring the liquid film thickness remains stable within the optimal range, thereby further improving the sealing stability of the mechanical seal.

[0029] Furthermore, this invention captures material deformation and particle collision elastic waves generated by end-face friction using acoustic emission signals. When excessive current adjustment leads to sudden pressure changes, the spectral broadening index can quickly respond to changes in the dominant frequency and peak width. The original current correction coefficient is corrected through a graded current optimization coefficient, preventing accelerated wear on the end face due to continuous rigid contact or frequent impacts. This effectively avoids secondary failures that may be caused by single pressure control, thereby further improving the sealing stability of the mechanical seal. Attached Figure Description

[0030] Figure 1 This is a cross-sectional view of a split mechanical seal according to an embodiment of the present invention;

[0031] Figure 2 This is an enlarged view of part A of the present invention;

[0032] Figure 3 This is a structural block diagram of a split mechanical seal according to an embodiment of the present invention;

[0033] Figure 4 This is a flowchart for determining whether the liquid film integrity of a mechanical seal is qualified according to an embodiment of the present invention;

[0034] In the diagram: 1. Stationary ring, 2. Rotary ring, 3. Stationary ring friction pad, 4. Rotary ring friction pad, 5. Suction body, 6. First sealing ring, 7. Second sealing ring, 8. Third sealing ring, 9. Through sleeve, 10. Locking ring, 11. Rotating shaft, 12. Equipment housing, 13. Automatic flushing module, 14. Bolt, 15. Temperature sensor, 16. Acoustic emission sensor, 17. Vibration sensor. Detailed Implementation

[0035] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0036] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0037] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0038] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] Please see Figures 1-3 As shown, Figure 1 This is a cross-sectional view of a split mechanical seal according to an embodiment of the present invention; Figure 2 This is an enlarged view of part A of the present invention; Figure 3 This is a structural block diagram of a split mechanical seal according to an embodiment of the present invention.

[0040] The present invention provides a split mechanical seal comprising:

[0041] The rotating ring 2 has a multi-threaded anti-rotation surface and is fixedly sleeved on the rotating shaft 11;

[0042] A stationary ring 1 is fitted to the end face of the rotating ring 2 away from the device and is sleeved on the rotating shaft 11. The outer side wall of the stationary ring 1 is sealed to the inner side wall of the device. At least one attracting body 5 is provided on the end face of the stationary ring 1 that is fitted to the rotating ring 2. The attracting body 5 is an electromagnet.

[0043] A through sleeve 9 is fitted onto the rotating shaft 11 on the inner side wall of the moving ring 2;

[0044] A locking ring 10 is disposed at the end of the stationary ring 1 away from the rotating ring 2, and the locking ring 10 is connected to the rotating shaft 11 by a bolt 14;

[0045] The outer wall of the stationary ring 1 is provided with a first groove, and a first sealing ring 6 is provided in the first groove. The first sealing ring 6 is interference-fitted with the inner wall of the equipment housing 12, and the stationary ring 1 is sleeved on the outer surface of the through sleeve 9.

[0046] The inner sidewall of the moving ring 2 is provided with a second groove and a third groove. A second sealing ring 7 is fixed in the second groove and a third sealing ring 8 is fixed in the third groove. The second sealing ring 7 and the third sealing ring 8 are respectively fixedly connected to the outer sidewall of the rotating shaft 11.

[0047] Automatic rinsing module 13 is used to rinse the mating end faces of the moving ring 2 and the stationary ring 1;

[0048] The data acquisition module includes a temperature sensor 15 for acquiring the end face temperature of the mating end face of the stationary ring 1 and the moving ring 2, a vibration sensor 17 for acquiring the radial vibration of the stationary ring 1, and an acoustic emission sensor 16 for acquiring the acoustic signal generated by friction of the mating end face.

[0049] The liquid film integrity monitoring module is used to determine whether the liquid film integrity of the mechanical seal is qualified based on the comparison result of the particle size distribution characterization parameter of the wear debris in the flushing collection liquid of the automatic flushing module 13 and the preset distribution characterization parameter.

[0050] The bonding pressure monitoring module is used to determine whether the bonding pressure of the bonding end face is qualified based on the thermal vibration coupling matching index determined by the temperature rise rate and the vibration amplitude of the radial vibration of the bonding end face, and to set several current correction coefficients based on the unqualified conditions to optimize the current of the suction body 5.

[0051] The friction state monitoring module is used to determine whether the friction state of the mating end face is qualified based on the spectral broadening index of the friction acoustic emission signal of the mating end face, and to optimize the current correction coefficient based on the broadening deviation between the spectral broadening index and the preset broadening index.

[0052] A sealing medium monitoring module is used to determine whether the sealing performance of the mechanical seal is qualified based on the rate of change of the leakage of the sealing medium, so as to optimize the preset distribution characterization parameters.

[0053] Specifically, the first sealing ring 6, the second sealing ring 7, and the third sealing ring 8 are all made of fluororubber; the moving ring friction pad 4 is made of silicon carbide, and the stationary ring friction pad 3 is made of impregnated graphite.

[0054] In implementation, the rotating ring 2 is mounted on the rotating shaft 11, and the stationary ring 1 is sealed on the equipment housing 12. The stationary ring 1 does not rotate, and the rotating ring 2 is fixedly sleeved on the rotating shaft 11. The rotating ring 2 rotates together with the rotating shaft 11 through the locking ring 10, thereby achieving a seal between the rotating shaft 11 and the rotating ring 2. The stationary ring end face where the stationary ring 1 and the rotating ring 2 are in contact is provided with a stationary ring friction pad 3, and the rotating ring end face where the rotating ring 2 and the stationary ring 1 are in contact is provided with a rotating ring friction pad 4. The rotating ring friction pad 4 and the stationary ring friction pad 3 are in contact through the suction body 5 on the end face of the stationary ring, thereby achieving a seal of the equipment. Moreover, the multi-spiral spiral structure on the outer side of the rotating ring 2 can generate a reverse flow blocking and throttling effect to a great extent, thereby achieving a multi-stage seal and better sealing performance.

[0055] Please see Figure 4 As shown, it is a flowchart for determining whether the liquid film integrity of the mechanical seal is qualified according to an embodiment of the present invention.

[0056] Specifically, the liquid film integrity monitoring module determines that the liquid film integrity of the mechanical seal is unqualified based on the comparison result that the particle size distribution characterization parameter of the wear debris is greater than the preset distribution characterization parameter;

[0057] The liquid film integrity monitoring module determines that the liquid film integrity of the mechanical seal is qualified based on the comparison result that the particle size distribution characterization parameter of the wear debris is less than or equal to the preset distribution characterization parameter.

[0058] Specifically, the liquid film integrity monitoring module constructs a particle size distribution curve based on the particle size detection data of the wear debris in the rinsing collection liquid. Using the same horizontal axis as the comparison benchmark between the particle size distribution curve and the standard particle size distribution curve, the Euclidean distance between corresponding positions of the two curves is calculated point by point to extract the Euclidean distance sequence. The coefficient of variation of the Euclidean distance sequence is determined as the particle size distribution characterization parameter. The horizontal axis of the particle size distribution curve is the particle size value, and the vertical axis is the wear debris percentage.

[0059] Specifically, the standard particle size distribution curve refers to the particle size distribution curve of the wear debris under normal and stable operating conditions of the mechanical seal of the same model as the embodiment of the present invention.

[0060] Specifically, the preset distribution characterization parameter is set to a value range of [10%, 20%], and preferably 15% in this embodiment of the invention.

[0061] Specifically, the wear state of a mechanical seal is determined by the integrity of the liquid film. Differences in wear mechanisms under different liquid film conditions are directly reflected in the particle size distribution of the wear debris. When the liquid film is intact, fluid lubrication dominates on the dynamic and stationary ring faces, and wear is primarily micro-protrusion shear wear. The generated wear debris consists mainly of small-diameter particles, with a very low proportion of large-diameter particles, and the particle size distribution curve is highly concentrated in the small-diameter range. When the liquid film thins, partially ruptures, or experiences dry friction, the wear transforms into abrasive wear, adhesive wear, or fatigue wear, generating a large number of large-diameter particles. The particle size distribution curve shifts towards the large-diameter range, and the dispersion of the distribution increases significantly. The core function of a mechanical seal is to achieve three main effects through the liquid film between the dynamic and stationary ring faces: sealing and isolation, lubrication and friction reduction, and cooling. The integrity of the liquid film directly determines whether the seal can operate stably. When the liquid film is intact and its thickness is stable, the dynamic and static rings are in a fluid lubrication state, the leakage is controllable, the friction coefficient is low, the end face temperature is stable, and the mechanical seal is in good operating condition. When the liquid film becomes thinner or ruptures locally, the dynamic and static rings switch to a mixed lubrication state, the micro-protrusions on the end face contact cause abrasive wear, the leakage fluctuates, the temperature rises, the wear debris particle size increases, and the mechanical seal is in an unqualified operating condition.

[0062] Specifically, under conditions where the liquid film integrity is unqualified, the bonding pressure monitoring module collects continuous temperature data of the bonding end face through temperature sensor 15, with a sampling frequency set to 10Hz-20Hz and a collection period of 10min-30min, to obtain a temperature time series. It also collects continuous amplitude data of the radial vibration of the stationary ring 1 through vibration sensor 17, synchronously matching the time axis of the temperature acquisition with the sampling frequency to obtain a vibration amplitude time series. After smoothing the temperature time series and the vibration amplitude time series using a moving average method, a temperature sequence and a vibration amplitude sequence are obtained. The temperature sequence is used to calculate the temperature change at adjacent time points in a unit time interval of 1 minute to obtain the temperature rise rate sequence. The vibration amplitude sequence is used to extract the vibration amplitude at corresponding time points in the vibration amplitude sequence at the same time interval to obtain the synchronized vibration amplitude sequence. The temperature rise rate sequence and the synchronized vibration amplitude sequence are normalized using the min-max normalization method to obtain the normalized temperature rise rate sequence and the normalized vibration amplitude sequence. The Pearson correlation coefficient of the normalized temperature rise rate sequence and the normalized vibration amplitude sequence is determined as the thermal vibration coupling matching index.

[0063] Specifically, the bonding pressure monitoring module determines that the bonding pressure on the bonding end face is too high based on the comparison result that the thermal vibration coupling matching index is greater than or equal to the first preset matching index;

[0064] The bonding pressure monitoring module determines that the bonding pressure of the bonding end face is too low based on the comparison result that the thermal vibration coupling matching index is less than the first preset matching index and greater than or equal to the second preset matching index.

[0065] The bonding pressure monitoring module determines that the bonding pressure of the bonding end face is qualified based on the comparison result that the thermal vibration coupling matching index is less than the second preset matching index.

[0066] Wherein, the first preset matching index is greater than the second preset matching index.

[0067] Specifically, the first preset matching index is set to a value range of [0.8, 0.9], and is preferably 0.85 in this embodiment of the invention. The second preset matching index is set to a value range of [0.6, 0.79], and is preferably 0.7 in this embodiment of the invention.

[0068] Specifically, when the contact pressure is too high, the closing force of the dynamic and static ring end faces exceeds the opening force of the liquid film, causing excessive compression of the liquid film. This results in continuous rigid contact between the micro-protrusions on the end faces, and the friction mode shifts from fluid lubrication to mixed lubrication / boundary lubrication. Frictional heat generation is stable and continuously accumulates without instantaneous fluctuations, leading to a smooth temperature rise on the end faces. Simultaneously, the continuous contact impact of the micro-protrusions causes a gradual increase in radial vibration amplitude without pulse-like fluctuations. This ensures that the rate of temperature rise and the increase in vibration amplitude are completely synchronized, with their time-series curves exhibiting highly consistent characteristics. For every unit increase in temperature, the vibration amplitude increases by a fixed proportion, with no phase difference or fluctuation deviation. Reflected in the Pearson correlation coefficient, this stable linear linkage causes the thermal-vibration coupling matching index to approach 1. Therefore, a first preset matching index is set as the threshold for determining excessive pressure. When the thermal-vibration coupling matching index is greater than or equal to the first preset matching index, the contact pressure can be determined to be excessive. When the bonding pressure is too low, the closing force of the dynamic and static ring end faces is insufficient, the liquid film thickness exceeds the standard, the liquid film load-bearing capacity decreases, and intermittent separation and slapping phenomena occur at the end faces. The slapping generates instantaneous impact heat and impact vibration. During the separation phase, the temperature drops and the vibration amplitude decreases. This results in a sawtooth-shaped pulse fluctuation in the temperature curve and a synchronous pulse peak fluctuation in the vibration curve. The linkage between the two is periodic, but its stability is weaker than under excessive pressure conditions. The pulse peaks and troughs of temperature and vibration correspond one-to-one, showing a clear correlation. However, due to the existence of the separation phase, the linear fit between the two is lower than under excessive pressure conditions, and the rate of temperature rise and the ratio of vibration amplitude growth exhibit periodic fluctuations. Reflected in the Pearson correlation coefficient, this will cause the thermal-vibration coupling matching index to be in the middle range. Therefore, when the thermal-vibration coupling matching index is between the first and second preset matching indices, it can be determined that the bonding pressure is too low. When the bonding pressure is within the optimal range, the liquid film thickness is stable, the end faces of the moving and stationary rings are in a state of pure fluid lubrication, frictional heat is minimal and uniformly dissipated, the temperature shows no obvious upward trend, the fluctuation amplitude is small, and radial vibration is mainly due to medium turbulence disturbance, with a very small amplitude and no correlation with temperature changes. The correlation between the temperature rise rate and the vibration amplitude is extremely weak, and the time-series curves of the two show no obvious correlation, with a small Pearson correlation coefficient.

[0069] Specifically, when the bonding pressure on the bonding end face is too high, the bonding pressure monitoring module sets several current adjustment coefficients to reduce the current of the suction body 5 based on the comparison result of the first index difference between the thermal vibration coupling matching index and the first preset matching index and the preset index difference.

[0070] When the bonding pressure at the bonding end face is too low, the bonding pressure monitoring module sets several current correction coefficients to increase the current of the suction body 5 based on the comparison result of the second index difference between the thermal vibration coupling matching index and the second preset matching index and the preset index difference.

[0071] Specifically, the bonding pressure monitoring module determines to reduce the current of the suction body 5 by a first current adjustment coefficient based on the comparison result that the first index difference is greater than or equal to the preset index difference.

[0072] The bonding pressure monitoring module determines to reduce the current of the suction body 5 by using a second current adjustment coefficient based on the comparison result that the first index difference is less than the preset index difference.

[0073] Specifically, the bonding pressure monitoring module determines to increase the current of the suction body 5 by a first current correction coefficient based on the comparison result that the second index difference is greater than or equal to the preset index difference;

[0074] The bonding pressure monitoring module determines to increase the current of the suction body 5 by a second current correction coefficient based on the comparison result that the second index difference is less than the preset index difference.

[0075] Specifically, the preset index difference is set to a range of [0.1, 0.3], preferably 0.2 in this embodiment; the first current adjustment coefficient is set to a range of [0.8, 0.85], preferably 0.83 in this embodiment; the second current adjustment coefficient is set to a range of [0.86, 0.9], preferably 0.88 in this embodiment; the first current correction coefficient is set to a range of [1.2, 1.4], preferably 1.3 in this embodiment; and the second current correction coefficient is set to a range of [1.1, 1.19], preferably 1.15 in this embodiment.

[0076] Specifically, when adjusting the current of the attractor 5 using the current adjustment coefficient, the adjusted current value is the product of the corresponding current adjustment coefficient and the original current value of the attractor 5.

[0077] Specifically, the friction state monitoring module determines that the friction state of the mating end face is unqualified based on the comparison result that the spectral broadening index is greater than the preset broadening index;

[0078] The friction condition monitoring module determines that the friction condition of the mating end face is qualified based on the comparison result that the spectrum broadening index is less than or equal to the preset broadening index.

[0079] Specifically, the friction state monitoring module filters the original acoustic emission signal sequence collected by the acoustic emission sensor 16 using a bandpass filter to obtain an acoustic emission signal sequence; performs a fast Fourier transform on the acoustic emission signal sequence to obtain a frequency spectrum; determines the power spectrum based on the frequency spectrum to determine the dominant peak with the highest energy proportion in the frequency spectrum, and determines the peak energy and dominant frequency of the dominant peak; determines the two frequencies corresponding to the half-high energy of 0.5 times the peak energy on the power spectrum, determines the absolute difference between the two frequencies as the frequency spectrum peak width, and determines the ratio of the frequency spectrum peak width to the reference spectrum peak width as the spectrum broadening index.

[0080] Specifically, the filtering range is 10kHz-500kHz, and the reference peak width refers to the average value of 3-5 sets of frequency spectrum peak widths collected and calculated under the condition that the mechanical seal is in a qualified sealing state.

[0081] Specifically, the preset broadening index is set to a range of [1.5, 3], and this is preferred in embodiment 2 of the present invention.

[0082] Specifically, temperature and vibration parameters exhibit a lag in their response to friction conditions. When the pressure on the end face changes from too low to too high, the gradual increase in temperature and vibration amplitude requires a certain amount of time to accumulate. Acoustic emission signals, however, are elastic waves released during material deformation, microcrack propagation, and particle collisions during friction. They possess millisecond-level response speeds and can capture transient changes in the friction state instantly after adjustment. For example, if the current amplitude is too large during adjustment, causing the contact pressure to change directly from too low to too high, the micro-protrusions on the end face immediately enter a continuous contact state. The dominant frequency of the acoustic emission signal will rapidly increase from less than 100kHz to 100-300kHz, with a synchronous increase in the spectral broadening index. This allows for timely detection of over-adjustment before significant abnormalities in temperature and vibration occur.

[0083] Specifically, when the friction state of the mating end face is unqualified, the friction state monitoring module sets several current optimization coefficients based on the comparison result of the broadening deviation between the spectrum broadening index and the preset broadening index and the preset broadening deviation, so as to reduce the current correction coefficient.

[0084] Specifically, the friction state monitoring module determines to reduce the current correction coefficient by using a first current optimization coefficient based on the comparison result that the width deviation is greater than or equal to the preset width deviation;

[0085] Based on the comparison result that the widening deviation is less than the preset widening deviation, the friction state monitoring module determines to reduce the current correction coefficient by the second current optimization coefficient.

[0086] Specifically, the broadening deviation refers to the difference between the spectrum broadening index and the preset broadening index. The preset broadening deviation is set to a value range of [0.3, 0.8], preferably 0.5 in this embodiment of the invention. The first current optimization coefficient is set to a value range of [0.88, 0.92], preferably 0.9 in this embodiment of the invention. The second current optimization coefficient is set to a value range of [0.93, 0.96], preferably 0.94 in this embodiment of the invention.

[0087] Specifically, the method for adjusting the current correction coefficient using the current optimization coefficient is as follows: multiply the corresponding current optimization coefficient by the current correction coefficient, and the product is the optimized current correction coefficient.

[0088] Specifically, the sealing medium monitoring module determines that the mechanical seal's sealing performance is unqualified based on a comparison result where the rate of change of the leakage of the sealing medium is greater than a preset rate of change.

[0089] The sealing medium monitoring module determines that the mechanical seal's sealing performance is qualified based on a comparison result where the rate of change of the leakage of the sealing medium is less than or equal to the preset rate of change.

[0090] Specifically, the preset change rate is set to a range of [3%, 8%], and preferably 5% in this embodiment of the invention.

[0091] Specifically, the rate of change of leakage refers to the relative change in the volume of leaked sealing medium per unit time.

[0092] Specifically, the deterioration of sealing performance is a gradual process. In the initial stage of liquid film imbalance, the absolute value of leakage is still within the design acceptable range, but the rate of change of leakage has already increased. When the absolute value of leakage exceeds the standard, irreversible damage to the sealing surface has often occurred. Instantaneous fluctuations in operating conditions can cause a temporary increase in the absolute value of leakage, but such fluctuations are occasional, and the rate of change of leakage will quickly return to the acceptable range. However, the increase in leakage caused by the deterioration of sealing performance is continuous, and the rate of change will remain in the critical or unacceptable range for a long time. Using the rate of change of leakage to determine sealing performance can avoid misjudging instantaneous fluctuations in operating conditions as unacceptable sealing performance, thereby improving the reliability of monitoring and judgment.

[0093] Specifically, when the sealing performance of the mechanical seal is unqualified, the sealing medium monitoring module sets several parameter adjustment coefficients based on the difference between the change rate and the preset change rate, and the comparison result of the difference between the change rate and the preset change rate, in order to reduce the preset distribution characterization parameter.

[0094] Specifically, the sealing medium monitoring module determines to reduce the preset distribution characterization parameter by adjusting the first parameter coefficient based on the comparison result that the difference in the rate of change is greater than the preset difference in the rate of change.

[0095] The sealing medium monitoring module determines to reduce the preset distribution characterization parameter by adjusting the second parameter coefficient based on the comparison result that the difference in the rate of change is less than or equal to the preset difference in the rate of change.

[0096] Specifically, the preset range of the rate of change difference is set to [1%, 3%], preferably 2% in this embodiment of the invention; the range of the first parameter adjustment coefficient is set to [0.75, 0.85], preferably 0.8 in this embodiment of the invention; and the range of the second parameter adjustment coefficient is set to [0.86, 0.9], preferably 0.89 in this embodiment of the invention.

[0097] Specifically, the method of adjusting the preset distribution characterization parameter using the parameter adjustment coefficient is to multiply the corresponding parameter adjustment coefficient by the preset distribution characterization parameter, and the product is the adjusted preset distribution characterization parameter.

[0098] Specifically, when the sealing condition is substandard, it indicates that the liquid film has shown an irreversible deterioration trend. However, at this time, the dispersion of the wear debris particle size distribution may not have reached the original preset threshold, resulting in a lag in wear debris monitoring. Reducing the preset distribution characterization parameters can tighten the judgment threshold for wear debris monitoring, enabling it to capture minute changes in wear debris in the early stages of liquid film deterioration and trigger an early warning before the sealing performance deteriorates further, thus preventing the expansion of end-face damage.

[0099] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A split mechanical seal, characterized in that, include: The rotating ring has multiple threads in the opposite direction on its surface and is fixedly sleeved on the rotating shaft; A stationary ring is fitted to the end face of the rotating ring away from the equipment and is sleeved on the rotating shaft. The outer side wall of the stationary ring is sealed to the inner side wall of the equipment. At least one attracting body, which is an electromagnet, is provided on the end face of the stationary ring that is fitted to the rotating ring. The data acquisition module includes a temperature sensor for acquiring the end face temperature of the mating end faces of the stationary ring and the moving ring, a vibration sensor for acquiring the radial vibration of the stationary ring, and an acoustic emission sensor for acquiring the acoustic signal generated by friction of the mating end faces. The liquid film integrity monitoring module is used to determine whether the liquid film integrity of the mechanical seal is qualified based on the comparison result of the particle size distribution characterization parameters of the wear debris in the flushing collection liquid with preset distribution characterization parameters. The particle size distribution characterization parameters are determined based on the Euclidean distance sequence of the corresponding positions of the wear debris particle size distribution curve and the standard particle size distribution curve. The bonding pressure monitoring module is used to determine whether the bonding pressure of the bonding end face is qualified based on the thermal vibration coupling matching index determined by the temperature rise rate and the vibration amplitude of the radial vibration of the bonding end face, and to set several current correction coefficients based on the unqualified conditions to optimize the current of the absorber. The thermal vibration coupling matching index is determined based on the Pearson correlation coefficient of the vibration amplitude sequence and the temperature rise rate sequence that are synchronously acquired with the time axis and sampling frequency of temperature acquisition. A friction condition monitoring module is used to determine whether the friction condition of the mating end face is acceptable based on the spectral broadening index of the friction acoustic emission signal of the mating end face, and to optimize the current correction coefficient based on the broadening deviation between the spectral broadening index and a preset broadening index. The friction state monitoring module filters the original acoustic emission signal sequence collected by the acoustic emission sensor using a bandpass filter to obtain an acoustic emission signal sequence; it then performs a fast Fourier transform on the acoustic emission signal sequence to obtain a frequency spectrum; based on the frequency spectrum, it determines the power spectrum to identify the dominant peak with the highest energy proportion in the frequency spectrum, and determines the peak energy and dominant frequency of the dominant peak; it then determines the two frequencies corresponding to the half-high energy of 0.5 times the peak energy on the power spectrum, and determines the absolute difference between the two frequencies as the frequency spectrum peak width, and the ratio of the frequency spectrum peak width to the reference spectrum peak width as the spectrum broadening index; A sealing medium monitoring module is used to determine whether the sealing performance of the mechanical seal is qualified based on the rate of change of the leakage of the sealing medium, so as to optimize the preset distribution characterization parameters.

2. The split mechanical seal according to claim 1, characterized in that, The liquid film integrity monitoring module determines that the liquid film integrity of the mechanical seal is unqualified based on the comparison result that the particle size distribution characterization parameter of the wear debris is greater than the preset distribution characterization parameter.

3. The split mechanical seal according to claim 2, characterized in that, Under the condition that the integrity of the liquid film is not up to standard, the bonding pressure monitoring module determines that the bonding pressure of the bonding end face is too high based on the comparison result that the thermal vibration coupling matching index is greater than or equal to the first preset matching index. The bonding pressure monitoring module determines that the bonding pressure of the bonding end face is too low based on the comparison result that the thermal vibration coupling matching index is less than the first preset matching index and greater than or equal to the second preset matching index. Wherein, the first preset matching index is greater than the second preset matching index.

4. The split mechanical seal according to claim 3, characterized in that, When the bonding pressure on the bonding end face is too high, the bonding pressure monitoring module sets several current adjustment coefficients to reduce the current of the suction body based on the comparison result of the first index difference between the thermal vibration coupling matching index and the first preset matching index and the preset index difference. When the bonding pressure at the bonding end face is too low, the bonding pressure monitoring module sets several current correction coefficients to increase the current of the absorber based on the comparison result of the second index difference between the thermal vibration coupling matching index and the second preset matching index and the preset index difference.

5. The split mechanical seal according to claim 4, characterized in that, The friction condition monitoring module determines that the friction condition of the mating end face is unqualified based on the comparison result that the spectrum broadening index is greater than the preset broadening index.

6. The split mechanical seal according to claim 5, characterized in that, When the friction state of the mating end face is unqualified, the friction state monitoring module sets several current optimization coefficients based on the comparison results of the broadening deviation between the spectrum broadening index and the preset broadening index and the preset broadening deviation, so as to reduce the current correction coefficient.

7. The split mechanical seal according to claim 6, characterized in that, The sealing medium monitoring module determines that the mechanical seal's sealing performance is unqualified based on the comparison result that the rate of change of the leakage of the sealing medium is greater than the preset rate of change.

8. The split mechanical seal according to claim 7, characterized in that, When the sealing performance of the mechanical seal is unqualified, the sealing medium monitoring module sets several parameter adjustment coefficients based on the difference between the change rate and the preset change rate, and the comparison result of the difference between the change rate and the preset change rate, in order to reduce the preset distribution characterization parameter.

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