Split type mechanical seal

Abstract

The invention relates to the technical field of mechanical seals, in particular to a split type mechanical seal which comprises a movable ring and a static ring, and at least one suction body is arranged on the end face, attached to the movable ring, of the static ring. The liquid film integrity monitoring module is used for determining whether the liquid film integrity of the mechanical seal is qualified or not based on the particle size distribution characterization parameters of the abrasive dust; the fitting pressure monitoring module is used for judging whether the fitting pressure of the fitting end surface is qualified or not based on the thermal vibration coupling matching index and optimizing the current of the suction body; the friction state monitoring module is used for determining whether the friction state of the fitting end face is qualified or not based on the spectrum broadening index of the friction acoustic emission signal of the fitting end face so as to optimize the current correction coefficient; and the sealing medium monitoring module is used for determining whether the sealing performance of the mechanical seal is qualified or not based on the change rate of the leakage rate of the sealing medium so as to optimize the preset distribution characterization parameters. The sealing stability of the mechanical seal is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical seals, in particular to a split mechanical seal. BACKGROUND

[0002] As a key component in the field of rotating shaft sealing, split mechanical seal is widely used in rotating machinery equipment such as pumps, compressors, reaction kettles, etc., and is particularly suitable for large rotating shafts, equipment that cannot be disassembled as a whole, and online maintenance scenarios. With the advantage of being able to realize installation and maintenance without disassembling the main body of the equipment, it significantly reduces the maintenance cost of the equipment downtime and shortens the maintenance cycle, solving the pain points of traditional whole mechanical seal such as complicated disassembly and assembly and strong dependence on equipment structure. Although the split mechanical seals on the market have improved in terms of disassembly and assembly convenience, there are still deficiencies in sealing stability and self-adaptive control capability. Some products have design flaws in the sealing structure of the split surface, which can easily cause medium leakage. The pressure of the dynamic and static ring fitting end face is difficult to control accurately, and the liquid film is often broken due to excessive fitting pressure, causing end face wear to intensify, or the liquid film is too thick due to insufficient pressure, causing the sealing performance to decline. At the same time, the existing products lack real-time monitoring and dynamic adjustment mechanism for sealing working conditions, and rely mainly on manual experience to judge the running state, which cannot respond to changes in sealing parameters caused by working condition fluctuations in time, resulting in limited sealing life and difficulty in meeting the industrial demand for high-precision and long-period stable operation.

[0003] Chinese patent application publication No. CN114370507A discloses a mechanical seal element, the cooling and lubrication state of which is improved. The mechanical seal element is an inner flow type mechanical seal element, wherein a sliding portion formed by the mutual contact of a stationary ring and a rotating ring in the axial direction is closer to the inner diameter side than a guide plate, and the leakage direction of the sealed fluid in the sliding portion is the inner diameter side. The root portion of the guide plate gradually tilts toward the radial outer side as it approaches the side of the built-in cover, so that the sealed fluid that is guided from the supply port portion of the rotating shaft to the circulation space is guided to the front end portion of the guide plate. The front end portion of the guide plate gradually tilts toward the radial inner side as it approaches the side of the built-in cover, so that the sealed fluid is guided to the sliding portion.

[0004] There are still the following problems in the prior art: The core sealing parameters such as the fitting pressure of the existing split mechanical seal are mostly statically preset or adjusted relying on manual experience, which cannot be dynamically corrected in real time in response to the working condition feedback information of the mechanical seal, making it difficult to avoid the problems of liquid film damage and end face wear caused by working condition fluctuations, and unable to compensate for the decline in sealing performance in time, ultimately resulting in insufficient sealing stability and limited service life. SUMMARY

[0005] To this end, the present application provides a split mechanical seal to overcome the problem that the core sealing parameters such as the fitting pressure of the split mechanical seal in the prior art are mostly statically preset or adjusted depending on manual experience, cannot be dynamically corrected in real time in linkage with the working condition feedback information of the mechanical seal, are difficult to avoid the problems of liquid film damage and end face wear caused by working condition fluctuations, cannot timely compensate for the sealing performance decay, and finally lead to poor sealing stability.

[0006] To achieve the above-mentioned purpose, the present application provides a split mechanical seal, comprising: a rotating ring, the surface of which is provided with counter-rotational multi-thread, and the rotating ring is fixedly sleeved on the rotating shaft; a static ring, the end face of which is fitted with the rotating ring away from the equipment, and the static ring is sleeved on the rotating shaft, and the outer side wall of the static ring is sealingly connected with the inner side wall of the equipment, wherein at least one suction body is arranged on the end face of the static ring fitted with the rotating ring, and the suction body is an electromagnet; a data acquisition module, comprising a temperature sensor for acquiring the end face temperature of the fitted end face of the static ring and the rotating ring, a vibration sensor for acquiring the radial vibration of the static ring, and an acoustic emission sensor for acquiring the acoustic signal generated by the friction of the fitted end face; a liquid film integrity monitoring module for determining 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 abrasion debris in the flushing collection liquid with the preset distribution characterization parameter; a fitting pressure monitoring module for determining whether the fitting pressure of the fitted end face is qualified based on the thermal vibration coupling matching index determined based on the temperature rise rate of the fitted end face and the vibration amplitude of the radial vibration, and setting a plurality of current correction coefficients based on the unqualified condition to optimize the current of the suction body; a friction state monitoring module for determining whether the friction state of the fitted end face is qualified based on the frequency spectrum broadening index of the friction acoustic emission signal of the fitted end face, and optimizing the current correction coefficient based on the spread deviation of the frequency spectrum broadening index from the preset spread index; a sealing medium monitoring module for determining whether the sealing performance of the mechanical seal is qualified based on the change rate of the leakage amount of the sealing medium, and optimizing the preset distribution characterization parameter.

[0007] Further, 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 abrasion debris is greater than the preset distribution characterization parameter.

[0008] Further, the particle size distribution characterization parameter is determined based on the Euclidean distance sequence of the corresponding positions of the particle size distribution curve of the abrasion debris and the standard particle size distribution curve.

[0009] Further, the fitting pressure monitoring module determines that the fitting pressure of the fitting end face is too large based on a comparison result that the thermal-vibration coupling matching index is greater than or equal to a first preset matching index under the condition that the liquid film integrity is unqualified. The fitting pressure monitoring module determines that the fitting pressure of the fitting end face is too small based on a comparison result that the thermal-vibration coupling matching index is less than the first preset matching index and greater than or equal to a second preset matching index. The first preset matching index is greater than the second preset matching index.

[0010] Further, the thermal-vibration coupling matching index is determined based on a Pearson correlation coefficient of a vibration amplitude sequence and a temperature rise rate sequence collected synchronously with a time axis of temperature collection and a sampling frequency.

[0011] Further, the fitting pressure monitoring module sets a plurality of current adjustment coefficients to reduce the current of the suction body based on a comparison result of a first index difference between the thermal-vibration coupling matching index and the first preset matching index and a preset index difference under the condition that the fitting pressure of the fitting end face is too large. The fitting pressure monitoring module sets a plurality of current correction coefficients to increase the current of the suction body based on a comparison result of a second index difference between the thermal-vibration coupling matching index and the second preset matching index and a preset index difference under the condition that the fitting pressure of the fitting end face is too small.

[0012] Further, the friction state monitoring module determines that the friction state of the fitting end face is unqualified based on a comparison result that the frequency spectrum broadening index is greater than a preset broadening index.

[0013] Further, the friction state monitoring module sets a plurality of current optimization coefficients to reduce the current correction coefficient based on a comparison result of a broadening deviation between the frequency spectrum broadening index and the preset broadening index and a preset broadening deviation under the condition that the friction state of the fitting end face is unqualified.

[0014] Further, the sealing medium monitoring module determines that the sealing performance of the mechanical seal is unqualified based on a comparison result that a change rate of a leakage amount of the sealing medium is greater than a preset change rate.

[0015] Further, the sealing medium monitoring module sets a plurality of parameter adjustment coefficients to reduce the preset distribution representation parameter based on a comparison result of a change rate difference between the change rate and the preset change rate and a preset change rate difference under the condition that the sealing performance of the mechanical seal is unqualified.

[0016] Compared with the prior art, the beneficial effects of the present application are that the present application significantly improves the basic sealing reliability of the split mechanical seal through the cooperative design of the counter-rotational multi-thread structure of the dynamic ring and the electromagnetic attraction body. The counter-rotational multi-thread on the surface of the dynamic ring can produce a reverse resistance throttling effect during rotation, effectively preventing the leakage of the sealing medium to the outside, forming a multi-stage sealing barrier, and adapting to the fluid blocking mechanism of the mechanical seal; at the same time, the electromagnetic attraction body on the end surface of the static ring can accurately control the fitting pressure of the dynamic and static rings, and cooperate with the sealing structure of the through sleeve, locking ring and fluorine rubber sealing ring to not only solve the sealing short board caused by uneven fitting of the split structure, but also block the leakage path of the split surface and the end surface through the multi-sealing level design, so that the dynamic and static ring friction pad always maintains a stable fitting state, providing a structural guarantee for the formation and maintenance of the liquid film, thereby improving the sealing stability of the mechanical seal.

[0017] Further, when the liquid film is complete, the dynamic and static rings are mainly fluid lubricated, and the abrasive particles are mainly small particle size micro-convex shear wear products, while when the liquid film is damaged, abrasive wear and adhesive wear will occur, generating a large amount of large particle size abrasive particles. The present application can accurately capture the discrete changes of the abrasive particle size distribution by constructing the particle size distribution curve and calculating the Euclidean distance sequence variation coefficient, and can determine the abnormality of the liquid film before the liquid film is completely broken and the end surface is irreversibly damaged, thereby avoiding the chain wear caused by the failure of the liquid film, and further improving the sealing stability of the mechanical seal.

[0018] Further, when the fitting pressure is too large to cause the liquid film to be too thin, the temperature and vibration are strongly linearly positively correlated, the thermal vibration coupling matching index tends to 1, the electromagnetic current is reduced by the hierarchical current adjustment coefficient, and the compression degree of the liquid film is relieved; when the pressure is too small to cause the liquid film to be too thick, the temperature and vibration are periodically pulse correlated, the index is in the medium interval, and the current is increased by the hierarchical current correction coefficient to improve the end surface closing force. The problem that the static preset pressure cannot adapt to the working condition fluctuation is avoided, so that the liquid film thickness is always stable in the optimal interval, thereby further improving the sealing stability of the mechanical seal.

[0019] Further, the present application captures the material deformation and particle collision elastic wave generated by the end surface friction through the acoustic emission signal, and when the current adjustment is excessive to cause a sudden change in pressure, the frequency spectrum broadening index can quickly respond to the changes in the main frequency and the spectrum peak width, and the original current correction coefficient is corrected by the hierarchical current optimization coefficient to avoid the aggravation of wear caused by the continuous rigid contact or frequent beating of the end surface. The secondary failure that may be caused by single pressure regulation is effectively avoided, thereby further improving the sealing stability of the mechanical seal. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a sectional view of the split mechanical seal of the embodiment of the present application; Figure 2 It is an enlarged view of part A of the embodiment of the present application; Figure 3 Structure block diagram of the split mechanical seal of the embodiment of the present application; Figure 4 Flow chart for determining whether the liquid film integrity of the mechanical seal is qualified or not for the embodiment of the present application; In the figure: 1, static ring, 2, dynamic ring, 3, static ring friction pad, 4, dynamic 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 shell, 13, automatic flushing module, 14, bolt, 15, temperature sensor, 16, acoustic emission sensor, 17, vibration sensor. DETAILED DESCRIPTION

[0021] In order to make the objects and advantages of the present application clearer, the present application will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0022] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0023] It should be noted that in the description of the present application, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings, which is only for the convenience of description and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0024] In addition, it should also be noted that in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0025] Please refer to Figures 1-3 shown, Figure 1 Sectional view of the split mechanical seal of the embodiment of the present application; Figure 2 Enlarged view of part A of the embodiment of the present application; Figure 3 Structure block diagram of the split mechanical seal of the embodiment of the present application.

[0026] The split mechanical seal of the embodiment of the present application comprises: a dynamic ring 2, which is provided with reverse multi-threads on its surface and is fixedly sleeved on the rotating shaft 11; a static ring 1, which is attached to the end surface of the dynamic ring 2 away from the equipment, is sleeved on the rotating shaft 11, and the outer sidewall of the static ring 1 is sealingly connected with the inner sidewall of the equipment, wherein at least one suction body 5 is provided on the end surface of the static ring 1 attached to the dynamic ring 2, and the suction body 5 is an electromagnet; a through sleeve 9, which is sleeved on the rotating shaft 11 of the inner sidewall of the dynamic ring 2; a locking ring 10, which is provided at the end of the static ring 1 away from the dynamic ring 2, and the locking ring 10 is connected with the rotating shaft 11 through a bolt 14; the outer sidewall of the static ring 1 is provided with a first groove, and a first sealing ring 6 is arranged in the first groove, the first sealing ring 6 is interference-connected with the inner wall of the equipment shell 12, and the static ring 1 is sleeved on the outer surface of the through sleeve 9; the inner sidewall of the dynamic 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, and the second sealing ring 7 and the third sealing ring 8 are fixedly connected with the outer sidewall of the rotating shaft 11, respectively; an automatic flushing module 13, which is used to flush the attached end surface of the dynamic ring 2 and the static ring 1; a data acquisition module, which includes a temperature sensor 15 used to acquire the temperature of the attached end surface of the static ring 1 and the dynamic ring 2, a vibration sensor 17 used to acquire the radial vibration of the static ring 1, and an acoustic emission sensor 16 used to acquire the acoustic signal generated by the friction of the attached end surface; a liquid film integrity monitoring module, which 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 abrasion debris collected in the flushing of the automatic flushing module 13 and the preset distribution characterization parameter; a contact pressure monitoring module, which is used to determine whether the contact pressure of the attached end surface is qualified based on the thermal vibration coupling matching index determined based on the temperature rise rate and the vibration amplitude of the radial vibration of the attached end surface, and to set a plurality of current correction coefficients based on the unqualified condition to optimize the current of the suction body 5; a friction state monitoring module, which is used to determine whether the friction state of the attached end surface is qualified based on the frequency spectrum broadening index of the friction acoustic emission signal of the attached end surface, and to optimize the current correction coefficient based on the broadening deviation of the frequency spectrum broadening index and the preset broadening index; a sealing medium monitoring module, which 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, and to optimize the preset distribution characterization parameter.

[0027] Specifically, the first sealing ring 6, the second sealing ring 7 and the third sealing ring 8 are all fluororubber; the dynamic ring friction pad 4 is silicon carbide, and the static ring friction pad 3 is impregnated graphite.

[0028] In the implementation, the dynamic ring 2 is arranged on the rotating shaft 11, the static ring 1 is sealingly arranged on the equipment shell 12, the static ring 1 does not rotate, the dynamic ring 2 is fixedly sleeved on the rotating shaft 11, rotates together with the rotating shaft 11 through the locking ring 10, realizes the sealing between the rotating shaft 11 and the dynamic ring 2, the static ring end face of the static ring 1 abutting against the dynamic ring 2 is provided with the static ring friction pad 3, the dynamic ring end face of the dynamic ring 2 abutting against the static ring 1 is provided with the dynamic ring friction pad 4, and the dynamic ring friction pad 4 and the static ring friction pad 3 are abutted through the suction body 5 of the static ring end face, so that the sealing of the equipment is realized, and the dynamic ring 2 is provided with a plurality of helical thread structures on the outer side and in the same direction, which can greatly generate reverse resistance and exhaust throttling effects, so that multi-stage sealing is realized, and the sealing performance is better.

[0029] Please refer to Figure 4 As shown in the figure, it is a flow chart for determining whether the liquid film integrity of the mechanical seal is qualified according to the embodiment of the application.

[0030] 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 characteristic parameter of the abrasion debris is greater than the preset distribution characteristic parameter. 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 characteristic parameter of the abrasion debris is less than or equal to the preset distribution characteristic parameter.

[0031] Specifically, the liquid film integrity monitoring module constructs a particle size distribution curve based on the particle size detection data of the abrasion debris in the flushing collection liquid, takes the same horizontal coordinate as the comparison reference for the particle size distribution curve and a standard particle size distribution curve, point-by-point calculates the Euclidean distance of the corresponding positions of the two curves to extract a Euclidean distance sequence, and determines the coefficient of variation of the Euclidean distance sequence as the particle size distribution characteristic parameter, wherein the horizontal coordinate of the particle size distribution curve is the particle size value, and the vertical coordinate is the abrasion debris proportion.

[0032] Specifically, the standard particle size distribution curve refers to the abrasion debris particle size distribution curve of the mechanical seal of the same model as the embodiment of the application under normal and stable operating conditions.

[0033] Specifically, the preset distribution characteristic parameter is set to [10%, 20%], and the embodiment of the application preferably is 15%.

[0034] Specifically, the wear state of the mechanical seal is determined by the liquid film integrity. The difference in wear mechanism under different liquid film states will be directly reflected in the particle size distribution of the wear debris. When the liquid film is complete, the dynamic ring end face and the static ring end face are mainly lubricated by fluid, the wear is only micro-asperity shear wear, the generated wear debris is mainly small particle size particles, and the proportion of large particle size particles is very low, and the particle size distribution curve is highly concentrated in the small particle size interval. When the liquid film is thin, locally broken or dry friction, the wear turns into abrasive wear, adhesive wear or fatigue wear, which will generate a large number of large particle size particles, and the particle size distribution curve will shift to the large particle size interval, and the distribution dispersion will significantly increase. The core function of the mechanical seal is to realize the three functions of sealing isolation, lubrication and friction reduction, and cooling and temperature reduction through the liquid film between the dynamic and static ring end faces. The integrity of the liquid film directly determines whether the seal can operate stably. When the liquid film is complete and the thickness is stable, the dynamic and static rings are in a fluid lubrication state, the leakage is controllable, the friction coefficient is low, and the end face temperature is stable, and the mechanical seal operates in a good state. When the liquid film is locally thinned or broken, the dynamic and static rings turn into a mixed lubrication state, the micro-asperity contact of the end face triggers abrasive wear, the leakage fluctuates, the temperature rises, and the particle size of the wear debris increases, and the mechanical seal operates in an unqualified state.

[0035] Specifically, the fitting pressure monitoring module acquires continuous temperature data of the fitting end face through the temperature sensor 15 under the condition that the liquid film integrity is unqualified, the sampling frequency is set to 10-20 Hz, the acquisition period is 10-30 min, the temperature time sequence is obtained, the continuous amplitude data of the radial vibration of the static ring 1 is acquired through the vibration sensor 17, the time axis of temperature acquisition is matched with the sampling frequency, and the vibration amplitude time sequence is obtained. The temperature time sequence and the vibration amplitude time sequence are smoothed by the moving average method to obtain the temperature sequence and the vibration amplitude sequence. The temperature change amount of adjacent time is calculated by the temperature sequence at a unit time interval of 1 min to obtain the temperature rise rate sequence, and the vibration amplitude sequence is extracted according to the same time interval to obtain the synchronized vibration amplitude sequence. The min-max normalization method is used to normalize the temperature rise rate sequence and the synchronized vibration amplitude sequence 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.

[0036] Specifically, the fitting pressure monitoring module determines that the fitting pressure of the fitting end face is too large based on the comparison result that the thermal vibration coupling matching index is greater than or equal to the first preset matching index. The fitting pressure monitoring module determines that the fitting pressure of the fitting end face is too small 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. The fitting pressure monitoring module determines that the fitting pressure of the fitting end face is qualified based on a comparison result that the thermal-vibration coupling matching index is less than the second preset matching index. The first preset matching index is greater than the second preset matching index.

[0037] Specifically, the first preset matching index is set to [0.8, 0.9], and the second preset matching index is set to [0.6, 0.79].

[0038] Specifically, when the fitting pressure is too large, the closing force of the dynamic and static ring end face is greater than the liquid film opening force, the liquid film is excessively compressed, the end face microconvex body is in continuous rigid contact, and the friction mode is changed from fluid lubrication to mixed lubrication / boundary lubrication. The generation of friction heat is stable and continuously accumulates without transient fluctuations, which drives the end face temperature to smoothly rise; at the same time, the continuous contact impact of the microconvex body will cause the radial vibration amplitude to gradually increase without pulse fluctuations. The temperature rise rate and the vibration amplitude growth are completely synchronized, and the time sequence change curve forms of the two are highly consistent. For every unit increase in temperature, the vibration amplitude corresponds to a fixed proportion of unit increase without phase difference or fluctuation deviation. In terms of the Pearson correlation coefficient, this stable linear linkage relationship will make the thermal-vibration coupling matching index tend to 1, so the first preset matching index is set as the determination threshold for excessive pressure. When the thermal-vibration coupling matching index is greater than or equal to the first preset matching index, it is determined that the fitting pressure is too large. When the fitting pressure is too small, the closing force of the dynamic and static ring end face is insufficient, the liquid film thickness is excessive, the liquid film bearing capacity is reduced, and the end face appears intermittent separation and slapping phenomenon. The slapping instantaneously generates transient impact heat and impact vibration, and the temperature drops and the vibration amplitude decreases during the separation stage. The temperature curve presents a sawtooth-shaped pulse fluctuation, and the vibration curve presents a synchronous pulse peak fluctuation. The linkage of the two has periodicity, but the stability is weaker than that of the excessive pressure condition. The pulse peak and valley of the temperature and vibration correspond one by one, and have clear relevance. However, due to the existence of the separation stage, the linear fitting degree of the two is lower than that of the excessive pressure condition, and the temperature rise rate and the growth rate of the vibration amplitude have periodic fluctuations. In terms of the Pearson correlation coefficient, the thermal-vibration coupling matching index is in the middle interval, so when the thermal-vibration coupling matching index is between the first preset matching index and the second preset matching index, it is determined that the fitting pressure is too small. When the fitting pressure is in the optimal interval, the liquid film thickness is stable, the dynamic and static ring end face is in pure fluid lubrication state, the friction heat is extremely small and evenly emitted, the temperature has no obvious rising trend, the fluctuation amplitude is small, the radial vibration is mainly medium turbulent disturbance, the amplitude is extremely small, and has no correlation with the temperature change. The linkage of the temperature rise rate and the vibration amplitude is extremely weak, and the time sequence change curves of the two have no obvious correlation, and the Pearson correlation coefficient is small.

[0039] Specifically, the fitting pressure monitoring module sets a plurality of current adjustment coefficients to reduce the current of the suction body 5 under the condition that the fitting pressure of the fitting end face is too large, based on the first index difference between the thermal vibration coupling matching index and the first preset matching index, and the comparison result of the preset index difference. The fitting pressure monitoring module sets a plurality of current correction coefficients to increase the current of the suction body 5 under the condition that the fitting pressure of the fitting end face is too small, based on the second index difference between the thermal vibration coupling matching index and the second preset matching index, and the comparison result of the preset index difference.

[0040] Specifically, the fitting 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; The fitting pressure monitoring module determines to reduce the current of the suction body 5 by a second current adjustment coefficient based on the comparison result that the first index difference is less than the preset index difference.

[0041] Specifically, the fitting 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; The fitting 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.

[0042] Specifically, the value range of the preset index difference is set to [0.1, 0.3], and the embodiment of the application preferably 0.2; the value range of the first current adjustment coefficient is set to [0.8, 0.85], and the embodiment of the application preferably 0.83; the value range of the second current adjustment coefficient is set to [0.86, 0.9], and the embodiment of the application preferably 0.88; the value range of the first current correction coefficient is set to [1.2, 1.4], and the embodiment of the application preferably 1.3; the value range of the second current correction coefficient is set to [1.1, 1.19], and the embodiment of the application preferably 1.15.

[0043] Specifically, when the current adjustment coefficient is used to adjust the current of the suction body 5, the adjusted current value is the product of the corresponding current adjustment coefficient and the original current value of the suction body 5.

[0044] Specifically, the friction state monitoring module determines that the friction state of the fitting end face is unqualified based on the comparison result that the frequency spectrum widening index is greater than the preset widening index; The friction state monitoring module determines that the friction state of the fitting end face is qualified based on the comparison result that the frequency spectrum widening index is less than or equal to the preset widening index.

[0045] Specifically, the friction state monitoring module filters the original acoustic emission signal sequence collected by the acoustic emission sensor 16 using a band-pass filter to obtain an acoustic emission signal sequence; performs fast Fourier transform on the acoustic emission signal sequence to obtain a frequency spectrum; determines a power spectrum based on the frequency spectrum to determine the main frequency peak with the highest energy proportion in the frequency spectrum, and determines the peak energy and the main frequency of the main frequency peak; determines the half energy of 0.5 times the peak energy corresponding to two frequencies on the power spectrum, determines the absolute difference value of 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 spectral broadening index.

[0046] Specifically, the filtering range is 10 kHz-500 kHz, and the reference spectrum peak width refers to the average value of 3-5 groups of frequency spectrum peak widths calculated under the condition that the sealing state of the mechanical seal is qualified.

[0047] Specifically, the value range of the preset broadening index is set to [1.5, 3], and the embodiment of the application preferably is 2.

[0048] Specifically, the response of temperature and vibration parameters to the friction state has hysteresis. When the end face is converted from insufficient pressure to excessive pressure, the smooth rise of temperature and the gradual increase of vibration amplitude need a certain time accumulation, while the acoustic emission signal is an elastic wave released by material deformation, micro-crack expansion and particle collision in the friction process, which has a millisecond response speed and can capture the transient change of the friction state in an instant after adjustment. For example, if the current amplitude is too large during adjustment, the fitting pressure is directly converted from insufficient to excessive, the micro-protrusions of the end face immediately enter a continuous contact state, the main frequency of the acoustic emission signal quickly rises from less than 100 kHz to 100-300 kHz, and the spectral broadening index synchronously increases. Therefore, the problem of over-adjustment can be found in time before the temperature and vibration appear obvious abnormalities.

[0049] Specifically, the friction state monitoring module sets a plurality of current optimization coefficients based on the comparison result of the spectral broadening index and the preset broadening index and the preset broadening deviation, so as to reduce the current correction coefficient.

[0050] Specifically, the friction state monitoring module determines to reduce the current correction coefficient by a first current optimization coefficient based on the comparison result that the spectral broadening deviation is greater than or equal to the preset broadening deviation. The friction state monitoring module determines to reduce the current correction coefficient by a second current optimization coefficient based on the comparison result that the spectral broadening deviation is less than the preset broadening deviation.

[0051] Specifically, the spread deviation refers to the difference between the spectral spread index and the preset spread index, the preset spread deviation is set to [0.3, 0.8], the first current optimization coefficient is preferably 0.5, the value range of the first current optimization coefficient is set to [0.88, 0.92], the second current optimization coefficient is preferably 0.9, and the value range of the second current optimization coefficient is set to [0.93, 0.96], and the second current optimization coefficient is preferably 0.94.

[0052] Specifically, the current optimization coefficient is used to adjust the current correction coefficient in the following manner: the corresponding current optimization coefficient is multiplied by the current correction coefficient, and the product is the optimized current correction coefficient.

[0053] Specifically, the sealing medium monitoring module determines that the sealing performance of the mechanical seal is unqualified based on the comparison result that the change rate of the leakage amount of the sealing medium is greater than the preset change rate. The sealing medium monitoring module determines that the sealing performance of the mechanical seal is qualified based on the comparison result that the change rate of the leakage amount of the sealing medium is less than or equal to the preset change rate.

[0054] Specifically, the value range of the preset change rate is set to [3%, 8%], and the preset change rate is preferably 5%.

[0055] Specifically, the change rate of the leakage amount refers to the relative change amplitude of the volume of the leaked sealing medium per unit time.

[0056] Specifically, the sealing performance deterioration is a gradual process. In the initial stage of liquid film imbalance, the absolute value of the leakage amount is still in the design qualified interval, but the change rate of the leakage amount has already increased first. When the absolute value of the leakage amount exceeds the standard, the sealing surface has often been irreversibly damaged. The instantaneous fluctuation of the operating condition can cause the absolute value of the leakage amount to rise temporarily, but such fluctuation is occasional, and the change rate of the leakage amount will quickly fall back to the qualified interval. The leakage amount increase caused by sealing performance deterioration is continuous, and the change rate will be in the critical or unqualified interval for a long time. Using the change rate of the leakage amount to determine the sealing performance can avoid misjudging the instantaneous fluctuation of the operating condition as unqualified sealing performance, thereby improving the reliability of the monitoring determination.

[0057] Specifically, the sealing medium monitoring module sets a plurality of parameter adjustment coefficients based on the change rate difference between the change rate and the preset change rate difference when the sealing performance of the mechanical seal is unqualified.

[0058] Specifically, the sealing medium monitoring module determines to reduce the preset distribution representation parameter by the first parameter adjustment coefficient based on the comparison result that the change rate difference is greater than the preset change rate difference. The sealing medium monitoring module determines to reduce the preset distribution characteristic parameter by the second parameter adjustment coefficient based on a comparison result that the change rate difference value is less than or equal to the preset change rate difference value.

[0059] Specifically, the preset change rate difference value is set in a range of [1%, 3%], preferably 2% in the embodiment of the application, the first parameter adjustment coefficient is set in a range of [0.75, 0.85], preferably 0.8 in the embodiment of the application, and the second parameter adjustment coefficient is set in a range of [0.86, 0.9], preferably 0.89 in the embodiment of the application.

[0060] Specifically, the preset distribution characteristic parameter is adjusted by multiplying the corresponding parameter adjustment coefficient and the preset distribution characteristic parameter, and the product is the adjusted preset distribution characteristic parameter.

[0061] Specifically, when the sealing state is unqualified, it indicates that the liquid film has an irreversible deterioration trend, but at this time, the dispersion of the abrasive particle size distribution may not have reached the exceeding threshold of the original preset value, and the abrasive monitoring has a lag. Reducing the preset distribution characteristic parameter can tighten the determination threshold of the abrasive monitoring, so that it can capture the slight change of the abrasive at the early stage of the liquid film deterioration, trigger an early warning before the sealing performance is further deteriorated, and avoid the expansion of the end face damage.

[0062] So far, the technical solutions of the application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the application, and the technical solutions after the changes or replacements will fall within the protection scope of the application.

Claims

1. A split mechanical seal, characterized by, The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method.

2. The split mechanical seal of claim 1, wherein, The application relates to a mechanical seal device and a mechanical seal monitoring method.

3. The split mechanical seal of claim 2, wherein, The application relates to a mechanical seal device and a mechanical seal monitoring method.

4. The split mechanical seal of claim 3, wherein, The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method.

5. The split mechanical seal of claim 4, wherein, The application relates to a mechanical seal device and a mechanical seal monitoring method.

6. The split mechanical seal of claim 5, wherein, The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. 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The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device and a mechanical seal monitoring method. The application relates to a mechanical seal device 7. The split mechanical seal of claim 6, wherein, The friction state monitoring module determines that the friction state of the abutting end face is unqualified based on a comparison result that the spectral broadening index is greater than a preset broadening index.

8. The split mechanical seal of claim 7, wherein, The friction state monitoring module sets a plurality of current optimization coefficients to reduce the current correction coefficient based on a comparison result that a broadening deviation between the spectral broadening index and the preset broadening index and a preset broadening deviation under the condition that the friction state of the abutting end face is unqualified.

9. The split mechanical seal of claim 8, wherein, The sealing medium monitoring module determines that the sealing performance of the mechanical seal is unqualified based on a comparison result that a change rate of the leakage amount of the sealing medium is greater than a preset change rate.

10. The split mechanical seal of claim 9, wherein, The sealing medium monitoring module sets a plurality of parameter adjustment coefficients to reduce the preset distribution characteristic parameter based on a comparison result that a change rate difference between the change rate and the preset change rate and a preset change rate difference under the condition that the sealing performance of the mechanical seal is unqualified.

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