A dynamic measurement method for mechanical seal end face clearance

Abstract

This invention relates to the field of mechanical seals, specifically a dynamic measurement method for the end face clearance of a mechanical seal, comprising the following steps: S1: setting a periodic grating structure on the non-sealing surfaces of the rotating and stationary rings of the mechanical seal; S2: acquiring a dynamic image sequence of the periodic grating structure during the operation of the mechanical seal; S3: processing the acquired dynamic image sequence to extract the phase information of the periodic grating structure and obtain phase change data; S4: calculating the relative displacement and relative rotation angle between the sealing end faces of the rotating and stationary rings based on the phase change data; S5: monitoring, providing early warning, and evaluating the state of the mechanical seal. This invention provides a dynamic measurement method for the end face clearance of a mechanical seal. This invention enables non-stop, non-contact online detection of the end face clearance of a mechanical seal.

Description

Technical Field

[0001] This invention relates to the field of mechanical seals, specifically a method for dynamically measuring the clearance of the end face of a mechanical seal. Background Technology

[0002] Mechanical seals are critical components in rotating equipment used to prevent media leakage. They are widely used in petrochemical, power, pharmaceutical, and aerospace industries. Their basic structure typically includes a rotating ring, a stationary ring, a spring, and a sealing ring. They rely primarily on the tight fit between the end faces of the rotating and stationary rings to form a sealing interface and prevent fluid leakage. Theoretically, the sealing end faces should maintain a uniform and stable fit or maintain the designed clearance. However, in actual operation, the sealing end faces are easily affected by various factors, leading to deformation or relative displacement, resulting in decreased sealing performance and even causing leaks, accelerated wear, and other malfunctions.

[0003] Therefore, monitoring the gaps and deformations of sealing devices is crucial. However, current methods for measuring the gaps at the end faces of mechanical seals mainly include contact displacement sensor measurement, capacitance method, and eddy current method. These methods generally suffer from the following problems: first, they are difficult to adapt to high-speed rotation conditions, limiting sensor installation; second, their measurement accuracy is limited, making it difficult to capture gap changes at the micrometer or even sub-micrometer level; third, they are susceptible to environmental factors such as temperature and electromagnetic interference, resulting in insufficient stability and reliability; and fourth, most methods are point measurements, failing to achieve full-field, visual monitoring. In particular, the aforementioned measurement methods cannot provide non-contact monitoring of mechanical seals while the machine is rotating. Therefore, how to achieve online monitoring of minute distance changes between the rotating and stationary rings in a non-contact manner during operation has become a pressing technical challenge. Summary of the Invention

[0004] To avoid and overcome the technical problems existing in the prior art, this invention provides a dynamic measurement method for the end face clearance of a mechanical seal. This invention enables non-stop, non-contact online detection of the end face clearance of a mechanical seal.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for dynamically measuring the end face clearance of a mechanical seal includes the following steps:

[0007] S1: A periodic grating structure is set on the non-sealing surface of the dynamic ring and stationary ring of the mechanical seal;

[0008] S2: During the operation of the mechanical seal, a dynamic image sequence of the periodic grating structure is acquired;

[0009] S3: Process the acquired dynamic image sequence, extract the phase information of the periodic grating structure, and obtain phase change data;

[0010] S4: Based on phase change data, calculate the relative displacement and relative rotation angle between the sealing end faces of the rotating ring and the stationary ring;

[0011] S5: Monitor, provide early warnings, and assess the condition of mechanical seals.

[0012] As a further aspect of the present invention: in S3:

[0013] S31. Preprocess the acquired images;

[0014] S32. Perform orthogonal decomposition on the grating pattern, orthogonally decompose the two perpendicular gratings to obtain two independent unidirectional gratings, one of which is parallel to the axis of the moving ring and the stationary ring.

[0015] S33. Downsample the two independent unidirectional gratings after separation;

[0016] S34: The downsampled discontinuous pixel sequence is processed using an interpolation method to generate a continuous cloud-patterned stripe image, and the phase of the cloud-patterned stripe image is calculated.

[0017] As a further aspect of the present invention: in S33, the sampling interval for downsampling is... T , T It is the nearest integer of the grating pitch;

[0018] During downsampling, starting from the first pixel block on one side of the raster, every... T Sampling is performed on 10 pixel blocks to obtain a period of 1000 pixels. T The first discontinuous pixel block sequence;

[0019] Starting from the second pixel block, every... T Sampling is performed on 10 pixel blocks to obtain a period of 1000 pixels. T The second discontinuous pixel block sequence;

[0020] Repeat the above operations to obtain T A sequence of discontinuous pixel blocks.

[0021] As a further aspect of the present invention: in S34, intensity difference is applied to the missing parts of each discontinuous pixel block sequence to make it into a continuous and smooth cloud pattern sequence, and the cloud pattern phase is obtained after discrete Fourier transform of the cloud pattern sequence.

[0022] As a further aspect of the present invention: before the mechanical seal deforms x The phase of the moiré pattern in the direction is :

[0023]

[0024]

[0025] Mechanical seal deformation x The phase of the moiré pattern in the direction is :

[0026]

[0027]

[0028] in, Indicates the mechanical seal before deformation x The intensity of the directional cloud-like stripe image;

[0029] Indicates the deformation of the mechanical seal x The intensity of the directional cloud-like stripe image;

[0030] T Indicates the sampling interval for downsampling;

[0031] k This indicates the sequence number of the moiré pattern obtained from downsampling. ;

[0032] This represents the grating intensity amplitude.

[0033] p x Indicates the mechanical seal before deformation x grating pitch in the direction;

[0034] Indicates the deformation of the mechanical seal x grating pitch in the direction;

[0035] Indicates background intensity;

[0036] Mechanical seal deformation front and rear edges x The phase difference of the moiré pattern in the direction is

[0037] .

[0038] As a further embodiment of the present invention: in S4:

[0039] S41, with the axial directions of the moving and stationary rings as... x Direction, along the grating x The relative displacement in the direction is ;

[0040]

[0041] in, Indicates the front and rear edges of the mechanical seal deformation x directional grating phase difference,

[0042] ;

[0043] p x Indicates the mechanical seal before deformation x grating pitch in the direction;

[0044] The grating phase can be obtained from the moiré phase. :

[0045]

[0046] in This indicates that the unidirectional grating is in place after the mechanical seal deforms. x Phase of direction;

[0047] This indicates that the unidirectional grating is in place after the mechanical seal deforms. x grating pitch in the direction;

[0048] This indicates that the unidirectional grating is in place after the mechanical seal deforms. y grating pitch in the direction;

[0049] x express x The coordinates of the orientation grating;

[0050] y express y The coordinates of the orientation grating;

[0051]

[0052] grating and x The deflection angle of the direction is :

[0053]

[0054] Due to the initial time x Main direction grating and x If the direction of rotation is 90°, then the change in angle is... x for:

[0055]

[0056] S42. Calculate the sealing end face along the calculation steps in S41. y Relative displacement in direction and along y The deflection angle of the direction.

[0057] As a further aspect of the present invention: exist( -n , n Within the threshold range of ), it is enveloped by (-π, π), and after partial derivative correction:

[0058]

[0059] in, Indicates the location at coordinates The grating phase difference before and after deformation of the mechanical seal at the point;

[0060] Indicates the location at coordinates The grating phase difference before and after deformation of the mechanical seal at the point.

[0061] As a further aspect of the present invention: by capturing images of the displacements of the moving and stationary rings during the operation of the mechanical seal, the amount of gap change can be obtained. d Relative angle change :

[0062]

[0063]

[0064] in, The displacement of the grating attached to the stationary ring;

[0065] The displacement of the grating attached to the moving ring;

[0066] This represents the change in the angle of the grating attached to the stationary ring.

[0067] This represents the change in the angle of the grating attached to the moving ring.

[0068] An electronic device is characterized in that it includes a processor, an input device, an output device, and a memory, wherein the processor, the input device, the output device, and the memory are connected in sequence, the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions to execute the dynamic measurement method for the end face gap of a mechanical seal.

[0069] A readable storage medium, characterized in that the storage medium stores a computer program, the computer program including program instructions, which, when executed by a processor, cause the processor to perform the aforementioned method for dynamically measuring the gap between the end faces of a mechanical seal.

[0070] Compared with the prior art, the beneficial effects of the present invention are:

[0071] 1. This invention, without damaging the sealing structure or affecting its operation, only sets a grating structure on the surface of the rotating and stationary rings, which has almost no impact on the overall operation of the sealing structure. Based on this, by performing image acquisition and processing on the grating, real-time, non-stop, and non-contact online monitoring of the mechanical seal can be performed under high-speed rotation. By judging the relative displacement of the sealing end face along the axial direction and the relative rotation angle around the shaft, the working status of the sealing end face can be fully reflected.

[0072] 2. This invention separates the deformation of a two-dimensional grating into two independent one-dimensional directions through orthogonal decomposition, allowing the calculation of displacement and rotation angles to be performed independently and avoiding mutual interference. By generating mottled fringes, the high-frequency grating signal is converted into a low-frequency mottled signal, amplifying minute deformation information and making the measurement more sensitive and reliable. Sampling at integer multiples of the grating pitch ensures the accuracy and consistency of mottled signal extraction. After generating T discontinuous sequences, it is equivalent to observing the mottled from different starting points, providing a sufficient data foundation for the subsequent generation of a continuous and complete full-field phase map.

[0073] 3. This invention transforms discrete pixel sequences into continuous cloud-pattern images through interpolation, thereby calculating the phase information of the entire observation area. It uses discrete Fourier transform for phase extraction, extracting accurate and continuous phase values ​​from the cloud-pattern stripes, providing reliable input for subsequent calculations.

[0074] 4. This invention significantly reduces the measurement cost of the sealing end face gap. It does not require expensive sensors. Only a high-speed camera is needed to acquire images of the grating on the surface of the object being measured. With the help of an algorithm, the motion displacement can be obtained, which has a very good anti-interference effect. Attached Figure Description

[0075] Figure 1 This is a schematic diagram of the structure of the present invention.

[0076] Figure 2 This is a schematic diagram illustrating the method of setting the grating pattern in this invention.

[0077] Figure 3 This is a schematic diagram of the phase analysis process in this invention. Detailed Implementation

[0078] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0079] Please see Figures 1-3In this embodiment of the invention, a method for dynamically measuring the clearance of a mechanical seal end face includes the following steps:

[0080] S1: A periodic grating structure is set on the non-sealing surface of the dynamic ring and stationary ring of the mechanical seal;

[0081] The grating pattern is not limited to a specific shape and can be an orthogonal grid, one-dimensional grating lines, a dot matrix pattern, a number / letter array, a periodic pattern at ±45° or other arbitrary angles. In this embodiment, an orthogonal grid is selected as the grating pattern, and the grating pitch is set to 2mm.

[0082] The fabrication method of the grating is not limited to any particular process; it can employ laser marking, nanoimprinting, plasma etching, photolithography with or without a mask, grating bonding, etc. The grating period can be flexibly adjusted according to the measurement accuracy requirements; the smaller the period, the higher the measurement resolution. During setup, the grating should be tightly attached to the surface of the part being measured, and its own mass should be much smaller than the locking object to avoid introducing additional inertia or eccentricity. This embodiment uses laser marking technology or a high-adhesion grating transfer sticker solution. Laser marking uses an ultraviolet laser marking machine to directly etch a periodic grid onto the surface of the sealing ring, ensuring clear and uniform lines. When using a grating transfer sticker, a high-temperature resistant adhesive film grating is selected and bonded to the surface by pressing to prevent it from falling off during rotation. After the grating is fabricated, its pattern integrity and contrast need to be checked to ensure the quality of subsequent image acquisition.

[0083] The aforementioned mechanical seals can also be replaced by any one of the following: dry gas seals, liquid film seals, gas film seals, magnetic seals, floating ring seals, spiral seals, labyrinth seals, combination seals, intelligent seals, self-healing seals, nano seals, and biomimetic seals. Mechanical seals can be applied to pumps, compressors, reactors, centrifuges, turbines, engines, transmissions, reducers, mixers, agitators, fans, vacuum equipment, hydraulic equipment, pneumatic equipment, and related machinery.

[0084] S2: During the operation of the mechanical seal, a dynamic image sequence of the periodic grating structure is acquired;

[0085] First, a detection system is set up, and a stationary ring and a moving ring equipped with gratings are installed in a rotating device. The stationary ring is fixed, and the moving ring rotates with the main shaft.

[0086] A high-speed camera with a frame rate of at least 2000fps is used, equipped with a telecentric lens to reduce perspective errors. The camera is fixed on a vibration-proof platform, with the lens directly facing the sealed grating area to ensure the grating is always centered in the field of view. A uniform LED cold light source is used, obliquely illuminating the grating surface at a certain angle to enhance image contrast. The high-speed camera can also be replaced with a CCD, CMOS, microscope, endoscope, fiber optic imaging system, infrared imaging system, or X-ray imaging system.

[0087] After starting the rotating device, the rotational speed of the moving ring is set to 100 rpm. During rotation, an initial zero-load grating image is acquired as a reference. The high-speed camera continuously acquires dynamic grating images through the observation window, covering multiple rotation cycles to ensure the complete motion process is captured. During acquisition, the camera focal length, position, and lighting conditions remain constant to avoid external interference. Under operating conditions, the gap between the moving and stationary rings undergoes slight changes due to centrifugal force, friction, and fluid pressure. As a displacement carrier, the grating's periodic fringes deform with the gap change. The high-speed camera acquires real-time motion images of the gratings on the surfaces of the moving and stationary rings throughout the entire process and transmits them to the data processing and analysis module.

[0088] To ensure measurement stability, the high-speed camera and light source are fixed with a vibration-damping bracket, and an external transparent protective cover is provided to isolate the grating imaging quality from the influence of lubricant and dust. The grating material is a high-temperature resistant and wear-resistant composite film to ensure that the grating fringes are not damaged under long-term rotation and friction.

[0089] S3: Process the acquired dynamic image sequence, extract the phase information of the periodic grating structure, and obtain phase change data;

[0090] S31. Preprocess the acquired images;

[0091] The acquired images are first preprocessed by cropping and rotating, and then converted to grayscale to obtain grayscale images.

[0092] S32. Perform orthogonal decomposition on the grating pattern, orthogonally decomposing the gratings in two perpendicular directions to obtain two independent unidirectional gratings. The two perpendicular gratings are decomposed into two independent unidirectional gratings, and each directional grating is used for phase analysis and displacement calculation in its respective direction. When using orthogonal gratings, a two-dimensional Fourier filter or low-pass filter is used to separate the gratings. x and y Single-frequency grating component in the direction.

[0093] One of the unidirectional gratings is parallel to the axes of the moving ring and the stationary ring;

[0094] The grating phase processing methods are the same in both directions, so only the phase analysis process in one direction will be described. Assume that the extracted... x The grating of the direction is defined as follows: p x ,

[0095] Before the mechanical seal deforms, x The light intensity of the directional grating is :

[0096] ;

[0097] After the mechanical seal deforms, x The light intensity of the directional grating is :

[0098] ;

[0099] Caused by deformation of mechanical seal x The phase difference corresponding to the change in the directional grating is :

[0100]

[0101] in, This represents the grating intensity amplitude.

[0102] x express x The coordinates of the orientation grating;

[0103] Indicates background intensity;

[0104] p x Indicates the mechanical seal before deformation x grating pitch in the direction;

[0105] Indicates the deformation of the mechanical seal x grating pitch in the direction;

[0106] Indicates the mechanical seal before deformation x The grating phase in the direction;

[0107] Indicates the deformation of the mechanical seal x The grating phase in the direction.

[0108] S33. Downsample the two independent unidirectional gratings after separation;

[0109] The downsampling sampling interval is T , T It is the nearest integer of the grating pitch;

[0110] During downsampling, starting from the first pixel block on one side of the raster, every... T Sampling is performed on 10 pixel blocks to obtain a period of 1000 pixels. T The first discontinuous pixel block sequence;

[0111] Starting from the second pixel block, every... T Sampling is performed on 10 pixel blocks to obtain a period of 1000 pixels. T The second discontinuous pixel block sequence;

[0112] Repeat the above operations to obtain T A sequence of discontinuous pixel blocks of grayscale.

[0113] S34: The downsampled discontinuous pixel sequence is processed using an interpolation method to generate a continuous cloud-patterned stripe image, and the phase of the cloud-patterned stripe image is calculated.

[0114] Intensity difference is applied to the gaps in each discontinuous pixel block sequence to transform it into a continuous and smooth moiré pattern sequence. The moiré pattern phase is obtained by performing a discrete Fourier transform on the moiré pattern sequence. .

[0115] The interpolation method used is Makima interpolation, and the intensity of the interpolated moiré pattern image is... :

[0116]

[0117] After Discrete Fourier Transform, before deformation of the mechanical seal x The phase of the moiré pattern in the direction is :

[0118]

[0119]

[0120] Mechanical seal deformation x The phase of the moiré pattern in the direction is :

[0121]

[0122]

[0123] in, Indicates the mechanical seal before deformation x The intensity of the directional cloud-like stripe image;

[0124] Indicates the deformation of the mechanical seal x The intensity of the directional cloud-like stripe image;

[0125] T Indicates the sampling interval for downsampling;

[0126] k This indicates the sequence number of the moiré pattern obtained from downsampling. ;

[0127] This represents the grating intensity amplitude.

[0128] p x Indicates the mechanical seal before deformationx grating pitch in the direction;

[0129] Indicates the deformation of the mechanical seal x grating pitch in the direction;

[0130] Indicates background intensity.

[0131] The phase difference of the cloud pattern is for:

[0132]

[0133] The moiré phase difference calculated here refers to x Phase difference of moiré patterns in the direction, y The phase difference of the moiré pattern in the direction is calculated in the same way as above.

[0134] Moiré phase difference and grating fringe phase difference The following relationship exists:

[0135] ;

[0136] S4: Based on phase change data, calculate the relative displacement and relative rotation angle between the sealing end faces of the rotating ring and the stationary ring;

[0137] exist( -n , n Within the threshold range of ), it is enveloped by (-π, π), and after partial derivative correction:

[0138]

[0139] in, Indicates the location at coordinates The grating phase difference before and after deformation of the mechanical seal at the point;

[0140] Indicates the location at coordinates The grating phase difference before and after deformation of the mechanical seal at the point.

[0141] Phase boundary discontinuities can be eliminated by using a phase unwrapping algorithm.

[0142] S41, with the axial directions of the moving and stationary rings as... x Direction, along the grating x The relative displacement in the direction is ;

[0143]

[0144] grating and x The deflection angle of the direction is :

[0145]

[0146] in, This indicates that the unidirectional grating is in place after the mechanical seal deforms. x Phase of direction;

[0147] This indicates that the unidirectional grating is in place after the mechanical seal deforms. x grating pitch in the direction;

[0148] This indicates that the unidirectional grating is in place after the mechanical seal deforms. y grating pitch in the direction;

[0149] x express x The coordinates of the orientation grating;

[0150] y express y The coordinates of the directional grating.

[0151] Due to the initial time x Main direction grating and x If the direction of rotation is 90°, then the change in angle is... x :

[0152]

[0153] S42. Calculate the sealing end face along the calculation steps in S41. y Relative displacement in direction and along y The deflection angle of the direction.

[0154] The change in clearance can be obtained by capturing images of the displacement of the moving and stationary rings during the operation of the mechanical seal. d Relative angle change :

[0155]

[0156]

[0157] in The displacement of the grating attached to the stationary ring;

[0158] The displacement of the grating attached to the moving ring;

[0159] This represents the change in the angle of the grating attached to the stationary ring.

[0160] This represents the change in the angle of the grating attached to the moving ring.

[0161] S5: Monitor, provide early warnings, and assess the condition of mechanical seals.

[0162] Since high-speed cameras capture a large number of images, displacement curves can be plotted by selecting specific points and following the order of the captured images to find patterns of change.

[0163] During the measurement process, gratings can be applied to both the stationary and rotating rings. Different styles of gratings can be made for differentiation, or different markings can be added next to the gratings for distinction. Based on the above derivation, for the specific performance results of the seal, the displacement of the grating applied to the stationary ring can be defined as... u x0 The gratings on the moving ring are kept horizontal with those on the stationary ring. To more easily represent displacement changes and axis offset, two gratings can be attached horizontally to the moving ring. The displacement of the grating closer to the stationary ring is defined as... u x1 The displacement of the grating that is far from the stationary ring is defined as u x2 Regarding the gap change, the difference between the displacements of the moving and stationary rings caused by factors such as vibration can reflect the change in the gap value. After the above analysis process, the raster region of each image acquired by the high-speed camera has a full-field displacement distribution relative to the first image. The displacement of the raster region of each moving and stationary ring represents their respective displacements during operation; therefore, the difference in displacement between the moving and stationary rings can represent the gap change value. x The direction of the gap can be changed by ( - ) can be observed by how it changes over time, or it can be observed by ( -u x0 Observe how it changes over time. - )and( - The relationship between the two values ​​can be used as a further verification of the change in the axis angle. If an axis offset occurs, the two values ​​will not change synchronously, and this can be used to determine whether there is a V-shaped eccentricity.

[0164] Another embodiment of this application is an electronic device.

[0165] The electronic device can be the mobile device itself, or a standalone device that can communicate with the mobile device to receive the collected input signals from it and send the selected target decision behavior to it.

[0166] Electronic devices include one or more processors and memory.

[0167] A processor can be a central processing unit (CPU) or other form of processing unit with data processing and / or instruction execution capabilities, and can control other components in an electronic device to perform desired functions.

[0168] The memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and a processor may execute the program instructions to implement a dynamic measurement method for the mechanical seal end face clearance according to the various embodiments of this application described above.

[0169] In one example, the electronic device may also include input and output devices, which are interconnected via a bus system and / or other forms of connection. For example, the input device may include various devices such as on-board diagnostics (OBD), cameras, industrial cameras, etc. The input device may also include, for example, a keyboard, a mouse, etc. The output device may include, for example, a monitor, speakers, a printer, and communication networks and their connected remote output devices, etc.

[0170] In addition, depending on the specific application, electronic devices may include any other suitable components.

[0171] Another embodiment of this application may be a computer program product, which includes computer program instructions that, when executed by a processor, cause the processor to perform the calculation steps described in the above-described method for dynamic measurement of mechanical seal end face clearance according to various embodiments of this application.

[0172] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0173] Furthermore, embodiments of this application may also be computer-readable storage media storing computer program instructions that, when executed by a processor, cause the processor to perform a dynamic measurement method for the mechanical seal end face clearance as described in this specification.

[0174] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may, for example, include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0175] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0176] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

Claims

1. A method of dynamically measuring a mechanical seal end face gap, characterized by, Includes the following steps: S1: A periodic grating structure is set on the non-sealing surface of the dynamic ring and stationary ring of the mechanical seal; S2: During the operation of the mechanical seal, a dynamic image sequence of the periodic grating structure is acquired; S3: Process the acquired dynamic image sequence, extract the phase information of the periodic grating structure, and obtain phase change data; S31. Preprocess the acquired images; S32. Perform orthogonal decomposition on the grating pattern, orthogonally decompose the two perpendicular gratings to obtain two independent unidirectional gratings, one of which is parallel to the axis of the moving ring and the stationary ring. S33. Downsample the two independent unidirectional gratings after separation; The sampling interval for down-sampling is T , T is the nearest integer to the grating pitch; When down-sampling, starting from the first pixel block on one side of the grating, every T pixel block is sampled to obtain a first sequence of discontinuous pixel blocks with a period of T ​ Then, starting from the second pixel block, every other pixel block is sampled to obtain a second sequence of discontinuous pixel blocks with a period of T T ​​ The above operation is repeated to obtain T a sequence of interlaced pixel blocks; S34: The downsampled discontinuous pixel sequence is processed using an interpolation method to generate a continuous cloud-patterned stripe image, and the phase of the cloud-patterned stripe image is calculated. S4: Based on phase change data, calculate the relative displacement and relative rotation angle between the sealing end faces of the rotating ring and the stationary ring; S41, the axis direction of the static ring is x direction, the relative displacement of the gratings along x direction is ; wherein represents the grating phase difference along the direction of the mechanical seal before and after deformation x direction of the mechanical seal before and after deformation ； p x Indicates the mechanical seal before deformation x grating pitch in the direction; The grating phase can be obtained from the moiré phase. : in This indicates that the unidirectional grating is in place after the mechanical seal deforms. x Phase of direction; This indicates that the unidirectional grating is in place after the mechanical seal deforms. x grating pitch in the direction; This indicates that the unidirectional grating is in place after the mechanical seal deforms. y grating pitch in the direction; x express x The coordinates of the orientation grating; y express y The coordinates of the orientation grating; grating and x The deflection angle of the direction is : Due to the initial time x Main direction grating and x If the direction of rotation is 90°, then the change in angle is... x for: S42. Calculate the sealing end face along the calculation steps in S41. y Relative displacement in direction and along y The angle of deflection of direction; S5: Monitor, provide early warnings, and assess the condition of mechanical seals.

2. The method for dynamically measuring the end face clearance of a mechanical seal according to claim 1, characterized in that, In S34, intensity difference is applied to the missing parts of each discontinuous pixel block sequence to transform it into a continuous and smooth cloud pattern sequence. The cloud pattern phase is obtained after discrete Fourier transform of the cloud pattern sequence.

3. The method for dynamically measuring the end face clearance of a mechanical seal according to claim 2, characterized in that, Before mechanical seal deformation x The phase of the moiré pattern in the direction is : Mechanical seal deformation x The phase of the moiré pattern in the direction is : in, Indicates the mechanical seal before deformation x The intensity of the directional cloud-like stripe image; Indicates the deformation of the mechanical seal x The intensity of the directional cloud-like stripe image; T Indicates the sampling interval for downsampling; k This indicates the sequence number of the moiré pattern obtained from downsampling. ; This represents the grating intensity amplitude. p x Indicates the mechanical seal before deformation x grating pitch in the direction; Indicates the deformation of the mechanical seal x grating pitch in the direction; Indicates background intensity; Mechanical seal deformation front and rear edges x The phase difference of the moiré pattern in the direction is 。 4. The method for dynamically measuring the end face clearance of a mechanical seal according to claim 1, characterized in that, exist( -n , n Within the threshold range of ), it is enveloped by (-π, π), and after partial derivative correction: in, Indicates the location at coordinates The grating phase difference before and after deformation of the mechanical seal at the point; Indicates the location at coordinates The grating phase difference before and after deformation of the mechanical seal at the point.

5. The method for dynamically measuring the end face clearance of a mechanical seal according to claim 1, characterized in that, The change in clearance can be obtained by capturing images of the displacement of the moving and stationary rings during the operation of the mechanical seal. d Relative angle change : in, The displacement of the grating attached to the stationary ring; The displacement of the grating attached to the moving ring; This represents the change in the angle of the grating attached to the stationary ring. This represents the change in the angle of the grating attached to the moving ring.

6. An electronic device, characterized in that, The device includes a processor, an input device, an output device, and a memory, which are connected in sequence. The memory is used to store a computer program, which includes program instructions. The processor is configured to call the program instructions to execute a dynamic measurement method for the mechanical seal end face clearance as described in claim 1 or 2.

7. A readable storage medium, characterized in that, The storage medium stores a computer program, which includes program instructions that, when executed by a processor, cause the processor to perform a dynamic measurement method for the mechanical seal end face clearance as described in claim 1 or 2.

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