Rotor rub-impact detection instrument based on acoustics

Abstract

The utility model discloses a rotor rub-impact detection instrument based on acoustics, and belongs to the technical field of nondestructive testing. A rotor rub-impact detection instrument based on acoustics comprises an instrument host, the instrument host is connected with a plurality of ultrasonic probes, a display screen is arranged in front of the instrument host, an AD circuit and a microprocessor are arranged in the instrument host, the ultrasonic probes are electrically connected with the AD circuit, the AD circuit is electrically connected with the microprocessor, and the microprocessor is electrically connected with the display screen. The microprocessor is electrically connected with the display screen; the device has the advantages of being high in detection efficiency, simple and convenient to operate and capable of reducing interference of strong noise to detection personnel.

Description

Technical Field

[0001] The utility model relates to the technical field of nondestructive testing, in particular to an acoustic-based rotor friction testing instrument. Background Art

[0002] Dynamic and static friction refers to the phenomenon that vibration occurs due to collision and friction between the rotor and stator in a large generator. Dynamic and static friction is the most common and most harmful mechanical vibration failure. There are many reasons for dynamic and static friction. In essence, it is mainly due to the small gap between the rotor and the stator. At the same time, the dynamic and static gap is uneven along the circumferential direction due to installation and maintenance, or due to dynamic and static friction, collision, etc. caused by heat deformation and deviation of the cylinder and bearing seat, which leads to vibration.

[0003] As large steam turbine generator sets develop towards high parameters and large capacity, the dynamic and static clearances of the turbine are getting smaller and smaller, and the possibility of friction is increasing; the opportunities for dynamic and static friction of oil seals, oil baffles, and partition steam seals are also increasing, and the sealing pads of hydrogen-cooled generators will often experience dynamic and static friction.

[0004] At present, the incidence of friction vibration failures in large units is second only to the incidence of mass imbalance failures, becoming the second largest type of vibration failure in large units.

[0005] Friction causes the rotor to produce very complex movements. In mild cases, it causes strong vibrations in the unit, and in severe cases, it can cause permanent bending of the shaft, or even damage the entire shaft system. In recent years, many units above 100MW have experienced shaft bending accidents. Therefore, accurate analysis and diagnosis of friction faults are of great significance to ensure the safe and stable operation of the unit and prevent major accidents.

[0006] The frequency range of sound that the human ear can hear is 20~20kHz, below 20Hz is infrasound, and above 20kHz is ultrasound. The effective conversation sound range of human beings is 500~4000Hz, and 12~16kHz is the highest audible frequency, which is the high-frequency overtone band of some high-pitched musical instruments and high-pitched percussion instruments.

[0007] The human ear can hear sounds, but if the pitch of the sound is too low, it cannot be heard; and if the sound is too far away, it cannot be heard either.

[0008] When a friction fault occurs, there will be physical phenomena such as displacement vibration, audible sound (20Hz~20kHz), low frequency (tens of kHz), and ultrasonic waves. The traditional method is for the inspector to use a stethoscope to repeatedly listen to the cylinder body, shaft seal, support bearing and other stationary parts one point at a time, and then manually judge whether there is friction and the degree of the fault by listening to the sound characteristics with the ears. This method requires a high level of experience from the personnel, and it is impossible to monitor and record in real time, let alone monitor multiple points at the same time. Eddy current displacement sensors are also used to collect vibration signals for fault diagnosis, but there are many sources of vibration fault signals, and it is difficult to distinguish friction fault signals.

[0009] For example, the invention patent (publication number CN110469371A): a method for solving dynamic and static friction failures during the startup of large-capacity steam turbines. The method is: two mutually perpendicular eddy current sensors installed on each bearing are used to measure the relative vibration displacement of the rotor shaft diameter, and then the position change of the rotor shaft diameter in the bearing is used to determine whether there is dynamic and static friction. The defects are: this method is deployed on-site for fixed-point monitoring and is not suitable for portable inspections; installing sensors in the bearing will destroy the integrity of the bearing and affect the overall performance of the equipment to a certain extent.

[0010] The utility model patent (publication number CN111413081A) is an online monitoring device for rotor friction of a steam turbine generator set. Its principle is: a vibration sensor is installed on the rotor, and then the characteristic frequency of the vibration signal of the entire generator set is received at one point to determine whether there is dynamic or static friction. Its defects are: there are many sources of vibration fault signals, and it is difficult to distinguish the friction fault signal by relying on one receiving point; the rotors of most units are sealed in the casing, and it is impossible to temporarily install a vibration sensor, which makes its adaptability poor.

[0011] The invention patent (publication number CN112858485A) is a method for diagnosing rotor rubbing fault acoustic emission. The method proposes to analyze the characteristic frequency of the acoustic emission signal to determine whether there is a rubbing fault. However, it does not state the key points such as hardware solution, sensor type, and deployment method.

[0012] The above methods and devices have the disadvantages of low detection efficiency, inability to effectively detect rubbing signals, inability to detect early weak rubbing faults, and high missed detection rate under the strong noise and frequency vibration conditions of large units. Utility Model Content

[0013] The utility model aims to solve the problem that it is difficult to detect rubbing faults by artificial auscultation or equipment monitoring rubbing signals in the existing rubbing fault detection process, and proposes a rotor rubbing detection instrument based on acoustics.

[0014] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0015] A rotor rubbing detection instrument based on acoustics comprises an instrument mainframe, the instrument mainframe is connected to a plurality of ultrasonic probes, a display screen is arranged in front of the instrument mainframe, an AD circuit and a microprocessor are arranged inside the instrument mainframe, the ultrasonic probe is electrically connected to the AD circuit, the AD circuit is electrically connected to the microprocessor, and the microprocessor is electrically connected to the display screen.

[0016] Furthermore, the ultrasonic probe is a magnetic probe.

[0017] Furthermore, the ultrasonic probe comprises a probe body, and a magnetic seat is provided at the front end of the probe body.

[0018] Furthermore, a first warning light is provided at the rear end of the probe body.

[0019] Furthermore, the instrument also includes a wireless sound and light alarm, a wireless signal transmitter is arranged inside the instrument host, a wireless signal receiver is arranged inside the wireless sound and light alarm, and the wireless sound and light alarm is electrically connected to the instrument host.

[0020] Furthermore, a second warning light is arranged in front of the wireless sound and light alarm.

[0021] Furthermore, a second alarm speaker is arranged in front of the wireless sound and light alarm.

[0022] Furthermore, a first alarm speaker is arranged in front of the instrument host.

[0023] Furthermore, an alarm light is arranged in front of the instrument host.

[0024] Compared with the prior art, the utility model provides an acoustic-based rotor friction detection instrument, which has the following beneficial effects:

[0025] The utility model discloses an acoustic-based rotor rubbing detection instrument. When in use, a plurality of ultrasonic probes are installed at different positions of a device to be detected. The ultrasonic probes collect ultrasonic signals emitted by the vibration of the device to be detected, convert them into analog voltage signals, and send them to an AD sampling circuit. The AD sampling circuit converts the analog voltage signals into (amplitude-time) time domain signals in a digital signal mode, and sends them to a microprocessor. The microprocessor displays the digital signals on a display screen. A staff member determines whether a rubbing fault exists through the signal information displayed on the display screen, and can confirm the location of the fault at one time. Compared with the prior art, the detection efficiency and accuracy are significantly improved, and the difficulty of fault judgment is reduced.

[0026] Other advantages, objectives and features of the present invention will be described in the following specification to some extent; and will be apparent to those skilled in the art based on the following examination and research; or, may be taught from the practice of the present invention to some extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0028] Figure 2 This is a schematic diagram of the structure of the magnetic suction probe of the utility model;

[0029] Figure 3 This is a schematic diagram of the structure of the sound and light alarm of the utility model;

[0030] Figure 4 It is a schematic diagram for explaining the working process of the present utility model.

[0031] In the figure:

[0032] 1. Instrument host; 2. Display screen; 3. First alarm speaker; 4. Alarm light; 5. Ultrasonic probe; 51. First warning light; 52. Magnetic base; 6. Wireless sound and light alarm; 61. Second warning light; 62. Second alarm speaker. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0034] Reference Figures 1 to 4 The utility model discloses an acoustic-based rotor friction detection instrument, comprising an instrument host 1, wherein the instrument host 1 is connected to a plurality of ultrasonic probes 5, a display screen 2 is arranged in front of the instrument host 1, an AD circuit and a microprocessor are arranged inside the instrument host 1, the ultrasonic probes 5 are electrically connected to the AD circuit, the AD circuit is electrically connected to the microprocessor, and the microprocessor is electrically connected to the display screen 2.

[0035] In the present application, the number of ultrasonic probes 5 is taken as 1 to 20, and a wide-band microphone probe is selected with a signal frequency acceptance range of 20Hz to 100kHz, which is used to monitor signals in the full frequency domain, from early weak signals to the frequency band audible to the human ear, and then to the ultrasonic frequency band, so as to facilitate the detection of vibration signals in the early stage of rubbing faults. When in use, the front end of the probe is attached to stationary parts such as the cylinder body, shaft seal, and support bearings. The closer the probe is to the rubbing signal source, the stronger the signal amplitude will be.

[0036] By using a plurality of ultrasonic probes 5 arranged at multiple points, the inspection efficiency is improved and the missed inspection rate is reduced.

[0037] The ultrasonic probe 5 converts the ultrasonic signal (vibration signal) of the device vibration into an analog voltage signal. The AD sampling circuit in the host simultaneously samples the analog voltage signals of the ultrasonic probe 5 of channels 1 to 20, and then converts them into digital signals. The digital signal is a (amplitude-time) time domain signal, and the digital signal is sent to the microprocessor. The microprocessor operates the digital signal through the FFT algorithm to obtain a (amplitude-frequency) frequency domain signal, that is, the audible sound characteristic frequency and ultrasonic characteristic frequency of the collected signal are obtained.

[0038] The microprocessor sends the obtained (amplitude-frequency) frequency domain signal to the display screen 2, which simultaneously displays the audio spectrum of the (amplitude-frequency) frequency domain signal calculated from the audio signal detected by the 1st to 20th ultrasonic probe 5, including waveform, amplitude, frequency, and subsequent alarm information and other monitoring data.

[0039] The audio spectrum on the display screen 2 is mainly divided into two forms, one is a stable state, and the other is an unstable state. In the stable state, the frequency domain and amplitude of the noise generated by the mechanical, gap air, and electromagnetic of the generator set are basically stable. In the unstable state, the rubbing signal occurs randomly, and it is a non-continuous and non-steady-state deformation wave. Its frequency domain and amplitude are not fixed values. The detection personnel can easily judge whether the unstable state is a rubbing signal by comparing the unstable state with the stable state. For example, when the characteristic frequency of the collected signal is not within the inherent range of the generator set and the instantaneous amplitude is strong, it can be determined that there is a rubbing signal.

[0040] When the rubbing signal is detected, the ultrasonic probes 5 that do not show an unstable state are excluded. Among the ultrasonic probes 5 that show an unstable state, the closer to the rubbing signal source, the stronger the unstable signal, so as to determine which ultrasonic probe 5 the rubbing fault is near or between which ultrasonic probes 5 it is located.

[0041] The ultrasonic probe 5 is a magnetic probe.

[0042] The magnetic probe can be easily connected to the device to be detected by magnetic attraction. It can be attached to the surface of the device to be detected without damaging the structure of the device to be detected. It is easy to take and place, and easy to move. It is convenient to arrange multiple ultrasonic probes 5 for detection at one time, and it is also convenient to place in some small spaces.

[0043] The ultrasonic probe 5 comprises a probe body, and a magnetic seat 52 is arranged at the front end of the probe body.

[0044] When in use, the probe body is adsorbed on the steel casing of the generator set by the magnetic seat 52, close to the cylinder body, shaft seal, support bearing and other stationary parts.

[0045] A first warning light 51 is provided at the rear end of the probe body.

[0046] After the microprocessor processes the digital signal, in addition to sending the audio spectrum to the display screen 2, it also automatically determines whether there is an unstable signal through its own calculations. Only when the frequency domain and amplitude of the collected signal are not within the solid-state domain data range, it will detect whether the signal is an unstable signal, and further determine whether it is "suspected collision", effectively filtering out environmental noise and avoiding noise interference.

[0047] If there is an unstable signal and it is determined to be "suspected friction", a signal is sent to the first warning light 51 on the corresponding ultrasonic probe 5. The first warning light 51 flashes to remind the detection personnel that the signal detected by the ultrasonic probe 5 contains an unstable signal, that is, a friction failure may occur near the ultrasonic probe 5, which is convenient for the detection personnel to quickly find the ultrasonic probe 5 containing the unstable signal.

[0048] The instrument further comprises a wireless sound and light alarm 6 . A wireless signal transmitter is arranged inside the instrument host 1 . A wireless signal receiver is arranged inside the wireless sound and light alarm 6 . The wireless sound and light alarm 6 is electrically connected to the instrument host 1 .

[0049] There is a wireless connection between the wireless sound and light alarm 6 and the instrument host 1. The wireless sound and light alarm 6 is used for the detection personnel to carry with them during inspections. When the instrument host 1 automatically determines that there is "suspected friction", in addition to sending a signal to the first warning light 51, it also sends a signal to the wireless sound and light alarm 6 to remind the detection personnel that "suspected friction" is detected, which makes it easier for the detection personnel to stay away from the equipment to be tested. There is no need for the detection personnel to stand guard at close range next to the noisy unit, reducing the intrusion of strong noise on the detection personnel.

[0050] A second warning light 61 is arranged in front of the wireless sound and light alarm 6 .

[0051] After receiving the signal sent by the instrument host 1, the wireless sound and light alarm 6 controls the second warning light 61 to flash, reminding the inspection personnel to pay attention to the alarm information in time.

[0052] A second alarm speaker 62 is arranged in front of the wireless sound and light alarm 6 .

[0053] In addition to reminding the inspector by flashing the warning light, the wireless sound and light alarm 6 also emits an alarm sound through the second alarm speaker 62. The coordination of sound and light can avoid the situation where the inspector fails to see or hear one of the alarm messages.

[0054] A first alarm speaker 3 is arranged in front of the instrument host 1 .

[0055] When the inspector is near the instrument host 1 and carries the wireless sound and light alarm 6, when the instrument host 1 detects "suspected rubbing", the first alarm speaker 3 is activated to emit an alarm to remind the inspector that "suspected rubbing" is detected.

[0056] An alarm light 4 is provided on the front of the instrument main body 1 .

[0057] Since there are a large number of ultrasonic probes 5 and their distribution is relatively scattered, the instrument host 1 and the ultrasonic probe 5 are not necessarily in the same field of view. When the instrument host 1 detects "suspected friction", in addition to issuing an alarm to remind the detection personnel, the alarm light 4 can also flash to remind the detection personnel.

[0058] In the present application, the first alarm speaker 3 and the second alarm speaker 62 can choose buzzers, and the alarm light 4, the first warning light 51, and the second warning light 61 can all use LED light sources. The LED light on the probe flashes green when there is no alarm signal in normal operation, and flashes red when there is an alarm signal, which can clearly indicate whether there is any friction fault at the detection point of the probe.

[0059] Working principle: When in use, the ultrasonic probe 5 is adsorbed on the steel casing of the generator set near the cylinder body, shaft seal, support bearing and other stationary parts through the magnetic seat 52. The instrument host 1 is turned on, and the initialization information and the waveform, amplitude, frequency, alarm and other monitoring data of each signal will be displayed on the display screen 2. Continuous monitoring and recording for several hours to dozens of hours can be carried out at the same time.

[0060] When the instrument host 1 detects an unstable signal, if it is determined not to be "suspected rubbing", normal detection will continue; if it is determined to be "suspected rubbing", the instrument host 1 will control the activation of the first alarm speaker 3, the alarm light 4, the first warning light 51, the second warning light 61, and the second alarm speaker 62 to remind the detection personnel that there may be a rubbing fault.

[0061] After the inspection personnel arrive at the scene, they determine whether the unstable signal is a friction fault based on the audio frequency spectrum displayed on the display screen 2. If it is not a friction fault, the first alarm speaker 3, the alarm light 4, the first warning light 51, the second warning light 61, and the second alarm speaker 62 are restored to the initial off state, and a decision is made as to whether the inspection is to be ended. If it is a friction fault, the first warning light 51 on the ultrasonic probe 5 is checked. When it flashes in red, it indicates that there is a friction fault between the rotor and the stator in the steel shell.

[0062] The above is only a preferred specific implementation method of the utility model, but the protection scope of the utility model is not limited to this. Any inspector familiar with the technical field within the technical scope disclosed by the utility model, according to the technical scheme and utility model concept of the utility model, shall be covered by the protection scope of the utility model.

[0063] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, in the absence of mutual contradiction, test personnel in this field may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0064] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary inspectors in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An acoustic-based rotor rubbing detection instrument, comprising an instrument host (1), characterized in that: The instrument main body (1) is connected to a plurality of ultrasonic probes (5); a display screen (2) is arranged in front of the instrument main body (1); an AD circuit and a microprocessor are arranged inside the instrument main body (1); the ultrasonic probes (5) are electrically connected to the AD circuit; the AD circuit is electrically connected to the microprocessor; and the microprocessor is electrically connected to the display screen (2).

2. The acoustic rotor rubbing detection instrument according to claim 1, characterized in that: The ultrasonic probe (5) is a magnetic probe.

3. The acoustic rotor rubbing detection instrument according to claim 2, characterized in that: The ultrasonic probe (5) comprises a probe body, and a magnetic suction seat (52) is provided at the front end of the probe body.

4. The acoustic rotor rubbing detection instrument according to claim 3, characterized in that: A first warning light (51) is provided at the rear end of the probe body.

5. The acoustic-based rotor rubbing detection instrument according to claim 1, characterized in that: It also comprises a wireless sound and light alarm (6), wherein a wireless signal transmitter is arranged inside the instrument main body (1), a wireless signal receiver is arranged inside the wireless sound and light alarm (6), and the wireless sound and light alarm (6) is electrically connected to the instrument main body (1).

6. The acoustic rotor rubbing detection instrument according to claim 5, characterized in that: A second warning light (61) is arranged in front of the wireless sound and light alarm (6).

7. The acoustic rotor rubbing detection instrument according to claim 5, characterized in that: A second alarm speaker (62) is arranged in front of the wireless sound and light alarm (6).

8. The acoustic rotor rubbing detection instrument according to claim 1, characterized in that: A first alarm speaker (3) is arranged in front of the instrument host (1).

9. The acoustic-based rotor rubbing detection instrument according to claim 1, characterized in that: An alarm light (4) is provided in front of the instrument host (1).

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