WO2021033382A1 - 状態監視システムおよび方法 - Google Patents

状態監視システムおよび方法 Download PDF

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Publication number
WO2021033382A1
WO2021033382A1 PCT/JP2020/020145 JP2020020145W WO2021033382A1 WO 2021033382 A1 WO2021033382 A1 WO 2021033382A1 JP 2020020145 W JP2020020145 W JP 2020020145W WO 2021033382 A1 WO2021033382 A1 WO 2021033382A1
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WIPO (PCT)
Prior art keywords
sensor
mechanical seal
condition monitoring
signal
monitoring system
Prior art date
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Ceased
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PCT/JP2020/020145
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English (en)
French (fr)
Japanese (ja)
Inventor
賢治 大津
浩章 長谷川
俊太郎 町田
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Hitachi GE Vernova Nuclear Energy Ltd
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Hitachi-GE Nuclear Energy Ltd
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Publication of WO2021033382A1 publication Critical patent/WO2021033382A1/ja
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
    • F16J15/3296—Arrangements for monitoring the condition or operation of elastic sealings; Arrangements for control of elastic sealings, e.g. of their geometry or stiffness
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M13/00—Testing of machine parts
    • G01M13/005—Sealing rings
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M99/00—Subject matter not provided for in other groups of this subclass

Definitions

  • the present invention relates to a condition monitoring technique for a rotating machine such as a pump having a mechanical seal.
  • Some rotating machines such as pumps have a mechanical seal on the rotating shaft inside the container.
  • the mechanical seal constitutes a sealing mechanism for preventing a liquid (for example, a fluid such as water or oil) in the container from leaking.
  • Rotating machines with mechanical seals are used in various fields such as automobiles, ships, rockets, plants, and housing equipment.
  • the mechanical seal has a rotating ring installed on the rotating shaft side and a stationary ring installed on the container side, and a liquid serving as a sliding surface (in other words, a sealing surface) between the rotating ring and the stationary ring.
  • a film eg, a water film or an oil film
  • Patent Document 1 states that, as a method for diagnosing abnormal sliding of a rotating machine, an AE signal is detected by an AE sensor, and the presence or absence of abnormal sliding and its portion are determined from the frequency having a large amplitude of the frequency distribution. Is described.
  • the abnormality detection or condition monitoring system of the rotating machine of the prior art example detects the AE wave propagating from the mechanical seal via the solid or liquid by the AE sensor installed on the outer wall of the container. Then, this system monitors the effective value in the AE signal from the AE sensor and the number of sudden AE waves generated, and determines that the value is abnormal when the value exceeds a certain threshold value.
  • the determination is made by paying attention to the frequency band such as 0.2 MHz or less as the frequency band of the AE signal. Since the system of the prior art example has the above-mentioned determination method, it cannot be detected as an abnormality until immediately before reaching a state of serious abnormality such as breakage or cracking of the mechanical seal. At the time of detection, it is often too late and the mechanical seal cannot be prevented from being destroyed. It is desirable that it can be detected as a sign of abnormality at an earlier point in time, that is, at a stage where the degree of progress such as abnormality or deterioration is still low.
  • An object of the present invention is to provide a technique for monitoring the state of a rotating machine using AE, which can detect a change in the state of a mechanical seal with high sensitivity and improve the operation and maintenance of the rotating machine.
  • the state monitoring system of one embodiment is a state monitoring system that monitors the state of a rotating machine having a mechanical seal, and receives an AE sensor installed in a container of the rotating machine and an AE signal from the AE sensor. Based on the signal acquisition circuit to be acquired and the information acquired by the signal acquisition circuit, a state including whether or not the mechanical seal is normal is determined, and an alert output or operation control of the rotating machine is performed according to the state.
  • the state monitoring device includes a state monitoring device that performs output control including the above, and the state monitoring device compares the time-frequency response of the frequency spectrum of the AE signal to be monitored with a signal in the past normal time, and sets a predetermined value. The above state is determined based on the determination of the increase in the signal component in the range of 0.7 MHz or more as the frequency range.
  • the state change of the mechanical seal can be detected with high sensitivity, and the operation and maintenance of the rotating machine can be improved.
  • FIG. 5 is a diagram showing a container cross section, an AE sensor installation position, and the like in the first embodiment. It is a figure which shows the structure of the mechanical seal in Embodiment 1.
  • FIG. It is a figure which shows the propagation path of the AE wave in Embodiment 1.
  • FIG. shows the structural example of the AE sensor unit and the jig in Embodiment 1.
  • FIG. FIG. 5 is a diagram showing a configuration example of a signal acquisition unit and the like in the first embodiment. It is a figure which shows the signal example of the AE wave in Embodiment 1.
  • FIG. It is a figure which shows the example of the spectrogram of the AE signal in Embodiment 1.
  • FIG. It is a figure which shows the example of the frequency spectrum of the AE signal in Embodiment 1. It is a figure which shows the state determination example in Embodiment 1. It is a figure which shows the setting example of another frequency range in Embodiment 1. It is a figure which shows the state of the sliding surface, etc. in Embodiment 1.
  • FIG. It is a figure which shows the example of the display screen in Embodiment 1.
  • FIG. It is a figure which shows the container cross section, etc. in the modification 1 of Embodiment 1.
  • the condition monitoring system of the first embodiment is a system that monitors the condition of the rotating machine, particularly the mechanical seal, detects signs of abnormality, and takes countermeasures.
  • the condition monitoring method of the first embodiment is a method having steps executed in the condition monitoring system of the first embodiment.
  • the condition monitoring system of the first embodiment monitors the condition in real time as the rotating machine operates, and when it detects a state of a sign of abnormality of the mechanical seal, it performs output control such as alert output and operation control.
  • a pump will be described as an example of a rotating machine having a mechanical seal, but the present invention can be applied to other rotating machines.
  • the condition monitoring system of the first embodiment utilizes the phenomenon that the frequency band of the AE signal changes, particularly the phenomenon that the frequency spectrum of the high frequency band increases when an abnormality is predicted or occurs in the mechanical seal, and is early. Judgment and detection of abnormal signs.
  • this condition monitoring system focuses on a signal component in a predetermined high frequency range (for example, 0.7 MHz or more) in the frequency band of the AE signal to determine the state.
  • This condition monitoring system monitors time-series changes in the frequency spectrum based on the AE signal detected by the AE sensor installed on the outer wall of the container.
  • This condition monitoring system compares the AE signal to be monitored in real time with the AE signal in the past normal time, and increases the signal component in the set predetermined frequency range (for example, 0.7 MHz or more and 2 MHz or less). to decide. As a result, this condition monitoring system determines and detects at least a normal status (a sign of abnormality or corresponding to an abnormality), and controls output according to the detected status.
  • a normal status a sign of abnormality or corresponding to an abnormality
  • FIG. 1 shows the configuration of the condition monitoring system of the first embodiment.
  • This condition monitoring system is roughly classified into a rotary machine 1 and a condition monitoring device 10, and they are connected via an electric circuit or communication.
  • This condition monitoring system includes a rotating machine 1, a state monitoring device 10, a preamplifier 70, a signal processing circuit (signal processing device) 71, an oscilloscope 72, a rotating power source 31, a rotating machine control device 30, and the like.
  • the user involved in the state monitoring operates the state monitoring device 10.
  • the X, Y, Z, and C directions are shown as the directions.
  • the Z direction is the extending direction of the rotating shaft 3 of the rotating machine 1.
  • the X direction and the Y direction are two directions forming a plane perpendicular to the direction of the rotation axis 3, in other words, the radial direction.
  • the X direction corresponds to the radial direction in which the AE sensor 5 is installed.
  • the C direction is a rotation direction and a circumferential direction.
  • the container 2, the mechanical seal 4, and the like generally have an axisymmetric shape with respect to the rotation axis 3, and are schematically shown as a cylindrical shape, a disk shape, or an annular shape in FIG.
  • the rotating machine 1 has a container 2, a rotating shaft 3, a mechanical seal 4, and the like.
  • the container 2 which is a housing is filled with a liquid.
  • a rotary power source 31 is connected to the rotary shaft 3 outside the container 2.
  • a rotary machine control device 30 is connected to the rotary power source 31.
  • the rotary machine control device 30 controls the operation of the rotary machine 1.
  • the rotary machine control device 30 gives a drive control signal to the rotary power source 31.
  • the rotational power source 31 rotates the rotary shaft 3 in the C direction at a predetermined rotation speed or the like according to the drive control signal.
  • the mechanical seal 4 has a stationary ring 41 fixed to the container 2 side and a rotating ring 42 fixed to the rotating shaft 3 side. With the rotation of the rotating shaft 3, the rotating ring 42 rotates with respect to the stationary ring 41.
  • the AE sensor 5 is fixed in the form of the AE sensor unit 50 to a part of the container 2, for example, one place on the side surface of the outer wall via a jig 6.
  • the AE sensor 5 detects an AE wave generated mainly by using the mechanical seal 4 as a sound source when the rotating machine 1 is in operation, and outputs it as an AE signal.
  • a preamplifier 70 is connected to the AE sensor 5 through a cable.
  • a signal processing circuit 71 is connected to the preamplifier 70 through a cable.
  • An oscilloscope 72 is connected to the signal processing circuit 71 through a cable.
  • the oscilloscope 72 is connected to the condition monitoring device 10 through a cable.
  • the preamplifier 70, the signal processing circuit 71, and the oscilloscope 72 are components for acquiring and processing the AE signal, and correspond to the configuration example of FIG. 6 described later.
  • the latter stage from the signal processing circuit 71 is not limited to wired communication using a cable, but may be wireless communication.
  • the state monitoring device 10 is a device having a state monitoring function for monitoring the state of the rotating machine 1.
  • the condition monitoring device 10 can be configured by, for example, a computer such as a PC or a server, an electronic circuit board, or the like.
  • the condition monitoring device 10 includes a processor 101, a memory 102, a connection interface unit 103, an input device 104, a display device 105, a speaker 106, a lamp 107, and the like, and these are connected to each other via a bus or the like.
  • the processor 101 is composed of a CPU, a ROM, a RAM, and the like, and constitutes a controller for a state monitoring function.
  • the processor 101 realizes a state monitoring function by executing a process according to the control program 111.
  • the memory 102 is composed of a non-volatile storage device or the like, and stores various data and information handled by the processor 101 or the like.
  • the memory 102 stores AE signal data, setting information 121, and the like.
  • the setting information 121 includes system setting information and user setting information related to the state monitoring function.
  • the connection interface unit 103 is an interface portion for connecting an input device 104 or the like, a communication interface device (not shown), or the like.
  • the input device 104 is a device such as an operation panel, a button, or a keyboard that accepts a user's input operation.
  • the display device 105 is a device that displays information and images on a display screen to the user.
  • the speaker 106 is a voice output device that outputs voices such as guides and alarms.
  • the lamp 107 is a device that emits light in response to a guide, an alarm, or the like.
  • condition monitoring device 10 may be connected to the rotary machine control device 30 by communication for output control.
  • condition monitoring device 10 transmits motion control information to the rotary machine control device 30 when the motion control of the rotary machine 1 is performed as output control.
  • the rotary machine control device 30 controls the operation of the rotary machine 1 based on the motion control information.
  • condition monitoring device 10 and the rotary machine control device 30 are configured as separate devices, but the present invention is not limited to this, and in another embodiment, the rotary machine control device 30 is in a state.
  • the function of the monitoring device 10 may be implemented.
  • the function of the signal processing device 71 or the oscilloscope 72 may be mounted on the condition monitoring device 10.
  • the condition monitoring device 10 may be divided into a plurality of devices. Another computer, storage device, communication device, or the like may be connected to the condition monitoring device 10.
  • FIG. 2 shows a schematic view of a cross section (corresponding to the XX plane) of the container 2 on the rotating shaft 3 in the configuration example of the rotating machine 1.
  • This configuration example is the case of the rotary machine 1 having the mechanical seal 4 in one stage in the container 2.
  • FIG. 2 also shows an example of the installation position of the AE sensor 5 with respect to the container 2.
  • the AE sensor 5 is installed at the position Z1.
  • the AE sensor 5 is installed at position Z2.
  • the container 2 is made of, for example, stainless steel as the main material.
  • the cross section of the container 2 has a solid portion 21 and a liquid portion 22.
  • the liquid portion 22 is filled with a liquid (for example, water or oil).
  • the liquid portion 22 has a lower liquid portion 22A and an upper liquid portion 22B as a portion divided by the mechanical seal 4.
  • the liquid part 22A and the liquid part 22B each have a pressure due to the liquid.
  • the container 2 has an inflow port 201 communicating with the liquid portion 22A on a part of the side surface of the outer wall, and an outflow outlet 202 communicating with the liquid portion 22B on the other part of the side surface.
  • the container 2 may include a decompression device 200.
  • the decompression mechanism by the decompression device 200 is a mechanism that decompresses by pressure loss using, for example, a thin tube or an orifice.
  • the depressurizing device 200 adjusts the pressure of the liquid unit 22A by depressurizing according to the control from the rotary machine control device 30.
  • the decompression device 200 is provided at a position leading to the liquid portion 22A.
  • the other part of the side surface has an outlet 203 leading to the decompression device 200. In the vicinity of the rotating shaft 3 at the lower part of the container 2, there is an outflow port 204 leading to the liquid portion 22A.
  • FIG. 3 shows an outline of the configuration of the mechanical seal 4.
  • a rotating ring 42 is fixed at one position in the Z direction with respect to the rotating shaft 3.
  • a stationary ring 41 on the container 2 side is arranged on the upper side of the rotating ring 42.
  • the stationary ring 41 is made of carbon and the rotating ring 42 is made of silicon carbide (SiC) as constituent materials. This combination of materials is commonly used.
  • the combination of materials of the mechanical seal 4 is not limited to this example and can be applied.
  • the rotating ring 42 rotates integrally with the rotation of the rotating shaft 3, whereas the stationary ring 41 is stationary without rotating. At this time, the lower surface of the stationary ring 41 and the upper surface of the rotating ring 42 are close to each other with a gap having a small thickness, and the liquid film 43 is formed.
  • the liquid film 43 is a sliding surface that is a sealing surface.
  • the space between the two liquid portions 22 (22A, 22B) in FIG. 2 is sealed via the liquid film 43 of the mechanical seal 4. Friction due to the viscosity of the liquid in the liquid film 43 of the mechanical seal 4 serves as a sound source and generates an AE wave.
  • one AE sensor 5 is installed on the side surface of the outer wall of the container 2.
  • one AE sensor 5 is installed at one of the outer peripheral surfaces in the C direction on the side surface of the substantially cylindrical container 2.
  • the AE sensor 5 is attached to the side surface of the container 2 in the form of the AE sensor unit 50 and with the jig 6 interposed therebetween, for example, as shown in FIG. 1 and FIG. 5 described later.
  • a capplant 8 as an acoustic transmission medium is interposed between the receiving surface of the AE sensor 5 and the outer surface of the container 2.
  • the material of the couplant 8 is grease, wax, an adhesive or the like.
  • the function of the coplant 8 is to prevent the reflection of sound waves and facilitate the transmission of AE waves to the receiving surface of the AE sensor 5.
  • Ultrasonic waves which are high-frequency sound waves, are almost totally reflected at the interface with air. Therefore, the gap between the container 2 and the wave receiving surface of the AE sensor 5 is filled with the coplant 8 so that air and minute bubbles do not enter and are brought into close contact with each other.
  • FIG. 4 shows an outline of the propagation path of the AE wave corresponding to the configuration example of FIG.
  • two propagation routes are shown as the main propagation routes.
  • (A) is a path mainly passing through the solid portion 21 as the first propagation path, and corresponds to the propagation path P1 in FIG.
  • (B) is a path passing through the solid part 21 and the liquid part 22 as the second propagation path, and corresponds to the propagation path P2 in FIG.
  • an AE wave is generated from the mechanical seal 4, which is a sound source, as it slides.
  • the propagation path of (A) is a path from the mechanical seal 4 to the receiving surface of the AE sensor 5 via the solid portion 21 of the container 2 and the coplant 8 on the outer surface.
  • the propagation path of (B) is a path from the mechanical seal 4 to the solid part 21 via the liquid part 22 of the container 2, and from the solid part 21 to the receiving surface of the AE sensor 5 via the outer surface of the coplant 8.
  • a jig 6 or a holder 501 (particularly the flange portion 502 in FIG. 5) of the AE sensor unit 50 is interposed between the coplant 8 and the AE sensor 5. To do.
  • the AE sensor 5 is installed on the side surface of the container 2 at the position Z1 corresponding to the propagation path P1.
  • This position Z1 is a position close to the height position of the mechanical seal 4 in the Z direction.
  • the propagation path P1 is a path in which the propagation distance is the smallest among the paths in which the AE wave from the mechanical seal 4 propagates to the outer wall as a direct wave via the solid portion 21.
  • the position Z1 is a suitable position selected in correspondence with the propagation path P1. As a result, the AE sensor 5 can detect the AE wave with the highest sensitivity.
  • the propagation path from the mechanical seal 4 to the AE sensor 5 is preferably not mediated by air, and is more preferably a path that does not pass through the liquid portion 22 as much as possible, such as the first propagation path.
  • the acoustic impedance is a constant peculiar to a substance, and MRail (mega rail) is generally used as a unit.
  • 1M Rayl 1 ⁇ 10 6 kg ⁇ m -2 ⁇ s -1 .
  • ⁇ represents the density of the acoustic medium and C represents the speed of sound in the acoustic medium.
  • the acoustic impedance (unit [MRayl]) of a typical substance is 0.00041 for air, 1.5 for water, 3.1 for acrylic, 5.0 for carbon, 16.9 for aluminum, 34.6 for SiC, 40.6 for piezoelectric ceramic, and 45.8 for stainless steel. Since the acoustic impedance of air is very small, if bubbles are present in the propagation path of the AE wave, which is an ultrasonic wave, the ultrasonic wave is totally reflected at the boundary.
  • a coplant 8 is used to bring the container 2 into close contact with the wave receiving surface of the AE sensor 5 so that microbubbles do not intervene.
  • the first propagation path of (A) in FIG. 4 is, for example, carbon ⁇ stainless steel ⁇ piezoelectric ceramic.
  • the transmission loss at the interface between carbon and stainless steel is about 4.5 dB
  • the transmission loss at the interface between stainless steel and piezoelectric ceramic is about 0.01 dB. From this, at least 4.5 dB of the AE wave is attenuated by reflection from the sound source to the receiving surface of the AE sensor 5.
  • the second propagation path via the liquid portion 22 of FIG. 4B is, for example, carbon ⁇ water ⁇ stainless steel ⁇ piezoelectric ceramic.
  • the permeation loss at the interface between carbon and water is about 1.5 dB
  • the permeation loss at the interface between water and stainless steel is about 9.2 dB
  • the permeation loss at the interface between stainless steel and piezoelectric ceramic is about 0.01 dB.
  • the AE wave is attenuated by at least 10.7 dB due to reflection between the media. That is, in the second propagation path, the signal strength is attenuated to 1/3 or less.
  • the path propagating between solid materials can detect AE waves with smaller reflection at the interface and higher intensity than the path propagating through the liquid. Therefore, in the first embodiment, the AE sensor 5 is installed at a position (position Z1) corresponding to the first propagation path of FIG. 4 (propagation path P1 of FIG. 2).
  • the installation position of the AE sensor 5 in FIG. 2 is one place on the outer circumference of the container 2.
  • the outer circumference of the container 2 is a curved surface
  • the receiving surface of the AE sensor 5 is generally a flat surface. Therefore, the jig 6 for conversion as shown in FIG. 5 is used so that the receiving surface of the AE sensor 5 can be installed as a flat surface with respect to the curved surface.
  • a part of the curved surface such as the side surface of the container 2 may be cut so as to be a flat surface, and the receiving surface of the AE sensor 5 may be installed on the flat surface.
  • FIG. 5 shows a configuration example of the AE sensor unit 50 and the jig 6 attached to the outer wall of the container 2.
  • FIG. 5 shows a schematic view of a cross section (corresponding to the XX plane).
  • the side surface 2S of the outer wall of the container 2 has a convex curved surface.
  • the AE sensor 5 is configured as an AE sensor unit 50 by being housed in a holder (in other words, a cover) 501.
  • the holder 501 and the jig 6 have a mechanism for stable fixing of the AE sensor 5 to the surface of the container 2.
  • the jig 6 is an installation tool for conversion and interconnection between the curved surface of the side surface 2S of the container 2 and the flat surface 52S which is the receiving surface of the receiving plate 52 of the AE sensor 5.
  • the jig 6 has a concave curved surface 61 on one surface facing the container 2 and a flat surface 62 on the other surface facing the AE sensor 5.
  • a couplant 8 (for example, an adhesive) is filled and adhered between the curved surface of the side surface 2S of the container 2 and the curved surface 61 of the jig 6.
  • a coplant for example, an adhesive
  • the flat surface 52S or the flat surface of the flange portion 502 which is the receiving surface of the AE sensor 5 and the flat surface 62 of the jig 6, or the screw 503 as in this example. Etc. are fixed.
  • the material of the jig 6 is preferably a material whose acoustic impedance is close to the acoustic impedance of the container 2, and for example, stainless steel is used.
  • the flat surface of the flange portion 502 of the holder 501 is fixed to the flat surface 62 of the jig 6 by a plurality of screws 503.
  • the AE sensor 5 is housed in the holder 501.
  • the shield case 54 of the AE sensor 5 is pushed by the spring 504, so that the receiving surface of the receiving plate 52 of the AE sensor 5 is in close contact with the flat surface of the flange portion 502.
  • the wave receiving plate 52 may be brought into close contact with the flat surface of the flange portion 502 by, for example, an adhesive.
  • the means for fixing the members to each other is not limited to screws, adhesives and springs, and can be applied.
  • the holder 501 has, for example, a box shape, but may have a columnar shape or another shape.
  • the flat plate of the flange portion 502 has, for example, a quadrangle when viewed in a plan view in the X direction, which is a direction perpendicular to the installation surface, but the flat plate may be not limited to this and may be circular or the like.
  • the holder 501 is a cover having waterproof and oil-proof properties. As another embodiment, when the AE sensor 5 having waterproof property, oil resistance, etc. is applied, the holder 501 or the like may be omitted.
  • the types of the AE sensor 5 are wideband type and single-ended type.
  • This wideband type includes a flat band as a frequency characteristic, and has a wide band of, for example, 100 kHz to 4 MHz.
  • the AE sensor 5 includes a piezoelectric element 51, a wave receiving plate 52, a damper 53, a shield case 54 (including a lid), a connector 55, a signal cable 56, and the like.
  • the AE sensor 5 has, for example, a wave receiving plate 52 on the bottom surface of the cylindrical shield case 54, and a piezoelectric element 51 and a damper 53 on the wave receiving plate 52 in the shield case.
  • the outer surface of the shield case 54 is covered with Kapton tape 505.
  • the piezoelectric element 51 is composed of piezoelectric ceramics, converts an AE wave propagating on the receiving plate 52 into an electric signal by the piezoelectric effect, and outputs the AE wave from the signal cable 56.
  • the AE sensor 5 suppresses resonance by a damper 53 that covers the piezoelectric element 51 on the receiving plate 52.
  • the signal cable 56 from the piezoelectric element 51 is connected to the connector 55, and is connected to an external cable through the connector 55.
  • the sensitivity of the AE sensor 5 is, for example, 40 to 55 dB.
  • FIG. 6 shows a circuit configuration example of the preamplifier 70, the signal processing device 71, the oscilloscope 72, the condition monitoring device 10, and the like. It is applicable not only to the circuit configuration example of FIG.
  • This circuit configuration example is roughly divided into a signal acquisition unit 600 that acquires an AE signal from the AE sensor 5 and prepares it into a suitable signal, and processing such as analysis, determination, and output control of the signal acquired by the signal acquisition unit 600. It has a state monitoring device 10 for performing the above.
  • the signal acquisition unit 600 includes a preamplifier 70, a signal processing device 71, and an oscilloscope 72.
  • the signal processing device 71 includes a bandpass filter (BPF) 71A and a main amplifier 71B.
  • BPF bandpass filter
  • the oscilloscope 72 includes an analog-to-digital converter (ADC) 72A, a display 72B, and a storage unit 72C.
  • the condition monitoring device 10 includes a frequency analysis unit 10A as a signal calculation unit 601, a state determination unit 10B, an output control unit 10C, a normal signal storage unit 10D, and a condition setting unit 10E.
  • Each part of the condition monitoring device 10 may be realized by, for example, program processing by the processor 101 based on the configuration of FIG. 1, or may be realized by the circuit which implemented the function of each part.
  • the AE signal output from the AE sensor 5 is minute, it is amplified by an amplifier and used.
  • the amplifier often uses a two-stage configuration consisting of a preamplifier and a main amplifier.
  • the preamplifier 70 and the main amplifier 71B in the signal processing circuit 71 are used.
  • the amplification of the AE signal is, for example, 40 dB for the preamplifier 70 and 20 dB for the main amplifier 71B, for a total of 60 dB.
  • the AE signal from the AE sensor 5 is input to the preamplifier 70 and amplified, and the amplified AE signal is input to the BPF71A of the signal processing circuit 71. Since noise is easily picked up between the AE sensor 2 and the preamplifier 70, the cable length is shortened and a low noise cable is used.
  • the signal processing circuit 71 is configured as, for example, one device.
  • the BPF71A has a function of a high-pass filter and a low-pass filter.
  • the BPF71A extracts the high frequency component of the AE signal by using the high-pass filter function.
  • the cutoff frequency of the high-pass filter is set to 100 kHz, and vibration components and the like in a frequency band lower than the AE frequency due to plastic deformation of the mechanical seal 4 are cut.
  • the low-pass filter function is not used as a through state.
  • the main amplifier 71B further amplifies the signal from the BPF 71A.
  • the oscilloscope 72 is a waveform measuring instrument.
  • the oscilloscope 72 and the signal processing circuit 71 may be configured as an integrated device.
  • the ADC 72A converts the AE signal, which is an analog signal from the main amplifier 71B, into a digital signal.
  • the ADC72A used a digital oscilloscope, and in this example, the sampling frequency was set to 5 MHz.
  • the digital signal of the AE signal from the ADC 72A is displayed on the monitor on the display screen of the display 72B and is stored as raw data in the storage unit 72C (for example, a hard disk drive).
  • the display 72B is a waveform display, and displays a state such as an amplitude of an AE wave of an AE signal.
  • the storage unit 72C stores the raw data of the AE signal as a log. The user can output data from the storage unit 72C based on the operation.
  • the AE signal data from the ADC 72A is input to the condition monitoring device 10 through the connection interface unit 103.
  • the frequency analysis unit 10A of the signal calculation unit 601 performs frequency analysis in real time on the AE signal to be monitored. As a result, the frequency analysis unit 10A calculates a time-frequency response (also referred to as a spectrogram) representing a time-series change in the frequency spectrum, which is the frequency response of the AE signal.
  • the frequency analysis unit 10A outputs the monitoring target signal SIG1 including the calculated spectrogram to the state determination unit 10B.
  • the state determination unit 10B pays attention to the component of the set predetermined frequency range H1 in the spectrogram of the monitoring target signal SIG1, and detects the change based on the comparison with the past normal signal SIG2, thereby mechanically sealing 4 Judge the state of.
  • the frequency range H1 is 0.7 MHz or more and 2.0 MHz or less.
  • the state determination unit 10B determines the state based on a predetermined condition including the predetermined frequency range H1.
  • the state determination unit 10B compares the spectrogram of the frequency range H1 of the monitored signal SIG1 with the spectrogram of the frequency range H1 of the normal signal SIG2, and extracts, for example, the difference regarding the component of the frequency range H1.
  • the state determination unit 10B is in an abnormal state (no state) when, for example, as a change in the signal component in the frequency range H1, the above difference exists to some extent or more, for example, increases by a predetermined rate or more. ), That is, it is judged as a state such as an abnormality sign.
  • the state determination unit 10B outputs a determination result signal SIG3 indicating the state of the determination result to the output control unit 10C.
  • the spectrogram information in the monitored signal SIG1 is measured and stored for each predetermined time unit and for each predetermined frequency section (for example, 100 kHz unit).
  • the state determination unit 10B refers to the data for each time unit and each frequency section in the frequency range H1, and when there is an increase of a certain amount or more in the entire frequency range H1 as compared with the corresponding data of the normal signal SIG2. , It is judged as a negative state. Alternatively, the state determination unit 10B determines that the state is negative when there is an increase of a certain amount or more in an arbitrary part of the frequency range H1.
  • the normal signal storage unit 10D stores past normal AE signal data for comparison.
  • This normal signal SIG2 is a spectrogram of data actually measured in the past, and is data determined to be in a normal state. Based on the determination result in the state determination unit 10B, the AE signal data in the normal state may be stored in the normal signal storage unit 10D as the normal signal SIG2 at regular intervals. Alternatively, depending on the user's setting, specific data at the normal time may be stored in the normal signal storage unit 10D as the normal signal SIG2.
  • the condition monitoring device 10 stores information such as the date and time of monitoring, the ID of the target rotating machine 1 and the AE sensor 5, as well as the AE signal data.
  • a predetermined condition including a predetermined frequency range H1 is set in the condition setting unit 10E, and the condition is set in the state determination unit 10B.
  • This condition may include a rate or the like for determining the degree of the above change. The user can confirm and set this condition on the display screen described later.
  • the predetermined frequency range H1 can be a range of 0.5 MHz or more (for example, a range of 0.5 MHz or more and 5.0 MHz or less) as the widest range.
  • the frequency range H1 is set as a narrower range of 0.7 MHz or more and 2.0 MHz or less.
  • the frequency range H1 may be set as a range of 1.0 MHz or more and 2.0 MHz or less as a narrower range.
  • the suitable frequency range H1 is determined according to the material of the mechanical seal 4. When the mechanical seal 4 is made of another material different from the above-mentioned material, the frequency range H1 is set to another frequency range according to the material.
  • the state determination unit 10B may perform state determination using machine learning or deep learning. Further, the state determination unit 10B is not limited to the binary determination of whether or not it is normal, and may classify from normal to abnormal into a plurality of degrees and determine a plurality of states. For example, when the change of the signal component in the frequency range H1 is less than the first rate, it is regarded as a normal state, and when it is more than the first rate and less than the second rate, it is regarded as an abnormal sign state, and the second rate or more. In some cases, it may be in an abnormal state.
  • the output control unit 10C has a function of performing alert output 91, operation control 92, monitor display 93, and the like.
  • the output control unit 10C executes output control corresponding to the negative state.
  • the output control unit 10C immediately outputs, for example, an alert indicating an abnormality sign to the user as an alert output 91.
  • the alert output 91 include an alert voice output from the speaker 106 of FIG. 2, an alert light emission of the lamp 107, an alert information display on the display screen of the display device 105, a notification through a communication interface, and the like.
  • the alert output 91 may be provided with a plurality of levels of alerts according to the degree of abnormality.
  • the operation control 92 is to control the operation of the rotating machine 1, and examples thereof include control for immediately stopping the operation (operation stop control) and control for slowing down the operation (operation deceleration control). ..
  • the operation stop control includes, for example, stopping the rotation of the rotating shaft 3.
  • the operation stop control can be applied to the case of the rotary machine 1 in which there is no problem even if the operation is stopped.
  • the operation deceleration control may, for example, reduce the rotation speed of the rotating shaft 3.
  • the output control unit 10C may perform feedback control so as to increase or decrease the rotation speed of the outer circumference of the rotation shaft 3 according to the state at each time point, for example. Thereby, the sliding surface of the mechanical seal 4 can be adjusted.
  • Another operation control 92 includes a control that controls the decompression device 200 of FIG. 2 to adjust the pressure (pressure difference of the surface pressure received by the rotating shaft 3 and the mechanical seal 4). At the time of operation control, the cooperation with the rotary machine control device 30 is performed as described above.
  • the monitor display 93 may display the spectrogram of the monitoring target signal SIG1 and the information of the determination result on the display screen of the display device 105 of FIG. From the output of the output control unit 10C, the user can recognize the state of the mechanical seal 4 of the rotary machine 1 as a sign of abnormality before a serious abnormality such as damage occurs, and can deal with it.
  • FIG. 7 shows an example of the signal shape of the AE wave.
  • (A) and (B) show typical signal shape examples of the AE wave generated by the sliding of the mechanical seal 4 as shown in FIG. (A) is an example of an AE wave in a normal state.
  • This AE wave has a shape called a continuous AE wave.
  • the mechanical seal 4 slides the AE signal of such a continuous AE wave is always excited.
  • Such continuous AE waves cannot be time-correlated. Therefore, as an example of the prior art, it is difficult to install a plurality of AE sensors at spatially separated positions and to position the sound source from the time difference in which the AE waves reach the AE sensors.
  • (B) is an example of an AE wave at the time of an abnormality sign, and shows an example in which a sudden side AE wave (for example, a sudden side AE wave 701) overlaps with a continuous type AE wave.
  • a sudden side AE wave for example, a sudden side AE wave 701
  • a foreign substance for example, abrasion powder
  • a sudden AE wave is generated. It is difficult to detect the generation of a sudden AE wave unless the amplitude of the sudden AE wave is sufficiently larger than the amplitude of the continuous AE wave.
  • FIG. 8 shows an example of a spectrogram which is a time-frequency response of an AE wave of an AE signal when changing from a normal state to an abnormal state via an abnormal sign state when an abnormality occurs.
  • the horizontal axis of the graph is time, and the vertical axis is frequency [MHz].
  • the AE signal strength [dB] at each point is represented by the gray scale of the color map.
  • the intensity range was from -50 dB to -35 dB, -50 dB was black, and -35 dB was white.
  • This AE signal data is data measured with a sampling frequency of 5 MHz. Therefore, the frequency range of the graph is in the range of 0 to 2.5 MHz.
  • Time TA is normal time
  • time TB is an abnormal sign time.
  • an AE signal having a frequency component of 0.7 MHz or less is continuously detected during sliding.
  • the signal component in the frequency band above 0.7 MHz is small.
  • white values are mainly distributed within the range of 0.7 MHz or less.
  • the signal strength of the signal component in the frequency band of 0.7 MHz or more and 2.0 MHz or less is increased in addition to the signal component of 0.7 MHz or less.
  • white values appear and are distributed even within the range of 0.7 MHz or more and 2.0 MHz or less.
  • the signal strength of 2.0 to 2.5 MHz at the time of an abnormality sign is relatively small and appears black.
  • This is the broadband AE sensor used in the measurement of this example. This is because the sensitivity is lowered at 2.0 MHz or higher due to the influence of the frequency characteristic of 5.
  • an AE sensor 5 that easily detects a signal component of 0.5 to 2.0 MHz is used.
  • the frequency band of the AE signal at the time of an abnormality sign exists in the range of 2.0 MHz or more, for example, up to 5 MHz.
  • the predetermined frequency range H1 to be focused on at the time of the conventional determination is set to a range of 0.7 MHz or more, for example, a range of 0.7 MHz or more and 2.0 MHz or less, as shown in the figure.
  • the lower limit of the frequency range H1 is set to 0.7 MHz.
  • the lower limit value may be 0.5 MHz or 1 MHz.
  • the upper limit of the frequency range H1 can be acquired up to, for example, 5.0 MHz, but in this example, the upper limit of the frequency range H1 is set to 2.0 MHz in consideration of the characteristics of the AE sensor 5 and the processing efficiency in real time. ..
  • the state determination unit 10B can determine the abnormality sign state by comparing the spectrogram of the monitored signal SIG1 with the normal signal SIG2 and determining an increase in the signal component in the frequency range H1.
  • the state determination unit 10B can detect, for example, an abnormality sign state when the component in the frequency range H1 increases to some extent, for example, by a predetermined rate or more at the time of time TB.
  • the frequency band of such an AE signal mainly depends on the material of the mechanical seal 4. That is, the frequency range H1 is set corresponding to the combination of materials of the mechanical seal 4. Specifically, the frequency band of the AE signal varies depending on the sliding conditions such as the size, shape, rotation speed, load, etc. of the rotating machine 1 including the mechanical seal 4, but the material of the mechanical seal 4 is the most dominant. .. Even if the details of the sliding conditions are changed, it is possible to detect an abnormal sign at an early stage by paying attention to the change of the signal component in the frequency range H1.
  • FIG. 9 shows a frequency spectrum which is a frequency characteristic at time TA and time TB of FIG.
  • the characteristic 1001 shown by the thick line is the frequency spectrum of the time TA in the normal state, and corresponds to the cross section of the broken line of the time TA in FIG.
  • the characteristic 1002 shown by the thin line is the frequency spectrum in the abnormal sign state of the time TB, and corresponds to the cross section of the broken line of the time TB.
  • the horizontal axis of the graph is the frequency [MHz], and here, the range from 0.5 MHz to 2.5 MHz is shown.
  • the vertical axis represents the AE signal strength [dB].
  • the threshold value selected so that the signal intensity distribution is displayed by the white value in FIG. 8 was set to -45 dB as the threshold value 1003 in FIG.
  • the condition is that the signal strength is -45 dB or more (or greater than -45 dB).
  • the time TA characteristic 1001 corresponds to the portion where the frequency is approximately 0.6 MHz or less
  • the time TB characteristic 1002 indicates that the frequency is approximately 1.9 MHz or less.
  • the part that becomes is applicable.
  • focusing on the signal component having a frequency of 0.7 MHz or more the difference between the normal time and the abnormal sign time is clear. It can be seen that the AE signal strength is large over the high frequency band corresponding to the frequency range H1 at the time of an abnormality sign.
  • the state determination unit 10B determines the state by utilizing such characteristics.
  • FIG. 10 schematically shows an example of state determination by the state determination unit 10B.
  • (A) is the first example.
  • the state determination unit 10B pays attention to the signal component of the entire frequency range H1, and the signal component of the entire frequency range H1 of the characteristic 1102 of the monitored signal SIG1 is the signal component of the entire frequency range H1 of the characteristic 1101 of the normal signal SIG2. , If it increases at a predetermined rate (for example, rate R1) or more, it is determined to be an abnormal sign state.
  • This rate is a threshold for determining the rate and magnitude of the increase.
  • the state determination unit 10B calculates the difference (for example, the sum of the differences for each frequency section) for the signal components of the entire frequency range H1 by comparing the characteristic 1102 of the monitored signal SIG1 with the characteristic 1101 of the normal signal SIG2. To do. When the difference is equal to or larger than a predetermined size, the state determination unit 10B determines that the state is an abnormal sign state.
  • the state determination unit 10B also determines that the abnormality sign state is obtained even when only an arbitrary part of the signal components in the frequency range H1 increases.
  • the signal component of a part (for example, range 1105) of the frequency range H1 in the characteristic 1102 of the monitored signal SIG1 is the corresponding one of the frequency range H1 of the characteristic 1101 of the normal signal SIG2.
  • rate R1 and the rate R2 may be different.
  • the state determination unit 10B calculates, for example, the difference in the signal component for each frequency section in the frequency range H1 by comparing the characteristic 1102 of the monitored signal SIG1 with the characteristic 1101 of the normal signal SIG2. When the difference in at least a part of the frequency sections is equal to or larger than a predetermined size, the state determination unit 10B determines that the state is an abnormal sign state. In addition, a different rate R2 may be set for each divided portion in the frequency range H1.
  • FIG. 11 shows another example relating to the setting of the frequency range H1 as a modification.
  • the frequency range H1 is a range of 1 MHz or more, for example, a range of 1 MHz or more and 2.0 MHz or less.
  • A shows the spectrogram of the AE signal which is different from FIG.
  • the frequency range H1b is a range of 1 MHz or more and 2 MHz or less.
  • B shows the frequency spectrum corresponding to (A).
  • the signal strength is high. In particular, the signal strength is large in the range of 1 MHz or more and 2 MHz or less. Even when the frequency range H1b is set like this, an abnormality sign can be detected.
  • FIG. 12 shows the normal and abnormal states of the sliding surface of the mechanical seal 4 and the like, and the dynamics such as general friction.
  • the sliding surface has a liquid film such as a lubricant between the surfaces of the first solid and the second solid.
  • the horizontal axis of the graph is a value calculated as (viscosity ⁇ ⁇ velocity V) / load F N.
  • the vertical axis is the coefficient of friction on the sliding surface, and is f.
  • the interval h is much larger than the surface roughness R and corresponds to the normal state (or steady state).
  • the interval h approaches 0.
  • the mixed lubrication region 1202 is a region between the fluid lubrication region 1201 and the boundary lubrication region 1203, and the interval h is close to the surface roughness R.
  • the mixed lubrication region 1202 and the boundary lubrication region 1203 correspond to the abnormal state.
  • Continuous dynamics act in the fluid lubrication region 1201 and the mixture lubrication region 1202.
  • Contact dynamics act in the mixed lubrication region 1202 and the boundary lubrication region 1203.
  • the friction coefficient f decreases and enters the mixed lubrication region 1202, and as the wear progresses further, the friction coefficient f increases.
  • the above-mentioned AE signal of FIG. 11 is a signal when the sliding surface of the mechanical seal 4 is in the state of the mixed lubrication region 1202 of FIG.
  • the liquid film is thinner than that in the fluid lubrication region 1201, and the stationary ring 41 and the rotating ring 42 come into local contact with each other, causing wear and the like.
  • the signal strength of the AE signal in such a sliding state increases, for example, in the frequency region of 0.7 MHz or higher.
  • the condition monitoring system of the first embodiment can detect the mixed lubrication region 1202, particularly the region 1204 related to the early change, as a state of a sign of abnormality as the state of the sliding surface of the mechanical seal 4.
  • FIG. 13 shows an example of a graphical user interface (GUI) on the display screen provided by the condition monitoring device 10 to the user.
  • the condition monitoring device 10 displays such GUI information on the screen of the display device 105 based on the user's operation.
  • the user can confirm and change the settings on this screen, and can transition to another screen such as the monitor display 93 of the output control unit 10C.
  • the GUI information of FIG. 13 is an example of setting a condition for determining a state, and has a setting name, a frequency range H1, a change (rate), an annotation, and the like as items.
  • the user can select and set the lower limit value and the upper limit value of the frequency range H1 that constitute the condition.
  • the user can select and set a rate [%] regarding the magnitude of change of the monitored signal SIG1 with respect to the normal signal SIG2, which constitutes the condition.
  • the user can describe a comment about the setting in the comment item.
  • the user can change the setting according to the material of the rotating machine 1 to be monitored, the mechanical seal 4, and the like, whereby the sensitivity can be adjusted.
  • the user can also change the position where the AE sensor 5 is installed with respect to the container 2, whereby the sensitivity can be adjusted.
  • FIG. 14 shows a configuration example such as a cross section of the container 2 in the modified example of the first embodiment (referred to as the modified example 1).
  • the first modification at least a part of the outer surface of the outer wall of the container 2 made of stainless steel other than the place where the AE sensor 5 is installed is covered with the sound absorbing material 9.
  • the sound absorbing material 9 absorbs the reflected wave. As a result, sound waves can be released to the sound absorbing material 9 side, the reflection of the liquid portion 22 into water can be reduced, and multiple reflection due to reflection at the interface can be suppressed.
  • the substance of the sound absorbing material 9 is preferably a material having an acoustic impedance close to that of stainless steel, that is, a material having a large specific gravity and a high sound velocity.
  • a material having a large specific gravity and a high sound velocity for example, lead or the like can be applied to the material of the sound absorbing material 9, and for example, a rolled lead plate is used as the sound absorbing material sheet. Further, it is better to fill the space between the outer wall of the container 2 and the sound absorbing material 9 with a couplant so that an air layer is not formed.
  • Modification 2 As a modification 2 of the first embodiment, the following configuration is also possible.
  • the position Z2 is a position on the side surface of the container 2 corresponding to the propagation path P2 in which the AE wave from the mechanical seal 4 propagates through the liquid portion 22.
  • the propagation path P2 is less sensitive than the propagation path P1 because reflection occurs at the interface between the solid and the liquid, but it is also applicable.
  • the AE signal from the AE sensor 5 of the propagation path P2 it is possible to detect an abnormality sign by the determination using the frequency range H1.
  • the shape of the outer wall may be complicated and not suitable for installation, or other parts may be arranged.
  • the AE sensor 5, the jig 6, and the like are installed at the position of the outer wall near the liquid portion 22 of the container 2.
  • the position Z2 in which the AE sensor 5 is installed in FIG. 2 is below the position Z1 and is the outer peripheral position with respect to the liquid portion 22.
  • the propagation path P2 is selected as a propagation path having a propagation distance as small as possible among the propagation paths passing through the liquid portion 22.
  • FIG. 15 shows the cross section of the container 2 and the installation position of the AE sensor 5 in the modified example 3 of the first embodiment.
  • the wave receiving surface of the AE sensor 5 is installed at one place on the upper flat surface of the outer wall of the container 2.
  • the propagation path P1b is a path in which the AE wave from the mechanical seal 4 propagates to the upper surface as a direct wave mainly via the solid portion 21.
  • the installation position X3 of the AE sensor 5 is set to a position closer to the outer circumference as a position slightly separated from the position of the rotating shaft 3 so as to reduce noise related to the rotating shaft 3.
  • a position X3 having relatively little noise related to the rotating shaft 3 is selected, mainly corresponding to the propagation path P1b passing through the solid portion 21.
  • the AE sensor 5 When it is difficult to install the AE sensor 5 on the side surface of the container 2, the AE sensor 5 may be installed on a flat surface such as the upper surface of the container 2 as in the modified example 3. In the case of the modification 3, there is an advantage that the AE sensor 5 can be easily attached to the container 2, and the jig 6 and the like can be omitted or simplified.
  • FIG. 16 shows the installation position and the like of the AE sensor 5 in the modified example 4 of the first embodiment.
  • two or more AE sensors 5 are installed at two or more positions on the outer peripheral surface in the circumferential direction of the outer wall of the container 2.
  • AE sensors 5a and 5b are installed at two locations on the outer circumference of the container 2 facing each other via a jig 6, respectively. Since the container 2 and the mechanical seal 4 have an axisymmetric shape, the AE wave from the sound source reaches each position on the outer circumference. Therefore, basically, if there is one AE sensor 5, the AE wave can be detected. However, in some cases, it is assumed that the AE wave may propagate only to a part of the outer circumference.
  • a plurality of AE sensors 5 are installed on the outer circumference. As a result, at least one AE sensor 5 can detect the AE wave at any time. Similarly, not only on the side surface of the container 2, but also on the upper surface or the like, a plurality of axially symmetric positions may be selected and a plurality of AE sensors may be arranged.
  • FIG. 17 shows the installation position and the like of the AE sensor 5 in the modified example 5 of the first embodiment.
  • the AE sensor 5 is installed inside the container 2.
  • FIG. 17 shows some examples of installation positions.
  • the installation example A is an example in which the AE sensor unit 50 in which the AE sensor 5 is housed is directly installed on the stationary ring 41.
  • Installation example B is an example in which the AE sensor unit 50 is installed at a position of the solid portion 21 facing the liquid portion 22A.
  • Installation example C and installation example D are examples in which the AE sensor unit 50 is installed so as to be embedded in the solid portion 21. Both installation examples are selected as positions that do not come into contact with air on the propagation path of the direct wave from the mechanical seal 4.
  • the cable from the AE sensor 5 penetrates the inside of the container 2 and goes out.
  • the AE sensor 5 by arranging the AE sensor 5 as close to the mechanical seal 4 as the sound source, the influence of the reflection of the ultrasonic wave at the interface between the materials can be reduced, and the propagation attenuation of the ultrasonic wave can be reduced.
  • the sensitivity of detection can be increased.
  • the AE sensor 5 is installed inside the container 2 in this way, it is difficult to take out the AE sensor 5 while the rotating machine 1 is in operation. Therefore, this configuration is disadvantageous in terms of maintenance and the like, and it is difficult to adjust the installation position to increase the sensitivity.
  • the AE sensor 5 in consideration of advantages such as maintenance, the AE sensor 5 is basically installed on the outer surface of the container 2, and the sensitivity is increased as much as possible.
  • the condition monitoring system according to the second embodiment of the present invention will be described with reference to FIG. Hereinafter, the components different from those of the first embodiment in the second embodiment and the like will be described.
  • the condition monitoring system of the second embodiment uses an AE sensor additionally installed in a rotating machine such as a pump to cancel the influence of noise related to the rotating shaft and improve the accuracy of the condition determination.
  • FIG. 18 shows the installation position and the like of the AE sensor 5 in the second embodiment.
  • the second embodiment has AE sensors 5m and 5n as two AE sensors 5 on the outer surface of the container 2.
  • the main AE sensor 5m is installed at one place on the side surface of the container 2
  • the sub AE sensor 5 is installed at one place on the upper surface.
  • the sub AE sensor 5 is used to detect noise related to the rotating shaft 3 and cancel it by subtraction or the like.
  • the AE sensor 5 m is installed at the position Z1 ahead of the propagation path P1 as in the first embodiment.
  • a sub AE sensor 5n is installed at a position Xn near the inner circumference, which is relatively close to the rotation shaft 3.
  • This position Xn is selected as a position for picking up noise related to the rotation axis 3 to some extent among the positions corresponding to the propagation path Pn of the direct wave from the mechanical seal 4.
  • the main AE sensor 5m is selected as a position that does not pick up noise related to the rotating shaft 3 as much as possible.
  • the lower side of FIG. 18 briefly illustrates an example of the circuit configuration according to the second embodiment.
  • the signal acquisition unit 600 of FIG. 6 acquires a first AE signal which is a main AE signal from the main AE sensor 5m and a second AE signal which is a sub AE signal from the sub AE sensor 5n.
  • the second AE signal includes noise of a vibration component on the rotation power source 31 side propagating along the rotation shaft 3 as noise related to the rotation shaft 3.
  • the signal acquisition unit 600 or the condition monitoring device 10 includes a subtractor 181.
  • the subtractor 181 subtracts the second AE signal from the first AE signal. The effect of noise related to the rotating shaft 3 is removed to some extent from the subtracted signal.
  • the state determination unit 10B of the state monitoring device 10 determines the state of the subtracted signal. As a result, in the second embodiment, it is possible to distinguish between the AE wave using the mechanical seal 4 as a sound source and the noise related to the rotation axis 3 which is an external sound source, and more accurate state determination is possible.
  • the condition monitoring system according to the third embodiment of the present invention will be described with reference to FIG.
  • the condition monitoring system of the third embodiment has a configuration in which a rotating machine such as a pump has a plurality of stages of mechanical seals, and monitors the condition of each mechanical seal using a plurality of AE sensors.
  • FIG. 19 shows a cross section of the container 2 of the rotary machine 1 in the third embodiment, installation positions of a plurality of AE sensors 5, and the like.
  • the container 2 has mechanical seals 4A and 4B as two-stage mechanical seals 4 in the Z direction.
  • the lower mechanical seal 4A in the Z direction is referred to as the first mechanical seal (in other words, the first step sliding portion), and the upper mechanical seal 4B in the Z direction is referred to as the second mechanical seal (in other words, the second step sliding portion).
  • the mechanical seal 4A is composed of a pair of a stationary ring 41A which is a first stationary ring and a rotating ring 42A which is a first rotating ring.
  • the mechanical seal 4B is composed of a pair of a stationary ring 41B which is a second stationary ring and a rotating ring 42B which is a second rotating ring.
  • each of the mechanical seals 4 is composed of a combination of carbon and SiC as in FIG.
  • the liquid portion 22 includes a liquid portion 22A in the vicinity of the lower mechanical seal 4A, a liquid portion 22B in the vicinity of the upper mechanical seal 4B, and a liquid portion 22C above the upper mechanical seal 4B.
  • the mechanical seal 4A is provided between the liquid portion 22A and the liquid portion 22B.
  • the mechanical seal 4B is provided between the liquid portion 22B and the liquid portion 22C.
  • the solid portion 21 of the container 2 includes a solid portion 21A in the vicinity of the lower mechanical seal 4A (particularly the first stationary ring 41A) and a solid portion 21B in the vicinity of the upper mechanical seal 4B (particularly the second stationary ring 41B). including.
  • the liquid portion 22A has an inflow port 201A and an outflow port 204.
  • a decompression device 200A is provided between the liquid unit 22A and the liquid unit 22B.
  • the liquid portion 22B has an inflow port 201B and an outflow port 204.
  • a decompression device 200B is provided between the liquid portion 22B and the outlet 204.
  • the liquid portion 21C has an outlet 202.
  • a decompression device 200A may be provided between the first mechanical seal 4A and the second mechanical seal 4B.
  • This decompression device 200A is used for pressure control for each mechanical seal to seal a liquid under equal pressure conditions.
  • the lower liquid portion 22A is used as the first seal chamber
  • the upper liquid portion 22B is used as the second seal chamber
  • the first seal chamber is maintained at a pressure of about 7 MPa
  • the second seal chamber is about 3.5 MPa. It is kept under pressure.
  • the first seal chamber and the second seal chamber are shaft-sealed at substantially equal pressures.
  • the first AE sensor 5A is located on the side surface of the outer wall of the container 2 at the position ZA ahead of the propagation path PA in which the direct wave from the first mechanical seal 4A mainly passes through the solid portion 21A. is set up.
  • the second AE sensor 5B is installed at the position ZB ahead of the propagation path PB in which the direct wave from the second mechanical seal 4B mainly passes through the solid portion 21B.
  • the propagation path PA is a path that minimizes the propagation distance of the AE wave from the first mechanical seal 4A through the solid portion 21A.
  • the propagation path PB is a path that minimizes the propagation distance of the AE wave from the second mechanical seal 4B through the solid portion 21B.
  • the transmission loss is smaller in the path in which the AE wave is reflected at the interface of the medium and propagates through the solid portion without passing through the liquid portion. Therefore, as the installation positions of the AE sensors 5 (5A, 5B), the positions (ZA, ZB) corresponding to the combination of the propagation paths in which the propagation distance is as small as possible among the propagation paths via the solid portion 21 are selected. To.
  • a sub AE sensor 5n is installed as a third AE sensor on the upper surface of the container 2 in order to cancel the noise related to the rotating shaft 3, as in the second embodiment. There is.
  • the lower side of FIG. 19 briefly shows an example of the circuit configuration according to the third embodiment.
  • the signal acquisition unit 600 of FIG. 6 acquires the first AE signal from the first AE sensor 5A, the second AE signal from the second AE sensor 5B, and the third AE signal from the sub AE sensor 5n.
  • the third AE signal includes noise related to the rotating shaft 3.
  • the signal acquisition unit 600 or the condition monitoring device 10 includes subtractors 191, 192.
  • the subtractor 191 subtracts the third AE signal from the first AE signal.
  • the subtractor 192 subtracts the third AE signal from the second AE signal.
  • the effect of noise related to the rotation axis 3 is removed to some extent from the signal after each subtraction.
  • the state determination unit 10B of the state monitoring device 10 determines the state for each subtracted signal.
  • the state determination unit 10B determines the state of the first mechanical seal 4A with respect to the signal from the subtractor 191 and determines the state of the second mechanical seal 4B with respect to the signal from
  • the first AE sensor 5A and the second AE sensor 5B are installed at positions sufficiently separated from each other so that the AE wave and the second mechanical seal 4B using the first mechanical seal 4A as a sound source are installed. Can be distinguished from the AE wave whose sound source is. This utilizes the property that the straightness of the AE wave increases as the frequency of the ultrasonic wave increases. Further, the higher the frequency, the larger the propagation attenuation. Based on these properties, two AE sensors 5 are installed at distant positions (ZA, ZB) as described above. As a result, the state of the first mechanical seal 4A can be determined from the first AE signal, and the state of the second mechanical seal 4B can be determined from the second AE signal.
  • the signal intensity of the AE wave from the second mechanical seal 4B is small, and in the second AE signal, the signal intensity of the AE wave from the first mechanical seal 4A is small. Since this state monitoring system determines the state of an AE wave in a high frequency range as the frequency range H1, it is possible to detect with high sensitivity by taking advantage of the propagation characteristics at a high frequency as described above.
  • the lower first mechanical seal 4A and the upper second mechanical seal 4B may have the same material, shape, or the like, or may have different configurations.
  • each mechanical seal may have a different configuration depending on the function of converting the pressure difference between the liquid parts.
  • the mechanical seal 4 of each stage has the same configuration. Since the propagation path and the position of the AE sensor 5 are different in each stage, the sensitivity using each AE signal may be different, but it can be similarly detected by the determination using the predetermined frequency range H1. In other embodiments, different frequency ranges H1 may be set for each stage of the mechanical seal 4 and the corresponding AE sensor 5.
  • FIG. 20 shows the configuration in the modified example (referred to as modified example 6) of the third embodiment.
  • a modification 6 is a case where the container 2 has a two-stage mechanical seal 4, and one AE sensor 5 is installed at one place on the side surface.
  • the position ZAB which is the installation position of one AE sensor 5, is, for example, a propagation path PA1 from the first mechanical seal 4A via the solid portion 21A and a propagation path from the second mechanical seal 4B via the liquid portion 22B. Both with PB1 are selected as the position to reach one place.
  • the AE signal from one AE sensor 5 contains both components of the AE wave from the propagation path PA1 and the AE wave from the propagation path PA2.
  • the condition monitoring device 10 collectively determines the status of the first mechanical seal 4A and the second mechanical seal 4B for the AE signal from one AE sensor 5. In this state determination, it is difficult to distinguish the state of each mechanical seal 4, but if there is an abnormality in either or both of the two-stage mechanical seal 4, it is regarded as an abnormality sign state regarding the two-stage mechanical seal 4. It can be judged and detected.
  • This abnormality sign state is a state indicating that one or both of the first mechanical seal 4A and the second mechanical seal 4B has an abnormality sign.
  • the number of AE sensors 5 installed can be reduced.
  • one AE sensor 5 may be provided on the upper surface of the container 2.
  • the condition monitoring system according to the fourth embodiment of the present invention will be described with reference to FIG.
  • the condition monitoring system of the fourth embodiment shows a configuration in which the container has a one-stage mechanical seal, and the orientation of the AE sensor is optimized to increase the sensitivity.
  • FIG. 21 shows the configuration in the fourth embodiment.
  • A shows the cross section of the container 2, the installation position of the AE sensor 5, and the like.
  • B shows an outline of an installation example of the AE sensor 5 and the jig 6 with respect to the side surface of the container 2 corresponding to (A).
  • the AE sensor 5 is installed at one position on the side surface of the container 2.
  • the AE sensor 5 is interposed via a jig 6 for conversion so that the receiving surface of the AE sensor 5 is perpendicular to the direction of the direct wave propagation path P1 from the mechanical seal 4. Is installed.
  • high frequency AE waves travel straight and propagate.
  • the direction in which the AE sensor 5 is installed is such that the receiving surface is perpendicular to the propagation direction of the incoming AE wave.
  • This jig 6 has a shape for converting so that the receiving surface of the AE sensor 5 is perpendicular to the direction of the propagation path P1.
  • the side surface of the container 2 is a curved surface, has an angle ⁇ with respect to the direction of a suitable propagation path P1 having a short propagation distance, and is not vertical.
  • One surface of the jig 6 is fixed to the curved surface of the side surface of the container 2 as a concave curved surface.
  • a coplant 8 is provided between the jig 6 and the side surface of the container 2 as described above.
  • the other surface of the jig 6 is a plane having an angle perpendicular to the direction of the propagation path P1, and the receiving surface of the AE sensor 5 or the plane of the holder 501 described above is fixed to the plane. In this way, the sensitivity can be increased by making the receiving surface of the AE sensor 5 perpendicular to the direction of the propagation path P1 by using the jig 6.
  • each AE sensor 5 is optimized by using each jig 6 in association with each mechanical seal 4 of each stage. Is possible as well.
  • FIG. 22A shows a configuration such as a cross section of the container 2 in the fifth embodiment.
  • (B) and (C) show modified examples.
  • the rotary machine 1 is a case where the container 2 has a two-stage mechanical seal 4 (4A, 4B).
  • two AE sensors 5 (5A, 5B) are installed at one selected suitable position X5 on the upper surface of the outer wall of the container 2 via a jig 6 for conversion.
  • Each AE sensor 5 is installed so as to face the AE wave from the corresponding sound source.
  • the propagation path p21 is one of the paths in which the AE wave propagates as a direct wave from the second mechanical seal 4B via the solid part 21B.
  • the second AE sensor 5B is installed on the second surface s2 of the jig 6 at position X5 so that the receiving surface is perpendicular to the direction of the propagation path p21.
  • Propagation paths p11 and p12 are paths that propagate inside the container 2 while being reflected by the inner wall of the container 2 using the first mechanical seal 4A as a sound source.
  • the propagation path p11 is a path in which the AE wave from the first mechanical seal 4A reaches the position Z5 on the side surface as a direct wave mainly via the solid portion 21A.
  • the propagation path p12 is a path in which the reflected wave reflected at the side surface position Z5 reaches the upper surface position X5 mainly via the solid portion 21B corresponding to the propagation path p11.
  • the first AE sensor 5A is installed on the first surface s1 of the jig 6 at position X5 so that the receiving surface is perpendicular to the direction of the propagation path p12.
  • a suitable position X5 in which two AE sensors 5 can be installed can be found as shown in the figure.
  • This position X5 is a position where both the direct wave from the second mechanical seal 4B and the reflected wave from the first mechanical seal 4A arrive and their signal intensities are sufficient.
  • Such a suitable position can be determined by calculation, for example, by visualizing the propagation path by acoustic propagation simulation by the finite element method.
  • a jig 6 having a shape for conversion that optimizes the orientation of each AE sensor 5 is fixed.
  • the jig 6 of (A) has, for example, a triangular cross section.
  • one surface of the jig 6 is a flat surface.
  • the other surface of the jig 6 has a first surface s1 and a second surface s2, and the angles are designed so as to be perpendicular to the direction of the corresponding propagation path.
  • the receiving surface of the first AE sensor 5A is fixed to the first surface s1
  • the receiving surface of the second AE sensor 5B is fixed to the second surface s2.
  • the condition monitoring device 10 determines the state of the first mechanical seal 4A based on the first AE signal from the first AE sensor 5A, and determines the state of the second mechanical seal 4B based on the second AE signal from the second AE sensor 5B.
  • the AE wave from each mechanical seal 4 can be selectively detected from one position on the outer wall of the container 2.
  • the AE sensors 5 and the like can be collectively installed at one position on the outer wall of the container 2, so that installation and maintenance are easier than when the AE sensors 5 and the like are installed at two or more places. It has the advantage of being easy to reproduce.
  • the sound absorbing material 9 is arranged in at least a part of the outer surface of the container 2 other than the installation location of the AE sensor 5 and the like. As a result, the reflected wave can be suppressed and the sensitivity can be increased.
  • the sound absorbing material 9 is provided near the outer periphery of the liquid portion 22A of the lower mechanical seal 4A.
  • the sound absorbing material 9 may be selectively arranged in the region where the reflected wave reaches a large amount on the outer wall of the container 2 based on the calculation such as the acoustic propagation simulation.
  • the angle difference in other words, the angle difference of the receiving surface or the like regarding the orientation of the two AE sensors 5 (5A, 5B) is about 90 degrees. May be good.
  • the angle formed by the directions of the two propagation paths p21 and p12 and the angle formed by the first surface s1 and the second surface s2 are about 90 degrees.
  • the angle difference between the receiving surfaces of the two AE sensors 5 in the jig 6 may be within the range of 90 degrees or more and less than 180 degrees.
  • the angle of the first surface s1 and the angle of the second surface s2 with respect to the upper surface of the container 2 which is the installation surface of the jig 6 are the same, but the angle is not limited to this and they are different. You may.
  • (C) shows an example in that case. In this example, the angle of the first surface s1 and the angle of the second surface s2 with respect to the upper surface are different, and in particular, the case where the angle formed by the first surface s1 and the second surface s2 is about 90 degrees is shown.
  • two AE sensors are installed at one suitable position (for example, position Z5) on the side surface of the container 2 in a suitable direction via a jig 6.
  • position Z5 based on the combination of the direct wave and the reflected wave
  • the position X5 based on the combination of the direct wave and the reflected wave is selected, but the position is not limited to this, and depending on the rotating device, the position due to the combination of the direct waves or the position due to the combination of the reflected waves. May be.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
  • Mechanical Sealing (AREA)
  • Sealing Devices (AREA)
PCT/JP2020/020145 2019-08-21 2020-05-21 状態監視システムおよび方法 Ceased WO2021033382A1 (ja)

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CN116848404A (zh) * 2021-03-26 2023-10-03 三菱重工业株式会社 旋转机械的摩擦位置确定装置及摩擦位置确定方法
US11965600B2 (en) 2019-01-04 2024-04-23 Sulzer Management Ag Mechanical sealing arrangement and a sensor ring for monitoring the operation of a mechanical seal arrangement

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KR102535503B1 (ko) * 2021-04-06 2023-05-26 주식회사 큐오티 스펙트로그램 (Spectrogram)을 이용한 제품 제조 공정의 유사도 분석 방법
CN117677776A (zh) * 2021-07-19 2024-03-08 株式会社华尔卡 液压设备监视系统
TWI893170B (zh) * 2021-07-21 2025-08-11 日商華爾卡股份有限公司 液壓機器監視系統
KR102736792B1 (ko) * 2022-01-04 2024-12-03 주식회사 제이비테크아이앤에스 과도 탄성파 진단 장치 및 그 동작 방법
JP7765010B2 (ja) * 2022-03-29 2025-11-06 首都高技術株式会社 打音検査システムおよびプログラム
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