JP2021103117A - Condition determination system and method - Google Patents

Abstract

To provide an art that enables a highly-accurate determination of conditions as to a rotary machine, and allows for efficiency of an operation and maintenance of the rotary machine.SOLUTION: A state determination system includes a state determination device 10 that determines a state of a rotary machine 1 having a mechanical seal 4. The state determination device 10 is configured to acquire an effective value (A) of an AE signal from an AE sensor 5 installed in the rotary machine 1, and a bearing characteristic number (G) of the mechanical seal 4, or a parameter for calculating the bearing characteristic number; prepare an A-G line drawing representing a relationship between the effective value (A) of the AE signal and the bearing characteristic number (G); calculate an index value showing a fluctuation of a shape about the line drawing of a determination object with respect to the line drawing at a time of a normal condition; determine at least a normal or abnormal state about the state of the mechanical seal 4 in accordance with the index value; and output a determination result.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique such as a state determination system for determining the state of a rotating machine.

A rotating machine such as a pump has parts such as a mechanical seal installed on a rotating shaft in a container. The mechanical seal constitutes a sealing mechanism for preventing leakage of a liquid (for example, a fluid such as water or oil) in the container. 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 is formed. For proper operation and maintenance of rotary machines, it is effective to be able to detect and determine the degree of deterioration and abnormalities of parts such as mechanical seals.

As an example of the prior art related to the above, Japanese Patent Application Laid-Open No. 2-199374 (Patent Document 1) can be mentioned. In Patent Document 1, as a method for measuring a change in the characteristics of a mechanical seal, the friction coefficient f and the friction characteristic function G are measured, and the characteristics of the mechanical seal are described from an fG graph corresponding to the relationship between them, a so-called Strivec curve. The technique for measuring changes is described. The friction characteristic function G is a number of bearing characteristics calculated from the viscosity, rotation speed, pressure, and the like of the liquid serving as the sliding surface.

Japanese Unexamined Patent Publication No. 2-199374

When maintaining a conventional rotating machine such as a pump, it depends on the type and application of the rotating machine, but for example, during regular maintenance and inspection by an operator, it is confirmed that there is no failure, etc., and the number of years of use. Parts or rotating machines are replaced according to the above. This maintenance and inspection is limited to, for example, checking the appearance of the rotating machine, checking for abnormal noise, and checking for liquid leakage. Conventionally, it is difficult to determine the state of deterioration of parts such as mechanical seals inside a rotating machine during maintenance, so it has not been performed. Even if the rotating machine or parts are not in bad condition, they may be replaced with new ones, which is not efficient from the viewpoint of cost and the like.

If you want to check the parts inside the rotating machine, there is a method in which the operator disassembles the rotating machine, takes out the parts, and checks them. However, in this method, the operation stop time of the equipment / system including the rotating machine becomes long, the maintenance work is troublesome, and the cost is high.

Another method is to incorporate a sensor, for example, a torque meter, in the rotating machine and check the output value of the sensor. The torque meter can measure the torque for calculating the friction coefficient. However, when installing a torque meter on a pump, it is necessary to install it on a rotating shaft, and it is often difficult to newly install it. With this method, it is difficult to measure and acquire friction coefficient data from a rotating machine, and it is often not realistic from the viewpoint of cost and the like.

Further, as in the example of Patent Document 1, there is a method of measuring and acquiring a friction coefficient or a strikebeck curve in order to determine the state of the mechanical seal of a rotating machine. The Strivec curve is a diagram showing the relationship between the friction coefficient and the number of bearing characteristics. The strikebeck curve reflects the condition of the sliding surface of the mechanical seal well, but data such as the friction coefficient is required. However, it is often difficult to measure and acquire data such as friction coefficient while a rotating machine such as a pump is in operation. In that case, the state cannot be determined by this method.

In addition, as an example of conventional technology, an AE sensor (AE: acoustic emission) is installed in a rotating machine to monitor and measure the effective value of the voltage of the AE signal from the AE sensor, the number of sudden AE signals generated, and the like. There is a method of determining the state of normality, abnormality, deterioration degree, abnormality sign, etc. of a part such as a mechanical seal using the measured value. In this method, for example, when the effective value of the AE signal exceeds a certain threshold value, it is determined to be in an abnormal state or the like. This method can output alerts based on real-time status determination and abnormality detection. However, this method may be difficult to detect with high accuracy, and may not be suitable for equipment / systems including rotating machines for applications where the operation is not stopped as much as possible.

An object of the present invention is to provide a technique for determining a state of a rotating machine, which can determine the state with high accuracy and can improve the efficiency of operation and maintenance of the rotating machine.

A typical embodiment of the present invention has the following configurations. The state determination system of one embodiment is a state determination system including a state determination device for determining the state of a rotating machine having a mechanical seal, and the state determination device is from an AE sensor installed in the rotating machine. The effective value of the AE signal and the number of bearing characteristics of the mechanical seal or the parameter for calculating the number of bearing characteristics are acquired, and a diagram showing the relationship between the effective value of the AE signal and the number of bearing characteristics is shown. It is created, an index value indicating a change in the shape of the diagram to be determined with respect to the diagram in a normal state is calculated, and at least a normal or abnormal state regarding the state of the mechanical seal is determined according to the index value. And output the judgment result.

According to a typical embodiment of the present invention, it is possible to determine a state such as an abnormality with high accuracy in a state determination technique for a rotating machine, and to improve the efficiency of operation and maintenance of the rotating machine.

It is a figure which shows the whole structure of the state determination system of Embodiment 1 of this invention. It is a figure which shows the structure of the rotary machine in Embodiment 1. It is a figure which shows the structure of the mechanical seal in Embodiment 1. FIG. It is a figure which shows the time chart which concerns on maintenance work in Embodiment 1. FIG. FIG. 5 is a diagram showing a functional block configuration example of a signal detection circuit and a state determination device according to the first embodiment. It is a figure which shows the example of the Strivec curve in Embodiment 1. FIG. It is a figure which shows the example of the strikebeck curve in the normal state in Embodiment 1. FIG. It is a figure which shows the example of the strikebeck curve at the time of an abnormal state in Embodiment 1. FIG. In the first embodiment, it is a figure which superimposes a plurality of strikebeck curves at the time of a plurality of measurements. FIG. 5 is a diagram showing an example of an AG diagram showing the relationship between the AE signal effective value (A) and the number of bearing characteristics (G) in the normal state in the first embodiment. FIG. 5 is a diagram showing an example of an AG diagram in an abnormal state in the first embodiment. It is a figure which shows the AG diagram of each time which concerns on maintenance work in Embodiment 1. FIG. It is a figure which shows the screen display example in Embodiment 1. It is a figure which shows the functional block configuration example of the state determination apparatus in the state determination system of Embodiment 2 of this invention. FIG. 2 is a diagram showing an example of an f-R diagram showing the relationship between the friction coefficient (f) and the rotation speed (R) in an abnormal state in the second embodiment. FIG. 2 is a diagram showing an example of an AR diagram showing the relationship between the AE signal effective value (A) and the rotation speed (R) in an abnormal state in the second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In principle, the same parts are designated by the same reference numerals in all drawings, and repeated description will be omitted.

(Embodiment 1)
The state determination system and method according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 12. The state determination system of the first embodiment shown in FIG. 1 and the like is a system for determining the state of the rotating machine 1 including the mechanical seal 4, and is a system that supports the maintenance work of the rotating machine 1 by the user U1. The state determination method of the first embodiment is a method having a step executed by the state determination device 10 in the state determination system of the first embodiment. The state determination system and method of the first embodiment include processes and steps executed based on an operation by a user U1 who is a worker who performs work such as maintenance of the rotary machine 1. The user U1 performs periodic maintenance and inspection work (FIG. 4 described later) on the rotary machine 1. The rotary machine 1 is automatically controlled to an operating state during normal times other than maintenance.

In the state determination system of the first embodiment of FIG. 1, the state determination device 10 increases or decreases the rotation speed R of the mechanical seal 4 during maintenance work of the rotating machine 1 by the user U1. In the period of, the data including the AE signal and the parameter that can calculate the number of bearing characteristics (G) is acquired. The state determination device 10 creates an AG diagram showing the relationship between the AE signal effective value (A) and the number of bearing characteristics (G) based on the acquired data. The state determination device 10 determines the variation or difference in the shape of the diagram based on the comparison between the created determination target diagram and the diagram in the normal state, based on the conditions such as the set threshold value. As a result, the state determination device 10 determines the state of the sliding surface of the mechanical seal 4, such as normal, abnormal, deterioration degree, and sign of abnormality. Further, the state determination device 10 further determines whether or not the mechanical seal 4 or the rotating machine 1 including the mechanical seal 4 needs to be replaced based on the state of the determination result. The state determination device 10 outputs the determination result to the user U1.

At the time of maintenance work, it is necessary to temporarily end or restart the operation of the rotating machine, but the state determination system of the first embodiment performs an operation of lowering or increasing the rotation speed R accompanying the maintenance work. By using it, the data at that time is measured and acquired to judge the state. This makes it possible to efficiently determine the state when the equipment is stopped due to maintenance work. Further, depending on the state of the determination result, the rotating machine 1 or the parts can be replaced, the down time of the equipment / system can be reduced, and the operating rate can be increased. In addition, efficient state determination can reduce maintenance work time, labor, and cost.

[Status judgment system]
FIG. 1 shows the overall configuration of the state determination system of the first embodiment. This condition monitoring system is roughly classified into a rotating machine 1, a signal detection circuit 70, a condition determination device 10, and the like, which are connected via an electric circuit or communication. The rotary machine 1 includes a control device 30, a rotary power source 31, a container 2, a rotary shaft 3, a mechanical seal 4, and the like. The signal detection circuit 70 includes a preamplifier 71, a signal processing circuit 72, an oscilloscope 73, and the like. The user U1 is a worker who operates the state determination device 10 and performs maintenance work and the like related to the rotary machine 1. The state determination device 10 can be arranged at a position distant from the rotating machine 1 via the signal detection circuit 70.

For the sake of explanation, the X, Y, Z, and C directions shown in the figure may be used as the direction. 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. Further, 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 in FIG. 1 as a cylindrical shape, a disk shape, or an annulus shape.

The container 2 is filled with a liquid. A rotary power source 31 is connected to a rotary shaft 3 that goes out of the container 2. A control device 30 is connected to the rotational power source 31. The control device 30 is a pump controller and controls the operation and stop of the rotating machine 1 including the rotating shaft 3. The control device 30 controls, for example, the rotation speed R (corresponding speed V) of the rotation shaft 3 by giving a drive control signal to the rotation power source 31. The rotational power source 31 rotates the rotary shaft 3 in the C direction at the rotation speed R 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. As the rotating shaft 3 rotates, the rotating ring 42 rotates with respect to the stationary ring 41.

An AE sensor 5 is fixed to a part of the container 2, for example, one place on the side surface of the outer wall in the manner of the AE sensor unit 50. The AE sensor 5 detects an AE wave 53 generated mainly by using the mechanical seal 4 as a sound source when the rotating machine 1 is in operation, and outputs the AE signal 52 as an AE signal 52. In this example, the side surface of the outer wall of the container 2 is a curved surface, and the AE sensor unit 50 including a jig is used in order to appropriately fit the flat receiving surface of the AE sensor 5 to the curved surface. This jig connects the curved surface of the container 2 and the flat receiving surface of the AE sensor 5. One surface of the jig is fixed to the curved surface of the container 2 so as to interpose a coplant such as an adhesive. The AE sensor 5 outputs the AE signal 52 through the cable from the output terminal.

The signal detection circuit 70 is a component for acquiring and processing an AE signal. The cable from the AE sensor 5 is connected to the preamplifier 71. The AE signal amplified by the preamplifier 71 is input to the signal processing circuit 72 through a cable. In the signal processing circuit 72, filtering and further amplification are performed. The AE signal output from the signal processing circuit 72 is input to the oscilloscope 73 through a cable. After the analog-to-digital conversion of the AE signal, the oscilloscope 73 monitors and records the waveform of the AE signal. The AE signal data 54 output from the oscilloscope 73 is input to the connection interface unit 103 of the state determination device 10. The communication related to the AE signal 52 is not limited to wired communication, but may be wireless communication.

The state determination device 10 is a device having a function of determining the state of the rotating machine 1. The state determination 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 state determination 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 determination function. The processor 101 realizes each 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 and the like. The memory 102 stores setting information 121, AE signal data described later, diagram data, and the like. The setting information 121 includes system setting information and user setting information related to the 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 an input operation of the user U1. The display device 105 is a device that displays information and images on the display screen for the user U1. 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.

The function of the state determination device 10 may be merged and mounted on the control device 30. The function of the signal detection circuit 70 may be combined and mounted on the state determination device 10. The state determination device 10 may be divided into a plurality of devices. Another computer, storage device, communication device, or the like may be connected to the state determination device 10.

The state determination device 10 may be connected to the control device 30 of the rotating machine 1 by communication 55 for control. In the system configuration example of FIG. 1, the control device 30 which is a pump controller and the state determination device 10 are connected by communication 55. For example, the state determination device 10 transmits a request to the control device 30 when acquiring information such as the required rotation speed R from the rotating machine 1, and the control device 30 transmits information such as the rotation speed R according to the request. It may be transmitted to the state determination device 10. The control device 30 has information such as the rotation speed R related to the drive control, and can be output externally. The state determination device 10 can acquire data 56 such as various parameters such as the rotation speed R from the control device 30 by communication 55. The details of the parameters will be described later, but include the rotation speed R (or velocity V) of the rotating shaft 3, the load P on the rotating shaft 3, and the temperature T of the liquid in the container 2.

Further, the data 56 may include instructions and control signals related to the start and stop of the rotating machine 1 by the control device 30. Further, when the state determination device 10 performs operation control related to the rotation speed R of the rotating machine 1, the control device 30 transmits control information to the control device 30, and the control device 30 follows the control information to control the rotation speed R of the rotating machine 1. Etc. may be controlled.

In another embodiment, the control device 30 and the state determination device 10 may not be connected by communication 55. In that case, at the time of maintenance, the user U1 may perform an operation of ending the operation or restarting the operation on the control device 30, and at the same timing, perform an operation such as instructing the state determination device 10 to execute the state determination. .. The state determination device 10 provides the user U1 with a graphical user interface (GUI) or the like for such a state determination operation during maintenance.

[Rotating machine and AE sensor]
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. The rotary machine 1 has a one-stage mechanical seal 4 in the container 2. 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 outlet 202 communicating with the liquid portion 22B on the other part of the side surface. Further, 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 control device 30 of the rotating machine 1. The decompression device 200 is provided at a position leading to the liquid portion 22A. The other part of the side surface of the outer wall 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. 2 also shows an installation example of the AE sensor 5 with respect to the container 2. In the first embodiment, one AE sensor 5 is installed at the position Z1 in the Z direction on the side surface of the outer wall of the container 2. The AE sensor 5 is composed of a receiving plate, a piezoelectric element, a damper, and the like. The piezoelectric element converts the AE wave 53 propagating to the receiving plate into an electric signal by the piezoelectric effect. The position Z1 is a position substantially close to the height position of the mechanical seal 4. The position Z1 is selected as a position where the propagation path of the AE wave 53 is as short as possible from the stationary ring 41 via the solid portion 21 of the container 2. Further, the side surface of the outer wall of the container 2 is, for example, a substantially columnar curved surface as shown in FIG. In this example, the AE sensor 5 is installed at one location in the C direction on this curved surface. In this example, an AE sensor unit 50 including a jig 51 for suitably attaching the AE sensor 5 to this curved surface is used. The jig 51 of the AE sensor unit 50 is fixed to the curved surface of the outer wall of the container 2 with a couplant as an acoustic transmission medium interposed therebetween. The material of the coplant is grease, wax, adhesive or the like. The AE sensor unit 50 houses the AE sensor 5 and the like in a waterproof shield case. The AE sensor 5 is pressed against the surface on the jig 51 side by a spring in the shield case. A cable is connected to the output terminal of the AE sensor 5. With such a configuration, the AE sensor 5 detects the AE wave 53 from the mechanical seal 4 with high sensitivity.

With the operation of the rotating machine 1, an AE wave 53 is generated as a sound wave from the sliding surface of the mechanical seal 4. The propagation path of the AE wave 53 is as follows, for example. The AE wave 53 propagates directly from the stationary ring 41 through the solid portion 21 of the container 2 as a direct wave to reach each surface of the outer wall. The AE wave 53 propagates through the coplant and the jig of the AE sensor unit 50 to reach the wave receiving surface of the AE sensor 5, for example, at the position Z1. The AE sensor 5 detects the AE wave and outputs it as an AE signal 52. The propagation path from the mechanical seal 4 to the AE sensor 5 is selected so that, for example, the propagation distance is as short as possible, air does not intervene, and the propagation loss is low. According to the above installation example, the AE sensor 5 can detect the AE wave 53 with high sensitivity. The mode of the AE sensor 5 is not limited to the above example, and the AE sensor 5 may be installed on, for example, a flat surface on the upper side of the container 2 in the Z direction. Further, the AE sensor 5 may be installed at a position corresponding to the propagation path of the container 2 via the liquid portion 22.

[mechanical seal]
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 fixed to the container 2 side is arranged on the upper side of the rotating ring 42. In the mechanical seal 4 of this example, 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 rotation shaft 3 rotates in the C direction at a rotation speed R and a speed V. The rotating ring 42 is integrally rotated 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 (sliding surface s1) and the upper surface of the rotating ring 42 (sliding surface s2) have a small gap (distance h) in close proximity to the liquid film 43. Is formed. Specifically, the sliding surface of the liquid film 43 has a sliding surface s1 on the stationary ring 41 side and a sliding surface s2 on the rotating ring 42 side. A load F is applied to the mechanical seal 4 based on the load P on the rotating shaft 3. 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. The friction due to the viscosity of the liquid in the liquid film 43 of the mechanical seal 4 is the main sound source, and the AE wave 53 of FIG. 2 is generated.

FIG. 3B shows a ring shape when the liquid film 43 (corresponding sliding surface) of the mechanical seal 4 is viewed in a horizontal plane (XY plane). The radius r, the width w, and the area A1 in the ring shape of the sliding surface are shown.

[Maintenance work (1)]
FIG. 4 shows a schematic time chart regarding the operation and maintenance work of the pump which is the rotary machine 1, and corresponds to the workflow seen from the user U1. The user U1 who is a worker executes roughly three steps such as termination of operation of the rotary machine 1, maintenance work, and resumption of operation for each maintenance work in the periodic maintenance and inspection work.

FIG. 4A shows a first example of the time chart according to the first embodiment. In this chart, the horizontal axis represents time and the vertical axis represents the rotation speed R of the rotating machine 1. Periods 401, 402, etc. indicate normal operating conditions. The periods 411, 412, etc., which are the periods between those periods, indicate the maintenance work and the outage state. In the period 411 and the like, the user U1 performs maintenance and inspection work with the rotating machine 1 stopped. For example, the period 411 corresponds to the first maintenance and inspection work for a certain rotary machine 1, and the period 412 corresponds to the second maintenance and inspection work. Although the period 401 and the like are shortened and shown, the maintenance period is actually much longer than the maintenance period of 411 and the like. The length of the continuous operation period 401 and the like and the timing of regular maintenance depend on the type and application of the rotary machine 1.

The periods 421, 422, etc. indicate the operation end period when shifting from the normal operating state such as the period 401, etc. to the maintenance work such as the period 411. In this period 421 or the like, for example, the rotation speed R is lowered at a constant rate by the drive control from the control device 30. The periods 431, 432 and the like indicate the operation restart (in other words, start-up) period when shifting from the maintenance work of the period 411 and the like to the normal operating state. In this period 431 and the like, for example, the rotation speed R is increased at a constant rate by the control from the control device 30. In this example, the rotation speed R in a normal operating state such as the period 401 is set to a predetermined rotation speed RA. The maintenance period 411, the previous period 421, and the subsequent period 431 can be combined into one maintenance period.

In the time chart of this first example, at each maintenance work, the state determination device 10 is based on the operation of the user U1, and as shown by the double circle, the period 421, which is the operation end period before maintenance, etc. Then, an automatic check before maintenance (which is the first judgment) is executed. This first judgment is indispensable. Further, in this first example, at each maintenance work, the state determination device 10 is based on the operation of the user U1 and has a period of 431 or the like, which is an operation restart period after maintenance, as indicated by a single circle. Execute an automatic check (second judgment) after maintenance.

The state determination device 10 utilizes the decrease in the rotation speed R (or speed V) during the operation end period such as the period 421, and the data of the parameters such as the AE signal and the rotation speed R from the rotating machine 1 for the first determination. To get. The state determination device 10 determines the state of the mechanical seal 4 from the determination of the fluctuation of the AG diagram created based on the data. As a result of the first determination, for example, when it is determined that an abnormal state (or a state having a large degree of deterioration) or a state requiring replacement is determined, the user U1 replaces the rotating machine 1 with a new rotating machine in a period of 411 or the like. In the case of the rotary machine 1 in which only the mechanical seal 4 can be replaced, only the mechanical seal 4 may be replaced. Further, as a result of the first determination, for example, when it is determined that the normal state (or the state where the degree of deterioration is small) or the replacement unnecessary state, the user U1 performs maintenance and inspection without replacing the rotating machine 1 during the period 411 or the like. Do the work.

After that, the user U1 activates the new rotating machine after replacement or the rotating machine 1 for continuous use in the operation restart period such as period 431. The state determination device 10 utilizes the increase in the rotation speed R (or speed V) during this period 431 or the like, and acquires parameter data such as the AE signal and the rotation speed R from the rotation machine 1 for the second determination. .. The state determination device 10 determines the state of the mechanical seal 4 from the determination of the fluctuation of the AG diagram created based on the data. As a result of the second determination, for example, when it is determined to be in the normal state or the replacement unnecessary state, the user U1 continues the operation as it is. As a result of the second determination, for example, when it is determined to be in an abnormal state or a state requiring replacement, the user U1 replaces the rotating machine with a new rotating machine in an additional maintenance work period (not shown). After that, the second determination can be made in the same manner as in the period 431 and the like.

As described above, in the state determination system and method of the first embodiment, the first determination is performed when the rotating machine 1 is terminated at each maintenance work, and the first determination is performed according to the degree of deterioration of the mechanical seal 4. It is determined whether or not replacement is necessary. Therefore, efficient operation and maintenance are possible. Further, even if a defect is inherent in the new rotating machine immediately after replacement, it can be detected immediately by the second determination at the time of startup, and further measures such as replacement with a new rotating machine can be taken.

[Maintenance work (2)]
FIG. 4B shows a second example of the time chart as a modification of the first embodiment. In this modification, a specific control period 440 for determining the state is provided within the period 411 or the like, which is the period during which the operation of the rotary machine 1 is suspended for maintenance work. In this control period 440, the state determination device 10 controls the temporary operation (starting and ending) of the rotating machine 1 in order to acquire data such as an AE signal and parameters. The control period 440 has a start period 441 that constantly increases the rotation speed R, a short operation period 442 that maintains the rotation speed R, and an end period 443 that constantly decreases the rotation speed R. In this control period 440, the state determination device 10 includes data such as AE signals and parameters in the start period 441 (referred to as the first data) and data such as the AE signals and parameters in the end period 443 (second data). To) and get both. In this configuration example, the data in the above-mentioned operation end period 421 and operation restart period 431 is not acquired. Then, the state determination device 10 determines the state using the data acquired in the control period 440. In particular, this state determination is a determination using an AG diagram created by combining both the first data and the second data.

Further, in particular, in this control period 440, the state determination device 10 decreases the rotation speed R at the end of normal operation such as period 421 and increases the rotation speed R at the time of restarting normal operation such as period 431. The rotation speed R and the time may be controlled for the state determination so as to be different from the above. For example, the slope of the increase in the rotation speed R in the period 441 is gentler than the slope of the increase in the rotation speed R in the period 431. Further, the slope of the decrease in the rotation speed R in the period 443 is gentler than the slope of the decrease in the rotation speed R in the period 421. Further, the rotation speed RB reached in the period 442 is set to a value smaller than the rotation speed RA in the normal state. Of course, the control of the rotation speed R or the like in the control period 440 may be the same as the control of the rotation speed R or the like in the period 421 or the period 431.

[Signal detection circuit]
FIG. 5 shows a main functional block configuration example of the signal detection circuit 70 and the state determination device 10. The signal detection circuit 70 detects the AE signal 52 from the AE sensor 5 and arranges it into suitable AE signal data. The state determination device 10 creates a diagram using the AE signal data acquired through the signal detection circuit 70, determines the state using the diagram, and performs output control according to the determination result.

Since the AE signal 52 output from the AE sensor 5 is minute, the AE signal 52 is amplified by the preamplifier 71 connected from the AE sensor 5 with a low noise cable. The signal processing circuit 72 has, for example, a bandpass filter (BPF) 72A and a main amplifier 72B, and can be configured by one device. The BPF72A performs a filter process for extracting components in a predetermined frequency band from the amplified AE signal. The main amplifier 72B further amplifies the filtered AE signal. The amplified AE signal is input to the oscilloscope 73.

The oscilloscope 73 includes, for example, an analog-to-digital converter (ADC) 73A, a display 73B, and a storage unit 73C. The oscilloscope 73 and the signal processing circuit 72 may be configured as an integrated device. The ADC 73A converts an AE signal, which is an analog signal, into a digital signal at a predetermined sampling frequency. The converted digital signal, the AE signal, is displayed on the monitor on the display 73B and stored in the storage unit 73C (for example, a hard disk drive or a memory card) as raw data or log data. The display 73B is a waveform display and displays the state of the waveform of the detected AE signal. The user U1 can also read the AE signal data from the storage unit 73C and output it based on the operation.

[Status determination device]
The state determination device 10 includes an AE signal acquisition unit 81, a parameter acquisition unit 82, a signal calculation unit 83, a state determination unit 84, an output control unit 85, a normal data storage unit 86, a condition setting unit 87, and a maintenance operation control unit. Has 88. These functional blocks can be realized by software program processing by the processor 101 of FIG. 1, processing by a dedicated circuit, or the like.

The AE signal acquisition unit 81 inputs and acquires the AE signal data 54 from the signal detection circuit 70, and obtains the data of the effective value of the voltage of the AE signal (the AE signal effective value: A).

The parameter acquisition unit 82 acquires parameter data necessary for calculating the number of bearing characteristics (G) from, for example, the control device 30 via communication 55. For example, the parameter acquisition unit 82 acquires the rotation speed R, the load P, the temperature T, and the like. Then, the parameter acquisition unit 82 calculates the number of bearing characteristics (G) using the acquired parameters.

The parameter acquisition is not limited to this, and the following modification examples are also possible. The state determination device 10 provides a GUI screen for acquiring parameters, and the user U1 manually inputs and sets parameters on the screen. The state determination device 10 calculates the number of bearing characteristics (G) using the input parameters.

The signal calculation unit 83 inputs the AE signal data 501 acquired by the AE signal acquisition unit 81, and performs analysis processing and the like regarding the AE signal effective value (A). Further, the signal calculation unit 83 inputs the data 502 of the number of bearing characteristics (G) calculated by the parameter acquisition unit 82. The signal calculation unit 83 may calculate the number of bearing characteristics (G). Then, the signal calculation unit 83 performs a process of creating an AG diagram showing the relationship between the AE signal effective value (A) and the number of bearing characteristics (G).

The state determination unit 84 includes a first determination unit 84A and a second determination unit 84B. The state determination unit 84 inputs the diagram data G1 of the determination target diagram created by the signal calculation unit 83 and the diagram data G2 of the normal time diagram held in the normal data storage unit 86. The state determination unit 84 compares the diagrams and determines the state of the mechanical seal 4 of the rotary machine 1 based on the set determination conditions.

The first determination unit 84A compares the determination target diagram of the diagram data G1 with the normal time diagram of the diagram data G2, and determines the variation or difference in the shape of the diagram. The first determination unit 84A determines the magnitude of fluctuations and differences in the curve of the determination target diagram with respect to the curve of the normal time diagram. As a result, the first determination unit 84A determines the degree of deterioration of the mechanical seal 4, or at least a binary state of normal or abnormal. The degree of deterioration is defined by a plurality of values having three or more values. The first determination unit 84A outputs and stores the first state 511 (normal or abnormal, or the degree of deterioration) as the first determination result. Further, the second determination unit 84B determines whether or not the rotary machine 1 or the mechanical seal 4 needs to be replaced based on the first state 511. The second determination unit 84B outputs and stores the second state 512 (replacement not required or replacement required) as the second determination result.

The condition setting unit 87 sets conditions such as a threshold value used by the state determination unit 84. At least one condition is set by default in advance. The conditions include a threshold value regarding the degree of variation in the shape of the diagram, and may be defined by the amount of variation, the volatility, and the like. The user U1 can confirm this condition and set the user on the screen described later provided by the state determination device 10. The state determination unit 84 performs the above state determination according to the conditions including the threshold value set by the condition setting unit 87.

The normal state data storage unit 86 is a part that stores the diagram data in the normal state in advance based on the diagram data created by the signal calculation unit 83 and the determination result in the state determination unit 84. This normal state data is diagram data at the time of at least one measurement, for example, when it is determined to be a normal state at the time of introduction of the rotary machine 1. Further, the state determination device 10 provides a screen for registering and confirming the normal time diagram data, and according to the operation of the user U1, the diagram data selected from the plurality of diagram data is converted into the normal time diagram data. You may register as.

Further, not limited to this, the state determination device 10 including the normal data storage unit 86 stores the diagram data and the determination result at the time of each maintenance in the past as log data in the case of periodic maintenance and inspection. You may. Further, the state determination device 10 may store the diagram data at the time of abnormality occurrence, the determination result, and the like as log data. For example, the state determination device 10 includes the measured AE signal data, the created diagram data, and the information such as the maintenance date and time (≈ measurement date and time), the ID of the target rotating machine 1, the ID of the operator (user U1), and the like. Information / data such as the state determination result or the output control content is associated and stored in the storage unit in the state determination device 10. The state determination device 10 displays the information selected based on the log data and the like based on the operation of the user U1 on the display screen together with the GUI. The user U1 can confirm the information on the display screen at a desired time.

In the first embodiment, the comparison source with respect to the determination target diagram is the preset normal time diagram data, but the present invention is not limited to this. In the modified example method, the comparison source may be the diagram data created and saved at the time of the previous maintenance at the time of determination at the time of maintenance at a certain time. In the case of this method, conditions such as another threshold value corresponding to the method may be set and used for the state determination.

The maintenance operation control unit 88 is not an essential part and can be omitted. The maintenance operation control unit 88 controls the operation peculiar to the maintenance based on the communication 55 with the control device 30. Specific operation control examples are as follows. This operation control corresponds to a time chart as in the example of (A) or (B) of FIG. The maintenance operation control unit 88 communicates with the control device 30 based on the operation of the user U1 for, for example, the maintenance period 411. The operation control unit 88 during maintenance transmits an instruction to the control device 30 to end the operation of the rotary machine 1 during the period 421 before maintenance, and during the period 421, the control device 30 sends parameter data such as the rotation speed R and the like. To get. Further, the operation control unit 88 during maintenance transmits an instruction to the control device 30 to restart the operation of the rotary machine 1 during the maintenance period 431, and during the period 431, the control device 30 sends a parameter such as the rotation speed R or the like. Get the data of. In this way, the state determination device 10 can efficiently perform the state determination by actively cooperating with the control device 30. In the case where the maintenance operation control unit 88 is not provided, the user U1 may operate both the state determination device 10 and the control device 30 in order.

The output control unit 85 performs output control according to the state of the determination result of the state determination unit 84. Examples of this output control include display of the status of the determination result, alert output, monitor display, operation control, and the like. The output control unit 85 displays the status of the determination result (first state 511 and second state 512) on the display screen of the display device 105 of FIG. 1 together with the GUI. For example, when the state 511 is "normal" and the state 512 is "replacement not required", the output control unit 85 displays "the mechanical seal is in the normal state" and "this time, the pump does not need to be replaced." A message such as "." May be displayed. For example, when the state 511 is "abnormal" and the state 512 is "replacement required", the output control unit 85 displays "the mechanical seal is in an abnormal state" and "this time, the pump needs to be replaced". You may display a message such as "." That is, the output control unit 85 outputs information for support and guidance regarding maintenance work to the user U1 by GUI.

When the state 511 is "abnormal" or the degree of deterioration is large, the output control unit 85 outputs an alert corresponding to the state 511. The alert output may be, for example, an alert voice output from the speaker 106 of FIG. 1 or an alert light emission of the lamp 107. The alert output may be an alert information display on the display screen of the display device 105, or a notification or the like through a communication interface. The alert output may be provided with a plurality of levels of alerts according to the degree of deterioration.

As the monitor display, a determination target diagram, a normal time diagram, and the like may be displayed on the display screen of the display device 105 of FIG. At the time of maintenance work, the user U1 can recognize the state of the mechanical seal 4 of the rotating machine 1 from the monitor display or the like, and can take measures such as replacement according to the state.

Further, the output control unit 85 may perform predetermined operation control of the rotary machine 1 according to the type of the rotary machine 1 and according to the state of the determination result. This operation control is performed in cooperation including communication 55 between the state determination device 10 and the control device 30. Examples of the operation control include stopping the operation of the rotating machine 1, controlling to reduce the rotation speed V, controlling to reduce the load P, and pressure control by the decompression device 200 (FIG. 2). Such operation control can be applied to the case of the rotary machine 1 of a type in which there is no problem in stopping the operation or the like.

[Status judgment]
Next, the details of the state determination will be described. The state determination unit 84 of FIG. 5 calculates, for example, an index value representing a change in shape in two diagrams, a normal time diagram and a determination target diagram. For example, when the amount of fluctuation or the fluctuation rate between the two diagrams is equal to or greater than the threshold value set in the condition, the state determination unit 84 determines that the state is not normal, that is, an abnormal state or a state of a sign of abnormality. For example, the normal state is defined as a value = 0, the abnormal state is defined as a value = 1, and so on. Alternatively, the state determination unit 84 may calculate the degree of deterioration according to the amount of fluctuation or the volatility between the two diagrams. The state determination unit 84 may calculate the degree of deterioration by, for example, determining which threshold range the fluctuation amount or the like falls within by using a plurality of predetermined thresholds included in the conditions. In this case, the degree of deterioration takes, for example, one of three or more values. For example, when the fluctuation amount is less than the first threshold value, the degree of deterioration = level 1, when the fluctuation amount is equal to or more than the first threshold value and less than the second threshold value, the degree of deterioration = level 2, and when the fluctuation amount is equal to or more than the second threshold value, It may be determined that the degree of deterioration = level 3.

[Strivec curve]
FIG. 6 first shows a general example of a Stribeck curve for a mechanical seal. This Strivec curve is a graph in which the friction coefficient (f) is taken as the vertical axis and the number of bearing characteristics (G) is taken as the horizontal axis. The friction coefficient f is a friction coefficient on the sliding surface (the liquid film 43 described above), and changes according to the number of bearing characteristics (G). The lower side of FIG. 6 shows a model of the sliding surface corresponding to the mechanical seal 4. This model has a lubricant between the first solid (eg, the stationary ring 41 corresponds) and the second solid (eg, the rotating ring 42 corresponds). The lubricant corresponds to the above-mentioned liquid film 43 and is composed of the fluid in the container 2.

The bearing characteristic number (G) consists of the viscosity N of the lubricant, the speed V of the sliding surface, and the load F (surface pressure) applied to the sliding surface. Specifically, it is defined as G = (N × V) / F.

The G value range of the Strivec curve is roughly divided into a fluid lubrication region 601, a mixture lubrication region 602, and a boundary lubrication region 603. Conditions are set so that a general mechanical seal slides in the fluid lubrication region 601. In the fluid lubrication region 601, the sliding surfaces (s1, s2) are covered with a lubricant, the sliding surfaces (s1, s2) are not in contact with each other, and the distance h between solids is larger than the surface roughness S. large. The boundary lubrication region 603 is in a state where a part of the sliding surface is in contact with the boundary lubrication region 603, and the distance h is close to zero. The mixed lubrication region 602 is an unstable region between the fluid lubrication region 601 and the boundary lubrication region 603, and the distance h is close to the surface roughness S. In the range 604 of the fluid lubrication region 601 and the mixture lubrication region 602, continuous dynamics act. In the range 605 of the mixed lubrication region 602 and the boundary lubrication region 603, the mechanics of contact acts.

The sliding surface of the mechanical seal is initially in the fluid lubrication region 601. However, the friction coefficient f decreases as the wear of the sliding surface progresses, and the sliding surface shifts to the mixed lubrication region 602. As the wear progresses further, the friction coefficient f increases, and the friction coefficient f shifts to the boundary lubrication region 603. As an example of the state determination, the fluid lubrication region 601 generally corresponds to a normal state or a state with a small degree of deterioration, and the mixed lubrication region 602 and the boundary lubrication region 603 correspond to an abnormal state or a state with a large degree of deterioration. To do.

[Judgment method]
The strikebeck curve well reflects the state of the sliding surface of the mechanical seal. However, when determining the state using the Strivec curve, it is necessary to acquire data and information on the friction coefficient (f). With a normal pump, it may be difficult to obtain data and information on the friction coefficient (f). The rotary machine 1 according to the first embodiment is a pump in which it is difficult to obtain data and information on the friction coefficient (f). Therefore, the state determination system of the first embodiment uses a determination method that does not require acquisition of friction coefficient (f) data / information from the rotating machine 1.

Further, in the case of the conventional determination method using the AE signal, the effective value of the AE signal may gradually change with time even when the mechanical seal is slid under the same sliding conditions. For example, the AE signal effective value measured during periodic maintenance may change from the AE signal effective value measured during the previous maintenance. In such a case, it is difficult to determine the state with high accuracy by the state determination method by comparing the effective value of the AE signal with the predetermined threshold value. Therefore, in the state determination method of the first embodiment, data such as an AE signal is acquired when the rotation speed R rises or falls during maintenance work, and the relationship between the AE signal effective value (A) and the bearing characteristic number (G). This is a method of determining the state from the fluctuation of the diagram using the AG diagram representing.

[Example of Strivec curve]
(A) on the left side of FIG. 7 shows an example of a strikebeck curve when the mechanical seal of the rotating machine is in a normal state. This Strivec curve is a diagram (f-G diagram) in which the vertical axis is the friction coefficient (f) and the horizontal axis is the number of bearing characteristics (G). Both the G value and the f value are dimensionless quantities. The notation of the G value, for example, "1.E-10" represents ^{1 × 10 -10.} In this example, as a measurement using a rotating machine for experiments by the present inventor, when the load is 2500 N, the rotation speed R is increased from 0 rpm to 6000 rpm at the start and decreased from 6000 rpm to 0 rpm at the end. , The diagram shows the case where the operation of acquiring / measuring the f-number data is performed once and repeated three times. As shown, in this diagram, curves of almost the same shape are traced each time. The right side (B) shows a curve 701 representing the characteristics of the shape of the fG diagram.

FIG. 8 subsequently shows an example of a strikebeck curve when the mechanical seal of the rotating machine is in an abnormal state, in other words, when an abnormality occurs. This example shows a diagram when the load is 2500 N and the operation of increasing and decreasing the rotation speed R is performed once in the same manner as described above as the measurement using the rotating machine for the experiment. In the diagram of FIG. 8A and in (B) on the right side, the curve 801 is a curve representing the shape of the diagram in the normal state.

In this diagram, with respect to the curve starting from the point B1 to the point B2, when the rotation speed R rises, the range 801b including the point B3 near 4000 rpm deviates from the normal curve 801 as shown in the figure. This disengagement corresponds to an abnormal condition. Further, in the curve when the rotation speed R descends from the point near the point B2 to the point B4, the shape of the curve 801 in the normal state is not traced. Regarding the above-mentioned deviation phenomenon, in other words, the shape of the curve at the time of abnormality has a fluctuation or difference from the shape of the curve 801 at the time of normal, and when the fluctuation is larger than a certain level, it corresponds to the abnormal state. There is.

Similarly, FIG. 9 shows an example in which the fG diagram (Strivec curve) at the time of each of the first, second, and third measurements in the normal state is superimposed. Curve 900 (plot of round dots) shows a normal time diagram. The curve 901 (plot of white square points) including the points C1 to C2 is a diagram when the rotation speed R rises at the time of the first measurement, and the curve 901a is a normal time corresponding to the curve 901. The curve estimated to be a curve is shown. The curve 901 has a shape variation in the range 901b with respect to the curve 901a. The curve 902 (plot of square points) including the point near the point C2 to the point C3 is a diagram of the rotation speed R when the rotation speed R is lowered at the time of the first measurement. The curve 903 (plot of white triangulation points) including the points near the point C3 to the point C4 is a diagram when the rotation speed R rises at the time of the second measurement. The curve 904 (triangulation point plot) including the point near the point C4 to the point C5 is a diagram when the rotation speed R is lowered at the time of the second measurement. As described above, the curve of each time also has a variation with respect to the shape of the curve 901a in the normal state.

As described above, it is possible to estimate and diagnose the state of the sliding surface from the fluctuation of the Strivec curve. However, as described above, when it is difficult to obtain the friction coefficient (f), another method is required. Therefore, in the first embodiment, the AE signal effective value (A) is used instead of the friction coefficient (f). The AE signal effective value (A) and the friction coefficient (f) are parameters that are substantially linked. The state determination system of the first embodiment acquires AE signal data from the rotating machine 1, creates an AG diagram showing the relationship between the AE signal effective value (A) and the number of bearing characteristics (G), and creates an AG diagram. -The state of the sliding surface is determined from the variation in the shape of the G diagram.

[Calculation of number of bearing characteristics]
The calculation example of the bearing characteristic number (G) is as follows. The state determination device 10 acquires the following parameter data from the control device 30 of the rotary machine 1. Each parameter is represented by the following symbols.
G: Number of bearing characteristics R: Number of rotations of rotating shaft 3 V: Speed of sliding surface N: Viscosity of fluid on sliding surface F: Load on sliding surface P: Load on rotating shaft 3 T: Temperature related to sliding surface

The bearing characteristic number G with respect to the sliding surface of the mechanical seal 4 can be calculated as G = (N × V) / F. Therefore, the state determination device 10 may acquire or calculate the parameter values of the viscosity N, the velocity V (or the rotation speed R), and the load F. When the state determination device 10 cannot directly acquire those parameter values, the state determination device 10 may acquire other parameter values from which the parameter values can be calculated. The rotation speed of the sliding surface of the mechanical seal 4 is the same as the rotation speed R of the rotation shaft 3.

(1) Viscosity N: Viscosity N is a dimensionless quantity that correlates with the temperature of the liquid in the liquid film 43 constituting the sliding surface of FIG. For example, the state determination device 10 may acquire the temperature T instead of the viscosity N and calculate the viscosity N from the temperature T. The temperature T can be calculated, for example, from the temperature of the fluid in the liquid portion 22 near the mechanical seal 4 in the container 2 of FIG. 2 or the temperature of the fluid in the flow path leading to the liquid portion 22. Those temperatures can be measured by a thermometer installed in the liquid section 22 or the flow path.

(2) About speed V: If the rotation speed R of the rotation shaft 3 can be obtained, the speed V can be calculated by using the rotation speed R and the design value of the mechanical seal 4. Specifically, it is as follows. As shown in FIG. 3B, the speed V can be calculated from the rotation speed R and the outer circumference of the mechanical seal 4. Using the radius r to the outer circumference of the sliding surface (liquid film 43) of the ring-shaped mechanical seal 4 in a plan view, the outer circumference is 2πr. Therefore, it can be calculated as V = R × 2πr.

(3) Regarding the load F: The load F on the sliding surface (liquid film 43) can be calculated by using the load P on the rotating shaft 3 and the design value of the mechanical seal 4. For example, the state determination device 10 may acquire the load P instead of the load F and calculate the load F from the load P. Specifically, it is as follows. As shown in FIG. 3B, the area A1 of the ring-shaped sliding surface (liquid film 43) in a plan view and the width w of the sliding surface (difference between the outer circumference and the inner circumference) are used. The area A1 is A1 = 2πrw. The load F can be calculated by F = P / A1. Therefore, it can be calculated as F = P / A1 = P / (2πrw).

Based on the above parameters, the bearing characteristic number G can be calculated, for example, by the following equation. G = N × V / F = (N × R × 2πr) × (2πrw) / P = 4NRπ 2 r 2 w / P.

[AG diagram (1)]
FIG. 10 is an AG diagram showing the relationship between the AE signal effective value (A) and the bearing characteristic number (G), which is the processing target in the first embodiment and is created by the signal calculation unit 83 of FIG. An example is shown. The diagram of FIG. 10 is an example of a normal AG diagram corresponding to the normal Strivec curve of FIG. 7. Similar to the measurement conditions in FIG. 7, this AG diagram was obtained by repeating the operation of setting the load to 2500 N, increasing the rotation speed R from 0 rpm to 6000 rpm, and decreasing it from 6000 rpm to 0 rpm three times. It is created based on the data. The straight line 1001 shown by the broken line is a straight line that roughly represents the characteristics of the distribution and shape of the point cloud of this data. The measured values of each time are distributed as substantially the same shape along the straight line 1001.

FIG. 11 is an example of an AG diagram at the time of an abnormal state or at the time of occurrence of an abnormality, which corresponds to the Stribeck curve at the time of the abnormality of FIG. This AG diagram is created based on the data acquired by performing the same operation as the measurement conditions in FIG. 8 once. The curve 1101 (plot of double circle points) from the point D1 to the point D2 corresponds to the data when the rotation speed R rises. The curve 1102 (plot of black circle points) from the point D3 to the point D4 looks substantially a straight line and corresponds to the data when the rotation speed R is lowered. The straight line 1101a shown by the broken line indicates a straight line estimated as a normal line diagram with respect to the rising curve 1101, and corresponds to the line diagram (straight line 1001) of FIG. In this example, the curve 1101 deviates from the normal straight line 1101a in the range 1101b including the point D5 near the rotation speed R = 4000 rpm, and the slope gradually increases to the point D2. The curve 1101 looks like a quadratic curve in the range 1101b. Further, the curve 1102 at the time of descent does not trace the shape of the curve 1101 at the time of the original ascent, and is different from the shape. The effective value (A) of the AE signal fluctuates greatly so as to decrease.

That is, compared to the shape of the AG diagram (straight line 1101a) in the normal state, the shape of the AG diagram (curve 1101) at the time of abnormality has a variation or difference in a part of the range 1101b or the range 1102b. large. Therefore, the state determination device 10 can be regarded as the occurrence of an abnormal state by determining and detecting such a change or difference in the shape of the AG diagram.

In particular, the state determination device 10 does not determine the state by looking at only the data of one point at one measurement time point in the AG diagram, but at a plurality of time points (corresponding time) in the AG diagram. The state is determined by determining the shape variation from the data of a plurality of points. Judgment of shape variation includes, for example, looking at the difference in the slope of the curve of the judgment target diagram with respect to the slope of the straight line in the normal time diagram. The state determination unit 84 calculates such an inclination for each processing section in the G value range, and calculates an index value such as a fluctuation amount or a volatility of the inclination of the determination target diagram with respect to the inclination of the normal time diagram. calculate. The state determination unit 84 compares the calculated index value with the threshold value of the condition, and if it is equal to or more than the threshold value, determines an abnormal state (or a corresponding degree of deterioration). For example, if the slope increases to 20% or more under the condition that the threshold value of the volatility is 20%, it can be determined as an abnormal state. Similarly, in the case of a configuration for determining the degree of deterioration, for example, when the inclination changes by 10%, the degree of deterioration = level 1, when the degree of deterioration changes by 20%, the degree of deterioration = level 2, 30%. May be determined such that the degree of deterioration = level 3.

The determination of the shape variation in the state determination process is not limited to the above-mentioned inclination determination. For example, the state determination device 10 may determine an abnormality or the like when the partial shape of the AG diagram changes from a straight line to a quadratic curve. That is, the state determination unit 84 may use an approximate function or the like representing the shape of the diagram and determine that it is abnormal or the like when the type of the function or the like changes.

[AG diagram (2)]
FIG. 12 is a schematic diagram showing a variation example of the AG diagram each time when data measurement and state determination are performed at each maintenance work in the periodic maintenance work as in the example of FIG. .. FIG. 12A shows an outline of the AG diagram in the normal state in the first maintenance. FIG. 12B shows an outline of the AG diagram at the time of the abnormal state or the occurrence of the abnormality in the Nth maintenance. The diagram of each time from the second time to the N-1 time is the same, but the illustration is omitted. The measurement conditions are a predetermined load P, a range of rotation speed R (for example, 0 to 6000 rpm), and the like. In this example, the state of the first measurement is the normal state.

In (A), the straight line 1201 shown by the broken line is a point cloud in the AG diagram created based on the data acquired when the rotation speed R is lowered (period 421 and the like) and when it is raised (period 431). It is a straight line that roughly represents the characteristics of the distribution and shape of. Each arrow indicates when the rotation speed R rises and falls. Here, for the sake of explanation, the shape of the AG diagram is a straight line 1201, but the shape is not limited to this, and may be a curved line or the like. The section K is an example of one section in the process for determining the change in the shape of the diagram during the state determination process. The slope of the straight line 1201 in the section K is g1.

In (B), the straight line 1202 shown by the solid line is a straight line representing the shape in the AG diagram similarly created based on the data acquired at the time of the Nth operation. For comparison, the first straight line 1201 is also shown. The slope of the straight line 1202 in the same section K is g2.

As shown in the figure, at the Nth measurement, the shape of the AG diagram (straight line 1202) is tilted more than the shape of the AG diagram (straight line 1201) at the first normal time. It is fluctuating to. The slope of the straight line gradually increases in each of the 2nd to N-1th times. In this phenomenon, the mechanical seal 4 wears and deteriorates as the rotary machine 1 operates for a relatively long period of time, and in principle, the fluid lubrication region 601 shifts to the mixed lubrication region 602 as shown in FIG. It corresponds to. The present inventor applied a load to the mechanical seal using an experimental rotating machine, performed periodic measurements, and compared the AG diagrams as described above. From such a result, the present inventor confirmed the relationship between the normal / abnormal or deteriorated state of the mechanical seal and the shape of the AG diagram (for example, the inclination of the straight line). Based on such insight, the present inventor designed the function of the state determination device 10. That is, the state determination device 10 determines the state by determining, for example, a change in the inclination of the straight line as a change in shape between the normal time diagram and the determination target diagram.

The state determination unit 84 of the state determination device 10 uses the difference between the two slopes, in other words, the amount of fluctuation, or the ratio of the two slopes, in other words, the fluctuation, as an index value indicating the degree of fluctuation in the shape of the AG diagram. Use rate, etc. The state determination unit 84, particularly the first determination unit 84A, calculates the fluctuation amount or the fluctuation rate of the slope g2 of the determination target diagram with respect to the slope g1 of the normal time diagram for each section. In the above example, the fluctuation amount = (g2-g1) and the volatility = (g2 / g1).

As a condition, for example, the threshold value of the volatility is set to 20% or the like. The first determination unit 84A compares the calculated volatility for each section with the threshold value of the condition, determines that the volatility is less than the threshold value, determines that the volatility is normal, and if the volatility is greater than or equal to the threshold value, determines that the condition is abnormal. judge. In particular, the second determination unit 84B determines that the replacement is necessary when it is in an abnormal state. In the above example, the entire section K of the AG diagram is used, but the present invention is not limited to this, and a plurality of sections in the G value range of the AG diagram are used as shorter sections for each section. Similarly, the judgment can be made.

[Display screen example]
FIG. 13 shows an example of a display screen, a graphical user interface (GUI), and the like provided by the state determination device 10 to the user U1. The state determination device 10 displays information including such a GUI on the screen of the display device 105 based on the operation of the user U1 through the input device 104 of FIG. The screen (A) of FIG. 13 is an example of a screen corresponding to the function of setting the condition for determining the mechanical seal state. The user U1 can confirm and change the setting of the condition related to the state determination on this screen. On this screen, the user U1 can name and set different conditions according to the type of the target rotary machine 1, for example, the type and material of the mechanical seal 4, the installation position of the AE sensor 5, and the like. The screen of (A) has a condition setting name, a condition 1301, and an annotation as items. Condition 1301 is set to "threshold value regarding fluctuation of diagram" in this example. The threshold value under this condition 1301 is a threshold value for the magnitude of variation in the shape of the determination target diagram with respect to the shape of the normal time diagram, and is, for example, the above-mentioned volatility [%]. If the AG diagram fluctuates above this threshold value, it is determined to be in an abnormal state. User U1 can operate GUI parts such as a list box and a slide bar to adjust the threshold value up and down within a range. The user U1 can describe a comment on the setting condition, for example, information such as the type of the mechanical seal 4 and the installation position of the AE sensor 5 in the comment item. The user U1 can also set a plurality of setting conditions and use them properly according to the target. By properly using a plurality of conditions, for example, sensitivity and determination accuracy can be adjusted.

The screen (B) shows an example of a screen for management and support related to regular maintenance and inspection work as shown in FIG. This screen has maintenance name, maintenance date and time, maintenance target, maintenance worker, status determination result, and maintenance work content as items. The user U1 can confirm the content of the information in each item. The maintenance name item indicates, for example, a name that identifies each periodic maintenance work. The maintenance date / time item indicates the execution date / time of the maintenance work at that time. The maintenance target item indicates identification information of the rotary machine 1 or the like to be maintained. The maintenance worker indicates identification information such as the user U1 who has performed the maintenance work. The state determination result item indicates the state of the determination result by the state determination unit 84. The maintenance work content item indicates a text regarding the maintenance work content that can be arbitrarily described by the user U1. The user U1 can record maintenance work, check the history, and the like on such a screen.

By operating the menu or the like from the screen of FIG. 13, the user U1 can transition to the screen of the monitor display or the like by the output control unit 85 of FIG. 5 as needed. Although not shown, the monitor display screen can display an AG diagram as in the examples of FIGS. 10 and 11. Further, on the monitor display screen, as in the example of FIG. 12, a plurality of AG diagrams for a plurality of times may be displayed in parallel so that they can be compared based on the log data. It may be overlaid on the display.

[Effects, etc.]
As described above, according to the state determination system and method of the first embodiment, it is not necessary to acquire the data of the friction coefficient (f), and the mechanical seal 4 of the rotary machine 1 is deteriorated by using the AG diagram. The state such as the degree and abnormality can be determined with high accuracy and detected with high sensitivity, and the sliding state of the mechanical seal 4 can be clarified. It is possible to determine whether or not the rotating machine 1 and parts need to be replaced according to the state of the determination result. According to this system and method, the state can be determined according to the operation during maintenance work, the operation and maintenance of the rotary machine 1 can be made more efficient, and the cost related to the operation and maintenance including the replacement of the rotary machine 1 can be reduced. It can reduce maintenance work time. According to this system, it is possible to prevent the occurrence of an unplanned stop of the rotary machine 1, reduce the operation stop time, and increase the operation rate of the equipment / system. As a result of the condition judgment at the time of maintenance, if it is determined that replacement is unnecessary, unnecessary replacement with a new one and related costs can be reduced, and if it is determined that replacement is necessary, the performance and reliability of the equipment can be improved by replacement. According to this system, the state of the sliding surface of the mechanical seal can be clarified without disassembling and examining the inside of the rotating machine.

(Embodiment 2)
The state determination system and the like according to the second embodiment of the present invention will be described with reference to FIGS. 14 to 16. The second embodiment is a modification of the first embodiment, and many parts such as the system configuration of FIG. 1 can be applied in common. In the second embodiment, as a configuration point different from the first embodiment, an AR diagram using the rotation speed R is created instead of an AG diagram using the bearing characteristic number (G). The second embodiment is the same as the first embodiment in that the AE signal is used and the change in the shape of the diagram is determined at the time of determining the state.

[Status determination device]
FIG. 14 shows the functional block configuration of the state determination device 10 according to the second embodiment. This configuration is substantially the same as the configuration of FIG. 5, but as a different configuration point, the parameter acquisition unit 82 inputs and acquires information on the rotation speed R (or speed V) from the control device 30. The signal calculation unit 83 uses the data 501 of the AE signal effective value (A) acquired by the AE signal acquisition unit 81 and the information of the rotation speed R acquired by the parameter acquisition unit 82 to obtain the AE signal effective value (A). An AR diagram showing the relationship between the rotation speed R and the rotation speed R is created. The state determination unit 84 compares the normal AR diagram (G2) with the determination target AR diagram (G1) and determines the shape variation to determine the state of the rotating machine 1. To judge.

[F-R diagram]
FIG. 15 shows an f-R diagram showing the relationship between the friction coefficient f and the rotation speed R for comparison. It is not necessary for the state determination device 10 to create this diagram. The measurement conditions were a load of 2500 N and an operation of increasing and decreasing the rotation speed R in the R value range between 0 rpm and 6000 rpm. The curve 1501 (plot of white circle points) by the point cloud from the point E1 to the point E2 shows a curve based on the measurement data when the rotation speed R rises during a certain maintenance. The curve 1501a shown by the broken line shows a diagram in a normal state. In the curve 1501, the friction coefficient f decreases along the curve 1501a as the R increases. The shape of the curve 1501 changes so as to deviate from the normal curve 1501a in the range 1501b of the point E3 near the rotation speed R = 3000 rpm. The curve 1502 (plot of black circle points) from the vicinity of the point E2 to the point E4 shows a curve based on the measurement data when the rotation speed R decreases. The curve 1502 also has a shape different from that of the normal curve 1501a. The above-mentioned shape variation corresponds to an abnormal state of the mechanical seal of the rotating machine.

[AR diagram]
FIG. 16 shows an example of an AR diagram corresponding to FIG. The state determination device 10 in the second embodiment creates an AR diagram as shown in FIG. This AR diagram is a graph in which the data at each measurement time point is plotted with the horizontal axis representing the rotation speed R (unit: rpm) and the vertical axis representing the AR signal effective value (A). The curve 1601 (plot of white circle points) by the point cloud from the point F1 to the point F2 shows a curve based on the measurement data when the rotation speed R rises during a certain maintenance. The straight line 1601a shown by the broken line shows a diagram in a normal state. In the curve 1601, the AE signal effective value (A) increases along the straight line 1601a as the R rises. The shape of the curve 1601 changes so as to deviate from the normal straight line 1601a in the range 1601b including the point F3 near the rotation speed R = 3000 rpm. Specifically, in this range 1601b, the slope of the curve 1601 gradually increases with respect to the slope of the straight line 1601a in the normal state. The curve 1602 (plot of black circle points) from the vicinity of the point F2 to the point F4 shows a curve based on the measurement data when the rotation speed R decreases. The curve 1602 also has a shape different from that of the normal straight line 1601a.

As described above, even in the case of the AR diagram, as in the case of the AG diagram of the first embodiment, when an abnormality occurs, it appears as a change in the shape of the diagram. The state determination device 10 in the second embodiment can determine the state based on such a variation in the shape of the AR diagram, as in the first embodiment. It should be noted that a diagram using parameters such as velocity V that correlates with the rotation speed R instead of the rotation speed R can also be applied in the same manner.

Although the present invention has been specifically described above based on the embodiments, the present invention is not limited to the above-described embodiments and can be variously modified without departing from the gist. In the embodiment, the example of the pump has been described as an example of a rotating machine having a mechanical seal, but the same applies to other rotating machines. In other embodiments, the state determination device may determine the state of the parts other than the mechanical seal that make up the rotating machine.

1 ... Rotating machine, 2 ... Container, 3 ... Rotating shaft, 4 ... Mechanical seal, 5 ... AE sensor, 10 ... State determination device, 41 ... Static ring, 42 ... Rotating ring, 50 ... AE sensor unit, 52 ... AE signal , 70 ... Signal detection circuit.

Claims (11)

A state determination system including a state determination device for determining the state of a rotating machine having a mechanical seal.
The state determination device is
The effective value of the AE signal from the AE sensor installed in the rotating machine and the number of bearing characteristics of the mechanical seal or the parameter for calculating the number of bearing characteristics are acquired.
A diagram showing the relationship between the effective value of the AE signal and the number of bearing characteristics was created.
An index value indicating a change in the shape of the diagram to be judged with respect to the diagram in a normal state is calculated.
At least a normal or abnormal state regarding the state of the mechanical seal is determined according to the index value, and the determination result is output.
Status judgment system. A state determination system including a state determination device for determining the state of a rotating machine having a mechanical seal.
The state determination device is
The effective value of the AE signal from the AE sensor installed in the rotating machine and the rotation speed of the mechanical seal or the parameter for calculating the rotation speed are acquired.
A diagram showing the relationship between the effective value of the AE signal and the rotation speed is created.
An index value indicating a change in the shape of the diagram to be judged with respect to the diagram in a normal state is calculated.
At least a normal or abnormal state regarding the state of the mechanical seal is determined according to the index value, and the determination result is output.
Status judgment system. In the state determination system according to claim 1 or 2,
The state determination device is
The normal or abnormal state or the degree of deterioration is determined as the first state regarding the state of the mechanical seal according to the index value, and the mechanical seal or the rotation is determined based on the determination result of the first state. Judges the necessity of replacement of the machine and outputs the judgment result.
Status judgment system. In the state determination system according to claim 1 or 2,
The state determination device calculates, as the index value, the amount or rate of change in the inclination of the diagram to be determined with respect to the inclination of the diagram in the normal state.
Status judgment system. In the state determination system according to claim 1 or 2,
The state determination device receives the AE signal and the AE signal when the rotation speed decreases at the end of the operation of the rotating machine during maintenance work and when the rotation speed increases when the operation of the rotating machine resumes. The data of the parameter is acquired, and the diagram is created using the acquired data.
Status judgment system. In the state determination system according to claim 1 or 2,
The state determination device temporarily controls the rotation speed of the rotating machine for the purpose of determining the state during the maintenance period in which the rotating machine is stopped during the maintenance work, and increases the rotation speed in the control. Data of the AE signal and the parameter are acquired at least at one time of time and descent, and the diagram is created using the acquired data.
Status judgment system. In the state determination system according to claim 1 or 2,
The state determination device displays a screen including the diagram to the user.
Status judgment system. In the state determination system according to claim 1 or 2,
The state determination device displays to the user a screen including a threshold value related to the index value, which constitutes a condition for determining the state, and changes the threshold value based on the user's operation on the screen. Set to
Status judgment system. In the state determination system according to claim 7,
The state determination device displays a plurality of diagrams created in response to a plurality of maintenance operations in parallel or superposed on the screen.
Status judgment system. A state determination method in a state determination system including a state determination device for determining the state of a rotating machine having a mechanical seal.
As a step executed by the state determination device,
A step of acquiring an effective value of an AE signal from an AE sensor installed in the rotating machine, a number of bearing characteristics of the mechanical seal, or a parameter for calculating the number of bearing characteristics.
A step of creating a diagram showing the relationship between the effective value of the AE signal and the number of bearing characteristics, and
A step of calculating an index value representing a change in the shape of the diagram to be determined with respect to the diagram in a normal state, and
A step of determining at least a normal or abnormal state regarding the state of the mechanical seal according to the index value and outputting the determination result.
A state determination method having. A state determination method in a state determination system including a state determination device for determining the state of a rotating machine having a mechanical seal.
As a step executed by the state determination device,
A step of acquiring an effective value of an AE signal from an AE sensor installed in the rotating machine, a rotation speed of the mechanical seal, or a parameter for calculating the rotation speed, and
A step of creating a diagram showing the relationship between the effective value of the AE signal and the rotation speed, and
A step of calculating an index value representing a change in the shape of the diagram to be determined with respect to the diagram in a normal state, and
A step of determining at least a normal or abnormal state regarding the state of the mechanical seal according to the index value and outputting the determination result.
A state determination method having.

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