Mechanical seal system

Abstract

A mechanical seal system according to the present disclosure comprises: a mechanical seal in a rotary machine provided with a rotary shaft and a casing surrounding the rotary shaft, said mechanical seal having a rotary seal ring provided on a rotary shaft so as to be capable of rotating integrally therewith and a stationary seal ring which is provided on the casing and on which the rotary seal ring slides, the sliding portions of the rotary seal ring and the stationary seal ring forming a seal between an internal region and an external region of the rotary machine, and being cooled and lubricated by a flushing fluid supplied to the internal region; a state detection unit that detects a state related to the mechanical seal in order to monitor the mechanical seal; and a control unit that, on the basis of a detection result from the state detection unit, executes operation state determination for determining whether or not the rotation machine is in operation.

Description

Mechanical Seal System

[0001] The present disclosure relates to a mechanical seal system. This application claims priority based on Japanese Application No. 2024-192602 filed on November 1, 2024, and incorporates all the descriptions set forth in the said Japanese application.

[0002] As a seal for the fluid to be sealed inside a rotating device, for example, a mechanical seal shown in Patent Document 1 is known. The mechanical seal of Patent Document 1 includes a stationary seal ring provided in the housing of the rotating device and a rotating seal ring provided on the rotating shaft of the rotating device and sliding against the stationary seal ring. The sliding portion between the rotating seal ring and the stationary seal ring is cooled and lubricated by a flushing fluid.

[0003] Japanese Patent Application Laid-Open No. 2021-060079

[0004] In recent years, there has been an increasing desire to accurately grasp the cooling state and lubrication state of the above mechanical seal using various sensing data. The present disclosure has been made in view of such circumstances, and an object thereof is to provide a mechanical seal system capable of accurately grasping the cooling state and lubrication state of the sliding portion of the mechanical seal.

[0005] (1) The mechanical seal system of the present disclosure is for a rotating device including a rotating shaft and a casing surrounding the rotating shaft, and has a rotating seal ring provided rotatably integrally with the rotating shaft and a stationary seal ring provided in the casing against which the rotating seal ring slides. The sliding portion of the rotating seal ring and the stationary seal ring seals between the in-machine region and the out-of-machine region of the rotating device, and a mechanical seal in which the sliding portion is cooled and lubricated by a flushing fluid supplied to the in-machine region, a state detection unit that detects a state related to the mechanical seal to monitor the mechanical seal, and a control unit that executes an operation state determination for determining whether or not the rotating device is in operation based on the detection result of the state detection unit.

[0006] According to the mechanical seal system described in (1) above, the control unit determines whether the rotating equipment is in operation based on the detection results of the state detection unit, which detects the state of the mechanical seal. Based on this determination, the mechanical seal can be monitored using sensing data detected only when the rotating equipment is in operation. As a result, sensing data detected when the rotating equipment is stopped is excluded, so the cooling and lubrication status of the sliding part of the mechanical seal during operation of the rotating equipment can be accurately grasped.

[0007] (2) From another perspective, the mechanical seal system of the present disclosure is a rotating machine having a rotating shaft and a casing surrounding the rotating shaft, and comprises a rotating sealing ring provided integrally rotatably on the rotating shaft and a stationary sealing ring provided on the casing on which the rotating sealing ring slides, wherein the sliding portions of the rotating sealing ring and the stationary sealing ring seal the space between the internal and external regions of the rotating machine, and the sliding portion is cooled and lubricated by a flushing fluid supplied to the internal region, and comprises a first temperature detection unit for detecting a first temperature of the flushing fluid before cooling the sliding portion, a second temperature detection unit for detecting a second temperature of the flushing fluid after cooling the sliding portion, and a control unit for determining the cooling state of the sliding portion based on the temperature difference between the detected first and second temperatures.

[0008] According to the mechanical seal system described in (2) above, the control unit determines the cooling state of the sliding portion of the mechanical seal based on the temperature difference between the first temperature of the flushing fluid before cooling and the second temperature after cooling, as detected by the first temperature detection unit and the second temperature detection unit. For example, if the temperature difference is greater than or equal to a threshold, it can be said that heat generation in the sliding portion is increasing due to frictional heat or the like, and that the cooling of the sliding portion is insufficient. If the temperature difference is less than the threshold, it can be said that heat generation in the sliding portion is kept low, and that the cooling of the sliding portion is normal. Therefore, the cooling state of the sliding portion of the mechanical seal can be accurately determined based on the temperature difference.

[0009] (3) From another perspective, the mechanical seal system of the present disclosure is a rotating machine having a rotating shaft and a casing surrounding the rotating shaft, and comprises a rotating sealing ring provided integrally rotatably on the rotating shaft and a stationary sealing ring provided on the casing on which the rotating sealing ring slides, wherein the sliding portions of the rotating sealing ring and the stationary sealing ring seal the space between the internal and external regions of the rotating machine, and the sliding portion is cooled and lubricated by a flushing fluid supplied to the internal region, and comprises a first temperature detection unit for detecting a first temperature of the flushing fluid before cooling the sliding portion, a second temperature detection unit for detecting a second temperature of the flushing fluid after cooling the sliding portion, and a control unit for determining the lubrication state of the sliding portion based on the temperature difference between the detected first and second temperatures.

[0010] According to the mechanical seal system described in (3) above, the control unit determines the lubrication state of the sliding portion of the mechanical seal based on the temperature difference between the first temperature of the flushing fluid before cooling and the second temperature after cooling, as detected by the first temperature detection unit and the second temperature detection unit. For example, if the temperature difference is below a threshold, it can be said that the lubrication state of the sliding portion is such that a large amount of flushing fluid leaks out to the outside area. If the temperature difference is greater than the threshold, it can be said that the lubrication state of the sliding portion is such that a small amount of flushing fluid leaks out to the outside area. Therefore, the lubrication state of the sliding portion of the mechanical seal can be accurately determined based on the temperature difference.

[0011] (4) The mechanical seal system described in (1) comprises a first temperature detection unit for detecting a first temperature of the flushing fluid before cooling the sliding portion, and a second temperature detection unit for detecting a second temperature of the flushing fluid after cooling the sliding portion. The control unit preferably determines the cooling state of the sliding portion based on the temperature difference between the first and second temperatures detected by the first and second temperature detection units, only when the determination result of the operating state determination is positive. In this case, the control unit determines the cooling state of the sliding portion of the mechanical seal based on the temperature difference between the first and second temperatures detected only when the rotating equipment is in operation. This excludes the temperature difference when the rotating equipment is stopped, making it possible to grasp the cooling state of the sliding portion of the mechanical seal with greater accuracy while the rotating equipment is in operation.

[0012] (5) In the mechanical seal system of (2) or (4) above, the control unit determines the cooling state based on a comparison of the temperature difference with a threshold value, and it is preferable that the threshold value is set to a different value depending on the type of flushing fluid. In this case, the cooling state of the sliding portion of the mechanical seal can be grasped with even greater accuracy.

[0013] (6) The mechanical seal system of (1) or (2) comprises a first temperature detection unit for detecting a first temperature of the flushing fluid before cooling the sliding portion, and a second temperature detection unit for detecting a second temperature of the flushing fluid after cooling the sliding portion, and the control unit preferably determines the lubrication state of the sliding portion based on the temperature difference between the first temperature and the second temperature detected by the first temperature detection unit and the second temperature detection unit, only when the determination result of the operating state determination is positive. In this case, the control unit determines the lubrication state of the sliding portion of the mechanical seal based on the temperature difference between the first temperature and the second temperature detected only when the rotating equipment is in operation. As a result the temperature difference when the rotating equipment is stopped is excluded, the lubrication state of the sliding portion of the mechanical seal during the operation of the rotating equipment can be grasped with even greater accuracy.

[0014] (7) In the mechanical seal system of (3) or (6) above, the control unit preferably determines the amount of flushing fluid leakage from the sliding portion to the outside region based on the temperature difference as a determination of the lubrication state. In this case, the control unit determines the amount of flushing fluid leakage from the sliding portion of the mechanical seal to the outside region based on the temperature difference between the detected first temperature and the second temperature. This makes it possible to accurately determine the amount of flushing fluid leakage.

[0015] (8) In any of the mechanical seal systems described in (3), (6), and (7), the control unit preferably determines the degree of leakage of the flushing fluid from the sliding portion to the external region based on the temperature difference as a determination of the lubrication state. In this case, the control unit determines the degree of leakage of the flushing fluid from the sliding portion of the mechanical seal to the external region based on the temperature difference between the detected first temperature and the second temperature. This makes it possible to accurately determine the degree of leakage of the flushing fluid.

[0016] (9) In any of the mechanical seal systems described in (3), (6) to (8) above, the control unit preferably determines the trend of the lubrication state based on the temperature difference as the determination of the lubrication state. In this case, the control unit determines the trend of the lubrication state of the sliding portion of the mechanical seal based on the temperature difference between the detected first temperature and the second temperature. This makes it possible to accurately grasp the trend of the lubrication state.

[0017] (10) In any of the mechanical seal systems described in (3), (6) to (9) above, the control unit preferably determines whether the lubrication state is stable based on the temperature difference as the determination of the lubrication state. In this case, the control unit determines whether the lubrication state of the sliding portion of the mechanical seal is stable based on the temperature difference between the detected first temperature and the second temperature. This makes it possible to accurately determine whether the lubrication state is stable or not.

[0018] (11) In any of the mechanical seal systems described in (3), (6) to (10) above, the control unit preferably determines the degree of instability of the lubrication state based on the temperature difference as a determination of the lubrication state. In this case, the control unit determines the degree of instability of the lubrication state at the sliding portion of the mechanical seal based on the temperature difference between the detected first temperature and the second temperature. This makes it possible to accurately grasp the degree of instability of the lubrication state.

[0019] The mechanical seal system disclosed herein allows for accurate monitoring of the cooling and lubrication conditions of the sliding portion of the mechanical seal.

[0020] This is a cross-sectional view showing a mechanical seal system according to an embodiment of the present disclosure. This is an enlarged cross-sectional view showing a mechanical seal. This is a flowchart showing the execution order of multiple determinations by the control unit. This is a flowchart showing an example of an operating state determination performed by the control unit. This is a graph showing an example of the display of operating state information on the display unit of the monitoring device. This is a flowchart showing an example of a cooling state determination performed by the control unit. This is a graph showing an example of the display of cooling state information on the display unit of the monitoring device. This is a flowchart showing an example of a lubrication state determination performed by the control unit. This is a graph showing an example of the display of lubrication state information on the display unit of the monitoring device. This is a flowchart showing a first modified example of a lubrication state determination performed by the control unit. This is an explanatory diagram of the first modified example. This is a graph showing an example of the display of lubrication state information of the first modified example on the display unit of the monitoring device. This is a flowchart showing a second modified example of a lubrication state determination performed by the control unit. This is an explanatory diagram of the second modified example. This is a graph showing an example of the display of lubrication state information of the second modified example on the display unit of the monitoring device. This is a flowchart showing a third modified example of a lubrication state determination performed by the control unit. This is an explanatory diagram of the third modified example. This is a graph showing an example of the display of lubrication state information of the third modified example on the display unit of the monitoring device. This is a flowchart showing a fourth modified example of a lubrication state determination performed by the control unit. This is an explanatory diagram of the fourth modified example. This graph shows an example of the display of lubrication status information in the display unit of the monitoring device, representing a fourth modified example.

[0021] Next, preferred embodiments will be described with reference to the attached drawings. Figure 1 is a cross-sectional view showing a mechanical seal system 1 according to the first embodiment of the present disclosure. In Figure 1, the mechanical seal system 1 comprises a mechanical seal 2, a state detection unit 5, and a control unit 6. The mechanical seal 2 is provided on a rotating device 70 such as a pump and seals the fluid to be sealed (solvent, water, oil, etc.) inside the rotating device 70. The rotating device 70 comprises a rotating shaft 71 and a casing 72 surrounding the rotating shaft 71.

[0022] In this specification, "axial direction" refers to the direction along the axis X of the rotation axis 71. "Radial direction" refers to the direction perpendicular to the axis X of the rotation axis 71. "Circumferential direction" refers to the direction around the axis X of the rotation axis 71. For convenience, in this specification, the right side of Figure 1 (outside the machine) is referred to as one axial side, and the left side of Figure 1 (inside the machine) is referred to as the other axial side.

[0023] <Mechanical Seal> Figure 2 is an enlarged cross-sectional view showing the mechanical seal 2. In Figure 2, the mechanical seal 2 of this embodiment is a so-called inside-type mechanical seal in which an internal region A is formed on the radially outer side of its sliding portion (described later) where the fluid to be sealed is sealed. The mechanical seal 2 comprises a rotating unit 3 that is integrally rotatable on the rotating shaft 71 and a stationary unit 4 provided on the casing 72.

[0024] The rotating unit 3 comprises a first retainer 31, a drive pin 32, a drive collar 33, a spring 34, a second retainer 35, and a rotating sealing ring 36. The first retainer 31, the drive collar 33, the second retainer 35, and the rotating sealing ring 36 are all formed in an annular shape.

[0025] The first retainer 31 is fitted and fixed to the outer circumferential surface of the rotating shaft 71. Multiple drive pins 32 (only one is shown in Figure 1) pass through the first retainer 31 axially, spaced apart in the circumferential direction. The drive pins 32 are held so as to be movable in the axial direction relative to the first retainer 31.

[0026] The drive collar 33 is positioned at a distance from one side of the first retainer 31 in the axial direction. The drive collar 33 is fitted to the outer surface of the rotating shaft 71 so as to be movable in the axial direction. One end of the drive pin 32 in the axial direction is fixed (screwed) to the drive collar 33. As a result, the drive collar 33 is held to move in the axial direction relative to the first retainer 31 via the drive pin 32, and its relative rotation with respect to the first retainer 31 is restricted.

[0027] Multiple springs 34 (only one is shown in Figure 1) are provided between the drive collar 33 and the first retainer 31 at intervals in the circumferential direction. The springs 34 bias the drive collar 33 axially toward one side relative to the first retainer 31 by their elastic force.

[0028] The second retainer 35 is positioned adjacent to one axial side of the drive collar 33. The second retainer 35 is fitted to the outer circumferential surface of the rotating shaft 71 so as to be axially movable. The other axial end of the second retainer 35 is fixed to the drive collar 33. As a result, the second retainer 35 is held to be axially movable relative to the rotating shaft 71 together with the drive collar 33, and its relative rotation with respect to the drive collar 33 is restricted. The space between the inner circumferential surface of the second retainer 35 and the outer circumferential surface of the rotating shaft 71 is sealed (secondary seal) by an O-ring 37.

[0029] The rotating sealing ring 36 is fixed to one axial end of the second retainer 35. A sealing surface 36a is formed on the axial end face of the rotating sealing ring 36. The rotating sealing ring 36 is biased axially to one side via the drive collar 33 and the second retainer 35 by the elastic force of the spring 34.

[0030] In Figures 1 and 2, the stationary unit 4 comprises a seal case 41 and a stationary sealing ring 42. Both the seal case 41 and the stationary sealing ring 42 are formed in an annular shape. The seal case 41 is fixed to one axial end face of the casing 72. The stationary sealing ring 42 is fitted and fixed to the inner circumferential surface of the seal case 41. The space between the outer circumferential surface of the stationary sealing ring 42 and the inner circumferential surface of the seal case 41 is sealed (secondary seal) by an O-ring 43.

[0031] A sealing surface 42a is formed on the other axial end face of the stationary sealing ring 42. The sealing surface 36a of the rotating sealing ring 36 slides on the sealing surface 42a of the stationary sealing ring 42. The sliding portions (both sealing surfaces 36a and 42a) of the rotating sealing ring 36 and the stationary sealing ring 42 form an internal region A and an external region B in the rotating device 70. Hereinafter, the sliding portions of the rotating sealing ring 36 and the stationary sealing ring 42 will also be referred to as sliding portions 36a and 42a.

[0032] Internal region A is the region where the fluid to be sealed is sealed, and is formed radially outward from the sliding portions 36a and 42a within the casing 72. External region B is the region that communicates with the atmosphere, and is formed radially inward from the sliding portions 36a and 42a. The space between internal region A and external region B is sealed by the sliding portions 36a and 42a.

[0033] In Figure 1, the sliding portions 36a and 42a of the mechanical seal 2 are cooled and lubricated by a flushing fluid. In this embodiment, the fluid to be sealed is used as the flushing fluid. Hereinafter, the flushing fluid before cooling the sliding portions 36a and 42a will also be referred to as the "flushing fluid before cooling." The flushing fluid after cooling the sliding portions 36a and 42a will also be referred to as the "flushing fluid after cooling."

[0034] A supply channel 44 is formed radially through the seal case 41 of the mechanical seal 2, supplying the flushing fluid before cooling to the internal region A. A pipe 10, through which the flushing fluid before cooling flows, is connected to the supply channel 44. The flushing fluid before cooling is supplied to the internal region A by passing through the pipe 10 and the supply channel 44.

[0035] The flushing fluid enters the sliding parts 36a and 42a (between the sealing surfaces 36a and 42a) from the internal region A, thereby cooling and lubricating the sliding parts 36a and 42a. At the same time, the sliding parts 36a and 42a are cooled and lubricated while a small amount of flushing fluid leaks from the sliding parts 36a and 42a to the external region B. The heat generated by the sliding of the sliding parts 36a and 42a is dissipated to the area around the rotating sealing ring 36 and the stationary sealing ring 42, causing the temperature around them to rise. By supplying the flushing fluid to the internal region A, the temperature rise around the rotating sealing ring 36 and the stationary sealing ring 42 can be kept constant.

[0036] The seal case 41 has a mounting hole 45 that extends radially through it, and a second temperature detection unit 52, which will be described later, is provided in the hole. The mounting hole 45 is located circumferentially away from the supply channel 44 and radially outward from the sliding portions 36a and 42a. The mounting hole 45 may also be located axially away from the supply channel 44.

[0037] <State Detection Unit> The state detection unit 5 detects the state of the mechanical seal 2 in order to monitor the mechanical seal 2. The mechanical seal system 1 of this embodiment includes a plurality of state detection units 5 that detect various states of the mechanical seal 2. The plurality of state detection units 5 include a first temperature detection unit 51, a second temperature detection unit 52, a pressure detection unit 53, and a vibration detection unit 54.

[0038] The first temperature detection unit 51 and the second temperature detection unit 52 are, for example, sheathed thermocouples, and detect the temperature of the flushing fluid inside the mechanical seal 2 at predetermined intervals. The first temperature detection unit 51 is provided in the piping 10 connected to the supply channel 44. The first temperature detection unit 51 detects a first temperature, which is the temperature of the flushing fluid flowing inside the piping 10 before cooling. The second temperature detection unit 52 is inserted and mounted in the mounting hole 45 of the seal case 41. The second temperature detection unit 52 detects a second temperature, which is the temperature of the flushing fluid after cooling in the internal region A.

[0039] The pressure detection unit 53 is, for example, a pressure sensor and is installed in the piping 10 connected to the supply channel 44. The pressure detection unit 53 detects the pressure inside the piping 10 at predetermined intervals. The pressure inside the piping 10 is approximately the same as the pressure in the internal region A. Therefore, the pressure detection unit 53 in this embodiment indirectly detects the pressure in the internal region A of the mechanical seal 2. Alternatively, the pressure detection unit 53 may directly detect the pressure in the internal region A.

[0040] The vibration detection unit 54 is, for example, an acceleration sensor and is provided on the outer circumferential surface of the casing 72. The vibration detection unit 54 detects vibrations of the mechanical seal 2 that propagate to the outer circumferential surface of the casing 72 at predetermined intervals. Although the vibration detection unit 54 directly detects vibrations of the mechanical seal 2, it may also detect vibrations of other components of the rotating equipment 70 (such as bearings or drive mechanisms) in order to indirectly detect vibrations of the mechanical seal 2.

[0041] The state detection unit 5 is not limited to this embodiment. For example, the state detection unit 5 may include at least one detection unit from among the first temperature detection unit 51, the second temperature detection unit 52, the pressure detection unit 53, and the vibration detection unit 54. In addition, the state detection unit 5 may include at least one acoustic sensor, AE (Acoustic Emission) sensor, flow sensor, torque sensor, current sensor, voltage sensor, power sensor, camera, etc., in addition to or instead of these detection units 51, 52, 53, and 54.

[0042] The acoustic sensor detects vibration noise generated at the sliding portions 36a and 42a of the mechanical seal 2. The AE sensor detects the state of AE waves generated by vibration, deformation, or fracture phenomena of the mechanical seal 2. The flow sensor detects the flow rate of the flushing fluid inside the mechanical seal 2. The torque sensor detects the rotational torque transmitted from the rotating shaft 71 to the rotating unit 3 of the mechanical seal 2.

[0043] The current sensor, voltage sensor, and power sensor detect the current, voltage, and power of the electricity supplied to, for example, a motor that rotationally drives the rotary shaft 71. The rotational torque transmitted from the motor to the rotary unit 3 via the rotary shaft 71 appears as the current, voltage, and power of the electricity supplied to the motor. Therefore, the current sensor, voltage sensor, and power sensor indirectly detect the rotational torque transmitted to the rotary unit 3 of the mechanical seal 2.

[0044] The camera images vibrations of the casing 72, rotation of the rotary shaft 71, etc., and by performing image processing on the captured images, detects leakage of the flushing fluid from the sliding portions 36a, 42a of the mechanical seal 2 to the outside area B.

[0045] <Control Unit> The control unit 6 is provided on the outer peripheral surface of the casing 72. The control unit 6 of the present embodiment is provided integrally with the vibration detection unit 54. The control unit 6 includes a control unit 61 that performs predetermined processing based on the detection results of the state detection unit 5, and a communication unit 62 that transmits predetermined information to the outside. Note that the control unit 6 may be separate from the vibration detection unit 54.

[0046] The control unit 61 is configured to include a computer having a CPU and a storage device, etc. Each function of the control unit 61 is exhibited by the control program stored in the storage device of the computer being executed by the CPU. The signal line 51a of the first temperature detection unit 51, the signal line 52a of the second temperature detection unit 52, the signal line 53a of the pressure detection unit 53, and the vibration detection unit 54 are connected to the control unit 61.

[0047] The detection results of the first temperature detection unit 51, the second temperature detection unit 52, the pressure detection unit 53, and the vibration detection unit 54 are input to the control unit 61. The control unit 61 executes a plurality of determinations respectively according to the control program based on the input detection results. Details of each of these determinations will be described later.

[0048] The communication unit 62 is connected to the control unit 61. The communication unit 62 has a function of wirelessly or wiredly transmitting and receiving predetermined information to / from, for example, a monitoring device (not shown) that monitors the mechanical seal 2 at a remote location away from the rotating device 70. When receiving a command transmitted from the control unit 61 to the monitoring device, the communication unit 62 transmits the predetermined information acquired from the control unit 61 to the monitoring device wirelessly or wiredly. The monitoring device includes a display unit such as a display (not shown), and visualizes and displays the predetermined information received from the communication unit 62 on the display unit.

[0049] <Multiple determination execution order> Figure 3 is a flowchart showing the execution order of multiple determinations by the control unit 61. In Figure 3, first, the control unit 61 executes an operation state determination to determine whether the rotating device 70 is in operation based on the detection result of the state detection unit 5 (step ST1). If the determination result of the operation state determination is negative (in the case of "No" in step ST2), that is, if it is determined that the rotating device 70 is not in operation, the control unit 61 ends the process without performing other determinations.

[0050] On the other hand, if the determination result of the operation state determination is positive (in the case of "Yes" in step ST2), that is, if it is determined that the rotating device 70 is in operation, the control unit 61 executes a cooling state determination (step ST3). As the cooling state determination, the control unit 61 determines the cooling state of the sliding portions 36a, 42a of the mechanical seal 2 based on the detection results of the first temperature detection unit 51 and the second temperature detection unit 52.

[0051] Next, the control unit 61 executes a lubrication state determination to determine the lubrication state of the sliding portions 36a, 42a of the mechanical seal 2 based on the detection results of the first temperature detection unit 51 and the second temperature detection unit 52 (step ST4).

[0052] As described above, the cooling state determination and the lubrication state determination are executed only when the determination result of the operation state determination is positive. Note that the order of the cooling state determination and the lubrication state determination may be reversed. Details of each determination will be described below.

[0053] <Determination of Operating State> Figure 4 is a flowchart showing an example of the determination of the operating state performed by the control unit 61. In Figure 4, first, the control unit 61 determines whether the detection data input at predetermined intervals from one or more of the detection units, including the first temperature detection unit 51, the second temperature detection unit 52, the pressure detection unit 53, and the vibration detection unit 54, is above (or below) a threshold. In this embodiment, the control unit 61 determines whether the detection data input at predetermined intervals from the vibration detection unit 54 is above the threshold Th1 (step ST11).

[0054] The threshold Th1 is set to an arbitrary value for each of the detection units 51, 52, 53, and 54. In addition to an arbitrary value, the threshold Th1 may be automatically set based on the average value of multiple detection data, or it may be set based on the rated operating value of the rotating equipment 70. For example, the threshold Th1 may be set to the average value or half of the rated operating value.

[0055] If the determination result in step ST11 is positive (if "Yes" is obtained in step ST11), the control unit 61 determines that the rotating equipment 70 is in operation (step ST12). Then, the control unit 61 adds a first flag indicating that the rotating equipment 70 is in operation to the operating status information S1, which includes the detection data and the detection time of the data that were determined in step ST11 (step ST13).

[0056] On the other hand, if the determination result in step ST11 is negative (if "No" is obtained in step ST11), the control unit 61 determines that the rotating equipment 70 is not in operation (step ST14). Then, the control unit 61 adds a second flag to the operating status information S1, which includes the detection data and detection time of the object of determination in step ST11, indicating that the rotating equipment 70 is stopped (step ST15).

[0057] Next, the control unit 61 outputs a transmission command to the communication unit 62 to transmit the operating status information S1 to which the first or second flag has been added (step ST16), and ends the operating status determination. As described above, at predetermined intervals, the control unit 61 determines the operating status of the rotating equipment 70 based on the detection data input from the vibration detection unit 54 and outputs a transmission command for the operating status information S1 to the communication unit 62.

[0058] The communication unit 62 transmits operating status information S1 to the monitoring device at predetermined intervals based on a transmission command from the control unit 61. The monitoring device displays the operating status information S1 received at predetermined intervals on its display unit.

[0059] Figure 5 is a graph showing an example of the display of operating status information S1 on the display unit of the monitoring device. As shown in Figure 5, the monitoring device displays a graph that visualizes the changes in the operating status of the rotating equipment 70 over time, based on the detected data (in this case, amplitude), detection time, and flags included in the operating status information S1.

[0060] The determination of the operating state is not limited to this embodiment. For example, in the determination in step ST11, the control unit 61 may determine that the rotating equipment 70 is in operation if a predetermined number of detection data among a plurality of detection data input at predetermined time intervals are all above a threshold. In this case, it is possible to reduce misdetermination due to sudden fluctuations in detection data.

[0061] Furthermore, although the detection data of the vibration detection unit 54 is used in the determination in step ST11, the detection data of the first temperature detection unit 51, the second temperature detection unit 52, or the pressure detection unit 53 may be used, or the detection data of two or more of these detection units 51, 52, 53, and 54 may be used.

[0062] <Cooling State Determination> Figure 6 is a flowchart showing an example of cooling state determination performed by the control unit 61. In Figure 6, in the cooling state determination of this embodiment, the control unit 61 determines whether the cooling of the sliding portions 36a and 42a of the mechanical seal 2 is normal or insufficient based on a comparison of the temperature difference ΔT (described later) and its threshold Th2. The details are described below.

[0063] First, the control unit 61 calculates the temperature difference ΔT between the first temperature and the second temperature, which are temperature detection data input from the first temperature detection unit 51 and the second temperature detection unit 52 at predetermined intervals (step ST31). Next, the control unit 61 determines whether the calculated temperature difference ΔT is less than the threshold Th2 (step ST32). The threshold Th2 is set to a different value depending on the type of flushing fluid. Note that the threshold Th2 may be a value calculated from machine learning based on design values ​​or experimental data.

[0064] If the temperature difference ΔT is less than the threshold Th2, the heat generation at the sliding parts 36a and 42a of the mechanical seal 2 is kept low, and the cooling of the sliding parts 36a and 42a is considered normal. On the other hand, if the temperature difference ΔT is greater than or equal to the threshold Th2, the heat generation at the sliding parts 36a and 42a increases due to frictional heat, etc., and the cooling of the sliding parts 36a and 42a is considered insufficient.

[0065] If the determination result in step ST32 is positive (if "Yes" is obtained in step ST32), the control unit 61 determines that the cooling of the sliding portions 36a and 42a of the mechanical seal 2 is normal (step ST33). Then, the control unit 61 adds a third flag indicating that the cooling is normal to the cooling state information S2, which includes the temperature difference ΔT that was the subject of determination in step ST32 and the detection time of the temperature detection data from which it was calculated (step ST34).

[0066] On the other hand, if the determination result in step ST32 is negative (if "No" is obtained in step ST32), the control unit 61 determines that the cooling of the sliding portions 36a and 42a of the mechanical seal 2 is insufficient (step ST35). The control unit 61 then adds a fourth flag indicating insufficient cooling to the cooling state information S2, which includes the temperature difference ΔT determined in step ST32 and the detection time of the temperature detection data from which it was calculated (step ST36).

[0067] Next, the control unit 61 outputs a transmission command to the communication unit 62 to transmit cooling state information S2 with a third or fourth flag added (step ST37), and ends the cooling state determination. Based on the above, at predetermined intervals, the control unit 61 determines the cooling state of the sliding parts 36a and 42a based on the temperature difference ΔT between the first temperature and the second temperature input from the first temperature detection unit 51 and the second temperature detection unit 52, and outputs a transmission command for cooling state information S2 to the communication unit 62.

[0068] The communication unit 62 transmits cooling status information S2 to the monitoring device at predetermined intervals based on a transmission command from the control unit 61. The monitoring device displays the received cooling status information S2 at predetermined intervals on its display unit.

[0069] Figure 7 is a graph showing an example of the display of cooling state information S2 on the display unit of the monitoring device. As shown in Figure 7, the monitoring device displays a graph that visualizes the change in the cooling state of the sliding parts 36a and 42a of the mechanical seal 2 over time, based on the temperature difference ΔT, detection time, and flag included in the cooling state information S2.

[0070] <Lubrication State Determination> Figure 8 is a flowchart showing an example of lubrication state determination performed by the control unit 61. In Figure 8, in the lubrication state determination of this embodiment, the control unit 61 determines the amount of flushing fluid leakage from the sliding portions 36a and 42a of the mechanical seal 2 to the external region B based on the temperature difference ΔT. The details are described below.

[0071] First, the control unit 61 calculates the temperature difference ΔT between the first temperature and the second temperature, which are temperature detection data input from the first temperature detection unit 51 and the second temperature detection unit 52 at predetermined intervals (step ST41). Next, the control unit 61 determines whether the calculated temperature difference ΔT is less than or equal to the threshold Th3 (step ST42). The threshold Th3 is set to a different value depending on the type of flushing fluid. For example, the threshold Th3 is set to half the design value of the temperature difference ΔT.

[0072] If the temperature difference ΔT is less than or equal to the threshold Th3, it can be said that the sliding parts 36a and 42a of the mechanical seal 2 are in a lubrication state in which a large amount of flushing fluid leaks into the external region B. On the other hand, if the temperature difference ΔT is greater than the threshold Th3, it can be said that the sliding parts 36a and 42a are in a lubrication state in which a small amount of flushing fluid leaks into the external region B.

[0073] If the determination result in step ST42 is positive (if "Yes" is obtained in step ST42), the control unit 61 determines that there is a large amount of flushing fluid leakage from the sliding parts 36a and 42a to the external area B (step ST43). Then, the control unit 61 adds a fifth flag indicating a large amount of leakage to the lubrication state information S3, which includes the temperature difference ΔT that was the subject of determination in step ST42 and the detection time of the temperature detection data from which it was calculated (step ST44).

[0074] On the other hand, if the determination result in step ST42 is negative (if "No" is obtained in step ST42), the control unit 61 determines that the amount of flushing fluid leaking from the sliding parts 36a and 42a to the external area B is small (step ST45). The control unit 61 then adds a sixth flag indicating that the amount of leakage is small to the lubrication state information S3, which includes the temperature difference ΔT that was the subject of determination in step ST42 and the detection time of the temperature detection data from which it was calculated (step ST46).

[0075] Next, the control unit 61 outputs a transmission command to the communication unit 62 to transmit lubrication state information S3 with the fifth or sixth flag added (step ST47), and ends the lubrication state determination. Based on the above, at predetermined intervals, the control unit 61 determines the amount of flushing fluid leakage from the sliding parts 36a and 42a based on the temperature difference ΔT between the first temperature and the second temperature input from the first temperature detection unit 51 and the second temperature detection unit 52, and outputs a transmission command for lubrication state information S3 to the communication unit 62.

[0076] The communication unit 62 transmits lubrication status information S3 to the monitoring device at predetermined intervals based on a transmission command from the control unit 61. The monitoring device displays the lubrication status information S3 received at predetermined intervals on its display unit.

[0077] Figure 9 is a graph showing an example of the display of lubrication status information S3 on the display unit of the monitoring device. As shown in Figure 9, the monitoring device displays a graph that visualizes the change in the lubrication status (amount of flushing fluid leakage) of the sliding parts 36a and 42a of the mechanical seal 2 over time, based on the temperature difference ΔT, detection time, and flag included in the lubrication status information S3.

[0078] <Effects> According to the mechanical seal system 1 of this embodiment, the control unit 61 determines whether or not the rotating equipment 70 is in operation based on the detection result of the vibration detection unit 54 that detects vibrations of the mechanical seal 2. Based on this determination result, the mechanical seal 2 can be monitored using the detection data detected by the first temperature detection unit 51 and the second temperature detection unit 52 only when the rotating equipment 70 is in operation. As a result, the detection data detected by the first temperature detection unit 51 and the second temperature detection unit 52 when the rotating equipment 70 is stopped is excluded, so the cooling state and lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 during operation of the rotating equipment 70 can be accurately grasped.

[0079] The control unit 61 determines the cooling state of the sliding portions 36a and 42a of the mechanical seal 2 based on the temperature difference ΔT between the first temperature of the flushing fluid before cooling and the second temperature after cooling, as detected by the first temperature detection unit 51 and the second temperature detection unit 52. Therefore, the cooling state of the sliding portions 36a and 42a of the mechanical seal 2 can be accurately determined based on the temperature difference ΔT.

[0080] The control unit 61 determines the lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 based on the temperature difference ΔT between the first temperature of the flushing fluid before cooling and the second temperature after cooling, as detected by the first temperature detection unit 51 and the second temperature detection unit 52. Therefore, the lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 can be accurately determined based on the temperature difference ΔT.

[0081] The control unit 61 determines the cooling state of the sliding portions 36a and 42a of the mechanical seal 2 based on the temperature difference ΔT between the first and second temperatures, which is detected only when the rotating equipment 70 is in operation. This excludes the temperature difference ΔT when the rotating equipment 70 is stopped, allowing for a more accurate understanding of the cooling state of the sliding portions 36a and 42a of the mechanical seal 2 while the rotating equipment 70 is in operation.

[0082] The threshold value Th2 used to determine the cooling state is set to a different value depending on the type of flushing fluid. This allows for a more accurate understanding of the cooling state of the sliding portions 36a and 42a of the mechanical seal 2.

[0083] The control unit 61 determines the lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 based on the temperature difference ΔT between the first and second temperatures, which is detected only when the rotating equipment 70 is in operation. This excludes the temperature difference ΔT when the rotating equipment 70 is stopped, allowing for a more accurate understanding of the lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 while the rotating equipment 70 is in operation.

[0084] The control unit 61 determines the amount of flushing fluid leakage from the sliding portions 36a and 42a of the mechanical seal 2 to the external region B based on the temperature difference ΔT between the detected first and second temperatures. This allows for accurate determination of the amount of flushing fluid leakage.

[0085] <First Modified Example of Lubrication State Determination> Figure 10 is a flowchart of the first modified example of lubrication state determination performed by the control unit 61. Figure 11 is an explanatory diagram of the first modified example. In Figures 10 and 11, the control unit 61 of this modified example determines the degree of leakage of flushing fluid from the sliding portions 36a and 42a of the mechanical seal 2 to the external region B based on the temperature difference ΔT. The details will be explained below.

[0086] First, the control unit 61 calculates the temperature difference ΔT between the first temperature and the second temperature, which are temperature detection data input from the first temperature detection unit 51 and the second temperature detection unit 52 at predetermined intervals (step ST51).

[0087] Next, the control unit 61 calculates a reference temperature difference ΔTs based on the calculated temperature difference ΔT (step ST52). The reference temperature difference ΔTs is calculated from the temperature difference ΔT in the steady-state operation of the rotating equipment 70. In this embodiment, for example, the control unit 61 considers the initial operation of the rotating equipment 70 as the steady-state operation, and calculates the average value of the temperature difference ΔT in the initial operation as the reference temperature difference ΔTs.

[0088] Next, the control unit 61 calculates the degree of flushing fluid leakage based on the calculated temperature difference ΔT and reference temperature difference ΔTs (step ST53). The degree of flushing fluid leakage is calculated, for example, by the following equation (1) (step ST53). Leakage degree = 1 - (temperature difference ΔT / reference temperature difference ΔTs) ... (1) In the above equation (1), the smaller the temperature difference ΔT, that is, the greater the amount of flushing fluid leakage, the greater the degree of flushing fluid leakage. This degree of leakage makes it possible to understand how much the amount of flushing fluid leakage has increased or decreased compared to steady-state operation.

[0089] Next, the control unit 61 determines whether the calculated leakage rate is greater than or equal to the threshold Th4 (step ST54). The threshold Th4 is set to, for example, any value. If the determination result in step ST54 is positive (if "Yes" is given in step ST54), the control unit 61 determines that the leakage rate of the flushing fluid from the sliding parts 36a and 42a to the external area B is high (step ST55). Then, the control unit 61 adds a seventh flag indicating a high leakage rate to the lubrication state information S4, which includes the leakage rate determined in step ST54 and the detection time of the temperature detection data from which it was calculated (step ST56).

[0090] On the other hand, if the determination result in step ST54 is negative (if "No" is obtained in step ST54), the control unit 61 determines that the degree of leakage of flushing fluid from the sliding parts 36a and 42a to the external area B is small (step ST57). The control unit 61 then adds an eighth flag indicating that the amount of leakage is small to the lubrication state information S4, which includes the degree of leakage determined in step ST54 and the detection time of the temperature detection data from which it was calculated (step ST58).

[0091] Next, the control unit 61 outputs a transmission command to the communication unit 62 to transmit lubrication status information S4 with the seventh or eighth flag added (step ST59), and ends the lubrication status determination. Based on the above, at predetermined intervals, the control unit 61 determines the degree of leakage of the flushing fluid based on the temperature difference ΔT between the first temperature and the second temperature input from the first temperature detection unit 51 and the second temperature detection unit 52, and outputs a transmission command for lubrication status information S4 to the communication unit 62.

[0092] The communication unit 62 transmits lubrication status information S4 to the monitoring device at predetermined intervals based on a transmission command from the control unit 61. The monitoring device displays the lubrication status information S4 received at predetermined intervals on its display unit.

[0093] Figure 12 is a graph showing an example of the display of lubrication status information S4 on the display unit of the monitoring device. As shown in Figure 12, the monitoring device displays a graph that visualizes the change in the lubrication state (degree of leakage of flushing fluid) of the sliding parts 36a and 42a of the mechanical seal 2 over time, based on the degree of leakage, detection time, and flag included in the lubrication status information S4. Note that in Figure 12, the degree of leakage is shown as a 100% converted value.

[0094] The determination of the degree of leakage is not limited to this modified example. For example, in the calculation of the reference temperature difference ΔTs in step ST52, any period in the initial stages of operation of the rotating equipment 70 (e.g., five temperature detection data points) may be considered as the steady-state operating condition. Alternatively, the variation in the standard deviation of the temperature detection data during operation of the rotating equipment 70 may be used as a reference, and if the temperature detection data shows a value below this standard for any period (e.g., five temperature detection data points), that period may be considered as the steady-state operating condition. Furthermore, in the calculation of the degree of leakage in step ST53, a calculation formula other than formula (1) may be used. For example, a calculation formula may be used in which the degree of leakage increases exponentially as the temperature difference ΔT becomes smaller.

[0095] According to the first modified example of lubrication state determination, the control unit 61 determines the degree of leakage of flushing fluid from the sliding portions 36a and 42a of the mechanical seal 2 to the external region B based on the temperature difference ΔT between the detected first and second temperatures. This allows for accurate determination of the degree of flushing fluid leakage.

[0096] <Second Modification of Lubrication State Determination> Figure 13 is a flowchart of a second modification of the lubrication state determination performed by the control unit 61. Figure 14 is an explanatory diagram of the second modification. In Figures 13 and 14, the control unit 61 of this modification determines the trend of the lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 based on the temperature difference ΔT. The details will be explained below.

[0097] First, the control unit 61 calculates the temperature difference ΔT between the first temperature and the second temperature, which are temperature detection data input from the first temperature detection unit 51 and the second temperature detection unit 52 at predetermined intervals (step ST60). Next, the control unit 61 calculates the slope of the time-series change of the temperature difference ΔT at regular intervals (step ST61). The slope of the time-series change of the temperature difference ΔT is calculated using, for example, the least squares method. Hereinafter, the slope of the time-series change of the temperature difference ΔT will also be simply referred to as the "slope".

[0098] Next, the control unit 61 determines the relationship between the slope calculated for each fixed period and a preset threshold (step ST62). In this determination, a positive threshold Th51 and a negative threshold Th52 are used as the thresholds. The positive threshold Th51 and the negative threshold Th52 are set to arbitrary values, for example.

[0099] Next, the control unit 61 determines the trend in the lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 based on the determination result of step ST62. If the slope is greater than the positive threshold Th51, the temperature difference ΔT is rapidly expanding, and the lubrication state is said to be on a downward trend. If the slope is less than or equal to the positive threshold Th51 and greater than or equal to the negative threshold Th52, the temperature difference ΔT is staying within the appropriate range, and the lubrication state is said to be normal. If the slope is less than the negative threshold Th52, the temperature difference ΔT is rapidly decreasing, and the lubrication state is said to be on a downward trend in flushing fluid leakage.

[0100] In step ST62, the control unit 61 determines that the slope is greater than a positive threshold Th51, and determines that the lubrication state of the sliding parts 36a and 42a is showing a tendency towards deterioration (step ST63). Then, the control unit 61 adds a ninth flag to the lubrication state information S5, which includes the slope determined in step ST62 and the detection time of the temperature detection data from which it was calculated, indicating that the lubrication state is showing a tendency towards deterioration (step ST64).

[0101] In step ST62, the control unit 61 determines that the lubrication state of the sliding parts 36a and 42a is normal if it determines that the inclination is less than or equal to the positive threshold Th51 and greater than or equal to the negative threshold Th52 (step ST65). Then, the control unit 61 adds a tenth flag indicating that the lubrication state is normal to the lubrication state information S5, which includes the inclination determined in step ST62 and the detection time of the temperature detection data from which it was calculated (step ST66).

[0102] In step ST62, if the control unit 61 determines that the inclination is less than a negative threshold Th52, it determines that the lubrication state of the sliding parts 36a and 42a is showing an increasing trend in flushing fluid leakage (step ST67). Then, the control unit 61 adds an eleventh flag to the lubrication state information S5, which includes the inclination determined in step ST62 and the detection time of the temperature detection data from which it was calculated, indicating that the lubrication state is showing an increasing trend in leakage (step ST68).

[0103] Next, the control unit 61 outputs a transmission command to the communication unit 62 to transmit lubrication status information S5 with the 9th, 10th, or 11th flag attached (step ST69), and ends the lubrication status determination. Based on the above, the control unit 61 calculates the slope of the time-series change of the temperature difference ΔT at regular intervals based on the temperature difference ΔT of the first temperature and the second temperature input from the first temperature detection unit 51 and the second temperature detection unit 52 at predetermined intervals. Then, the control unit 61 determines the trend of the lubrication status based on the calculated slope and outputs a transmission command for lubrication status information S5 to the communication unit 62.

[0104] The communication unit 62 transmits lubrication status information S5 to the monitoring device at regular intervals based on a transmission command from the control unit 61. The monitoring device displays the lubrication status information S5 received at regular intervals on its display unit.

[0105] Figure 15 is a graph showing an example of the display of lubrication status information S5 on the display unit of the monitoring device. As shown in Figure 15, the monitoring device displays a graph that visualizes the change in the trend of the lubrication status at the sliding parts 36a and 42a of the mechanical seal 2 over time, based on the slope of the time-series change of the temperature difference ΔT, the detection time, and the flag included in the lubrication status information S5.

[0106] According to a second modified example of lubrication state determination, the control unit 61 determines the trend of the lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 based on the temperature difference ΔT between the detected first temperature and the second temperature. This makes it possible to accurately grasp the trend of the lubrication state of the sliding portions 36a and 42a.

[0107] <Third Modification of Lubrication State Determination> Figure 16 is a flowchart showing a third modification of the lubrication state determination performed by the control unit 61. Figure 17 is an explanatory diagram of the third modification. In Figures 16 and 17, the control unit 61 of this modification determines whether the lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 is stable based on the temperature difference ΔT. The details will be explained below.

[0108] First, the control unit 61 calculates the temperature difference ΔT between the first temperature and the second temperature, which are temperature detection data input from the first temperature detection unit 51 and the second temperature detection unit 52 at predetermined intervals (step ST71). Next, the control unit 61 calculates the variation in the temperature difference ΔT at regular intervals (step ST72). The variation in the temperature difference ΔT is calculated using, for example, the standard deviation or variance.

[0109] Next, the control unit 61 determines whether the slope calculated for each fixed period is greater than or equal to the threshold Th6 (step ST73). The threshold Th6 is set to, for example, an arbitrary value. If the determination result in step ST73 is positive (if "Yes" is given in step ST73), the control unit 61 determines that the lubrication state of the sliding parts 36a and 42a is unstable (unstable lubrication) (step ST74). Then, the control unit 61 adds a 12th flag indicating that the lubrication state is unstable to the lubrication state information S6, which includes the variation in the temperature difference ΔT that is the subject of determination in step ST73, and the detection time of the temperature detection data from which it is calculated (step ST75).

[0110] On the other hand, if the determination result in step ST73 is negative (if "No" is obtained in step ST73), the control unit 61 determines that the lubrication state of the sliding parts 36a and 42a is stable (stable lubrication) (step ST76). Then, the control unit 61 adds a 13th flag indicating that the lubrication state is stable to the lubrication state information S6, which includes the variation in the temperature difference ΔT that is the subject of determination in step ST73, and the detection time of the temperature detection data from which it is calculated (step ST77).

[0111] Next, the control unit 61 outputs a transmission command to the communication unit 62 to transmit lubrication status information S6 with the 12th or 13th flag attached (step ST78), and ends the lubrication status determination. Based on the above, the control unit 61 calculates the variation in the temperature difference ΔT at regular intervals based on the temperature difference ΔT between the first temperature and the second temperature input from the first temperature detection unit 51 and the second temperature detection unit 52 at predetermined intervals. Then, based on the calculated variation, the control unit 61 determines whether or not the lubrication state is stable and outputs a transmission command for lubrication status information S6 to the communication unit 62.

[0112] The communication unit 62 transmits lubrication status information S6 to the monitoring device at regular intervals based on a transmission command from the control unit 61. The monitoring device displays the lubrication status information S6 received at regular intervals on its display unit.

[0113] Figure 18 is a graph showing an example of the display of lubrication status information S6 on the display unit of the monitoring device. As shown in Figure 18, the monitoring device displays a graph that visualizes the change in the variation of the temperature difference ΔT at the sliding parts 36a and 42a of the mechanical seal 2 over time, based on the variation in temperature difference ΔT, detection time, and flag included in the lubrication status information S6.

[0114] The determination of whether the lubrication state is stable is not limited to this modified example. For example, instead of the variation in the temperature difference ΔT, an index representing the time-series change in the temperature difference ΔT, such as kurtosis, may be used.

[0115] According to a third modified example of lubrication state determination, the control unit 61 determines whether the lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 is stable based on the temperature difference ΔT between the detected first temperature and second temperature. This makes it possible to accurately determine whether the lubrication state of the sliding portions 36a and 42a is stable.

[0116] <Fourth Modification of Lubrication State Determination> Figure 19 is a flowchart of the fourth modification of lubrication state determination performed by the control unit 61. Figure 20 is an explanatory diagram of the fourth modification. In Figures 19 and 20, the control unit 61 of this modification determines the degree of instability of the lubrication state of the sliding portions 36a and 42a of the mechanical seal 2 based on the temperature difference ΔT. The details will be explained below.

[0117] First, the control unit 61 calculates the temperature difference ΔT between the first temperature and the second temperature, which are temperature detection data input from the first temperature detection unit 51 and the second temperature detection unit 52 at predetermined intervals (step ST80).

[0118] Next, the control unit 61 calculates the reference variation of the calculated temperature difference ΔT (step ST81). In this modified example, the control unit 61 considers the initial operation of the rotating equipment 70 as a steady-state operation, and calculates the variation of the temperature difference ΔT at the initial operation as the reference variation of the temperature difference ΔT. The variation of the temperature difference ΔT is calculated using, for example, the standard deviation or variance.

[0119] Next, the control unit 61 calculates the variation in the temperature difference ΔT at regular intervals (step ST82). Then, the control unit 61 calculates the degree of instability of the lubrication state of the sliding parts 36a and 42a based on the variation in the temperature difference ΔT calculated for each regular period (hereinafter also referred to as "period variation") and the reference variation in the temperature difference ΔT in the steady-state operation (step ST83). The degree of instability of the lubrication state is calculated, for example, by the following equation (2): Degree of instability of lubrication state = period variation / reference variation ... (2) In the above equation (2), the larger the period variation, the greater the degree of instability of the lubrication state.

[0120] Next, the control unit 61 determines whether the calculated degree of instability of the lubrication state is greater than or equal to the threshold Th7 (step ST84). The threshold Th7 is set to, for example, any value. If the determination result in step ST84 is positive (if "Yes" is given in step ST84), the control unit 61 determines that the degree of instability of the lubrication state of the sliding parts 36a and 42a is high (step ST85). Then, the control unit 61 adds a 14th flag indicating that the degree of instability of the lubrication state is high to the lubrication state information S7, which includes the degree of instability of the lubrication state that was the subject of determination in step ST84, and the detection time of the temperature detection data from which it was calculated (step ST86).

[0121] On the other hand, if the determination result in step ST84 is positive (if "No" is obtained in step ST84), the control unit 61 determines that the degree of instability in the lubrication state of the sliding parts 36a and 42a is small (step ST87). The control unit 61 then adds a 15th flag indicating that the degree of instability in the lubrication state is small to the lubrication state information S7, which includes the degree of instability in the lubrication state that was the subject of determination in step ST84, and the detection time of the temperature detection data from which it was calculated (step ST88).

[0122] Next, the control unit 61 outputs a transmission command to the communication unit 62 to transmit lubrication state information S7 with the 14th or 15th flag attached (step ST89), and ends the lubrication state determination. Based on the above, the control unit 61 calculates the period variation of the temperature difference ΔT at regular intervals based on the temperature difference ΔT between the first temperature and the second temperature input from the first temperature detection unit 51 and the second temperature detection unit 52 at predetermined intervals. Then, the control unit 61 determines the degree of instability of the lubrication state based on the calculated period variation and outputs a transmission command for lubrication state information S7 to the communication unit 62.

[0123] The communication unit 62 transmits lubrication status information S7 to the monitoring device at regular intervals based on a transmission command from the control unit 61. The monitoring device displays the lubrication status information S7 received at regular intervals on its display unit.

[0124] Figure 21 is a graph showing an example of the display of lubrication state information S7 on the display unit of the monitoring device. As shown in Figure 21, the monitoring device displays a graph that visualizes the change in the degree of instability of the lubrication state at the sliding parts 36a and 42a of the mechanical seal 2 over time, based on the degree of instability of the lubrication state, the detection time, and the flag included in the lubrication state information S7.

[0125] The determination of the degree of instability of the lubrication state is not limited to this modified example. For example, instead of the variation in the temperature difference ΔT, an index representing the time-series change in the temperature difference ΔT, such as kurtosis, may be used. Also, the calculation of the degree of instability in step ST84 may be performed using a calculation formula other than the above formula (2). For example, a calculation formula may be used in which the degree of instability increases exponentially as the period variation of the temperature difference ΔT decreases.

[0126] According to the fourth modified example of lubrication state determination, the control unit 61 determines the degree of instability of the lubrication state at the sliding portions 36a and 42a of the mechanical seal 2 based on the temperature difference ΔT between the detected first temperature and the second temperature. This makes it possible to accurately grasp the degree of instability of the lubrication state at the sliding portions 36a and 42a.

[0127] <Other> The control unit 61 may perform smoothing processing of the detected data in advance before performing the operation state determination, cooling state determination, or lubrication state determination. In this case, errors originating from the detection units 51, 52, 53, and 54 can be removed in advance, thereby stabilizing the determination results of each determination. Alternatively, the control unit 61 may perform the operation state determination, cooling state determination, or lubrication state determination based on detected data sampled at regular intervals in advance. In this case, the number of detected data used in each determination can be reduced, thereby shortening the processing time for each determination.

[0128] The control unit 61 performs the cooling state determination and the lubrication state determination only when the result of the operating state determination is positive, but it may perform at least one of the cooling state determination and the lubrication state determination regardless of the result of the operating state determination. As the lubrication state determination, the control unit 61 may perform the determination of the amount of leakage of the flushing fluid and two or more determinations from the first to fourth modified examples described above.

[0129] The control unit 61 may be located in a web application server or the monitoring device described above, installed in a remote location away from the rotating equipment 70, in addition to the control unit 6. In that case, the communication unit 62 may transmit the detection results of the state detection unit 5 to the control unit 61 wirelessly or via a wired connection. If the control unit 61 is located in a web application server, the control unit 61 has a storage device that stores the web application program, and each determination may be performed using the program. The control unit 61 may then have the web application display or notify the information S1, S2, S3, S4, S5, S6, S7 corresponding to the determination results of each determination.

[0130] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims, not in the sense described above, and is intended to include all modifications within the meaning and scope of the equivalents of the claims.

[0131] 1 Mechanical seal system 2 Mechanical seal 3 Stationary unit 4 Pressure regulating valve 36 Rotating sealing ring 36a, 42a Sliding part 42 Stationary sealing ring 51 First temperature detection unit 52 Second temperature detection unit 61 Control unit 70 Rotating equipment 71 Rotating shaft 72 Casing A Internal area B External area Th2 Threshold ΔT Temperature difference

Claims

1. A mechanical seal system for a rotating machine comprising a rotating shaft and a casing surrounding the rotating shaft, the mechanical seal comprising: a rotating sealing ring integrally rotatably mounted on the rotating shaft; and a stationary sealing ring provided on the casing on which the rotating sealing ring slides, wherein the sliding portions of the rotating sealing ring and the stationary sealing ring seal the space between the internal and external regions of the rotating machine, and the sliding portions are cooled and lubricated by a flushing fluid supplied to the internal region; a state detection unit for detecting the state of the mechanical seal in order to monitor the mechanical seal; and a control unit that performs an operating state determination to determine whether or not the rotating machine is in operation based on the detection result of the state detection unit.

2. A mechanical seal system for a rotating machine comprising a rotating shaft and a casing surrounding the rotating shaft, comprising: a rotating sealing ring integrally rotatably mounted on the rotating shaft; and a stationary sealing ring provided on the casing on which the rotating sealing ring slides, wherein the sliding portions of the rotating sealing ring and the stationary sealing ring seal the space between the internal and external regions of the rotating machine, and the sliding portion is cooled and lubricated by a flushing fluid supplied to the internal region; a first temperature detection unit for detecting a first temperature of the flushing fluid before cooling the sliding portion; a second temperature detection unit for detecting a second temperature of the flushing fluid after cooling the sliding portion; and a control unit for determining the cooling state of the sliding portion based on the temperature difference between the detected first and second temperatures.

3. A mechanical seal system for a rotating machine comprising a rotating shaft and a casing surrounding the rotating shaft, comprising: a rotating sealing ring integrally rotatably mounted on the rotating shaft; a stationary sealing ring provided on the casing on which the rotating sealing ring slides, wherein the sliding portions of the rotating sealing ring and the stationary sealing ring seal the space between the internal and external regions of the rotating machine, and the sliding portion is cooled and lubricated by a flushing fluid supplied to the internal region; a first temperature detection unit for detecting a first temperature of the flushing fluid before cooling the sliding portion; a second temperature detection unit for detecting a second temperature of the flushing fluid after cooling the sliding portion; and a control unit for determining the lubrication state of the sliding portion based on the temperature difference between the detected first and second temperatures.

4. The mechanical seal system according to claim 1, comprising: a first temperature detection unit for detecting a first temperature of the flushing fluid before cooling the sliding portion; and a second temperature detection unit for detecting a second temperature of the flushing fluid after cooling the sliding portion, wherein the control unit determines the cooling state of the sliding portion based on the temperature difference between the first temperature and the second temperature detected by the first temperature detection unit and the second temperature detection unit, only when the determination result of the operating state determination is positive.

5. The mechanical seal system according to claim 2 or 4, wherein the control unit determines the cooling state based on a comparison of the temperature difference with a threshold value, and the threshold value is set to a different value depending on the type of flushing fluid.

6. The mechanical seal system according to claim 1, comprising: a first temperature detection unit for detecting a first temperature of the flushing fluid before cooling the sliding portion; and a second temperature detection unit for detecting a second temperature of the flushing fluid after cooling the sliding portion, wherein the control unit determines the lubrication state of the sliding portion based on the temperature difference between the first temperature and the second temperature detected by the first temperature detection unit and the second temperature detection unit, only when the determination result of the operating state determination is positive.

7. The mechanical seal system according to claim 3 or claim 6, wherein the control unit determines the amount of leakage of the flushing fluid from the sliding portion to the external area based on the temperature difference as a determination of the lubrication state.

8. The mechanical seal system according to claim 3 or claim 6, wherein the control unit determines the degree of leakage of the flushing fluid from the sliding portion to the external area based on the temperature difference as a determination of the lubrication state.

9. The mechanical seal system according to claim 3 or claim 6, wherein the control unit determines the trend of the lubrication state based on the temperature difference as a determination of the lubrication state.

10. The mechanical seal system according to claim 3 or claim 6, wherein the control unit determines whether the lubrication state is stable based on the temperature difference as a determination of the lubrication state.

11. The mechanical seal system according to claim 3 or claim 6, wherein the control unit determines the degree of instability of the lubrication state based on the temperature difference as a determination of the lubrication state.

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