JP7288847B2 - Pump diagnostic method and pump diagnostic device - Google Patents

Description

The present invention relates to a pump diagnostic method and a pump diagnostic apparatus.

In recent years, pump gates have been installed in addition to or in place of existing sluice gates at the boundaries between upstream and downstream waterways in waterways with a relatively small amount of water, such as tributaries that join the main river. increasing number of cases. The pump gate has a structure in which a submersible pump for draining water from an upstream side water channel to a downstream side water channel is provided on a door body installed in a water channel so that it can be opened and closed. Since the pump gate can be installed directly in the existing waterway, there is no need for a bypass waterway or pumping station space, which is required for conventional drainage pumping stations. It is superior in that it can be reduced to a large extent.

The pump gate is closed when the water level in the downstream waterway becomes high, such as during torrential rain, to prevent backflow from the downstream waterway to the upstream waterway. At this time, the submersible pump is operated to forcibly drain the water in the upstream waterway to the downstream waterway. Conversely, when the water level on the downstream side becomes low as in fine weather, there is no risk of backflow as described above, so the gate body is opened and the inner water in the upstream side waterway naturally flows down to the downstream side waterway.

Due to the nature described above, the operation of the pump gate is limited to emergencies such as torrential rain, but reliability is required for its operation. In other words, there is a need to reliably prevent failures even though there is little opportunity to detect failures or their signs based on normal operating conditions. Therefore, it is preferable that periodic maintenance operation (diagnosis) is performed on the installed pump gate. As such a managed operation method, for pump gate pumps, known managed operation methods related to rotating equipment (for example, Japanese Patent Application Laid-Open No. 2019-21305 (Patent Document 1), Japanese Patent No. 3053305 (Patent Document 2) etc.) may be applied.

JP 2019-21305 A Japanese Patent No. 3053305

By the way, since the pump of the pump gate is originally a device that is driven in water, it is desirable to place the pump in the water during maintenance operation to perform maintenance operation. However, in order to place the pump in the water, it is necessary to close the gate and secure the water level in the upstream waterway. Even short-term closures can be difficult to implement. Moreover, when the water flow rate is low, even if the door body is closed, there may be cases where a sufficient water rate cannot be secured for arranging the pump in the water. Therefore, there is a demand for a technology that enables effective controlled operation even when the pump is placed above the water surface, that is, in a state different from the original operating condition of the pump. Techniques such as those in Patent Documents 1 and 2, which are based on the assumption that the

Therefore, it is desired to realize a pump diagnostic method and a pump diagnostic apparatus that can perform effective diagnosis even under a load environment that is significantly different from the load environment during actual use.

A method for diagnosing a pump according to the present invention is a method for diagnosing a pump having a mechanical seal in a shaft seal portion, wherein the temperature of lubricating oil flowing through the mechanical seal is measured after the operation of the pump is stopped. and an oil amount estimation step of estimating the filling amount of the lubricating oil based on the change tendency of the temperature measured in the stop temperature measurement process.

Further, a pump diagnostic device according to the present invention is a pump diagnostic device capable of diagnosing a pump having a mechanical seal in a shaft seal portion, the temperature measuring portion being capable of measuring the temperature of lubricating oil flowing through the mechanical seal; a diagnostic unit capable of diagnosing the state of the pump based on the change tendency of the temperature measured by the temperature measuring unit; Estimate the filling amount of the lubricating oil based on the temperature change function measured by the stop temperature measurement function that measures the temperature of the flowing lubricating oil using the temperature measurement unit, and the temperature change tendency measured by the stop temperature measurement function. and an oil amount estimation function .

According to these configurations, effective diagnosis can be performed even under a load environment that is significantly different from the load environment during actual use. In particular, when the present invention is implemented in a manner that allows estimation of the filling amount of lubricating oil, the amount of oil can be estimated without installing an oil level gauge, which is difficult to retrofit to the pump. In addition, when estimating the filling amount of lubricating oil in the present invention, the estimation is performed based on the temperature of the lubricating oil. Thus, the measurement of a single key item allows diagnosis of two key items.

Preferred embodiments of the present invention are described below. However, the scope of the present invention is not limited by the preferred embodiments described below.

As one aspect of the pump diagnostic method according to the present invention, after the pump is started from a stopped state, the temperature of the lubricating oil is measured during operation, and the temperature is measured in the temperature measurement during operation. and a calorific value estimating step of estimating the calorific value of the pump based on the obtained temperature change tendency.

According to this configuration, it is possible to more precisely determine whether or not there is an abnormality in the pump or a sign thereof based on a plurality of control items related to lubricating oil.

As one aspect of the pump diagnostic method according to the present invention, in the calorific value estimating step, the estimated calorific value is corrected based on the filling amount estimated in the oil amount estimating step. is preferred.

According to this configuration, the calorific value can be estimated more precisely.

As one aspect of the pump diagnosing method according to the present invention, in the calorific value estimation step, when the estimated calorific value falls below a predetermined threshold value, the filling amount of the lubricating oil is insufficient. It is preferable to determine that

According to this configuration, it is easy to detect the lack of lubricating oil before serious trouble occurs in the pump due to the lack of lubricating oil .

As one aspect, the pump diagnosis method according to the present invention further includes an ambient temperature measuring step of measuring an ambient temperature of the pump, and in the oil amount estimating step, the change corrected based on the ambient temperature It is preferable to estimate the filling amount of the lubricating oil based on the trend .

According to this configuration, it is possible to suppress the influence of disturbance caused by the ambient temperature when determining whether or not there is an abnormality in the pump or a symptom thereof .

Further features and advantages of the invention will become clearer from the following description of exemplary and non-limiting embodiments described with reference to the drawings.

Schematic diagram of the open state of the pump gate according to the present embodiment Schematic diagram of the closed state of the pump gate according to the present embodiment Flow chart of the pump diagnostic method according to the present embodiment The figure showing the installation state of the thermometer which concerns on this embodiment. An example of temporal changes in temperature values measured in the pump diagnostic method according to the present embodiment

An embodiment of a pump diagnostic method and a pump diagnostic device according to the present invention will be described with reference to the drawings. An example in which the pump diagnosis method according to the present invention is applied to diagnosis of a submersible pump 3 of a pump gate 1 installed in a running water channel 100 (an example of a flow channel) will be described below.

[Overview of pump gate]
First, the outline of the pump gate 1 installed with the submersible pump 3 to be diagnosed in the pump diagnostic method according to the present embodiment will be described. The pump gate 1 includes a door 2, a submersible pump 3 provided on the door, and a driving device 4 capable of moving the door 2 up and down (Fig. 1). The pump gate 1 is installed in a flowing water channel 100 at a point where a main stream and a branch stream of a river converge. The water channel 100 has a tributary side water channel 101 and a main stream side water channel 102 .

Normally, as shown in FIG. 1, the gate 2 is arranged above the water surface 103 (example of liquid surface) of water (example of fluid) flowing through the water channel 100, and the operation of the submersible pump 3 is stopped. ing. Water naturally flows down from the tributary side running water channel 101 toward the main stream side running water channel 102 .

When the water level rises due to torrential rain or the like, the water level in the mainstream side flowing water channel 102 may rise. In such a case, in order to prevent water from flowing back from the main flow channel 102 toward the branch flow channel 101, the gate 2 is lowered to block the flow channel 100 (FIG. 2). At this time, the submersible pump 3 is arranged below the water surface 103 . Here, when the submersible pump 3 is operated, water is urged from the tributary side water channel 101 to the main stream side water channel 102, and can be forcibly discharged.

The submersible pump 3 is a known submersible pump, and has a motor, a drive shaft X rotationally driven by the motor, and an impeller attached to the drive shaft X. When the motor is driven, the impeller rotates, and the rotation of the impeller urges water from the tributary side water channel 101 side to the main stream side water channel 102 side. Here, the shaft seal portion of the drive shaft X is sealed with a known mechanical seal 7 . The mechanical seal 7 has a fixed ring 71 fixed to the casing C of the submersible pump 3 and a rotary ring 72 fixed to the drive shaft X. A seal portion 73a is provided between the fixed ring 71 and the rotary ring 72. , 73b are formed. The seal portions 73a and 73b are lubricated with lubricating oil filled in the lubricating oil chamber 5, which is the internal space of the casing C (FIG. 4).

[Pump gate diagnosis]
Due to the nature of the pump gate 1, the submersible pump 3 is not operated in normal times, and is operated only in cases such as torrential rain. On the other hand, when the operation of the submersible pump 3 is required, it is required to operate the submersible pump 3 reliably because it is a case of emergency drainage. In other words, there is a need to reliably prevent failures even though there is little opportunity to detect failures or signs thereof based on normal operating conditions. In view of such requirements, periodic diagnostics are performed on the submersible pump 3 to check for failures and their symptoms. The pump diagnosis method according to the present embodiment includes an operation temperature measurement step S10, a stop temperature measurement step S20, and an estimation step S30. Here, the estimation process has an oil amount estimation process S31 and a calorific value estimation process S32 (Fig. 3). Below, the content of each process is demonstrated.

Before diagnosis, a thermometer 6 (an example of a temperature measuring section) is installed in the lubricating oil chamber 5 of the submersible pump 3 . More specifically, the probe of the thermometer 6 implemented as a thermocouple is installed in the lubricating oil chamber 5 so that its tip 61 is positioned below the liquid level L1 of the lubricating oil (FIG. 4). A detailed position of the tip 61 will be described later. Further, the temperature value measured by the thermometer 6 is input to a computer (not shown) (example of a diagnostic unit, an oil amount estimating unit, and a calorific value estimating unit) connectable to the thermometer 6, and Temperature values can be used in the analytical process. As the thermometer 6 and the computer, known ones can be used.

The operating temperature measurement step S10 is a step performed as the first step of the pump diagnosis method according to the present embodiment, and is a step of measuring the temperature of the lubricating oil while the submersible pump 3 is in operation. The submersible pump 3 is in a completely stopped state at the time when the operating temperature measurement step S10 is started, and the submersible pump 3 is started from a completely stopped state. Note that the operating temperature measurement step S10 is the normal state of the pump gate 1, that is, the gate body 2 is arranged above the water surface 103 of the water flowing through the water channel 100, so that the submersible pump 3 is placed above the water surface 103. It is carried out in the state (Fig. 1) placed in the

Since the submersible pump 3 is started from a completely stopped state as described above, the temperature of the lubricating oil at the time when the submersible pump 3 is started is equivalent to the air temperature (an example of ambient temperature). When the submersible pump 3 is operated, frictional heat is generated in the mechanical seal, so the temperature of the lubricating oil gradually rises. FIG. 5 shows changes over time in the temperature of the lubricating oil, and the section P1 in FIG. 5 corresponds to the operating temperature measurement step S10. More specifically, the submersible pump 3 is started at the start point P1a of the section P1, and stopped at the end point P1b of the section P1.

The subsequent temperature measurement step S20 at the time of operation is a step that starts when the submersible pump 3 is stopped at the end of the temperature measurement step S10 at the time of operation, and measures the temperature of the lubricating oil after the operation of the submersible pump 3 is stopped. It is a process. In the stop temperature measurement step S20, since the operation of the submersible pump 3 is stopped, frictional heat that raises the temperature of the lubricating oil is not generated. On the other hand, since the temperature of the lubricating oil has risen to a temperature higher than the air temperature in the operating temperature measurement step S10, the temperature of the lubricating oil gradually decreases due to heat radiation. In FIG. 5, a section P2 starting from the end point P1b of the operating temperature measurement step S10 (section P1) corresponds to the stop temperature measurement step S20. If the operation of the submersible pump 3 continues to be stopped, the stop temperature measurement step S20 ends after a predetermined period of time has elapsed.

The estimation step S30 estimates the filling amount of lubricating oil and the amount of heat generated in the submersible pump 3 based on the temperature values collected in the operating temperature measurement step S10 and the stop temperature measurement step S20. These estimated information can be the material for determining whether or not the submersible pump 3 can be operated normally. Below, the oil amount estimation step S31 and the calorific value estimation step S32 included in the estimation step S30 will be described in order.

The oil amount estimation step S31 is a step of estimating the amount of lubricating oil filled in the lubricating oil chamber 5 . If the filling amount of the lubricating oil is less than the predetermined lower limit, the mechanical seal cannot be lubricated, and there is a possibility that problems such as breakage of the mechanical seal may occur. Therefore, the filling amount of lubricating oil is an important control item for the submersible pump 3 . In the following description, a state in which the amount of lubricating oil filled is within a predetermined reference value range is referred to as a "reference state."

In the oil amount estimating step S31, a temperature change ΔT _off per unit time (example of temperature change tendency) is calculated based on the temperature values collected in the stop temperature measuring step S20. In FIG. 5, the slope of the temperature in section P2 represents _ΔToff . Here, ΔT _off becomes a negative value because the temperature of the lubricating oil gradually decreases in the stop temperature measurement step S20.

When the filling amount of lubricating oil falls below a predetermined lower limit, the liquid level of lubricating oil becomes low (chain double-dashed line L2 in FIG. 5). At this time, the tip 61 is exposed above the liquid surface, and the thermometer 6 detects the temperature of the air instead of the temperature of the lubricating oil. Here, the frictional heat in the mechanical seal raises the temperature of the lubricating oil, but the heat is hardly transferred to the air, so the temperature rise width accompanying the operation of the submersible pump 3 becomes small (two points in FIG. 5 dashed line). Therefore, the absolute value of ΔT _off becomes smaller than the reference value. Therefore, when the ΔT _off calculated in the stop temperature measurement step S20 is larger than the predetermined reference value (the absolute value is small), it can be determined that the amount of lubricating oil charged is below the predetermined lower limit. The above reference value is set based on the temperature change per unit time when the amount of lubricating oil filled is at the predetermined lower limit.

Further, the larger the amount of lubricating oil filled, the larger the heat capacity of the entire lubricating oil, so the absolute value of ΔT _off becomes smaller. For example, comparing the solid line and the one-dot chain line in FIG. 5, the one-dot chain line has a larger absolute value of _ΔToff . Therefore, the dashed-dotted line in FIG. 5 represents a state in which the amount of lubricating oil filled is smaller than that of the solid line. Thus, if the relationship between the filling amount of lubricating oil and ΔT _off is clarified in advance, the filling amount V of lubricating oil can be estimated based on the calculated value of ΔT _off .

The calorific value estimation step S<b>32 is a step of estimating the calorific value of the submersible pump 3 . In the submersible pump 3, the amount of heat generated changes as the sliding state of the mechanical seal changes. For example, if the sliding condition is poor, the amount of heat generated increases. On the other hand, if the sliding condition is good, the amount of heat generated will be small. suspected to be Therefore, if the amount of heat generated can be estimated, it will be an important clue to detect mechanical seal failure or its symptoms.

In the calorific value estimation step S32, a temperature change ΔT _on per unit time (an example of temperature change tendency) is calculated based on the temperature values collected in the operating temperature measurement step S10. In FIG. 5, the slope of the temperature in section P1 represents ΔT _on . Here, since the temperature of the lubricating oil gradually rises in the operating temperature measurement step S10, ΔT _on becomes a positive value. Here, when the calculated ΔT _on is larger than a predetermined reference value, there is a possibility that the amount of heat generated is larger than when the mechanical seal is in a normal state. Conversely, if the calculated ΔT _on is smaller than the predetermined reference value, there is a possibility that the amount of leakage has increased in the sliding portion. Thus, the calculated value of ΔT _on indicates the likelihood that a fault or symptom thereof exists. The above reference value is set based on the temperature change per unit time in a state where the submersible pump 3 is guaranteed to be normal (such as after a final inspection at the time of manufacture).

Also, ΔT _on , which is the temperature change per unit time of the lubricating oil, is affected by parameters such as the heat capacity and heat dissipation of the lubricating oil as a whole, in addition to the amount of heat generated. Here, if it is assumed that parameters other than the calorific value are constant, the calorific value Q can be calculated based on ΔT _on (equation (1)).
Q=C・d・V ₀・ΔT _on +H formula (1)
However, in equation (1), C is the specific heat of the lubricating oil, d is the density of the lubricating oil, _V0 is the volume of the lubricating oil, and H is the heat release amount. where C and d are constants based on the substance of the lubricating oil, and V ₀ and H are constants based on the structure of the submersible pump 3 and the standard value of the lubricating oil filling amount.

Furthermore, in the equation (1), the volume of the lubricating oil is assumed to be a constant value V ₀ , but if this is replaced with the filling amount V of the lubricating oil calculated in the oil amount estimation step S31, the calorific value can be estimated more accurately. become. The corrected calorific value _Qc is represented by the following equation (2).
_Qc =(Q−H)·V/ _V0 +H Formula (2)

Through the above procedure, the filling amount V of the lubricating oil and the calorific value Q _c (or Q) in the submersible pump 3 can be estimated. A manager of the pump gate 1 can detect failure or signs of failure of the submersible pump 3 based on the estimated filling amount V and calorific value _Qc , and perform maintenance of the submersible pump 3 .

[Modification of above embodiment]
In addition to the operating temperature measurement step S10, stop temperature measurement step S20, and estimation step S30 described in the above embodiment, an ambient temperature measurement step may be provided. The ambient temperature measurement step is a step of measuring the ambient temperature of the location where the submersible pump 3 is installed using a known thermometer. Here, air temperature, water temperature, and the like are exemplified as the ambient temperature, but in this modified example, an embodiment using air temperature as the ambient temperature will be described. The ambient temperature measurement step can be performed at any time within a period in which the temperature can be the same as when the temperature measurement step S10 during operation and the temperature measurement step S20 are performed. It can be executed immediately before, between the operating temperature measurement step S10 and the stop temperature measurement step S20, and immediately after the stop temperature measurement step S20. At this time, the surrounding temperature may be measured before installing the thermometer 6 in the lubricating oil chamber 5 so that the temperature can be measured using the thermometer 6 . The measured temperature values are entered into a computer.

In general, the amount of heat released from an object in the air is proportional to the temperature difference between the object and the air temperature. Therefore, ΔT _off can be affected by temperature. That is, when the air temperature is low, the amount of heat radiated from the submersible pump 3 to the air increases, so _ΔToff decreases. Conversely, when the air temperature is high, ΔT _off increases. If the method for diagnosing a pump according to the present embodiment includes an air temperature measurement step, ΔT _off can be corrected based on the measured air temperature.

It should be noted that it is not necessary to directly measure the temperature of the air when measuring the air temperature in the above modified example. For example, when a sufficient amount of time has passed since the submersible pump 3 was last operated, the lubricating oil temperature can be equated with the air temperature. Therefore, the lubricating oil temperature measured before the start of the operating temperature measurement step S10 may be used as the ambient temperature.

[Other embodiments]
Finally, another embodiment of the pump diagnostic method according to the present invention will be described. It should be noted that the configurations disclosed in the respective embodiments below can also be applied in combination with configurations disclosed in other embodiments unless there is a contradiction.

In the above-described embodiment, the configuration in which the diagnosis method according to the present invention is applied to the diagnosis of the pump gate 1 (submersible pump 3) has been described as an example. However, the method for diagnosing a pump according to the present invention can also be applied to diagnosing a pump such as a drainage station pump, a manhole pump, or a land pump.

In the above embodiment, an example of the pump diagnosis method including the operating temperature measurement step S10 and the stop temperature measurement step S20 has been described. However, the method for diagnosing a pump according to the present invention does not have to include one of the operating temperature measurement step and the stop temperature measurement step.

In the above-described embodiment, an example of the pump diagnosis method including the temperature measurement step S10 during operation and the temperature measurement step S20 during stop has been described. However, the method for diagnosing a pump according to the present invention may include the step of temperature measurement during operation and the step of temperature measurement during stop multiple times. Further, the number of times of the temperature measurement process during operation and the temperature measurement process during stop may be different.

In the above-described embodiment, the temperature measurement step S10 during operation and the temperature measurement step S20 during stop are performed with the submersible pump 3 placed above the water surface 103 . However, in the method for diagnosing a pump according to the present invention, the step of temperature measurement during operation and the step of temperature measurement during stop may be performed while the pump is placed in water. In this case, if an ambient temperature measuring step is provided, it is preferable to measure the water temperature as the ambient temperature.

In the above-described embodiment, in the calorific value estimating step S32, the calorific value Q is corrected based on the filling amount V of the lubricating oil estimated in the oil amount estimating step S31. However, if the pump diagnosis method according to the present invention includes the calorific value estimation step, the calorific value based on the estimated filling amount of lubricating oil need not be corrected.

In the method for diagnosing a pump according to the present invention, the device for measuring temperature may be installed each time diagnosis is performed, or may be permanently installed.

The method for diagnosing a pump according to the present invention may be configured to determine in the calorific value estimation step that the amount of lubricating oil charged is insufficient when the estimated calorific value falls below a predetermined threshold. good. Further, in this case, when it is determined that the amount of lubricating oil filled is insufficient, an alarm may be issued separately from the diagnosis result.

In the case where the method for diagnosing a pump according to the present invention includes the step of temperature measurement during operation, when the temperature measured in the step of temperature measurement during operation exceeds a predetermined upper limit value, an alarm is issued separately from the diagnosis result. You may do so.

In the method for diagnosing a pump according to the present invention, information about the temperature and its change over time collected in the temperature measurement step during operation and the temperature measurement step when stopped, information about the filling amount of lubricating oil estimated in the oil amount estimation step, and Information about the calorific value of the lubricating oil estimated in the calorific value estimation step may be accumulated in a known server device. With this configuration, it is possible to remotely confirm various information related to diagnosis accumulated in the server device.

Regarding other configurations, it should be understood that the embodiments disclosed in this specification are examples in all respects, and that the scope of the present invention is not limited by them. Those skilled in the art will easily understand that modifications can be made as appropriate without departing from the scope of the present invention. Therefore, other embodiments modified without departing from the gist of the present invention are naturally included in the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be used, for example, as a method for diagnosing a submersible pump of a pump gate installed in a running water channel.

1: Pump gate 2: Gate body 3: Submersible pump 4: Driving device 5: Lubricating oil chamber 6: Thermometer 61: Thermometer probe tip 7: Mechanical seal 71: Fixed ring L1: Lubricating oil level (reference situation)
L2: Liquid level of lubricating oil (when filling amount decreases)
X: drive shaft 100: water channel 101: tributary side water channel 102: main stream side water channel 103: water surface P1: section (operation temperature measurement step S10)
P1a: starting point (operational temperature measurement step S10)
P1b: end point (operational temperature measurement step S10)
P2: section (stop temperature measurement step S20)
ΔT _on : temperature change (operational temperature measurement step S10)
ΔT _off : temperature change (stop temperature measurement step S20)

Claims (6)

A diagnostic method for a pump having a mechanical seal in a shaft seal, comprising:
A stopping temperature measuring step of measuring the temperature of the lubricating oil flowing through the mechanical seal after the operation of the pump is stopped;
an oil amount estimation step of estimating the filling amount of the lubricating oil based on the temperature change tendency measured in the stop temperature measurement step. an operating temperature measuring step of measuring the temperature of the lubricating oil after starting the pump from a stopped state;
2. The pump diagnostic method according to claim 1, further comprising a calorific value estimation step of estimating a calorific value of the pump based on the temperature change tendency measured in the operating temperature measurement step. 3. The method of diagnosing a pump according to claim 2, wherein in the calorific value estimation step, the estimated calorific value is corrected based on the filling amount estimated in the oil amount estimating step. 4. The method of diagnosing a pump according to claim 2, wherein in the calorific value estimating step, it is determined that the filling amount of the lubricating oil is insufficient when the estimated calorific value falls below a predetermined threshold value. further comprising an ambient temperature measuring step of measuring the ambient temperature of the pump;
The pump diagnosis method according to any one of claims 1 to 4 , wherein in the oil amount estimation step, the filling amount of the lubricating oil is estimated based on the change tendency corrected based on the ambient temperature. A pump diagnostic device capable of diagnosing a pump having a mechanical seal in a shaft seal,
A temperature measuring unit capable of measuring the temperature of lubricating oil flowing through the mechanical seal, and a diagnostic unit capable of diagnosing the state of the pump based on the temperature change tendency measured by the temperature measuring unit,
The diagnosis unit
A stopping temperature measuring function for measuring the temperature of lubricating oil flowing through the mechanical seal after the operation of the pump is stopped using the temperature measuring unit;
and an oil amount estimating function for estimating the filling amount of the lubricating oil based on the temperature change tendency measured by the stop temperature measuring function.

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