JP7690937B2 - Oil chamber monitoring device, submersible pump, and oil chamber monitoring method - Google Patents

Description

The present invention relates to an oil chamber monitoring device, a submersible pump, and an oil chamber monitoring method.

Conventionally, submersible pumps are used for a variety of purposes, including sewage and drainage. Submersible pumps use a motor to rotate a main shaft to suck up water and drain it, but a mechanical seal (shaft seal device) is attached to the main shaft to prevent water from entering the motor. In addition, an oil chamber filled with oil is provided near the main shaft, and the oil is supplied to the mechanical seal to lubricate its sliding surface, contributing to the quality and reliability of the submersible pump.

Generally, if an oil leak occurs, it can lead to a malfunction of the submersible pump, so it is important to monitor the amount of oil sealed in the oil chamber. For example, Patent Document 1 discloses technology relating to a pump diagnostic method that detects pump failure or signs of failure by measuring the temperature of the lubricating oil flowing through the mechanical seal after the pump operation is stopped and estimating the amount of lubricating oil filled based on the trend of change in the measured temperature.

JP 2021-102925 A

However, the pump diagnostic method described in Patent Document 1 only estimates the amount of lubricating oil filled after the pump operation is stopped, and has the problem that it cannot properly monitor the condition of the oil chamber, including oil leakage and flooding in the oil chamber.

The present invention has been made in consideration of the above problems, and one of the objects of the present invention is to provide an oil chamber monitoring device, an underwater pump, and an oil chamber monitoring method that can properly monitor the inside of the oil chamber.

The oil chamber monitoring device according to one aspect of the present invention is an oil chamber monitoring device that monitors an oil chamber in which oil is sealed to be supplied to a mechanical seal of an underwater pump, and includes a pressure sensor that detects the pressure in the oil chamber, a space temperature sensor that detects the space temperature in the oil chamber, an oil temperature sensor that detects the oil temperature in the oil chamber, and a calculation means that calculates the amount of oil leakage or water ingress from the oil chamber from the displacement of the space volume and oil volume of the oil chamber between the first and second points in time based on the first pressure, which is the pressure, the first space temperature, which is the space temperature, and the first oil temperature, which is the oil temperature, at the first point in time, and the second pressure, which is the pressure, the second space temperature, which is the space temperature, and the second oil temperature, which is the oil temperature, at the second point in time.

In the above aspect, the calculation means may calculate the spatial volume of the oil chamber at a second point in time relative to the first point in time using the first pressure and first space temperature, and the second pressure and second space temperature, and may calculate the oil volume of the oil chamber at the second point in time relative to the first point in time using the first oil temperature and the second oil temperature.

In the above aspect, the calculation means may calculate the amount of oil leakage or water ingress from the oil chamber based on the spatial volume of the oil chamber at a second point in time relative to the first point in time, the oil volume of the oil chamber at a second point in time relative to the first point in time, and the volume of the oil chamber.

In the above embodiment, the spatial volume of the oil chamber may be calculated using Boyle's law.

In the above embodiment, the oil volume of the oil chamber may be calculated based on the oil expansion coefficient of the oil.

In the above aspect, the first point in time may be when the submersible pump is stopped, and the second point in time may be when the submersible pump is operating.

In the above aspect, the device may further include an actual oil volume calculation means for calculating the amount of oil actually sealed in the oil chamber based on the pressure detected by the pressure sensor, assuming that a preset amount of oil is sealed in the oil chamber.

In the above embodiment, the actual amount of oil filled may be calculated according to a predetermined temperature change.

In the above embodiment, the actual amount of oil filled may be calculated while the submersible pump is stopped.

The submersible pump according to one aspect of the present invention comprises the oil chamber monitoring device, a motor, a rotating shaft that rotates when the motor is driven, and an impeller that rotates in the pump chamber as the rotating shaft rotates, drawing in liquid from the suction port and generating a flow toward the discharge port.

An oil chamber monitoring method according to one aspect of the present invention is an oil chamber monitoring method executed by an oil chamber monitoring device that monitors an oil chamber filled with oil to be supplied to a mechanical seal of an underwater pump, and includes acquiring the pressure of the oil chamber detected by a pressure sensor, acquiring the space temperature of the oil chamber detected by a space temperature sensor, acquiring the oil temperature of the oil chamber detected by an oil temperature sensor, and calculating the amount of oil leakage or water ingress from the oil chamber from the displacement of the space volume and oil volume of the oil chamber between the first and second points in time based on the first pressure, which is the pressure, the first space temperature, which is the space temperature, and the first oil temperature, which is the oil temperature, at a first point in time, and the second pressure, which is the pressure, the second space temperature, which is the space temperature, and the second oil temperature, which is the oil temperature, at a second point in time.

The present invention provides an oil chamber monitoring device, a submersible pump, and an oil chamber monitoring method that can properly monitor the inside of the oil chamber.

1 is a structural diagram showing an overview of a submersible pump 10 according to a first embodiment of the present invention. FIG. 4 is a diagram showing a schematic view of an oil chamber. FIG. 13 is a schematic diagram showing the state of an oil chamber to explain monitoring of oil leakage and water ingress in the oil chamber. 1 is a flowchart showing the processing flow of an oil chamber monitoring method M100 executed by an oil chamber monitoring device included in the submersible pump 10 according to the first embodiment of the present invention. 10 is a diagram showing a schematic view of an oil chamber for explaining calculation of an actual amount of oil sealed in the oil chamber; FIG. 1 is a graph showing the change in pressure in the oil chamber detected by pressure sensor 110 when the actual amount of oil sealed in the oil chamber is the same as that in the oil chamber when it is assumed that a predetermined amount of oil is sealed in the oil chamber.

Below, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Note that each embodiment described below is merely a specific example for implementing the present invention, and is not intended to limit the interpretation of the present invention. In addition, to facilitate understanding of the description, the same components in each drawing will be given the same reference numerals as much as possible, and duplicate descriptions may be omitted.

First Embodiment
[About the structure of submersible pumps]
Fig. 1 is a structural diagram showing an overview of a submersible pump 10 according to a first embodiment of the present invention. As shown in Fig. 1, the submersible pump 10 has a motor 11, a rotating shaft 12, an oil chamber 13, a mechanical seal (shaft sealing device) 14, a pump chamber 15, and an impeller 16, and also includes other components such as bearings and an oil lifter, but a detailed description of the configuration will be omitted here.

The motor 11 is configured to drive the impeller 16 connected to the tip of the rotating shaft 12 via the rotating shaft 12. For example, the motor 11 has a stator (coil) and a rotor, and rotates the rotor by a magnetic field generated in the stator.

The rotating shaft 12 is arranged to extend from the motor 11 through the oil chamber 13 to the pump chamber 15, and an impeller 16 is arranged at its tip. When the motor 11 is driven, the rotating shaft 12 is configured to transmit the driving force (torque) of the motor 11 to the impeller 16.

The oil chamber 13 is disposed between the motor 11 and the pump chamber 15, and oil is sealed in the oil chamber 13. A mechanical seal 14 is disposed in the oil chamber 13, and the mechanical seal 14 is attached in an annular shape so as to surround the outer periphery of the rotating shaft 12 that passes through the oil chamber 13.

The mechanical seal 14 has an oil film forming portion on the sliding surface, which prevents water from entering the oil chamber 13 from the pump chamber 15 and prevents oil from the oil chamber 13 from flowing into the motor 11 (motor chamber). In addition, the sliding surface is lubricated by the oil filled in the oil chamber 13 and is cooled to prevent burning.

An impeller 16 is disposed in the pump chamber 15, and the impeller 16 connected to the tip of the motor 11 via the rotating shaft 12 is rotated by the motor 11. As the impeller 16 rotates, liquid flows into the pump chamber 15 from the suction port and flows out of the discharge port.

The impeller 16 is attached to the tip of the rotating shaft 12 and is disposed in the pump chamber 15. As described above, the impeller 16 is driven to rotate via the rotating shaft 12 by the motor 11, and is configured to draw in liquid from the suction port and generate a flow toward the discharge port, causing the liquid to flow out from the discharge port.

Furthermore, the submersible pump 10 is provided with a pressure sensor 110, a space temperature sensor 120, and an oil temperature sensor 130 as an oil chamber monitoring device for monitoring the oil chamber 13, and is configured with a control unit (calculation means) for processing the data detected by these sensors.

[Oil chamber monitoring device]
Next, the configuration and function of the oil chamber monitoring device will be described.
Fig. 2 is a schematic diagram showing the state of the oil chamber, which shows two states, for example, (A) when the submersible pump 10 is stopped (stopped state) and (B) when the submersible pump 10 is operating (operating state).

At these two points in time (states), the pressure sensor 110 detects the pressure in the oil chamber, the space temperature sensor 120 detects the space temperature in the oil chamber, and the oil temperature sensor 130 detects the oil temperature in the oil chamber. Then, based on the data detected by each, for example, a control unit (calculation means) in the oil chamber monitoring device calculates the amount of oil leakage or water ingress in the oil chamber from the displacement of the space volume and oil volume in the oil chamber when the engine is stopped and when the engine is operating. The calculation process is described in detail below.

(A) When stopped (first time point), there is a first pressure P which is the pressure in the oil chamber, a first space temperature _T1 which is the space temperature in the oil chamber, and a first oil temperature T2 which is the oil temperature in the oil _chamber , and further there are an oil chamber volume V, a first space volume _V1 , and a first oil volume _V2 .

(B) During operation (second point in time), there is a second pressure P' which is the pressure in the oil chamber, a second space temperature _T1 ' which is the space temperature in the oil chamber, and a second oil temperature T2' which is the oil temperature in the oil _chamber , and further there are an oil chamber volume V, a second space volume _V1 ', and a second oil volume _V2 '.

For example, by operating the submersible pump 10, the temperature of the oil chamber may rise and the oil sealed in the oil chamber may expand, but (A) when stopped and (B) when operating, the oil chamber volume V is constant and satisfies the following (Equation 1) and (Equation 2). Generally, the amount of oil sealed in the oil chamber is specified as, for example, 80% of the oil chamber volume V at a specified oil temperature, and it is advisable to seal the oil in accordance with this specification.

Here, when Boyle's law is used for two points in time (states), the following (Equation 3) is satisfied.

The second oil volume _V2 ' can be calculated using the oil expansion coefficient α. The oil expansion coefficient α is determined in advance according to the type of oil filled in the oil chamber. For example, the oil volume changes in response to temperature changes, such as the oil volume expanding in response to an increase in temperature. Therefore, the oil expansion coefficient α is expressed as shown below (Equation 4) using the first oil temperature _T2 when the engine is stopped and the second oil temperature _T2 ' when the engine is operating.

If the temperature of the oil chamber rises and the oil sealed in the oil chamber expands when the underwater pump 10 is stopped and then started, the second oil volume _V2 ' when the pump is running relative to when it is stopped can be expressed as follows (Equation 5) using the oil expansion coefficient α and the first oil volume _V2 .

By substituting the second spatial volume V ₁ ' (Equation 3 above) and the second oil volume V ₂ ' (Equation 5 above) into Equation 2 above, the oil chamber volume V can be expressed as in Equation 6 below.

The oil chamber volume V satisfies the above relationship (Equation 6) using the first pressure P, first space temperature T1, first oil temperature _T2 , and the second pressure P', second space temperature T1', and second oil temperature T2' detected by the pressure sensor ₁₁₀ , space temperature sensor ₁₂₀ , and oil temperature sensor ₁₃₀ when the underwater pump 10 is stopped and operating.

[Oil leakage and water ingress from the oil chamber]
Fig. 3 is a schematic diagram of the oil chamber to explain monitoring of oil leakage and flooding in the oil chamber. In Fig. 3, similar to Fig. 2, the oil chamber is shown in two states, for example, (A) when the submersible pump 10 is stopped (stopped state) and (B) when the submersible pump 10 is operating (operating state).

Here, (B) assuming that water ingress (water ingress amount V _W ) into the oil chamber occurs during operation, the oil chamber volume V satisfies the relationship of the following (Equation 7).

When the above (Equation 7) is solved for the flooded water amount _VW , the following (Equation 8) can be obtained.

Here, with regard to the second spatial volume _V1 ' and the second oil volume _V2 ', similarly to what was explained using FIG. 2, by substituting the above (Equation 3) and (Equation 5) using Boyle's law and the oil expansion coefficient α, the flooded water volume _VW can be expressed as shown in the following (Equation 9).

Since the oil chamber volume V is preset and constant, as shown in the above (Equation 9), the flooding volume _VW can be calculated using the first pressure P, first space temperature T1, first oil temperature T2, and the second pressure P', second space temperature T1 _' , and second oil temperature _T2 ' detected by the pressure sensor 110, space temperature sensor ₁₂₀ , and oil temperature sensor ₁₃₀ when the underwater pump 10 is stopped and operating.

When the amount of water ingress _VW is greater than 0 (the amount of water ingress _VW is positive), this indicates that water has ingressed into the oil chamber, and when the amount of water ingress _VW is less than 0 (the amount of water ingress _VW is negative), this indicates that oil is leaking from the oil chamber.

[Oil chamber monitoring method]
Next, the oil chamber monitoring method executed by the oil chamber monitoring device that monitors the oil chamber of the submersible pump 10 will be described in detail.

Figure 4 is a flowchart showing the process flow of the oil chamber monitoring method M100 executed by the oil chamber monitoring device included in the submersible pump 10 according to the first embodiment of the present invention. As shown in Figure 4, the oil chamber monitoring method M100 includes steps S110 to S140, and each step is executed by a control unit (processor) included in the oil chamber monitoring device.

In step S110, when the submersible pump 10 is stopped (first time point), the pressure sensor 110 detects the pressure in the oil chamber (first pressure), the space temperature sensor 120 detects the space temperature in the oil chamber (first space temperature), and the oil temperature sensor 130 detects the oil temperature in the oil chamber (first oil temperature).

In step S120, when the submersible pump 10 is operating (second time point), the pressure sensor 110 detects the pressure in the oil chamber (second pressure), the space temperature sensor 120 detects the space temperature in the oil chamber (second space temperature), and the oil temperature sensor 130 detects the oil temperature in the oil chamber (second oil temperature).

Here, the time when the submersible pump 10 is operating (second time point) may be the timing when a predetermined temperature change (e.g., a 10°C increase) occurs after the submersible pump 10 starts operating. Here, the predetermined temperature change may be a temperature change in the spatial temperature of the oil chamber, a temperature change in the oil temperature, or a combination of these.

In step S130, the control unit (calculation means) calculates the spatial volume of the oil chamber at the second time point relative to the first time point based on the first pressure and first space temperature detected in step S110 and the second pressure and second space temperature detected in step S120. As a specific example, the control unit calculates the second spatial volume _V1 ' using the above (Equation 3) using Boyle's law.

The control unit (calculation means) also calculates the oil volume of the oil chamber at the second point in time relative to the first point in time based on the first oil temperature detected in step S110 and the second oil temperature detected in step S120. As a specific example, the control unit calculates the second oil volume _V2 ' by the above (Equation 5) using the oil expansion coefficient related to the oil temperature change.

In step S140, the control unit (calculation means) calculates the amount of oil leakage or flooding in the oil chamber based on the spatial volume and oil volume of the oil chamber at the second time point calculated in step S130. As a specific example, the control unit uses the above (Equation 9) to calculate the amount of oil leakage _Vw (if < 0) or the amount of flooding _Vw (if > 0) in the oil chamber from the first time point to the second time point.

As described above, according to the submersible pump 10 of the first embodiment of the present invention, the oil chamber monitoring device detects the pressure in the oil chamber using the pressure sensor 110, detects the space temperature in the oil chamber using the space temperature sensor 120, and detects the oil temperature in the oil chamber using the oil temperature sensor 130 when the submersible pump 10 is stopped and operating. Then, based on the data detected by each, for example, a control unit (calculation means) in the oil chamber monitoring device can calculate the amount of oil leakage or flooding in the oil chamber from the displacement of the space volume and oil volume of the oil chamber when the pump is stopped and operating, and can appropriately monitor the inside of the oil chamber.

In this embodiment, the time when the submersible pump 10 is stopped is set as the first time point, and the time when the submersible pump 10 is operating is set as the second time point, and data is detected by the pressure sensor 110, the space temperature sensor 120, and the oil temperature sensor 130, respectively. However, the timing of detection is not limited to this. For example, the two timings when the submersible pump 10 is stopped may be set as the first and second time points, and oil leakage and flooding in the oil chamber before the operation of the submersible pump 10 may be checked, or the two timings when the submersible pump 10 is operating may be set as the first and second time points, and oil leakage and flooding in the oil chamber at any time point during the operation of the submersible pump 10 may be checked. In addition, by continuously setting the first and second time points, oil leakage and flooding in the oil chamber can be continuously monitored.

Second Embodiment
Next, in a second embodiment of the present invention, a method for calculating the amount of oil actually sealed in the oil chamber will be described. The basic configuration of the submersible pump according to this embodiment is similar to that of the submersible pump 10 described in the first embodiment of the present invention, and the differences from the first embodiment of the present invention will be mainly described here.

Generally, the amount of oil to be sealed in the oil chamber is specified as, for example, about 80% of the oil chamber volume V at a given oil temperature, and is sealed in accordance with this specification, but there may be cases where the appropriate amount of oil is not sealed, or where an error actually occurs even when the appropriate amount of oil is sealed.

The oil chamber monitoring device included in the submersible pump 10 according to the second embodiment of the present invention further includes an actual oil amount calculation means (not shown) for calculating the amount of oil actually sealed in the oil chamber.

The actual oil volume calculation means calculates the actual oil volume based on the pressure in the oil chamber detected by the pressure sensor 110, assuming that a preset amount of oil is sealed in the oil chamber.

[Actual amount of oil included]
5 is a diagram showing the oil chamber in schematic form to explain how to calculate the amount of oil actually sealed in the oil chamber. In FIG. 5, the oil chamber is shown in two states, for example, (A) when the submersible pump 10 is stopped (stopped state) and (B) when the submersible pump 10 is operating (operating state).

(A) When the engine is stopped (first time point), there is a first pressure P which is the pressure in the oil chamber, a first space temperature _T1 which is the space temperature in the oil chamber, a first oil temperature _T2 which is the oil temperature in the oil chamber, and an oil chamber volume V. The amount of oil actually sealed in the oil chamber is a first oil volume X, and the first space volume at that time is _VX .

(B) During operation (second time point), there is a second pressure P _X which is the pressure in the oil chamber, a second space temperature T ₁ ' which is the space temperature in the oil chamber, a second oil temperature T ₂ ' which is the oil temperature in the oil chamber, and further, an oil chamber volume V. Furthermore, there are a second space volume V _X ' and a second oil volume X'.

Figure 6 is a graph showing the change in oil chamber pressure detected by pressure sensor 110 when the actual amount of oil contained in the oil chamber is the same as that when a preset amount of oil is assumed to be contained in the oil chamber.

FIG. 6 shows an actual pressure value 601 detected by the pressure sensor 110 in the case where a first oil volume X is sealed in the oil chamber at a first time point as shown in FIG. 5, and a theoretical pressure value 602 calculated in advance assuming a first oil volume V2 sealed in the oil chamber at a first time point as shown in FIG. ₂ (for example, 80% of the volume V of the oil chamber is set as a default amount).

In addition, the first space temperature _T1 and the first oil temperature _T2 are when the submersible pump 10 is stopped (first point in time), and the time when the submersible pump 10 starts operating and there is a temperature change from the first space temperature _T1 or the first oil temperature _T2 (here, a 10°C increase) is when the submersible pump 10 is operating (second point in time), and the actual measured pressure 601 at this time is the second pressure _Px , and the theoretical pressure 602 is the second pressure P'.

In other words, since there is an error between the amount of oil actually sealed in the oil chamber and the amount of oil that is set to, for example, 80% of the volume V of the oil chamber, a difference occurs between the actual measured pressure detected by the pressure sensor 110 and the theoretical pressure. The pressure difference ΔP between the actual measured pressure (second pressure P _X ) at the second time point and the theoretical pressure (second pressure P') can be expressed as follows (Equation 10).

Furthermore, for the two time points (states) shown in FIG. 2, when Boyle's law is used, the second pressure P′ at the theoretical pressure 602 satisfies the following (Equation 11).

In addition, when Boyle's law is used for the two time points (states) shown in FIG. 5, the second pressure P _x at the actual measured pressure value 601 satisfies the following (Equation 12).

By substituting the second pressure P′ (expressed in equation 11 above) as the theoretical pressure value and the second pressure P _X (expressed in equation 12 above) as the measured pressure value into equation 10 above, the differential pressure ΔP can be expressed as shown in equation 13 below.

Furthermore, for the two time points (states) shown in FIG. 5, solving the above equation (13) for the first spatial volume _Vx /second spatial volume Vx _' as the displacement of the spatial volume of the oil chamber can be expressed as the following equation (14).

In this way, the first spatial volume _VX /second spatial volume _VX ' as the displacement of the spatial volume of the oil chamber can be calculated using the first spatial temperature _T1 and second spatial temperature T1' detected by the spatial temperature sensor ₁₂₀ and the first pressure P detected by the pressure sensor 110 at the two time points (states) shown in Figure 5, and further using the first spatial volume _V1 and second spatial volume _V1 ' calculated in advance, assuming that 80% of the volume V of the oil chamber is filled with oil at the two time points (states) shown in Figure 2.

Then, the actual oil amount calculation means calculates the actual oil amount X that is actually sealed in the oil chamber shown in Figure 5.

First, at the first time point, since the oil sealed in the oil chamber has not yet expanded, the oil chamber volume V satisfies the following (Equation 15).

Next, when the submersible pump 10 starts operating, the temperature of the oil chamber rises and the oil sealed in the oil chamber expands. The oil chamber volume V at the second time point can be expressed as follows (Equation 16) using the second space volume _Vx ' and the second oil volume X'. The second oil volume X' can be expressed using the oil expansion coefficient α.

When the above (Equation 15) is solved for the first spatial volume _VX , the following (Equation 17) can be obtained.

When the above (Equation 16) is solved for the second spatial volume V _X ', the following (Equation 18) can be obtained.

From the above (Equation 17) and (Equation 18), when solving the first spatial volume V _x /second spatial volume V _x ' as the displacement of the spatial volume of the oil chamber, the following (Equation 19) can be obtained.

From the above (Equation 19), the actual amount of oil X actually sealed in the oil chamber can be expressed as the following (Equation 20).

Here, by substituting ( _Vx / _Vx ') shown in (Equation 14) above into (Equation 20) above, the actual amount of oil sealed in, X, can be calculated.

[Amount of oil leakage and water ingress from the oil chamber]
As described above, the procedure for calculating the amount of oil leakage or water ingress from the oil chamber after calculating the actual amount of oil X actually sealed in the oil chamber will be described.

The amount of oil leakage or flooding in the oil chamber is calculated as the flooding amount _VW shown in the above (Equation 9) as explained with reference to Fig. 3. Here, (A) when stopped (first time point), there is a first pressure P which is the pressure in the oil chamber, a first space temperature _T1 which is the space temperature in the oil chamber, and a first oil temperature _T2 which is the oil temperature in the oil chamber, and further there is an oil chamber volume V. Then, the amount of oil actually sealed in the oil chamber is the first oil volume X ( _V2 in the above (Equation 9)), and the first space volume _VX ( _V1 in the above (Equation 9)) at this time can be expressed as the oil chamber volume V - the first oil volume X.

(B) During operation (second time point), there is a second pressure P _X (P' in the above (Equation 9)) which is the pressure in the oil chamber, a second space temperature T ₁ ' which is the space temperature in the oil chamber, a second oil temperature T ₂ ' which is the oil temperature in the oil chamber, and further, an oil chamber volume V. Furthermore, it is assumed that the second space volume V _X ' and the second oil volume X'.

By summarizing these in light of the above (Equation 9), the amount of water entering the oil chamber V _W (oil leakage V _W from the oil chamber) can be expressed as shown below (Equation 21).

Then, the amount of flooded water _VW is calculated by substituting the actual amount of oil X calculated by (Equation 20) above into (Equation 21) above.

As described above, according to the submersible pump 10 of the second embodiment of the present invention, the actual oil amount calculation means calculates the actual oil amount X that is actually sealed in the oil chamber, and then calculates the amount of oil leakage or flooding in the oil chamber, so that the inside of the oil chamber can be monitored more accurately and appropriately.

Although a preset amount of oil is set as the amount of oil to be sealed in the oil chamber, there is a possibility that an error will occur in the actual amount of oil sealed in. Even if such an error occurs, the amount of oil actually sealed in the oil chamber, X, is calculated, and then the amount of oil leakage or water ingress in the oil chamber is calculated, so the inside of the oil chamber can be monitored more accurately and appropriately.

In this embodiment, as described with reference to Figures 5 and 6, the actual amount of oil X is calculated in response to a temperature rise of 10°C, but this is not limited to this, and it may be calculated in response to a predetermined temperature change, for example, a temperature rise or fall of 5°C, 15°C, or 20°C. If a predetermined temperature change occurs, it is possible to calculate the actual amount of oil X, but the larger the temperature change, the more appropriate the calculation result.

In addition, in this embodiment, the time when the submersible pump 10 is stopped is set as the first time point, and the time when the submersible pump 10 is operating is set as the second time point, and a predetermined temperature change (temperature increase of 10°C) occurs to calculate the actual amount of oil sealed X. However, this is not limited to this, and for example, two timings while the submersible pump 10 is stopped may be set as the first time point and the second time point. If a predetermined temperature change occurs between the first time point and the second time point, the actual amount of oil sealed X can be calculated appropriately.

Furthermore, if a predetermined temperature change (temperature change between the first time point, the second time point, and n) occurs before the submersible pump 10 starts operating, the actual oil amount X can be calculated, and the amount of oil leakage or flooding in the oil chamber can be calculated. As a result, it is possible to check whether oil leakage or flooding in the oil chamber has occurred before the submersible pump 10 starts operating.

In each embodiment, the pressure in the oil chamber is shown as the pressure in the space portion of the oil chamber, but the pressure in the oil portion (including the liquid portion in the event of flooding) where the pressure is balanced with the space portion may also be detected.

The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The elements of each embodiment, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those exemplified, and may be modified as appropriate. Furthermore, configurations shown in different embodiments may be partially substituted or combined.

10...Submersible pump, 11...Motor, 12...Rotating shaft, 13...Oil chamber, 14...Mechanical seal (shaft seal device), 15...Pump chamber, 16...Impeller, 110...Pressure sensor, 120...Space temperature sensor, 130...Oil temperature sensor, M100...Oil chamber monitoring method

Claims (11)

An oil chamber monitoring device for monitoring an oil chamber in which oil is sealed to be supplied to a mechanical seal of an underwater pump, comprising:
a pressure sensor that detects the pressure in the oil chamber;
a space temperature sensor that detects a space temperature in the oil chamber;
an oil temperature sensor for detecting an oil temperature in the oil chamber;
a calculation means for calculating an amount of oil leakage or an amount of water ingress from the oil chamber from a change in a spatial volume and an oil volume of the oil chamber between the first time point and the second time point, based on a first pressure which is the pressure, a first space temperature which is the space temperature, and a first oil temperature which is the oil temperature at a first time point, and a second pressure which is the pressure, a second space temperature which is the space temperature, and a second oil temperature which is the oil temperature at a second time point.
Oil chamber monitoring device. The calculation means is
calculating a spatial volume of the oil chamber at the second time point relative to the first time point using the first pressure and the first space temperature, and the second pressure and the second space temperature;
calculating an oil volume of the oil chamber at the second point in time relative to the first point in time using the first oil temperature and the second oil temperature;
2. The oil chamber monitoring device of claim 1. the calculation means calculates an amount of oil leakage or an amount of water flooding in the oil chamber based on a spatial volume of the oil chamber at the second time point relative to the first time point, an oil volume of the oil chamber at the second time point relative to the first time point, and a volume of the oil chamber.
3. The oil chamber monitoring device of claim 2. The spatial volume of the oil chamber is calculated using Boyle's law.
2. The oil chamber monitoring device of claim 1. The oil volume of the oil chamber is calculated based on the oil expansion coefficient of the oil.
2. The oil chamber monitoring device of claim 1. The first time point is when the submersible pump is stopped,
The second time point is during operation of the submersible pump.
2. The oil chamber monitoring device of claim 1. The oil chamber may be provided with an actual oil amount calculation means for calculating an actual amount of oil actually sealed in the oil chamber based on the pressure detected by the pressure sensor, assuming that a preset amount of oil is sealed in the oil chamber.
2. The oil chamber monitoring device of claim 1. The actual amount of oil filled is calculated according to a predetermined temperature change.
8. An oil chamber monitoring device as claimed in claim 7. The actual amount of oil filled is calculated while the submersible pump is stopped.
9. The oil chamber monitoring device of claim 8. An oil chamber monitoring device according to any one of claims 1 to 9;
A motor;
A rotating shaft that rotates by driving the motor;
an impeller that rotates in the pump chamber in association with the rotation of the rotating shaft to draw in liquid from the suction port and generate a flow toward the discharge port;
Submersible pump. An oil chamber monitoring method performed by an oil chamber monitoring device that monitors an oil chamber in which oil to be supplied to a mechanical seal of an underwater pump is sealed, comprising:
acquiring a pressure in the oil chamber detected by a pressure sensor;
acquiring a space temperature of the oil chamber detected by a space temperature sensor;
acquiring an oil temperature in the oil chamber detected by an oil temperature sensor;
calculating an amount of oil leakage or an amount of water ingress from the oil chamber from a change in a spatial volume and an oil volume of the oil chamber between the first time point and the second time point based on a first pressure which is the pressure, a first space temperature which is the space temperature, and a first oil temperature which is the oil temperature at a first time point, and a second pressure which is the pressure, a second space temperature which is the space temperature, and a second oil temperature which is the oil temperature at a second time point.
Oil chamber monitoring method.

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