JP2023092549A - Device and method of detecting fall of water and draining system - Google Patents

Abstract

To provide a device and a method of detecting fall of water from an operating pump more accurately, and to provide a draining system including such the device of detecting fall of water.SOLUTION: A draining system includes: a pump with an impeller; a drive source for rotatably driving the impeller of the pump; a thermometer for measuring a temperature of an exhaust gas discharged from the drive source; and a detector for fall of water that detects fall of water on the basis of a rate of increase in temperature of the exhaust gas per unit time.SELECTED DRAWING: Figure 1

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drainage system, a water fall detection device, and a water fall detection method, and more particularly, to a water drainage system having a water fall detection function that detects liquid dropout from a pump during operation.

Even during steady operation, the pump may fall into water for certain reasons. If the water falls, the impeller may spin and the underwater bearing may be damaged. In view of this, devices have been developed for detecting water falling in pumps during operation.

For example, Patent Literature 1 discloses a pump device. According to this technique, it is possible to detect whether liquid exists in the pump during steady operation.

Japanese Patent No. 4854478

In view of the above circumstances, it is an object of the present invention to provide a water fall detection device and a water fall detection method that more accurately detect water fall from inside a pump during operation, and a drainage system equipped with such a water fall detection device. and

According to one aspect of the present invention, a pump having an impeller, a drive source that rotationally drives the impeller of the pump, a thermometer that measures the temperature of exhaust gas discharged from the drive source, and the temperature of the exhaust gas a water fall detection unit that detects a water fall based on the rate of rise per unit time of the water discharge system.

The falling water detection unit detects falling water based on the rate of increase in temperature of the exhaust gas per unit time until a predetermined time elapses after the rotational speed of the impeller reaches a specified speed, and detects the rotational speed of the impeller. Falling into the water may be detected based on the temperature of the exhaust gas after the predetermined time has passed since the speed reaches the specified speed.

The falling water detection unit detects falling water based on a comparison between the temperature rise rate of the exhaust gas per unit time and a first specified value for a predetermined time after the rotational speed of the impeller reaches a specified speed. After the predetermined time has elapsed since the rotational speed of the impeller reached a specified speed, falling into the water may be detected based on a comparison between the temperature of the exhaust gas and a second specified value.

The overwater detection unit may perform the overwater detection based on an increase rate per unit time of the temperature of the exhaust gas when the rotational speed of the impeller reaches a specified speed.

According to another aspect of the present invention, there is provided a pump having an impeller, a drive source that rotationally drives the impeller of the pump, a thermometer that measures the temperature of exhaust gas discharged from the drive source, and the impeller. a falling water detection unit that detects falling into the water based on the temperature of the exhaust gas after a predetermined time has elapsed since the rotation speed of the exhaust gas reaches a specified speed.

The overwater detection unit may measure time based on the time when the rotational speed of the impeller reaches a specified speed, and detect overwater based on the temperature of the exhaust gas after the predetermined time has elapsed.

By detecting falling water based on the temperature of the exhaust gas after a predetermined time has elapsed since the rotational speed of the impeller reaches a specified speed, it is possible to suppress erroneous detection due to a delay in the temperature rise of the exhaust gas. good.

Advantageous Effects of Invention According to the drainage system, the drainage system control device, and the drainage system control method of the present invention, it is possible to detect falling water from the pump during operation and prevent erroneous detection of falling water.

The figure which shows schematic structure of the drainage system in embodiment of this invention. The graph which shows typically a mode that the temperature of exhaust gas rises. 5 is a flow chart showing an example of a procedure for detecting falling into the water based on the rate of increase in exhaust gas temperature per unit time; 5 is a flowchart showing an example of a procedure for detecting falling into the water based on the temperature of exhaust gas; 5 is a flowchart showing an example of a procedure for detecting falling into the water based on the temperature of exhaust gas and its rate of increase per unit time;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments according to the present invention will be specifically described with reference to the drawings.

(First embodiment)
Drawing 1 is a figure showing a schematic structure of drainage system 1 in an embodiment of the present invention.

The drainage system 1 includes a pump 10 that transfers liquid from a suction water tank 11 to a discharge water tank 18, a suction pipe 13 that communicates the pump 10 and the suction water tank 11, and a discharge pipe 15 that communicates the pump 10 and the discharge water tank 18. , and a prime mover 5 as a drive source for driving the pump 10 .

The pump 10 has an impeller (not shown) housed in the pump 10 . The impeller is connected to a speed reducer 6 via a rotating shaft, and the speed reducer 6 is connected to the prime mover 5 . This pump 10 is a so-called horizontal-shaft pump whose rotating shaft extends horizontally. Exhaust gas is discharged from the internal combustion engine of the prime mover 5 when the prime mover 5 rotates the impeller. Exhaust gas is released to the atmosphere from an exhaust gas pipe 5a connected to the prime mover 5. As shown in FIG. The higher the load on the prime mover 5, the higher the temperature of the exhaust gas.

The suction pipe 13 extends vertically and its suction port 12 is located in the liquid in the suction water tank 11 . The pump 10 is arranged above the level of the liquid in the suction water tank 11 and is installed on the installation floor 20 constituting the upper part of the suction water tank 11 via a frame 21 . A downstream portion of the suction pipe 13 is a bent pipe portion, whereby the suction pipe 13 and the pump 10 are smoothly connected.

The discharge pipe 15 has a discharge port 16 that opens in the discharge water tank 18 . The discharge port 16 is positioned lower than the pump 10 and higher than the suction port 12 . The ejection port 16 is provided with a flap valve 17 for preventing backflow of the liquid transferred to the ejection water tank 18 .

As can be seen from FIG. 1, suction pipe 13, pump 10 and discharge pipe 15 collectively form a siphon-type passage. A full-water detector 30 having an electrode rod inside is provided on the upper portion of the pump 10, and the full-water detector 30 detects whether the inside of the pump 10 is filled with liquid. Furthermore, the inside of the pump 10 communicates with a vacuum pump 31 via a full water detector 30 .

In such a configuration, when the drainage system 1 is started, first, after the discharge valve 14 is fully closed, the inside of the pump 10 is evacuated by the vacuum pump 31 to form a negative pressure, and the suction pipe 13 is raise the liquid level of When the full-water detector 30 detects that the inside of the pump 10 is filled with liquid, the motor 5 rotates the impeller and opens the discharge valve 14 , whereby the liquid is discharged from the suction water tank 11 to the discharge water tank 18 . transferred to

As described above, the pump 10 is positioned higher than the liquid level of the suction water tank 11 . Therefore, if water falls during operation of the drainage system 1, the pump 10 may become unable to drain water or may be damaged. Therefore, in this embodiment, the falling water detector 2 detects falling into the water.

Specifically, the drainage system 1 includes a thermometer 3 , a speedometer 4 and a falling water detector 2 . The thermometer 3 and the falling water detection unit 2 constitute a falling water detection device.

The thermometer 3 is provided, for example, in the exhaust gas pipe 5a and measures the temperature of the exhaust gas discharged from the prime mover 5. As shown in FIG. The measured exhaust gas temperature is notified to the falling-in-water detection unit 2 . A speedometer 4 measures the rotational speed of the prime mover 5 . Since the rotation speed of the impeller is obtained by reducing the rotation speed of the prime mover 5 at a predetermined ratio by the speed reducer 6, it can be said that the speedometer 4 measures the rotation speed of the impeller. The measured rotation speed is notified to the falling-in-water detection unit 2 .

The falling water detector 2 is connected to a thermometer 3 and a speedometer 4, as shown in FIG. Then, the overwater detection unit 2 detects overwater based on the obtained temperature of the exhaust gas and also considering the rotation speed of the prime mover 5 (impeller) as necessary. When the water fall detection unit 2 determines that a water fall has occurred, it issues a command to the discharge valve 14 to close the discharge valve 14, stops the motor 5 to stop the operation of the drainage system 1, or issues an alarm. may

FIG. 2 is a graph schematically showing how the temperature of the above exhaust gas rises.

As shown in FIG. 2, during normal operation indicated by curve C1, that is, when water does not fall into the water, water is sucked up into pump 10 as pump 10 is started, so the load on prime mover 5 increases. Therefore, the temperature of exhaust gas rises to about 450 degrees. As indicated by the curve C2, when the motor 5 is started in a cold state, the initial temperature of the exhaust gas is low, so the temperature of the exhaust gas eventually rises to about 450 degrees, although it takes time.

On the other hand, when water falls as indicated by curve C3, water is not sucked up into pump 10, so the load on prime mover 5 does not increase so much. Therefore, the temperature of the exhaust gas rises only up to about 150 degrees.

Therefore, it is conceivable to detect falling into the water based on the temperature of the exhaust gas when the rotation speed of the impeller reaches a specified speed. For example, if the temperature of the exhaust gas is less than a specified temperature (for example, 200 degrees in FIG. 2), it may be determined that falling into the water has occurred.

However, when the prime mover 5 is started in a cold state, the rate of increase in exhaust gas temperature is slow. It may not have risen to In that case, there is a possibility that a fall in the water is erroneously detected even if the fall in the water does not actually occur.

Therefore, in the present embodiment, falling into the water is detected based on the increase rate per unit time of the temperature of the exhaust gas. As shown in FIG. 2, during normal operation, especially for a predetermined period after the start of the pump 10, regardless of whether or not the prime mover 5 is in a cold state at the time of start, the rate of increase in the temperature of the exhaust gas per unit time ( ΔT/dt) becomes a large value to some extent. On the other hand, at the time of falling into the water, the increase rate (ΔT/dt) of the exhaust gas temperature per unit time is not so large even in the same predetermined period.

That is, the rate of increase per unit time (ΔT/dt) of the exhaust gas temperature during normal operation is greater than the rate of increase per unit time (ΔT/dt) of the exhaust gas temperature during drowning. In this embodiment, this fact is used to detect falling into the water. Note that the unit time may be set arbitrarily, but can be set to about 5 seconds, for example. It is desirable that the prescribed value of the rise rate of the temperature of the exhaust gas per unit time, which is used as a criterion for judging whether or not the person is overboard, is determined to be clearly determined as being overboard.

FIG. 3 is a flow chart for explaining detection of falling into the water based on the rate of increase per unit time of the temperature of the exhaust gas described above.

First, the prime mover 5 is started (step S1). Then, when the rotation speed measured by the speedometer 4 reaches the specified speed (YES in step S2), the overwater detection unit 2 detects that the temperature rise rate (ΔT/dt) of the exhaust gas per unit time reaches the specified value. If it is less than (ΔT ₀ /dt) (YES in step S3), it is determined that the water falls (step S4), and the rate of increase (ΔT/d
t) is equal to or greater than the specified value (ΔT ₀ /dt) (NO in step S3), it is determined that there is no falling in the water (step S5).

Thus, in the first embodiment, falling into the water is detected based on the temperature rise rate of the exhaust gas. Therefore, even when the pump 10 is started while the prime mover 5 is cold, it is possible to accurately detect falling water.

(Second embodiment)
The above-described first embodiment is particularly effective because the rate of increase in the temperature of the exhaust gas per unit time differs significantly between normal operation and falling water within a predetermined period from the start of the prime mover 5 . However, as shown in FIG. 2, after a certain amount of time has passed since the prime mover 5 was started, the difference in the rate of increase in the exhaust gas temperature per unit time between normal operation and falling water becomes smaller (in both cases The temperature of the exhaust gas hardly rises), which may make it difficult to detect falling in the water based on the rate of rise.

On the other hand, as shown in FIG. 2, if a sufficient period of time (for example, time T2 in FIG. 2, about 60 seconds) has elapsed, even if the pump 10 is started with the prime mover 5 cold, the exhaust gas temperature will remain constant during normal operation. becomes high, and the temperature of exhaust gas is low when falling into the water. The second embodiment focuses on this point.

FIG. 4 is a flowchart for explaining detection of falling into the water based on the temperature of exhaust gas described above.

First, the prime mover 5 is started (step S11). Then, when the rotational speed measured by the speedometer 4 reaches the specified speed (YES in step S12), the overwater detector 2 measures time based on that time (step S13). If the temperature of the exhaust gas is equal to or lower than the specified temperature (YES in step S15) at or after the specified time has passed since the rotational speed reached the specified speed (YES in step S14), the overwater detection unit 2 determines that the temperature of the exhaust gas is below the specified temperature (YES in step S15). It is determined (step S16), and if the temperature of the exhaust gas is equal to or higher than the specified temperature (NO in step S15), it is determined that there is no falling water (step S17).

As described above, in the second embodiment, falling into the water is detected based on the exhaust gas temperature after the specified time has passed since the rotational speed reaches the specified speed. That is, until the specified time has elapsed after the rotation speed reaches the specified speed, the overwater detection based on the exhaust gas temperature is not performed. Therefore, even when the pump 10 is started with the prime mover 5 cold, erroneous detection due to a delay in the rise of the exhaust gas temperature can be suppressed, and falling into the water can be detected with high accuracy.

(Third Embodiment)
Falling into the water detection based on the temperature of the exhaust gas in the above-described second embodiment is performed after a specified time has passed since the rotation speed reaches the specified speed, and falling into the water is not detected until the specified time has passed.

Therefore, in the third embodiment described below, the above-described second embodiment is combined with the first embodiment so that falling into the water can be detected both before and after the specified time has passed.

FIG. 5 is a flowchart for explaining detection of falling into the water based on the temperature of the exhaust gas and its rate of increase per unit time.

First, the prime mover 5 is started (step S21). Then, when the rotational speed measured by the speedometer 4 reaches the specified speed (YES in step S22), the overwater detector 2 measures time based on that time (step S23).

Until the specified time elapses after the rotation speed reaches the specified speed (NO in step S24), the falling water detector 2, as described in the first embodiment, keeps the temperature of the exhaust gas at a rate of increase per unit time. Based on this, it detects falling water. That is, when the temperature rise rate of the exhaust gas per unit time (ΔT/dt) is less than the specified value (ΔT ₀ /dt), the falling water detection unit 2 detects that (step S25
YES), it is determined that the person has fallen into the water (step S26), and the rate of increase (ΔT/dt) is the specified value (ΔT ₀
/dt) (NO in step S25), it is determined that there is no fall in the water (step S27), and the determination is repeated until the specified time elapses.

After the stipulated time has passed since the rotation speed reached the stipulated speed (YES in step S24), the falling water detector 2 detects falling into the water based on the temperature of the exhaust gas, as described in the second embodiment. . That is, if the temperature of the exhaust gas is below the specified temperature (YES in step S28), the falling water detector 2 determines that the temperature of the exhaust gas is below the specified temperature (step S29), and if the temperature of the exhaust gas is above the specified temperature (NO in step S28). , it is determined that there is no fall in the water (step S30).

Thus, in the third embodiment, falling into the water is detected based on the rate of increase of the temperature of the exhaust gas per unit time until the specified time elapses after the rotation speed reaches the specified speed, and the specified time has passed. After that, it detects falling water based on the temperature of the exhaust gas. Therefore, even when the pump 10 is started with the prime mover 5 cold, falling into the water can be detected even before the exhaust gas temperature rises while suppressing erroneous detection due to a delay in the rise of the exhaust gas temperature.

In step S2 of FIG. 3, step S12 of FIG. 4 and step S22 of FIG. You can proceed to step.

The above-described embodiments are described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above-described embodiments can be naturally made by those skilled in the art, and the technical idea of the present invention can also be applied to other embodiments. Therefore, the present invention should not be limited to the described embodiments, but should have the broadest scope in accordance with the spirit defined by the claims.

1 Drainage system 2 Falling water detector 3 Thermometer 4 Speedometer 5 Motor 6 Reduction gear 10 Pump 11 Suction water tank 12 Suction port 13 Suction pipe 14 Discharge valve 15 Discharge pipe 16 Discharge port 17 Flap valve 18 Discharge water tank 20 Installation floor 21 Mounting frame 30 Full water detector 31 Vacuum pump

Claims (11)

a pump having an impeller;
a driving source that rotationally drives the impeller of the pump;
a thermometer for measuring the temperature of the exhaust gas discharged from the drive source;
and a water drop detection unit that detects water drop based on the rate of increase in the temperature of the exhaust gas per unit time. The falling-in-water detection unit
until a predetermined time has elapsed after the rotational speed of the impeller reaches a specified speed, detecting falling water based on the rate of increase in the temperature of the exhaust gas per unit time;
2. The drainage system according to claim 1, wherein falling water is detected based on the temperature of the exhaust gas after the predetermined time has passed since the rotation speed of the impeller reaches a specified speed. The falling-in-water detection unit
until a predetermined time elapses after the rotation speed of the impeller reaches a specified speed, detecting falling into the water based on a comparison between the temperature rise rate of the exhaust gas per unit time and a first specified value;
3. The drainage system according to claim 2, wherein after the predetermined time has passed since the rotation speed of the impeller reaches a specified speed, falling water is detected based on a comparison between the temperature of the exhaust gas and a second specified value. 4. The water falling detection unit according to claim 1, wherein the water falling detection unit performs the water falling detection based on a rate of increase in temperature of the exhaust gas per unit time when the rotational speed of the impeller reaches a specified speed. drainage system. a pump having an impeller;
a driving source that rotationally drives the impeller of the pump;
a thermometer for measuring the temperature of the exhaust gas discharged from the drive source;
a water drop detection unit that detects water drop based on the temperature of the exhaust gas after a predetermined time has elapsed since the rotation speed of the impeller reaches a specified speed. 6. The water falling detection unit according to claim 5, wherein the time is measured based on the time when the rotation speed of the impeller reaches a specified speed, and the water falling is detected based on the temperature of the exhaust gas after the predetermined time has elapsed. drainage system. 6. False detection due to a delay in the temperature rise of the exhaust gas is suppressed by detecting falling water based on the temperature of the exhaust gas after a predetermined time has elapsed since the rotational speed of the impeller reaches a specified speed. 7. Drainage system according to 6. a thermometer for measuring the temperature of the exhaust gas discharged from the drive source that rotationally drives the impeller of the pump;
and a falling water detection unit that detects falling into the water based on the rate of increase per unit time of the temperature of the exhaust gas. a thermometer for measuring the temperature of the exhaust gas discharged from the drive source that rotationally drives the impeller of the pump;
a falling water detecting device that detects falling into the water based on the temperature of the exhaust gas after a predetermined time has elapsed since the rotation speed of the impeller reaches a specified speed. a step of measuring the temperature of exhaust gas discharged from a driving source that rotationally drives an impeller of a pump;
and detecting falling into the water based on the rate of increase per unit time of the temperature of the exhaust gas. a step of measuring the temperature of exhaust gas discharged from a driving source that rotationally drives an impeller of a pump;
and detecting falling into the water based on the temperature of the exhaust gas after a predetermined time has passed since the rotation speed of the impeller reaches a specified speed.

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