JP6853733B2 - Water supply system and water supply method - Google Patents

Description

The present invention relates to a water supply system and a water supply method for supplying water from a water absorption tank to a water discharge tank.

At a pumping station, a plurality of pumps are used to pump water from a water suction tank to a water discharge tank, and at a drainage pumping station, a plurality of drainage pumps are used to drain water from a water suction tank to a water discharge tank. In these pumping stations, it is common that the number of pumps in operation increases as the water level and flow rate increase, and the pumps operate continuously until the water level and flow rate reach the target values.

Japanese Unexamined Patent Publication No. 2014-178816

When the pump is operated as described above, the operating time of the pump becomes longer than necessary and the power consumption increases. Then, when the maximum demand power is determined based on the peak power, the electricity bill will increase.
The present invention has been made in view of such problems, and an object of the present invention is to provide a water supply system and a water supply method capable of reducing electric power.

According to one aspect of the present invention, a plurality of pumps that send water in the water absorption tank to the water discharge tank, a water absorption tank water level gauge that measures the water level of the water absorption tank, and a water discharge tank water level that measures the water level of the water discharge tank. A meter and a control unit for controlling the start / stop of each of the plurality of pumps are provided, and the control unit should send water at predetermined time intervals based on the water level of the water absorption tank and the water level of the water discharge tank. The total amount of water is calculated, and based on the calculated total amount of water to be sent at the predetermined time interval, the time for the pump to be the final unit to operate at the predetermined time interval is calculated, and the pump to be the final unit is calculated. Is provided, a water supply system is provided in which the pump of the final unit is started to operate when the pump becomes operable, and then one pump is stopped when the time required for the pump of the final unit to operate has elapsed.

It is desirable that the one pump is different from the final pump which is started by the control unit.

The control unit may determine that the pump, which is the final unit, can be operated when the actual head based on the water level of the water absorption tank and the water level of the water discharge tank is not in the region where cavitation occurs.

The control unit may stop the one pump by adjusting the opening degree of the discharge valve in the one pump, the rotation speed of the impeller and / or the angle of the pump blade.

The plurality of pumps include pumps having different capacities, and the control unit calculates the time to be operated by the final pump when a pump having a certain capacity is set as the final pump, for each pump capacity. Based on the calculated time for the final pump to operate, the average power of the plurality of pumps at the predetermined time interval is calculated for each pump capacity, and the final pump can be operated. Then, the pump which is the final unit may be started to operate, and then the pump having the capacity to minimize the average power may be stopped as the one pump.

The water supply system is provided in a water pumping station, the pump is a water pump, and the control unit is based on the water level of the water absorption tank and the water level of the water discharge tank at a time interval preceding the predetermined time interval. The total amount of water flowing out of the spout tank and the total amount of water stored in the spout tank are calculated, and the calculated total amount of water flowing out of the spout tank and the water stored in the spout tank are calculated. Based on the total amount, the total amount of water to be sent may be calculated at the predetermined time interval.

The water supply system is provided in a drainage pump station, the pump is a drainage pump, and the control unit is based on the water level of the water absorption tank and the water level of the water discharge tank at a time interval preceding the predetermined time interval. The total amount of water drained by the plurality of pumps and the total amount of water stored in the water suction tank are calculated, and the calculated total amount of water flowing out of the water discharge tank and the water stored in the water discharge tank are calculated. The total amount of water to be pumped at the predetermined time interval may be calculated based on the total amount of water.

According to another aspect of the present invention, it is a water feeding method in which water in a water absorption tank is sent to a water discharge tank by using a plurality of pumps, and at predetermined time intervals based on the water level of the water absorption tank and the water level of the water discharge tank. The total amount of water to be sent is calculated, and based on the calculated total amount of water to be sent at the predetermined time interval, the time for the pump to be the final unit to operate at the predetermined time interval is calculated, and the final unit is calculated. A water feeding method is provided in which the pump of the final unit is started when the pump becomes operable, and then one pump is stopped when the time required for the pump of the final unit to operate elapses.

The final unit is operated for the time that the final unit should operate at a predetermined time interval, and then one pump is stopped. Therefore, the power consumption of a plurality of pumps can be reduced, and the electricity bill can be reduced.

The schematic block diagram of the water supply system 100 which concerns on 1st Embodiment. The flowchart which shows an example of the processing operation of the water supply system 100 in 1st Embodiment. The figure which shows QH characteristic schematically. The flowchart which shows an example of the processing operation of the water supply system 100 following FIG. The figure which shows typically the time change of on / off in three pumps 1. The figure which shows typically the time change of on / off in three pumps 1. The flowchart which shows an example of the processing operation of the water supply system 100 in 2nd Embodiment. The figure which shows the relationship between the discharge amount (horizontal axis), the shaft power P, and the total head H. The figure which shows the relationship between the discharge amount (horizontal axis), the shaft power P, and the total head H. The figure which shows the relationship between the discharge amount (horizontal axis), the shaft power P, and the total head H. The schematic block diagram of the water supply system 101 which concerns on 3rd Embodiment. The flowchart which shows an example of the processing operation of the water supply system 101 in 3rd Embodiment.

Hereinafter, embodiments according to the present invention will be specifically described with reference to the drawings.

(First Embodiment)
FIG. 1 is a schematic configuration diagram of a water supply system 100 according to the first embodiment. This water supply system 100 is provided at a pumping station. The water supply system 100 includes a plurality of pumps 1 (three in this embodiment), a water absorption tank water level gauge 2, a water discharge tank water level gauge 3, a flow meter 4, and a control unit 5.

Each of the plurality of pumps 1 pumps (sends) the water in the water absorption tank 11 to the water discharge tank 12. The pump 1 may be able to adjust the opening degree of the discharge valve (not shown), and the larger the opening degree, the larger the pumping amount. Further, the pump 1 may be able to adjust the rotation speed of the impeller (not shown), and the larger the rotation speed, the larger the pumping amount. Further, the pump 1 may be able to adjust the angle of the pump blades (not shown), and the larger the angle, the larger the amount of pumped water.

In the first embodiment, it is assumed that the capacities of all the pumps 1 are equal. As a matter of course, the larger the number of pumps 1 to be operated, the larger the power consumption, and when all the pumps 1 are operated, the power consumption is maximized.

The water absorption tank water level gauge 2 is provided in the water absorption tank 11 and measures the water level of the water absorption tank 11. The measurement result is notified to the control unit 5.
The water discharge tank water level meter 3 is provided in the water discharge tank 12 and measures the water level of the water discharge tank 12. The measurement result is notified to the control unit 5.
The flow meter 4 is provided on the drain side of the water discharge tank 12 and measures the flow rate of water discharged from the water discharge tank 12. The measurement result is notified to the control unit 5.

The control unit 5 performs calculations necessary for controlling the pump 1 based on the water level of the water absorption tank 11, the water level of the water discharge tank 12, and the flow rate of the water discharged from the water discharge tank 12. Then, the control unit 5 switches the operation / stop of the pump 1 at an appropriate timing based on the result of the calculation. At least a part of the operation of the control unit 5 may be performed by the processor executing a predetermined program.

^{Specifically, the control unit 5 sets the total amount of water A [m 3} ] pumped by the three pumps 1 and the spout tank at each preset time interval (hereinafter referred to as 30 minutes) for the same 30 minutes. The total amount of water B [m ³ ] flowing out of 12 and the total amount of water C [m ³ ] stored in the spout tank 12 are calculated, and based on these, the total amount of water to be pumped in the following 30 minutes D [m ^3]. ] Is calculated. Then, when the pump 1 which is the final unit (third unit in the present embodiment) becomes operable in the following 30 minutes, the final unit is operated for the required time and then stopped, which is an intermittent operation. I do. The details will be described below.

FIG. 2 is a flowchart showing an example of the processing operation of the water supply system 100 in the first embodiment. The process of FIG. 2 is performed when a predetermined 30 minutes have elapsed.

The control unit 5 is based on the water level measured by the water absorption tank water level gauge 2 (water absorption tank water level) and the water level measured by the water discharge tank water level gauge 3 (water discharge tank water level), and the water pumped by the three pumps 1 in 30 minutes. The total amount A [m ³ ] is calculated (step S1). Specifically, do as follows.

First, the control unit 5 calculates the actual head from the difference between the outer water level based on the water discharge tank water level and the inner water level based on the water absorption tank water level. Subsequently, the control unit 5 calculates the resistance characteristic in consideration of the pipeline loss resistance, and calculates the pumping flow rate Q0 [m ³ / s] per pump 1 from the QH characteristic stored in advance. To do. The QH characteristics of the pump 1 also depend on the opening degree of the discharge valve, the rotation speed of the impeller, the angle of the pump blade, and the like. When these can be adjusted, the control unit 5 stores the QH characteristics in advance for each opening degree of the discharge valve and the like.

FIG. 3 is a diagram schematically showing the QH characteristics. The vertical axis represents the total head H [m], and the horizontal axis Q [m ³ / s] represents the flow rate. The curved shape of the resistance characteristic is determined by the conduit loss resistance, and the intercept on the vertical axis corresponds to the calculated actual head. The intersection of the curve showing the resistance characteristic and the curve showing the QH characteristic becomes the operating point, and the water supply flow rate Q0 [m ³ / s] per pump 1 is determined. Then, the total amount A [m ³ ] of the water pumped by the pump 1 is obtained by applying the following equation.
A [m ³ ] = ΣQ0 [m ³ / s] x ti [s]
In addition, ti (i = 1 to 3 in this embodiment) is the operation time of the i-th pump pump 1.

Returning to FIG. 2, the control unit 5 calculates the total amount C of the water stored in the water discharge tank 12 in 30 minutes based on the measurement result of the water discharge tank water level gauge 3 (step S2). Specifically, the following formula is applied from the water discharge tank water level h0 [m] 30 minutes ago, the current water discharge tank water level h1 and the area S [m ² ] of the water discharge tank 12, and the control unit 5 applies the water discharge tank in 30 minutes. The total amount C of the water stored in 12 is calculated.
C [m ³ ] = (h0 [m] -h1 [m]) x S [m ² ]

Next, the control unit 5 calculates the total amount B of the water flowing out from the water discharge tank 12 (step S3). As an example, the control unit 5 can calculate ^{the total amount B [m 3} ] of the water flowing out from the water discharge tank 12 in 30 minutes using the measurement result of the flow meter 4. Specifically, assuming that the measured value of the flow meter 4 at a certain time t is F (t) [m ³ / s], the total amount B of water flowing out from the water discharge tank 12 is calculated by applying the following equation.

As another example, the shape of the water discharge tank 12 (specifically, the area S [m ² ] of the water discharge tank 12), the water level change L [m] of the water discharge tank 12 in 30 minutes, and the pump 1 calculated in step S1. From the total amount of water pumped by A [m ³ ], the control unit 5 may calculate the total amount B of water flowing out from the water discharge tank 12 by applying the following equation.
B [m ³ ] = A [m ³ ] -C [m ³ ]

Then, the control unit 5 sets the total amount B of the water flowing out from the water discharge tank 12 as the total amount D [m ³ ] of the water to be pumped in the next 30 minutes.

FIG. 4 is a flowchart showing an example of the processing operation of the water supply system 100 following FIG. The process of FIG. 4 is performed for the following 30 minutes after the process of FIG. 2 is completed for the preceding 30 minutes.

When the two pumps 1 are in operation (YES in step S11), the control unit 5 calculates the actual head (step S12). Subsequently, the control unit 5 determines that the third pump 1 can be operated if the calculated actual head is not in the region where cavitation occurs (YES in step S13). When the third pump 1 is operable and the flow rate of the pump 1 can be adjusted by adjusting the discharge valve opening degree, the rotation speed and / or the pump blade angle, the control unit 5 controls the flow rate of the pump 1. The adjustment amount is calculated (step S14).

Further, the control unit 5 calculates the time (operating time) T that the third pump should operate (step S15). Specifically, the total amount of water to be pumped in 30 minutes D [m ³ ], the amount of water pumped by the other two pumps 1 in 30 minutes E [m ³ ], and the instantaneous amount of the third pump 1 Using the flow rate f [m ³ / s], the control unit 5 calculates the operation time T by applying the following equation.
T [s] = (D [m ³ ] -E [m ³ ]) / f [s]

Here, the total amount D [m ³ ] of water to be pumped in 30 minutes was calculated in step S4 of FIG. ^{The pumping amount E [m 3} ] in 30 minutes by the other two pumps 1 is obtained from the instantaneous flow rate of each pump 1. The instantaneous flow rate of each pump 1 is determined from the resistance characteristics and QH characteristics of the pump 1 as described with reference to FIG.

Subsequently, the control unit 5 starts the operation of the third pump 1 (step S16). When the operation time T of the third pump has elapsed from the start of the operation, the control unit 5 stops the third pump 1 (step S17), and does not pump water by the third pump any more. The pump 1 may be stopped by adjusting the opening degree of the discharge valve, the rotation speed of the impeller and / or the angle of the pump blade. In this way, the third pump 1 is operated for a required time in a predetermined 30 minutes. Therefore, power consumption can be minimized.

The pump 1 (“third” in step S16) that started operation in step S16 may match the pump 1 (“third”” in step S17 that stops in step S17. It is desirable that (FIG. 5A) does not match (FIG. 5B).

5A and 5B schematically show the on / off time change of the three pumps 1. The three pumps 1 are referred to as pumps 1A to 1C.

In FIG. 5A, the operation of the pump 1C is started as the third unit (final unit) at time t1, and after the operation time T has elapsed, the pump 1C is also stopped at time t2. At time t3 after that, the operation of the pump 1C was started as the third unit (final unit), and at time t4, the pump 1C was also stopped. If the operation / stop of only one pump 1C is frequently switched in this way, the load of only this pump 1C becomes large and deterioration may progress.

On the other hand, in FIG. 5B, the operation of the pump 1C is started as the third unit (final unit) at time t1, and after the operation time T has elapsed, another pump 1A is stopped as the third unit at time t2. To do. After that, at time t3, the operation of the pump 1A is started as the third unit, and at time t4, the different pumps 1B are stopped. By performing such rotation, all the pumps 1 can be operated in a well-balanced manner.

As described above, in the first embodiment, it is based on the total amount B [m ³ ] of the water flowing out from the spout tank 12 and the total amount C [m ³ ] of the water stored in the spout tank 12 at the preceding specific time interval. Then, the control unit 5 calculates ^{the total amount D [m 3} ] of the water to be pumped at the subsequent specific time interval. Then, the time to be operated by the final pump 1 is calculated at the subsequent specific time interval, and the control unit 5 operates the final pump 1 for the operation time, and then one pump. Stop 1 In this way, the required operating time is calculated for each time interval, and the pump, which is the final unit, is operated for the required operating time, so that the electric power can be suppressed.

(Second embodiment)
In the first embodiment described above, it was assumed that the capacities of all pumps 1 were equal. On the other hand, the second embodiment described below includes the pump 1 having different capacities. In the following, for simplification of the description, it is assumed that the three pumps 1 include a large pump having a large capacity (instantaneous flow rate) and a small pump having a small instantaneous flow rate, and are different from the first embodiment. The explanation will focus on the points.

FIG. 6 is a flowchart showing an example of the processing operation of the water supply system 100 in the second embodiment, and corresponds to FIG. 4 in the first embodiment. Steps S21 to S23 in FIG. 6 are the same as steps S11 to S13 in FIG. 4, respectively.

When the third pump 1 is operable and the flow rate of the pump 1 can be adjusted by adjusting the discharge valve opening degree, the rotation speed and / or the pump blade angle, the control unit 5 is large in the pump 1. The flow rate adjustment amount of the pump and the small pump is calculated (step S24). Further, the control unit 5 calculates the shaft powers of the large pump and the small pump based on the QH-shaft power characteristics stored in advance (step S25). Since the shaft power of the pump has different characteristics depending on the type and specific speed of the pump, the control unit 5 stores the characteristics peculiar to the pump.

For example, in the case of a centrifugal pump, the relationship between the discharge amount (horizontal axis), the shaft power P, and the total head H is as shown in FIG. 6A. In the case of an axial flow pump, the relationship between the discharge amount (horizontal axis), the axial power P, and the total head H is as shown in FIG. 6B. In the case of a mixed flow pump, the relationship between the discharge amount (horizontal axis), the shaft power P, and the total head H is as shown in FIG. 6A.

Subsequently, the control unit 5 calculates the time Tl for operating the final unit when the large pump is the final unit and the time Ts for operating the final unit when the small pump is the final unit. (Step S26).

Further, the control unit 5 calculates the average power Pl when the large pump is the final unit based on the time Tl, and calculates the average power Ps when the small pump is the final unit based on the time Ts (). Step S27). The average power Pl is the average power in 30 minutes when the two pumps 1 are operated for 30 minutes and the large pump, which is the final unit, is operated for the operating time Tl. The power consumption by the final unit is obtained by dividing the product of the shaft power calculated in step S25 and the operating time Tl by 30 minutes. The average power Ps is the average power in 30 minutes when the two pumps 1 are operated for 30 minutes and the small pump, which is the final unit, is operated for the operation time Ts. The power consumption by the final unit is obtained by dividing the product of the shaft power calculated in step S25 and the operating time Ts by 30 minutes.

Subsequently, the control unit 5 starts the operation of the third pump 1 (step S29). Then, when Pl <Ps (YES in step S29), when the operation time Tl elapses from the start of the operation of the third unit, the control unit 5 stops one large pump (step S30a), and the larger pump is stopped. Do not pump water. On the other hand, when Pl ≧ Ps (NO in step S29), when the operation time Ts elapses from the start of the operation of the third unit, the control unit 5 stops one small pump (step S30b), and the small pump beyond that. Do not pump water.

As described above, in the second embodiment, the average power when the large pump is the final unit and the average power when the small pump is the final unit are calculated, so that the average power is appropriately finalized so as to be small. You can select the unit.

The capacities of the plurality of pumps 1 may be different from each other. Even in that case, the operating time and the average power when the pump 1 having the capacity in steps S26 and S27 of FIG. 6 is used as the final unit are calculated for each capacity, and the pump 1 having the capacity to minimize the average power is finally used. It may be selected as the unit and stopped in steps S30a and S30b.

(Third Embodiment)
The first and second embodiments described above have in mind the water supply system 100 provided at the pumping station. The water supply system 101 described below is provided at the drainage pumping station. Hereinafter, the differences from the first embodiment will be mainly described.

FIG. 7 is a schematic configuration diagram of the water supply system 101 according to the third embodiment. This water supply system 101 is provided at a drainage pumping station. The water supply system 101 includes a plurality of (three units in this embodiment) drainage pumps 1', a water absorption tank water level gauge 2, a water discharge tank water level gauge 3, and a control unit 5. Compared with FIG. 1, the difference is that the drainage pump 1'is used instead of the pump 1 and the flow meter 4 in FIG. 1 is not required.

^{In the water supply system 101 of the present embodiment, the total amount of water L [m 3} ] and the water absorption tank drained by the three drainage pumps 1'in the same 30 minutes at preset time intervals (hereinafter referred to as 30 minutes). The total amount of water M [m ³ ] stored in 11 is calculated, and based on these, the total amount of water N [m ³ ] to be drained in the following 30 minutes is calculated. Then, when the final unit (third drainage pump 1'in this embodiment), which consumes the maximum power in the following 30 minutes, becomes operable, the final unit is operated for the required time, and then the final unit is operated. Performs an intermittent operation of stopping. The details will be described below.

FIG. 8 is a flowchart showing an example of the processing operation of the water supply system 101 according to the third embodiment. The process of FIG. 8 is performed when a predetermined 30 minutes have elapsed.

The control unit 5 is the water drained by the three drainage pumps 1'in 30 minutes based on the water level measured by the water absorption tank water level gauge 2 (water absorption tank water level) and the water level measured by the water discharge tank water level gauge 3 (water discharge tank water level). The total amount L [m ³ ] of is calculated (step S31). Specifically, do as follows.

First, the control unit 5 calculates the actual head from the difference between the outer water level based on the water discharge tank water level and the inner water level based on the water absorption tank water level. Subsequently, the control unit 5 calculates the resistance characteristic in consideration of the pipeline loss resistance, and calculates the drainage flow rate Q1 [m ³ / s] per unit of the drainage pump 1'from the QH characteristic stored in advance. Calculate (see FIG. 3). Then, the total amount L [m ³ ] of the water drained by the drainage pump 1'is obtained by applying the following equation.
L [m ³ ] = ΣQ1 [m ³ / s] × ti [s]
In addition, ti (i = 1 to 3 in this embodiment) is the operation time of the i-th drainage pump 1'.

Further, the control unit 5 calculates the total amount M of the water stored in the water absorption tank 11 in 30 minutes based on the measurement result of the water absorption tank water level gauge 2 (step S32). Specifically, the following formula is applied from the water absorption tank water level h3 [m] 30 minutes ago, the current water absorption tank water level h4, and the area S1 [m ² ] of the water absorption tank 11, and the control unit 5 takes 30 minutes for the water absorption tank. The total amount C of the water stored in 11 is calculated.
M [m ³ ] = (h3 [m] -h4 [m]) x S1 [m ² ]

^{Then, the control unit 5 calculates the total amount N [m 3} ] of water to be drained in the next 30 minutes by applying the following equation (step S33).
N [m ³ ] = L [m ³ ] + C [m ³ ]

After that, the operation and stop of the final unit are controlled in the same manner as in FIG. 4 in the first embodiment.

As described above, in the third embodiment, the electric power can be suppressed even in the drainage pumping station. When a plurality of drainage pumps 1'include different capacities, the same procedure as in the second embodiment may be applied.

The above-described embodiment is described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention belongs to carry out the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments and should be the broadest scope according to the technical ideas defined by the claims.

1 Pumping pump 1'Drainage pump 2 Water absorption tank water level gauge 3 Water discharge tank water level gauge 4 Flow meter 5 Control unit 11 Water absorption tank 12 Water discharge tank 100,101 Water supply system

Claims (9)

Multiple pumps that send the water in the water absorption tank to the water discharge tank,
A water absorption tank water level gauge that measures the water level of the water absorption tank,
A water discharge tank water level gauge that measures the water level of the water discharge tank,
A control unit that controls the start / stop of each of the plurality of pumps is provided.
The control unit
Based on the water level of the water absorption tank and the water level of the water discharge tank, the total amount of water to be sent at predetermined time intervals is calculated.
Based on the calculated total amount of water to be sent at the predetermined time interval, the time for the final pump to operate at the predetermined time interval is calculated.
When the final pump becomes operational, the final pump is started to operate.
After that, when the time required for the final pump to operate has elapsed, the water supply system stops the final pump. Multiple pumps that send the water in the water absorption tank to the water discharge tank,
A water absorption tank water level gauge that measures the water level of the water absorption tank,
A water discharge tank water level gauge that measures the water level of the water discharge tank,
A control unit that controls the start / stop of each of the plurality of pumps is provided.
The control unit
Based on the water level of the water absorption tank and the water level of the water discharge tank, the total amount of water to be sent at predetermined time intervals is calculated.
Based on the calculated total amount of water to be sent at the predetermined time interval, the time for the final pump to operate at the predetermined time interval is calculated.
When the final pump becomes operational, the final pump is started to operate.
After that, when the time required for the final pump to operate elapses , the water supply system stops the pump different from the final pump without stopping the final pump. The control unit determines that the pump, which is the final unit, can be operated when the actual head based on the water level of the water absorption tank and the water level of the water discharge tank is not in the region where cavitation occurs, according to claim 1 or 2. Described water supply system. Wherein, the opening degree of the discharge valve in the pump to be the final Unit, by adjusting the angle of the rotational speed and / or pump impeller of the impeller, the pump is stopped to be the final Units in claim 1 The water supply system described. The control unit stops a pump different from the final unit by adjusting the opening degree of the discharge valve, the rotation speed of the impeller, and / or the angle of the pump blade in the pump different from the final unit. The water supply system according to 2. The water supply system is installed at the pumping station.
The pump is a pumping pump
The control unit
Based on the water level of the water absorption tank and the water level of the water discharge tank, the total amount of water flowing out of the water discharge tank at the time interval preceding the predetermined time interval and the total amount of water stored in the water discharge tank are calculated. And
Claims 1 to 5 for calculating the total amount of water to be sent at the predetermined time interval based on the calculated total amount of water flowing out of the water discharge tank and the total amount of water stored in the water discharge tank. The water supply system described in either. The water supply system is installed at the drainage pumping station.
The pump is a drainage pump
The control unit
Based on the water level of the water absorption tank and the water level of the water discharge tank, the total amount of water drained by the plurality of pumps at the time interval preceding the predetermined time interval and the total amount of water stored in the water absorption tank are calculated. Calculate and
Claims 1 to 5 for calculating the total amount of water to be sent at the predetermined time interval based on the calculated total amount of water flowing out of the water discharge tank and the total amount of water stored in the water discharge tank. The water supply system described in either. This is a water supply method in which the water in the water absorption tank is sent to the water discharge tank using a plurality of pumps .
Based on the water level of the water absorption tank and the water level of the water discharge tank, the total amount of water to be sent at predetermined time intervals is calculated.
Based on the calculated total amount of water to be sent at the predetermined time interval, the time for the final pump to operate at the predetermined time interval is calculated.
When the final pump becomes operational, the final pump is started to operate.
After that, when the time for the final pump to operate has elapsed, the water supply method for stopping the final pump. This is a water supply method in which the water in the water absorption tank is sent to the water discharge tank using a plurality of pumps.
Based on the water level of the water absorption tank and the water level of the water discharge tank, the total amount of water to be sent at predetermined time intervals is calculated.
Based on the calculated total amount of water to be sent at the predetermined time interval, the time for the final pump to operate at the predetermined time interval is calculated.
When the final pump becomes operational, the final pump is started to operate.
After that, when the time for the final pump to operate elapses, the water supply method in which the pump different from the final pump is stopped without stopping the final pump.

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