JP2001050188A - Pressure water supply device and its driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge residual water in a pump and in the neighbourhood of the pump even in the case when the pump is left in a driving stop state as water is not used for a long period of time at the demand side. SOLUTION: An automatic valve 12 installed on a discharge pipe 13 is set in an open state for a constant period of time and a pump 4 is set temporarily in a starting state each time when a pump driving stop state continues for a specified period of time by a control means on an inverter INV so that water in the pump 4 and residing in the neighbourhood of it is discharged outside while the pump 4 is left in the driving stop state because no water is used on the demand side in a state where the discharge pipe 13 is communicated and connected to a water supply pipe 10 to the demand side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a pump which is configured so that water is sucked from a water main pipe through a suction pipe by a pump and then discharged in a pressurized state to a water supply pipe to a demand side. The present invention relates to a pressurized water supply apparatus and an operation method thereof, and particularly to a pump and a pressurized water supply apparatus that prevents water from staying near the pump for a long time and an operation method thereof.

[0002]

2. Description of the Related Art In order to effectively utilize the water pressure in a water main, water has been directly sucked from the water main through a suction pipe by a pump and then sent to the demand side in a pressurized state. A pressurized water supply device configured to be discharged to a water pipe has already been put into practical use.However, in the conventional pressurized water supply device, water is often supplied to the pump and the vicinity of the pump for a long time. And there is a risk of stagnation.

That is, in a state in which a bypass pipe having a check valve attached thereto is attached and connected in parallel to a pump, a suction (inflow) side pressure as a water pressure in a water main pipe directly supplies water to a demand side. When the pump is sufficiently high, the pump is stopped and water from the water main can be supplied from the suction pipe to the water pipe via the bypass pipe. However, if water supply by the pump is not performed for a long time in this way, water will remain as contaminated water for a long time in the pump and in the vicinity of the pump. When the operation of the pump is restarted due to the decrease, the contaminated water is supplied to the demand side.

[0004] In addition to the case of water supply by a bypass pipe, such a situation is the same when the water is not used for a long time on the demand side and the pump is shut down during that time. Things. Incidentally, when the pump is not operated for a longer period of time, the rust is firmly attached between the fixed part and the movable part of the pump, so that the pump is driven to rotate during the operation of the pump. It cannot be done.

[0005] As a technique relating to the prevention of accumulated water, Japanese Patent Laid-Open Publication No. Hei 8-61246 has been mentioned so far. In this case, the accumulation of water is prevented by alternate operation. .

[0006]

As described above, in the conventional pressurized water supply system directly connected to the water main, if the water pressure in the water main is sufficiently high to supply water directly to the demand side, The pump is put into operation stop state, and the water from the water main is supplied from the suction pipe through the bypass pipe to the water supply pipe side. Therefore, the pump is likely to stay as polluted water over the entire area, and contaminated water may be supplied to the demand side when the operation of the pump is restarted. Such a problem is also observed when water is not used for a long time on the demand side.

[0007] A first object of the present invention is to provide a long-term water supply to a pump and its vicinity even if the water is not used for a long time on the demand side and the pump is in a shutdown state during that time. The purpose is to provide a pressurized water supply device that cannot be retained as contaminated water.

[0008] A second object of the present invention is to operate the pump even when the pump is shut down for a long time due to a high pressure on the suction side and water is supplied to the demand side while bypassing the pump. It is an object of the present invention to provide a method of operating a pressurized water supply apparatus in which water cannot stay as contaminated water for a long time in the vicinity of the pump.

[0009] A third object of the present invention is to reliably detect that water has not been used for a long time on the demand side,
In the meantime, even if the pump is put into an operation stop state, a method of operating a pressurized water supply apparatus in which water cannot be retained as contaminated water for a long time in the vicinity of the pump and the pump is provided.

[0010] A fourth object of the present invention is that the pump is stopped due to a high pressure on the suction side, and that water from the water main can be supplied to the demand side via a bypass pipe. Another object of the present invention is to provide a pump and a method for operating a pressurized water supply apparatus in which water cannot be retained as contaminated water for a long time in the vicinity of the pump when the water is not used for a long time on the demand side.

[0011]

SUMMARY OF THE INVENTION The first object of the present invention is to provide a pump which is connected to a water supply pipe to a demand side and is connected to a discharge pipe. During the operation stop state, the discharge pipe is connected to the discharge pipe every time the operation stop state elapses for a predetermined time so that the pump and water staying in the vicinity of the pump for a long time are discharged to the outside. A control means is provided for keeping the mounted automatic valve open for a certain period of time, and for controlling the pump to be temporarily set in the starting state as the discharge pressure falls below the starting pressure. Achieved by being challenged.

[0012] The second object of the present invention is to stop the operation of the pump due to a high suction side pressure in a state in which a bypass pipe having a check valve is mounted in parallel with the pump. When water from the water main is supplied to the demand side through the suction pipe, the bypass pipe, and the water supply pipe, the water that has been staying for a long time in the vicinity of the pump and the pump is supplied to the demand side. Therefore, each time the pump operation stop state elapses a predetermined time, the initial set value corresponding to the suction side pressure high is reset as being larger than the maximum suction side pressure detection value, and under the constant discharge pressure control. The initial set pump starting pressure or the initial set lower and upper limit discharge target pressures under constant terminal pressure control are the maximum suction side pressure detection value between the discharge side pressure sensor and the suction side pressure sensor at the time of maximum water flow. By resetting the pump to a value higher than the value added, the pump stoppage due to the suction side high pressure is released, and the pump is temporarily stopped in the start-up and operation state. After the water is supplied to the demand side, each of the reset values is achieved by being initialized.

[0013] The third object is that when water is sucked from a water main via a suction pipe by a pump and then discharged as a pressurized state to a water supply pipe to a demand side, the pressure tank is closed. If a state in which water is not used on the demand side is continuously detected by the flow rate sensor provided in the middle of the water supply pipe, which is located on the downstream side, the pump and the vicinity of the pump for a long time Every time the above-mentioned state elapses for a predetermined time, the automatic valve attached to the discharge pipe connected to the water supply pipe is turned on only for a predetermined time so that the water staying over is discharged outside. This is achieved by placing the pump in an open state and temporarily putting the pump in an operating state.

The fourth object of the present invention is to stop the operation of the pump due to a high pressure on the suction side in a state in which a bypass pipe having a check valve is mounted in parallel with the pump. Despite that water from the water main is suction-supplied through the suction pipe, the bypass pipe, and the water supply pipe to the demand side, it is located in the middle of the water supply pipe located downstream of the pressure tank. If the condition that water is not used on the demand side is continuously detected by a flow sensor,
Each time the above-mentioned state elapses for a predetermined time, the pump is attached to a discharge pipe connected to the water supply pipe so that the pump and water remaining in the vicinity of the pump for a long time are discharged to the outside. This is achieved by leaving the automatic valve open for a certain period of time and then temporarily putting the pump in operation.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, before starting a specific description of the present invention, the basic configuration and operation of a conventional pressurized water supply device directly connected to a water main will be briefly described as follows.

That is, FIG. 1 shows a configuration of an example of a pressurized water supply device according to the present invention.
To be more specific, as shown in FIG. 7, while the suction (inflow) side pressure is equal to or higher than the minimum pressure b required for directly supplying water to the demand side, pumping by the pump 4 is unnecessary, and therefore the pump is not required. 4 is an operation stop state, and water from a water main (not shown) is supplied to a demand end 11 through a suction pipe 1, a check valve 3, a bypass pipe 2, a check valve 8, and a water supply pipe 10. Water is to be supplied. The suction side pressure is the pressure a (<
b) In the following, the pump 4 is not allowed to operate in order to prevent a further abnormal decrease in water pressure in the water main. As a result, the pump 4 can be operated only while the suction side pressure is between the pressures b and a. FIG. 6 also shows the relationship between the discharge flow rate (water supply amount) Q, the discharge side pressure H, and the pump rotation speed N. The pressure b is normally set as b = H01. It has become something.

The pump 4 is driven to rotate by the electric motor 5, and its rotation speed depends on the frequency of the AC power from the inverter INV. After all,
The operation of the pump 4 is controlled by an inverter INV. Around the inverter INV,
In addition to a digital operator OP provided with a key switch for displaying operating conditions and for setting parameters for various operations, an earth leakage breaker ELB is arranged for protection from earth leakage. . Further, the suction side pressure is detected by the pressure sensor PS-1 and given as a signal S1, and the discharge side pressure is detected by the pressure sensor PS-2 and given as a signal S3 to the inverter INV. The flow switch provided on the pump discharge side (having the same function as the flow rate sensor and mainly provided for controlling the pump operation) Flow SW also uses water on the demand side. Is detected, and is supplied to the inverter INV as a signal S2. If the water is not used on the demand side or the amount of water is small, the flow switch Flow.
SW is in the ON state.

If water is actually used on the demand side, the discharge side pressure gradually decreases, and eventually, the pressure sensor PS-2 detects that the discharge side pressure drops below the starting pressure HON. For example, the pump 4 is started for the first time, and the water from the water main is supplied to the suction pipe 1, the check valve 3, the gate valve 6-1, the pump 4, the flow switch Flow / SW, the check valve 7, and the gate valve 6.
-2. Water is supplied to the demand end 11 via the water pipe 10. Flow switch F uses less water
low ・ If detected by SW, or if the pressure sensor PS-1 detects that the suction side pressure has become less than or equal to pressure a or more than pressure b due to water supply cut off at the water main, etc. The pump 4 is in an operation stop state.

In FIG. 1, reference numerals PW, 9, and 14 denote an AC power supply (generally a three-phase AC power supply), a pressure tank (having an air reservoir at an upper portion), and a faucet (faucet), respectively. Incidentally, each of the blocks X and Y indicated by a dashed line is a part according to the present invention, which will be described later.

Now, the present invention will be described in detail. As described above, FIG. 1 shows a configuration of an example of a pressurized water supply device according to the present invention. The difference is that each of the blocks X and Y is newly provided, and the inverter INV is provided with microcomputer control software according to the present invention for discharging accumulated water to the outside. Is a point. If the water pressure in the water main is sufficiently high to supply water directly to the demand side, the stagnant water will be supplied to the demand side due to the temporary start and operation of the pump, but no water will be used on the demand side. For this reason, when the pump is put in the operation stop state, the water remaining for a long time in the vicinity of the pump 4 and the pump 4 is discharged to the outside via the block X. As shown in FIG. 1, for the water pipe 10,
A discharge pipe 13 having an automatic valve 12 attached to the other end thereof is connected to each other. However, every time a predetermined time elapses from the operation stop state due to no water usage on the demand side, the automatic valve 12 is closed. Is kept open for a certain period of time, and is controlled so that the pump 4 is temporarily put into the starting state as the discharge pressure falls below the starting pressure. It has been released to.

Here, the microcomputer software as the control means according to the present invention will be described with reference to FIG. First, the case where water is not used on the demand side in the normal state, and therefore, the pump 4 and water staying in the vicinity of the pump 4 for a long time will be described. First, at step 400, the discharge side pressure (water supply pressure) ) Is below the starting pressure HON. In this determination, if water is not used, the discharge side pressure is naturally higher than the starting pressure HON, so that the determination is NO and the process proceeds to step 417. In step 417, the suction side pressure (inflow pressure) is changed to the pressure b
It is determined whether the above is true (when the pressure is equal to or higher than b, the pump 4 is in an operation stop state). However, in this determination, the determination is NO, and the process proceeds to step 418. In step 418, it is determined whether the suction side pressure is equal to or lower than the pressure a.
Is in an operation stop state), the determination is also NO, and the process proceeds to step 419. After all, by the above processing, the suction side pressure becomes the pressure b
The pump operation stop when the pressure is equal to or more than the above and the pump stop when the pressure is equal to or lower than a are eliminated.
19, because there is no water use on the demand side,
The processing relating to the pump operation stop is performed for the first time.

Due to the absence of water, the pump 4
Although the time during which the operation is stopped is separately measured by a software timer, in step 419,
It is determined whether or not a predetermined time T1 or more has elapsed since the pump operation was stopped. Predetermined time T
If one or more have not elapsed, the process returns to step 400. If the predetermined time T1 or more has elapsed, the processing in steps 420 and 421 causes the automatic valve 1
2 is left open and the process returns to step 400. When the automatic valve 12 is in the open state, the stagnant water is released into the atmosphere via the discharge pipe 13, and the discharge-side pressure eventually falls to or below the starting pressure HON with the release of the stagnant water. However, the pump 4 is started for the first time due to the decrease to the starting pressure HON or lower (steps 400 to 405). After the pump 4 is started, the closing process of the automatic valve 12 is performed after a certain period of time in the open state of the automatic valve 12 in Steps 406 and 407. In Step 408, no processing is performed. The end pressure constant control based on the target value F (see FIG. 6) is executed. After the pump 4 is started, a step 41 is executed.
At 0, it is determined whether or not the flow switch Flow • SW is in the OFF state (water use state). , The operation of the pump 4 is stopped in step 412, and the processing is returned to step 400.

As described above, when the water is not used for a long time on the demand side in the normal state, the pump 4 and the water retained near the pump 4 are discharged to the outside every predetermined time T1. What you get. The times T1 and T2 are initially set as appropriate values from the digital operator OP (for example, the time T1 is set to about 4 hours). Thereafter, the values are set as necessary by the digital operator OP as needed. The update can be set from the OP.

Next, a case in which the pump 4 is shut down for a long period of time due to a high suction side pressure (pressure in the water main) will be described. Since the purpose is to supply water to the demand side directly through the bypass pipe 2 using the suction side pressure, usually, the minimum pressure required for such water supply, that is, b = H01 is initially set by the digital operator OP. However, depending on the installation location of the pump 4, the suction side pressure may always exceed H01, and therefore,
In such a case, the pump 6 cannot be operated for a long time.

More specifically, step 417 is executed.
, It is determined that the suction side pressure is equal to or higher than the pressure b, and in step 422, the operation stoppage time of the pump 4 is set to the predetermined time T5.
When it is determined that the above is the case, in step 423, the initial setting value (= b) corresponding to the suction-side pressure high is updated and set to a predetermined value. That is, the initial set value is reset as (the maximum suction side pressure detection value + α) which is larger than the maximum suction side pressure detection value, and the initial setting pump starting pressure HON under the constant discharge pressure control, or The initial lower limit discharge target pressure HO0 and the upper limit discharge target pressure H01 (see FIG. 6) under the constant terminal pressure control are the discharge side pressure sensors at the time of the maximum water amount at the maximum suction side pressure detection value. PS-2 is set to be larger than that obtained by adding the resistance between the suction side pressure sensor PS-1. Thereafter, the flow returns to step 400 to determine whether or not the discharge side pressure is lower than or equal to the starting pressure HON. Since it is updated and set as the value obtained by adding the resistance between the pressure sensor PS-2 and the suction-side pressure sensor PS-1, YES is determined and the process proceeds to step 401. In step 401, it is determined that the suction side pressure is not lower than the pressure a, and the process proceeds to step 402.
The pressure b in step 402 is determined to be NO in step 402 because the pressure b has already been updated to (maximum suction side pressure detection value + α) in step 423. In the subsequent step 403, it is determined that the pump 4 is not in operation, and the pump 4 is started in step 405. Thereafter, the determination is NO in step 406, and in step 408, the pump 4 is operated until the accumulated water is sent to the demand side, and then the pressure b, the starting pressure HON, and the target pressure HO0 · H
01 is to be returned to the initial setting value. Thereafter, steps 409, 410, 411, 413, 4
After sequentially passing through steps 15 and 416, in step 412, the operation of the pump 4 is stopped due to the high pressure on the suction side, and water is supplied by the bypass pipe 2.

As described above, in the pressure control in step 409, until the pressure b, the starting pressure HON, and the target pressures HO0 and H01 return to the initial set values, the target pressure HO0 = H01>
The constant discharge pressure control is adopted (the resistance between the discharge-side pressure sensor PS-2 and the suction-side pressure sensor PS-1 at the time of the maximum suction-side pressure detection value + the maximum water amount). In other words, in the check valve 8, as a result of the pressure on the outlet side being slightly higher than that on the inlet side, the water remaining in the pump 4 and its vicinity can be sent to the demand side by the operation of the pump 4. It is. Incidentally, step 413,
Processes 414 and 412 indicate a process of stopping the operation of the pump 4 due to a decrease in the suction side pressure.

FIG. 3 also shows that even if the pump 4 is shut down for a long time due to a high pressure on the suction side without using water on the demand side, the accumulated water is discharged to the outside. 1 shows the configuration of the main part of FIG. As shown in the figure, a timer T10 for measuring a suction side high pressure state (a state of a pressure b or more), and a case where the pump 4 is put into an operation stop state without using water on the demand side, the operation stop state is set. A timer T11 for measuring time is provided. If the pump 4 is put into an operation stop state without using water on the demand side, terminals 10 and 11 are connected from the inverter INV.
As a result of the output of the ON signal, the timer T11 starts its timing operation. Timer T
If, for example, the time is up 4 hours after the start of the timing operation, the contact T11a is closed,
The automatic valve 12 is kept open via the drive circuit SL from the time when the (slow recovery) contact T11a is closed until the time when the contact is restored after a certain time (for example, about 10 to 15 minutes). is there. When the suction side pressure becomes high, the ON signal is output from the inverter INV to the terminals 8 and 9, so that the timer T10 starts its timing operation. If the timer T10 expires, for example, four hours after the start of the timing operation, the contact T1 in the block Y (see FIG. 1)
0a is closed, but when this is notified to the inverter INV via the input terminal 23, for example, step 423 is executed instead of steps 417 and 422 in FIG. In the same manner as described above, the pump operation stop due to the suction side high pressure is released, and the pump 4 can be started.

Further, in order to simplify the control, the automatic valve 12 is turned on for a predetermined time (for example, 10 to 15) every predetermined time (for example, 4 hours) regardless of the pump system and the pressure condition.
It is also conceivable to forcibly leave it open for only a minute). FIG. 4 shows a main configuration in this case. Each time the timer T12 counts up every predetermined time, its contact T12a is closed.
The automatic valve 12 is kept open via the drive circuit SL from the time when the contact T12a is closed to the time when it is restored after a certain time (for example, about 10 to 15 minutes).

Finally, the case where the accumulated water is discharged by the flow rate sensor provided on the water supply pipe 10 without using the pressure or the timer (T12) will be described. FIG. 5 shows the pressurized water supply apparatus in this case. An example configuration is shown. As shown in the figure, a flow sensor 15 provided on the water pipe 10
Although the presence / absence of water usage on the demand side is more reliably detected, the detection result is input to the input terminal 8 as a signal S4.
Through the inverter INV. As a specific control operation, for example, a step for determining the detection result of the flow rate sensor 15 is added between steps 418 and 419 in FIG. It is sufficient that the processing of (1) is executed. That is, step 4
In 19, when it is determined that the predetermined time T1 or more has elapsed from the time when the pump operation was stopped, the automatic valve 12 has been opened by the processing of step 420 and subsequent steps. If water use has been detected, the process has returned to step 400.

[0030]

As described above, according to each of the first to fifth aspects, the following effects can be obtained. In the case where the water is not used for a long time on the demand side and the pump is put into a shutdown state during that time, the water can be retained as polluted water for a long time in the pump and the vicinity of the pump. No pressurized water supply is obtained.

The pump and its pump are operated even if the pump is shut down for a long time due to the high pressure on the suction side and water is supplied to the demand side while bypassing the pump. A method of operating a pressurized water supply apparatus in which water cannot stay as contaminated water for a long time in the vicinity is obtained.

The demand side reliably detects that the water has not been used for a long period of time, and in the meantime, even if the pump is in an operation stop state, the water is kept near the pump and the pump. A method of operating a pressurized water supply device that cannot be retained as contaminated water for a long period of time is obtained.

Claim 5: The pump is shut down due to a high pressure on the suction side, and the water from the water main is supplied to the demand side via the bypass pipe. When the water has not been used for a long period of time, a method of operating a pressurized water supply device in which water cannot be retained as contaminated water for a long period of time in the vicinity of the pump and the pump is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an example of a pressurized water supply device according to the present invention.

FIG. 2 is a diagram showing a processing flow in an example of microcomputer software as control means according to the present invention;

FIG. 3 is a diagram for discharging accumulated water to the outside even when the pump is shut down for a long time due to a high pressure on the suction side without using water on the demand side. Diagram showing main configuration

FIG. 4 is a diagram showing a main part configuration in a case where an automatic valve is forcibly kept open for a predetermined time at predetermined time intervals regardless of a pump system and pressure conditions.

FIG. 5 is a diagram showing a configuration of an example of a pressurized water supply device in a case where accumulated water is discharged by a flow rate sensor provided on a water supply pipe.

FIG. 6 is a diagram showing a relationship among a discharge flow rate (water supply amount), a discharge side pressure, and a pump rotation speed among these three components.

FIG. 7 is a diagram showing a water supply range by a pump operation, a bypass water supply range, and a pump inoperable range due to an abnormal decrease in a suction side pressure, according to a suction side pressure.

[Explanation of reference numerals] 1 ... suction pipe, 2 ... bypass pipe, 3, 8 ... check valve, 4 ...
Pump, 5: electric motor, 9: pressure tank, 10: water pipe,
12 ... automatic valve, 13 ... discharge pipe, 15 ... flow sensor, IN
V: Inverter, OP: Digital operator, PS-
1, PS-2: Pressure sensor, Flow ・ SW: Flow switch

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F04B 49/00 F04B 49/10 311 49/10 311 49/02 311 F term (reference) 3H020 AA01 BA00 BA01 BA02 BA03 BA05 BA11 CA00 CA01 CA03 CA04 DA01 DA04 DA13 DA17 DA28 EA03 EA09 EA12 EA16 3H045 AA09 AA12 AA23 BA03 BA07 CA02 CA03 CA06 CA25 CA29 DA02 DA07 DA18 EA13 EA14 EA26 EA38

Claims (5)

[Claims] 1. A bypass pipe having a check valve attached thereto is connected in parallel to a pump, and a discharge pipe is connected to a water supply pipe to a demand side. A pressurized water supply device that is configured so that water is sucked from a water main via a suction pipe and then discharged to the water supply pipe in a pressurized state, and there is no use of water on the demand side. Due to the above, while the pump is in an operation stop state, water that has been staying for a long time in the vicinity of the pump and the pump is discharged to the outside,
Each time the operation stop state elapses a predetermined time, the automatic valve attached to the discharge pipe is kept open for a certain period of time, and the pump is driven by the discharge pressure falling below the starting pressure. A pressurized water supply device having a control means for temporarily controlling the water supply to be in a starting state. 2. The pressurized water supply device according to claim 1, further comprising means for arbitrarily setting each of the predetermined time and the predetermined time from outside. 3. The pump is shut down due to a suction-side high pressure in a state where a bypass pipe to which a check valve is attached is attached and connected to the pump in parallel.
When water from the water main is supplied to the demand side through the suction pipe, the bypass pipe, and the water supply pipe, the water that has been staying for a long time in the vicinity of the pump and the pump is supplied to the demand side. Therefore, each time the pump operation stop state elapses a predetermined time, the initial set value corresponding to the suction side pressure high is reset as being larger than the maximum suction side pressure detection value, and under the constant discharge pressure control. The initial set pump starting pressure or the initial set lower and upper limit discharge target pressures under constant terminal pressure control are the maximum suction side pressure detection value between the discharge side pressure sensor and the suction side pressure sensor at the time of maximum water flow. By resetting the pump to a value higher than the one with the resistance added, the operation stop of the pump due to the suction side high pressure is released and the pump is temporarily put in the start-up and operation states, causing a delay. After the water is water in the demand side, the value each supply pressure water system operating method to be initialized according to the reset. 4. When water is sucked from a water main through a suction pipe by a pump and discharged to a water supply pipe to a demand side in a pressurized state, the water is located downstream of the pressure tank. In the case where a state in which water is not used on the demand side is continuously detected by a flow rate sensor provided in the middle of the water supply pipe, the pump stays near the pump for a long time. Every time a predetermined time elapses, the automatic valve attached to the discharge pipe connected to the water supply pipe is kept open for a certain period of time so that the water flowing out is discharged to the outside. And a method of operating a pressurized water supply device in which a pump is temporarily put into an operating state. 5. The pump is shut down due to a suction-side high pressure in a state in which a bypass pipe having a check valve is attached to and connected in parallel with the pump.
Despite that water from the water main is suction-supplied through the suction pipe, the bypass pipe, and the water supply pipe to the demand side, it is located in the middle of the water supply pipe located downstream of the pressure tank. When a state in which water is not used on the demand side is continuously detected by the flow rate sensor, the pump and water remaining for a long time in the vicinity of the pump are discharged to the outside. Every time the above-mentioned state elapses a predetermined time, the automatic valve attached to the discharge pipe connected to the above-mentioned water pipe is kept open for a certain period of time, and the pump is temporarily operated. A method of operating a pressurized water supply device in a state.