JP2000034983A - Water supply pump device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To perform optimal water supply control depending on whether or not a water main pressure as a water pressure on a pump suction side exceeds a suction target pressure. SOLUTION: When a suction side water pressure detected by a pressure sensor 5 provided on a pump 1 suction side exceeds a preset suction target pressure, the water pressure on the pump 1 discharge side is set to a preset target pressure. While the pump 7 is controlled to increase in speed by the controller 7 via the inverter 3 so as to match the pressure,
Conversely, when the suction-side water pressure is equal to or lower than the preset suction target pressure, the pump 1 is decelerated by the controller 7 so as to control the suction-side water pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water supply pump control system of a type in which water is supplied using a pump driven at a variable speed by an electric motor whose speed is controlled by an inverter. The present invention relates to a water supply pump control device suitable for a system.

[0002]

2. Description of the Related Art A pump is required as a water supply system in an apartment house or various buildings. In such a case, the demand for water supply varies greatly depending on the date and time, such as daytime and nighttime, or work and holidays. . For example, FIG. 10 shows a change in water supply demand in a certain water supply system in one day, and as is apparent from this, the water supply demand changes by several tens of times.

Therefore, in such a case, a pump driven at a variable speed by an electric motor whose speed is controlled by an inverter is conventionally used. At this time, the rating of a water supply device including the inverter, the electric motor, and the pump is as follows. The water supply load is selected according to the demand during the maximum time, and the inverter is used to reduce the number of revolutions of the motor from the rated value as the demand decreases, so that water supply that meets the demand can be performed. I was

That is, as shown in FIG. 11, a water supply amount Q of a pump changes with its rotation speed N as a parameter.
In the conventional water supply apparatus described above, so that the water supply amount QR of the rated rotational speed N _R is the maximum water demand Q _M, in other words, to select the rated power of the electric motor such that Q _R = Q _M The engine is always operated in the range below the rated speed NR.

[0005]

In the prior art, no consideration is given to the fact that the water supply system is operated at less than the maximum water supply load in many hours, and there is a problem in the efficient operation of the water supply system. was there. That is, in the prior art, for example, as shown in FIG. 10, in the case of a water supply system in which the water supply demand greatly fluctuates, the rating of the water supply device is shown in the demand during the time when the water supply load is maximum, for example, as shown in FIG. Water supply
(= Maximum water demand Q _M ).

However, as is apparent from FIG. 10, in many time zones, the amount of water used is much smaller, and the average water supply is considerably lower than the water supply a. Assuming that the capacity of the motor is selected according to the time when the demand for water supply is at its maximum,
In many situations, the motors and pumps are operated out of the point of maximum efficiency, which results in wasteful energy consumption and higher equipment costs. is there.

An object of the present invention is to provide a water supply pump control device capable of operating efficiently in many time zones and sufficiently suppressing wasteful energy consumption and increase in equipment costs.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inverter control means for setting the output frequency of an inverter higher than the rating of a motor, and a timing means for measuring a time when the output frequency of the inverter is set higher than the rating of the motor. This is achieved by returning the output of the inverter to the rated value when the measured time exceeds a predetermined time.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a water supply pump control device according to the present invention will be described in detail with reference to the illustrated embodiments.
FIG. 1 shows an embodiment of the present invention, in which 1 is a pump, 2 is a motor for driving the pump 1, and 3 is a motor for converting the input three-phase power into three-phase AC power of an arbitrary frequency to enable the motor 2. Inverter for shifting drive control, 4 is a pressure sensor for measuring the pressure on the pump discharge side, 5 is a pressure sensor for measuring the pressure on the pump suction side, 6 is a control device for controlling water supply operation, 7 is a controller, 8 is a temperature sensor for detecting the temperature of the motor 1, and 9 is a warning device (a lamp, a buzzer, etc.) for notifying that the motor 2 has reached an estimated useful life (lifetime).

The output of the motor 2 at the rated speed N _R is
The maximum water supply demand Q _M required for this water supply device, for example, b which is 70% of the water supply amount shown in FIG.
The water demand as the rated water amount _{Q R (= 0.7 × Q M} ) indicated by this one which is selected to correspond to the rated water amount Q _R, is variable speed controlled by an inverter 3, the pump 1 It is driven to rotate, pressurizes water supplied from a suction side pipe 13 connected to a water main 12, and discharges a pipe 14
The water is supplied to the water supply line 15 via the.

The inverter 3 is controlled by a rotation speed (frequency) signal N supplied from the controller 7, and supplies AC power having a frequency corresponding to the rotation speed N to the electric motor 2 to perform a variable speed operation.

The pressure sensor 4 functions to detect the pressure of water in the pipe 14 on the discharge side and to input the discharge pressure Hout to the controller 7, and the pressure sensor 5 functions to input the pipe 1 on the suction side.
The function of detecting the pressure of the water in 3 and inputting the inflow (suction) pressure Hin to the controller 7 is as follows. On the other hand, the temperature sensor 8
Functions to detect the temperature of the electric motor 1 and input the detected temperature to the controller 7.

FIG. 2 is a detailed view of the controller 7, wherein 71 is a central processing unit (CPU), 72 is a storage device (SRAM) having a backup power supply, and 73 is an input / output circuit (I
/ O), and the signals sent from the pressure sensors 4 and 5 are
Via the input / output circuit 73, the central processing unit 71 takes in the data representing the discharge pressure Hout and the inflow pressure Hin, and the signal supplied from the temperature sensor 8 is data representing the temperature t of the electric motor 1. Central processing unit 71
It is taken in.

The central processing unit 71 performs arithmetic processing based on these various data, outputs a rotation speed signal N to control the number of rotations of the electric motor 2, and measures and accumulates (accumulates) the operation time. Processing such as addition). And
Data representing the accumulated operation time is stored in a storage device 72 having a backup power supply so that the data does not disappear even when the power supply of the system is turned off. Further, when the central processing unit 71 determines that the accumulated operating time has reached the estimated life, the central processing unit 71 also executes a process of issuing a warning by the warning device 9.

Next, the operation of this embodiment will be described with reference to FIGS.
This will be described with reference to the flowchart shown in FIG. First, in FIG. 3, in a main process 30, after the power is turned on, the pump discharge side pressure Hout is lower than the starting pressure H3, and the pump inflow pressure H
If in exceeds the suction target pressure SH0, the discharge side control 40 is executed, and the pump inflow pressure Hin becomes the suction target pressure S0.
If H0 or less, the suction side control 50 is executed. After the power is turned on, a sequential time calculation process 90 is executed.

FIG. 4 shows the details of the discharge-side control 40. In this processing, the discharge-side pressure Hout is checked, and the discharge-side pressure Hout is obtained.
If it is equal to or less than 0, the speed increase control 60 is executed, and if the discharge side pressure Hout exceeds the discharge target pressure H0, the deceleration control 70 is executed.

FIG. 5 shows the details of the suction side control 50. This processing is performed when the pump inflow pressure Hin exceeds the pump emergency stop pressure Hsp, and the pump inflow pressure Hin becomes equal to the suction target pressure S.
If it exceeds H0, the speed increase control 60 is executed, and if the pump inflow pressure Hin is equal to or lower than the suction target pressure SH0, the deceleration control 70 is executed. However, when the pump inflow pressure Hin is extremely small and is equal to or lower than the pump emergency stop pressure Hsp, the pump 1 is emergency stopped so as to prevent an abnormal decrease in the water pressure in the water main 12. .

FIG. 6 shows the details of the speed increasing control 60. In this process, if the motor 2 and the pump 1 are stopped, a process for soft-starting from the minimum rotational speed is executed. A process for increasing the number of rotations of one is executed. At this time, as long as the discharge side pressure Hout is smaller than the discharge target pressure H0, the central processing unit 71 sets the rotation speed of the electric motor 2 to a value higher than the rated rotation speed N _R , for example, as shown in FIG. The frequency signal N is controlled so as to reach the rotation speed N _H, and a water supply capacity exceeding the rating is exhibited.
Although the motor 1 having the rated rotation speed N _R is used, it is possible to sufficiently cope with the time zone in which the maximum water supply demand Q _M shown in FIG. 10 is required.

FIG. 7 shows the details of the deceleration control 70. In this processing, if the flow rate of the discharged water is small and the flow switch Fs (not shown in FIG. 1) is in the ON state, the pump stop processing is executed. For example, processing for reducing the number of rotations of the electric motor 2 and the pump 1 is executed. FIG. 8 shows the details of the pump stop process. In this process, after the operation within the pump stop determination speed Ns is continued for about 2 minutes, the operation speed is reduced to Ns.
After the pressure is raised to t so that water is sufficiently stored in the pressure tank, a process of soft-stopping the electric motor 2 and the pump 1 is executed.

[0020] Figure 9 is a detail of the time calculation process 90, the process monitors the rotational speed signal N at all times, each time the motor 2 is ready to be operated beyond the rated speed N _R, each time Then, measurement of the operation time (elapsed time) T from the time when the rated rotation speed N _R is exceeded is started. Then, at this time, the temperature t of the electric motor 2 detected by the temperature sensor 8 is compared with a preset allowable maximum temperature tmax, and a coefficient n (n = 1, 1) added to the operation time T according to the deviation. 2,4,8 ...
...) · ΔT is changed to calculate an integrated time T _C (≧ T).

Here, the maximum allowable temperature tmax is set according to the insulation specification of the motor 2. For example, in the case of a motor using an E type insulating material, the maximum allowable temperature tmax is tmax = 120 ° C. It is set as. When the temperature t of the electric motor 2 becomes equal to or higher than the permissible maximum temperature tmax + 30 ° C., the electric motor 2 is immediately stopped and the operation of the pump 1 is stopped, so that an abnormal temperature rise due to the overload operation is prevented. Is to be prevented.

On the other hand, in parallel with this, the central processing unit 71 constantly monitors the accumulated time T _C, and when the accumulated time T _C reaches a preset reference time T _S (T _C ≧ T _S ), this is also set in advance. Until the set predetermined time T ₀ elapses, the frequency signal N is output so that the rotation speed of the electric motor 2 becomes equal to or lower than the rated rotation speed N _R irrespective of the water supply amount requested at that time. Here, the reference time T _S is the electric motor 2
May be set so as to give a sufficient time for the temperature t to drop below the allowable maximum temperature tmax.

Next, every time the integrated time T _C is obtained, the central processing unit 71 calculates the accumulated time TA stored in the storage device 72 up to that time, that is, the integrated time accumulated up to that time. By adding to the time T _C , a new accumulated time T A is obtained and monitored, and this is
When the time reaches the durable limit of, for example, 2 × 10 ⁴ hours, a signal is sent to the warning device 9 and a process of notifying the signal is executed.

[0024] Therefore, according to this embodiment, despite using the electric motor 2 to 70% of the rated required rotational speed (output), fully corresponds to the maximum water supply demand Q _M, the request Can be ensured, and as a result, operation close to the rated output can be obtained on average, and the efficiency is greatly improved, so that the power consumption is reduced and the facility cost is sufficiently reduced. be able to.

If, for some reason, the time during which the electric motor 2 is operated beyond the rated speed is extended for some reason, the electric motor 2 is operated in rated operation according to the elapsed time and the temperature of the electric motor 2. Therefore, the occurrence of an abnormality in the electric motor 2 can be prevented beforehand, and even at this time, the water supply operation is not stopped but the water supply operation is continued although the water supply amount is reduced. Therefore, the reliability can be sufficiently maintained.

Further, according to this embodiment, an alarm is issued by accumulating the time during which the electric motor 2 has been operated at the rated speed or higher. At this time, the accumulated time is the length of time during which the electric motor 2 is overloaded.
Therefore, since it is possible to estimate whether or not the electric motor 2 has reached the service limit (lifetime) based on the length of the time, predetermined maintenance can be performed by the above-mentioned alarm, and the device is broken down and the water supply is stopped. Such a situation can be prevented from occurring, and the reliability can be further improved.

In the above embodiment, the case where the present invention is applied to a water supply device has been described. However, the present invention can also be applied to a compressor and a blower using an electric motor.

[0028]

According to the present invention, since the speed is increased by increasing the rotation speed by the inverter, the rated output corresponding to the water supply amount less than the maximum water supply amount (about 70% of the maximum water amount) is obtained. Since an electric motor can be selected, equipment costs can be sufficiently reduced, and the capacity of power supply equipment and the like can be reduced.

Further, according to the present invention, since the operation in the maximum efficiency state can be obtained for a long time on average, the efficiency is greatly improved and energy saving is obtained, so that there is an effect that the running cost can be reduced.

Further, according to the present invention, a motor having a rated output smaller than the required output is used, and the maximum demand is met by the rotation speed higher than the rated speed.
If the operation time at this time becomes longer, there is a possibility that an abnormality may occur. However, in the present invention, the operation time exceeding the rating is integrated, and when the integrated time reaches a predetermined value, the operation is returned to the rated operation state or less. Therefore, there is no fear of occurrence of abnormality, and sufficient reliability can be obtained.

Further, according to the present invention, when the temperature of the motor itself exceeds the allowable maximum temperature, not only can the pump be put into operation stop state, but also it is estimated that the motor has reached the service limit (life). As a result, a warning can be given beforehand, whereby the maintenance time can be known, and the stoppage of the operation can be reliably avoided by appropriate measures, so that the reliability can be further improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a feedwater pump control device according to the present invention.

FIG. 2 is an explanatory diagram of a controller according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a main process in one embodiment of the present invention.

FIG. 4 is a flowchart showing discharge-side control in one embodiment of the present invention.

FIG. 5 is a flowchart showing suction-side control in one embodiment of the present invention.

FIG. 6 is a flowchart showing speed increasing control in one embodiment of the present invention.

FIG. 7 is a flowchart showing deceleration control in one embodiment of the present invention.

FIG. 8 is a flowchart showing pump stop control in one embodiment of the present invention.

FIG. 9 is a flowchart showing a time calculation process in one embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a change in water supply demand.

FIG. 11 is a characteristic curve diagram of a pump.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pump, 2 ... Electric motor, 3 ... Inverter, 4, 5 ... Pressure sensor, 6 ... Control device, 7 ... Controller, 8 ... Temperature sensor, 9 ... Warning device, 12 ... Water main line, 13 ... Piping on suction side , 14: piping on the discharge side, 15: water supply line.

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[Procedure amendment]

[Submission Date] August 19, 1999 (1999.8.1)
9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Water supply pump device

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water supply pump device of a type in which water is supplied to a demand side by use of a pump driven at a variable speed by an electric motor whose speed is controlled by an inverter, and in particular, is directly connected to a water main. The present invention relates to a water supply pump device suitable for use as a state.

[0002]

2. Description of the Related Art Conventionally, a water supply pump for water supply is directly connected to a water main from the viewpoint of preventing water contamination due to backflow and preventing erroneous measurement of a water meter (water meter) due to a water hammer. Was regulated. For this reason, as described in, for example, JP-A-59-188096, water is once injected from a water main into a water receiving tank, and the water in the water receiving tank is pumped up by a water supply pump and sent to each customer. That is the current situation.

Recently, while utilizing the pressure of the water main,
In order to eliminate unsanitary receiving tanks, studies have been started on a method of supplying water by directly connecting a water supply pump to a water main. It is considered that a water supply device using an inverter is effective for this in the following points.

1) If the pressure of the water main becomes high, the operating speed of the pump can be reduced in order to keep the pressure on the pump discharge side constant, and power is saved. 2) Since the pump can be started at a low speed when it is started, the pressure of the water main is not instantaneously reduced. 3) When the pressure of the water main decreases, the water supply to the customer can be adjusted by reducing the pump operation speed by the inverter.

[0005]

When the water supply pump is used directly connected to the water main, the above-mentioned advantages can be obtained. However, it is the residents of high-rise buildings of three or more floors that use a water supply system with a pump directly connected to the water main, and ordinary consumers directly use the pressure of the water main without having a pump facility. Water is supplied from the water supply terminal.
For this reason, if a customer having a pump facility uses a large amount of water in the water main when the water main pressure is reduced due to a disaster or the like, water may not be supplied to general consumers. Since such inequality is not preferable, it is necessary to provide a water supply device directly connected to a water main to be provided with a function capable of achieving horizontal water supply and the like. As a water supply device for directly connecting a main pipe for horizontal supply or the like, for example, JP-A-2-28
There is a technique described in US Pat. In this prior art, in addition to a first control system for turning on and off a pump in accordance with the pressure in a pressure tank, a second control system for adjusting a pressure regulating valve provided on a pump outlet side in accordance with the pressure of a water main. Is established,
When the main pipe pressure is reduced, a large amount of water in the main pipe is prevented from being sucked into the pump by the function of the second control system.

According to the above-mentioned prior art, it is possible to achieve horizontal feeding when the main pipe pressure is reduced. However, in this conventional technique, since both the first control system and the second control system function in parallel, there is a problem that the pump performance is deteriorated and the energy loss is increased. That is, when the pressure in the water main decreases, the pressure in the pressure tank decreases due to a decrease in water supply to the pump, and the first control system turns on the pump, while the second control system decreases the main line pressure.
By the control system, the outlet side of the pump is throttled by the pressure regulating valve,
In extreme cases, the pump is forced to shut off. In this case, there is a high possibility that the pump performance is reduced and the pump is damaged, and the energy loss increases.

A first object of the present invention is to provide a water supply main pressure as a water pressure on the pump suction side as well as not only energy saving operation can be achieved without deteriorating the pump performance, but also a horizontal supply can be easily realized. It is an object of the present invention to provide a water supply pump device for direct connection to a water main, which can perform optimum water supply control depending on whether the pressure exceeds a suction target pressure.

A second object of the present invention is to provide a water supply main pressure as a water pressure on the pump suction side as well as not only energy saving operation can be achieved without deteriorating the pump performance, but also a horizontal supply can be easily realized. The water supply can be optimally controlled depending on whether the pressure exceeds the suction-side pump stop pressure (pump emergency stop pressure) and whether the water main pressure exceeds the suction target pressure. To provide a water supply pump device for direct pipe connection. A third object of the present invention is to
The horizontal supply can be easily realized, and the pump performance is not degraded and energy saving operation can be achieved. In addition, when the water main pressure as the water pressure on the pump suction side exceeds the suction target pressure, or when the suction Optimal water supply control can be performed depending on the case where the pressure exceeds the pump side stop pressure (pump emergency stop pressure) and is equal to or lower than the suction target pressure or the case where the pressure is equal to or lower than the suction side pump stop pressure.
To provide a water supply pump device for direct connection to water mains. A fourth object of the present invention is to provide a horizontal feeder or the like that can be easily realized, and not only to perform energy-saving operation without deterioration of pump performance, but also to perform maintenance work on the pump while the pump is stopped. Is done,
An object of the present invention is to provide a water supply pump device for directly connecting to a water main, which can continuously supply water to a demand side.

[0009]

The first object of the present invention is to control the speed increase so that the water pressure on the pump discharge side matches the target pressure when the hydraulic pressure on the pump suction side exceeds the target suction pressure. When the water pressure on the pump suction side is equal to or lower than the suction target pressure, this can be achieved by providing a control means for performing deceleration control to control the water pressure on the pump suction side. The second object is that when the water pressure on the pump suction side exceeds the suction side pump stop pressure and exceeds the suction target pressure,
If the water pressure on the pump suction side exceeds the above-mentioned pump stop pressure and is equal to or lower than the suction target pressure, the water pressure on the pump suction side is controlled. This is achieved by providing control means for performing deceleration control as much as possible and controlling to stop the pump when the water pressure on the pump suction side is equal to or lower than the suction side pump stop pressure. The third object is to control the discharge side so that the water pressure on the pump discharge side matches the target pressure when the water pressure on the pump suction side exceeds the suction target pressure. Exceeding the stop pressure, and when the pressure is equal to or less than the suction target pressure, performs suction side control to control the water pressure on the pump suction side, and when the water pressure on the pump suction side is equal to or less than the suction side pump stop pressure, This is achieved by providing control means for controlling the pump to stop. The fourth object is to combine a suction pipe for sucking water from a water main pipe, first and second pipes branched from the suction pipe, and water from each of the first and second pipes. A water supply pipe for supplying to the demand side, a pump provided in the first pipe, and a suction side of the pump,
A first gate valve provided in the first pipe, a second gate valve provided on the discharge side of the pump, provided in the first pipe, and provided in the first and second pipes, respectively. This is achieved by providing a check valve.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a water supply pump device according to the present invention will be described in detail with reference to the illustrated embodiments. FIG.
Is an embodiment of the present invention, wherein 1 is a pump, 2 is a motor for driving the pump 1, and 3 is a variable-speed driving of the motor 2 by converting input three-phase power into three-phase AC power of an arbitrary frequency. Inverter for controlling, 4 is a pressure sensor for measuring the pressure on the pump discharge side, 5 is a pressure sensor for measuring the pressure on the pump suction side, 6 is a control device for controlling water supply operation, 7 is a controller, and 8 is a controller. A temperature sensor for detecting the temperature of the electric motor 1,
Reference numeral 9 denotes a warning device (a lamp, a buzzer, and the like) for notifying that the electric motor 2 has reached an estimated useful life (lifetime).

The output of the motor 2 at the rated rotation speed N _R is as follows:
The maximum water supply demand Q _M required for this water supply device, for example, b which is 70% of the water supply amount shown in FIG.
The water demand as the rated water amount _{Q R (= 0.7 × Q M} ) indicated by this one which is selected to correspond to the rated water amount Q _R, is variable speed controlled by an inverter 3, the pump 1 The water supplied from the suction-side first pipe 13 connected to the water main pipe 12 is pressurized by rotating and is supplied to the water supply pipe 15 via the discharge-side pipe 14. .

The inverter 3 is controlled by a rotation speed (frequency) signal N supplied from the controller 7, and supplies AC power of a frequency corresponding to the rotation speed (frequency) to the electric motor 2 to perform a variable speed operation.

The pressure sensor 4 functions to detect the pressure of water in the pipe 14 on the discharge side, and to input the discharge pressure Hout to the controller 7. The pressure sensor 5 operates in the first pipe 13 on the suction side. Detects the pressure of water at the inflow (suction) pressure Hin
To the controller 7. On the other hand, the temperature sensor 8 functions to detect the temperature of the electric motor 1 and input the detected temperature to the controller 7. In addition, in FIG.
Reference numeral 0 denotes a check valve, reference numerals 17 and 19 denote gate valves, and reference numeral 21 denotes a second pipe on the suction side.

FIG. 2 is a detailed view of the controller 7, wherein 71 is a central processing unit (CPU), 72 is a storage device (SRAM) having a backup power supply, and 73 is an input / output circuit (I
/ O), and the signals sent from the pressure sensors 4 and 5 are
Via the input / output circuit 73, the central processing unit 71 takes in the data representing the discharge pressure Hout and the inflow pressure Hin, and the signal supplied from the temperature sensor 8 is data representing the temperature t of the electric motor 1. Central processing unit 71
It is taken in.

The central processing unit 71 performs arithmetic processing based on these various data, outputs a rotation speed signal N to control the number of rotations of the electric motor 2, and measures and accumulates (accumulates) the operation time. Processing such as addition). And
Data representing the accumulated operation time is stored in a storage device 72 having a backup power supply so that the data does not disappear even when the power supply of the system is turned off. Further, when the central processing unit 71 determines that the accumulated operating time has reached the estimated life, the central processing unit 71 also executes a process of issuing a warning by the warning device 9.

Next, the operation of this embodiment will be described with reference to FIGS.
This will be described with reference to the flowchart shown in FIG. First, in FIG. 3, in a main process 30, after the power is turned on, the pump discharge side pressure Hout is lower than the starting pressure H3, and the pump inflow pressure H
If in exceeds the suction target pressure SH0, the discharge side control 40 is executed, and the pump inflow pressure Hin becomes the suction target pressure S0.
If H0 or less, the suction side control 50 is executed. After the power is turned on, a sequential time calculation process 90 is executed.

FIG. 4 shows the details of the discharge-side control 40. In this process, the discharge-side pressure Hout is checked, and the discharge-side pressure Hout is obtained.
If it is equal to or less than 0, the speed increase control 60 is executed, and if the discharge side pressure Hout exceeds the discharge target pressure H0, the deceleration control 70 is executed.

FIG. 5 shows the details of the suction side control 50. This processing is performed when the pump inflow pressure Hin exceeds the pump emergency stop pressure Hsp, and the pump inflow pressure Hin is reduced to the suction target pressure Ssp.
If it exceeds H0, the speed increase control 60 is executed, and if the pump inflow pressure Hin is equal to or lower than the suction target pressure SH0, the deceleration control 70 is executed. However, when the pump inflow pressure Hin is extremely small and is equal to or lower than the pump emergency stop pressure Hsp, the pump 1 is emergency stopped so as to prevent an abnormal decrease in the water pressure in the water main 12. .

FIG. 6 shows the details of the speed increasing control 60. In this process, if the motor 2 and the pump 1 are stopped, a process for soft-starting from the minimum rotation speed is executed. A process for increasing the number of rotations of one is executed. At this time, as long as the discharge side pressure Hout is smaller than the discharge target pressure H0, the central processing unit 71 sets the rotation speed of the electric motor 2 to a value higher than the rated rotation speed N _R , for example, as shown in FIG. The frequency signal N is controlled so as to reach the rotation speed N _H, and a water supply capacity exceeding the rating is exhibited.
Although the motor 1 having the rated rotation speed N _R is used, it is possible to sufficiently cope with the time zone in which the maximum water supply demand Q _M shown in FIG. 10 is required.

FIG. 7 shows the details of the deceleration control 70. In this processing, if the amount of discharged water is small and the flow switch Fs (not shown in FIG. 1) is in the ON state, the pump stop processing is executed. For example, processing for reducing the number of rotations of the electric motor 2 and the pump 1 is executed. FIG. 8 shows the details of the pump stop process. In this process, after the operation within the pump stop determination speed Ns is continued for about 2 minutes, the operation speed is reduced to Ns.
After the pressure is raised to t so that water is sufficiently stored in the pressure tank, a process of soft-stopping the electric motor 2 and the pump 1 is executed.

[0021] Figure 9 is a detail of the time calculation process 90, the process monitors the rotational speed signal N at all times, each time the motor 2 is ready to be operated beyond the rated speed N _R, each time Then, measurement of the operation time (elapsed time) T from the time when the rated rotation speed N _R is exceeded is started. Then, at this time, the temperature t of the electric motor 2 detected by the temperature sensor 8 is compared with a preset allowable maximum temperature tmax, and a coefficient n (n (ΔT) to be added to the operation time T according to the deviation is added. n = 1, 2,
4, 8...), And the integrated time T _C (≧ T) is calculated.

Here, this allowable maximum temperature tmax is set according to the insulation specification of the motor 2. For example, in the case of a motor using an E type insulating material, the allowable maximum temperature tmax is tmax = 120 ° C. It is set as. When the temperature t of the electric motor 2 becomes equal to or higher than the permissible maximum temperature tmax + 30 ° C., the electric motor 2 is immediately stopped and the operation of the pump 1 is stopped, so that an abnormal temperature rise due to the overload operation is prevented. Is to be prevented.

On the other hand, in parallel with this, the central processing unit 71 constantly monitors the accumulated time T _C, and when the accumulated time T _C reaches a preset reference time T _S (T _C ≧ T _S ), this is also set in advance. Until the set predetermined time T ₀ elapses, the frequency signal N is output so that the rotation speed of the electric motor 2 becomes equal to or lower than the rated rotation speed N _R irrespective of the water supply amount requested at that time. Here, the predetermined time T ₀ is the electric motor 2
May be set so as to give a sufficient time for the temperature t to drop below the allowable maximum temperature tmax.

Next, every time the accumulated time T _C is obtained, the central processing unit 71 calculates the accumulated time TA stored in the storage device 72 up to that time, that is, the accumulated time accumulated up to that time. By adding to the time T _C , a new accumulated time T A is obtained and monitored, and this is
When the time reaches the durable limit of, for example, 2 × 10 ⁴ hours, a signal is sent to the warning device 9 and a process of notifying the signal is executed.

[0025] Therefore, according to this embodiment, despite using the electric motor 2 of the rating of 70 percent of the required rotational speed (output), fully corresponds to the maximum water supply demand Q _M, the request Can be ensured, and as a result, operation close to the rated output can be obtained on average, and the efficiency is greatly improved, so that the power consumption is reduced and the facility cost is sufficiently reduced. be able to.

If, for some reason, the time during which the motor 2 has been operating beyond the rated speed has been extended for some reason, the motor 2 is operated at the rated speed in accordance with the elapsed time and the temperature of the motor 2. Therefore, the occurrence of an abnormality in the electric motor 2 can be prevented beforehand, and even at this time, the water supply operation is not stopped but the water supply operation is continued although the water supply amount is reduced. Therefore, the reliability can be sufficiently maintained.

Further, according to this embodiment, an alarm is issued by accumulating the time during which the electric motor 2 is operated at the rated speed or higher. At this time, the accumulated time is the length of time during which the electric motor 2 is overloaded.
Therefore, since it is possible to estimate whether or not the electric motor 2 has reached the service limit (lifetime) based on the length of the time, predetermined maintenance can be performed by the above-mentioned alarm, and the device is broken down and the water supply is stopped. Such a situation can be prevented from occurring, and the reliability can be further improved.

In the above embodiment, the case where the present invention is applied to a water supply device has been described. However, the present invention can also be applied to a compressor and a blower using an electric motor.

[0029]

As described above, according to the first aspect, horizontal feeding can be easily realized, and the pump performance is not degraded and energy saving operation can be achieved. A water supply pump device capable of performing optimum water supply control depending on whether or not the water main pressure as the water pressure exceeds the suction target pressure. In the case of the second aspect, horizontal water supply or the like is easily realized. In addition, not only can the pump performance be degraded, but also energy saving operation can be achieved, and whether the water main pressure as the water pressure on the pump suction side exceeds the suction side pump stop pressure (pump emergency stop pressure), Further, a water supply pump device capable of performing optimum water supply control depending on whether the pressure of the water main line exceeds the suction target pressure is further provided. Are obtained. Moreover, without the pump performance is deteriorated, not only attained energy-saving operation,
If the main water pressure as the water pressure on the pump suction side exceeds the suction target pressure, it exceeds the suction side pump stop pressure (pump emergency stop pressure), and if it is lower than the suction target pressure, it is lower than the suction side pump stop pressure. A water supply pump device capable of performing optimal water supply control according to each case of
Still further, according to the fourth aspect, horizontal feeding can be easily realized, and furthermore, not only energy saving operation can be achieved without deterioration of pump performance, but also maintenance of the pump while the pump is stopped is performed. Water supply pump devices that can continuously supply water to the demand side even when work is performed have been obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a water supply pump device according to the present invention.

FIG. 2 is an explanatory diagram of a controller according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a main process in one embodiment of the present invention.

FIG. 4 is a flowchart showing discharge-side control in one embodiment of the present invention.

FIG. 5 is a flowchart showing suction-side control in one embodiment of the present invention.

FIG. 6 is a flowchart showing speed increasing control in one embodiment of the present invention.

FIG. 7 is a flowchart showing deceleration control in one embodiment of the present invention.

FIG. 8 is a flowchart showing pump stop control in one embodiment of the present invention.

FIG. 9 is a flowchart showing a time calculation process in one embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a change in water supply demand.

FIG. 11 is a characteristic curve diagram of a pump.

[Description of Signs] 1 ... Pump, 2 ... Electric motor, 3 ... Inverter, 4,5 ... Pressure sensor, 6 ... Control device, 7 ... Controller, 8 ... Temperature sensor, 9 ... Warning device, 12 ... Water main line, 13 .., A first pipe on the suction side, 14... A pipe on the discharge side, 15... A water supply pipe, 16, 18, 20... A check valve, 17, 19.
21: second pipe on the suction side.

[Procedure amendment 2]

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FIG.

[Procedure amendment 3]

[Document name to be amended] Drawing

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[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] Fig. 7

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FIG. 7

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Sato 7-1-1, Higashi-Narashino, Narashino-shi, Chiba Inside the Hitachi, Ltd. Narashino Plant (72) Inventor Masao Yoshida 7-1-1, Higashi-Narashino, Narashino-shi, Chiba Narashino Factory, Hitachi, Ltd.

Claims (3)

[Claims] 1. An inverter for generating AC power of a variable frequency, an electric motor whose speed is controlled at a variable speed by the AC power from the inverter, and a pump rotationally driven by the electric motor. A water supply pump device that sucks water from a pipe and supplies water to the demand side in a pressurized state. When the water pressure on the pump suction side exceeds the suction target pressure, the water pressure on the pump discharge side is increased to the target pressure. A water supply pump device comprising a control means for performing speed-up control so that the hydraulic pressure on the pump suction side is equal to or lower than the suction target pressure while controlling deceleration to control the water pressure on the pump suction side. 2. An inverter for generating AC power of a variable frequency, an electric motor whose speed is controlled at a variable speed by the AC power from the inverter, and a pump rotated by the electric motor. A water supply pump device for sucking water from a pipe and supplying water to the demand side in a pressurized state, wherein the water pressure on the pump suction side exceeds the suction side pump stop pressure and exceeds the suction target pressure. If the water pressure on the pump suction side is higher than the suction pump stop pressure and is equal to or lower than the suction target pressure, the water pressure on the pump suction side is increased. A water supply pump device comprising a control means for performing deceleration control so as to control and stopping the pump when the water pressure on the pump suction side is equal to or lower than the suction side pump stop pressure. 3. An inverter for generating AC power of a variable frequency, an electric motor speed-controlled at a variable speed by the AC power from the inverter, and a pump rotated by the electric motor. A water supply pump device that sucks water from a pipe and supplies water to the demand side in a pressurized state. When the water pressure on the pump suction side exceeds the suction target pressure, the water pressure on the pump discharge side is increased to the target pressure. If the water pressure on the pump suction side exceeds the pump stop pressure on the suction side and is equal to or less than the suction target pressure, the suction side control is performed to control the water pressure on the pump suction side. And a control means for controlling the pump to stop when the water pressure on the pump suction side is equal to or lower than the suction side pump stop pressure.