JP2001173586A - Method for operating motor pump and control device used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for operating a motor pump and a control device used therefor in which a water feeding amount per hour is held constant even though pressure applied to the suction port of the pump is changed. SOLUTION: This method for operating the motor pump used in a pump installation in which pressure loss of a pump discharge side piping system is not changed usually includes a pressure sensor 45 for detecting discharge pressure of the pump 62 and a control device 20 for controlling the rotational speed of the motor pump 62 so as to approximate discharge pressure to a desired value based on the signal of the pressure sensor 45. Even though pressure applied to the suction port of the pump 62 is changed, a water feeding amount per hour is held approximately constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a motor pump and a control device used in the method, and more particularly to a technique for maintaining a substantially constant amount of water supply even when the pressure applied to the suction port of the pump changes. .

[0002]

2. Description of the Related Art There is known a water supply apparatus in which a water supply pressure is controlled by using an inverter and a pressure sensor. This type of water supply device is designed so that the supply pressure does not change much even when the amount of water used changes due to opening and closing of the faucet. That is, even if the pressure loss (that is, the valve opening) of the pump discharge side piping system changes every moment, the supply pressure becomes substantially the same by operating the motor pump at a variable speed. By doing so, for example, even if the faucet is opened and closed in the kitchen while using the hot water shower, the intensity (water amount) of the hot water shower does not fluctuate.

[0003] On the other hand, in applications where the pressure loss (ie, valve opening) of the pump discharge side piping system does not change on a daily basis, the motor pump is generally operated at a constant speed with an AC commercial power supply. There are many. This operation method has no problem, for example, when the pressure applied to the suction port of the pump does not change as in a circulating pump, but as a result, the amount of circulating water is constant, but for example, as in a deep well submersible motor pump, Pressure applied to the suction port of the pump due to fluctuations in water level in the well (water depth pressure)
The change in the pump caused some problems.

That is, when the water level is low, the actual head is large, so that the water amount is reduced. On the contrary, when the water level is high, the actual head is small, so that the water amount is increased. As a result, the administrator of the pump equipment has to take time and effort to switch the valve opening every time. Also, if the water level rises while the operation is continued without adjusting the valve, the amount of water will increase, the well flow speed will increase, and problems such as entrapment of sand in pumps and piping systems and well collapse will occur. Could occur.

Further, in a snow melting system using a deep well submersible motor pump, the amount of supplied water changes due to fluctuations in the water level of the well, so that a sufficient water amount for the snow amount can be obtained even when the well water level is low. Larger (higher head) pumps were used. As a result, an excessive amount of water is supplied on a daily basis with respect to the amount of snow, which is extremely inconvenient and uneconomical in terms of water resources and electric energy consumption.

[0006] In a sewage water treatment facility or the like, a submersible pump or the like is often provided in a raw water tank in which the sewage to be treated is stored. However, the amount of water transferred varies depending on the water level of the raw water tank. The system had to be a batch processing system with a tank. In such a water treatment facility, a land pump may be used, for example, in a suction operation. However, similarly to the submersible pump, the amount of water transferred varies depending on the water level of the raw water tank. As described above, the pressure applied to the suction port of the pump changes, and as a result, the amount of water becomes unstable, which often causes inconvenience.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a method of operating a motor pump in which the amount of water per hour is substantially constant even if the pressure applied to the suction port of the pump changes. Another object of the present invention is to provide a control device used for the method.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention is to provide a pump system in which a pressure loss (ie, a valve opening) of a pump discharge side piping system is changed on a daily basis. In a method of operating a motor pump used for a pump facility, a pressure sensor that detects a discharge pressure of the pump, and a control device that controls a rotation speed of the motor pump based on a signal of the pressure sensor so that the discharge pressure approaches a target value. Provided,
An operation method of a motor pump characterized in that a water supply amount per time is substantially constant even when a pressure applied to a suction port of the pump changes.

Further, a second aspect of the present invention relates to a method of operating a deep well submersible motor pump used for pump equipment in which pressure loss (ie, valve opening) of a pump discharge side piping system does not routinely change. A pressure sensor that detects the discharge pressure at the ground part of the pump, and a control device that controls the rotation speed of the motor pump so that the discharge pressure approaches a target value based on the signal of the pressure sensor. This is a method for operating a deep well submersible motor pump in which the amount of water supply per hour is substantially constant.

A third aspect of the present invention relates to a submersible motor pump used in equipment such as water treatment equipment in which the pressure loss (ie, valve opening) of the pump discharge side piping system does not routinely change. In the operation method, a pressure sensor that detects a discharge pressure at the ground portion of the pump, and a control device that controls a rotation speed of the motor pump based on a signal of the pressure sensor so as to approach the discharge pressure to a target value are provided, and the pump is installed. This is an operation method of a submersible motor pump in which the water supply amount per hour is substantially constant even if the water level of the water tank changes.

The use of the above-described first to third modes of operation of the motor pump means that the pump equipment in which the pressure loss (valve opening) of the pump discharge-side piping system does not change on a daily basis is provided with an inverter. By introducing a constant discharge pressure control utilizing a (frequency converter) or the like, the water supply amount can be kept substantially constant irrespective of water level fluctuations and the like.

According to a fourth aspect of the present invention, there is provided an apparatus suitable for carrying out the above-described method.
A case accommodating the frequency converter, power input / output means provided in the case, a pressure sensor, a signal input means of the pressure sensor provided in the case, and mounting means for mounting the case to the pump pipe; , A pump control device including a switching unit for switching a target value of the discharge pressure.

Further, the control device of the present invention is described in FIG.
A signal input means of a pressure sensor is provided in the controller shown in FIG. 5 to FIG. 5, and a signal of the pressure sensor is directly taken into the device. Here, the rotation speed adjustment knob functions as a target pressure adjustment knob for switching the target value of the pump discharge pressure. By using such a control device, the above-described problem can be easily solved without modifying the existing pump and control panel. That is, even if the pressure applied to the suction port of the pump changes, the motor pump can be operated such that the amount of water supply per time becomes substantially constant.

According to a fifth aspect of the present invention, there is provided a pressure sensor for detecting a discharge pressure at a ground portion of a pump in an existing pump facility configured to intermittently operate a commercial well-driven deep well submersible motor pump. And a control device for controlling the rotation speed of the motor pump so as to bring the discharge pressure closer to the target value based on the signal of the pressure sensor, so that even if the water level of the well changes, the amount of water per hour becomes substantially constant. The control device is a frequency converter, a case accommodating the frequency converter, power input / output means provided in the case, a pressure sensor, a signal input means of the pressure sensor provided in the case, The pump equipment includes an attaching means for attaching the case to the pump pipe and a switching means for switching a target value of the discharge pressure.

According to a sixth aspect of the present invention, there is provided a snow melting system configured to intermittently operate a deep well submersible motor pump in accordance with snowfall intensity, wherein a pressure sensor for detecting a discharge pressure of the pump above the ground is provided. Provide a control device that controls the rotation speed of the motor pump so that the discharge pressure approaches the target value based on the signal of the pressure sensor, so that even if the water level of the well changes, the amount of water per hour becomes substantially constant, The control device includes a frequency converter, a case accommodating the frequency converter, power input / output means provided in the case, a pressure sensor, a pressure sensor signal input means provided in the case, and a case. The snow melting system includes a mounting means for mounting to a pump pipe and a switching means for switching a target value of discharge pressure.

According to a seventh aspect of the present invention, there is provided an existing snow melting system configured to intermittently operate a commercial power source driven deep well submersible motor pump in accordance with snowfall intensity.
A pressure sensor for detecting the discharge pressure at the top of the pump,
A control device that controls the rotation speed of the motor pump so that the discharge pressure approaches the target value based on the signal of the pressure sensor is added, so that the water supply amount per hour becomes substantially constant even when the water level of the well changes, The control device includes a frequency converter, a case accommodating the frequency converter, power input / output means provided in the case, a pressure sensor, a pressure sensor signal input means provided in the case, and a case. The snow melting system includes a mounting means for mounting to a pump pipe and a switching means for switching a target value of discharge pressure.

Most of the existing pump equipment using a deep well submersible motor pump performs simple ON-OFF control of a commercial power supply driven pump such as a snow melting system. For this reason, the amount of water supplied by the pump varies depending on the well water level, which often causes the above-described problem. The present invention simply solves the problem of the existing equipment by adding a pressure sensor and a control device.

In a preferred embodiment of the present invention,
A load detecting means typified by a current sensor is provided in the control device, and when the pump runs out of water or cavitation occurs, the output of the control device is stopped by reducing the load, or the A function to communicate the status to the outside is provided. When the control by the above-mentioned pressure sensor is performed,
For example, in the case of a deep well submersible motor pump, if the well water level drops and the pump goes into a drought operation, the pump will be operated at the maximum rotational speed. This is because the pump discharge pressure at the pressure sensor mounting portion becomes substantially zero, and the control device (inverter) continues to output the highest frequency in order to maintain the target pressure.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. First, a control device (controller) used in the present invention will be described with reference to FIGS. FIG. 1 is a side view showing an example of mounting work when using the controller used in the present invention. In FIG. 1, reference numeral 10 denotes a pump unit, and the pump unit 10 has a configuration in which a pump 12 and a motor 13 are provided on a common base 11. The fluid guided from the suction pipe 14 passes through the suction-side gate valve 15 and the pipe 16, is sucked into the pump 12 from the pump suction port 12 a, is pressurized, and is discharged from the pump discharge port 12 b. The discharged fluid further passes through a check valve 17 and a discharge-side gate valve 18 and is guided to a discharge pipe 19.

The embodiment shown in FIG. 1 shows an example in which the number of revolutions of the motor 13 of the pump unit 10 is adjusted to save energy. The controller 20 is made of an aluminum alloy having good heat conductivity. It is attached to the pipe 16 via a pipe mounting bracket 21 constituting a heat radiating means.

A power cable 28 from a control panel (power panel) 22 is connected to an input side cable 24 which is an input means of the controller 20 at a cable connection box 23. An output cable 25, which is an output means of the controller 20, is connected to the motor 13 that drives the pump 12. A frequency converter is housed inside the controller 20, and converts the frequency of the electric power supplied from the power panel.
The frequency converter generates heat during this frequency conversion, and this heat is effectively radiated to the pump handling liquid flowing through the pipe 16 via the pipe mounting bracket 21 and the pipe 16.

FIG. 2 is a view showing details of the apparatus shown in FIG. 1, and FIG. 3 is a sectional view taken along line III-III of FIG. The controller 20 is a frequency converter body (power module)
30, a backup circuit 31 and a control circuit 32 are accommodated in a case 35 including an upper case 33 and a lower case 34. The upper case 33 and the lower case 34
Is made of an aluminum alloy that has excellent heat dissipation and shields radiated noise. Both are fixed by bolts (not shown) via a seal member 36 such as a gasket to maintain airtightness with the outside air.

In the lower case 34 of the controller 20, a pipe mounting bracket 21 constituting a heat radiating means is provided with bolts 37.
And adhered tightly through the contact. The controller 20 is detachably attached to the pipe 16 by a mounting band 38 in a state where the open surface 21a of the pipe attachment bracket 21 is in close contact with the pipe 16. As a result,
Since the heat generated by the frequency converter is preferably radiated to the pump handling liquid, an air-cooling fan or the like used for a general-purpose inverter is not required. In addition, there is no fear of poor cooling due to a fan failure. In this embodiment, the controller 20 is provided with an external input option cable 39.

On the upper part of the upper case 33, there is provided a cap 41 which covers the operation board 40 and secures the inside and outside airtightness. FIG. 4 is a plan view of the operation board 40. The operation board 40 is provided with a frequency adjustment knob 42 for switching the output frequency stepwise. In this embodiment, the frequency adjustment knob 42 is of an eight-stage type,
Here, the knob is No. 8, the motor 13 is driven by the commercial power source, and the knob No. If it is less than 7, the motor is driven via the frequency converter. Knob No. To 7,
When the mode is switched to 6, 5, 4, 3, 2, 1, the output frequency is lowered step by step.

FIG. 5 is a circuit diagram showing the inside of the case 35. As shown in FIG. This circuit includes an input terminal 50 as input means connected to the input cable 24, an output terminal 51 as output means connected to the output cable 25,
It has a frequency converter main body 30, a backup circuit 31, and a control circuit 32.

The backup circuit 31 includes a first switch 56 for opening and closing an input line 55 connecting the input terminal 50 and the frequency converter main body 30, and an output line connecting the frequency converter main body 30 and the output terminal 51. It has a second switch 58 that opens and closes 57. In addition, the backup circuit 31 bypasses the frequency converter body 30 and connects the input line 55 and the output line 57 to each other.
Switch 60. These switches 5
6, 58 and 60 may use a mechanical contactor or a device using a semiconductor device.

On the other hand, the control circuit 32 inputs an operation signal from the frequency adjustment knob 42 and a failure signal from the frequency converter main body 30, and sends an operation command to the frequency converter main body 30 based on these signals. Output the switches 56 and 5
It is configured to output an opening / closing command to 8,60.

Next, the operation of the controller configured as described above will be described. First, in the initial state or after reset, the first and second switches 56 and 58
Is in a closed state, and the third switch 60 is in an open state. In this state, an operation command is output from the control circuit 32 to the frequency converter main body 30 based on the operation signal from the frequency adjustment knob 42, and power is supplied to the frequency converter main body 30 so that the frequency is converted. Is supplied to the motor 13. In this case, the frequency converter main body 30 is devised with an inrush current prevention circuit or the like so that output can be started automatically when power is supplied. Therefore, at the same time as power is supplied to the input means of the controller 20, power of a predetermined frequency is output from the output means.

Here, the frequency converter main body 30 fails for some reason, and a failure signal is output from the frequency converter main body 30. This signal is input to the control circuit 32, and switching to the backup circuit 31 is performed. In this case, the control circuit 32 first outputs an open command to the first switch 56, and the first switch 56 is opened, and the supply of power to the frequency converter main body 30 is cut off. Subsequently, the control circuit 32 outputs an open command to the second switch 58, and the second switch 58 is opened to electrically disconnect the motor and the frequency converter. Then, the control circuit 32 finally outputs a close command to the third switch 60, and when the third switch 60 is closed, the motor is driven by the commercial power supply. Once the input power is turned off while the backup circuit 31 is operating, the switches 56, 58, and 60 return to the initial state.

On the other hand, the frequency adjustment knob is of an eight-stage type. 8 is driven by the commercial power supply, and knob No. If it is less than 7, the motor is driven via the frequency converter. And knob No. Is switched to 7, 6, 5, 4, 3, 2, and 1, the output frequency decreases each time. According to the controller shown in FIGS. 1 to 5, the output is automatically started with the supply of power. As shown in FIG. 1, this type of equipment is used in a pump facility by interrupting a power line of an existing pump. In particular, no initial setting is required, and the capacity of the pump can be easily adjusted simply by switching the step-type output frequency switch. The controller shown in FIGS. 1 to 5 is a water-cooled type energy-saving controller dedicated to a pump, and has the following features as compared with a general-purpose inverter.

1. Installation of an inverter on the machine side control panel side is not always convenient for applying to many pumps because of the following restrictions. It is necessary to secure an inverter installation space in or near the control panel. Modification of the control panel, including the exchange of pump start / stop signals, is required. It is necessary to take measures against noise in the power line from the inverter to the pump (motor). Cable re-pulling may be necessary. On the other hand, the above-mentioned controller eliminates these restrictions by being a machine-side installation type installed on the pump side, and is optimal for energy saving of many pumps. It can be used simply by interrupting the existing power line,
Since the wiring to the pump (motor) is short, noise and surge voltage are less generated. In addition, the start and stop (start and stop) of the pump can be performed by turning on and off the power supply on the control panel side as before the installation, and when the power is turned on, the output is automatically started. Since the main unit is attached to the pump piping, no special installation space is required.

2. Water-cooled outdoor type Inverters, which dislike humidity, dust and high-temperature environments, are limited in installation locations. On the other hand, the above-mentioned controller adopts a water-cooling system using a handling liquid, with the installation location being the surface of the pump pipe. At this time, a completely sealed structure is adopted for the built-in case of the frequency converter to prevent the occurrence of dew condensation in the case. As a result, the present invention can be applied to pumps for a wide range of uses including outdoors. In addition, since an air cooling fan for cooling is not required, it is advantageous in terms of maintenance. The case is made of aluminum alloy,
The cooling conditions are ensured and radiation noise is cut off.

3. Pump-only general-purpose inverters require complicated initial settings, such as selection of drive modes, in order to handle a wide variety of loads (elevators, belt conveyors, blowers, etc.). On the other hand, the above-mentioned controller does not require any initial setting, and the pump performance can be adjusted in eight stages by switching the manual knob, so that energy can be easily and reliably saved.

FIG. 6 shows a conventional snow melting system using a deep well submersible motor pump. A deep well submersible motor pump 62 is installed in the well 61, and the pump discharge port 62a is provided.
Is connected to a delivery pipe 63 for sending water to the ground. The delivery pipe 63 also serves to support the weight of the pump. The delivery pipe 63 is connected to the discharge pipe 16. A control panel 64 is provided on the ground, from which power from a three-phase AC commercial power supply is supplied to the motor pump 62 via a power cable 65. The snowfall sensor 66 is installed outdoors on the ground, and is connected to the control panel 64 by a signal line. When the snowfall sensor 66 detects the presence of snow, electric power (commercial power frequency) is supplied from the control panel 64 to the motor pump 62. The pressure water from the motor pump 62 is, for example,
The buried piping 68 guides the vehicle to a road or the like (a place with snow to be melted). Nozzles 69 are provided in the buried piping 68 at intervals of, for example, several meters, and water jetting from the nozzles 69 melts the surrounding snow. When the snowfall sensor 66 detects the absence of snow, the supply of power from the control panel 64 stops, and the motor pump 62 stops. In this way, well water is automatically supplied only when snow falls, and snow accumulation can be prevented.

There is also a system that uses a timer to switch the ON / OFF interval of the pump depending on the amount of snow. That is, for example, when the snowfall sensor 66 catches heavy snow, the pump is continuously operated, and when the amount of snow is moderate, the ON time is set to be longer (the OFF time is shorter), and the intermittent operation is performed. This is a system that makes intermittent operation shorter. This saves electricity and water. However, in these systems, the amount of water supplied varies depending on the water level of the well, and sometimes the snow cannot be melted or water is used more than necessary.

FIG. 7 shows the operation method and the control device of the present invention introduced into these existing systems. The control device (controller) 20 is fixed to the pipe surface at the well outlet. The power supplied from the power supply is
It is guided into the controller 20 from an input side cable 24 which is an input means of “0”. The output side cable 25 which is the output means of the controller 20 is connected to the deep well submersible motor pump 6.
2 are connected. A frequency converter is housed inside the controller 20, and converts the frequency of the power supplied from the power supply to a predetermined frequency. The frequency converter generates heat during this frequency conversion, and this heat is effectively radiated to the pump handling liquid (water) flowing through the pipe 16 via the pipe mounting bracket 21 constituting the heat radiating means.

As shown in FIG. 3, the controller 20
A frequency converter main body (power module) 30, a backup circuit 31, and a control circuit 32 are housed in a case 35 including an upper case 33 and a lower case 34. The upper case 33 and the lower case 34 are made of an aluminum alloy which is excellent in heat dissipation and shields radiation noise. Both are fixed by bolts (not shown) via a sealing member 36 such as a gasket, and are airtight with outside air. Is kept. The pipe mounting bracket 21 constituting the heat radiating means is fixed to the lower case 34 of the controller 20 in close contact with a bolt 37.

FIG. 8 is a side view showing a state where the controller 20 is attached to the pipe 16. The pipe mounting bracket 21 of the controller 20 is detachably mounted on the pipe 16 by a mounting band 38. As a result, the heat generated by the frequency converter is preferably radiated to the pump handling liquid, so that an air-cooling fan or the like used for a general-purpose inverter is unnecessary. In addition, there is no fear of poor cooling due to a fan failure. The pressure sensor 45 is provided at the well outlet of the pump discharge pipe 16. The signal is sent to the controller 20 via the signal cable 46. The controller 20 compares the pressure detected by the pressure sensor 45 with a preset target pressure and changes the output frequency to operate the motor pump at a variable speed so that the two values become equal.

An operation board 40 is provided above the upper case 33.
A cap 41 is provided to cover (see FIG. 4) and secure airtightness inside and outside. As shown in FIG. 4, the operation board 40 is provided with a target pressure adjustment knob 42 for switching the target pressure in a stepwise manner. In the above description of FIG. 4, reference numeral 42 has been described as a frequency adjustment knob, but in this embodiment, it functions as a target pressure adjustment knob. The target pressure adjustment knob 42 is of an eight-stage type.
FIG. 9 is a diagram showing the relationship between the flow rate and the well outlet pressure. In FIG. 9, a curve a is a QH curve, and a curve b is a resistance curve including an actual head representing a pressure loss of the discharge side piping system. As shown in FIG. 9, when the knob is set to No. 8, for example, the target pressure becomes 0.5 MPa (100% pressure), and when the knob No. is switched to 7, 6, 5, 4, 3, 2, 1 , Target pressures are 95%, 90%, 85%, 80
%, 75%, 71%, and 67%.

In this system, the pressure loss in the pump discharge side piping system does not change on a daily basis. Therefore, by controlling the discharge pressure of the pump to be constant irrespective of the well water level, the amount of water supply is kept substantially constant. That is, a desired water supply amount can be selected by setting the target pressure adjustment knob. Further, the controller 20 can easily realize constant water supply control by being attached to an existing snow melting system and equipment later and using the existing control panel as it is.

FIG. 10 shows an embodiment in which the above-described operation method and control device are used for a submersible motor pump used in a water treatment facility. In this type of pump, since a large amount of foreign matter is mixed in the liquid to be handled, it is difficult to control the flow rate by the constant flow rate valve because the foreign matter is clogged in the constant flow valve. Therefore, when the pump is operated at a constant rotation speed, the amount of water supply changes depending on the water tank water level. For this reason, there is no choice but to use a batch processing type system having a large tank. In this embodiment, this batch processing type system is a constant flow rate type continuous processing system, and each tank is miniaturized.

The sewage stored in the raw water tank 71 is sent to an aeration tank 73 by a sewage submersible motor pump 72. At this time, the raw water tank 71 is
A constant flow of sewage is sent regardless of the water level. The controller 20 is attached to the discharge pipe 16 via a pipe mounting bracket 21 as in the examples shown in FIGS. 7 and 8. Piping mounting bracket 21 is for mounting band 3
8 detachably attached to the pipe 16.
In the aeration tank 73, air is injected into the sewage by an aeration blower or the like to promote the biological decomposition of the sewage. Aeration tank 7
The supernatant in the water in 3 is sent to the adjusting tank 74 by, for example, an overflow method. Water subjected to chemical treatment or the like in the adjusting tank 74 is sent to a separate tank for the next step by the underwater motor pump 72. At this time, the controller 20
A constant flow rate of water is supplied irrespective of the water level of the adjusting tank 74 using the above. The controller 20 is attached to the discharge pipe 16. In addition, similarly to the example of FIG.
6, a pressure sensor 45 connected to the controller 20 is provided. As described above, since the water treatment is continuously performed without storing the water in the tank, the size of the tank is reduced. That is, a tank having a minimum size that can secure a required residence time in the process may be used.

FIG. 11 is a block diagram of the controller 20. In FIG. 11, the motor pump is indicated by M, and the frequency converter is indicated by F. When three-phase AC is used as an input, the frequency converter F includes a converter portion including a rectifier circuit 81 for converting AC to DC, a smoothing capacitor 82 for smoothing the rectified voltage, and an inverter 83 for converting DC to AC. Consists of An auxiliary power supply section 84 and a voltage detection section 85 for detecting a DC voltage of the converter section are connected to the converter which is a DC section. The frequency converter F further includes a control unit 86 in which the relationship between the generated frequency and the current value is stored in advance, outputs a PWM signal from the control unit 86, and drives the inverter unit 83.

A current sensor 88 is provided at the output of the three-phase inverter 83, and the detected current is converted into a signal by the detector 87 and input to the controller 86. The motor 76 is connected to the output side of the three-phase inverter 83.
Reference numeral 89 denotes a temperature sensor. The control unit 86 includes:
A ROM for storing a function for specifying a generation frequency and a current value in advance, a CPU for comparing a signal from the current detection unit 87 with the contents set in the ROM, performing an arithmetic operation and outputting a predetermined PWM signal, and a control IC Is provided.

As described above, the current sensor 88 for detecting the value of the load current flowing through the motor is provided. When the control of the present invention is performed by a deep well submersible motor pump or the like, the rotation speed of the pump increases as the well water level decreases, and the load current value of the motor increases. Thereafter, when the water level further decreases, the pump section is exposed to the air, and a water shortage operation is performed. At this time, the pump sucks air and the load is reduced. Therefore, the pump is stopped by capturing the load with the current sensor 88. As a result, it is possible to prevent the service life of the pump bearing from being shortened due to the drought operation. In particular, due to the control characteristics, the pump is operated at the maximum rotational speed during the drought operation, so that the conditions for the bearing and the like are poor. Therefore, providing such a drought operation protection function is an important element in the practice of the present invention.

[0046]

As described above, according to the present invention, a constant flow rate operation irrespective of the well water level or the like can be realized by giving a constant flow rate to a pump using a pressure sensor. In addition, the above-described operation method can be easily realized by putting together a control device (controller) that can be retrofitted to the existing pump equipment. Further, by providing a function for protecting the pump from drought operation in the control device, the system of the present invention can be supplied as a more suitable one.

[Brief description of the drawings]

FIG. 1 is a side view showing a mounting example when a controller used in the present invention is used.

FIG. 2 is a diagram showing details of the apparatus shown in FIG. 1;

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a plan view of an operation board.

FIG. 5 is a diagram showing a circuit diagram inside a case.

FIG. 6 is a diagram showing a conventional snow melting system using a deep well submersible motor pump.

FIG. 7 is a diagram showing an existing system in which the operation method and the control device of the present invention are introduced.

FIG. 8 is a side view showing a state where the controller is attached to a pipe.

FIG. 9 is a diagram showing a relationship between a flow rate and a well outlet pressure.

FIG. 10 is an embodiment in which the operating method and the control device of the present invention are used for a submersible motor pump used in a water treatment facility.

FIG. 11 is a block diagram of a controller according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 pump unit 11 base 12 pump 13 motor 14 suction pipe 15 suction-side gate valve 16 pipe 17 check valve 18 discharge-side gate valve 18 19 discharge pipe 20 control device (controller) 21 pipe mounting bracket 21a open surface 22 control panel (power) Panel) 23 Cable connection box 24 Input cable 25 Output cable 28 Power cable 30 Frequency converter body (power module) 31 Backup circuit 32 Control circuit 33 Upper case 34 Lower case 35 Case 36 Sealing member 37 Bolt 38 Mounting band 40 Operation Substrate 41 Cap 42 Frequency adjustment knob 45 Pressure sensor 46 Signal cable 50 Input terminal 55 Input line 56 Switch 57 Output line 58 Switch 59 Detour line 60 Switch 61 Well 62 Deep well Submersible motor pump 62a Outlet 63 Feeding pipe 64 Control board 65 Power cable 66 Snowfall sensor 68 Buried piping 69 Nozzle 71 Raw water tank 72 Submersible motor pump for sewage 73 Aeration tank 74 Adjustment tank 76 Motor 81 Rectifier circuit 82 Smoothing capacitor 83 Inverter section 84 Auxiliary power supply section 85 Voltage detection unit 86 Control unit 87 Detection unit 88 Current sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) H02P 7/63 302 H02P 7/63 302D (72) Inventor Katsutoshi Iijima 11 No. 1 F-term in EBARA CORPORATION (Reference) 3H020 AA01 AA02 AA08 AA09 BA04 BA06 BA11 BA21 BA23 CA00 CA01 CA08 DA04 EA07 3H022 AA01 BA07 CA50 DA09 3H045 AA06 AA09 AA12 AA23 AA40 BA19 BA20 CA03 DA05 DA46 EA13 EA13 EA38 EA13 EA13 DD03 DD05 EE02 GG04 HA09 HB01 HB20 JJ03 JJ17 KK04 KK08 LL22 LL24 LL35 LL37 MM01 MM12 MM20 5H576 AA05 BB10 CC05 DD02 DD04 EE11 EE17 EE23 GG04 HA03 HB01 JJ03 JJ17 LL20 MM24 MM04

Claims (7)

[Claims] In a method of operating a motor pump used for a pump equipment in which pressure loss of a pump discharge side piping system does not change on a daily basis, a pressure sensor for detecting a discharge pressure of the pump and a discharge based on a signal from the pressure sensor. A control device that controls the rotation speed of the motor pump so that the pressure approaches the target value is provided, so that the amount of water per hour is substantially constant even if the pressure applied to the suction port of the pump changes. How to operate the motor pump. 2. A method for operating a deep well submersible motor pump for use in a pump facility in which pressure loss of a pump discharge side piping system does not change on a daily basis, comprising: a pressure sensor for detecting a discharge pressure at a ground portion of the pump; A control device that controls the rotation speed of the motor pump so that the discharge pressure approaches the target value based on the signal from the pressure sensor is provided so that the amount of water per hour is substantially constant even if the water level in the well changes. A method for operating a deep well submersible motor pump, characterized in that: 3. A method for operating a submersible motor pump used in a facility such as a water treatment facility in which pressure loss of a piping system on a pump discharge side does not change on a daily basis. A sensor and a control device that controls the rotation speed of the motor pump so that the discharge pressure approaches the target value based on the signal of the pressure sensor are provided, and even if the water level of the water tank in which the pump is installed changes, the amount of water per hour is substantially reduced. A method for operating a submersible motor pump, characterized in that the operation is constant. 4. A frequency converter, a case accommodating the frequency converter, power input / output means provided in the case, a pressure sensor, a signal input means of the pressure sensor provided in the case, and a case. And a switching means for switching a target value of the discharge pressure. 5. An existing pump system configured to intermittently operate a commercial well-driven deep well submersible motor pump, wherein a pressure sensor for detecting a discharge pressure of the pump above the ground and a discharge sensor based on a signal from the pressure sensor. A control device for controlling the rotation speed of the motor pump is increased so as to bring the pressure closer to the target value, so that even if the water level in the well changes, the amount of water per hour becomes substantially constant, and the control device includes a frequency converter. A case for accommodating the frequency converter, a power input / output means provided in the case, a pressure sensor, a signal input means for the pressure sensor provided in the case, and an attachment for attaching the case to the pump pipe. And pump means for switching the target value of the discharge pressure. 6. A snow melting system configured to intermittently operate a deep well submersible motor pump in accordance with snowfall intensity, a pressure sensor for detecting a discharge pressure of the pump above the ground, and a discharge pressure based on a signal from the pressure sensor. Is provided with a control device for controlling the rotation speed of the motor pump so as to approach the target value, so that even if the water level of the well changes, the amount of water per hour becomes substantially constant, the control device includes a frequency converter,
A case accommodating the frequency converter, power input / output means provided in the case, a pressure sensor, a signal input means of the pressure sensor provided in the case, and mounting means for mounting the case to the pump pipe; And a switching means for switching a target value of the discharge pressure. 7. An existing snow melting system configured to intermittently operate a deep well submersible motor pump driven by a commercial power supply in accordance with snowfall intensity, a pressure sensor for detecting a discharge pressure at a ground portion of the pump, and a pressure sensor. A control device for controlling the rotation speed of the motor pump so as to bring the discharge pressure closer to the target value based on the signal of the above, so that the amount of water per hour becomes substantially constant even if the water level of the well changes, The device includes a frequency converter, a case accommodating the frequency converter, power input / output means provided in the case, a pressure sensor, a signal input means of the pressure sensor provided in the case, and a pump piping. Mounting means for mounting to
A snow melting system comprising a switching means for switching a target value of a discharge pressure.