JP7741016B2 - Water supply device and method for operating the water supply device - Google Patents

Description

The present invention relates to a water supply device and a method for operating a water supply device.

Water supply systems are installed in buildings such as apartment complexes and offices, and are used to supply water to each water supply terminal (e.g., faucets). Variable-speed operation of pumps is commonly achieved in water supply systems using inverters that convert the frequency and voltage of commercial AC power to any desired frequency and voltage. Such water supply systems may be equipped with multiple inverters that control multiple pumps, each of which is controlled by a control unit. In water supply systems using multiple pumps and multiple inverters, if one pump motor fails (due to a current leak, overcurrent, or phase loss, for example), the system automatically switches to another pump motor, preventing a water outage for the building.

Furthermore, water supply devices have been developed that include a backup control board for the control board that controls the operation of the pump and inverter in case the operating control board stops functioning properly due to some kind of malfunction (see, for example, Patent Document 1). With such water supply devices, when a backup condition is met, such as an abnormality in the control board, control of the operation of the pump and inverter can be switched from the operating control board to a standby backup control board, thereby avoiding a water outage.

Japanese Patent Application Laid-Open No. 2005-351267

In conventional water supply systems, when switching inverter control from the operating control board to a backup control board, the pump and inverter are stopped first, and then the backup control board is used to restart the pump and inverter after a short period of time. The reason for this is that if the pump were to continue operating immediately after a backup condition, such as a control board abnormality, was met, there was a risk of an unexpected malfunction occurring in the water supply system. For this reason, a delay time was provided for the pump and inverter to allow the water supply system to restart safely. Therefore, conventionally, when switching operation and control of the pump and inverter from the operating control board to the backup control board, the water supply to the building would be stopped, albeit for a short time.

On the other hand, users and consumers of water supply equipment (hereinafter simply referred to as "users") tend to want to avoid interruptions to the water supply to buildings (i.e., water outages) as much as possible. As a result, many users would like to avoid water outages, even if only for a short time, and maintain a water supply to the building.

The present invention therefore aims to provide a water supply device and a method for operating a water supply device that can avoid water outages as much as possible.

In one aspect, a water supply device is provided that includes at least one pump, at least one inverter that variably controls the rotational frequency of the corresponding pump, and a main control board and a backup control board that can independently control the at least one inverter and are communicatively connected to each other, wherein the main control board and/or the backup control board monitor whether a backup condition for switching control of the at least one inverter from the main control board to the backup control board is met, and the backup control board determines whether to transfer operating status information of the at least one pump from the main control board to the backup control board depending on whether the backup condition is met.

In one aspect, the water supply device further includes a first pressure sensor connected to the main control board and measuring the discharge pressure of the at least one pump, and a second pressure sensor connected to the backup control board and measuring the discharge pressure of the at least one pump, and the backup conditions include an abnormality and/or failure of the first pressure sensor, and when the main control board and/or the backup control board detects an abnormality and/or failure of the first pressure sensor, the backup control board decides whether or not to transfer operating status information of the at least one pump from the main control board to the backup control board depending on the measurement value of the second pressure sensor.
In one aspect, the backup control board transfers operating status information of the at least one pump from the main control board to the backup control board when the measurement value of the second pressure sensor is within a predetermined tolerance range.
In one aspect, the water supply device further includes a first pressure sensor connected to the main control board and measuring the discharge pressure of the at least one pump, and a second pressure sensor connected to the backup control board and measuring the discharge pressure of the at least one pump, wherein the backup conditions include an abnormality and/or failure of the first pressure sensor, and when the main control board and/or the backup control board detect an abnormality and/or failure of the first pressure sensor, the backup control board stops the at least one pump.

In one aspect, the backup conditions include a communication abnormality between the main control board and the backup control board, and a communication abnormality between the main control board and the at least one inverter, and when the main control board and/or the backup control board detects a communication abnormality between the main control board and the backup control board, or a communication abnormality between the main control board and the at least one inverter, the backup control board transfers operating status information of the at least one pump from the main control board to the backup control board.
In one aspect, the backup condition includes an abnormality in the processing unit of the main control board, and when the main control board and/or the backup control board detects an abnormality in the processing unit of the main control board, the backup control board stops the at least one pump.

In one aspect, a water supply device is provided, comprising at least one pump, at least one inverter that variably controls the rotational frequency of the corresponding pump, a main control board and a backup control board that are capable of independently controlling the at least one inverter and are communicatively connected to each other, a first pressure sensor connected to the main control board that measures the discharge pressure of the at least one pump, and a second pressure sensor connected to the backup control board that measures the discharge pressure of the at least one pump, wherein the main control board and/or the backup control board monitor whether a backup condition for switching control of the at least one inverter from the main control board to the backup control board is met, and when the backup condition is met, the backup control board determines whether to transfer operating status information of the at least one pump from the main control board to the backup control board based on the measurement value of the second pressure sensor.

In one aspect, a method for operating a water supply device includes at least one pump, at least one inverter that variably controls the rotational frequency of the corresponding pump, and a main control board and a backup control board that are capable of independently controlling the at least one inverter and are communicatively connected to each other. The method monitors whether a backup condition for switching control of the at least one inverter from the main control board to the backup control board is met, and, depending on the backup condition that is met, determines whether operating status information for the at least one pump is to be transferred from the main control board to the backup control board.

In one aspect, the water supply device further includes a first pressure sensor connected to the main control board and measuring the discharge pressure of the at least one pump, and a second pressure sensor connected to the backup control board and measuring the discharge pressure of the at least one pump, and the backup conditions include an abnormality and/or failure of the first pressure sensor, and when an abnormality and/or failure of the first pressure sensor is detected, it determines whether or not to transfer the operating status information of the at least one pump from the main control board to the backup control board depending on the measurement value of the second pressure sensor.
In one aspect, the at least one pump is operated using terminal pressure estimation control, and when the measurement value of the second pressure sensor is within a predetermined tolerance range, operating status information of the at least one pump is handed over from the main control board to the backup control board.
In one aspect, the water supply device further includes a first pressure sensor connected to the main control board and measuring the discharge pressure of the at least one pump, and a second pressure sensor connected to the backup control board and measuring the discharge pressure of the at least one pump, and the backup conditions include an abnormality and/or failure of the first pressure sensor, and when the backup control board detects an abnormality and/or failure of the first pressure sensor, it stops the at least one pump.

In one aspect, the backup conditions include a communication abnormality between the main control board and the backup control board, and a communication abnormality between the main control board and the at least one inverter, and when a communication abnormality between the main control board and the backup control board or a communication abnormality between the main control board and the at least one inverter is detected, the backup control board transfers operating status information of the at least one pump from the main control board to the backup control board.
In one aspect, the backup condition includes an abnormality in the processing unit of the main control board, and when an abnormality in the processing unit of the main control board is detected, the backup control board stops the at least one pump.

In one aspect, a method for operating a water supply device includes at least one pump, at least one inverter that variably controls the rotational frequency of the corresponding pump, a main control board and a backup control board that are capable of independently controlling the at least one inverter and are communicatively connected to each other, a first pressure sensor connected to the main control board that measures the discharge pressure of the at least one pump, and a second pressure sensor connected to the backup control board that measures the discharge pressure of the at least one pump. The method monitors whether a backup condition for switching control of the at least one inverter from the main control board to the backup control board is met, and if the backup condition is met, determines whether to transfer operating status information of the at least one pump from the main control board to the backup control board based on the measurement value of the second pressure sensor.

According to this invention, depending on the backup conditions that are met, the backup control board takes over the operating status information for each pump that was controlled by the main control board. In other words, depending on the backup conditions that are met, the operation of each pump continues in its previous state, and there is no downtime. As a result, water outages to the building can be avoided as much as possible.

FIG. 1 is a schematic diagram showing a water supply device according to one embodiment. FIG. 2 is a schematic diagram showing a water supply device according to another embodiment. FIG. 3 is a schematic diagram illustrating an example of the inverter shown in FIG. FIG. 4 is a schematic diagram illustrating an example of the control unit illustrated in FIG. FIG. 5 is a block diagram showing the relationship between two control boards and a plurality of inverters. FIG. 6 is a schematic diagram showing an example of a backup control board. FIG. 7 is a flowchart for explaining a method for operating a water supply apparatus according to one embodiment. FIG. 8 is a flowchart for explaining a method of operating a water supply apparatus according to another embodiment.

Embodiments of the present invention will now be described with reference to the drawings. Note that in Figures 1 to 8, identical or corresponding components are designated by the same reference numerals, and redundant explanations will be omitted.

Figure 1 is a schematic diagram showing a water supply device according to one embodiment of the present invention. As shown in Figure 1, the water supply device includes three pumps 3 connected to a water tank 2 via piping 10, three motors 4 that drive the pumps 3, three inverters 5 that apply variable frequency voltages to the motors 4, and a control unit 6 that controls the inverters 5 and various other devices.

A water level detector 12 is located within the water receiving tank 2 to detect the water level in the water receiving tank 2. The water level detector 12 is equipped with multiple electrodes 12a and is capable of detecting multiple liquid levels (including full water, low water, recovery, and drought). Tap water is introduced into the water receiving tank 2 from a water supply pipe 14 connected to the water main (not shown) via a solenoid valve 16. The water level in the water receiving tank 2 is detected by the water level detector 12, and the solenoid valve 16 is opened and closed by the control unit 6 in response to increases or decreases in the water level. With this configuration, tap water is temporarily stored in the water receiving tank 2, and this stored water is then supplied by the pump 3 to end-users within a building such as a house.

Each discharge pipe 18 is connected to the discharge port of the pump 3, and these discharge pipes 18 are connected to a collecting pipe 20. Tap water is supplied to the end-user in the water tank 2 through the collecting pipe 20. Each discharge pipe 18 is equipped with a check valve 22 and a flow switch 24. The check valve 22 is a backflow prevention valve that prevents water from flowing back from the discharge side to the suction side when the pump 3 stops, and the flow switch 24 is a low-water-volume detector that detects when the water volume in the discharge pipe 18 is low. The output signal (low-water-volume detection signal) of the flow switch 24 is input to the control unit 6.

Pressure sensors 26 and 27 are installed in the collecting pipe 20 to detect the discharge-side pressure of the pump 3. These pressure sensors 26 and 27 are located close to each other and in the same position on the collecting pipe 20. The output signals of the pressure sensors 26 and 27 are input to the control unit 6. The pressure sensors 26 and 27 are respectively connected to two control boards (main control board and backup control board) provided in the control unit 6, which will be described later. Furthermore, a pressure tank 28 is connected to the collecting pipe 20. When the flow switch 24 detects a decrease in the water volume, the pump 3 accumulates pressure in the pressure tank 28 and then stops operating to prevent shut-off operation of the pump 3. Furthermore, although not shown, each pump 3 is equipped with a thermistor that measures the pump 3's temperature. The output signal of each thermistor (a signal indicating the pump temperature) is sent to the control unit 6.

Each inverter 5 is connected to a power source (commercial power supply) via an Earth Leakage Circuit Breaker (ELB) (not shown), and AC voltage is supplied from this power source to each inverter 5 via the ELB. Each inverter 5 converts the input AC voltage into DC voltage, drives switching elements such as IGBTs (Insulated Gate Bipolar Transistors) to convert it into AC voltage of the desired frequency (voltage with a frequency corresponding to information sent from the control unit 6), and applies this voltage to the motor 4 to drive it. The ELB is connected to the control unit 6 via a signal line (not shown), and a signal indicating operation of the ELB (i.e., cutoff of power supply) is sent to the control unit 6.

The ON/OFF and rotational speed (rotational frequency) of pump 3 are variably controlled using inverter 5 based on the output signals of various sensors, such as flow switch 24 and pressure sensor 26 (or pressure sensor 27). Typically, constant discharge pressure control is used to maintain a constant discharge pressure of pump 3 by controlling the rotational speed of pump 3 so that the discharge pressure detected by pressure sensor 26 (or pressure sensor 27) matches a set target pressure, or estimated constant terminal pressure control is used to maintain a constant supply water pressure at the end of the demand by appropriately changing the target value for discharge pressure of pump 3. These types of control enable pump 3 to be driven at a rotational speed appropriate to the amount of water demand at any given time, thereby achieving energy savings.

When the flow switch 24 is turned ON, it is determined that no water is being used, i.e., the water volume is low, and operation of the pump 3 is stopped. When water use is detected from a drop in the discharge pressure measured by the pressure sensor 26 (or pressure sensor 27), the pump 3 is restarted. When the pump 3 is stopped when the water volume is low, pressure accumulation operation is performed, in which the pump 3 is first accelerated and pressure is accumulated in the pressure tank 28 before the pump 3 is stopped.

The control unit 6 includes two control boards 60a, 60b that control the inverter 5, operation displays 70a, 70b that perform various settings and displays, and power supply boards 80a, 80b that supply power to the control boards 60a, 60b. The power supply board 80a and operation display 70a are connected to the control board 60a, and the power supply board 80b and operation display 70b are connected to the control board 60b. The power supply boards 80a, 80b have the same configuration, and the operation displays 70a, 70b also have the same configuration. In this embodiment, the power supply boards 80a, 80b are provided separately from the control boards 60a, 60b, but these power supply boards 80a, 80b may also be provided integrally with the control boards 60a, 60b, respectively. The control board 60a is connected to the water level detector 12, pressure sensor (first pressure sensor) 26, flow switch 24, thermistor, and earth leakage breaker; similarly, the control board 60b is connected to the water level detector 12, pressure sensor (second pressure sensor) 27, flow switch 24, thermistor, and earth leakage breaker.

The water level detector 12, pressure sensors 26 and 27, flow switch 24, and thermistor are physical quantity detectors that detect physical quantities necessary for controlling the operation of the pump 3. Hereinafter, these may be collectively referred to as physical quantity detectors. The control boards 60a and 60b control the operation of the pump 3 based on the physical quantity signals sent from these physical quantity detectors. For example, the control board 60a controls the rotational speed of the pump 3 based on the measured discharge pressure value sent from the pressure sensor 26. Furthermore, the control board 60a stops the operation of the pump 3 when the water level signal sent from the water level detector 12 indicates a drought.

Since control boards 60a and 60b have the same configuration, only control board 60a will be described below. Control board 60a is equipped with a communication unit (serial port) 61 connected to inverter 5, a memory unit (such as ROM or a flash memory unit, which is a rewritable non-volatile memory element) 62 that stores various programs, and an arithmetic processing unit (CPU) 63 that performs arithmetic control operations based on the programs stored in memory unit 62. Information such as the ON/OFF status and rotation speed of pump 3 and inverter 5 tripping is exchanged via communication unit 61. Memory unit 62 and arithmetic processing unit 63 may be mounted on the same semiconductor chip. Note that control boards 60a and 60b may control inverter 5 using analog signals rather than serial communication.

The control board 60a also has an input/output section (e.g., an input/output board) 65 equipped with input terminals for receiving output signals from the water level detector 12, pressure sensor 26, flow switch 24, thermistor, and earth leakage circuit breaker, and output terminals for outputting signals to the outside. Signals input to the input terminals include the water level signal for the water tank 2, the discharge pressure signal, the low water volume detection signal, the temperature signal for the pump 3, and an earth leakage signal. Signals output from the output terminals include signals indicating the state of the water tank 2 (full, low water, drought, malfunction, etc.), signals indicating malfunctions or abnormalities, and signals for operating the solenoid valve 16.

The control board 60a is connected to a power supply board (power supply unit) 80a. The memory unit 62 and arithmetic processing unit 63 of the control board 60a are powered by DC power supplied from the power supply board 80a. The arithmetic processing unit 63 executes a control program stored in the memory unit 62, determines the ON/OFF status (number of operating units) and operating speed of each pump 3 based on conditions set on the operation display 70a and signals from the physical quantity detector, and sends commands to the inverter 5 to control the rotational speed of the pumps 3. Furthermore, the arithmetic processing unit 63 performs control such as stopping operation of a pump 3 or switching operation to another pump 3 based on signals from the physical quantity detector and trip signals from the inverter 5.

Figure 2 is a schematic diagram showing a water supply device according to another embodiment. The configuration of this embodiment, which is not specifically described, is similar to the configuration of the embodiment shown in Figure 1, and therefore redundant description will be omitted.

The water supply device 1 shown in Figure 2 comprises two water tanks 2, a plurality of pumps 3 (two in Figure 2) connected to each water tank 2 via piping 10, a plurality of motors 4 (two in Figure 2) that drive each pump 3, a plurality of inverters 5 (two in Figure 2) that control the rotational frequency of each motor 4, and a control unit 6 that controls various devices including the inverters 5.

In this embodiment, two pressure sensors, a pressure sensor 26 (first pressure sensor) and a pressure sensor (second pressure sensor) 27, are installed in the discharge pipe 20 to detect the discharge pressure of the pump 3, and the output signals of these pressure sensors 26, 27 are input to the control unit 6. The pressure sensors 26, 27 are respectively connected to two control boards (main control board and backup control board) described below that are provided in the control unit 6. In this embodiment, the ON/OFF and rotational speed (rotational frequency) of the pump 3 are controlled using the inverter 5 based on the output signals of various sensors, such as the flow switch 24 and the pressure sensor 26 (or 27).

1, the water supply apparatus 1 has three pumps 3 and three inverters 5. In the embodiment shown in FIG. 2, the water supply apparatus 1 has two pumps 3 and two inverters 5. However, as long as each inverter 5 controls the rotation of each pump 3, the number of pumps 3 and inverters 5 is not limited to this example. For example, the water supply apparatus 1 may have one set of pumps 3 and inverters 5, or four or more sets of pumps 3 and inverters 5. Furthermore, in the embodiment shown in FIG. 1, the water supply apparatus 1 has one water receiving tank 2, while in the embodiment shown in FIG. 2, the water supply apparatus 1 has two water receiving tanks 2. However, the number of water receiving tanks 2 is not limited to these examples. For example, the water supply apparatus 1 may have three or more water receiving tanks 2. Alternatively, the water receiving tank 2 may be omitted. In this case, the water supply apparatus 1 is directly connected to a water main (not shown).

The water supply system 1 shown in Figures 1 and 2 is equipped with multiple pumps 3, allowing for multiple-unit operation with additional parallel-off, and if an abnormality is detected in a specific pump 3 or inverter 5 during operation, operation can be switched to another functioning pump 3 or inverter 5 to continue water supply.

Figure 3 is a schematic diagram showing an example of the inverter 5 shown in Figure 2. The inverter 5 shown in Figure 3 includes a main board 50, an operation panel 52 for configuring the inverter 5 (e.g., setting acceleration time, deceleration time, etc.), and an I/O board (input/output board) 54 for inputting and outputting various signals.

The main board 50 is equipped with a rectifier 500 that rectifies AC power input via an Earth Leakage Circuit Breaker (ELB) 56, a switching element (power unit) 501 that converts the power rectified by the rectifier 500 into AC power of the desired frequency, a communication unit (serial port) 502 that exchanges information with the control unit 6 and other inverters 5 via a serial communication cable 30, a memory unit (such as a ROM or a flash memory unit, which is a rewritable non-volatile memory element) 503 that stores various programs, and a calculation processing unit (CPU) 504 that performs calculation and control operations based on the programs stored in the memory unit 503.

The main board 50 converts the power input via the earth leakage breaker 56 into DC power using the rectifier 500, then drives a switching element 501 such as an IGBT (Insulated Gate Bipolar Transistor) to convert it into AC power of the desired frequency (power with a frequency corresponding to information sent from the control unit 6 via the communication unit 502), and supplies this power to the motor 4 that drives the pump 3.

The memory unit 503 stores programs for controlling the switching elements 501, sending and receiving information via the communication unit 502, and sending and receiving information with the I/O board 54 and operation panel 52, as well as various inverter control and operation control programs. These programs are executed by the arithmetic processing unit 504. The memory unit 503 and arithmetic processing unit 504 may be mounted on the same semiconductor chip. Because the memory unit 503, arithmetic processing unit 504, etc. are driven by DC power, the main board 50 of the inverter 5 is provided with a power supply unit 505 that supplies DC power to the main board 50. The power supply unit 505 may also supply power to the operation panel 52 and I/O board 54.

The I/O board 54 is equipped with various input and output terminals that can be freely modified depending on the intended use of the inverter 5. For example, the I/O board 54 has an analog input terminal 540 provided in each pump 3 to receive signals from a thermistor (not shown) that detects the temperature of the pump 3, a digital input terminal 541 to receive a trip signal from the earth leakage breaker 56 provided on the primary side of the inverter 5 and an ON/OFF signal from the flow switch 24 provided on the discharge side of the pump 3, and a digital output terminal 542 to output an operation signal indicating whether the pump 3 is operating (pump 3 ON/OFF signal) and a fault signal indicating a fault in the pump 3, inverter 5, or other component equipment to the outside of the device.

In this way, the I/O board 54 has input terminals for signals required for each pump series (input signals dependent on the pump 3), such as the thermistor, earth leakage breaker 56, and flow switch 24, and similarly has output terminals for signals required for each pump series (output signals dependent on the pump 3), such as operation and failure of the components provided in the water supply device 1. Therefore, there is no need to provide these input/output terminals in the control unit 6, and even if the number of pumps 3 increases, there is no need to prepare separate boards for input/output of these signals.

The I/O board 54 and main board 50 are connected to each other via interfaces 544 and 506. Signals input from the input terminals 540 and 541 of the I/O board 54 are transmitted from the communication unit 502 to the control unit 6 in accordance with a program stored in the memory unit 503 of the main board 50. In addition, based on the judgment of the control unit 6 or the arithmetic processing unit 504 of the main board 50, a fault signal is output to the outside from the output terminal 542 via the interfaces 506 and 544.

Figure 4 is a schematic diagram showing an example of the control unit shown in Figure 2. As shown in Figure 4, the control unit 6 includes two control boards 60a and 60b that input and output signals and control each pump series, and an operation panel 602 for performing various settings. The control unit 6 may have two operation panels 602 connected to the control boards 60a and 60b, respectively, or may have a common operation panel 602 for the control boards 60a and 60b. In this embodiment, the control boards 60a and 60b have the same configuration, so the following will describe the control board 60a.

The control board 60a is equipped with a communication unit (serial port) 600 that connects to the communication unit 502 of the inverter 5, a memory unit (such as a ROM or a flash memory unit, which is a rewritable non-volatile memory element) 62 that stores various programs, and an arithmetic processing unit (CPU) 63 that performs arithmetic control operations based on the programs stored in the memory unit 62. Operational information such as the ON/OFF status and rotation frequency of the pump 3, as well as abnormality and failure information such as tripping of the inverter 5, is exchanged between the control board 60a of the control unit 6 and the inverter 5 via the communication unit 600. The memory unit 62 and arithmetic processing unit 602 may be mounted on the same semiconductor chip.

The control board 60a also has an input terminal 603 to which signals related to the liquid level in the water tank 2 (output signal from the water level detector 12) and the like are input, an input terminal 604 to which an output signal from the pressure sensor 26 is input, an output terminal 605 for outputting an output signal to the solenoid valve 16, and an output terminal 606 for outputting the status of the water tank 2 (full, low water, drought, malfunction, etc.) to the outside.

In this embodiment, the control board 60a is provided with input/output terminals (input/output terminals independent of pump 3) that do not need to be provided for each pump series, such as signals related to the liquid level in the water tank 2, discharge pressure, and inflow pressure. However, as mentioned above, the input/output terminals required for each pump series (input/output terminals dependent on pump 3) are provided on the I/O board 54 of the inverter 5. As a result, the number of input/output terminals on the control board 60a is reduced, allowing for a more compact design. This is expected to result in cost savings.

The control board 60a is configured to execute a control program stored in the memory unit 62, determine the ON/OFF status (number of pumps to operate) and operating frequency of each pump 3 based on conditions set on the operation panel 602 and signals from various sensors, and transmit operating information including this information to the inverter 5 to control the rotation frequency of the pumps 3. The control board 60a is also configured to perform controls such as stopping operation of a pump 3 or switching operation to another pump 3 based on signals from various sensors and trip signals from the inverter 5.

The memory unit 62 and arithmetic processing unit 602 of the control boards 60a and 60b shown in Figure 4 are driven by DC power supplied from the power supply unit 505 of the main board 50 of the inverter 5 via the power terminal 507 (see Figure 3). In this way, by supplying power for the control boards 60a and 60b of the control unit 6 from the inverter 5, there is no need to provide a separate DC power supply for the control boards 60a and 60b. This reduces the manufacturing cost of the water supply device and also reduces the size of the control boards 60a and 60b.

In one embodiment, as shown in FIG. 1, DC power may be supplied to the control boards 60a and 60b from power supply boards 80a and 80b included in the control unit 6. Alternatively, a power supply circuit (not shown) to which a commercial power source is connected may be provided on the control boards 60a and 60b, and DC power may be generated via the power supply circuit.

Figure 5 is a block diagram showing the relationship between two control boards and multiple inverters. As described above, the two control boards 60a and 60b have the same configuration, are connected to each other via communication means such as serial communication, and monitor each other's communications. Each control board 60a and 60b is configured to independently control all inverters 5. Therefore, even if one control board 60a (or 60b) experiences an abnormality (CPU abnormality, communication abnormality, system abnormality, etc.), the other standby control board 60b (or 60a) can back up the inverters 5, allowing the water supply system to continue operating at its maximum water flow rate and avoiding a water outage. When this backup control is activated, the control board 60a and/or 60b outputs an abnormality occurrence signal and a backup start signal to the outside of the water supply system 1 via output terminal 606. The backup start signal indicates that backup control has started.

Which of the control boards 60a and 60b is given priority can be set as desired. For ease of explanation, below, the control board 60a will be referred to as the "main control board 60a," which primarily (or preferentially) controls the operation of each pump 3 and each inverter 5, and the control board 60b will be referred to as the "backup control board 60b." The backup control board 60b functions as a control board that backs up the operation control of the pumps 3 and inverter 5 when a backup condition is met, such as when an abnormality occurs in the main control board 60a.

In one embodiment, the main control board, which primarily (or preferentially) controls the operation of the pump 3 and inverter 5, may be switched between control board 60a and control board 60b as needed. For example, if the operating program of the water supply device 1 needs to be updated, a new program is installed in the memory unit 62 of the standby backup control board 60b (or 60a), and then control board 60b (or 60a) is switched to the main control board, placing the previously used control board 60a (or 60b) in a standby state where it can be used as a backup. Furthermore, the program on the standby control board 60a (or 60b) can also be rewritten, and the startup programs of both control boards 60a and 60b can be updated. These operations make it possible to rewrite the program with a new one without stopping the operation of the water supply device 1.

In the above-described embodiment, an example was described in which the control boards 60a and 60b have the same configuration, but the main control board 60a and backup control board 60b do not necessarily have to have the same configuration as long as they have the minimum configuration necessary to control the pump 3 and inverter 5. For example, as shown in Figure 6, the configuration of the backup control board 60b may be simplified to have the minimum configuration necessary to control the pump 3 and inverter 5. Figure 6 is a schematic diagram showing an example of a backup control board. This configuration can reduce the overall cost of the water supply device 1.

Next, we will explain how to operate the water supply device 1, including the backup operation that switches control of each pump 3 and each inverter 5 from the main control board 60a to the backup control board 60b.

Figure 7 is a flowchart illustrating a method for operating a water supply device according to one embodiment. As shown in Figure 7, when the water supply device 1 is started, the main control board 60a operates each pump 3 based on output signals from various sensors, such as the measurement value of the pressure sensor (first pressure sensor) 26 connected to the main control board 60a and the output of the flow switch 24 (S101). More specifically, the main control board 60a controls each inverter 5 based on the output signals from the various sensors, operating each pump 3 using the constant discharge pressure control or constant estimated terminal pressure control described above. In this state, the main control board 60a monitors whether a backup condition is met for switching control of each inverter 5 from the main control board 60a to the backup control board 60b (S102). In one embodiment, monitoring for whether the backup condition is met may be performed by the backup control board 60b, which is communicatively connected to the main control board 60a, or by both the main control board 60a and the backup control board 60b.

The backup conditions correspond to abnormalities in the water supply system 1 that require switching control of each inverter 5 from the main control board 60a to the backup control board 60b, and are pre-stored in the memory unit 62 of the main control board 60a. The backup conditions include at least an abnormality in the arithmetic processing unit (CPU) 602 of the main control board 60a, a communication abnormality between the main control board 60a and each inverter 5, a communication abnormality between the main control board 60a and the backup control board 60b, and an abnormality (or failure) of the pressure sensor 26 connected to the main control board 60a. In one embodiment, the backup conditions may also include an abnormality (or failure) of several components, such as a thermistor (not shown) that detects the temperature of the pump 3 and a pressure sensor (not shown) that measures the inflow pressure of water to the water supply system.

If the backup conditions are not met (NO in S102), the main control board 60a continues to control each inverter 5 to operate each pump 3. If any one of the backup conditions is met (YES in S102), the main control board 60a switches control of each inverter 5 from the main control board 60a to the backup control board 60b (S103). At the same time, the backup control board 60b determines whether to transfer the operating status information of each pump 3 from the main control board 60a to the backup control board 60b, depending on the met backup condition (S104). The operating status information of each pump 3 includes at least the ON/OFF status and rotation frequency that the main control board 60a transmitted to each pump 3 via each inverter 5.

The backup control board 60b pre-stores backup conditions under which the operating status information of each pump 3 can be inherited, and backup conditions under which the operating status information of each pump 3 cannot be inherited. Backup conditions under which the operating status information of each pump 3 can be inherited are, for example, backup conditions under which it is expected that no malfunctions will occur in the water supply device 1 even if each pump 3 is operated in the previous operating status, and are selected in advance from all backup conditions.

For example, among the backup conditions, a communication abnormality between the main control board 60a and each inverter 5 and a communication abnormality between the main control board 60a and backup control board 60b are simply communication abnormalities, and therefore the main control board 60a (particularly the arithmetic processing units 63, 602 of the main control board 60a) and the pressure sensor 26 are considered to be in a normal state. In other words, the operating status of each pump 3 is considered to be normal. Therefore, when a backup condition is met that indicates the operating status of each pump 3 is normal, such as a communication abnormality, the backup control board 60b takes over the operating status information of each pump 3 that the main control board 60a controlled via each inverter 5, and continues operating each pump 3 without stopping it (S105).

On the other hand, an abnormality in the main control board 60a (particularly an abnormality in the arithmetic processing units 63, 602 of the main control board 60a) may result in abnormal command values sent to each inverter 5, which may result in the operating state of each pump 3 deviating from its normal state. Therefore, if a backup condition is met that indicates the operating state of each pump 3 may deviate from its normal state, such as an abnormality in the main control board 60a, the backup control board 60b temporarily stops all pumps 3 without taking over the operating state information of each pump 3 from the main control board 60a (S106). This action prevents unexpected malfunctions from occurring in the water supply system 1. The backup control board 60b then controls each inverter 5 based on the measurement value of the pressure sensor 27 and the output of the flow switch 24, and restarts each pump 3 using the above-mentioned constant discharge pressure control or constant estimated terminal pressure control (S107).

If all flow switches 24 are ON when the backup conditions are met, it is assumed that no water is being used in the building, or that very little water is being used. In this case, the backup control board 60b may temporarily stop all pumps 3 (S106). The backup control board 60b then restarts each pump 3 using the above-mentioned constant discharge pressure control or constant estimated terminal pressure control (S107).

If one of the backup conditions, namely, an abnormality in the pressure sensor 26, is met, the main control board 60a may have been controlling each inverter 5 based on incorrect discharge pressure information. Therefore, in this embodiment, if one of the backup conditions, namely, an abnormality in the pressure sensor 26, is met, the backup control board 60b temporarily stops all pumps 3 (S106).

In one embodiment, if one of the backup conditions, namely an abnormality in the pressure sensor 26, is met, the backup control board 60b may determine whether or not to transfer the operating status information of each pump 3 from the main control board 60a to the backup control board 60b, depending on the measurement value of the pressure sensor 27. The reason for this is that if the measurement value of the pressure sensor (second pressure sensor) 27 connected to the backup control board 60b is within the allowable range for operating the water supply device 1, it is believed that unexpected malfunctions will not occur in the water supply device 1 even if the backup control board 60b begins control of each inverter 5 while having inherited the operating status information of each pump 3 from the main control board 60a.

The allowable range of measurement values of the pressure sensor 27 that allows the water supply device 1 to operate is pre-stored in the memory unit 62 of the backup control board 60b. The allowable range of measurement values of the pressure sensor 27 that allows the water supply device 1 to operate can be determined in advance, for example, through experiments. Alternatively, the allowable range of measurement values of the pressure sensor 27 that allows the water supply device 1 to operate may be determined in consultation with the user based on the performance of the water supply device 1, the performance of the building, and the performance of the piping connecting them. Alternatively, the allowable range of measurement values of the pressure sensor 27 that allows the water supply device 1 to operate may be the pressure range listed in the pump selection chart used when selecting the pump 3 of the water supply device 1. When selecting the pump 3 of the water supply device 1, the optimal pump is selected from the pump selection chart based on the total head and water supply volume requested by the customer. If the pressure sensor 27 measurement value is within the pump pressure range set forth in this pump selection diagram, the water supply device 1 can be operated without any problems even if the backup control board 60b begins control of each inverter 5 while taking over the operating status information of each pump 3 from the main control board 60a.

When the main control board 60a and backup control board 60b control the operation of each inverter 5 using estimated terminal pressure control, the main control board 60a and backup control board 60b pre-store the maximum and minimum discharge pressure values. Therefore, the upper and lower limits of the allowable range of the pressure sensor 27 measurement values within which the water supply device 1 can be operated may be set to these maximum and minimum discharge pressure values. In this case, if the pressure sensor 27 measurement values are within the allowable range determined by the maximum and minimum discharge pressure values, the backup control board 60b begins control of each inverter 5 while transferring the operating status information of each pump 3 to the main control board 60a (S105). On the other hand, if the pressure sensor 27 measurement values are outside the allowable range determined by the maximum and minimum discharge pressure values, the backup control board 60b temporarily stops all pumps 3 without transferring the operating status information of each pump 3 from the main control board 60a (S106).

In one embodiment, when the main control board 60a and backup control board 60b control the operation of each inverter 5 using estimated terminal pressure control, the allowable range of measurements from the pressure sensor 27 that allows the water supply device 1 to operate may be used as the target pressure range for estimated terminal pressure control. The target pressure range is a pressure range determined by the target discharge pressure when the pump 3 is operated at the maximum water volume (rated water volume) and the target discharge pressure when the pump 3 is operated at the minimum water volume.

When the backup conditions are met in S102 and the backup control board 60b is started (S103), an alarm indicating this is issued from the water supply device 1. This allows the operator who receives the alarm to perform maintenance and/or repairs on the water supply device 1 to resolve the backup conditions (S108).

In this way, according to this embodiment, depending on the backup conditions that are met, the backup control board 60b takes over the operating status information of each pump 3 that was controlled by the main control board 60a and controls each inverter 5. In other words, depending on the backup conditions that are met, the operation of each pump 3 continues in its previous state and the operation of each pump 3 does not stop. As a result, water outages to the building can be avoided as much as possible.

Figure 8 is a flowchart illustrating a method for operating a water supply device according to another embodiment. The configuration of this embodiment that is not specifically described is the same as the embodiment described above, so redundant description will be omitted.

In this embodiment, when control of each inverter 5 is switched from the main control board 60a to the backup control board 60b in S103, the backup control board 60b determines whether or not to transfer the operating status information of each pump 3 from the main control board 60a to the backup control board 60b, based on the measurement value of the pressure sensor (second pressure sensor) 27. In other words, regardless of the backup condition that has been met, the backup control board 60b determines whether or not to transfer the operating status information of each pump 3 from the main control board 60a to the backup control board 60b, based on the measurement value of the pressure sensor 27 (S104).

As described above, if the measurement value of the pressure sensor 27 is within the allowable range for operating the water supply device 1, it is believed that no unexpected malfunctions will occur in the water supply device 1 even if the backup control board 60b begins control of each inverter 5 while the operating status information of each pump 3 is handed over to the main control board 60a. Therefore, in this embodiment, if the backup condition is met (YES in S103), the backup control board 60b checks whether the measurement value of the pressure sensor (second pressure sensor) 27 is within a predetermined allowable range (S104).

If the measurement value of the pressure sensor 27 is within the allowable range (YES in S104), the backup control board 60b takes over the operating status information of each pump 3 that the main control board 60a controlled via each inverter 5, and continues operating each pump 3 (S105). On the other hand, if the measurement value of the pressure sensor 27 is outside the allowable range (NO in S104), the backup control board 60b temporarily stops all pumps 3 (S106).

This type of control makes it possible to continue operating each pump 3 as long as possible, regardless of the backup conditions. As a result, water outages to the building can be avoided as much as possible.

The above-described embodiments have been described with the aim of enabling a person of ordinary skill in the art to practice the present invention. Various modifications to the above-described embodiments would naturally be possible for a person skilled in the art, and the technical concept of the present invention may also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope in accordance with the technical concept defined by the claims.

REFERENCE SIGNS LIST 1 Water supply device 2 Water receiving tank 3 Pump 4 Motor 5 Inverter 6 Control unit 12 Water level detector 24 Flow switch 26, 27 Pressure sensor 28 Pressure tank 30 Communication cable 60a Main control board 60b Backup control board 62 Memory unit 63 Arithmetic processing unit (CPU)
502, 600 Communication unit 503 Storage unit 504 Processing unit (CPU)

Claims (14)

at least one pump;
At least one inverter for variably controlling the rotation frequency of the corresponding pump;
a main control board and a backup control board that are capable of independently controlling the at least one inverter and are communicatively connected to each other;
the main control board and/or the backup control board monitor whether a backup condition for switching control of the at least one inverter from the main control board to the backup control board is satisfied;
A water supply device in which, if the backup condition that is met is a backup condition in which the operating status of the at least one pump is considered to be normal, the backup control board transfers the operating status information of the at least one pump from the main control board to the backup control board, and continues operating the at least one pump without stopping it. a first pressure sensor connected to the main control board for measuring a discharge pressure of the at least one pump;
a second pressure sensor connected to the backup control board and configured to measure a discharge pressure of the at least one pump;
the backup condition includes an abnormality and/or a failure of the first pressure sensor;
A water supply device as described in claim 1, wherein when the main control board and/or the backup control board detects an abnormality and/or failure of the first pressure sensor, the backup control board transfers the operating status information of the at least one pump from the main control board to the backup control board and continues operation of the at least one pump without stopping it, if the measurement value of the second pressure sensor is within the allowable range for operating the water supply device. The water supply device described in claim 2, wherein the backup control board transfers operating status information of the at least one pump from the main control board to the backup control board when the measurement value of the second pressure sensor is within a predetermined tolerance range, and continues operating the at least one pump without stopping it. a first pressure sensor connected to the main control board for measuring a discharge pressure of the at least one pump;
a second pressure sensor connected to the backup control board and configured to measure a discharge pressure of the at least one pump;
the backup condition includes an abnormality and/or a failure of the first pressure sensor;
The water supply device of claim 1, wherein when the main control board and/or the backup control board detects an abnormality and/or failure of the first pressure sensor, the backup control board stops the at least one pump. the backup condition includes a communication abnormality between the main control board and the backup control board, and a communication abnormality between the main control board and the at least one inverter;
A water supply device as described in any one of claims 1 to 4, wherein when the main control board and/or the backup control board detects a communication abnormality between the main control board and the backup control board, or a communication abnormality between the main control board and the at least one inverter, the backup control board transfers the operating status information of the at least one pump from the main control board to the backup control board and continues operation of the at least one pump without stopping it. the backup condition includes an abnormality in the arithmetic processing unit of the main control board,
A water supply device as described in any one of claims 1 to 5, wherein when the main control board and/or the backup control board detects an abnormality in the calculation processing unit of the main control board, the backup control board stops at least one of the pumps. at least one pump;
At least one inverter for variably controlling the rotation frequency of the corresponding pump;
a main control board and a backup control board that are capable of independently controlling the at least one inverter and are communicatively connected to each other;
a first pressure sensor connected to the main control board for measuring a discharge pressure of the at least one pump;
a second pressure sensor connected to the backup control board and configured to measure a discharge pressure of the at least one pump;
the main control board and/or the backup control board monitor whether a backup condition for switching control of the at least one inverter from the main control board to the backup control board is satisfied;
When the backup condition is met, the backup control board transfers the operating status information of the at least one pump from the main control board to the backup control board, and continues operating the at least one pump without stopping it , if the measurement value of the second pressure sensor is within the allowable range for operating the water supply device. A method for operating a water supply device comprising at least one pump, at least one inverter that variably controls the rotational frequency of the corresponding pump, and a main control board and a backup control board that can independently control the at least one inverter and are communicatively connected to each other, comprising:
monitor whether a backup condition for switching control of the at least one inverter from the main control board to the backup control board is satisfied;
A method for operating a water supply device, in which, if the established backup condition is one in which the operating status of the at least one pump is considered to be normal, the operating status information of the at least one pump is transferred from the main control board to the backup control board, and the operation of the at least one pump continues without being stopped. The water supply device further includes a first pressure sensor connected to the main control board and measuring a discharge pressure of the at least one pump, and a second pressure sensor connected to the backup control board and measuring a discharge pressure of the at least one pump,
the backup condition includes an abnormality and/or a failure of the first pressure sensor;
A method for operating a water supply system as described in claim 8, wherein when an abnormality and/or failure of the first pressure sensor is detected, if the measurement value of the second pressure sensor is within an allowable range for operating the water supply system, the operating status information of the at least one pump is transferred from the main control board to the backup control board, and operation of the at least one pump continues without being stopped. the at least one pump is operated under tip pressure estimation control;
A method for operating a water supply system as described in claim 9, wherein when the measurement value of the second pressure sensor is within a predetermined tolerance range, operating status information of the at least one pump is transferred from the main control board to the backup control board, and operation of the at least one pump is continued without being stopped. The water supply device further includes a first pressure sensor connected to the main control board and measuring a discharge pressure of the at least one pump, and a second pressure sensor connected to the backup control board and measuring a discharge pressure of the at least one pump,
the backup condition includes an abnormality and/or a failure of the first pressure sensor;
9. The method for operating a water supply apparatus according to claim 8, wherein the backup control board stops the at least one pump when an abnormality and/or failure of the first pressure sensor is detected. the backup condition includes a communication abnormality between the main control board and the backup control board, and a communication abnormality between the main control board and the at least one inverter;
A method for operating a water supply system as described in any one of claims 8 to 11, wherein when a communication abnormality is detected between the main control board and the backup control board, or between the main control board and the at least one inverter, the backup control board transfers the operating status information of the at least one pump from the main control board to the backup control board, and continues operation of the at least one pump without stopping it. the backup condition includes an abnormality in the arithmetic processing unit of the main control board,
13. A method for operating a water supply apparatus according to claim 8, wherein when an abnormality is detected in the arithmetic processing unit of the main control board, the backup control board stops the at least one pump. A method for operating a water supply device comprising at least one pump, at least one inverter that variably controls the rotational frequency of the corresponding pump, a main control board and a backup control board that are capable of independently controlling the at least one inverter and are communicatively connected to each other, a first pressure sensor connected to the main control board and that measures the discharge pressure of the at least one pump, and a second pressure sensor connected to the backup control board and that measures the discharge pressure of the at least one pump,
monitor whether a backup condition for switching control of the at least one inverter from the main control board to the backup control board is satisfied;
A method for operating a water supply system in which, when the backup condition is met, if the measurement value of the second pressure sensor is within an allowable range for operating the water supply system, the operating status information of the at least one pump is transferred from the main control board to the backup control board, and the operation of the at least one pump continues without being stopped.