Water supply device

Abstract

To provide a water supply system that can detect abnormalities in the flow sensor even when the pressure on the primary side of the pump is high. [Solution] The water supply device comprises a motor, an inverter that controls the operating frequency of the motor, a pump connected to the motor, a pressure sensor provided on the secondary side of the pump that detects the discharge head, a flow sensor provided on the secondary side of the pump that outputs an ON signal at a predetermined flow rate, and a control unit that controls the inverter, performs constant estimated terminal pressure control, and stops the motor when the water flow rate is low. The control unit determines that the flow sensor is abnormal if, when the discharge head detected by the pressure sensor is less than or equal to the estimated terminal head, the operating frequency of the motor controlled by the inverter remains below the operating frequency of the motor at which the signal output by the flow sensor changes from an ON signal to an OFF signal immediately before stopping at the low water flow rate for a certain period of time.

Description

Technical Field

[0001] The present invention relates to a water supply device that performs drive control.

Background Art

[0002] Conventionally, in a water supply device, a technique for driving and controlling a pump unit using an inverter has been known. Such a water supply device performs drive control for starting and stopping the pump based on information acquired from sensors such as a flow rate sensor and a pressure sensor (see, for example, Patent Document 1).

[0003] For example, as the flow rate sensor, a paddle type flow rate sensor in which a paddle moves based on a predetermined flow rate is used. Then, the flow rate sensor outputs an ON signal and an OFF signal based on the position (flow rate) of the paddle, and the control unit performs drive control based on this signal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, when an abnormality such as breakage of the paddle of the flow rate sensor occurs, there is a risk of misrecognizing that the paddle has moved and the signal from the flow rate sensor becoming an ON signal. However, even if an abnormality has occurred in the flow rate sensor, if the pressure on the primary side of the pump (pushing pressure) is high, it is difficult to determine whether it is normal or abnormal, and the abnormality cannot be detected correctly, so it is not commonly used.

[0006] Therefore, an object of the present invention is to provide a water supply device that can detect an abnormality in a flow rate sensor even when the pressure on the primary side of the pump is high.

Means for Solving the Problems

[0007] According to one aspect of the present invention, the water supply device includes a motor, an inverter for controlling the operating frequency of the motor, a pump connected to the motor, a pressure sensor provided on the secondary side of the pump for detecting the discharge head, a flow sensor provided on the secondary side of the pump for outputting an ON signal at a predetermined flow rate, and a control unit for controlling the inverter, performing constant estimated terminal pressure control, and stopping the motor at a low water flow rate. The control unit determines that the flow sensor is abnormal if, when the discharge head detected by the pressure sensor is less than or equal to the estimated terminal head, the operating frequency of the motor controlled by the inverter remains below the operating frequency of the motor at which the signal output by the flow sensor changes from an ON signal to an OFF signal immediately before stopping at a low water flow rate for a certain period of time. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a water supply device that can detect abnormalities in the flow sensor even when the pressure on the primary side of the pump is high. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram illustrates the configuration of the water supply system according to this embodiment. [Figure 2] A block diagram showing the configuration of the water supply system. [Figure 3] A flowchart illustrating an example of the operation of the water supply system. [Figure 4] An explanatory diagram showing an example of the power consumption of the water supply system. [Modes for carrying out the invention]

[0010] The water supply device 3 according to this embodiment will be described below with reference to the drawings.

[0011] Figure 1 is an explanatory diagram showing the configuration of the water supply device 3 according to this embodiment, and Figure 2 is a block diagram showing the configuration of the water supply device 3. Figure 3 is a flowchart showing an example of determining an abnormality in the flow sensor 12 as an example of the operation of the water supply device 3, and Figure 4 is an explanatory diagram illustrating an example of power consumption when the pressure on the primary side of the pump 21 of the water supply device 3 is less than or equal to the estimated terminal head P2.

[0012] As shown in Figures 1 and 2, the water supply system 3 comprises one or more pump units 11, the same number of flow sensors 12 as the number of pump units 11, provided on the secondary side of each flow sensor 12, the same number of check valves 13 as the number of pump units 11, provided on the secondary side of each flow sensor 12, pressure sensors 14 provided on the secondary side of the multiple pump units 11, a pressure accumulator 15 provided on the secondary side of the pump units 11, and a control panel 50 for controlling the pump units 11. The water supply system 3 also includes various types of piping.

[0013] The flow sensor 12 and check valve 13 are provided on the secondary side of each of the multiple pump units 11. In this embodiment, as shown in Figures 1 and 2, the water supply device 3 is described using an example in which there are three pump units 11, but the number of pump units 11 may be one or two or more. The three pump units 11 are connected in parallel. For example, a branch pipe 16 is connected to the primary side of the three pump units 11. In addition, a confluence pipe 17 is connected to the secondary side of the three pump units 11, and the secondary side of the confluence section 17a of this confluence pipe 17 is connected to the water supply destination. Note that if there is only one pump unit 11, the branch pipe 16 and confluence pipe 17 are not provided, and general piping is used.

[0014] The branch pipe 16 has its primary side of the branch section 16a connected to the water supply source of the water branch pipe. In other words, the water supply device 3 is a direct-connection type water supply device, and the pressure on the primary side of the pump 21 is the pressure (pushing pressure) from the water branch pipe. The branch pipe 16 is a pipe to which the suction ports of the pump 21 are connected to the secondary side of the branch section 16a.

[0015] The merging pipe 17 is connected to the discharge ports of each pump 21 and is a pipe that merges on the secondary side of each pump 21. The merging pipe 17 includes a branch section 17b that branches in two directions on the secondary side of the merging section 17a, a pipe 17c connected to one side of the branch section 17b, and a branch pipe 17d connected to the other side of the branch section 17b. The pipe 17c is connected to the water supply pipe 210, which is the destination of the water supply, and the branch pipe 17d is connected to the pressure accumulator 15.

[0016] The pump unit 11 comprises a pump 21 as a rotating machine and a motor 22 as a rotating electric machine. The pump unit 11 may also have on-off valves on the primary side of the pump 21 and the secondary side of the check valve 13, which are formed to allow the flow path to be opened and closed manually, are used in an open state at all times, and are closed for maintenance or other purposes.

[0017] Pump 21, when driven, increases the pressure of water and supplies it to the secondary side. Pump 21 has an impeller fixed to a rotating shaft inside the pump casing, and when the rotating shaft is rotated by the motor 22, the impeller rotates and increases the pressure of the water. Such a pump 21 may be a single-stage pump having one impeller, or it may be a multi-stage pump having multiple impellers.

[0018] Motor 22 drives the pump 21. Motor 22 has, for example, a stator, a rotor, and a motor shaft, the motor shaft being connected to the rotation axis of the pump 21. Motor 22 is connected to an inverter 54 of the control panel 50, which will be described later.

[0019] The flow sensor 12 is a paddle-type flow sensor. The flow sensor 12 is provided for each pump unit 11 respectively, and detects the flow of water discharged from the secondary side of the pump unit 11, that is, the discharge port of the pump 21. As a specific example, the flow sensor 12 is provided on the secondary side of the pump 21 and on the primary side of the check valve 13. The flow sensor 12 detects a predetermined flow rate on the secondary side of each pump 21 on the secondary side of the pump 21 and on the primary side of the check valve 13. For example, the flow sensor 12 moves at a flow rate above a predetermined value and outputs an ON signal, and returns to the initial position at a flow rate below the predetermined value and outputs an OFF signal. Here, the output of the OFF signal may include not outputting a signal. Also, the predetermined flow rate at which the paddle moves from the position where the OFF signal is output to the position where the ON signal is output and the predetermined flow rate at which the paddle moves from the position where the ON signal is output to the initial position where the OFF signal is output may be different.

[0020] The check valve 13 is provided on the secondary side of the pump 21. As a specific example, it is provided at the discharge port of the pump 21 or on the pipe on the secondary side of the discharge port, and has a function of preventing the backflow of water to the pump 21 side. The check valve 13 includes a valve seat and a valve body that moves relative to the valve seat. The check valve 13 allows the valve body to separate from the valve seat by the water moving from the pump 21 to the secondary side of the pump 21 and allows the flow of water, and the valve body abuts against the valve seat by the water moving from the secondary side of the pump 21 toward the pump 21, preventing the water from moving from the secondary side of the pump 21 toward the pump 21.

[0021] The pressure sensor 14 is a pressure sensor. The pressure sensor 14 is provided on the confluence pipe 17. The pressure sensor 14 is connected to the control panel 50 and outputs the detected pressure information as a signal.

[0022] The accumulator 15 is, for example, an accumulator. The accumulator 15 can store water at a pressure above the starting pressure, for example. The volume of the accumulator 15 is appropriately set according to the usage conditions of the water supply device 3 and the like. Also, a plurality of accumulators 15 may be installed according to the usage conditions of the water supply device 3 and the like.

[0023] The control panel 50 controls the pump units 11 by alternating operation, which drives multiple pump units 11 alternately, or by parallel operation, which drives at least two of the multiple pump units 11 simultaneously. The control panel 50 also controls the multiple pump units 11 by estimated constant terminal pressure control as a target constant pressure control, based on at least one of the information obtained from various sensors, such as the flow rate value detected by the flow sensor 12, the pressure value detected by the pressure sensor 14, the frequency of the inverter 54, the piping resistance on the secondary side of the pump unit 11, and the pressure sensor installed on the secondary side of the confluence pipe 17. Furthermore, when the pump start condition is met, the control panel 50 starts driving the pump units 11 and drives the pump units 11 by estimated constant terminal pressure control, and when the pump stop condition is met, it terminates the estimated constant terminal pressure control and stops the pump units 11.

[0024] The pump starting condition is, for example, when the control panel 50 detects, as a starting pressure detection, that the pressure detected by the pressure sensor 14 (detected pressure PS1) has fallen to or below a predetermined pressure. The pump stopping condition is a so-called low-flow stop, where the secondary side of the pump 21 stops when the flow rate is low. The pump stopping condition is, for example, when the control panel 50 detects, as a low-flow detection, that the flow rate detected by the flow sensor 12 (output signal) is below a predetermined flow rate (OFF signal), and a predetermined time has elapsed. However, in addition to detecting the OFF signal, or instead of detecting the OFF signal, the motor 22 may be driven at a predetermined operating frequency for a predetermined time, for example, when the motor 22 is driven at the lowest operating frequency for a predetermined time, or when the motor 22 is driven at or below the operating frequency at which the signal from the flow sensor 12 switches from an ON signal to an OFF signal immediately before the low-flow stop (operating frequency Smin immediately before low-flow stop) for a predetermined time. Note that the operating frequency Smin immediately before the low-flow stop is a frequency higher than the lowest operating frequency.

[0025] As a specific example, as shown in Figure 2, the control panel 50 includes a communication device 51, an input device 53, an inverter 54, an interface 55, a display device 56, a storage device 57, and a processor 58 as a control unit, all connected to each other via a bus line.

[0026] The communication device 51 includes at least one of a short-range communication device and a long-range communication device. In the example of this embodiment, an example in which the communication device 51 includes both a short-range communication device and a long-range communication device will be described. For example, the short-range communication device is equipped with a wireless communication module compliant with wireless communication standards such as Bluetooth®, Wi-Fi, or NFC, and performs short-range wireless communication. The short-range communication device may also perform short-range communication using wired communication standards such as USB. The short-range communication device communicates with an external terminal via a short-range communication line to set the operating mode of the water supply device 3 and to send and receive various data.

[0027] The long-range communication device performs long-distance communication using wireless communication standards such as mobile communication networks, WiMAX, and Wi-Fi. The long-range communication device sends and receives various types of data to and from the management server or terminal via the long-range communication line.

[0028] For establishing wireless connections using short-range and long-range communication devices, for example, with Bluetooth, a wireless connection can be established through a standard pairing connection, and with Wi-Fi, a wireless connection can be established by entering the SSID and password pre-configured for the Wi-Fi access point. Once a wireless connection has been established between the water supply device 3 and the terminal, the wireless connection will be automatically established by turning on the terminal's wireless function and approaching the water supply device 3.

[0029] The input device 53 converts user instructions into electrical signals. The input device 53 may be, for example, an operation panel, touch panel, keyboard, mouse, or various switches. Alternatively, an audio input device may be used as the input device 53. The electrical signals from the input device 53 are supplied to the processor 58 via a bus.

[0030] The inverter 54 generates power to operate the pump unit 11. Specifically, the inverter 54 supplies AC power of a predetermined frequency to the motor 22. The inverter 54 also receives inverter control signals from the processor 58. The inverter 54 operates according to the inverter control signals. For example, the inverter 54 stops or starts operation according to an inverter control signal corresponding to an operation stop signal or an operation start signal. The inverter 54 also controls the rotational speed (rotational velocity) of the motor 22 by varying its frequency (operating frequency) according to an inverter control signal corresponding to a rotational speed control signal.

[0031] Specifically, the inverter 54 includes a converter circuit, a smoothing capacitor, and an inverter circuit. The converter circuit takes AC power from an AC power source and converts it into DC power by rectification. The smoothing capacitor smooths the voltage of the DC power output by the converter circuit to obtain DC power with a nearly constant voltage. The inverter circuit then converts the DC power obtained by the smoothing capacitor into AC power of a predetermined frequency corresponding to the inverter control signal (corresponding to a rotation speed control signal) from the control panel 50 and supplies it to the motor. The inverter 54 also has a temperature detector 59 that detects the temperature of the inverter 54. Here, the temperature of the inverter 54 detected by the temperature detector 59 is, for example, the internal temperature of the inverter 54. The temperature detector 59 outputs the detected temperature as a signal. The inverter 54 also has an abnormal temperature protection function that, for example, determines that the temperature is abnormal and forcibly stops the inverter if it becomes too hot.

[0032] The inverter 54 may not be located inside the control panel 50, but may be integrated with the motor 22. Furthermore, the temperature detector 59 may be provided in addition to, or instead of, the inverter 54, on the motor 22, the control panel 50, and / or on the control board or electronic components used in the control panel 50, and may be configured to detect the temperature of the motor 22, the temperature inside the control panel 50, the temperature of the control board used in the control panel 50, and / or the temperature of heat-generating electronic components used in the control board, etc.

[0033] Interface 55 is, for example, an input / output interface such as a port. Interface 55 connects the control panel 50 to various sensors, including the flow sensor 12 and the pressure sensor 14, and receives various signals.

[0034] The display device 56 displays various data. The display device 56 can be any display, such as a CRT display, liquid crystal display, organic EL display, LED display, or plasma display.

[0035] The storage device 57 is a memory device such as ROM, RAM, HDD, SSD, or integrated circuit memory device that stores various types of data. The storage device 57 may be implemented by a single physical memory device, or by multiple memory devices physically separated within the water supply device 3.

[0036] The memory device 57 stores various control settings as control information, such as starting pressure, stopping flow rate, target pressure, acceleration time, deceleration time, PI control setting value, first maximum operating frequency, second maximum operating frequency, and minimum operating frequency. The memory device 57 also stores programs for performing constant target pressure control, and programs for changing the maximum frequency as a control setting based on the temperature of the inverter 54 detected by the temperature detector 59. Here, the first maximum operating frequency is the frequency at which the operating current of the motor 22 is less than the rated maximum current of the inverter 54, and is set to a frequency higher than the second maximum operating frequency. Here, operating frequency means the rotational speed of the motor 22, and the first maximum operating frequency and second maximum operating frequency mean the upper limit of the rotational speed of the motor 22. The minimum operating frequency means the lower limit of the rotational speed of the motor 22.

[0037] Furthermore, the memory device 57 stores the estimated terminal head P2, the operating frequency Smin immediately before stopping the low flow rate, the set power consumption (threshold) β+γ, and the predetermined time α as control information for determining abnormalities in the flow sensor 12. Here, the estimated terminal head P2 is the head setting value on the low flow rate side when the estimated terminal pressure is constant. The set power consumption β+γ is the power value (kW) obtained by adding a preset margin γ to the power consumption β during the lowest operating frequency and / or low flow rate operation, which is set from previously measured values. The predetermined time α is a preset time.

[0038] The processor 58 is an arithmetic unit such as a CPU or microprocessor. The processor 58 may also be composed of dedicated circuits such as an ASIC or FPGA. The processor 58 is a control unit that executes various programs stored in the storage device 57 to realize the functions of a management device, such as the acquisition unit 581, the determination unit 582, the communication control unit 584, and the alarm generation unit 585.

[0039] The acquisition unit 581 acquires operating information of the pump unit 11. The operating information is the operating status of the pump unit 11, including multiple parameters related to the operation of the pump unit 11. Parameters included in the operating information include, for example, the voltage, current, and power supplied from the power supply to the control panel 50, the flow rate measured by each flow sensor 12, the pressure value (discharge head, detected pressure) detected by the pressure sensor 14, the operating frequency of the motor 22, the cumulative operating time, the number of operations, and liquid level (electrode) information. Liquid level information is, for example, information on the water level of the tank connected to the water supply device 3, such as full, low, empty, or normal, when a water storage tank (receiving tank) is used as a water source or as a water supply destination. The operating information may also include control setting values ​​such as acceleration time, deceleration time, PI control setting value, operating frequency, first / second maximum operating frequency, and minimum operating frequency.

[0040] Furthermore, the operating information includes the actual operating status of the pump 21 (motor 22). For example, the operating status includes the actual operating frequency of the motor 22, the flow rate value detected by the flow sensor 12, and the pressure value detected by the pressure sensor 14.

[0041] The determination unit 582 determines an abnormality in the flow sensor 12 based on the ON signal of the flow sensor 12, the operating frequency of the motor 22, power consumption, etc. Here, an abnormality in the flow sensor 12 is defined as the output of an ON signal due to paddle breakage, and the inability to output an OFF signal.

[0042] The communication control unit 584 controls the communication device 51 to transmit operating information and abnormal information from the flow sensor 12 to an external source. For example, the communication control unit 584 can transmit various types of information to the management server using a short-range or long-range communication device.

[0043] The alarm generation unit 585 issues an alert to the outside based on predetermined conditions, such as when the determination unit 582 determines that there is an abnormality in the flow sensor 12.

[0044] Furthermore, the number of circuit boards constituting the control panel 50 can be designed arbitrarily, and it is also possible to arbitrarily design which of the following devices—communicator 51, input device 53, inverter 54, interface 55, display device 56, storage device 57, and processor 58—is physically equipped on each circuit board. In addition, although the acquisition unit 581, determination unit 582, communication control unit 584, and alarm generation unit 585 are handled by a single processor 58, they may be shared by multiple physically separated processors.

[0045] Next, as a control method for the water supply device 3 according to this embodiment, a method for determining abnormalities in the flow sensor 12, which is an example of the operation of the water supply device 3, will be explained with reference to the flowchart shown in Figure 3.

[0046] First, while the pump 21 is stopped, if the pump start condition is not met (NO in step ST1), the processor 58 continues to stop the pump 21. If the pump start condition is met (YES in step ST1), it controls the motor 22 to start the pump 21 (step ST2). The processor 58 then drives the motor 22 using estimated constant terminal pressure control. If the pump stop condition is met (YES in step ST3), the processor 58 stops the motor 22 and the pump 21, and returns to step ST1.

[0047] If the pump stop condition is not met, the processor 58 acquires the signal output from the flow sensor 12 (step ST4). If the signal output from the flow sensor 12 is an OFF signal (NO in step ST4), the processor returns to step ST3. If the signal output from the flow sensor 12 is an ON signal (ON detection) (YES in step ST4), the processor 58 determines whether the discharge head (detected pressure) PS1 from the pump 21 detected by the pressure sensor 14 is less than or equal to the estimated end head P2 (step ST5).

[0048] If the detected pressure PS1 is less than or equal to the estimated end head P2 (YES in step ST5), the determination unit 582 of the processor 58 performs a primary side low pressure abnormality determination (1) as an abnormality determination of the flow sensor 12 when the primary side pushing pressure of the pump 21 is low.

[0049] As a specific example, the processor 58 determines whether the operating frequency of the motor 22 is less than or equal to the operating frequency Smin just before low-flow stop (step ST6). If the operating frequency of the motor 22 is greater than the operating frequency Smin just before low-flow stop (NO in step ST6), it determines that there is no abnormality in the flow sensor 12 and returns to step ST3. If the operating frequency of the motor 22 is less than or equal to the operating frequency Smin just before low-flow stop (YES in step ST6), the processor 58 monitors whether the state in which the operating frequency of the motor 22 is less than or equal to the operating frequency Smin just before low-flow stop continues for a predetermined time α (step ST7). For example, if the operating frequency of the motor 22 does not remain less than or equal to the operating frequency Smin just before low-flow stop for the predetermined time α, and the operating frequency of the motor 22 becomes greater than the operating frequency Smin just before low-flow stop (NO in step ST7), the processor 58 determines that there is no abnormality in the flow sensor 12 and returns to step ST3.

[0050] When the processor 58 (determination unit 582) detects that the operating frequency of the motor 22 has remained below the operating frequency Smin just before stopping the low water flow for a predetermined period of time α (YES in step ST7), it determines that there is an abnormality in the flow sensor 12 (step ST11).

[0051] Furthermore, in step ST5, if the detected pressure PS1 is greater than the estimated end head P2 (NO in step ST5), the determination unit 582 of the processor 58 performs a primary side high pressure abnormality determination (2) as an abnormality determination of the flow sensor 12 when the primary side pushing pressure of the pump 21 is high.

[0052] As a specific example, the processor 58 determines whether the operating frequency of the motor 22 is the minimum operating frequency (step ST8). If the operating frequency of the motor 22 is not the minimum operating frequency (NO in step ST8), it determines that there is no abnormality in the flow sensor 12 and returns to step ST3. If the operating frequency of the motor 22 is the minimum operating frequency (YES in step ST8), it determines whether the power consumption is less than the set power consumption β+γ, which is the power consumption under normal conditions (step ST9). If the power consumption is greater than or equal to the set power consumption β+γ (NO in step ST9), it determines that there is no abnormality in the flow sensor 12 and returns to step ST3.

[0053] If the power consumption is less than the set power consumption β+γ (YES in step ST9), the processor 58 monitors whether the state in which the power consumption is less than the set power consumption β+γ continues for a predetermined time α (step ST10). For example, if the state in which the power consumption is less than the set power consumption β+γ does not continue, and the power consumption becomes equal to or greater than the set power consumption β+γ (NO in step ST10), the processor 58 determines that there is no abnormality in the flow sensor 12 and returns to step ST3.

[0054] When the processor 58 (determination unit 582) detects that the power consumption has remained below the set power consumption β+γ for a predetermined period of time α (YES in step ST10), it determines that there is an abnormality in the flow sensor 12 (step ST11).

[0055] With the water supply system 3 configured in this way, it is possible to determine an abnormality in the flow sensor 12 when the pressure on the primary side of the pump 21 is equal to or less than the estimated end head P2, and when it is higher than that.

[0056] For example, we will explain why the primary side low pressure abnormality determination (1) is valid when the primary side pressure (inlet pressure) of pump 21 is less than or equal to the estimated terminal head P2. As a specific example, consider the case where the flow sensor 12 shows an OFF signal when motor 22 is operated at a flow rate of 0 L / min and an operating frequency of approximately 120 Hz, and the flow sensor 12 shows an ON signal when motor 22 is operated at a flow rate of 200 L / min and an operating frequency of approximately 150 Hz.

[0057] Even if the flow sensor 12 breaks and a constant ON signal is output, as shown in Figure 4, the operating frequency of the motor 22 decreases from approximately 120 Hz to 50 Hz at a flow rate of 0 L / min. Furthermore, at a flow rate of 200 L / min, the operating frequency of the motor 22 is maintained at approximately 150 Hz. Therefore, as described above, the point at which the flow rate is 0 L / min can be distinguished.

[0058] Furthermore, we will explain why, for example, if the primary pressure (injection pressure) of pump 21 is higher than the estimated end head P2, the primary high pressure abnormality determination (2) is valid. As a specific example, consider the case where, when motor 22 is operated at a flow rate of 0 L / min and the operating frequency is around 50 Hz, the flow sensor 12 shows an OFF signal, and when motor 22 is operated at a flow rate of 200 L / min and the operating frequency is around 50 Hz, the flow sensor 12 shows an ON signal.

[0059] In this case, if the flow sensor 12 is broken and a constant ON signal is output, the motor 22 will operate at approximately 50Hz at a flow rate of 0L / min and at approximately 50Hz at a flow rate of 200L / min, making it impossible to distinguish whether the flow sensor 12 is broken or not. However, power consumption [kW] is basically proportional to the flow rate, or approximates proportionality. For example, if the motor 22 is operated at approximately 50Hz at a flow rate of 0L / min, the power consumption will be α, and if the motor 22 is operated at approximately 50Hz at a flow rate of 200L / min, the power consumption will be α+β, so the difference in power consumption can be used to distinguish between the two. In other words, when the pressure on the primary side of the pump 21 is high, there are many ranges (flow rates) in which it can operate at the lowest frequency, but the power consumption is lowest when the flow rate is 0. Therefore, by using a set power consumption β+γ, which is the normal power consumption β with a margin γ, as a judgment condition, it is possible to detect an abnormality in the flow sensor 12.

[0060] In this way, regardless of the pressure (inlet pressure) on the primary side of the water supply device 3, the control unit 58 (software) can detect an abnormality in the flow sensor 12.

[0061] As described above, according to the water supply device 3 of the embodiment, in determining abnormalities, by using the normal operating power consumption β with a margin γ as one of the determination conditions, it is possible to detect abnormalities in the flow sensor 12 even when the pressure on the primary side of the pump 21 is high.

[0062] It should be noted that the present invention is not limited to the embodiments described above. For example, the water supply device 3 may automatically turn off its function under conditions where there is a risk of false detection in the abnormality determination of the flow sensor 12. In this case, false detection may be prevented by stopping detection (non-operation) when the operating frequency Smin immediately before stopping the low water flow rate reaches the lowest frequency.

[0063] In other words, the present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Furthermore, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple constituent elements disclosed. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention. [Explanation of symbols]

[0064] 3...Water supply device, 11...Pump unit, 12...Flow sensor, 13...Check valve, 14...Pressure sensor, 15...Pressure accumulator, 16...Branch pipe, 16a...Branch section, 17...Confluence pipe, 17a...Confluence section, 17b...Branch section, 17c...Piping, 17d...Branch pipe, 21...Pump, 22...Motor, 50...Control panel, 51...Communicator, 53...Input device, 54...Inverter, 55...Interface, 56...Display device, 57...Storage device, 58...Processor, 59...Temperature detector, 210...Water supply pipe, 581...Acquisition unit, 582...Determination unit, 584...Communication control unit, 585...Alert unit.

Claims

1. Motor and, An inverter that controls the operating frequency of the motor, A pump connected to the motor, A pressure sensor is provided on the secondary side of the pump to detect the discharge head, A flow sensor is provided on the secondary side of the pump and outputs an ON signal at a predetermined flow rate. A control unit that controls the inverter, performs constant estimated terminal pressure control, and stops the motor when the water level is low, Equipped with, The control unit determines the flow sensor to be abnormal when the discharge head detected by the pressure sensor is less than or equal to the estimated end head, and the operating frequency of the motor controlled by the inverter remains below the operating frequency of the motor at which the signal output by the flow sensor changes from an ON signal to an OFF signal just before stopping at a low water flow rate for a certain period of time.

2. The water supply device according to claim 1, wherein the control unit determines the flow sensor to be abnormal when the discharge head detected by the pressure sensor is greater than the estimated end head, the operating frequency of the motor controlled by the inverter is less than or equal to the minimum operating frequency of the motor, and the power consumption remains less than a threshold for a certain period of time.

3. The water supply device according to claim 2, wherein the threshold is set in advance from the measured value of the power consumption during the lowest operating frequency and / or low water flow operation, and a margin.

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