Operation inspection device, water supply device, inspection method for operation inspection device, and maintenance method for operation inspection device

Abstract

To provide an operation inspection device capable of determining its own abnormality.SOLUTION: An operation inspection device 50 includes an intermediate chamber pressure sensor 55 that detects the pressure in an intermediate chamber of a backflow prevention device 15. The intermediate chamber pressure sensor 55 is configured to detect a pressure signal as an indicator for determining an abnormality in an opening and closing valve 53.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an operation inspection device, a water supply device, an inspection method for the operation inspection device, and a maintenance method for the operation inspection device. [Background technology]

[0002] There is known a water supply system that is connected directly to a water main or via a water tank and supplies water from the water main to water supply fixtures (e.g., faucets) in a building. In order to prevent water from flowing back into the water main or the water tank, a backflow prevention device is attached to the suction pipe of the water supply system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-105389 A Summary of the Invention [Problem to be solved by the invention]

[0004] Backflow prevention devices are required to be inspected about once a year. Conventionally, a specialist would have to access the water supply system in the pump room and inspect the backflow prevention device using a test kit. During this inspection, the water supply system must be shut down and the water supply must be cut off.

[0005] However, in this method, a professional must directly access the water supply system and connect a test kit for inspection to the backflow prevention device, which may result in the inspection work being complicated.

[0006] Therefore, an operation inspection device is provided that easily inspects the operation of the backflow prevention device without the troublesome task of connecting a test kit to the backflow prevention device. However, in order to ensure the normal operation of the backflow prevention device, it is necessary that no abnormality occurs in the operation inspection device. If an abnormality occurs in the operation inspection device, it may not be possible to properly inspect the backflow prevention device, and there is also a risk that the inspection result of the backflow prevention device may be erroneously determined.

[0007] Therefore, an object of the present invention is to provide an operation inspection device capable of determining an abnormality in the device itself, and a water supply device equipped with an operation inspection device.

[0008] An object of the present invention is to provide an inspection method for an operation inspection device that can determine an abnormality in the operation inspection device itself, and a maintenance method for the operation inspection device. [Means for solving the problem]

[0009] In one aspect, there is provided an operation inspection device including a connecting pipe connected to a backflow prevention device, an on-off valve for opening and closing the connecting pipe, and an intermediate chamber pressure sensor for detecting a pressure in an intermediate chamber of the backflow prevention device. The intermediate chamber pressure sensor is configured to detect a pressure signal as an index for determining an abnormality of the on-off valve when the on-off valve opens and closes with the connecting pipe filled with liquid.

[0010] In one embodiment, the intermediate chamber pressure sensor is configured to detect a pressure signal as an indicator for determining an abnormality in the intermediate chamber pressure sensor based on a comparison result with a suction side pressure signal detected by a suction side pressure sensor arranged on the suction side of the backflow prevention device, and / or a comparison result with a discharge side pressure signal detected by a discharge side pressure sensor arranged on the discharge side of the backflow prevention device. In one aspect, the operation inspection device is provided with a check valve arranged upstream of the on-off valve in the flow direction of liquid flowing through the connecting pipe, and the intermediate chamber pressure sensor is configured to detect a pressure signal as an indicator for determining an abnormality in the check valve when the on-off valve opens and closes when the connecting pipe is filled with liquid. In one aspect, the intermediate chamber pressure sensor is configured to detect a pressure signal as an indicator for determining whether water is leaking from the connecting pipe when the opening / closing valve is opening and closing when the connecting pipe is filled with liquid.

[0011] In one aspect, a water supply system is provided that includes a pump device, an operation inspection device for inspecting the operation of a backflow prevention device arranged on the suction side of the pump device, and a control device for determining an abnormality in the operation inspection device. The operation inspection device includes a connecting pipe connected to the backflow prevention device and an on-off valve for opening and closing the connecting pipe, and the control device is configured to determine an abnormality in the on-off valve based on a pressure signal detected by a discharge pipe pressure sensor connected to a discharge pipe arranged on the discharge side of the pump device and a water leakage detection signal detected by a water leakage detector of the backflow prevention device when the on-off valve opens and closes with the connecting pipe filled with liquid.

[0012] In one aspect, the control device is configured to determine whether there is water leakage from the connecting pipe based on the pressure signal detected by the discharge pipe pressure sensor when the opening and closing operation of the on-off valve is performed while the connecting pipe is filled with liquid. In one aspect, the operation inspection device includes a strainer attached to the connecting pipe, and the control device is configured to determine whether the strainer is clogged based on a leak detection signal detected by the leak detector when the opening and closing operation of the on-off valve is performed with the connecting pipe filled with liquid.

[0013] In one aspect, a water supply system is provided that includes a pump device, an operation inspection device for inspecting the operation of a backflow prevention device arranged on the suction side of the pump device, and a control device for determining an abnormality in the operation inspection device. The operation inspection device includes a connecting pipe connected to the backflow prevention device and an on-off valve for opening and closing the connecting pipe, and the control device periodically repeats the opening and closing operation of the on-off valve while the pump device is stopped, to supply liquid to the connecting pipe and perform a flushing operation for cleaning the operation inspection device.

[0014] In one aspect, the operation inspection device includes a strainer attached to the connecting pipe, and the control device executes the flushing operation to clean the strainer.

[0015] In one aspect, a method for inspecting an operation inspection device including a connecting pipe connected to a backflow prevention device, an on-off valve for opening and closing the connecting pipe, and an intermediate chamber pressure sensor for detecting a pressure in an intermediate chamber of the backflow prevention device is provided. When the on-off valve opens and closes with the connecting pipe filled with liquid, an abnormality in the on-off valve is determined based on a pressure signal detected by the intermediate chamber pressure sensor.

[0016] In one aspect, when the on-off valve is opened and closed with the connecting pipe filled with liquid, an abnormality in the on-off valve is determined based on a pressure signal detected by a discharge pipe pressure sensor connected to a discharge pipe arranged on the discharge side of the pump device and a leak detection signal detected by a water leak detector of the backflow prevention device. In one embodiment, an abnormality in at least one of the suction side pressure sensor, the intermediate chamber pressure sensor, and the discharge side pressure sensor is determined based on a comparison result between a suction side detection signal detected by a suction side pressure sensor arranged on the suction side of the backflow prevention device and an intermediate chamber side pressure signal detected by the intermediate chamber pressure sensor, and / or a comparison result between a discharge side detection signal detected by a discharge side pressure sensor arranged on the discharge side of the backflow prevention device and the intermediate chamber side pressure signal. In one aspect, the operation inspection device is equipped with a check valve arranged upstream of the on-off valve in the flow direction of liquid flowing through the connecting pipe, and when the on-off valve opens and closes with the connecting pipe filled with liquid, an abnormality in the check valve is determined based on a pressure signal detected by the intermediate chamber pressure sensor. In one aspect, when the opening and closing operation of the on-off valve is performed with the connecting pipe filled with liquid, a leak in the connecting pipe is determined based on a pressure signal detected by the intermediate chamber pressure sensor and a pressure signal detected by the discharge pipe pressure sensor.

[0017] In one aspect, a maintenance method for an operation inspection device is provided, the method comprising: a connecting pipe connected to a backflow prevention device; and an on-off valve for opening and closing the connecting pipe. When the pump device is not operating, the on-off valve is periodically opened and closed repeatedly to supply liquid to the connecting pipe, thereby performing a flushing operation for cleaning the operation inspection device.

[0018] In one aspect, the operation inspection device includes a strainer attached to the connecting pipe, and performs the flushing operation to clean the strainer. Effect of the Invention

[0019] An abnormality in the components of the operation inspection device can be determined based on the pressure signal of the intermediate chamber pressure sensor. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram showing one embodiment of a water supply device. [Diagram 2] FIG. 2 is a cross-sectional view of a backflow prevention device. [Diagram 3] FIG. [Figure 4] FIG. 2 is a diagram illustrating a configuration of a control device. [Diagram 5] FIG. 4 is a diagram showing a control device for inspecting the operation of a first check valve. [Figure 6]FIG. 11 is a diagram showing a flow of checking the operation of a first check valve by a control device. [Figure 7] FIG. 4 is a diagram showing a control device for checking the operation of a second check valve. [Figure 8] FIG. 11 is a diagram showing a flow of checking the operation of a second check valve by a control device. [Figure 9] FIG. 13 is a diagram showing a control device for checking the operation of a relief valve. [Figure 10] FIG. 13 is a diagram showing a flow of checking the operation of a relief valve by a control device. [Figure 11] FIG. 13 is a diagram showing another embodiment of the operation inspection device. [Figure 12] FIG. 13 is a diagram showing another embodiment of the operation inspection device. [Figure 13] FIG. 13 is a diagram showing another embodiment of the operation inspection device. [Figure 14] FIG. 11 is a diagram showing another embodiment of the water supply device. [Figure 15] FIG. 13 is a diagram showing another embodiment of the operation inspection device. [Figure 16] FIG. 13 is a diagram showing another embodiment of the operation inspection device. [Figure 17] FIG. 2 shows a manifold connected to a liquid supply source. [Figure 18] FIG. 2 shows a manifold connected to a liquid supply source. [Figure 19] Figure 19(a) is a table showing the sensor abnormality determination result determined based on the comparison result of the first differential pressure between the specified value and the comparison result of the second differential pressure between the specified value, and Figure 19(b) is a table showing the sensor abnormality determination result determined based on the pressure relationship between the suction side pressure, the intermediate chamber side pressure, and the discharge side pressure. [Figure 20] 20(a) and 20(b) are diagrams showing an embodiment of an operation inspection device equipped with a strainer. [Figure 21] 21(a) and 21(b) are diagrams showing another embodiment of the operation inspection device equipped with a strainer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, the same components are given the same reference numerals, and duplicated explanations will be omitted. Fig. 1 is a schematic diagram showing one embodiment of a water supply device. As shown in Fig. 1, the water supply device 1 is a device used to supply water to buildings such as office buildings and apartment buildings, and is connected to a supply source (not shown) such as a water main or a water tank via an inlet pipe 5.

[0022] The water supplying apparatus 1 comprises a pump device and a backflow prevention device 15 arranged on the suction side of the pump device. The pump device is a combination of a pump 2 and a motor 3. The water supplying apparatus 1 comprises a plurality of pumps 2 (two in this embodiment) and a plurality of motors 3 (two in this embodiment). The numbers of pumps 2 and motors 3 are not limited to this embodiment. The components of the water supplying apparatus 1 are housed in a cabinet 30.

[0023] The water supply device 1 includes a suction pipe 10 connected to the suction port of the pump 2, and a discharge pipe 8 connected to the discharge port of the pump 2. The suction pipe 10 includes a suction connection pipe 9 that connects the introduction pipe 5 and the backflow prevention device 15, and a suction header pipe 18 that connects the backflow prevention device 15 and the pump 2.

[0024] The water supply device 1 includes a suction pipe pressure sensor 101 connected to the suction connection pipe 9 (or the inlet pipe 5). The suction pipe pressure sensor 101 is configured to detect the pressure of the suction connection pipe 9 (or the inlet pipe 5).

[0025] The discharge pipe 8 includes a discharge connection pipe 27 connected to the discharge port of each pump 2, and a discharge collection pipe 34 connected to the discharge connection pipe 27. The discharge collection pipe 34 is connected to a water distribution pipe 7. The water distribution pipe 7 is connected to a water supply fixture (e.g., a faucet) arranged inside the building.

[0026] The water supply device 1 includes an inverter 21, which is an example of a variable speed means for the motor 3 as a drive source for driving the pump 2, and a control device 20 that controls the operation of the pump device. The control device 20 controls the driving of the motor 3 via the inverter 21. When the motor 3 is driven, the pump 2 increases the pressure of the conveying liquid and supplies the conveying liquid to the building. A pipe silencer 13 is connected to the inlet pipe 5 to suppress the propagation of vibrations of the pump device.

[0027] The water supply device 1 is equipped with a pressure tank 28 that stores a portion of the carrier liquid pressurized by the pump 2, and a flow rate detector (not shown) connected to the discharge pipe 8. When the pump device is not operating, the pressure in the water distribution pipe 7 is maintained by the pressure tank 28. The flow rate detector is a device that detects whether the flow rate of the carrier liquid is equal to or lower than a predetermined low flow rate (i.e., a low flow rate state).

[0028] When the flow detector detects a low water flow state, the control device 20 issues a command to the inverter 21 to temporarily increase the operating speed of the pump device, stores pressure in the pressure tank 28, and then stops the operation of the pump device (low water flow stop). On the other hand, when the pressure in the discharge pipe 8 drops to a predetermined starting pressure, the control device 20 issues a command to the inverter 21 to start the operation of the pump device.

[0029] As shown in Fig. 1, the water supply device 1 includes a discharge pipe pressure sensor 102 connected to a discharge pipe 8 arranged on the discharge side of the pump device. In the embodiment shown in Fig. 1, the discharge pipe pressure sensor 102 is connected to a water distribution pipe 7, but may be connected to a discharge manifold 34. The discharge pipe pressure sensor 102 is configured to detect the pressure of the discharge pipe 8. Based on the pressure signal detected by the discharge pipe pressure sensor 102, the control device 20 issues a command to the inverter 21 to start operation of the pump device.

[0030] Fig. 2 is a cross-sectional view of the backflow prevention device. The backflow prevention device 15 is disposed between the suction connection pipe 9 and the suction header pipe 18, and is a pressure reducing type backflow prevention device that prevents the conveyed liquid from flowing back into the introduction pipe 5. As shown in Fig. 2, the backflow prevention device 15 includes a first check valve (valve body) 43 and a second check valve (valve body) 44, a relief valve (valve body) 45 disposed in an intermediate chamber 46 formed between the first check valve 43 and the second check valve 44, and a valve box 48 that houses the check valves 43, 44 and the relief valve 45.

[0031] The backflow prevention device 15 has an outlet 47 formed in the lower part of the valve box 48. The water supply device 1 includes a water leakage detector 49 that detects liquid passing through the outlet 47, and a water leakage receiver 40 arranged below the outlet 47. In this embodiment, the water leakage detector 49 is attached to the backflow prevention device 15, but in one embodiment, the water leakage detector 49 may be attached to the water leakage receiver 40.

[0032] When the second check valve 44 fails, the carrier liquid flowing through the suction pipe 10 passes through the second check valve 44 and flows into the intermediate chamber 46. The relief valve 45 opens due to the pressure of the carrier liquid that has flowed into the intermediate chamber 46, and as a result, the carrier liquid flows out through the outlet 47. In this way, the backflow prevention device 15 can prevent the carrier liquid from flowing back into the introduction pipe 5.

[0033] The leak receiver 40 receives the carrier liquid leaked from the backflow prevention device 15. The carrier liquid received in the leak receiver 40 is discharged to the outside of the water supply device 1. The control device 20 is electrically connected to the water leakage detector 49. Therefore, the control device 20 can determine the passage of the carrier liquid through the discharge port 47 based on the leakage detection signal detected by the water leakage detector 49.

[0034] In this embodiment, the control device 20 is configured to determine leakage of the conveyed liquid from the discharge port 47 based on a leakage detection signal sent from the leakage detector 49, but in one embodiment, the control device 20 may determine leakage (i.e., operation of the relief valve 45) based on image data sent from a camera (not shown). In one embodiment, the control device 20 may determine leakage based on an opening detection signal sent from an opening detection sensor (e.g., a displacement sensor, a linear sensor) that detects the opening of the relief valve 45.

[0035] As shown in Figures 1 and 2, the water supply device 1 is equipped with an intermediate chamber pressure sensor 55 that detects the pressure in the intermediate chamber 46, a suction side pressure sensor 41 arranged on the suction side of the backflow prevention device 15, and a discharge side pressure sensor 42 arranged on the discharge side of the backflow prevention device 15.

[0036] The suction side pressure sensor 41 is configured to detect the pressure in the suction side region 56 of the backflow prevention device 15. In this embodiment, the suction side pressure sensor 41 is attached to the backflow prevention device 15, but in one embodiment, the suction side pressure sensor 41 may be attached to the suction connecting pipe 9. The suction side pressure sensor 41 and the intermediate chamber pressure sensor 55 are disposed on both sides of the first check valve 43.

[0037] In one embodiment, a suction pipe pressure sensor 101 (see FIG. 1) may be arranged instead of the suction side pressure sensor 41, or both the suction side pressure sensor 41 and the suction pipe pressure sensor 101 may be arranged.

[0038] Although details will be described later, the control device 20 determines an abnormality in the backflow prevention device 15 based on the pressure detected by the suction side pressure sensor 41. In one embodiment, the control device 20 may control the pump device based on the pressure detected by the suction side pressure sensor 41. In one embodiment, the control device 20 may determine an abnormality in the drop in inflow pressure based on the pressure detected by the suction side pressure sensor 41.

[0039] The discharge side pressure sensor 42 is configured to detect the pressure in the discharge side region 57 of the backflow prevention device 15. In this embodiment, the discharge side pressure sensor 42 is attached to the backflow prevention device 15, but in one embodiment, the discharge side pressure sensor 42 may be attached to the suction header pipe 18. The discharge side pressure sensor 42 and the intermediate chamber pressure sensor 55 are disposed on both sides of the second check valve 44. The intermediate chamber 46 is formed between the suction side region 56 and the discharge side region 57.

[0040] Fig. 3 is a diagram showing an operation inspection device. As shown in Fig. 3, the water supply device 1 is provided with an operation inspection device 50 for inspecting the operation of the relief valve 45 of the backflow prevention device 15. A method for inspecting the operation of the relief valve 45 will be described later. The operation inspection device 50 is provided with an intermediate chamber pressure sensor 55, a connecting pipe 51 that connects the discharge side of the pump device (more specifically, the pump 2) and the intermediate chamber 46, and an opening / closing valve 53 that opens and closes the connecting pipe 51.

[0041] One end of the connecting pipe 51 is connected to the discharge pipe 8, and the other end is connected to the backflow prevention device 15. A part of the pressurized carrier liquid flowing through the discharge pipe 8 is returned to the backflow prevention device 15 through the connecting pipe 51. The intermediate chamber pressure sensor 55 is connected to the connecting pipe 51, and is disposed downstream of the on-off valve 53 in the flow direction of the carrier liquid. In this embodiment, the on-off valve 53 is a solenoid valve. The on-off valve 53 is not limited to a solenoid valve as long as it can open and close the connecting pipe 51.

[0042] The operation inspection device 50 includes an air vent valve 52 attached to the upper end of the connecting pipe 51, and a flow rate regulator 54 connected to the connecting pipe 51. The air vent valve 52 is configured to exhaust air from within the connecting pipe 51, and the flow rate regulator 54 is configured to regulate the flow rate of the carrier liquid passing through the connecting pipe 51.

[0043] In this embodiment, the intermediate chamber pressure sensor 55 is disposed downstream of the flow rate adjustment device 54 in the flow direction of the carrier liquid. In other words, the intermediate chamber pressure sensor 55 is disposed closer to the backflow prevention device 15 than the flow rate adjustment device 54. With this arrangement, the intermediate chamber pressure sensor 55 can detect the pressure in the intermediate chamber 46 without being affected by pressure loss. The air vent valve 52 may be omitted depending on the structure of the water supply apparatus 1.

[0044] The flow rate adjustment device 54 adjusts the flow rate of the carrier liquid introduced into the intermediate chamber 46 through the connecting pipe 51. To check the operation of the relief valve 45, the flow rate adjustment device 54 adjusts the flow rate of the carrier liquid so that the first check valve 43 is closed and the relief valve 45 is opened by the pressure of the carrier liquid. An example of the flow rate adjustment device 54 is a flow rate adjustment valve or an orifice. In one embodiment, when the opening / closing valve 53 also has the function of the flow rate adjustment device 54, the operation check device 50 may omit the flow rate adjustment device 54. In this case, the opening / closing valve 53 may be an electric valve.

[0045] Fig. 4 is a diagram showing the configuration of the control device. As shown in Fig. 4, the on-off valve 53, the suction side pressure sensor 41, the discharge side pressure sensor 42, the intermediate chamber pressure sensor 55, and the water leakage detector 49 are electrically connected to the control device 20. Detection signals detected by these pressure sensors 41, 42, 55 and the water leakage detector 49 are sent to the control device 20.

[0046] Similarly, the pressure sensors 101, 102 are electrically connected to the control device 20, and detection signals detected by these pressure sensors 101, 102 are sent to the control device 20. Hereinafter, in this specification, the control device 20 that operates based on signals from the sensors 41, 42, 55 and the water leak detector 49 will be described.

[0047] The control device 20 comprises a board 60 including a display board and a control board, and an option board 61 for performing remote inspection of the backflow prevention device 15. The board 60 and the option board 61 are electrically connected. The display board constituting the board 60 is configured to externally display information related to the water supply device 1, and the control board constituting the board 60 is configured to control the operation of the components of the water supply device 1.

[0048] The option board 61 is configured to receive signals from the sensors 41, 42, and 55 and the water leak detector 49, and the board 60 is configured to inspect the backflow prevention device 15 based on the signals received by the option board 61. In one embodiment, the board 60 may include the option board 61. More specifically, the board 60 may receive signals from the sensors 41, 42, and 55 and the water leak detector 49, and inspect the backflow prevention device 15. In this case, the option board 61 may be omitted.

[0049] As shown in FIG. 4, the control device 20 is electrically connected to external devices (e.g., a host device 63, an external display / operation device 64, etc.) of the water supply device 1. The water supply device 1 and the external devices constitute a water supply system. Examples of the host device 63 include a tablet computer and a notebook computer. The host device 63 may be a remote monitoring server (or cloud) that provides various network services to the control device 20. The external device is capable of wireless communication with the control device 20 via communication means such as Bluetooth communication, wireless LAN communication, and NFC communication. Below, a method of inspecting the backflow prevention device 15 using the control device 20 will be described with reference to the drawings.

[0050] Fig. 5 is a diagram showing a control device that performs an operation check of the first check valve. Fig. 6 is a diagram showing a flow of the operation check of the first check valve by the control device. The control device 20 is configured to determine an abnormality of the first check valve 43 based on the pressure difference between the pressures detected by the suction side pressure sensor 41 and the intermediate chamber pressure sensor 55 arranged on both sides of the first check valve 43.

[0051] 6, the control device 20 starts the inspection operation of the backflow prevention device 15 on the condition that an inspection start condition is satisfied. The inspection start condition requires that when the flow rate of the transport liquid is in a low-flow state, the control device 20 performs a low-flow stop operation and the operation of the pump device is stopped.

[0052] When the inspection start condition is met, the control device 20 starts the inspection operation of the backflow prevention device 15 based on a predetermined inspection execution timing. In one embodiment, as the inspection execution timing, the control device 20 may perform the inspection operation of the backflow prevention device 15 upon the passage of a time (e.g., once a month) that is preset by a CPU driving clock or a clock IC mounted on the board 60 (or the option board 61).

[0053] If the inspection start condition is not satisfied even after the above-mentioned predetermined set time has elapsed, the control device 20 cannot perform the inspection operation of the backflow prevention device 15. Therefore, if the inspection operation of the backflow prevention device 15 is not performed immediately even after the predetermined set time has elapsed, the control device 20 may calculate a time period during which the pump device will be stopped for a long period of time based on the operation history of the water supply device 1, and perform the inspection operation of the backflow prevention device 15 during this time period.

[0054] In one embodiment, the control device 20 may perform an inspection operation of the backflow prevention device 15 based on a command from a higher-level device 63, or may perform the inspection operation based on a user's operation of the board 60 (or the optional board 61). The user may issue a command to the control device 20 by operating the external display / operation device 64.

[0055] 6, the control device 20 acquires a pressure signal detected by the suction-side pressure sensor 41 (i.e., inflow pressure data) and a pressure signal detected by the intermediate chamber pressure sensor 55 (i.e., intermediate chamber pressure data). Thereafter, the control device 20 determines whether the pump device is stopped at a low water flow rate (see step S102). If the pump device is not stopped at a low water flow rate (see "No" in step S102), for example, if the operation of the pump device is resumed while the inspection operation of the backflow prevention device 15 is being performed, the control device 20 stops the inspection operation of the backflow prevention device 15.

[0056] If the pump device is in the low water flow stopped state (see "Yes" in step S102), the control device 20 judges whether a predetermined pressure monitoring period (e.g., 5 to 10 seconds) has elapsed (see step S104). If the pressure monitoring period has not elapsed (see "No" in step S104), the control device 20 executes step S102 again.

[0057] The control device 20 calculates the pressure difference (first pressure difference) at the start of pressure monitoring based on the pressures acquired in step S101 (i.e., the pressure in the suction side region 56 and the pressure in the intermediate chamber 46). During this pressure monitoring period, the control device 20 monitors in real time whether the first pressure difference has changed. If the first pressure difference has changed, the control device 20 executes step S102 again.

[0058] When the pressure monitoring period has elapsed (see "Yes" in step S104), the control device 20 acquires the pressure signal detected by the suction side pressure sensor 41 and the pressure signal detected by the intermediate chamber pressure sensor 55 (see step S105). The control device 20 calculates the current pressure difference (second pressure difference) based on the pressures acquired in step S105 (i.e., the pressure in the suction side area 56 and the pressure in the intermediate chamber 46) (see step S106).

[0059] The control device 20 monitors the amount of change between the first pressure difference and the second pressure difference, and determines whether or not the amount of change in the differential pressure is within a predetermined range (see step S107). If the amount of change in the differential pressure is within the predetermined range (see "Yes" in step S107), the control device 20 determines that the first check valve 43 operates normally (see step S108), and ends the inspection operation of the backflow prevention device 15.

[0060] If the amount of change in differential pressure is outside the specified range (see "No" in step S107), the control device 20 determines that the first check valve 43 is abnormal (see step S109). Normally, when the first check valve 43 is operating normally, the pressure in the suction side region 56 and the pressure in the intermediate chamber 46 are maintained by the first check valve 43. Therefore, when the amount of change in differential pressure exceeds the specified range, the first check valve 43 is not operating normally.

[0061] When the control device 20 determines that the first check valve 43 is abnormal, the control device 20 may output an alarm to the higher-level device 63 (and / or the external display / operation device 64) to notify the user of the abnormality of the first check valve 43. In one embodiment, the control device 20 may display the abnormality of the first check valve 43 on the board 60, or may output a contact signal. The water supply device 1 plays a very important role in supporting life infrastructure. Therefore, even if the control device 20 determines that the first check valve 43 is abnormal, the control device 20 may continue to operate the pump device.

[0062] According to this embodiment, since the water supply apparatus 1 is equipped with the intermediate chamber pressure sensor 55, an operator (or user) can inspect the backflow prevention device 15 based on the pressure detected by the intermediate chamber pressure sensor 55. As a result, the operator can omit the troublesome task of directly accessing the water supply apparatus 1 and connecting a test kit to the backflow prevention device 15.

[0063] Furthermore, according to this embodiment, the control device 20 performs an inspection operation of the backflow prevention device 15 when the operation of the pump device is stopped (more specifically, when the pump device is stopped at a small water volume). Therefore, in order to inspect the backflow prevention device 15, it is not necessary to take the trouble of stopping the operation of the water supply device 1 and continuing the water outage state.

[0064] In one embodiment, the control device 20 may be included in an external device. In this case, the control device 20 of the external device can perform the inspection operation of the backflow prevention device 15 (from the start of inspection to the determination of the inspection result) from outside the water supply apparatus 1. In this way, the water supply system may perform the inspection operation of the backflow prevention device 15 through the control device 20 arranged inside the water supply apparatus 1, or may perform the inspection operation of the backflow prevention device 15 through the control device 20 arranged outside the water supply apparatus 1 (more specifically, the control device 20 arranged inside the external device).

[0065] In one embodiment, the water supply system may include a control device 20 arranged inside the water supply device 1 and a new control device arranged inside the external device, which is different from the control device 20. The new control device may have a similar configuration to the control device 20.

[0066] In the above-described embodiment, the configuration of the control device 20 that performs the inspection operation of the backflow prevention device 15 has been described, but the control device 20 may also be equipped with a memory device 62 that stores a program for performing the inspection operation of the backflow prevention device 15, and a processing device 65 that performs calculations according to the program stored in the memory device 62 (see Figure 4).

[0067] The storage device 62 includes a main storage device (e.g., random access memory) accessible by the processing device 65, and an auxiliary storage device (e.g., a hard disk drive or a solid-state drive) for storing data and programs. The processing device 65 includes a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit).

[0068] This program includes a command to calculate a first pressure difference at the start of pressure monitoring and a current second pressure difference based on the pressures detected by the suction side pressure sensor 41 and the intermediate chamber pressure sensor 55, and to determine that there is an abnormality in the first check valve 43 if the amount of change between the first pressure difference and the second pressure difference is outside a predetermined specified range. Although a detailed description will be omitted, in the embodiment described below as well, the storage device 62 stores a program including a command to determine that there is an abnormality in the second check valve 44 and the relief valve 45.

[0069] The above program is recorded in a computer-readable recording medium, which is a non-transitory tangible object, and is provided to the control device 20 via the recording medium. Alternatively, the program may be input to the control device 20 from a communication device (not shown) via a communication network such as the Internet or a local area network.

[0070] Fig. 7 is a diagram showing a control device that inspects the operation of the second check valve. Fig. 8 is a diagram showing a flow of inspecting the operation of the second check valve by the control device. The control device 20 is configured to determine an abnormality in the second check valve 44 based on the pressure difference between the pressures detected by the intermediate chamber pressure sensor 55 and the discharge side pressure sensor 42 arranged on both sides of the second check valve 44.

[0071] 8, on condition that the inspection start condition is satisfied, the control device 20 acquires a pressure signal (i.e., discharge pressure data) detected by the discharge side pressure sensor 42 and a pressure signal (i.e., intermediate chamber pressure data) detected by the intermediate chamber pressure sensor 55. Thereafter, the control device 20 executes steps similar to steps S102 to S104 described above (see steps S202 to S204).

[0072] 8, the control device 20 acquires a pressure signal detected by the discharge side pressure sensor 42 and a pressure signal detected by the intermediate chamber pressure sensor 55. The control device 20 calculates a pressure difference (first pressure difference) at the start of pressure monitoring based on the pressures acquired in step S201 (i.e., the pressure of the discharge side area 57 and the pressure of the intermediate chamber 46). As shown in step S206, the control device 20 calculates a current pressure difference (second pressure difference) based on the pressures acquired in step S205 (i.e., the pressure of the discharge side area 57 and the pressure of the intermediate chamber 46).

[0073] The control device 20 monitors the amount of change between the first pressure difference and the second pressure difference, and determines whether or not this amount of change in differential pressure is within a predetermined range (see step S207). If the amount of change in differential pressure is within the specified range (see "Yes" in step S207), the control device 20 determines that the second check valve 44 is normal (see step S208), and ends the inspection operation of the backflow prevention device 15.

[0074] If the amount of change in differential pressure is outside the specified range (see "No" in step S207), the control device 20 determines that the second check valve 44 is abnormal (see step S209). In this case, similar to the embodiment described above, the control device 20 may output an alarm notifying the user of the abnormality of the second check valve 44.

[0075] As in the above-described embodiment, the storage device 62 may store a program including instructions for executing steps similar to those in the flowchart shown in Fig. 8. The processing device 65 executes an inspection operation program for the backflow prevention device 15 in accordance with the program stored in the storage device 62.

[0076] Fig. 9 is a diagram showing a control device that inspects the operation of the relief valve. Fig. 10 is a diagram showing a flow of inspecting the operation of the relief valve by the control device. The control device 20 is configured to determine an abnormality in the relief valve 45 based on a water leakage detection signal detected by the water leakage detector 49 and a pressure difference between the pressures detected by the suction side pressure sensor 41 and the intermediate chamber pressure sensor 55.

[0077] 9 and 10, the inspection start condition is that the discharge pressure of the discharge side region 57 is greater than the inflow pressure of the suction side region 56. After starting the inspection operation, the control device 20 stops the inspection operation if the fluctuation of the inflow pressure is equal to or greater than a predetermined allowable range.

[0078] 10, the control device 20 operates the on-off valve 53 to open the connecting pipe 51 (i.e., turns the on-off valve 53 to the ON state) on the condition that the inspection start condition is met. Then, the carrier liquid pressurized by the pump 2 is introduced into the intermediate chamber 46 of the backflow prevention device 15 through the connecting pipe 51. By the introduction of the carrier liquid, the first check valve 43 (and the second check valve 44) is closed and the relief valve 45 is opened.

[0079] The control device 20 judges whether the pump device is stopped at a low water flow rate (see step S302), and if the pump device is not stopped at a low water flow rate (see "No" in step S302), it operates the on-off valve 53 to close the connecting pipe 51 (i.e., turns the on-off valve 53 to the OFF state). In this way, the control device 20 stops the inspection operation of the backflow prevention device 15.

[0080] When the pump device is stopped at a low water flow rate (see "Yes" in step S302), the control device 20 judges whether the water leakage detector 49 detects a water leakage within a predetermined waiting time (see step S304). When a water leakage is not detected within this waiting time (see "No" in step S304), the control device 20 closes the on-off valve 53 (step S305) and determines that the relief valve 45 is abnormal (see step S306).

[0081] When the predetermined waiting time has elapsed (see "Yes" in step S304), the control device 20 judges whether or not the water leakage detector 49 has detected a water leakage (see step S307). When no water leakage is detected (see "No" in step S307), the control device 20 repeats steps S302 and S304. When a water leakage is detected (see "Yes" in step S307), the control device 20 acquires a pressure signal detected by the suction side pressure sensor 41 and a pressure signal detected by the intermediate chamber pressure sensor 55 (see step S308).

[0082] The control device 20 calculates the current pressure difference based on the pressures acquired in step S308 (i.e., the pressure in the suction side region 56 and the pressure in the intermediate chamber 46) (see step S309). After that, the control device 20 closes the on-off valve 53 (see step S310) and compares the current pressure difference with a predetermined reference value (see step S311). This reference value is an index value that indicates that the relief valve 45 is normally open and the first check valve 43 is normally closed.

[0083] If the current pressure difference is equal to or less than the reference value (see "No" in step S311), the control device 20 determines that the relief valve 45 is abnormal (see step S306). If the current pressure difference is greater than the reference value (see "Yes" in step S311), the control device 20 determines that the relief valve 45 is operating normally (see step S312), and ends the inspection operation of the backflow prevention device 15.

[0084] The storage device 62 may store a program including instructions for executing steps similar to those in the flowchart shown in Fig. 10. The processing device 65 executes an inspection operation program for the backflow prevention device 15 in accordance with the program stored in the storage device 62.

[0085] The control device 20 determines whether the backflow prevention device 15 is abnormal based on the determination criteria shown in Figures 6, 8, and 10. However, there is a possibility that the control device 20 may determine whether the backflow prevention device 15 is abnormal due to the influence of a pressure error or a temporary abnormality. Therefore, in order to reliably determine (confirm) the abnormality of the backflow prevention device 15, the control device 20 may perform a retry operation to confirm the abnormality of the backflow prevention device 15 after determining that the backflow prevention device 15 is abnormal.

[0086] The number of retry operations is not particularly limited, and the control device 20 may perform the retry operation at least once. The retry operation is executed when the next inspection start condition is satisfied after the control device 20 determines that the backflow prevention device 15 is abnormal.

[0087] When the control device 20 again determines (confirms) an abnormality in the backflow prevention device 15 by the retry operation, the control device 20 may output an abnormality signal to an external device (such as the higher-level device 63 or the external display / operation device 64). Even if the control device 20 determines that the backflow prevention device 15 is abnormal, the control device 20 may continue to operate the pump device.

[0088] The inspection operation of the backflow prevention device 15 performed by the control device 20 may be stored in the storage device 62 or in the memory of the host device 63. For example, if the control device 20 is equipped with a clock IC, the inspection result and the time when the inspection operation was performed are stored in the storage device 62. If the control device 20 is not equipped with a clock IC, the inspection result and the elapsed time from power input to the control device 20 are stored in the storage device 62. When the inspection operation of the backflow prevention device 15 is performed, the time obtained from the host device 63 may be stored in the storage device 62.

[0089] In the above embodiment, the method of inspecting the backflow prevention device 15 by the control device 20 has been described, but the method of inspecting the backflow prevention device 15 may be directly performed by an operator. In this case, the operator performs the inspection method based on the same steps as those in the above-mentioned flow charts (see FIGS. 6, 8, and 10).

[0090] The control device 20 may determine that the on-off valve 53 has failed. When determining that the on-off valve 53 has failed, the control device 20 outputs a failure signal of the on-off valve 53 to the higher-level device 63. In one embodiment, the control device 20 may display the failure of the on-off valve 53 on the board 60, or may output the failure via a contact. In one embodiment, the control device 20 may output the failure to the external display / operation device 64 via communication.

[0091] When the operation of the pump device is stopped, the control device 20 determines that the on-off valve 53 remains in the ON state and is at fault if a predetermined failure determination condition is satisfied. In this embodiment, the failure determination condition may be a first failure determination condition and a second failure determination condition.

[0092] The first fault determination condition is a condition in which a water leakage signal is received from the water leakage detector 49 despite a command being issued to the on-off valve 53 to close the connecting pipe 51. The second fault determination condition is a condition in which there is no change in the pressure signal from the intermediate chamber pressure sensor 55 when the on-off valve 53 outputs an ON signal, and in the pressure signal from the intermediate chamber pressure sensor 55 when the on-off valve 53 outputs an OFF signal. When the first fault determination condition and the second fault determination condition are satisfied, the control device 20 determines that the on-off valve 53 does not change to an OFF state and remains in an ON state.

[0093] When a predetermined failure determination condition is satisfied, the control device 20 determines that a failure occurs in the on-off valve 53 while the on-off valve 53 remains in the OFF state. In this embodiment, the failure determination condition may include a first failure determination condition and a second failure determination condition.

[0094] The first fault determination condition is a condition that no water leakage signal is received from the water leakage detector 49 during an inspection operation of the backflow prevention device 15. The second fault determination condition is a condition that there is no change in the pressure signal from the intermediate chamber pressure sensor 55 when the on-off valve 53 outputs an ON signal, and in the pressure signal from the intermediate chamber pressure sensor 55 when the on-off valve 53 outputs an OFF signal. When the first fault determination condition and the second fault determination condition are satisfied, the control device 20 determines that the on-off valve 53 does not become the ON state and remains in the OFF state.

[0095] FIG. 11 is a diagram showing another embodiment of the operation inspection device. As shown in FIG. 11, the operation inspection device 50 may include flow rate adjustment devices 67, 68 arranged upstream of the on-off valve 53 in the flow direction of the carrier liquid flowing through the connecting pipe 51. The flow rate adjustment devices 67, 68 are arranged in this order in the flow direction of the carrier liquid. Examples of the flow rate adjustment device 68 include an orifice, a throttle pipe, a solenoid valve, or a throttle valve. In one embodiment, the flow rate adjustment devices 54, 67 may be omitted. In this embodiment, too, the intermediate chamber pressure sensor 55 arranged closer to the backflow prevention device 15 than the on-off valve 53 can detect the pressure of the intermediate chamber 46 without being affected by pressure loss.

[0096] Fig. 12 is a diagram showing another embodiment of the operation inspection device. As shown in Fig. 12, the operation inspection device 50 includes a flexible pipe 70A connected to the discharge pipe 8 and a flexible pipe 70B connected to the backflow prevention device 15.

[0097] Each of the flexible pipes 70A, 70B is a flexible pipe or a tube pipe, and the flexible pipes 70A, 70B form a part of the connecting pipe 51. With such a configuration, each of the flexible pipes 70A, 70B can prevent vibrations of the pump device from being transmitted to the on-off valve 53 and the intermediate chamber pressure sensor 55.

[0098] Furthermore, the operation inspection device 50 equipped with the flexible pipes 70A, 70B can improve the degree of freedom of its overall layout. Therefore, the components of the water supply device 1 can be arranged in various positions without being restricted by the layout. As a result, the water supply device 1 can be made smaller overall.

[0099] Fig. 13 is a diagram showing another embodiment of the operation inspection device. As shown in Fig. 13, the operation inspection device 50 includes an on-off valve 75 that connects the pressure tank 28 and the connecting pipe 51. In this embodiment, the on-off valve 75 is a three-way solenoid valve electrically connected to the control device 20.

[0100] The on-off valve 75 has the functions of both the on-off valve 29 (see FIG. 1) connected to the pressure tank 28 and the on-off valve 53 (see FIG. 1). In this embodiment, the control device 20 can open and close the connecting pipe 51 and the pressure tank 28 by operating the on-off valve 75. More specifically, the control device 20 operates the on-off valve 75 to connect the upstream side and the downstream side of the connecting pipe 51 while closing the pressure tank 28. The control device 20 operates the on-off valve 75 to connect the pressure tank 28 and the upstream side of the connecting pipe 51 while closing the downstream side of the connecting pipe 51. The control device 20 operates the on-off valve 75 to connect the pressure tank 28 and the downstream side of the connecting pipe 51 while closing the upstream side of the connecting pipe 51.

[0101] In this embodiment, by providing on-off valve 75 as a three-way valve, the number of parts of water supply apparatus 1 can be reduced, and as a result, the cost of water supply apparatus 1 can be reduced.

[0102] Fig. 14 is a diagram showing another embodiment of the water supply apparatus. In the embodiment shown in Fig. 14, the water supply apparatus 1 is provided with a suction side differential pressure sensor 80 and a discharge side differential pressure sensor 81 instead of the suction side pressure sensor 41, the discharge side pressure sensor 42, and the intermediate chamber pressure sensor 55.

[0103] The suction side differential pressure sensor 80 is configured to detect the differential pressure between the pressure in the suction side area 56 and the pressure in the intermediate chamber 46. The discharge side differential pressure sensor 81 is configured to detect the differential pressure between the pressure in the discharge side area 57 and the pressure in the intermediate chamber 46. The control device 20 is configured to determine an abnormality in the first check valve 43 based on the pressure difference detected by the suction side differential pressure sensor 80. In this case, the water supply device 1 does not necessarily have to be equipped with the discharge side differential pressure sensor 81.

[0104] Similarly, the control device 20 is configured to determine an abnormality in the second check valve 44 based on the pressure difference detected by the discharge side differential pressure sensor 81. Furthermore, the control device 20 is configured to determine an abnormality in the relief valve 45 based on the leakage detection signal detected by the leakage detector 49 and the pressure difference detected by the discharge side differential pressure sensor 81. When determining an abnormality in the second check valve 44 or the relief valve 45, the water supply device 1 does not necessarily need to be equipped with the suction side differential pressure sensor 80.

[0105] Fig. 15 is a diagram showing another embodiment of the operation inspection device. As shown in Fig. 15, the operation inspection device 50 may include a check valve 90 arranged upstream of the flow rate adjustment device 68 in the flow direction of the carrier liquid flowing through the connecting pipe 51.

[0106] The check valve 90 is configured to restrict the flow of liquid from the discharge pipe 8 to the backflow prevention device 15. Depending on the operating conditions of the water supply apparatus 1, pressure from the direction opposite to normal may act on the flow rate adjustment device 68 (and / or the on-off valve 53), which may cause the flow rate adjustment device 68 to open. The check valve 90 serves to maintain pressure while the pump 2 is not operating when the discharge pipe 8 is open. Therefore, it is possible to prevent back pressure from acting on the flow rate adjustment device 68 (and / or the on-off valve 53).

[0107] Fig. 16 is a diagram showing another embodiment of the operation inspection device. As shown in Fig. 16, the operation inspection device 50 may include a pressure pump 91 connected to the connecting pipe 51. The pressure pump 91 is disposed upstream of the flow rate control device 54 (and the intermediate chamber pressure sensor 55) in the flow direction of the carrier liquid flowing through the connecting pipe 51. In the embodiment shown in Fig. 16, an on-off valve 92 is connected to the connecting pipe 51, but the on-off valve 92 may be omitted.

[0108] The control device 20 is electrically connected to the pressure pump 91 and controls the operation of the pressure pump 91. The control device 20 may operate the pressure pump 91 as an auxiliary during an inspection operation of the backflow prevention device 15.

[0109] According to the embodiment described above, by providing the operation check device 50, it is possible to omit the troublesome task of connecting the test kit to the backflow prevention device 15. However, the operation check device 50 includes various components (e.g., the on-off valve 53, the intermediate chamber pressure sensor 55). Therefore, if an abnormality (failure) occurs in these components, the operation check device 50 may not operate normally.

[0110] In this case, the operation inspection device 50 may not be able to properly inspect the backflow prevention device 15, and may erroneously determine the inspection result of the backflow prevention device 15. Therefore, in the embodiment shown below, a method (configuration) for determining an abnormality in the operation inspection device 50 will be described.

[0111] 17 and 18 are diagrams showing a connecting pipe connected to a liquid supply source. In the above-mentioned embodiment, the connecting pipe 51 connected to the discharge pipe 8 and the backflow prevention device 15 has been described, but as long as liquid can be supplied to the backflow prevention device 15 through the connecting pipe 51, the connecting pipe 51 does not necessarily have to be connected to the discharge pipe 8.

[0112] 17 and 18, one end of the connecting pipe 51 may be connected to a liquid supply source 120. The liquid supply source 120 may be a device disposed outside the water supply apparatus 1 for supplying liquid to the backflow prevention device 15 through the connecting pipe 51.

[0113] In one embodiment, the liquid supply source 120 is a combination of a liquid supply pipe (not shown) and a liquid feed pump (not shown). In one embodiment, the liquid supply source 120 may be a reservoir tank that stores pressurized liquid.

[0114] The embodiment shown in Fig. 17 basically has the same configuration as the embodiment shown in Fig. 3. The embodiment shown in Fig. 18 basically has the same configuration as the embodiment shown in Fig. 15. Although not shown, one end of the connecting pipe 51 may be connected to the liquid supply source 120 in the embodiments shown in Figs. 1 to 16 as well.

[0115] The following describes a configuration (method) for determining whether or not there is an abnormality in the on-off valve 53. When one end of the connecting pipe 51 is connected to the discharge pipe 8, the pressure in the discharge pipe 8 is higher than the pressure in the backflow prevention device 15, so that the liquid in the discharge pipe 8 is supplied to the backflow prevention device 15 through the connecting pipe 51.

[0116] Similarly, even when one end of the connecting pipe 51 is connected to the liquid supply source 120, the pressure difference between the liquid supply source 120 and the backflow prevention device 15 causes liquid to be supplied to the backflow prevention device 15 through the connecting pipe 51.

[0117] For example, when the control device 20 issues an "open" command to the on-off valve 53, normally, liquid passes through the connecting pipe 51 and the pressure signal detected by the intermediate chamber pressure sensor 55 changes (more specifically, becomes higher).

[0118] However, if an abnormality occurs in the on-off valve 53, even if the control device 20 issues an "open" command to the on-off valve 53, the on-off valve 53 will not open and the connecting pipe 51 will remain closed. Therefore, the pressure signal detected by the intermediate chamber pressure sensor 55 will not change.

[0119] In this way, the intermediate chamber pressure sensor 55 is configured to detect a pressure signal as an index for determining whether or not there is an abnormality in the on-off valve 53 when the on-off valve 53 is opening or closing with the connecting pipe 51 filled with liquid.

[0120] When the pressure signal of the intermediate chamber pressure sensor 55 does not change even if the control device 20 issues an "open" command to the on-off valve 53, the control device 20 determines (judges) that an abnormality has occurred in the on-off valve 53. In other words, the control device 20 is configured to execute the opening and closing operation of the on-off valve 53 while liquid is being supplied to the connecting pipe 51, and to determine that the on-off valve 53 is abnormal based on the pressure signal detected by the intermediate chamber pressure sensor 55.

[0121] Assume that the on-off valve 53 remains open and cannot be closed. In this case, even if the control device 20 issues a "close" command to the on-off valve 53, the on-off valve 53 remains open and the connecting pipe 51 is not closed. Then, when one end of the connecting pipe 51 is connected to the discharge pipe 8, the liquid held in the pressure tank 28 is supplied to the backflow prevention device 15 through the connecting pipe 51 while the pump device is not operating. When the liquid is supplied from the pressure tank 28, the pressure in the discharge pipe 8 (more specifically, the water distribution pipe 7) gradually decreases. As a result, the pressure signal detected by the discharge pipe pressure sensor 102 decreases.

[0122] When the liquid held in the pressure tank 28 is supplied to the backflow prevention device 15 through the connecting pipe 51, the liquid is discharged from the outlet 47 of the backflow prevention device 15. As a result, the water leak detector 49 detects a water leak detection signal.

[0123] In this way, when the on-off valve 53 remains open even after a "close" command is issued to the on-off valve 53, the detection signal of the discharge pipe pressure sensor 102 and the detection signal of the water leakage detector 49 change. Therefore, the control device 20 is configured to determine an abnormality in the on-off valve 53 based on the pressure signal detected by the discharge pipe pressure sensor 102 (see FIG. 1) connected to the discharge pipe 8 and the water leakage detection signal detected by the water leakage detector 49 (see FIG. 2) of the backflow prevention device 15 during the opening and closing operation of the on-off valve 53 with the connecting pipe 51 filled with liquid.

[0124] When the operation of the pump device is started, the relief valve 45 is closed, and the water leakage detection signal detected by the water leakage detector 49 is cancelled. Therefore, the control device 20 may determine that the on-off valve 53 is abnormal by satisfying the following conditions (1) to (3). Condition (1): When the pump device is not operating, the water leak detector 49 detects a water leak detection signal. Condition (2): When the pump device is not operating, the pressure signal detected by the discharge pipe pressure sensor 102 decreases. Condition (3): After the pump device starts operating, the leak detection signal detected by the leak detector 49 is released.

[0125] If the on-off valve 53 does not open even when an "open" command is issued to the on-off valve 53, there is a risk that foreign matter has become clogged in the on-off valve 53. In addition, if liquid remains in the connecting pipe 51 for a long period of time, there is a risk that foreign matter will become clogged in the on-off valve 53 (and / or the connecting pipe 51). Therefore, the control device 20 may periodically execute a flushing operation for cleaning the operation inspection device 50.

[0126] While the pump device is not operating, the control device 20 periodically (i.e., based on a predetermined flushing operation execution timing) repeatedly opens and closes the on-off valve 53 to supply liquid to the connecting pipe 51. More specifically, the control device 20 opens the on-off valve 53 (i.e., issues an "open" command to the on-off valve 53) to forcefully supply liquid to the connecting pipe 51.

[0127] The liquid supplied to the connecting pipe 51 pushes out the liquid remaining in the connecting pipe 51, and cleans the operation inspection device 50 (particularly the connecting pipe 51 and the on-off valve 53). At this time, the relief valve 45 opens, and the remaining liquid is discharged. After a predetermined time has elapsed since the on-off valve 53 was opened, the control device 20 closes the on-off valve 53 (i.e., issues a "close" command to the on-off valve 53). In this way, the control device 20 performs a flushing operation by periodically repeating the opening and closing operation of the on-off valve 53, and can prevent the connecting pipe 51 and / or the on-off valve 53 from becoming clogged with foreign matter.

[0128] Based on a predetermined flushing operation execution timing, the control device 20 starts the flushing operation of the operation inspection device 50. The flushing operation is an operation for passing a liquid forcefully through the operation inspection device 50 (particularly, the connecting pipe 51 and the on-off valve 53).

[0129] In one embodiment, the control device 20 may perform the flushing operation on the condition that a preset time (e.g., once a week) has elapsed by a CPU driving clock or a clock IC mounted on the board 60 (or the option board 61). The flushing operation is performed at a shorter cycle than the above-mentioned inspection execution cycle (e.g., once a month).

[0130] The following describes the configuration (method) for determining abnormality in the intermediate chamber pressure sensor 55, the suction side pressure sensor 41, and the discharge side pressure sensor 42. The intermediate chamber pressure sensor 55 is configured to detect a pressure signal (intermediate chamber side pressure signal) as an index for determining abnormality of the intermediate chamber pressure sensor 55, which is obtained from the result of comparison with the pressure signal (suction side pressure signal) detected by the suction side pressure sensor 41 and / or the result of comparison with the pressure signal (discharge side pressure signal) detected by the discharge side pressure sensor 42.

[0131] The suction side pressure sensor 41, the intermediate chamber pressure sensor 55, and the discharge side pressure sensor 42 are arranged in this order in the flow direction of the liquid flowing through the suction pipe 10. Therefore, due to pressure loss occurring in the liquid, the pressure in the suction side region 56 (suction side pressure) is greater than the pressure in the intermediate chamber 46 (intermediate chamber side pressure) (suction side pressure > intermediate chamber side pressure), and the intermediate chamber side pressure is greater than the pressure in the discharge side region 57 (discharge side pressure) (intermediate chamber side pressure > discharge side pressure).

[0132] In this manner, a certain differential pressure relationship is established among the suction-side pressure, the intermediate chamber pressure, and the discharge-side pressure during operation of the pump device. Therefore, the control device 20 is configured to determine an abnormality in at least one of the suction-side pressure sensor 41, the intermediate chamber pressure sensor 55, and the discharge-side pressure sensor 42 based on such differential pressure relationships.

[0133] More specifically, the control device 20 determines an abnormality in at least one of the suction side pressure sensor 41, the intermediate chamber pressure sensor 55, and the discharge side pressure sensor 42 based on the comparison result between the suction side pressure signal and the intermediate chamber side pressure signal, and / or the comparison result between the discharge side pressure signal and the intermediate chamber side pressure signal.

[0134] Figure 19(a) is a table showing the sensor abnormality determination result determined based on the comparison result of the first differential pressure between the specified value and the comparison result of the second differential pressure between the specified value, and Figure 19(b) is a table showing the sensor abnormality determination result determined based on the pressure relationship between the suction side pressure, the intermediate chamber side pressure, and the discharge side pressure.

[0135] As shown in Fig. 19(a), the control device 20 may determine abnormalities in the suction side pressure sensor 41, the intermediate chamber pressure sensor 55, and the discharge side pressure sensor 42 based on the comparison result of the first differential pressure with a specified value and the comparison result of the second differential pressure with a specified value. As shown in Fig. 19(b), the control device 20 may determine abnormalities in the suction side pressure sensor 41, the intermediate chamber pressure sensor 55, and the discharge side pressure sensor 42 based on the pressure relationships among the suction side pressure, the intermediate chamber pressure, and the discharge side pressure.

[0136] 19(a), the control device 20 determines whether the differential pressure (first differential pressure) between the suction side pressure and the intermediate chamber side pressure is normal based on a predetermined specified value (e.g., 0.1 MPa). Similarly, the control device 20 determines whether the differential pressure (second differential pressure) between the intermediate chamber side pressure and the discharge side pressure is normal based on a predetermined specified value.

[0137] When both the first differential pressure and the second differential pressure are equal to or less than the specified value, the control device 20 determines that the suction side pressure sensor 41, the intermediate chamber pressure sensor 55, and the discharge side pressure sensor 42 are all normal.

[0138] When the first differential pressure is equal to or less than a specified value while the second differential pressure is higher than the specified value, the control device 20 determines that an abnormality has occurred in the discharge side pressure sensor 42. When the first differential pressure is higher than a specified value while the second differential pressure is equal to or less than a specified value, the control device 20 determines that an abnormality has occurred in the suction side pressure sensor 41. When both the first differential pressure and the second differential pressure are higher than the specified value, the control device 20 determines that an abnormality has occurred in both the suction side pressure sensor 41 and the discharge side pressure sensor 42.

[0139] As shown in Figure 19 (b), when the suction side pressure is greater than the intermediate chamber side pressure and the intermediate chamber side pressure is greater than the discharge side pressure, the control device 20 determines that the suction side pressure sensor 41, the intermediate chamber pressure sensor 55, and the discharge side pressure sensor 42 are all normal.

[0140] When the suction side pressure is greater than the intermediate chamber side pressure, while the discharge side pressure is greater than the intermediate chamber side pressure and the suction side pressure, the control device 20 determines that an abnormality has occurred in the discharge side pressure sensor 42. When the suction side pressure and the discharge side pressure are greater than the intermediate chamber side pressure, while the first differential pressure (i.e., the pressure difference between the suction side pressure and the intermediate chamber side pressure) is higher than a specified value, the control device 20 determines that an abnormality has occurred in the intermediate chamber pressure sensor 55.

[0141] When the suction side pressure and the discharge side pressure are greater than the intermediate chamber side pressure, while the first differential pressure is equal to or less than a specified value, the control device 20 determines that an abnormality has occurred in the discharge side pressure sensor 42. When the intermediate chamber side pressure is greater than the suction side pressure and the discharge side pressure, while the suction side pressure is less than the discharge side pressure, the control device 20 determines that an abnormality has occurred in the suction side pressure sensor 41.

[0142] When the intermediate chamber side pressure is greater than the suction side pressure but less than the discharge side pressure, and the second differential pressure (i.e., the pressure difference between the intermediate chamber side pressure and the discharge side pressure) is greater than a specified value, the control device 20 determines that there is an abnormality in the intermediate chamber pressure sensor 55. When the intermediate chamber side pressure is greater than the suction side pressure but less than the discharge side pressure, and the second differential pressure is equal to or less than a specified value, the control device 20 determines that there is an abnormality in the suction side pressure sensor 41.

[0143] If the water supply device 1 is equipped with both a suction pipe pressure sensor 101 and a suction side pressure sensor 41, the control device 20 may compare the pressure signal detected by the suction pipe pressure sensor 101 with the pressure signal detected by the suction side pressure sensor 41 to determine an abnormality in at least one of the suction side pressure sensor 41 and the suction pipe pressure sensor 101.

[0144] Since suction pipe pressure sensor 101 and suction side pressure sensor 41 are located close to each other, the pressure loss occurring in the liquid flowing through the flow path between suction pipe pressure sensor 101 and suction side pressure sensor 41 is small.

[0145] Therefore, the control device 20 measures the differential pressure between the pressure detected by the suction pipe pressure sensor 101 and the pressure detected by the suction side pressure sensor 41. The control device 20 then compares this differential pressure with a predetermined threshold value, and if the differential pressure is greater than the threshold value, determines that an abnormality has occurred in at least one of the suction side pressure sensor 41 and the suction pipe pressure sensor 101.

[0146] The configuration (method) for determining whether or not there is an abnormality in the check valve 90 (see FIG. 18) will be described below. As shown in FIG. 18, the operation inspection device 50 includes a check valve 90 arranged upstream of the on-off valve 53 in the flow direction of the liquid flowing through the connecting pipe 51.

[0147] The check valve 90 has the same structure as the check valve 90 in the embodiment described with reference to Fig. 15. If an abnormality occurs in the check function of the check valve 90 due to a foreign object being clogged in the check valve 90 or due to an abnormality in the spring of the check valve 90, the check valve 90 will not open properly and liquid will not flow downstream of the check valve 90.

[0148] The on-off valve 53 is a type of device (for example, a pilot-operated solenoid valve) that opens due to a pressure difference generated between the upstream and downstream sides of the on-off valve 53. When the on-off valve 53 is a pilot-operated solenoid valve, if an abnormality occurs in the check valve 90, no pressure difference is generated between the upstream and downstream sides of the on-off valve 53, and as a result, the on-off valve 53 does not operate properly.

[0149] Therefore, even if the control device 20 issues an "open" command to the on-off valve 53, liquid is not supplied to the backflow prevention device 15 through the connecting pipe 51, and the pressure signal detected by the intermediate chamber pressure sensor 55 does not change.

[0150] The intermediate chamber pressure sensor 55 is configured to detect a pressure signal as an index for determining whether or not there is an abnormality in the check valve 90 when the on-off valve 53 opens and closes with the connecting pipe 51 filled with liquid. The control device 20 is configured to determine whether or not there is an abnormality in the check valve 90 based on the pressure signal detected by the intermediate chamber pressure sensor 55.

[0151] When the control device 20 determines that an abnormality has occurred in the check valve 90, the control device 20 may execute a flushing operation to clean the check valve 90. By executing the flushing operation, liquid is forcefully supplied to the check valve 90, and foreign matter that has clogged the check valve 90 is removed.

[0152] The following describes a configuration (method) for determining whether or not there is an abnormality in the connecting pipe 51. When water is leaking from the connecting pipe 51, particularly when water is leaking from the connecting pipe 51 downstream of the on-off valve 53, the pressure signal detected by the intermediate chamber pressure sensor 55 decreases.

[0153] The intermediate chamber pressure sensor 55 is configured to detect a pressure signal as an index for determining whether or not water is leaking from the connecting pipe 51 when the on-off valve 53 is opening and closing with the connecting pipe 51 filled with liquid.

[0154] If water leakage occurs from the connecting pipe 51 downstream of the on-off valve 53, the pressure signal detected by the intermediate chamber pressure sensor 55 decreases even though the on-off valve 53 is in a closed state. Therefore, the control device 20 is configured to determine water leakage from the connecting pipe 51 based on the pressure signal detected by the intermediate chamber pressure sensor 55 during the opening and closing operation of the on-off valve 53 with the connecting pipe 51 filled with liquid.

[0155] More specifically, if water leakage occurs from the connecting pipe 51 downstream of the on-off valve 53, when the control device 20 issues a "close" command to the on-off valve 53, the pressure on the intermediate chamber side drops even though the connecting pipe 51 is closed. Therefore, when the control device 20 issues a "close" command to the on-off valve 53 while the pump device is stopped, if the pressure signal detected by the intermediate chamber pressure sensor 55 drops even though the control device 20 issues a "close" command to the on-off valve 53, it determines that water leakage from the connecting pipe 51 occurs.

[0156] When water leakage from the connecting pipe 51 occurs, the intermediate chamber pressure decreases while the suction side pressure and the discharge side pressure do not change. Therefore, the control device 20 may determine water leakage from the connecting pipe 51 based on the pressure signal detected by the intermediate chamber pressure sensor 55, the pressure signal detected by the suction side pressure sensor 41, and the pressure signal detected by the discharge side pressure sensor 42. With this configuration, the control device 20 can determine water leakage from the connecting pipe 51 with greater accuracy.

[0157] Although the pressure signal detected by the discharge pipe pressure sensor 102 decreases, the pressure signal detected by the intermediate chamber pressure sensor 55 may not change. In this case, the control device 20 may determine that water is leaking from the connecting pipe 51. For example, the control device 20 determines that water is leaking from the connecting pipe 51 upstream of the on-off valve 53.

[0158] More specifically, when the on-off valve 53 is opened and closed with the connecting pipe 51 filled with liquid, the control device 20 determines whether or not there is a leak in the connecting pipe 51 based on the pressure signal detected by the intermediate chamber pressure sensor 55 and the pressure signal detected by the discharge pipe pressure sensor 102.

[0159] In particular, when a large amount of liquid is leaking from the connecting pipe 51, liquid is also supplied from the pressure tank 28. In this case, the pressure signal detected by the discharge pipe pressure sensor 102 drops significantly. Therefore, the control device 20 may compare the pressure signal detected by the discharge pipe pressure sensor 102 with a predetermined set value, and determine that there is a leak from the connecting pipe 51 when the drop in the pressure signal detected by the discharge pipe pressure sensor 102 exceeds the predetermined set value.

[0160] 20(a) and 20(b) are diagrams showing an embodiment of an operation inspection device equipped with a strainer. In the embodiment shown in FIG. 20(a), the operation inspection device 50 is equipped with a strainer 100A arranged upstream of an on-off valve 53 (more specifically, a check valve 90). The strainer 100A is attached to a connecting pipe 51, and has a branch flow path that branches in a Y-shape from the flow path of the connecting pipe 51. One example of the strainer 100A is a Y-shaped strainer.

[0161] The operation inspection device 50 has a cross pipe section 110 arranged downstream of the on-off valve 53. The cross pipe section 110 is connected to the connecting pipe 51. The cross pipe section 110 is connected to the backflow prevention device 15, the intermediate chamber pressure sensor 55, and the air vent valve 52.

[0162] 20(b), the operation inspection device 50 includes a strainer 100B disposed on the flow path of the connecting pipe 51. In the embodiment shown in FIG. 20(b), the strainer 100B is also disposed upstream of the on-off valve 53 and attached to the connecting pipe 51.

[0163] 20(a) and 20(b), the connecting pipe 51 is connected to the discharge side of the pump 2, but the connecting pipe 51 does not necessarily have to be connected to the discharge side of the pump 2, and may be connected to a liquid supply source 120 (see FIGS. 17 and 18). Furthermore, the operation inspection device 50 does not necessarily have to include a check valve 90.

[0164] In the embodiments shown in Figures 20(a) and 20(b), since the strainers 100A and 100B both have similar functions, the inspection method of the operation inspection device 50 will be described below with reference to Figure 20(a).

[0165] The strainer 100A is configured to capture foreign matter and prevent the foreign matter from clogging the on-off valve 53 and the check valve 90. If foreign matter is captured in the strainer 100A and clogging occurs in the strainer 100A, the flow path of the connecting pipe 51 becomes narrow, and the flow of liquid is hindered.

[0166] In this case, when the operation inspection device 50 is inspecting the operation of the backflow prevention device 15, the amount of liquid supplied to the backflow prevention device 15 through the connecting pipe 51 decreases. As a result, the water leak detector 49 may not detect the water leak detection signal.

[0167] Therefore, the control device 20 is configured to determine whether the strainer 100A is clogged, based on a water leakage detection signal detected by the water leakage detector 49 during the opening and closing operation of the on-off valve 53 with the connecting pipe 51 filled with liquid. More specifically, the control device 20 determines whether the strainer 100A is clogged, if the water leakage detector 49 does not detect a water leakage detection signal even after the operation inspection device 50 starts inspecting the operation of the backflow prevention device 15.

[0168] After the control device 20 determines that the strainer 100A is clogged, the control device 20 may execute a flushing operation to clean the strainer 100A. By executing the flushing operation, liquid is forcefully supplied to the strainer 100A, and as a result, foreign matter clogged in the strainer 100A is removed.

[0169] 21(a) and 21(b) are diagrams showing another embodiment of the operation inspection device equipped with a strainer. In the embodiment shown in FIG. 21(a) and FIG. 21(b), the check valve 90 is disposed downstream of the on-off valve 53. In such an embodiment, the strainer 100A (and the strainer 100B) are disposed upstream of the on-off valve 53. The control device 20 is configured to determine the presence or absence of clogging of the strainer 100A (and the strainer 100B) by a method similar to that of the embodiment shown in FIG. 20(a) and FIG. 20(b).

[0170] In the above-described embodiment, the storage device 62 stores a program including instructions for executing the inspection method of the operation inspection device 50 and a program including instructions for executing a flushing operation. The processing device 65 executes the inspection operation program of the operation inspection device 50 and the flushing operation program in accordance with the programs stored in the storage device 62.

[0171] In the above-described embodiment, an embodiment has been described in which the control device 20 executes an inspection method for the operation inspection device 50 and a maintenance method for the operation inspection device 50. However, the inspection method and / or maintenance method for the operation inspection device 50 do not necessarily have to be executed by the control device 20, and an operator (human) may access the water supply device 1 and directly execute the inspection method and / or maintenance method for the operation inspection device 50.

[0172] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and it is needless to say that the present invention may be embodied in various different forms within the scope of the technical concept thereof. [Explanation of symbols]

[0173] 1 Water supply device 2. Pump 3 Motor 5 Introductory tube 7 Water pipe 8 Discharge pipe 9 Suction connection pipe 10 Suction pipe 13 Pipe silencer 15 Backflow prevention device 18 Suction header pipe 20 Control device 21 Inverter 27 Discharge connection pipe 28 Pressure Tank 30 Cabinet 40 Leakage catcher 41 Suction side pressure sensor 42 Discharge side pressure sensor 43 First check valve 44 Second check valve 45 Relief valve 46 Intermediate Room 47 Outlet 48 Valve box 49 Water Leak Detector 50 Operational inspection device 51 Connecting pipe 52 Air vent valve 53 On-off valve 54 Flow rate adjustment device 55 Intermediate chamber pressure sensor 56 Suction side area 57 Discharge side area 60 Substrates 61 Option board 63 Upper device 64 External display controller 65 Processing Equipment 67,68 Flow rate adjustment device 70A,70B Flexible piping 75 On-off valve 80 Suction side differential pressure sensor 81 Discharge side differential pressure sensor 90 Check valve 91 Pressure Pump 92 On-off valve 100A, 100B Strainer 101 Suction pipe pressure sensor 102 Discharge pipe pressure sensor 110 Cross pipe section 120 Liquid Source

Claims

1. A connecting pipe connected to the backflow prevention device; an on-off valve for opening and closing the connecting pipe; an intermediate chamber pressure sensor for detecting a pressure in an intermediate chamber of the backflow prevention device; The intermediate chamber pressure sensor is configured to detect a pressure signal as an indicator for determining an abnormality in the on-off valve when the on-off valve is opened or closed with the connecting pipe filled with liquid.

2. The operation inspection device of claim 1, wherein the intermediate chamber pressure sensor is configured to detect a pressure signal as an indicator for determining an abnormality in the intermediate chamber pressure sensor based on a comparison result with a suction side pressure signal detected by a suction side pressure sensor arranged on the suction side of the backflow prevention device, and / or a comparison result with a discharge side pressure signal detected by a discharge side pressure sensor arranged on the discharge side of the backflow prevention device.

3. The operation inspection device includes a check valve arranged upstream of the on-off valve in a flow direction of liquid flowing through the connecting pipe, 2. The operation inspection device according to claim 1, wherein the intermediate chamber pressure sensor is configured to detect a pressure signal as an indicator for determining an abnormality in the check valve when the on-off valve is opened or closed with the connecting pipe filled with liquid.

4. 2. The operation inspection device according to claim 1, wherein the intermediate chamber pressure sensor is configured to detect a pressure signal as an indicator for determining whether water is leaking from the connecting pipe when the opening / closing valve is opening and closing with the connecting pipe filled with liquid.

5. A pump device; An operation inspection device for inspecting the operation of a backflow prevention device disposed on the suction side of the pump device; A control device for determining an abnormality in the operation inspection device, The operation inspection device includes: a connecting pipe connected to the backflow prevention device; an on-off valve for opening and closing the connecting pipe, The control device of the water supply device is configured to determine an abnormality in the on-off valve based on a pressure signal detected by a discharge pipe pressure sensor connected to a discharge pipe arranged on the discharge side of the pump device and a water leakage detection signal detected by a water leakage detector of the backflow prevention device when the on-off valve is opened and closed when the connecting pipe is filled with liquid.

6. The water supply device of claim 5, wherein the control device is configured to determine water leakage from the connecting pipe based on a pressure signal detected by the discharge pipe pressure sensor when the opening and closing operation of the on-off valve is performed when the connecting pipe is filled with liquid.

7. The operation inspection device includes a strainer attached to the connecting pipe, The water supply device of claim 5, wherein the control device is configured to determine whether the strainer is clogged based on a leak detection signal detected by the water leak detector when the opening and closing operation of the on-off valve is performed when the connecting pipe is filled with liquid.

8. A pump device; An operation inspection device for inspecting the operation of a backflow prevention device disposed on the suction side of the pump device; A control device for determining an abnormality in the operation inspection device, The operation inspection device includes: a connecting pipe connected to the backflow prevention device; an on-off valve for opening and closing the connecting pipe, The control device, while the pump device is not operating, periodically repeats the opening and closing operation of the on-off valve to supply liquid to the connecting pipe and perform a flushing operation to clean the operation inspection device.

9. The operation inspection device includes a strainer attached to the connecting pipe, The water supply apparatus according to claim 8 , wherein the control device executes the flushing operation to clean the strainer.

10. 1. A method for inspecting an operation inspection device including a connecting pipe connected to a backflow prevention device, an on-off valve for opening and closing the connecting pipe, and an intermediate chamber pressure sensor for detecting a pressure in an intermediate chamber of the backflow prevention device, comprising: An inspection method for an operation inspection device, comprising determining an abnormality in the on-off valve based on a pressure signal detected by the intermediate chamber pressure sensor during opening and closing operations of the on-off valve with the connecting pipe filled with liquid.

11. 11. The inspection method for an operation inspection device as described in claim 10, wherein, during the opening and closing operation of the on-off valve with the connecting pipe filled with liquid, an abnormality in the on-off valve is determined based on a pressure signal detected by a discharge pipe pressure sensor connected to a discharge pipe arranged on the discharge side of the pump device and a water leakage detection signal detected by a water leakage detector of the backflow prevention device.

12. 11. The inspection method for an operation inspection device as described in claim 10, further comprising determining an abnormality in at least one of the suction side pressure sensor, the intermediate chamber pressure sensor, and the discharge side pressure sensor based on a comparison result between a suction side detection signal detected by a suction side pressure sensor arranged on the suction side of the backflow prevention device and an intermediate chamber side pressure signal detected by the intermediate chamber pressure sensor, and / or a comparison result between a discharge side detection signal detected by a discharge side pressure sensor arranged on the discharge side of the backflow prevention device and the intermediate chamber side pressure signal.

13. The operation inspection device includes a check valve arranged upstream of the on-off valve in a flow direction of liquid flowing through the connecting pipe, 11. The method for inspecting an operation inspection device according to claim 10, further comprising determining an abnormality in the check valve based on a pressure signal detected by the intermediate chamber pressure sensor during opening and closing operations of the on-off valve with the connecting pipe filled with liquid.

14. 11. The method for inspecting an operation inspection device according to claim 10, further comprising determining whether or not there is a leak in the connecting pipe based on a pressure signal detected by the intermediate chamber pressure sensor and a pressure signal detected by the discharge pipe pressure sensor during opening and closing operations of the on-off valve with the connecting pipe filled with liquid.

15. A maintenance method for an operation inspection device including a connecting pipe connected to a backflow prevention device and an on-off valve for opening and closing the connecting pipe, comprising: A maintenance method for an operation inspection device, comprising periodically repeating the opening and closing operation of the on-off valve while the pump device is not operating, supplying liquid to the connecting pipe, and performing a flushing operation to clean the operation inspection device.

16. The operation inspection device includes a strainer attached to the connecting pipe, The maintenance method for an operation and inspection device according to claim 15, further comprising the step of: performing the flushing operation to clean the strainer.

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