JP7686528B2 - fluid circulation device - Google Patents

Description

The present invention relates to a fluid circulation device.

Patent Document 1 discloses a storage type water heater, which is an example of a conventional fluid circulation device. This storage type water heater is a stationary type, and includes a circulation circuit, which is an example of a flow path, a heat source pump, a flow sensor, which is an example of a flow rate measurement unit, a control unit, which is an example of a memory unit and a state determination unit, and an alarm unit.

The circulation circuit circulates hot water, which is an example of a fluid. The heat source pump is provided in the circulation circuit and pumps the hot water. The flow sensor measures the flow rate of the hot water circulating through the circulation circuit.

The control unit has a memory circuit and determines whether the flow sensor is malfunctioning or not based on the normal range of the flow sensor and the measurement results of the flow sensor that are pre-stored in the memory circuit, and causes the notification unit to notify the user of the malfunction or not.

JP 2016-217551 A

In conventional fluid circulation devices such as the above-mentioned storage-type hot water heater, the flow rate measuring unit outputs a signal corresponding to the flow rate of the fluid flowing through the flow path, and any one of a number of flow rate measuring units, each with different measurement specifications, which are the correlation between flow rate and signal, can be selected and attached to the flow path.

A specific example of a configuration with different measurement specifications is an impeller-type flow measurement unit in which the shape of the mounting part of the housing and the inner diameter of the internal flow passage are the same, but the impeller rotation speed differs when the flow rate is the same due to differences in the blade shape of the impeller placed in the internal flow passage, resulting in a different number of signal pulses.

Another specific example is an impeller-type flow rate measurement unit in which the shape of the mounting part of the housing is the same, but the inner diameter of the internal flow path and the size of the impeller are different, resulting in different impeller rotation speeds when the flow rate is the same, resulting in different numbers of signal pulses.

If the configuration allows any one of a number of flow rate measuring units, each with different measurement specifications, to be selected and attached to the flow path, there is a possibility that, during replacement of the flow rate measuring unit, a flow rate measuring unit with measurement specifications different from the installed flow rate measuring unit will be mistakenly attached.

In this case, even if the state determination unit performs a determination similar to that of a flow sensor failure in the storage type water heater described above, it will only determine that the flow measurement unit has failed, and will not be able to determine whether the measurement specifications of the flow measurement unit are different before and after the replacement work.

In addition, in a stationary fluid circulation device, the length of the flow path varies greatly depending on the various installation locations. For example, if the fluid circulation device is a water heater, the length of the flow path connecting the water heater, which is mainly installed outdoors in a house or facility, to the faucets and other fittings installed in the kitchen, bathroom, etc., varies greatly depending on the size of the house, etc.

For this reason, the measurement specifications after installation for each flow measurement unit tend to vary greatly from the measurement specifications at the time of design. As a result, with this fluid circulation device, even if the measurement specifications at the time of design for each flow measurement unit are stored in advance in the memory unit and used to judge the flow measurement units, it is difficult to make accurate judgments.

The present invention was made in consideration of the above-mentioned conventional situation, and aims to provide a fluid circulation device that can accurately determine whether the measurement specifications of the flow measurement unit are different before and after replacement work.

The fluid circulating device of the present invention includes a flow path for circulating a fluid,
a pump provided in the flow path for pumping the fluid;
a flow rate measuring unit that outputs a signal corresponding to a flow rate of the fluid flowing through the flow path, the flow rate measuring unit being attached to the flow path by selecting any one of a plurality of flow rate measuring units each having a different measurement specification, which is a correlation between the flow rate and the signal;
A storage unit that stores at least the signal;
A state determination unit that determines a state of the flow rate measurement unit;
A notification unit that issues a notification;
A stationary fluid circulation device comprising:
The state determination unit is
a post-installation check process in which, when the installation work of the fluid circulation device is completed, the pump is operated under a predetermined test operation condition, and the signal output by the flow rate measurement unit is stored in the memory unit as a post-installation signal;
a reference range setting process for setting an upper limit value and a lower limit value by taking into account a predetermined allowable error in the post-installation signal stored in the storage unit;
a post-replacement check process in which, when the replacement work of the flow rate measuring unit is completed, the pump is operated under the test operation conditions and the signal output by the flow rate measuring unit is stored in the memory unit as a post-replacement signal;
a determination process for determining that a first error has occurred in which the measurement specifications of the flow rate measurement unit are different before and after the replacement work when the post-replacement signal is greater than the upper limit value or less than the lower limit value, and forcing the notification unit to issue a first notification corresponding to the first error;
The present invention is characterized in that the present invention is configured to execute the following:

In the fluid circulation device of the present invention, the state determination unit stores a post-installation signal in the memory unit when the installation work is completed during the post-installation check process. The post-installation signal corresponds to the length of the flow path according to the installation location of the fluid circulation device, and accurately reflects the measurement specifications after the flow rate measurement unit is installed, i.e., before replacement.

Next, in the reference range setting process, the state determination unit sets the upper and lower limit values by taking into account a predetermined allowable error in the post-installation signal.

Next, in the post-replacement check process, the status determination unit stores the post-replacement signal in the memory unit when the replacement work of the flow measurement unit is completed.

Next, in the determination process, the state determination unit uses the upper and lower limit values based on the post-installation signal to compare with the post-replacement signal to determine whether the measurement specifications of the flow measurement unit are different before and after the replacement work.

In other words, the state determination unit uses a post-installation signal that corresponds to the length of the flow path according to the installation location of the fluid circulation device and accurately reflects the measurement specifications after the flow measurement unit is installed, i.e., before replacement, to determine the flow measurement unit, thereby improving the accuracy of determination compared to a case in which the measurement specifications at the time of design of each flow measurement unit are pre-stored in the memory unit and used to determine the flow measurement unit.

The fluid circulation device of the present invention can therefore accurately determine whether the measurement specifications of the flow measurement unit are different before and after replacement work. As a result, if it is determined that the measurement specifications of the flow measurement unit in this fluid circulation device are different before and after replacement work, the replacement worker can quickly replace the incorrect flow measurement unit with the correct flow measurement unit.

It is preferable that the storage unit prestores a threshold value that is lower than the respective lower limit values of the flow rate measuring units and greater than zero. Then, in the determination process, if the post-replacement signal is smaller than the threshold value, the state determination unit determines that a second error has occurred, in which the post-replacement flow rate measuring unit has failed, and causes the notification unit to issue a second notification corresponding to the second error, rather than the first notification.

In this case, the state determination unit can distinguish between the occurrence of a first error and the occurrence of a second error in the determination process, and can cause the notification unit to issue a first notification if it determines that a first error has occurred, and can cause the notification unit to issue a second notification if it determines that a second error has occurred. This allows the fluid circulation device to more accurately determine whether the measurement specifications of the flow measurement unit are different before and after the replacement work and notify the replacement worker, as well as distinguish between a state in which the flow measurement unit has failed after replacement and notify the replacement worker. As a result, it is possible to improve convenience for the replacement worker.

The fluid circulation device of the present invention can accurately determine whether the measurement specifications of the flow rate measuring unit are different before and after replacement work.

FIG. 1 is a schematic diagram of a water heater according to an embodiment of the present invention. FIG. 2 is a graph illustrating a post-installation signal, an upper limit value, a lower limit value, and a threshold value for a plurality of flow rate measuring units each having different measurement specifications. FIG. 3 is a flowchart of a first program relating to the post-installation check process and the reference range setting process. FIG. 4 is a flowchart of a second program relating to the post-replacement check process and the determination process.

The following describes an embodiment of the present invention with reference to the drawings.

(Example)
As shown in Fig. 1, a water heater 1 of the embodiment is an example of a specific aspect of the fluid circulating device of the present invention. The water heater 1 is a free-standing type that is mainly installed outdoors in a house or the like, and is a device that supplies high-temperature hot water to a mixer faucet 8 installed in a kitchen, a bathroom, or the like.

The water heater 1 includes a control unit C1, a gas burner 7, a fuel gas pipe 71, a main valve 72, and a flow rate control valve 73 in a housing 1B that is substantially box-shaped.

The control unit C1 is an electronic circuit unit that includes a CPU (not shown), a memory unit C1M composed of memory elements such as ROM and RAM, an interface circuit that transmits and receives signals to and from the controlled object, and a power supply circuit that controls the power supply to the controlled object.

The memory unit C1M stores various programs and setting information for operating the water heater 1. The memory unit C1M also appropriately stores various information acquired by the control unit C1 during operation of the water heater 1.

The programs stored in the memory unit C1M include a "first program for post-installation check processing and reference range setting processing" shown in FIG. 3 and a "second program for post-replacement check processing and determination processing" shown in FIG. 4. When the control unit C1 executes the first program and the second program, a part of the control unit C1 functions as a state determination unit C1J and a notification unit C1N, which will be described later.

The fuel gas pipe 71 is connected to a fuel gas supply source (not shown), such as a city gas supply pipe, and supplies fuel gas to the gas burner 7. The main valve 72 is an electromagnetic valve that switches the fuel gas pipe 71 on and off. The flow rate adjustment valve 73 is an electromagnetic valve that adjusts the flow rate of the fuel gas supplied to the gas burner 7 via the fuel gas pipe 71.

The gas burner 7 starts burning when the main valve 72 is opened under the control of the control unit C1 and ignited by an ignition device (not shown). The gas burner 7 then burns with a firepower according to the hot water supply load by adjusting the opening of the flow rate control valve 73 and the rotation speed of the blower fan (not shown) under the control of the control unit C1, and generates combustion exhaust gas.

The water heater 1 also includes a heat exchanger 3, a first internal pipe 31, a second internal pipe 32, a first temperature sensor 31T, a flow rate measuring unit 10, a second temperature sensor 32T, and a pump 5 within the housing 1B.

The heat exchanger 3 is located above the gas burner 7. The lower end of the first internal pipe 31 is connected to a pipe joint 91 arranged on the bottom wall of the housing 1B. The upper end of the first internal pipe 31 is connected to the water inlet side of the heat exchanger 3. The upper end of the second internal pipe 32 is connected to the water outlet side of the heat exchanger 3. The lower end of the second internal pipe 32 is connected to a pipe joint 92 arranged on the bottom wall of the housing 1B.

The first temperature sensor 31T is disposed midway through the first internal pipe 31, close to the lower end of the first internal pipe 31. The first temperature sensor 31T measures the temperature of the hot water flowing through the first internal pipe 31, i.e., the hot water before it is heated by the heat exchanger 3, and transmits the measurement result to the control unit C1.

The flow rate measuring unit 10 is disposed midway through the first internal pipe 31. The flow rate measuring unit 10 measures the flow rate of hot and cold water flowing through the first internal pipe 31 and transmits the measurement result to the control unit C1. The details of the flow rate measuring unit 10 will be described in detail later.

The second temperature sensor 32T is disposed midway through the second internal pipe 32. The second temperature sensor 32T measures the temperature of the hot water flowing through the second internal pipe 32, i.e., the hot water after being heated by the heat exchanger 3, and transmits the measurement result to the control unit C1.

The pump 5 is disposed midway through the second internal pipe 32, close to the lower end of the second internal pipe 32. The pump 5 is operated under the control of the control unit C1, and pumps hot water toward the lower end of the second internal pipe 32.

Furthermore, the water heater 1 has a first external pipe 41, a second external pipe 42, and a third external pipe 43 outside the housing 1B.

One end of the first external pipe 41 is connected to the lower end of the first internal pipe 31 via a pipe joint 91. The other end of the first external pipe 41 is connected to a T-type pipe joint 93.

One end of the second external pipe 42 is connected to the lower end of the second internal pipe 32 via a pipe joint 92. The other end of the second external pipe 42 is connected to one end of the third external pipe 43 and to the high-temperature water inlet pipe 8H of the mixer tap 8 via a T-shaped pipe joint 94.

The other end of the third external pipe 43 is connected to the other end of the first external pipe 41 via a T-type pipe joint 93.

A check valve 43V is disposed in the third external pipe 43 near the T-shaped pipe joint 93. The check valve 43V allows hot and cold water in the third external pipe 43 to flow toward the first external pipe 41, but prevents it from flowing in the opposite direction.

The other end of the first external pipe 41 and the other end of the third external pipe 43 are connected to one end of the first water supply branch pipe 51 via a T-shaped pipe joint 93.

The other end of the first water supply branch pipe 51 is connected to one end of the main water supply pipe 50 and one end of the second water supply branch pipe 52 via a T-shaped pipe joint 95.

The other end of the main water supply pipe 50 is connected to a water supply source (not shown), such as a water supply system. The other end of the second water supply branch pipe 52 is connected to the low-temperature water inlet pipe 8L of the mixer tap 8.

A check valve 50V is disposed in the middle of the main water supply pipe 50. The check valve 50V allows hot and cold water in the main water supply pipe 50 to flow toward the first water supply branch pipe 51 and the second water supply branch pipe 52, but prevents it from flowing in the opposite direction.

An expansion valve 50W is disposed in the main water supply pipe 50 near the T-type pipe joint 95. The expansion valve 50W absorbs the increase in pressure in the main water supply pipe 50, the first branch water supply pipe 51, and the second branch water supply pipe 52.

The main water supply pipe 50 and the first water supply branch pipe 51 supply unheated water to the first internal pipe 31 of the water heater 1 via the first external pipe 41.

The water heater 1 is equipped with a water supply flow rate measuring unit 15 arranged in the middle of the first water supply branch pipe 51. The water supply flow rate measuring unit 15 measures the flow rate of water circulating in the first water supply branch pipe 51 and transmits the measurement result to the control unit C1.

The main water supply pipe 50 and the second water supply branch pipe 52 supply unheated water to the low-temperature water inlet pipe 8L of the mixer tap 8 when the low-temperature water discharge side of the mixer tap 8 is opened.

The water heater 1 is equipped with a remote control 80 that is installed near the mixer tap 8 in the kitchen, bathroom, etc. The remote control 80 has an operation unit 81 and a display unit 82.

The operation unit 81 has multiple buttons and accepts operation inputs such as starting and stopping the water heater 1, executing instant hot water operation, and inputting various setting information such as the target hot water temperature. The operation inputs received by the operation unit 81 are transmitted to the control unit C1.

The display unit 82 is a liquid crystal display or the like. The display unit 82 is controlled by the control unit C1 to appropriately display the operating status of the water heater 1, various setting information, error messages, etc.

<Hot water supply operation>
When a user operates the remote control 80 to start up the water heater 1, the control unit C1 goes into a standby state for hot water supply operation.

During hot water supply operation, the control unit C1 sets the gas burner 7 in a standby state in which it can be ignited immediately. During hot water supply operation, the pump 5 remains stopped and does not interfere with the flow of hot water and water in the second internal piping 32.

When the high-temperature water discharge side of the mixing faucet 8 is opened, water supplied from the water supply source flows through the main water supply pipe 50, the first water supply branch pipe 51, the first external pipe 41, the first internal pipe 31, the heat exchanger 3, the second internal pipe 32, the second external pipe 42 and the high-temperature water inlet pipe 8H, and is discharged from the mixing faucet 8.

At this time, the control unit C1 determines that the high-temperature water discharge side of the mixing valve 8 has been opened based on the fact that the measured flow rates of the feedwater flow rate measurement unit 15 and the flow rate measurement unit 10 are greater than zero, and immediately ignites the gas burner 7. The heat exchanger 3 heats the water flowing inside with the combustion exhaust gas generated by the gas burner 7.

Then, based on the measurement results of the first temperature sensor 31T and the second temperature sensor 32T, the control unit C1 adjusts the heat of the gas burner 7 so that the temperature of the hot water dispensed from the water heater 1 becomes the target hot water supply temperature. As a result, high-temperature water is discharged from the mixing tap 8. If the low-temperature water discharge side of the mixing tap 8 is also open, the mixing tap 8 mixes the high-temperature water with low-temperature water and discharges it.

When the hot water discharge side of the mixer tap 8 is closed or when the user operates the remote control 80 to stop the water heater 1, the control unit C1 turns off the gas burner 7 and ends the hot water supply operation.

<Instant hot water operation>
When a user operates the remote control 80 to start the water heater 1 and selects the instant hot water operation, the control unit C1 starts the instant hot water operation.

In the instant hot water operation, the control unit C1 activates the pump 5 and ignites the gas burner 7. Then, the first external pipe 41, the first internal pipe 31, the heat exchanger 3, the second internal pipe 32, the second external pipe 42, and the third external pipe 43 circulate the hot water pressurized by the pump 5. The heat exchanger 3 heats the water flowing inside with the combustion exhaust gas generated by the gas burner 7.

The circulation flow path 2 is composed of the first external pipe 41, the first internal pipe 31, the heat exchanger 3, the second internal pipe 32, the second external pipe 42, and the third external pipe 43. The circulation flow path 2 is an example of a "flow path" in the present invention. Hot water is an example of a "fluid" in the present invention.

Based on the fact that the measured flow rate of the water supply flow rate measuring unit 15 is zero, the control unit C1 determines that the hot water discharge side of the mixer tap 8 is closed, and determines that the measured flow rate of the flow rate measuring unit 10 is the flow rate of hot water circulating through the circulation flow path 2.

Based on the measurement results of the first temperature sensor 31T and the second temperature sensor 32T, the control unit C1 adjusts the heat of the gas burner 7 or burns the gas burner 7 intermittently so that the temperature of the hot water circulating through the circulation flow path 2 becomes the target hot water temperature.

When the hot water discharge side of the mixer tap 8 is opened, a portion of the hot water circulating through the circulation flow path 2 flows from the other end of the first external pipe 41 into the hot water inlet pipe 8H of the mixer tap 8. As a result, hot water is immediately discharged from the mixer tap 8. When the cold water discharge side of the mixer tap 8 is also opened, the mixer tap 8 mixes the hot water with cold water and discharges it.

At this time, the main water supply pipe 50 and the first water supply branch pipe 51 replenish water to the circulation flow path 2 according to the amount of water flowing out from the circulation flow path 2 to the high-temperature water inlet pipe 8H. Based on the fact that the measured flow rate of the water supply flow rate measuring unit 15 is greater than zero, the control unit C1 determines that the high-temperature water discharge side of the mixing faucet 8 has been opened, and determines that water has been replenished to the circulation flow path 2 and the temperature of the hot water has dropped.

Then, the control unit C1 adjusts the heat of the gas burner 7 based on the measurement results of the first temperature sensor 31T and the second temperature sensor 32T so that the temperature of the hot water circulating through the circulation flow path 2 becomes the target hot water supply temperature.

When the user operates the remote control 80 to stop the water heater 1, the control unit C1 turns off the gas burner 7 and stops the pump 5, terminating the instant hot water operation.

<Flow rate measurement section details>
Although the illustration is simplified, the flow measuring unit 10 has a housing having an attachment portion for attachment to the middle of the first internal pipe 31, an internal flow path formed in the housing, and an impeller arranged in the internal flow path.

The impeller can rotate around a rotation axis parallel to the direction in which the internal flow path extends, and has blades that extend in a spiral shape around the rotation axis. The number of rotations per unit time (seconds) of the impeller increases in proportion to the flow rate of hot and cold water flowing through the first internal piping 31.

The flow rate measuring unit 10 also has a magnet attached to the outer periphery of the impeller and a magnet sensor attached to a location close to the inner wall surface of the internal flow path in the housing. The internal contacts of the magnet sensor are disconnected while the magnet is separated during one rotation of the impeller, and switch to a connected state only when the magnet is closest to the magnet, transmitting a single pulse signal.

As a result, the signal (number of pulses/second) emitted by the flow rate measuring unit 10 increases in proportion to the flow rate of hot and cold water flowing through the first internal pipe 31.

The flow rate of hot and cold water flowing through the first internal pipe 31 increases in proportion to the number of revolutions per unit time (second) of the pump 5. In other words, the signal (number of pulses/second) emitted by the flow rate measuring unit 10 increases in proportion to the number of revolutions per unit time (second) of the pump 5.

The correlation between the flow rate of hot and cold water flowing through the first internal pipe 31 (the number of rotations of the pump 5 per unit time (second)) and the signal of the flow rate measuring unit 10 (number of pulses/second) is set as the measurement specification of the flow rate measuring unit 10.

The flow rate measuring unit 10 is selected from two flow rate measuring units 10 with different measurement specifications, namely, the first flow rate measuring unit 10A and the second flow rate measuring unit 10B, and is attached to the first internal pipe 31.

The first flow rate measuring unit 10A and the second flow rate measuring unit 10B have the same shape of the mounting part of the housing and the same inner diameter of the internal flow path, but due to differences in the shape of the impeller blades placed in the internal flow path, the impeller rotation speed differs when the flow rate is the same, and as a result, the number of signal pulses differs.

More specifically, an example of the measurement specifications of the first flow rate measuring unit 10A after the hot water heater 1 is installed is shown by the solid line L1 in FIG. 2. Also, an example of the measurement specifications of the second flow rate measuring unit 10B after the hot water heater 1 is installed is shown by the two-dot chain line L2 in FIG. 2.

Compared to the first flow measurement unit 10A, the second flow measurement unit 10B is a low flow rate operation type in which the impeller starts to rotate at low flow rates. Also, compared to the first flow measurement unit 10A, the second flow measurement unit 10B has a higher impeller rotation speed at the same flow rate and a higher number of pulses per second in the signal.

The second flow rate measuring unit 10B is used to configure the water heater 1 so that it can respond accurately to the detailed operation of the mixer tap 8 and supply hot water.

The selection of the first flow rate measuring unit 10A or the second flow rate measuring unit 10B is performed when the water heater 1 is manufactured, and the control unit C1 is also set to determine the flow rate of hot and cold water flowing through the first internal piping 31 according to the measurement specifications of the selected first flow rate measuring unit 10A or second flow rate measuring unit 10B.

The homes in which the water heater 1 is installed vary in size and the arrangement of multiple rooms. For this reason, the length of the circulation path 2 of the water heater 1 varies depending on the home in which the water heater 1 is installed, so the measurement specifications of the first flow rate measuring unit 10A after the water heater 1 is installed may deviate from the solid line L1, and the measurement specifications of the second flow rate measuring unit 10B after the water heater 1 is installed may deviate from the two-dot chain line L2.

<First and second programs for determining whether the measurement specifications of the flow rate measuring unit are different before and after replacement work>
When the water heater 1 is installed in a house and used for a long period of time, the flow rate measuring unit 10 may be replaced with a new one for maintenance or repair. In this case, during the replacement of the flow rate measuring unit 10, a malfunction may occur in which the second flow rate measuring unit 10B having different measurement specifications from the first flow rate measuring unit 10A after installation is mistakenly attached to the first internal piping 31, or the first flow rate measuring unit 10A having different measurement specifications from the second flow rate measuring unit 10B after installation is mistakenly attached to the first internal piping 31.

In order to notify the replacement operator of such a malfunction when it occurs, the control unit C1 executes the "first program for post-installation check processing and reference range setting processing" shown in FIG. 3 and the "second program for post-replacement check processing and judgment processing" shown in FIG. 4.

After the installation of the water heater 1 is completed, when the installer operates the remote control 80 to turn on the power to the water heater 1 and perform a trial run, the control unit C1 executes the first program shown in FIG. 3 as one of multiple function confirmation tests.

Steps S101 and S102 shown in FIG. 3 are an example of the "post-installation check process" of the present invention. Step S111 shown in FIG. 3 is an example of the "reference range setting process" of the present invention.

First, in step S101, the state determination unit C1J, which is part of the control unit C1, operates the pump 5 under predetermined test operation conditions. The hot and cold water in the circulation flow path 2 is pumped by the pump 5 and circulated.

The specified test operation conditions are that the circulation flow path 2, the main water supply pipe 50, the first branch water supply pipe 51, the second branch water supply pipe 52, the high-temperature water inlet pipe 8H, and the low-temperature water inlet pipe 8L are filled with water, the mixing valve 8 is closed, and the pump 5 is rotated at the rotation speed R1 shown in Figure 2.

The rotation speed R1 is set to a rotation speed at which the impellers of the first flow measurement unit 10A and the second flow measurement unit 10B rotate stably at high speed.

When the pump 5 operates at the rotation speed R1, if there is an initial defect, the intrusion of a foreign object, or an installation defect in the first flow measurement unit 10A or the second flow measurement unit 10B, the rotation speed of the impeller will be significantly lower than in a normal state, and the number of pulses per second in the signal will be significantly lower. For this reason, the memory unit C1M pre-stores the threshold value G2 shown in FIG. 2.

During the development of the water heater 1, the first flow measuring unit 10A and the second flow measuring unit 10B were subjected to test operations for initial defects, intrusion of foreign matter, installation defects, etc., and the threshold value G2 was set to a value greater than the result of measuring the number of pulses per second in the signal when the pump 5 operates at the rotation speed R1. Furthermore, the threshold value G2 was set sufficiently low with respect to the measurement specifications at the time of designing the first flow measuring unit 10A and the measurement specifications at the time of designing the second flow measuring unit 10B, taking into account variations in the installation location.

The threshold value G2 thus set is lower than the lower limit values G1L (G1LA, G1LB) of the first flow measurement unit 10A and the second flow measurement unit 10B, which will be described later, and is greater than zero.

Next, the state determination unit C1J proceeds to step S102 shown in FIG. 3, and stores the signal output by the flow measurement unit 10 in the memory unit C1M as a post-installation signal SG1.

As shown in FIG. 2, if the flow measurement unit 10 after installation is the first flow measurement unit 10A, the state determination unit C1J stores the signal SG1A output by the first flow measurement unit 10A in the memory unit C1M as the post-installation signal SG1.

On the other hand, if the flow measurement unit 10 after installation is the second flow measurement unit 10B, the state determination unit C1J stores the signal SG1B output by the second flow measurement unit 10B in the memory unit C1M as the post-installation signal SG1.

Then, the state determination unit C1J proceeds to step S105 shown in FIG. 3, and determines whether the post-installation signal SG1 (SG1A or SG1B) is smaller than the threshold value G2. If the answer is "Yes" in step S105, the state determination unit C1J proceeds to step S106. On the other hand, if the answer is "No" in step S105, the state determination unit C1J proceeds to step S111.

When the process moves from step S105 to step S106, the state determination unit C1J determines that the flow measurement unit 10 after installation is in a faulty state.

Then, the state determination unit C1J proceeds to step S107 and causes the notification unit C1N, which is part of the control unit C1, to issue a notification to notify the user of a malfunction of the flow measurement unit 10 after installation. The notification unit C1N controls the display unit 82 of the remote control 80 to display an error message to notify the user of a malfunction of the flow measurement unit 10.

Then, the status determination unit C1J ends the first program. The installer who sees the error message can quickly replace the faulty flow measurement unit 10 with a normal flow measurement unit 10.

When the process moves from step S105 to step S111, the state determination unit C1J sets the upper limit value G1H (G1HA or G1HB) and the lower limit value G1L (G1LA or G1LB) by adding a predetermined allowable error T1 to the post-installation signal SG1 (SG1A or SG1B) stored in the memory unit C1M, as shown in FIG. 2. After that, the state determination unit C1J ends the first program.

Here, when taking into account the predetermined allowable error T1 to the post-installation signal SG1, addition, subtraction, multiplication, division, etc. will be used. As an example, the case where the allowable error T1 is a percentage will be shown below.
Upper limit value G1H=post-installation signal SG1×(1+predetermined allowable error T1(%)/100)
Lower limit G1L=Post-installation signal SG1×(1−Predetermined allowable error T1(%)/100)

When the water heater 1 is installed in a house and used for a long period of time, the flow rate measuring unit 10 is replaced, and the replacement is completed, the replacement worker operates the remote control 80 to turn on the water heater 1 and perform a trial run. The control unit C1 then executes the second program shown in FIG. 4 as one of multiple function confirmation tests.

Steps S121 and S122 shown in FIG. 4 are an example of the "post-replacement check process" of the present invention. Steps S131 to S138 shown in FIG. 4 are an example of the "determination process" of the present invention.

First, in step S121, the state determination unit C1J operates the pump 5 under predetermined test operation conditions. The hot and cold water in the circulation flow path 2 is pumped by the pump 5 and circulated. The predetermined test operation conditions are the same as the predetermined test operation conditions in step 101 shown in FIG. 3.

Next, the state determination unit C1J proceeds to step S122 shown in FIG. 4, and stores the signal output by the flow measurement unit 10 in the memory unit C1M as the post-replacement signal SG2.

Then, the state determination unit C1J proceeds to step S131 and determines whether the post-replacement signal SG2 is greater than the upper limit value G1H (G1HA or G1HB). If the answer is "Yes" in step S131, the state determination unit C1J proceeds to step S137. On the other hand, if the answer is "No" in step S131, the state determination unit C1J proceeds to step S132.

When the process moves from step S131 to step S132, the state determination unit C1J determines whether the post-replacement signal SG2 is smaller than the lower limit value G1L (G1LA or G1LB). If the answer is "Yes" in step S132, the process moves to step S134. On the other hand, if the answer is "No" in step S132, the process moves to step S133.

When the process moves from step S132 to step S133, the state determination unit C1J determines that the replaced flow measurement unit 10 is in a normal state, that is, the replaced flow measurement unit 10 is not broken, and the measurement specifications of the flow measurement unit 10 are the same before and after the replacement work. Then, the state determination unit C1J ends the second program.

When the process moves from step S132 to step S134, the state determination unit C1J determines whether the post-replacement signal SG2 is smaller than the threshold value G2. If the result is "Yes" in step S134, the process moves to step S135. On the other hand, if the result is "No" in step S134, the process moves to step S137.

When the process proceeds from step S131 or step S134 to step S137, the state determination unit C1J determines that a first error has occurred in which the measurement specifications of the flow measurement unit 10 are different before and after the replacement work.

Next, the state determination unit C1J proceeds to step S138 and causes the notification unit C1N to issue a first notification corresponding to the first error. The notification unit C1N controls the display unit 82 of the remote control 80 to display an error message as the first notification, for example, "The measurement specifications of the flow measurement unit 10 are different before and after the replacement work."

Then, the state determination unit C1J ends the second program. The replacement worker who has confirmed the first notification can quickly perform the task of replacing the incorrect flow measurement unit 10 (one of the first flow measurement unit 10A and the second flow measurement unit 10B) with the correct flow measurement unit 10 (the other of the first flow measurement unit 10A and the second flow measurement unit 10B).

When the process moves from step S134 to step S135, the state determination unit C1J determines that a second error has occurred, which indicates that the replaced flow measurement unit 10 has failed.

Then, the state determination unit C1J proceeds to step S136 and causes the notification unit C1N to issue a second notification corresponding to the second error, rather than the first notification. The notification unit C1N controls the display unit 82 of the remote control 80 to display an error message notifying the user of a malfunction of the flow measurement unit 10 as the second notification.

Then, the status determination unit C1J ends the second program. The replacement worker who confirmed the error message can quickly replace the faulty flow measurement unit 10 with a normal flow measurement unit 10.

<Action and effect>
In the hot water heater 1 of the embodiment, the state determination unit C1J stores a post-installation signal SG1 (SG1A or SG1B) in the memory unit C1M when the installation work is completed in the post-installation check process (steps S101 and S102 shown in FIG. 3). The post-installation signal SG1 corresponds to the length of the circulation flow path 2 according to the installation location of the hot water heater 1, and accurately reflects the measurement specifications after the flow measurement unit 10 is installed, i.e., before replacement.

Next, in the reference range setting process (step S111 shown in FIG. 3), the state determination unit C1J sets the upper limit value G1H (G1HA or G1HB) and the lower limit value G1L (G1LA or G1LB) by adding a predetermined allowable error T1 to the post-installation signal SG1 (SG1A or SG1B).

Next, in the post-replacement check process (steps S121 and S122 shown in FIG. 4), the state determination unit C1J stores the post-replacement signal SG2 in the memory unit C1M when the replacement work of the flow measurement unit 10 is completed.

Next, in the judgment process (steps S131 to S138 shown in FIG. 4), the state judgment unit C1J uses the upper limit value G1H (G1HA or G1HB) and the lower limit value G1LG1L (G1LA or G1LB) based on the post-installation signal SG1 to compare with the post-replacement signal SG2 to judge whether the measurement specifications of the flow measurement unit 10 are different before and after the replacement work.

In other words, the state determination unit C1J uses the post-installation signal SG1, which corresponds to the length of the circulation flow path 2 according to the installation location of the water heater 1 and accurately reflects the measurement specifications after installation of the flow measurement unit 10, i.e., before replacement, to determine the flow measurement unit 10, thereby improving the determination accuracy compared to a case in which the measurement specifications at the time of design of each flow measurement unit 10, i.e., the first flow measurement unit 10A and the second flow measurement unit 10B, are pre-stored in the memory unit C1M and used to determine the flow measurement unit 10.

The water heater 1 of the embodiment can therefore accurately determine whether the measurement specifications of the flow measurement unit 10 are different before and after replacement work. As a result, if it is determined that the measurement specifications of the flow measurement unit 10 in this water heater 1 are different before and after replacement work, the replacement worker can quickly replace the incorrect flow measurement unit 10 (one of the first flow measurement unit 10A and the second flow measurement unit 10B) with the correct flow measurement unit 10 (the other of the first flow measurement unit 10A and the second flow measurement unit 10B).

In addition, in this water heater 1, the memory unit C1M pre-stores a threshold value G2 that is lower than the respective lower limit values G1L (G1LA, G1LB) of the first flow measurement unit 10A and the second flow measurement unit 10B and greater than zero. Then, in the judgment process (steps S131 to S138 shown in FIG. 4), if the post-replacement signal SG2 is smaller than the threshold value G2, the state judgment unit C1J judges that a second error has occurred, in which the post-replacement flow measurement unit 10 has failed, and causes the alarm unit C1N to issue a second alarm corresponding to the second error, rather than the first alarm.

With this configuration, the state determination unit C1J can distinguish between the occurrence of a first error and the occurrence of a second error in the determination process (steps S131 to S138 shown in FIG. 4), and if it determines that a first error has occurred, it can cause the notification unit C1N to issue a first notification, and if it determines that a second error has occurred, it can cause the notification unit C1N to issue a second notification. This allows the water heater 1 to more accurately determine whether the measurement specifications of the flow measurement unit 10 are different before and after the replacement work and notify the replacement worker, as well as distinguish between a state in which the flow measurement unit 10 has failed after replacement and notify the replacement worker. As a result, it is possible to improve convenience for the replacement worker.

Although the present invention has been described above with reference to examples, it goes without saying that the present invention is not limited to the above examples and can be modified as appropriate without departing from the spirit of the invention.

In the embodiment, the flow rate measurement unit 10 is selected from two flow rate measurement units 10 having different measurement specifications, i.e., a first flow rate measurement unit 10A and a second flow rate measurement unit 10B, and is attached to the first internal pipe 31, but the present invention is not limited to this configuration. The flow rate measurement unit may be selected from three or more flow rate measurement units having different measurement specifications and attached to the flow path.

In the embodiment, the impeller of the flow rate measuring unit 10 is rotatable around a rotation axis parallel to the direction in which the internal flow path extends, but the present invention is not limited to this configuration. For example, the flow rate measuring unit may have an impeller that is rotatable around a rotation axis perpendicular to the direction in which the internal flow path extends. In addition, the flow rate measuring unit is not limited to an impeller type, and may be various types of flow meters such as a float type, ultrasonic type, or electromagnetic type. The signal of the flow rate measuring unit is also not limited to a pulse signal, and may be an analog signal such as an increasing or decreasing voltage value or current value, or a digital signal indicating a numerical value.

In the embodiment, the fluid circulation device is a water heater 1, but the present invention is not limited to this configuration. The fluid circulation device may be any type of fluid circulation device as long as it is a stationary type, and may be, for example, a heating device that circulates hot water, or a temperature adjustment device that circulates a heat transfer medium or a refrigerant.

The present invention can be used, for example, in residential equipment such as water heaters and heating devices that circulate hot water, and in factory equipment such as temperature control devices that circulate a heat transfer medium or refrigerant.

1...Fluid circulation device (hot water heater)
2...Flow path (circulation flow path)
5... Pump 10 (10A, 10B)... Flow rate measuring unit (10A... first flow rate measuring unit, 10B... second flow rate measuring unit)
C1M: Memory section C1J: Status determination section C1N: Notification section SG1: Post-installation signal S101, S102: Post-installation check process T1: Predetermined allowable error G1H: Upper limit G1L: Lower limit S111: Reference range setting process SG2: Post-replacement signal S121, S122: Post-replacement check process S131 to S138: Determination process G2: Threshold value

Claims (2)

A flow path for circulating a fluid;
a pump provided in the flow path for pumping the fluid;
a flow rate measuring unit that outputs a signal corresponding to a flow rate of the fluid flowing through the flow path, the flow rate measuring unit being attached to the flow path by selecting any one of a plurality of flow rate measuring units each having a different measurement specification, which is a correlation between the flow rate and the signal;
A storage unit that stores at least the signal;
A state determination unit that determines a state of the flow rate measurement unit;
A notification unit that issues a notification;
A stationary fluid circulation device comprising:
The state determination unit is
a post-installation check process in which, when the installation work of the fluid circulation device is completed, the pump is operated under a predetermined test operation condition, and the signal output by the flow rate measurement unit is stored in the memory unit as a post-installation signal;
a reference range setting process for setting an upper limit value and a lower limit value by taking into account a predetermined allowable error in the post-installation signal stored in the storage unit;
a post-replacement check process in which, when the replacement work of the flow rate measuring unit is completed, the pump is operated under the test operation conditions and the signal output by the flow rate measuring unit is stored in the memory unit as a post-replacement signal;
a determination process for determining that a first error has occurred in which the measurement specifications of the flow rate measurement unit are different before and after the replacement work when the post-replacement signal is greater than the upper limit value or less than the lower limit value, and forcing the notification unit to issue a first notification corresponding to the first error;
A fluid circulation device configured to carry out the steps of: The storage unit pre-stores a threshold value that is lower than the lower limit value of each of the flow rate measuring units and is greater than zero,
The fluid circulation device of claim 1, wherein, when the post-replacement signal is smaller than the threshold value in the judgment process, the status judgment unit judges that a second error has occurred, in which the flow measurement unit after replacement has failed, and causes the notification unit to issue a second notification corresponding to the second error instead of the first notification.

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