JP7702366B2 - Hot water system - Google Patents

Description

The present invention relates to a hot water supply system that is equipped with a hot water storage tank, a water supply tank, a pump, etc., and supplies hot water to hot water terminals such as showers and faucets.

Conventionally, in a hot water supply system, in order to be able to supply a sufficient amount of hot water even when multiple hot water taps (hot water outlet terminals) such as showers and faucets are used simultaneously, a hot water supply system is known that includes a heating heat source, a hot water storage tank for storing hot water heated by the heating heat source, a water supply tank for storing water from the water supply source, a pump for supplying water from the water supply tank and hot water from the hot water storage tank to the hot water tap, a water supply pipe for supplying water from the water supply source to the water supply tank, and a water supply valve for opening and closing the water passage of the water supply pipe (Patent Document 1).

Special Publication No. 59-18613

In the above-mentioned hot water supply system, assuming that the flow rate at the hot water outlet terminal such as the shower increases and the flow rate of water outflowing from the water supply tank increases, it is possible to increase the size of the water supply pipe that supplies water to the water supply tank to prevent the water tank from running out. In this case, when supplying water to the water supply tank, if the flow rate outflowing from the water supply tank, i.e., the flow rate of water used at the hot water outlet terminal, is low, the water supply flow rate to the water supply tank will be high, and the difference between the water supply flow rate and the flow rate of use will increase, which can cause large fluctuations in the water level in the water supply tank. As a result, the water supply valve will open and close frequently, which can cause problems such as reduced durability of the water supply valve.

The present invention was made in consideration of the above circumstances, and aims to provide a hot water supply system that has a water supply valve in a water supply passage that supplies water from a water source to a water supply tank, and that can improve the durability of the water supply valve while preventing the water supply tank from running out of water.

The hot water supply system according to the present invention comprises:
A heating source;
A hot water storage tank for storing hot water heated by a heating source;
A water tank for storing water from a water supply source;
A pump that supplies hot water from the hot water storage tank and water from the water supply tank to the hot water outlet terminal;
a water supply line for supplying water from a water supply source to a water supply tank;
A water supply valve for opening and closing the water supply passage;
A control device,
The water supply passage is provided in plurality,
The water supply valve is provided in each of the plurality of water supply passages,
A flow rate detection means is provided to detect the flow rate of the hot water used at the hot water outlet terminal;
The control device is configured to perform control to change the number of water supply valves to be opened in accordance with the flow rate used at the hot water supply terminal when water is supplied to the water supply tank through the water supply line.

According to the above configuration, when supplying water to the water tank, the number of water supply valves that are opened is changed depending on the flow rate used at the hot water outlet terminal, thereby reducing the difference between the water supply flow rate to the water tank and the flow rate used at the hot water outlet terminal, thereby reducing fluctuations in the water level in the water tank, and therefore reducing the number of times each water supply valve is opened and closed. In addition, since multiple water supply channels with water supply valves are provided, when the flow rate used at the hot water outlet terminal is high, the number of water supply valves that are opened can be increased, ensuring a greater water supply flow rate for the water tank. Therefore, even when the flow rate used at the hot water outlet terminal is high, it is possible to prevent the water tank from running out of water, and improve the durability of the water supply valves.

In the hot water supply system,
The control device can be configured to store the previously opened water supply valve, and the next time the water supply valve is opened, perform control to open a water supply valve other than the stored water supply valve.

According to the above configuration, the water supply valve that is opened can be changed each time water is supplied to the water tank, which reduces bias in the water supply valves used and further improves the durability of the water supply valves.

In the hot water supply system,
A Lo water level detection means is provided for detecting when the water level of the water supply tank falls below a predetermined Lo water level,
The control device can be configured to control the multiple water supply valves to open when the Lo water level detection means detects a water level below the Lo water level during water supply to the water supply tank, even if the flow rate used at the water outlet terminal is less than a predetermined amount.

When the Lo water level detection means detects a water level below the Lo water level, the amount of water stored in the water supply tank is low, and it can be said that the water supply tank is approaching a drought state. According to the configuration of the present invention, when the Lo water level detection means detects a water level below the Lo water level, even if the flow rate used at the hot water outlet terminal is below a predetermined amount, the water supply flow rate to the water supply tank can be increased by opening multiple water supply valves, thereby reliably preventing drought in the water supply tank. Note that detection of a water level below the Lo water level also includes detection for a predetermined period of time.

1 is a schematic configuration diagram illustrating an example of a hot water supply system according to an embodiment. 2 is a schematic diagram showing a configuration of a water supply tank included in the hot water supply system according to the embodiment; FIG. 10 is a flowchart showing a process for starting a water supply operation to the water tank. 4 is a flowchart showing a process for controlling the operation of a water supply valve. 13 is a flowchart showing the process of determining whether multiple units are open when water is supplied through multiple water supply pipes.

Hereinafter, a hot water supply system according to an embodiment of the present invention will be described.
The hot water supply system A of the embodiment shown in FIG. 1 is a hot water supply system that can be used in commercial facilities such as hairdressing salons, and is configured to be able to supply a large amount of water or hot water from the hot water supply pressurized tank unit 1 to hot water outlet terminals 400 such as multiple showers and faucets that serve as hot water taps. The heat source unit 500 has a first gas heat source unit 501 and a second gas heat source unit 502 that are heating heat sources. Note that as the heating heat source, one or three or more gas heat source units may be included, and a heat pump or an electric heater may be used instead of the gas heat source unit. The hot water supply pressurized tank unit 1 includes a water supply tank 2 that stores water supplied from a water supply source, and a hot water storage tank 6 that stores hot water heated by the heat source unit 500, and is able to supply a large amount of hot water to the hot water outlet terminal 400. In addition, the hot water supply pressurized tank unit 1 has an outside air temperature sensor 80 that detects the outside air temperature at the bottom of the housing.

The first and second gas heat source units 501, 502 are gas water heaters, and although not shown, are equipped with a gas burner, a heat exchanger, and a heat source unit control device that controls the operation of the heating heat source within the housing. The first and second gas heat source units 501, 502 and the hot water storage tank 6 are connected by a heating circulation circuit consisting of a heating forward pipe 40 that sends hot water from the hot water storage tank 6 and water from the water supply tank 2 to the first and second gas heat source units 501, 502, and a heating return pipe 44 that returns the hot water heated by the first and second gas heat source units 501, 502 to the hot water storage tank 6.

The heating forward pipe 40 is branched into a first heating forward pipe 41 and a second heating forward pipe 42 midway so that one end is connected to the bottom of the hot water storage tank 6 and the other end is connected to the first gas heat source unit 501 and the second gas heat source unit 502. The heating return pipe 44 is formed by joining a first heating return pipe 45 and a second heating return pipe 46, one end of which is connected to each gas heat source unit 501, 502, midway, and the other end is connected to the top of the hot water storage tank 6.

The heating return pipe 44 is provided with an automatic air vent valve 57 that opens when the pressure in the hot water tank 6 rises above a predetermined value, and a heating return temperature sensor 58 that detects the temperature of the hot water flowing into the hot water tank 6. The heating forward pipe 40 is also connected to the water supply forward pipe 3, and a tank temperature sensor 55 that detects the temperature of the hot water supplied from the hot water tank 6 to the heating forward pipe 40 and a manually opened/closed valve 56 (which may be a valve that is opened and closed by the control device C) are provided upstream of the junction with the water supply forward pipe 3. A heating forward temperature sensor 50 is provided downstream of the junction with the water supply forward pipe 3 and upstream of the branching point of the first and second heating forward pipes 41, 42 in the heating forward pipe 40. A first heating circulation pump 51 and a second heating circulation pump 52 are provided in the first and second heating supply pipes 41 and 42, respectively, and check valves 53 and 54 are provided downstream of the first and second heating circulation pumps 51 and 52. By operating the first and second heating circulation pumps 51 and 52 and the first and second gas heat source units 501 and 502, hot water at a predetermined hot water outlet temperature heated by the first and second gas heat source units 501 and 502 is supplied to the hot water storage tank 6.

The hot water tank 6 is made of a metal (e.g., stainless steel) with excellent corrosion resistance, and although not shown, the outer periphery is covered with a heat insulating material. The capacity of the hot water tank 6 in this embodiment is, for example, 50 liters. The lower part of the hot water tank 6 is connected to a heating supply pipe 40 and a hot water return pipe 72 that returns hot water from the hot water outlet terminal 400, and the upper part of the hot water tank 6 is connected to a heating return pipe 44 and a hot water supply supply pipe 71 that is connected to the hot water outlet terminal 400. The hot water tank 6 is provided with a first hot water temperature sensor 61, a second hot water temperature sensor 62, and a third hot water temperature sensor 63, which are installed from the top at a predetermined interval, in that order to detect the temperature of the hot water stored inside.

The water supply tank 2 is disposed above the hot water storage tank 6 and supplies water to the hot water terminal 400, the hot water storage tank 6, the gas heat source units 501 and 502, etc. The capacity of the water supply tank 2 in this embodiment is, for example, 70 liters. Although not shown, the water supply tank 2 is partially open to the atmosphere. Two first and second water supply pipes 11 and 12 (multiple water supply lines) branching from the water supply pipe 10 that supplies the city water of the water supply source to the water supply tank 2 are connected to the upper part of the water supply tank 2, and the water supply outgoing pipe 3 is connected to the lower part of the water supply tank 2. Note that in Figures 1 and 2, the first and second water supply pipes 11 and 12 are described as being arranged above and below the water supply tank 2 for the sake of explanation, but in reality they are arranged at the same height above the water supply tank 2. The first and second water supply pipes 11 and 12 are respectively provided with a first governor 13, a second governor 14, a first water supply valve 15 and a second water supply valve 16, in that order from the upstream side. The first and second water supply valves 15 and 16 are configured as solenoid valves that open and close. The first and second water supply valves 15 and 16 are connected to a control device C, and are controlled to open and close by a control signal from the control device C. In this way, by connecting multiple water supply pipes (first and second water supply pipes 11 and 12) to the water supply tank 2, pressure loss can be reduced and water can be supplied to the water supply tank 2 in a short time. In addition to being configured by branching off from the water supply pipe 10, the first and second water supply pipes 11 and 12 may be configured by multiple water supply pipes drawn in parallel from a water supply source.

Referring also to FIG. 2, the water supply tank 2 has a drain outlet 21 on one side wall below the connection ports of the first and second water supply pipes 11, 12 and above the connection port of the water supply forward pipe 3, and an overflow pipe 9 is connected to the inside of the water supply tank 2 of this drain outlet 21. A drain pipe 200 is connected to the outside of the water supply tank 2 of the drain outlet 21 (see FIG. 1). On the other side wall of the water supply tank 2, an overflow float sensor 22, a Hi float sensor 23, a Lo float sensor 24, and a low water level float sensor 25 are arranged at predetermined intervals in this order from the top as water level detection means for detecting the water level in the water supply tank 2.

The overflow pipe 9 is a tubular member that drains excess water in the water supply tank 2 when the water level in the water supply tank 2 exceeds a predetermined height, and is installed in the water supply tank 2 (see Figures 1 and 2). One end of the overflow pipe 9 is an upstream end opening 91 that communicates with the inside of the water supply tank 2, and the other end is connected to the drainage port 21 of the water supply tank 2. The overflow pipe 9 is provided with an overflow hole 92 that communicates with the inside of the water supply tank 2 at the upper part near the upstream end opening 91. Therefore, excess water in the water supply tank 2 flows into the overflow pipe 9 from the overflow hole 92 or the upstream end opening 91 and is discharged to the outside. The diameter is set so that the amount of water flowing in from the upstream end opening 91 is greater than the maximum water supply flow rate from the first and second water supply pipes 11 and 12, and the diameter is set so that the amount of water flowing in from the overflow hole 92 is less than the amount of water flowing in from the upstream end opening 91. The overflow pipe 9 is formed in a roughly U-shape, and the entire curved portion at the bottom forms a trap section 93 that collects and seals a portion of the drainage water. This trap section 93 prevents odors and germs from entering from the downstream side. The overflow pipe 9 may be installed outside the water supply tank 2. In this case, the portion on the upstream end opening 91 side is bent into an L-shape to connect to the drain outlet 21 from the outside of the water supply tank 2, and a straight connecting pipe is connected horizontally to the overflow hole (92) so that it communicates with the inside of the water supply tank 2 at the height of the overflow hole (92).

When the water level in the water supply tank 2 rises to a height that submerges a float built into the sensor, the float moves and each float sensor 22-25 turns ON, and when the water level in the water supply tank 2 falls and the float is no longer submerged, the water level drops and the float moves in the opposite direction and turns OFF. In other words, each float sensor 22-25 detects when the water level (storage water volume) in the water supply tank 2 has reached the water level at the sensor position by turning ON, and detects when the water level (storage water volume) in the water supply tank 2 has fallen below the water level at the sensor position by turning OFF. The low water level detected by the low water level float sensor 25 is set, for example, to a 15 liter position in terms of the amount of water stored in the water tank 2, the Lo water level detected by the Lo float sensor 24 is set, for example, to a 45 liter position in terms of the amount of water stored in the water tank 2, the Hi water level detected by the Hi float sensor 23 is set, for example, to a 60 liter position in terms of the amount of water stored in the water tank 2, and the overflow water level detected by the overflow float sensor 22 is set, for example, to a 64 liter position in terms of the amount of water stored in the water tank 2.

The height position relationship between each float sensor 22-25 in the water supply tank 2 and the overflow pipe 9 is as follows: the low water level float sensor 25 is disposed at a height position lower than the overflow pipe 9, the Lo float sensor 24 is disposed at a height position slightly higher than the trap section 93 at the bottom of the overflow pipe 9, the Hi float sensor 23 is disposed near the overflow hole 92 at a height position slightly higher than the overflow hole 92, and the overflow float sensor 22 is disposed near the upstream end opening 91 at a height position slightly lower than the upstream end opening 91. The detection signal of the water level detected by each float sensor 22-25 is output to the control device C. Note that the means for detecting the water level of the water supply tank 2 is not limited to the float sensors 22-25, and other contact type water level gauges such as capacitance type or non-contact type water level gauges such as ultrasonic type may be used.

The water supply pipe 3 branches upstream into a first water supply pipe 31 and a second water supply pipe 32 so that water flows in parallel. A water supply booster pump 37 is installed upstream of the branch between the first water supply pipe 31 and the second water supply pipe 32. This water supply booster pump 37 constitutes a pump that supplies hot water stored in the hot water storage tank 6 and water stored in the water supply tank 2 to the hot water outlet terminal 400.

The first water supply pipe 31 is provided with a check valve 33 and a pressure sensor 35 for detecting water pressure, in that order from the upstream side, and the second water supply pipe 32 is provided with a check valve 34 and a water flow sensor (flow rate detection means) 36 for detecting the water flow rate, in that order from the upstream side. It is also possible to provide a pressure sensor and a water flow sensor in a single water passage without providing parallel water passages such as the first and second water supply pipes 31 and 32, but it is possible to reduce pressure loss in the water supply pipe 3 by forming parallel water passages by the first water supply pipe 31 and the second water supply pipe 32 so that water flows in parallel and providing a pressure sensor and a water flow sensor in each water passage. The water flow rate may differ in each of the first and second water supply pipes 31 and 32, but if the ratio of pressure loss is known, the water flow rate of the entire water supply pipe 3 can be calculated from the water flow rate detected by the water flow sensor 36. The detection signal of the detected pressure detected by the pressure sensor 35 and the detection signal of the detected flow rate detected by the water volume sensor 36 are output to the control device C.

The first water supply pipe 31 and the second water supply pipe 32 join at a junction downstream of the pressure sensor 35 and the water volume sensor 36, and the other end of the water supply pipe 3 is connected to a junction with a heating pipe 40 connected to the lower part of the hot water tank 6. The water supply pipe 3 branches into a water supply branch pipe 38 connected to the hot water outlet terminal 400 downstream of the junction of the first and second water supply pipes 31 and 32. The downstream side of the water supply branch pipe 38 branches into multiple parts depending on the number of showers and faucets of the hot water outlet terminal 400. A check valve 39 is interposed in the water supply pipe 3 downstream of the branch of the water supply branch pipe 38. The water supply pipe 3, including the first and second water supply pipes 31 and 32 and the water supply branch pipe 38, constitutes a water supply circuit.

One end of the hot water return pipe 72 is connected to the bottom of the hot water storage tank 6, and the other end is connected to the hot water supply pipe 71 at the hot water discharge terminal 400. An instant hot water circulation pump 73 is installed in the hot water return pipe 72, and an instant hot water return temperature sensor 74 and a check valve 75 are installed downstream of the instant hot water circulation pump 73. The hot water supply pipe 71 and the hot water return pipe 72, which are arranged between the hot water storage tank 6 and the hot water discharge terminal 400, form an instant hot water circulation circuit.

In this hot water supply system A, the usage flow rate of hot water at the hot water outlet terminal 400 is equal to the outflow flow rate of the water supply tank 2 flowing out to the water supply forward pipe 3, and is the detected flow rate by the water volume sensor 36. In other words, the usage flow rate at the hot water outlet terminal 400 is the total flow rate of the water flowing in the water supply forward pipe 3, which is divided at the branch and supplied from the water supply branch pipe 38, and the hot water flowing out of the hot water storage tank 6 by water entering from the water supply forward pipe 3 and supplied through the hot water supply forward pipe 71, which is originally the flow rate of water flowing out of the water supply tank 2 and flowing through the water supply forward pipe 3. The flow rate of water flowing through the water supply forward pipe 3 is detected by the water volume sensor 36. Therefore, the usage flow rate of the hot water outlet terminal 400 is also the outflow flow rate of the water supply tank 2, and is the detected flow rate of the water volume sensor 36. The detection of the flow rate used at the hot water outlet terminal 400 is not limited to the water volume sensor 36, but may be performed, for example, by a water volume sensor provided in each of the water supply branch pipe 38 and the hot water supply supply pipe 71, or may be performed by a water volume sensor provided in the hot water outlet terminal 400.

The hot water supply system A is equipped with a remote control R that allows the user to perform operations related to the operation of the hot water supply system A. The remote control R is connected by wire or wirelessly so as to be able to communicate with the control device C and the heat source device control devices (not shown) provided in the first and second gas heat source units 501, 502.

The remote control R is a terminal device configured to instruct the control device C on operation information such as turning the power of the hot water supply system A on and off, and setting the hot water storage temperature in the hot water storage tank 6 (such as the outlet temperature of the hot water discharged from the first and second gas heat source units 501, 502) in response to the user's operation of an operation switch (not shown). The remote control R is equipped with a display that displays various information about the hot water supply system A. Note that instead of or together with the remote control R, a mobile terminal such as a smartphone or tablet terminal connected to the control device C so as to be able to communicate with it can be used.

The control device C is composed of one or more electronic circuit units including a CPU, ROM, RAM, interface circuit, etc. The memory stores various data such as various operation programs and setting values for executing the operation programs, and also stores the history of the water supply valves in use (first or second water supply valves 15, 16). Detection signals from the various sensors and valves described above are input to the control device C, and operation information is input from the remote control R. The control device C controls the operation of the entire hot water supply system A by controlling the operation of the gas heat source units 501, 502, the various pumps 37, 51, 52, 73, the water supply valves 15, 16, etc.

To summarize the main operational control by the control device C, when the hot water outlet terminal 400 is opened, the water supply pressure pump 37 is operated to supply water stored in the water supply tank 2 to the hot water outlet terminal 400 via the water supply forward pipe 3 and the water supply branch pipe 38, and water from the water supply tank 2 is supplied to the lower layer of the hot water storage tank 6 via the water supply forward pipe 3 and the heating forward pipe 40 below the tank, so that hot water from the upper layer of the hot water storage tank 6 is supplied to the hot water outlet terminal 400 via the hot water forward pipe 71 (hot water outlet operation). In addition, when the temperature detected by the third storage temperature sensor 63 installed at the bottom of the hot water storage tank 6 falls below a predetermined hot water storage start temperature, the first and second heating circulation pumps 51, 52 are operated to supply hot water from the bottom of the hot water storage tank 6 to the first and second gas heat source units 501, 502 through the heating forward pipe 40 and the first and second heating forward pipes 41, 42, and the hot water heated to a predetermined hot water outlet temperature by the first and second gas heat source units 501, 502 is supplied to the top of the hot water storage tank 6 through the first and second heating return pipes 45, 46 and the heating return pipe 44 (hot water storage operation). In addition, when the temperature of the hot water remaining in the hot water supply forward pipe 71 and the hot water supply return pipe 72 drops due to the passage of a predetermined instant hot water start time, the instant hot water circulation pump 73 is operated to send the hot water stored in the hot water storage tank 6 to the hot water supply forward pipe 71 (instant hot water operation). In addition, when the amount of water stored in the water supply tank 2 becomes low, water from the water supply source is supplied to the water supply tank 2 via the water supply pipe 10 (water supply operation).

Next, a characteristic configuration of the present invention will be described.
That is, in the hot water supply system A of this embodiment, two water supply pipes, a first water supply pipe 11 and a second water supply pipe 12, a first water supply valve 15 and a second water supply valve 16 are provided corresponding to the first water supply pipe 11 and the second water supply pipe 12, respectively, and the control device C is characterized by performing control to change the number of water supply valves to be opened according to the flow rate used at the hot water dispensing terminal 400 when water is supplied to the water supply tank 2 by the first and second water supply pipes 11, 12. Note that in the present invention, the number of water supply pipes is not limited to two, and three or more may be provided, and in this case, a water supply valve is also provided on each of the multiple water supply pipes.
The operation of supplying water to the water tank 2 will be described below.

To start the water supply operation to the water supply tank 2, the control device C first performs the following water supply operation start process. Referring to the flowchart in Figure 3, the control device C monitors the output of each float sensor 22-24 and determines whether the Hi float sensor 23 and the overflow float sensor 22 are OFF (step S01). If the Hi float sensor 23 and the overflow float sensor 22 are both OFF ("YES" in step S01), it then determines whether the Lo float sensor 24 is ON (step S02). In other words, it checks from the output of the Lo float sensor 24 whether the water level in the water supply tank 2 is above the Lo water level. If the Lo float sensor 24 is ON ("YES" in step S02), that is, if the water level in the water supply tank 2 is equal to or higher than the Lo water level, it is determined whether the accumulated amount of water used at the water supply terminal 400 is equal to or higher than a predetermined accumulated amount QA (e.g., 10 liters) (step S03), and if it is equal to or higher than the predetermined accumulated amount QA ("YES" in step S03), it issues an instruction to start the water supply operation (step S04). Here, the accumulated amount of water used at the water supply terminal 400 is the accumulated value of the flow rate (L/min) used at the water supply terminal 400 from the time when the Hi float sensor 23 is OFF to the time of this determination (step S03). The flow rate used at the water supply terminal 400 is the detected flow rate detected by the water volume sensor 36 installed in the water supply forward pipe 32. The accumulated value is cleared when the Hi float sensor 23 detects ON.

On the other hand, if the Lo float sensor 24 is not ON in step S02 ("NO" in step YS2), that is, if the Lo float sensor 24 is OFF and the water level in the water supply tank 2 is below the Lo water level, the start of water supply operation is instructed without determining the accumulated amount of usage at the water outlet terminal 400 (step S04).
In response to the above-mentioned command to start the water supply operation, the control device C performs processing to control the operation of the water supply valve.

In the water supply valve operation control, referring to the flow chart of FIG. 4, the control device C first judges whether or not there has been a water supply experience to the water supply tank 2 in the past (step S1). If there has been no water supply experience (step S1: NO), the control device C opens the first water supply valve 15 (step S2). In addition, the control device C stores the first water supply valve 15 in the history data as the most recently used water supply valve (step S3). On the other hand, if there has been a water supply experience (step S1: YES), the control device C refers to the stored history data and judges whether or not the water supply valve in use indicating the water supply valve (15 or 16) that was opened last time was the first water supply valve 15 (step S4). If the water supply valve in use last time was not the first water supply valve 15 (step S4: NO), the control device C opens the first water supply valve 15 (step S2) and also stores the first water supply valve 15 in the history data as the most recently used water supply valve (step S3). If the previously used water supply valve was the first water supply valve 15 ("YES" in step S4), the control device C opens the second water supply valve 16 (step S5) and also stores the second water supply valve 16 in the historical data as the most recently used water supply valve (step S6).
By the above operation, first, one water supply valve (15 or 16) is opened, and water from the water supply source is supplied to the water supply tank 2 from one water supply pipe (11 or 12).

Next, the control device C advances the process to step S7, and determines whether or not water is to be supplied to the water supply tank 2 through the two water supply pipes (two-unit open determination).
In this two-unit open determination, the control device C determines whether the usage flow rate at the hot water supply terminal 400 is equal to or greater than a predetermined amount Q (e.g., 20 L/min) by referring to the flowchart in Fig. 5 (step S71). If the usage flow rate at the hot water supply terminal 400 is equal to or greater than the predetermined amount Q ("YES" in step S71) at the time of this determination, the control device C determines whether the currently open water supply valve is the first water supply valve 15 (step S72), and if the first water supply valve 15 is currently open ("YES" in step S72), the control device C opens the second water supply valve 16 (step S73). In addition, the control device C stores the second water supply valve 16 in the history data as the most recently used water supply valve (step S74). If the currently open water supply valve is not the first water supply valve 15 ("NO" in step S72), the first water supply valve 15 is opened (step S75), and the first water supply valve 15 is also stored in the history data as the most recently used water supply valve (step S76).
By the above operation, the first and second water supply valves 15, 16 are opened, whereby water from the water supply source is supplied to the water supply tank 2 from the two water supply pipes, the first and second water supply pipes 11, 12.

On the other hand, if the flow rate used at the hot water supply terminal 400 is less than the predetermined amount Q in step S71, the control device C judges whether the Lo float sensor 24 has remained OFF for a predetermined time T (e.g., 20 seconds) when it was OFF (step S77). This judgment process is performed when the instruction to start the water supply operation is given by the Lo float sensor 24 being OFF (if "NO" in step S02 in Figure 3), and is mainly a process to judge whether the water level in the water supply tank 2 has risen slowly and has not reached the Lo water level within the predetermined time T, and the Lo float sensor 24 has not turned ON, despite one water supply valve being opened by the water supply valve operation control (Figure 4).

Then, in step S77, if the OFF state of the Lo float sensor 24 has not continued for the predetermined time T ("NO" in step S77), that is, if the water level in the water supply tank 2 has reached the Lo water level within the predetermined time T and the Lo float sensor 24 has turned ON, in this case, the control device C returns the process to step S71. Note that the process also returns to step S71 if the predetermined time T has not yet elapsed since the Lo float sensor 24 turned OFF, or if a command to start the water supply operation is executed when the Lo float sensor 24 is ON and the accumulated amount of use at the hot water supply terminal 400 is equal to or greater than the predetermined accumulated amount QA ("YES" in step S03 in FIG. 3). On the other hand, in step S77, if the Lo float sensor 24 has remained in the OFF state for the predetermined time T ("YES" in step S77), that is, as described above, the water level in the water supply tank 2 is rising slowly. In this case, the control device C transitions to step S72 and performs processing to open the water supply valves that are not currently open (steps S73 to S76), thereby supplying water to the water supply tank 2 from the two water supply pipes, the first and second water supply pipes 11, 12.
This completes the control of the opening operation of the water supply valve.

After the water supply valves are opened, the control device C performs a process to determine whether to close the water supply valves in order to stop the water supply. In this process, for example, when the overflow float sensor 22 or the Hi float sensor 23 is turned ON, or when a predetermined time (for example, about 3 to 20 seconds) has elapsed since the overflow float sensor 22 or the Hi float sensor 23 was turned ON, it is determined that the water supply stop condition is met, and all open water supply valves are closed. This ends the water supply operation to the water supply tank 2. If the determination in step S77 is "NO," the control device C performs a process to determine whether to close the water supply valves before returning the process to step S71. If the water supply stop condition is met, all open water supply valves are closed, and if the water supply stop condition is not met, the process returns to step S71. That is, if the flow rate used by the hot water supply terminal 400 is less than the predetermined amount Q, the process is repeated between steps S71 and S77 to prevent a situation in which the water supply is not stopped.

(Effects of the embodiment)
As described above, in this embodiment, when supplying water to the water supply tank 2, the number of water supply valves to be opened is changed to one or two depending on the flow rate of use at the hot water outlet terminal 400, so that the difference between the water supply flow rate to the water supply tank 2 and the flow rate of use at the hot water outlet terminal 400 is reduced, and the fluctuation in the water level in the water supply tank 2 can be reduced, thereby reducing the number of times the first and second water supply valves 15, 16 are opened and closed. In addition, by providing multiple water supply pipes 11, 12 and multiple water supply valves 15, 16, when the flow rate of use at the hot water outlet terminal 400 is greater than or equal to a predetermined amount Q, the number of water supply valves to be opened is increased, and both the first and second water supply valves 15, 16 are opened (steps S71, S72, S73, and S75 in FIG. 5), so that a larger water supply flow rate can be secured for the water supply tank 2. Therefore, even if the flow rate used at the hot water outlet terminal 400 is high, it is possible to prevent the water supply tank 2 from running out of water, and the durability of the first and second water supply valves 15, 16 can be improved.

In addition, in this embodiment, the history of the water supply valve that was opened immediately before the operation of supplying water to the water supply tank 2 is stored (steps S3 and S6 in FIG. 4, and steps S74 and S76 in FIG. 5), and the next time the water supply valve is opened, a water supply valve other than the stored water supply valve is opened (steps S4, S2, and S5 in FIG. 4). This makes it possible to change the water supply valve that is opened each time water is supplied to the water supply tank 2, thereby preventing bias in the water supply valves used and further improving the durability of the first and second water supply valves 15, 16.

When supplying water to the water tank 2, if the multiple water supply valves are opened from the beginning, if the flow rate used at the water outlet terminal 400 is low and below the predetermined amount Q, the water supply flow rate to the water tank 2 will be high relative to the flow rate used, and a certain amount of water will be stored in the water tank 2 quickly, so the water supply valves will close relatively quickly after opening. The next time water is supplied, if the flow rate used at the water outlet terminal 400 is low and below the predetermined amount Q, the multiple water supply valves will be opened and then closed relatively quickly. As a result, the multiple water supply valves will open and close frequently, reducing their durability.

In this embodiment, when supplying water to the water supply tank 2, one water supply valve is opened first (steps S4, S2, and S5 in FIG. 4), and then, if the flow rate used at the hot water outlet terminal 400 is equal to or greater than the predetermined amount Q (step S71 in FIG. 5, "YES"), control is performed to open the other water supply valves other than the one water supply valve (steps S72, S73, and S75 in FIG. 5). In this way, since the first and second water supply valves 15 and 16 are opened one by one, if the flow rate used at the hot water outlet terminal 400 is less than the predetermined amount Q (step S71 in FIG. 5, "NO"), if the water level in the water supply tank 2 has risen above the Lo water level (step S77 in FIG. 5, "NO"), the water supply operation is terminated when the water supply stop condition is met, so that the other water supply valves other than the first water supply valve are not used. In this case, since only one water supply valve is open, the water supply flow rate to the water supply tank 2 is not greater than the usage flow rate, and the difference between the water supply flow rate and the usage flow rate is reduced, which reduces fluctuations in the water level in the water supply tank 2, and the water supply valve is not closed relatively quickly after opening. Therefore, the first and second water supply valves 15, 16 do not open and close frequently, which improves the durability of the first and second water supply valves 15, 16.

On the other hand, if the usage flow rate at the hot water outlet terminal 400 is greater than or equal to the predetermined amount Q ("YES" in step S71 in FIG. 5), in addition to the first water supply valve that was opened, the other water supply valves are also opened (steps S73 and S75 in FIG. 5), so that a larger water supply flow rate can be secured for the water supply tank 2. Also, even if the water supply flow rate to the water supply tank 2 is increased, the usage flow rate at the hot water outlet terminal 400 is large, so the difference between the water supply flow rate and the usage flow rate does not increase, causing large fluctuations in the water level in the water supply tank 2. Therefore, the water supply valve is not closed relatively quickly after opening, and the first and second water supply valves 15 and 16 do not open and close frequently. Therefore, even if the usage flow rate at the hot water outlet terminal 400 is large, it is possible to prevent the water supply tank 2 from running out of water, and the durability of the first and second water supply valves 15 and 16 can be improved.

In addition, in this embodiment, even if the flow rate used at the hot water supply terminal 400 is less than the predetermined amount Q ("NO" in step S71 in FIG. 5) during the water supply operation to the water supply tank 2, if the OFF state of the Lo float sensor 24 continues for a predetermined time T (20 s) ("YES" in step S77 in FIG. 5), the first and second water supply valves 15 and 16 are both opened (steps S72, S73, and S75 in FIG. 5). If the Lo float sensor 24 is OFF, the water supply tank 2 is in a low water level state, and if the OFF state of the Lo float sensor 24 continues for the predetermined time T, it can be said that the water supply tank 2 is approaching a drought state. Therefore, with the above configuration, by opening both the first and second water supply valves 15 and 16, the water supply flow rate to the water supply tank 2 can be increased, and drought in the water supply tank 2 can be reliably prevented.

As described above, according to the hot water supply system A of this embodiment, in a configuration in which a water supply valve is provided on a water supply pipe that supplies water from a water supply source to the water supply tank 2, if multiple water supply pipes are provided in the water supply tank 2 and a water supply valve is provided on each of the multiple water supply pipes, it is possible to improve the durability of the water supply valve while preventing the water supply tank 2 from running dry.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims.
For example, in an embodiment, after both the first and second water supply valves 15, 16 are opened, the other water supply valve is not closed, but if the flow rate used at the hot water supply terminal 400 decreases to or below a predetermined amount Q after the two water supply valves 15, 16 are opened, the water supply valve that was opened first may be closed and only one water supply valve may be opened.

In addition, three or more water supply pipes and water supply valves may be provided. In this case, in the process of determining whether multiple water supply valves are open (corresponding to the process in FIG. 5), multiple thresholds (predetermined amount Q) for determining the magnitude of the flow rate used at the hot water supply terminal 400 may be set in stages, and the number of water supply valves to be opened may be increased as the flow rate used at the hot water supply terminal 400 increases, so that the number of water supply valves to be opened may be changed one by one according to the flow rate used. In this case, the history data stored as the water supply valves used during the water supply operation may store the history of the water supply valves that were opened in the order of their most recent use, and the next time the water supply valves are opened, they may be opened in order starting with the water supply valve that has not been used for the longest time in the history data.

In addition, when the water level in the water supply tank 2 drops below the low water level and the low water level float sensor 25 turns OFF, the control device C may simultaneously open the first and second water supply valves 15, 16 to immediately supply a large amount of water to the water supply tank 2, thereby preventing the water supply tank 2 from running dry. When all water supply valves are simultaneously opened in this manner, the water supply valves in use are not stored, and the history data is not updated.

In addition, a water leakage detection means 81 for detecting water leakage within the hot water pressure tank unit is provided at the bottom of the housing of the hot water pressure tank unit. If the water leakage detection means 81 detects water leakage within the hot water pressure tank unit during the water supply operation to the water supply tank 2, all open water supply valves may be closed to forcibly stop the water supply operation.

The overflow pipe 9 may also not have an overflow hole 92.

1 Hot water pressure tank unit 2 Water supply tank 3 Water supply pipe 6 Hot water storage tank 9 Overflow pipe 10 Water supply pipe (water supply line)
11 1st water supply pipe (supply waterway)
12 Second water supply pipe (supply waterway)
13 First governor 14 Second governor 15 First water supply valve 16 Second water supply valve 21 Drain port 22 Overflow float sensor 23 Hi float sensor 24 Lo float sensor (Lo water level detection means)
25 Low water level float sensor 31 First water supply pipe 32 Second water supply pipe 33 Check valve 34 Check valve 35 Pressure sensor 36 Water volume sensor (flow rate detection means)
37 Water supply booster pump 38 Water supply branch pipe 39 Check valve 71 Hot water supply forward pipe 72 Hot water supply return pipe 81 Leak detection means 91 Upstream end opening 92 Overflow hole 93 Trap section 200 Drain pipe 400 Hot water outlet terminal 500 Heat source unit A Hot water supply system C Control device R Remote control

Claims (3)

A heating source;
A hot water storage tank for storing hot water heated by a heating source;
A water tank for storing water from a water supply source;
A pump that supplies hot water from the hot water storage tank and water from the water supply tank to the hot water outlet terminal;
a water supply line for supplying water from a water supply source to a water supply tank;
A water supply valve for opening and closing the water supply passage;
A control device,
The water supply passage is provided in plurality,
The water supply valve is provided in each of the plurality of water supply passages,
A flow rate detection means is provided to detect the flow rate of the hot water used at the hot water outlet terminal;
The control device is a hot water supply system that performs control to change the number of water supply valves to be opened depending on the flow rate used at the hot water supply terminal when water is supplied to the water supply tank through the water supply line. The hot water supply system according to claim 1,
The hot water supply system, wherein the control device memorizes the previously opened water supply valve, and the next time the water supply valve is opened, performs control to open a water supply valve other than the memorized water supply valve. In the hot water supply system according to claim 1 or 2,
A Lo water level detection means is provided for detecting when the water level in the water supply tank falls below a predetermined Lo water level,
The control device is a hot water supply system in which, when the Lo water level detection means detects a water level below the Lo water level during water supply to the water tank, the control device controls multiple water supply valves to open even if the flow rate used at the hot water outlet terminal is less than a specified amount.

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