Storage tank type hot water supply device

Abstract

To provide a storage water heater capable of suppressing damage of an impeller type water amount sensor even in the case where air is stored in a hot water storage tank during stop of water supply and then a water faucet is opened after return to a normal state.SOLUTION: In a storage water heater 10 in which hot water in a hot water storage tank 12 is supplied to a first water faucet 13 at normal time, a hot water supply pipe 20 for sending hot water in the hot water storage tank 12 to the first water faucet 13 includes: a mixing valve C mixing the hot water from the hot water storage tank 12 with water in a water pipe 11; and an impeller type water amount sensor D that measures a flow rate of hot water flowing in the hot water supply pipe 20 on the downstream side of the mixing valve C. When the possibility of inflow of air to the hot water storage tank 12 along with delivery of hot water of the hot water storage tank 12 from a second water faucet 48 is detected and the first water faucet 23 is opened after return from stop of water supply to a normal state, control means for adjusting an opening of an inflow port C1 of hot water of the hot water storage tank 12 in the mixing valve C and an opening of an inflow port C2 of water in the water pipe 11 performs control for causing the opening of the inflow port C2 of the mixing valve C to become a predetermined opening J or larger.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a storage type hot water supply device that supplies hot water in a hot water tank to a water faucet. [Background technology]

[0002] A hot water storage type water heater supplies hot water (meaning hot water or cold water, the same applies below) made by mixing hot water from a hot water storage tank with water from a water pipe using a mixing valve to a water faucet installed in a kitchen or bathroom (see Patent Documents 1 and 2). Hot water is supplied to the faucet by utilizing the water pressure normally present in the water pipe, so there is no need to provide a pump to supply hot water to the faucet. Users can dispense hot water from the faucet by opening the faucet. In addition, as hot water is dispensed from the hot water storage tank, water is pumped from the water pipe into the hot water storage tank due to the water pressure of the water pipe. However, when a natural disaster or other incident causes the water supply infrastructure to fail, the flow of water in the water pipes stops, and there is no water pressure in the pipes, so hot or cold water cannot come out of the tap even if it is opened. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-196887 A [Patent Document 2] JP 2017-129328 A Summary of the Invention [Problem to be solved by the invention]

[0004] Regarding this issue, by connecting a water supply pipe connected to a dedicated faucet to the hot water storage tank and designing a hot water storage type hot water supply device so that hot water from the hot water storage tank comes out from the dedicated faucet by gravity, etc., it becomes possible to supply hot water from the hot water storage tank even when the water supply is stopped. In this case, even if hot water from the hot water storage tank is discharged from the dedicated faucet when the water supply is stopped, water from the water pipe is not poured into the hot water storage tank, and outside air taken in through the negative pressure operated valve flows into the hot water storage tank.

[0005] Meanwhile, a water volume sensor (flow rate sensor) that measures the flow rate of hot and cold water sent to the faucet is provided on the hot and cold water outlet side of the mixing valve, as described in Patent Document 2. The measurement value of the water volume sensor is used, for example, for control so that hot and cold water at a set hot water supply temperature is supplied to the faucet. Here, after the water supply infrastructure is restored, if air remains in the hot water tank and the faucet is opened, the air in the hot water tank will leave the tank, pass through the water level sensor, and be released to the outside from the faucet.

[0006] The impeller-type water sensor used in conventional storage-type hot water heaters is not designed to allow air to pass through it, and depending on the flow rate of air passing through the water sensor, it can spin freely and be damaged. The present invention has been made in consideration of such circumstances, and aims to provide a storage type hot water supply device that can prevent damage to an impeller-type water volume sensor even if air accumulates in the hot water storage tank when the water supply is stopped, and then the water faucet is opened when normal conditions are restored. [Means for solving the problem]

[0007] A storage type hot water supply device according to the present invention that meets the above-mentioned objective supplies hot water in a hot water storage tank to a first faucet during normal times when water from a water pipe is supplied to the hot water storage tank, and includes a hot water supply pipe that sends hot water from the hot water storage tank to the first faucet, a mixing valve C that is provided in the hot water supply pipe and mixes the hot water from the hot water storage tank with water from the water pipe, an impeller-type water volume sensor D downstream of the mixing valve C of the hot water supply pipe that measures the flow rate of hot water flowing through the hot water supply pipe, and a second faucet that dispenses hot water from the hot water storage tank during water supply stoppage when water from the water pipe is not supplied to the lower part of the hot water storage tank. the hot water storage tank includes an air acquisition means for taking in outside air that flows into the hot water storage tank as hot water is discharged from the second faucet; and a control means for adjusting the opening of the hot water inlet C1 of the hot water storage tank in the mixing valve C and the opening of the water inlet C2 of the water pipe, wherein when the control means detects the possibility of air flowing into the hot water storage tank as hot water is discharged from the second faucet, the control means returns to the normal state from the time the water supply is stopped, the first faucet is opened, and the opening of the inlet C2 of the mixing valve C is controlled to be equal to or greater than a predetermined opening J. Effect of the Invention

[0008] In the storage type hot water supply device of the present invention, when the control means detects the possibility of air flowing into the hot water storage tank due to the discharge of hot water from the storage tank from the second faucet, the control means returns to normal operation from when the water supply is stopped, opens the first faucet, and controls the mixing valve C to set the opening degree of the water inlet C2 of the water pipe of the mixing valve C to a predetermined opening degree J or more.Therefore, when air that has accumulated in the hot water storage tank when the water supply is stopped flows out of the first faucet under normal conditions, the water in the water pipe always flows through the impeller-type water volume sensor, preventing the water volume sensor from spinning freely due to air and suppressing damage to the water volume sensor. [Brief description of the drawings]

[0009] [Figure 1] 1 is a circuit diagram of a storage type hot water supply device according to one embodiment of the present invention. [Diagram 2] 1 is an explanatory diagram showing how hot water in a hot water storage tank is supplied to a first water faucet. [Diagram 3]FIG. 2 is a block diagram showing connections of a control means. [Figure 4] FIG. 2 is an explanatory diagram showing how the bathtub is filled with water. [Diagram 5] 13 is an explanatory diagram of how hot and cold water in the hot water storage tank is supplied to a second faucet. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Next, with reference to the attached drawings, an embodiment of the present invention will be described for understanding the present invention. As shown in Figure 1, the storage type hot water supply device 10 of the first embodiment of the present invention is a device that supplies hot water in the hot water storage tank 12 to an open first faucet 13 during normal operation when water from a water pipe 11 is supplied to the hot water storage tank 12.

[0011] 1, a plurality of (six in this embodiment) temperature sensors 14, 14a, 14b, 14c, 14d, and 14e are attached to the hot water storage tank 12. The temperature sensors 14, 14a, 14b, 14c, 14d, and 14e are arranged in the highest position, with the temperature sensor 14 provided at the top of the hot water storage tank 12 being arranged in the highest position, followed by the temperature sensors 14, 14a, 14b, 14c, 14d, and 14e in descending order. To the lower part of the hot water storage tank 12, one end of a water pipe 11 is connected, on which a pressure reducing valve 15, a temperature sensor 16, and check valves 17 and 18 are provided.

[0012] A first water faucet 13 provided in a kitchen, a washroom, etc. is connected to the downstream end of a hot water supply pipe 20 whose upstream end is connected to the top of the hot water storage tank 12. A check valve 21, a mixing valve C, an impeller-type water volume sensor D, and a temperature sensor 23 are provided on the hot water supply pipe 20 from the upstream end toward the downstream end. The mixing valve C is equipped with an inlet C1 (hot water inlet C1 of the hot water storage tank 12) through which hot water flows in from the top of the hot water storage tank 12, and an inlet C2 (water inlet C2 of the water pipe 11) to which another end of the water pipe 11 is connected and through which water from the water pipe 11 flows in, and mixes the hot water from the hot water storage tank 12 with the water from the water pipe 11.

[0013] The water volume sensor D is located downstream of the mixing valve C of the hot water supply pipe 20 and measures the flow rate of hot water flowing through the hot water supply pipe 20. When the first water faucet 13 is opened, the water pressure normally generated in the water pipe 11 causes the hot water in the upper part of the hot water storage tank 12 to be sent to the first water faucet 13 by the hot water supply pipe 20 via the mixing valve C and the water volume sensor D, as shown in Figure 2. Therefore, the hot water supply pipe 20 sends the hot water and cold water in the hot water storage tank 12 to the first water faucet 13.

[0014] As shown in Fig. 3, the mixing valve C and the water volume sensor D are connected to a control means 25 constituted by an IC chip or the like, together with the temperature sensors 14, 14a, 14b, 14c, 14d, 14e, 16, and 23. The control means 25 is connected to an operation terminal 26, through which various input operations, including the setting of the hot water supply temperature to the first water faucet 13, are performed. The control means 25 detects the measured values ​​of the temperature sensors 14, 16, and 23 and the water volume sensor D, and based on these measured values, adjusts the opening degree of the inlet C1 and the opening degree of the inlet C2 of the mixing valve C to control the mixing valve C so that hot water at the hot water supply temperature set by the operation terminal 26 is sent to the first water faucet 13. Here, the inlets C1 and C2 of the mixing valve C are linked so that when the opening degree of one of them increases, the opening degree of the other decreases, and the sum of the opening degrees of the inlets C1 and C2 is always 100%.

[0015] In addition, as shown in Figure 1, the hot water supply pipe 20 is connected to the upstream end of a hot water filling pipe 27 that sends hot water from the hot water storage tank 12 to the bathtub B, and the upstream end of a heat exchange circulation circuit 28 that heats the hot water in the bathtub B. The water filling pipe 27 is provided with a check valve 29, a mixing valve G, an impeller-type water volume sensor H, a solenoid valve 32, a check valve 33 and a temperature sensor 34, in that order, from its upstream end to its downstream end connected to the bathtub B.

[0016] The mixing valve G has an inlet G1 (hot water inlet G1 of the hot water storage tank 12) through which hot water flows in from the top of the hot water storage tank 12, and an inlet G2 (water inlet G2 of the water pipe 11) to which another end of the water pipe 11 is connected and through which water from the water pipe 11 flows in, and mixes the hot water from the hot water storage tank 12 with the water from the water pipe 11. The mixing valve G, the water volume sensor H, the solenoid valve 32, and the temperature sensor 34 are connected to the control means 25, as shown in Fig. 3. The water volume sensor H measures the flow rate of hot and cold water flowing through the filling pipe 27 downstream of the mixing valve G of the filling pipe 27.

[0017] When the operation to fill bathtub B is performed using operation terminal 26, solenoid valve 32 is opened by control means 25, and the water pressure in water pipe 11 causes the hot water in the upper part of hot water storage tank 12 and the water in water pipe 11 to be sent to mixing valve G, as shown in Fig. 4, mixed, and supplied to bathtub B. Based on the detection values ​​of temperature sensors 14, 16, 34 and water volume sensor H, control means 25 adjusts the opening degree of inlet G1 and the opening degree of inlet G2 of mixing valve G to control the temperature of the hot water supplied to bathtub B to the temperature set by operation terminal 26. Similar to inlets C1 and C2 of mixing valve C, inlets G1 and G2 of mixing source G are linked so that when the opening degree of one increases, the opening degree of the other decreases, and the sum of the opening degrees of inlets G1 and G2 is always 100%.

[0018] As shown in Fig. 1, the heat exchange circulation circuit 28 has a check valve 36 and a pump 37, and its downstream end is connected to the hot water storage tank 12. A water level sensor 38, a water flow switch 39, a temperature sensor 40, and a pump 41 are provided in the bathtub B, and the upstream end of a bath circulation circuit 42 is connected to the bathtub B, whose downstream end is connected to the hot water filling pipe 27. A heat exchanger 43 is attached to the heat exchange circulation circuit 28 and the bath circulation circuit 42, and the pumps 37, 41, the water level sensor 38, the water flow switch 39, and the temperature sensor 40 are connected to the control means 25, as shown in Fig. 3.

[0019] When the reheating operation is performed on the operation terminal 26, the control means 25 operates the pumps 37, 41 to return the hot water in the upper part of the hot water storage tank 12 to the hot water storage tank 12 through part of the hot water supply pipe 20 and the heat exchange circulation circuit 28, and to return the hot water in the bathtub B to the bathtub B through the bath circulation circuit 42 and part of the water filling pipe 27. As a result, heat is exchanged between the hot water flowing through the heat exchange circulation circuit 28 and the hot water flowing through the bath circulation circuit 42 by the heat exchanger 43, the hot water flowing through the bath circulation circuit 42 is heated, and the temperature of the hot water in the bathtub B rises.

[0020] Under normal conditions when water pressure is generated in water pipe 11, when first water faucet 13 is opened and hot water comes out, or when bathtub B is filled with water, the same amount of water as that sent out from the top of hot water storage tank 12 flows from water pipe 11 into the bottom of hot water storage tank 12. Therefore, under normal conditions, hot water storage tank 12 is filled with hot water.

[0021] In contrast, when the infrastructure for supplying tap water stops functioning, the water pressure in water pipe 11 drops and water from water pipe 11 is no longer supplied to the lower part of hot water storage tank 12. When the water supply is stopped and water from water pipe 11 is not supplied to the lower part of hot water storage tank 12, even if first water faucet 13 or solenoid valve 32 is opened, hot water from hot water storage tank 12 does not flow from the upper part of hot water storage tank 12 to hot water supply pipe 20, and neither hot water from hot water storage tank 12 nor water from water pipe 11 is sent to first water faucet 13 or bathtub B.

[0022] 1, the upstream end of a boiling circuit 44 is connected to the lower part of the hot water storage tank 12. The downstream end of the boiling circuit 44 is connected to the upper and lower parts of the hot water storage tank 12. As shown in FIGS. 1 and 3, the boiling circuit 44 has a pump 45, a heating means 46, and a switching means 47, each of which is connected to the control means 25. When the pump 45 is operated by the control means 25, hot water obtained from the lower part of the hot water storage tank 12 is returned to the upper or lower part of the hot water storage tank 12 via the pump 45, the heating means 46, and the switching means 47.

[0023] The heating means 46 is operated by the control means 25 to heat the hot water circulating through the boiling circuit 44. The boiling circuit 44 branches into two downstream of the switching means 47, one connected to the top of the hot water storage tank 12 and the other connected to the bottom of the hot water storage tank 12. The switching means 47 receives a command signal from the control means 25 and switches the destination of the hot water that has passed through the heating means 46 from one of the top and bottom of the hot water storage tank 12 to the other.

[0024] When the control means 25 detects that the amount of hot water (amount of boiling water) in the hot water storage tank 12 has decreased based on the measured temperatures of the temperature sensors 14, 14a, 14b, 14c, 14d, and 14e, it operates the pump 45 and the heating means 46 to circulate the hot water in the lower part of the hot water storage tank 12 to the boiling circuit 44 and boil the hot water storage tank 12. When the measured temperature of a temperature sensor (not shown) provided in the heating means 46 that measures the temperature of the hot water passing through the heating means 46 is below a predetermined value, the control means 25 changes the destination of the hot water sent by the switching means 47 to the lower part of the hot water storage tank 12, thereby preventing low-temperature hot water from flowing into the upper part of the hot water storage tank 12.

[0025] Upon detecting that the temperature of the hot water passing through the heating means 46 has reached or exceeded a predetermined value, the control means 25 switches the destination of the hot water from the switching means 47 to the upper part of the hot water storage tank 12, so that the hot water heated by the heating means 46 is supplied to the upper part of the hot water storage tank 12. As a result, hot water at a high temperature (e.g., 80°C) is stored from the upper part in the hot water storage tank 12. In this embodiment, a heat pump unit is used for the heating means 46, and a three-way valve is used for the switching means 47.

[0026] In addition, the upstream end of the water supply pipe 49 is connected to the region between the pump 45 and the heating means 46 of the boiling circuit 44, and the second water faucet 48 is connected to the downstream end of the water supply pipe 49. When the water supply is stopped, the control means 25 operates the pump 45 by a predetermined input operation being performed on the operation terminal 26, and as shown in FIG. 5, the hot water supply device 10 is placed in a state in which the hot water in the hot water storage tank 12 flows out of the second water faucet 48 via the water supply pipe 49 (hereinafter, this state is referred to as an "emergency water supply state"). Thus, when the water supply is stopped, the hot water supply device 10 is placed in the emergency water supply state, the pump 45 is operated to send the hot water in the hot water storage tank 12 to the second water faucet 48, and the second water faucet 48 is opened to dispense the hot water in the hot water storage tank 12.

[0027] The control means 25 can set the switching means 47 to a state in which hot water in the boiling circuit 44 is not intentionally sent to either the upper or lower part of the hot water storage tank 12, whereby the boiling circuit 44 is in a state in which the return of hot water to the hot water storage tank 12 is stopped (hereinafter, this state is referred to as the water stop state). Depending on the design of the switching means 47, in the water stop state, a small amount of hot water (for example, one-tenth the amount when the sending side of the switching means 47 is fully open) is sent to the upper or lower part of the hot water storage tank 12. In this embodiment, when the storage type hot water supply device 10 is put into an emergency water supply state, the boiling circuit 44 is brought into a water stopping state and the heating means 46 is brought into a non-operating state.

[0028] A connection pipe 51 equipped with a negative pressure operated relief valve (one example of an air acquisition means) 50 is connected to the hot water supply pipe 20. The negative pressure operated relief valve 50 has a function of discharging the hot water in the hot water storage tank 12 that expands as the hot water storage tank 12 is heated to the outside via the hot water supply pipe 20 and the connection pipe 51, and a function of taking in air from the outside when the hot water storage tank 12 becomes negative pressure, and causing the air to flow into the hot water storage tank 12 via the connection pipe 51 and the hot water supply pipe 20.

[0029] As hot water flows out of the hot water storage tank 12 from the second faucet 48, negative pressure is created inside the hot water storage tank 12, and outside air is taken into the negative pressure operated relief valve 50 and flows into the top of the hot water storage tank 12 via the connecting pipe 51 and the hot water supply pipe 20, causing air to accumulate inside the hot water storage tank 12 from the top. Therefore, the negative pressure operated relief valve 50 takes in the outside air that flows into the hot water storage tank 12 as hot water flows out of the hot water storage tank 12 from the second faucet 48.

[0030] By a specified input operation on operation terminal 26, storage type hot water supply apparatus 10 goes into an emergency restriction state in which heating of storage tank 12 (operation of heating means 46), filling bathtub B with hot water, and reheating hot water in bathtub B are prohibited. In this embodiment, an input operation on operation terminal 26 is used to input the storage type hot water supply apparatus 10 into the emergency restriction state and the input operation to put storage type hot water supply apparatus 10 into the emergency water supply state. In other words, by the input operation on operation terminal 26, control means 25 operates pump 45 (hereinafter, this input operation on operation terminal 26 is referred to as pump start input).

[0031] When the button is pressed continuously (long pressed) for a certain period of time (e.g., 5 seconds), control means 25 puts storage type hot water supply apparatus 10 into the emergency restriction state, and when the button is pressed and held again, control means 25 releases the emergency restriction state of storage type hot water supply apparatus 10 (and the emergency water supply state if storage type hot water supply apparatus 10 was in the emergency water supply state). When the button is pressed normally (not long pressed), storage type hot water supply apparatus 10 in the emergency restriction state goes into the emergency water supply state while maintaining the emergency restriction state, and when the button is pressed normally again, only the emergency water supply state is released.

[0032] When the water supply is stopped, hot water is released from second faucet 48 in hot water storage tank 12, and the air that has accumulated in hot water storage tank 12 remains in hot water storage tank 12 even when normal conditions are restored and water pressure is applied to water pipe 11 and the emergency restriction state of hot water storage type hot water supply device 10 is released. This is because negative pressure operated relief valve 50 is designed not to release the air in hot water storage tank 12 to the outside.

[0033] When air is accumulated at the top of hot water storage tank 12 and first faucet 13 is opened (or bathtub B is filled with water), air rather than hot water comes out of hot water storage tank 12 and passes through water volume sensor D (or water volume sensor H). Because water volume sensors D and H are impeller type, if all or most of the fluid flowing through water volume sensors D and H (for example, 95% or more of the total flow rate) is air, the impeller portion of water volume sensors D and H will spin freely and may be damaged.

[0034] Therefore, the control means 25 detects the possibility of air flowing into the hot water storage tank 12 due to the discharge of hot water from the hot water storage tank 12 from the second water faucet 48 when the water supply is stopped, and controls the mixing valve C to set the opening of the inlet C2 of the mixing valve C to a predetermined opening J (for example, an opening in the range of 5% to 20%) or more when normal operation is restored and the first water faucet 13 is opened. Hereinafter, this control of the mixing valve C will be referred to as sensor protection control by the mixing valve C.

[0035] Specifically, when the sensor protection control by the mixing valve C is in operation, even if it is necessary to set the opening degree of the inlet C2 of the mixing valve C to a value smaller than the opening degree J in order to send hot water at the hot water supply temperature set by the operation terminal 26 to the first faucet 13, the control means 25 sets the opening degree of the inlet C2 to the opening degree J. On the other hand, when it is possible to send hot water at the hot water supply temperature set by the operation terminal 26 to the first faucet 13 by setting the opening degree of the inlet C2 of the mixing valve C to the opening degree R that is equal to or greater than the opening degree J, the control means 25 sets the opening degree of the inlet C2 to the opening degree R. This ensures that an amount of water sufficient to prevent the water sensor D from running idly is always sent from the water pipe 11 to the water sensor D via the mixing valve C while the sensor protection control by the mixing valve C is in operation.

[0036] The same is true when bathtub B is filled with water using operation terminal 26, and control means 25 detects the possibility of air flowing into hot water storage tank 12 due to the discharge of hot water from second faucet 48 when the water supply is stopped, and controls mixing valve G to set the opening of inlet G2 of mixing valve G to a predetermined opening K or more (for example, an opening in the range of 5% to 20%) when returning to normal operation and sending hot water from hot water storage tank 12 to bathtub B. Hereinafter, this control of mixing valve G will be referred to as sensor protection control by mixing valve G.

[0037] Specifically, when sensor protection control by mixing valve G is in operation, even if it is necessary to set the opening of inlet G2 of mixing valve G to a value smaller than opening K in order to send hot water at the filling temperature set by operation terminal 26 to bathtub B, control means 25 sets the opening of inlet G2 to opening K. On the other hand, if it is possible to send hot water at the filling temperature set by operation terminal 26 to bathtub B by setting the opening of inlet G2 of mixing valve G to opening S that is equal to or greater than opening K, control means 25 sets the opening of inlet G2 to opening S. This ensures that an amount of water sufficient to prevent the water sensor H from running idly is always sent from the water pipe 11 to the water sensor H via the mixing valve G while sensor protection control by mixing valve G is in operation.

[0038] In this embodiment, the control means 25 detects a pump start input on the operation terminal 26, detects the possibility of air flowing into the hot water storage tank 12 as hot water from the hot water storage tank 12 flows out from the second water faucet 48, and when normal operation is resumed, performs sensor protection control by the mixing valve C and sensor protection control by the mixing valve G. Even if a pump start input is received on the operation terminal 26, unless the second water faucet 48 is opened, the hot water from the hot water storage tank 12 will not flow out from the second water faucet 48 and air will not flow into the hot water storage tank 12. Therefore, in this embodiment, even if air is not flowing into the hot water storage tank 12, the sensor protection control by the mixing valve C and the sensor protection control by the mixing valve G may be performed.

[0039] In addition, when either or both of the sensor protection control by mixing valve C and the sensor protection control by mixing valve G are operating, the control means 25 cancels the sensor protection control by mixing valve C and the sensor protection control by mixing valve G when any of the conditions 1, 2, or 3 described below is satisfied.

[0040] <Condition 1> When the opening degree of the inlet C1 of the mixing valve C is set to a preset opening degree U1 or more, hot water from the hot water storage tank 12 is allowed to flow into the hot water supply pipe 20, and the temperature measured by the temperature sensor 23 is within ±α°C of the hot water supply temperature set on the operation terminal 26, and the measurement value by the water volume sensor D is detected to be V1 or more continuously for a certain period of time (e.g., 30 seconds).

[0041] <Condition 2> When the opening degree of the inlet G1 of the mixing valve G is set to a preset opening degree U2 or more, hot water from the hot water storage tank 12 is allowed to flow through the filling pipe 27, and the temperature measured by the temperature sensor 34 is within ±α°C of the filling temperature set on the operation terminal 26, and the measurement value by the water volume sensor H is detected to be V2 or more continuously for a certain period of time (e.g., 30 seconds).

[0042] <Condition 3> When the sum of the integrated flow rate measured by water flow sensor D when the opening of inlet C1 of mixing valve C is set to a predetermined opening U3 or more, and the integrated flow rate measured by water flow sensor H when the opening of inlet G1 of mixing valve G is set to a predetermined opening U4 or more, becomes equal to or greater than the predetermined W.

[0043] In this embodiment, the opening degrees U1, U2, U3, and U4 are each in the range of 5% or more and 90% or less, α°C is in the range of 0.5°C or more and 2°C or less, V1 and V2 are each in the range of 3 L / min or more and 10 L / min or less, and W is in the range of 100 L or more and 300 L or less.

[0044] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and all changes in conditions that do not depart from the gist of the present invention are within the scope of application of the present invention. For example, the upstream end of the water supply pipe, the downstream end of which is connected to the second faucet, may be connected directly to the bottom of the hot water storage tank without being connected to the boiling circuit. When the upstream end of the water supply pipe is connected directly to the bottom of the hot water storage tank, the water supply pipe may be provided with a pump that sends hot water from the bottom of the hot water storage tank to the second faucet, or such a pump may not be provided and the hot water from the hot water storage tank may be allowed to come out of the second faucet by gravity. In addition, in a storage type hot water supply device that is not designed to fill a bathtub with hot water, a mixing valve is used to perform sensor protection control for a water volume sensor installed in a hot water supply pipe.

[0045] The control means does not need to detect the pump start input from the operation terminal and detect the possibility of air flowing into the hot water storage tank when hot water is discharged from the second faucet, and may, for example, detect the possibility of air flowing into the hot water storage tank when hot water is discharged from the second faucet by providing a water volume sensor in the water supply pipe and basing the detection on the measurement value of the water volume sensor, or by providing a pressure sensor that measures the pressure inside the hot water storage tank and basing the detection on the measurement value of the pressure sensor. However, in these cases, it is necessary to add a water volume sensor, pressure sensor, etc. [Explanation of symbols]

[0046] 10: storage type hot water supply device, 11: water pipe, 12: hot water storage tank, 13: first water faucet, 14, 14a, 14b, 14c, 14d, 14e: temperature sensor, 15: pressure reducing valve, 16: temperature sensor, 17, 18: check valve, 20: hot water supply pipe, 21: check valve, 23: temperature sensor, 25: control means, 26: operation terminal, 27: hot water filling pipe, 28: heat exchange circulation circuit, 29: check valve, 32: solenoid valve, 33: check valve, 34: temperature sensor, 36: check valve Stop valve, 37: pump, 38: water level sensor, 39: water flow switch, 40: temperature sensor, 41: pump, 42: bath circulation circuit, 43: heat exchanger, 44: boiling circuit, 45: pump, 46: heating means, 47: switching means, 48: second faucet, 49: water supply pipe, 50: relief valve with negative pressure actuated valve, 51: connecting pipe, B: bathtub, C: mixing valve, C1, C2: inlet, D: water volume sensor, G: mixing valve, G1, G2: inlet, H: water volume sensor

Claims

1. In a storage-type hot water supply device, when water from a water pipe is normally supplied to the hot water storage tank, hot water in the hot water storage tank is supplied to a first water faucet, a hot water supply pipe for supplying hot water from the hot water storage tank to the first water faucet; A mixing valve C provided in the hot water supply pipe for mixing hot water from the hot water storage tank with water from the water pipe; a water flow sensor D of an impeller type that is located downstream of the mixing valve C of the hot water supply pipe and measures the flow rate of hot water flowing through the hot water supply pipe; a second water faucet that supplies hot water from the hot water storage tank when the water supply is stopped and water from the water pipe is not supplied to the lower part of the hot water storage tank; an air acquisition means for taking in outside air that flows into the hot water storage tank as hot water is discharged from the second water faucet; a control means for adjusting the opening degree of the hot water inlet C1 of the hot water storage tank and the opening degree of the water inlet C2 of the water pipe in the mixing valve C; This storage-type hot water supply device is characterized in that, when the control means detects the possibility of air flowing into the hot water storage tank due to the discharge of hot water from the second faucet, the control means returns to normal operation from the time the water supply is stopped, the first faucet is opened, and the opening degree of the inlet C2 of the mixing valve C is controlled to a predetermined opening degree J or more.

2. 2. The hot water supply device of claim 1, further comprising a hot water filling pipe for sending hot water from the hot water storage tank to a bathtub, a mixing valve G provided on the hot water filling pipe for mixing the hot water from the hot water storage tank with water from the water pipe, and an impeller-type water volume sensor H downstream of the mixing valve G on the hot water filling pipe for measuring the flow rate of hot water flowing through the hot water filling pipe, wherein the control means also adjusts the opening degree of the hot water inlet G1 of the hot water storage tank and the opening degree of the water inlet G2 of the water pipe, and wherein when the control means detects the possibility of air flowing into the hot water storage tank due to the hot water discharge from the second faucet, when returning to the normal operation from the time the water supply is stopped and sending hot water from the hot water storage tank to the bathtub, the control means controls the opening degree of the inlet G2 of the mixing valve G to be equal to or greater than a predetermined opening degree K.

3. In the storage type hot water supply device described in claim 1 or 2, the storage type hot water supply device further comprises a pump that operates to send hot water from the hot water storage tank to the second faucet when the water supply is stopped, and an operation terminal that can input a pump start input to the control means to operate the pump, wherein the control means detects the pump start input at the operation terminal and detects the possibility of air flowing into the hot water storage tank when hot water from the hot water storage tank is discharged from the second faucet.

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