JP2012181002A - Hot water storing type hot water supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain reliable and rapid water discharge of all hot water storing tanks in a hot water storing type hot water supply device having a plurality of hot water storing tanks.SOLUTION: The hot water storing type hot water supply device includes: first and second hot water storing tanks 1 and 2 storing hot water; a heater 34 boiling hot water in the first and second hot water storing tanks 1 and 2; first and second water supply pipes 3 and 4 supplying water to respective lower parts of the first and second hot water storing tanks 1 and 2; first and second hot water supply pipes 5 and 6 supplying hot water from respective upper parts of the first and second hot water storing tanks 1 and 2; a hot water supply mixing valve 11 mixing and supplying hot water from the first and second hot water supply pipes 5 and 6 when the hot water is supplied; an atmospheric release valve 10 branch-connected from the first hot water supply pipe 5 or the second hot water supply pipe 6; and a water discharge plug 39 communicating with bottom parts of the first and second hot water storing tanks 1 and 2. When water is discharged, the hot water supply mixing valve 11 is controlled in such an opening degree that the first and second hot water supply pipes 5 and 6 communicate with each other.

Description

  The present invention relates to a hot water storage type hot water supply apparatus having a plurality of hot water storage tanks.

  Conventionally, in a hot water storage type hot water supply apparatus having a plurality of hot water storage tanks of this type, as shown in FIG. 4, a plurality of hot water storage tanks A and B for storing hot water and a hot water supply from the top of the hot water storage tank A are used. Hot water supply pipe 101, water supply pipe 102 for supplying water to the bottom of hot water storage tank B, communication pipe 103 connecting the top of hot water storage tank B and the bottom of hot water storage tank A, and bath water provided in the upper part of hot water storage tank A Bath heat exchanger 104 for heating the water, heat pump type heating means 105 for heating the hot water in the hot water storage tanks A and B, and hot water discharged from the bottom of the hot water storage tank B are introduced to the heat pump type heating means 105. A water pipe 106, a heating pipe 107 that leads hot water heated by the heat pump heating means 105 to the top of the hot water storage tank A, an air release valve 108 that is branched from the hot water supply pipe 101, and a hot water storage tank A drain plug 109 and a drain plug 110 respectively connected to the bottom of the hot water storage tank B and the bottom of the hot water storage tank B are provided in the heat pump heating means 105 during the boiling operation for boiling the hot water in the hot water storage tanks A and B. The circulating pump (not shown) is driven to heat the hot water discharged from the bottom of the hot water storage tank B, return from the top of the hot water storage tank A, and fill up to the bottom of the hot water storage tank B via the connecting pipe 103. When boiling and hot water is supplied, hot water in the upper part of the hot water storage tank A is pushed out through the connecting pipe 103 by water supplied from the bottom of the hot water storage tank B (Patent Document 1). ).

JP 2002-139251 A

  However, in this conventional apparatus, in order to drain hot water in the hot water storage tank A and the hot water storage tank B, both the tanks can be drained by opening the air release valve 108 and the drain valves 109 and 110. However, until the drainage of the hot water storage tank A is completed and one end of the connecting pipe 103 is exposed to the air, the hot water storage tank B cannot be drained, and drainage takes time.

  In order to solve the above-described problems, the present invention provides, in claim 1, a first hot water storage tank and a second hot water storage tank for storing hot water, heating means for boiling the hot water in the first hot water storage tank and the second hot water storage tank, The atmosphere open valve communicated with the upper part of the first hot water storage tank and the upper part of the second hot water storage tank, and the drain plug communicated with the bottom part of the first hot water storage tank and the bottom part of the second hot water storage tank.

  According to a second aspect of the present invention, the hot water is discharged from the first and second hot water supply pipes that supply water to the lower portions of the first hot water storage tank and the second hot water storage tank, and from the upper portions of the first hot water storage tank and the second hot water storage tank, respectively. From the first tapping pipe, the second tapping pipe, from the first tapping pipe, from the first tapping pipe, from the first tapping pipe, or from the second tapping pipe. The atmosphere open valve that is branched and connected is provided, and the drain hot water mixing valve is held at an opening degree where the first hot water discharge pipe and the second hot water discharge pipe communicate with each other during drainage.

  According to a third aspect of the present invention, the atmosphere release valve is provided as an atmosphere release valve with an overpressure relief valve mechanism branched from the first hot water discharge pipe, and the heating means raises the second hot water storage tank at the time of boiling. After that, the first hot water storage tank was boiled.

  According to a fourth aspect of the present invention, the hot water mixing valve closes between the first hot water pipe and the second hot water pipe at least during boiling of the second hot water storage tank.

  According to a fifth aspect of the present invention, a heating circuit for circulating hot water in the first hot water storage tank and the second hot water storage tank to the heating means and one of hot water in the first hot water storage tank and the second hot water storage tank are selectively used. Circulation switching means for switching the flow path of the heating circulation circuit to circulate to the heating means, and the heating circulation circuit has a flow path returning from the heating means to the first hot water storage tank and the second hot water storage tank. The first hot water pipe and the second hot water pipe are connected to the first hot water pipe and the second hot water pipe through the hot water mixing valve, the first hot water pipe and the second hot water pipe are shared as a part of the heating circulation circuit, and the circulation switching means is The hot water mixing valve is shared.

  In the sixth aspect of the present invention, the hot water mixing valve is configured such that the first hot water pipe and the second hot water pipe communicate with each other even at the maximum valve opening and the minimum valve opening.

  According to claim 1, it is possible to drain the first hot water storage tank and the second hot water storage tank at the same time with a single air release valve and drain plug, and it is possible to reliably drain the first hot water storage tank and the second hot water storage tank. At the same time, the time required for drainage can be greatly reduced.

  According to claim 2, for example, if an air release valve is provided on the first hot water discharge pipe side, the air sucked from the air release valve provided on the first hot water discharge pipe is discharged to the first hot water storage tank during drainage. The second hot water storage tank is supplied with air sucked by the air release valve via the hot water mixing valve and the second hot water discharge pipe, so that the first hot water storage tank and the second hot water storage tank can be drained simultaneously. Thus, the first hot water storage tank and the second hot water storage tank can be reliably drained, and the time required for draining can be greatly shortened.

  According to the third aspect, while the second hot water storage tank is being boiled, the hot water stored in the upper portion of the first hot water storage tank is discharged from the atmospheric release valve with an overpressure relief valve mechanism by an amount corresponding to the overpressure expansion. Wasted hot water can be suppressed.

  According to claim 4, while the second hot water storage tank is being boiled, only the hot water stored in the upper portion of the first hot water storage tank is discharged from the atmospheric release valve with an overpressure relief valve mechanism by an amount corresponding to the overpressure expansion. Wasted boiling water can be further suppressed.

  According to the fifth aspect, the number of pipes and the number of valve bodies can be reduced, and a low-cost and simple structure can be achieved.

  According to the sixth aspect of the present invention, the first hot water discharge pipe and the second hot water discharge pipe always communicate with each other, and the first hot water storage tank and the second hot water storage tank always communicate with the air release valve. The drainage of the first hot water storage tank and the second hot water storage tank can be reliably performed.

1 is a schematic configuration diagram of a hot water storage bath water heater according to an embodiment of the present invention. The flowchart which shows the action | operation at the time of boiling of the same embodiment The flowchart which shows the action | operation at the time of the hot water supply of the same embodiment Schematic configuration diagram of a conventional hot water storage bath water heater

Next, a hot water storage type hot water supply apparatus according to an embodiment of the present invention will be described with reference to the drawings.
1 is a first hot water storage tank for storing hot water, 2 is a second hot water storage tank provided in parallel to the first hot water storage tank for storing hot water, 3 is a first water supply pipe for supplying water to the lower part of the first hot water storage tank 1, and 4 is a first 2 A second water supply pipe for supplying water to the lower part of the hot water storage tank 2, 5 is a first hot water discharge pipe for discharging hot water from the upper part of the first hot water storage tank 1, 6 is a second hot water discharge pipe for discharging hot water from the upper part of the second hot water storage tank 2, and 7 is a pressure reducing valve 8. And a water supply check valve 9, and a water supply main pipe that branches into the first water supply pipe 3 and the second water supply pipe 4 downstream thereof.

  Reference numeral 10 is provided to be branched from the first hot water discharge pipe 5 and has an overpressure relief valve mechanism for automatically releasing the overpressure expansion of the first hot water storage tank 1 and the second hot water storage tank 2 and can be manually opened. It is an overpressure relief valve as an atmospheric release valve.

  11 is a hot water mixing valve that mixes hot water from the first hot water pipe 5 and hot water from the second hot water pipe 6 and discharges hot water, 12 is a mixed hot water pipe that supplies hot water mixed by the hot water mixing valve 11, and 13 is a mixture. A hot water temperature sensor 14 is provided in the hot water pipe 12 and detects the temperature of the hot water mixed by the hot water mixing valve 11, and 14 is a first water supply bypass branched from between the pressure reducing valve 8 and the water supply check valve 9 of the water supply main pipe 7. A hot water mixing valve 15 for supplying hot water by mixing hot water from the mixed hot water supply pipe 12 and water from the first water supply bypass pipe 14, 16 is a hot water supply pipe for supplying hot water mixed by the hot water mixing valve 15, 17 Is a hot water temperature sensor that detects the temperature of hot water mixed in the hot water mixing valve 15 provided in the hot water supply pipe 16, 18 is a hot water flow rate counter that counts the amount of hot water supplied through the hot water pipe 16, and 19 is a hot water pipe. Hot water check that prevents backflow of hot water at 16 It is.

  20 is a bath hot water pipe branched from the mixed hot water pipe 12, 21 is a second water supply bypass pipe branched from between the pressure reducing valve 8 and the water supply check valve 9 of the water supply main pipe 7, and 22 is from the bath hot water pipe 20. A bath mixing valve for mixing hot water and water from the second water supply bypass pipe 21 and filling the bathtub 23 with hot water, and 24 a hot water filling pipe for supplying hot water mixed with the bath mixing valve 22 to the bathtub 23, 25 is a bath flow counter that counts the amount of hot water that is hot watered via the hot water tube 24, 26 is a hot water valve that opens and closes the hot water tube 24 to control the start and stop of the hot water, and 27 is a hot water tube. This is a bath check valve that prevents the backflow of hot water at 24.

  28 is a bath heat exchanger for circulatingly heating the bath water in the bathtub 23, 29 is composed of a bath outlet pipe 30 and a bath return pipe 31 that connect the bathtub 23 and the bath heat exchanger 28 so that the bath water can circulate. A bath circulation circuit 32 is provided in the bath return pipe 31 and is a bath circulation pump for pumping bath water to the bath heat exchanger 28, and 33 is a bath water circulated provided near the connection point between the bath return pipe 31 and the hot water pipe 24. This is a bath temperature sensor that detects the temperature of the water and the temperature of hot water charged from the hot water pipe 24.

  Reference numeral 34 denotes a heat pump type heating means for heating the hot water in the first hot water storage tank 1 and the second hot water storage tank 2, and includes a compressor, a refrigerant water heat exchanger 34a, an expansion valve, and an air heat exchanger (not shown) inside. A heat pump cycle, a blower that blows outside air to the air heat exchanger, and a heating circulation pump 34b that circulates hot water in the first hot water storage tank 1 and the second hot water storage tank 2 to the refrigerant water heat exchanger. is there.

  35 is a first water intake pipe provided at the bottom of the first hot water storage tank 1 and sends hot water from the bottom of the first hot water storage tank 1 to the heating means 34, and 36 is provided at the bottom of the second hot water storage tank 2 and is located at the bottom of the second hot water storage tank 2. A second water intake pipe 37 for sending hot water to the heating means 34, 37 is a water inlet connected to the water side inlet of the refrigerant water heat exchanger 34 a of the heating means 34, which is formed by joining the first water intake pipe 35 and the second water intake pipe 36. The main pipe 38 is connected to the water side outlet of the refrigerant water heat exchanger 34a of the heating means 34, and is a boiling pipe for returning the hot water boiled by the heating means 34 to the first hot water storage tank 1 and the second hot water storage tank 2. Reference numeral 39 denotes a drain plug that is branched from the incoming water main pipe 37 and is configured to be manually opened.

  The boiling pipe 38 is connected to the mixed hot water pipe 12 on the downstream side of the hot water mixing valve 11, and hot water boiled by the heating means 34 via the first hot water pipe 5 and the second hot water pipe 6 is used in the first hot water storage tank 1. The first water intake pipe 35, the second water intake pipe 36, the water input main pipe 37, the boiling pipe 38, the mixed hot water pipe 12, the first hot water pipe 5, the second water storage tank 2 are returned to the upper part. A heating circulation circuit 40 is constituted by the hot water discharge pipe 6. Here, the hot water mixing valve 11 is operable as a circulation switching means for switching whether the hot water boiled by the heating means 34 is returned to the upper part of the first hot water storage tank 1 or the upper part of the second hot water storage tank 2.

  41 is a heating bypass pipe connected to a water supply main pipe 7 branched in the middle of the heating pipe 38 and connected to the lower portions of the first hot water storage tank 1 and the second hot water storage tank 2, and 42 is a heating pipe 38 and a heating bypass pipe. Whether the hot water circulated through the heating means 34 provided at a branch point with 41 is returned to the lower part of the first hot water tank 1 and the second hot water tank 2 or returned to the upper part of the first hot water tank 1 and the second hot water tank 2 It is a boiling-up switching valve for switching between.

  A plurality of (four in this case) 43 are provided on the upper and lower sides of the first hot water storage tank 1, and a first hot water temperature sensor 44 detects the temperature of the hot water in the first hot water storage tank 1. 44 is the upper and lower sides of the second hot water storage tank 2. A plurality of (three in this case) are provided, and a second hot water storage temperature sensor for detecting the temperature of the hot water in the second hot water storage tank 2 includes a first hot water storage temperature sensor 43a, a first hot water storage temperature sensor 43b, The hot water storage temperature sensor 43c, the first hot water storage temperature sensor 43d, the second hot water storage temperature sensor 44a, the second hot water storage temperature sensor 44b, and the second hot water storage temperature sensor 44c are called the uppermost first hot water storage temperature sensor 43a and the second hot water storage temperature sensor. The temperature of the hot water discharged from the first hot water storage tank 1 and the second hot water storage tank 2 is detected by 44a, and the first hot water storage tank 1 is detected by the first hot water storage temperature sensor 43d and the second hot water storage temperature sensor 44c. And a temperature for determining whether the second hot water storage tank 2 has been fully filled up, and the temperature of the water supplied from the main water supply pipe 7 by the second hot water storage temperature sensor 44c at the bottom of the second hot water storage tank 2 is detected. To detect.

  Reference numeral 45 denotes a remote controller for setting and operating a display unit 46 for displaying various information related to the hot water supply device (hot water supply set temperature, bath set temperature, remaining hot water amount, operating state of the hot water supply device, etc.), and hot water set temperature and bath set temperature. Temperature setting switch 47, hot water filling switch 48 for instructing the bathtub 23 to fill with a certain amount of water, and waste water for instructing to perform a preparatory operation for draining the first hot water storage tank 1 and the second hot water storage tank 2. Various switches such as a switch 49 are provided.

  50, the detection values of the hot water temperature sensor 13, the hot water temperature sensor 17, the hot water flow rate counter 18, the bath flow rate counter 25, the bath temperature sensor 33, the first hot water temperature sensors 43a to 43d, and the second hot water temperature sensors 44a to 44c are input. It controls the operation of the hot water mixing valve 11, hot water supply mixing valve 15, bath mixing valve 22, hot water filling valve 26, bath circulation pump 32, and boiling switching valve 42, and is connected to the remote controller 45 and the heating means 34 so as to be communicable. Tank control means. The tank control means 50 stores a program for controlling the operation of the hot water supply device in advance, and has a calculation, comparison, storage function, and clock function.

  51 receives the input of the temperature etc. of the required place in the heating means 34, controls the operation | movement of a compressor, an expansion valve, an air blower, and the heating circulation pump 34b, and is connected to the tank control means 50 so that communication is possible. A program for controlling the operation of the heating means 34 is stored in advance, and has a calculation, comparison, and storage function.

<Boiling operation>
Next, the action | operation at the time of a boiling operation is demonstrated based on the flowchart of FIG.
When the tank control means 50 recognizes that it has become an inexpensive midnight time zone of the unit price of electricity bill (Yes in step S1), the tank control means 50 determines the amount of hot water supplied so far and the first hot water storage temperature sensors 43a to 43d. The amount of remaining hot water in the first hot water storage tank 1 and the second hot water storage tank 2 detected by the second hot water storage temperature sensors 44a to 44c and the water supply temperature detected by the second hot water storage temperature sensor 44c at the bottom of the second hot water storage tank 2 Based on the following formula, the temperature in the midnight time zone is calculated, and the calculated temperature is rounded up to a temperature of 5 ° C. to determine the boiling target temperature.

Boiling target temperature = {(outgoing hot water amount−remaining hot water amount) / (tank capacity−remaining hot water amount)} + feed water temperature Here, the tank capacity is based on the total capacity of the first hot water storage tank 1 and the second hot water storage tank 2 in advance. A predetermined value (here, a value obtained by subtracting the minimum hot water storage amount to be secured from the total capacity until the start of the midnight time zone) is used, and the remaining hot water amounts are the first hot water storage temperature sensors 43a to 43d and the second hot water storage temperature sensor. In 44a-c, the amount of remaining hot water is detected from the distribution state of hot water at a predetermined temperature (for example, 50 ° C.) or higher, which is difficult to re-boiling with the heat pump type heating means 34.

  Then, the tank control means 50 calculates a boiling amount (tank total capacity-remaining hot water amount) (step S2), and from this boiling amount, the boiling target temperature, and the rated heating capacity of the heat pump type heating means 34, it is midnight. A boiling start time at which the amount of heat necessary for the next day rises before the end time of the time zone is calculated by peak shift calculation (step S3).

  When the current time reaches the boiling start time (Yes in step S4), the tank control means 50 switches the boiling switching valve 42 to the boiling bypass pipe 41 side (step S5), and the heat pump type heating means 34 The heating control means 51 is instructed to start the boiling operation at the calculated boiling target temperature, and the heating control means 51 that receives the instruction detects the refrigerant with a boiling temperature sensor (not shown). The compressor, the expansion valve, the blower, and the heating circulation pump 34b are driven and controlled so that the temperature of the hot water flowing out from the water heat exchanger 34a becomes the boiling target temperature (step S6).

  At this time, the low-temperature hot water before the heat pump type heating means 34 reaches the predetermined start-up temperature near the boiling target temperature is supplied from the heating pipe 38 through the heating bypass pipe 41 to the first hot water storage tank 1. And it returns to the bottom part of the 2nd hot water storage tank 2, and mixes with the hot water of the upper part of the 1st hot water storage tank 1 and the 2nd hot water storage tank 2 is avoided.

  When the heating control means 51 detects that the boiling temperature sensor has reached a predetermined start-up temperature (here, 50 ° C.) or higher (step S7), the heating control means 51 transmits that fact to the tank control means 50, and this signal , The tank control means 50 switches the opening degree of the hot water mixing valve 11 to 100% on the second hot water outlet pipe 6 side (step S8), and then switches the boiling switching valve 42 to the side of the hot water pipe 38 ( In step S9), hot water boiled by the heat pump type heating means 34 is stored from the upper part of the second hot water storage tank 2.

  At this time, hot water boiled up by the heat pump type heating means 34 is stored in the second hot water storage tank 2, and at the same time, the hot water expands due to heating to an overpressure state, and the valve opening pressure of the relief valve 10 is increased. Exceeds the above, the relief valve 10 is opened and the remaining hot water of the previous day stored in the upper part of the first hot water storage tank 1 is expanded and discharged, and the hot water immediately after boiling is not discharged, but the second hot water storage tank 2 is discharged. The hot water storage efficiency can be increased.

  When the boiling of the second hot water storage tank 2 proceeds and the second hot water temperature sensor 44c at the bottom of the second hot water storage tank 2 detects a predetermined full tank temperature (55 ° C. here) (Yes in step S10), tank control is performed. The means 50 switches the opening of the hot water mixing valve 11 to 100% on the first hot water pipe 5 side (step S11), and stores hot water boiled by the heat pump type heating means 34 from the upper part of the first hot water storage tank 1. I have to.

  When the boiling of the first hot water storage tank 1 proceeds and the first hot water temperature sensor 44d at the bottom of the first hot water storage tank 1 detects a predetermined full tank temperature (55 ° C. here) (Yes in step S12), tank control is performed. In preparation for the subsequent start of hot water supply, the means 50 switches the opening degree of the hot water mixing valve 11 to 100% on the second hot water discharge pipe 6 side (step S13), and instructs the heating control means 51 to end the boiling operation. Upon receiving the instruction, the heating control means 51 stops driving the compressor, the expansion valve, the blower, and the heating circulation pump 34b, and ends the boiling operation (step S14).

<Hot water supply operation>
Next, the operation during the hot water supply operation will be described based on the flowchart of FIG.
A hot water tap (not shown) provided at the tip of the hot water supply pipe 16 is opened, and city water flows from the second water supply pipe 4 into the bottom of the second hot water storage tank 2 and is second from the top of the second hot water storage tank 2. Hot water flows out through the hot water outlet pipe 6, flows through the hot water mixing valve 11 and the mixed hot water outlet pipe 12, is mixed with water from the first water supply bypass pipe 14 by the hot water supply mixing valve 15, and is supplied from the hot water supply pipe 16. .

  When the hot water supply flow counter 18 detects a flow rate equal to or higher than the minimum operation amount (Yes in step S21), the tank control means 50 checks the temperature of the hot water flowing out from the hot water mixing valve 11 detected by the hot water temperature sensor 13, It is determined whether or not the temperature is equal to or higher than a predetermined temperature (for example, a hot water supply set temperature + a constant temperature) based on the hot water supply set temperature (step S22).

  At the time when the total amount of hot water supply from the end of the boiling operation has not increased so much, the hot water mixing valve 11 is set to 100% on the second outlet pipe 6 side in step S13 of FIG. Since the temperature detected by the tapping temperature sensor 13 is also high and it is determined Yes in step S22, the hot water in the second hot water storage tank 2 is selectively discharged in preference to the hot water in the first hot water storage tank 1, and the tank The control means 50 mixes the hot water from the second hot water storage tank 2 and the water supplied from the first water supply bypass pipe 14 without changing the opening degree of the hot water mixing valve 11, and the hot water supply mixing valve 15 is connected to the hot water supply temperature sensor 17. Performs feedback control so as to detect the hot water supply set temperature.

  When the hot water flow rate counter 18 detects a flow rate less than the minimum operating amount (Yes in step S23), the tank control means 50 keeps the hot water mixing valve 11 and the hot water mixing valve 15 at the current opening until the next hot water supply. Wait.

  On the other hand, when the total amount of hot water supplied from the end of the boiling operation increases and the amount of hot water stored in the second hot water storage tank 2 decreases, the temperature detected by the hot water temperature sensor 13 gradually decreases and the hot water supply set temperature is reached. When the temperature falls below the predetermined temperature based on the above, No is determined in step S22, and the tank control means 50 increases the opening degree of the tapping water mixing valve 11 by one step toward the first tapping pipe 5 (step S24). Steps S22 and S24 are repeated until the temperature detected at 13 is equal to or higher than a predetermined temperature based on the hot water supply set temperature.

  Thus, when hot water is supplied, hot water is selectively or preferentially discharged from the second hot water storage tank 2 boiled first, so that the hot water in the second hot water storage tank 2 is reduced in time from boiling to hot water supply, The amount of natural heat radiation can be reduced, the hot water storage efficiency can be improved, and the hot water in the first hot water storage tank 1 that has been boiled up is discharged last, so that hot hot water can be secured for a long time. it can.

<Bath driving>
Next, the bath operation will be described. When the hot water filling switch 48 of the remote controller 45 is operated, the tank control means 50 opens the hot water filling valve 26, and hot water from the hot water mixing valve 11 passes through the bath hot water discharge pipe 20. The hot water from the hot water outlet pipe 20 and the hot water from the second water supply bypass pipe 21 are mixed with the bath set temperature, and the hot water from the hot water supply pipe 24 is passed through the hot water pipe 24. It is supplied to 29 bath return pipes 31. At this time, the tank control means 50 controls the hot water mixing valve 11 to preferentially discharge hot water from the second hot water storage tank 2 over hot water from the first hot water storage tank 1, as in the hot water supply operation. The opening degree of the bath mixing valve 22 is feedback controlled so that the temperature detected by the bath temperature sensor 33 becomes the bath set temperature.

  When the amount of hot water detected by the bath flow counter 25 reaches the hot water set amount preset by the remote controller 45, the tank controller 50 closes the hot water valve 26 and ends the hot water operation.

  The tank control means 50 is configured to perform a heat insulation operation for keeping the bath water at a bath set temperature for a predetermined time following the completion of the hot water filling operation. In this heat insulation operation, the bath circulation pump 32 is driven at regular time intervals. Then, the temperature of the bath water is detected by the bath temperature sensor 33. If the detected temperature is lower than the bath set temperature, the bath circulation pump 32 is continuously driven until the bath set temperature is detected by the bath heat exchanger 28. The hot water in the upper part of the first hot water storage tank 1 and the bathtub water are heat-exchanged to heat the bathtub water. On the other hand, if the detected temperature is equal to or higher than the bath set temperature, the driving of the bath circulation pump 32 is stopped and a certain time elapses. Until the bath circulation pump 32 is driven.

  This heat retention operation is generally performed after the evening when a considerable amount of time has passed since the end of the boiling operation, but there are a plurality of hot water in the first hot water storage tank 1 serving as a heat source for heating the bath water. The hot water in the second hot water storage tank 2 that does not serve as a heat source for the bath heat exchanger 28 is more selective than the hot water in the first hot water storage tank 1 that is boiled up and becomes the heat source for the bath heat exchanger 28. Or, since hot water is preferentially supplied, the amount of natural heat radiation in the elapsed time until it is used as a heat source is small, and the hot water in the first hot water storage tank 1 is replaced with hot water that has been naturally radiated in a large amount as in the prior art. Since there is nothing, the heating ability of bathtub water can be kept high.

<Drainage operation>
Next, a drain operation when draining hot water in the first hot water storage tank 1 and the second hot water storage tank 2 will be described.
When draining the water in the first hot water storage tank 1 and the second hot water storage tank 2, the worker closes the main tap of city water supplied to the water supply main pipe 7, shuts off the supply of new water, and manually operates the relief valve 10. To release. Then, after the drain switch 49 of the remote controller 45 is operated, the drain plug 39 is opened.

  When the drain switch 49 is operated, the tank control means 50 switches the boiling switching valve 42 to the boiling pipe 38 side, and connects the hot water mixing valve 11 to the first hot water pipe 5 and the second hot water pipe 6. As a semi-open state, the drainage state is assumed. This half-open state is preferably a 50% opening at which the opening on the first outlet pipe 5 side and the opening on the second outlet pipe 6 side of the hot water mixing valve 11 are equal, The opening area which connects the 1 hot water discharge pipe 5 side and the 2nd hot water discharge pipe 6 side becomes the maximum, and it becomes possible to supply more air to the 2nd hot water discharge pipe 6 side.

  In this drained state, the air sucked from the relief valve 10 is supplied to the upper portion of the first hot water storage tank 1 through the first hot water discharge pipe 5, and the first hot water storage tank 2 is smoothly drained, and the second hot water storage tank 2. The hot water filled between the second hot water pipe 6 and the relief valve 10 of the first hot water pipe 5 is drawn into the second hot water storage tank 2 at the same time by the suction force of the hot water drained from the bottom of the relief valve 10. The air sucked from the air is supplied to the upper part of the second hot water storage tank 2 through the first hot water pipe 5, the hot water mixing valve 11 and the second hot water pipe 6, and the second hot water storage tank 2 is smoothly drained. .

  Note that the drain switch 49 is not a single switch, and may be configured to function as a drain switch by operating a switch to which another function is assigned in a predetermined procedure.

  The present invention is not limited to the above-described embodiment, and can be modified without changing the gist of the invention. For example, the hot water mixing valve 11 is also used as a circulation switching means. However, the present invention is not limited to this, and the first boiling pipe and the second hot water storage branching from the boiling pipe 38 and connected to the upper part of the first hot water storage tank 1 independently of the first hot water discharging pipe 5 and the second hot water discharging pipe 6. A second boiling pipe connected to the upper part of the tank may be provided, and a circulation switching means independent of the tapping water mixing valve 11 that switches to select one of these may be provided, but the tapping water mixing valve 11 is used as the circulation switching means. It is also possible to reduce the number of pipes and the number of valve bodies by using the first hot water pipe 5 and the second hot water pipe 6 as a part of the heating circulation circuit 40, and it is possible to reduce the cost and simplicity. In the second hot water storage tank 2 It is preferred to be able to use up without Yosa hot water.

  In addition, the maximum valve opening is (100-X)% on the first outlet pipe 5 side and the second outlet pipe so that the first outlet pipe 5 and the second outlet pipe 6 are always in communication with the outlet hot water mixing valve 11. The 6th side may be limited to X%, the maximum valve opening may be limited to X% on the first outlet pipe 5 side, and (100-X)% on the second outlet pipe 6 side.

  Thus, since the first hot water storage tank 1 and the second hot water storage tank 2 are always in communication with the relief valve 10, the first hot water storage tank 1 and the second hot water storage tank 2 are surely drained even if there is a sudden power failure or the like. It can be carried out.

  Here, by limiting the maximum valve opening and the minimum valve opening, the first hot water discharge pipe 5 and the second hot water discharge pipe 6 communicate with each other even at the maximum valve opening and the minimum valve opening. The present invention is not limited to this, and the present invention can also be realized by opening a bypass flow path that communicates the first hot water discharge pipe 5 side and the second hot water discharge pipe 6 side inside the hot water mixing valve 11.

DESCRIPTION OF SYMBOLS 1 1st hot water storage tank 2 2nd hot water storage tank 3 1st water supply pipe 4 2nd water supply pipe 5 1st hot water pipe 6 2nd hot water pipe 10 Relief valve (atmospheric release valve)
11 Hot water mixing valve (circulation switching means)
34 Heating means 39 Drain plug 40 Heating circulation circuit

Claims (6)

  A first hot water storage tank for storing hot water, a second hot water storage tank, and heating means for boiling up the hot water in the first hot water storage tank and the second hot water storage tank, and an air release valve at the upper part of the first hot water storage tank and A hot water storage type hot water supply apparatus, wherein the hot water storage tank communicates with the upper part of the second hot water storage tank, and a drain plug communicates with the bottom of the first hot water storage tank and the bottom of the second hot water storage tank.   A first water supply pipe and a second water supply pipe for supplying water to the lower portions of the first hot water storage tank and the second hot water storage tank; a first hot water discharge pipe for discharging hot water from the upper portions of the first hot water storage tank and the second hot water storage tank; A tapping pipe, a tapping hot water mixing valve capable of mixing hot water from the first tapping pipe and the second tapping pipe when hot water is supplied, and the air opening branched from the first tapping pipe or the second tapping pipe The hot water storage type hot water supply apparatus according to claim 1, wherein a valve is provided and the hot water mixing valve is held at an opening degree at which the first hot water pipe and the second hot water pipe communicate with each other during drainage.   The atmosphere release valve is provided as an atmosphere release valve with an overpressure relief valve mechanism branched from the first hot water discharge pipe, and at the time of boiling, the heating means boils the second hot water storage tank and then the first hot water storage tank. The hot water storage type hot water supply apparatus according to claim 2, wherein the tank is boiled.   4. The hot water storage type hot water supply apparatus according to claim 3, wherein the hot water mixing valve closes between the first hot water discharge pipe and the second hot water discharge pipe at least during boiling of the second hot water storage tank.   A heating circuit for circulating hot water in the first hot water storage tank and the second hot water storage tank to the heating means and one of hot water in the first hot water storage tank and the second hot water storage tank are selectively circulated to the heating means. Circulation switching means for switching the flow path of the heating circulation circuit, and the heating circulation circuit provides a flow path from the heating means to the first hot water storage tank and the second hot water storage tank via the hot water mixing valve. Connected to the first and second tapping pipes, the first tapping pipe and the second tapping pipe are shared as a part of the heating circuit, and the circulation switching means is shared by the tapping mixing valve. The hot water storage type hot water supply apparatus according to claim 4, wherein   6. The hot water mixing valve according to any one of claims 2 to 5, wherein the first hot water pipe and the second hot water pipe communicate with each other even at the maximum valve opening and the minimum valve opening. The hot water storage type hot water supply apparatus described.

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