JP3144605B2 - Circulating water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circulation type hot water supply apparatus with a bypass for keeping a circulation heat when a hot water supply is stopped. The present invention relates to a circulation type hot water supply device for maintaining a temperature.

[0002]

2. Description of the Related Art There is known a water heater with a bypass in which a bypass pipe branched from a water supply side of a heat exchanger of a water heater and a tapping pipe provided on a tapping side of the heat exchanger are connected by a hot water mixing valve. Such a hot water supply device with a bypass mixes a high-temperature hot water that is sufficiently heated by a heat exchanger and passes through a tapping pipe and water that passes through a bypass pipe with a hot-water mixing valve so that hot water at a set temperature can be obtained. It is configured.

[0003] Therefore, a hot water supply device with a bypass can keep the heat exchanger itself at a high temperature, so that the rise time of hot water from supply of hot water to supply of hot water of a desired temperature is higher than that of a hot water supply device without a bypass. It has the characteristic of being short.

[0004] In addition, the end of the hot water supply pipe and the water supply pipe are connected by a return pipe to form a circulation path by a path of a hot water pipe, a return pipe, a water supply pipe, a heat exchanger, and a hot water pipe, and circulates in the circulation path. 2. Description of the Related Art There is known a circulation type hot water supply device in which a pump is provided to circulate hot water in a circulation path, and when hot water supply is stopped, hot water in the circulation path is maintained at a desired temperature by intermittent combustion control.

[0005] Such a circulating water heater can maintain hot water in the circulation path at a desired temperature even when the hot water supply is stopped. Therefore, in the hot water supply state, there is an advantage that hot water at a desired temperature can be supplied from the start of hot water supply. is there.

[0006]

However, the conventional bypass-type hot water supply system has a problem that it cannot cope with cooling of hot water from the heat exchanger outlet to the faucet. The hot tap water could not be quickly raised to the incoming cold tap water. In order to satisfy this demand, the advantages of the water heater with bypass and the circulation type water heater are combined, and the hot water in the circulation path is maintained at the desired temperature by intermittently burning in the hot water supply stopped state, and a large amount of water at the desired temperature from the start of hot water supply. Even if an attempt is made to supply hot and cold water, in the hot water supply stopped state, the temperature of the hot and cold water in the circulation path is maintained at a temperature close to the set temperature, so that the function of the hot water supply device with a bypass in the hot water supply state is impaired, There was a problem that a significant drop in the hot water temperature (undershoot) occurs after the circulation heating water flows out.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and supplies a hot water of a desired temperature even immediately after the start of hot water supply, and a recirculation system that does not cause a significant drop in the hot water temperature (undershoot). It is an object to provide a hot water supply device.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, a circulation type hot water supply apparatus according to the present invention is connected to a hot water supply pipe connected to a hot water supply pipe via a heat exchanger, and is connected to the hot water supply pipe at a mixing section. A bypass pipe connected to the water supply pipe at a branch, a mixing section for controlling a mixing ratio of hot water passing through the heat exchanger and water passing through the bypass pipe, and a hot water pipe downstream of the mixing section and upstream of the branch; A return pipe connected to the water supply pipe, and a circulating pump that sends out hot water from the hot water supply pipe to the water supply pipe through the return pipe;
A heating unit for heating the heat exchanger and a heating control unit for continuing heating by the heating unit even after the circulation pump is stopped are provided.

Further, the circulation type hot water supply apparatus according to the present invention comprises:
A hot water pipe connected to a hot water pipe through a heat exchanger, a hot water pipe connected to the hot water pipe at a mixing section and a hot water pipe connected at a branch section, and hot water passing through the heat exchanger and passing through a hot bypass pipe A mixing section for controlling a mixing ratio of water to be mixed, a return pipe connected to a hot water supply pipe downstream of the mixing section and a water supply pipe upstream of the branch section, and hot water of the hot water supply pipe is sent to the water supply pipe via the return pipe. Pump, a heating unit that heats the heat exchanger, a temperature setting unit that outputs a set temperature of hot water in the hot water supply pipe downstream of the mixing unit, and a temperature setting unit that maintains the temperature of hot water passing through the hot water supply pipe at the set temperature. A circulating stop condition judging unit for judging a circulating pump stop condition in a circulating hot water supply device comprising a required calorie calculating unit for calculating a required calorie, and controlling a heating amount of the heating unit based on the required calorie; The heating amount of the heating unit is determined based on the output of the condition determination unit. Characterized in that a heating control section for controlling a large amount of heat than the main heat.

Further, the heating control section of the circulation type hot water supply apparatus according to the present invention is characterized in that when the set temperature is equal to or higher than the predetermined temperature, the heating section does not continue heating after the circulation pump is stopped.

Further, the heating control section of the circulation type hot water supply apparatus according to the present invention controls the heating amount of the heating section to a required heating amount regardless of the output of the circulation stop condition judging section when the set temperature is equal to or higher than the predetermined temperature. It is characterized by.

[0012]

With the circulation type hot water supply apparatus according to the present invention, the hot water staying in the heat exchanger can be maintained at a high temperature by controlling the heating unit even after the circulation pump is stopped in the hot water supply stop state.

Further, since the heating amount of the heating unit is controlled to a heat amount larger than the required heat amount based on the output of the circulation stop condition judging unit, the temperature of the hot water staying in the heat exchanger when the circulation is stopped can be increased. .

When the set temperature is high, heating is not continued even after the circulation pump is stopped, or heating is not performed with a required amount of heat or more. Therefore, there is no possibility that hot water staying in the heat exchanger will boil.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a circulation type hot water supply apparatus according to the present invention. In FIG. 1, the circulation type hot water supply device 1
Water supply pipe 2, heat exchanger 3, hot and cold water mixing section 4, hot water supply pipe 5
A hot water tap 6 attached to a distal end of the hot water supply pipe 5, and a return pipe 8 disposed on a water inlet side of the hot water supply pipe 5 and the distal end of the hot water supply pipe 2.
And a circulation pump 7 provided in the middle of the return pipe 8, a water supply pipe 2-a heat exchanger 3-a hot and cold water mixing section 4-a hot water supply pipe 5-a return pipe 8
(Via circulation pump 7 on the way)-Water supply pipe 2 and water supply pipe 2
-Bypass pipe 10-Hot water mixing section 4-Hot water supply pipe 5-Return pipe 8
(Via the circulation pump 7 on the way)-a circulation path 9 forming a loop with two paths of the water supply pipe 2, a bypass pipe 10 connecting the water supply pipe 2 and the hot and cold water mixing section 4 by bypassing the heat exchanger 3,
A heating unit provided in the gas pipe 11 and provided with an electromagnetic valve 12 for supplying / stopping gas, a gas burner 14 for heating the heat exchanger 3, and a gas proportional valve 13 for adjusting the amount of gas to the gas burner 14; The water heater 1 includes a control unit 19 that controls and processes the entire operation of the water heater 1, and a controller operation unit 20 that sets various functions of the circulation water heater 1.

The water supply pipe 2 has a water supply temperature (Tc) detector 15 for detecting a water supply temperature Tc downstream of the water supply pipe 2 to which the return pipe 8 is connected, and a water quantity Q passing through the water supply pipe 2. A heat exchange outlet temperature (Th) for detecting an outlet temperature Th of the heat exchanger 3 is provided in the hot water supply pipe 5 in the water supply (Q) detecting unit 16.
The mixed hot water temperature T on the downstream side of the detection unit 17 and the hot and cold water mixing unit 4
and a mixed hot water temperature (Tm) detector 18 for detecting the temperature of the mixed hot water.

The hot water mixing section 4 mixes the high temperature hot water from the heat exchanger 3 and the water passing through the bypass pipe 10 at a predetermined mixing ratio under the control of the control means 19 and sends the mixed water to the hot water supply pipe. Hot water with the temperature set by the temperature setting section 20B of the controller operation section 20 is supplied from the hot water tap 6.

The driving / stopping of the circulating pump 7 is controlled by the control means 19, and when the hot water supply is stopped, the hot and cold water in the circulating passage 9 is circulated, and the temperature of the hot and cold water in the circulating passage 9 is set by the temperature setting section 20B. The temperature is kept close to the set temperature so that hot water can be supplied close to the set temperature from the start of hot water supply in the hot water supply state.

The solenoid valve 12 is controlled by a control means 19 to open / close the valve to supply / stop the gas passing through the gas pipe 11, open when hot water is supplied, and intermittently when hot water supply is stopped. The valve is repeatedly opened / closed according to the intermittent combustion cycle of the mode.

The gas proportional valve 13 is controlled by the control means 19 to control the opening of the proportional valve. The proportional valve is heated by an appropriate amount of combustion and supplied to the gas burner 14 so as to supply hot and cold water at the temperature set by the temperature setting section 20B. Adjust the feed rate.

The control means 19 is constructed on the basis of a microprocessor (not shown).
The circulation control means 30 includes drive / stop control of the circulation pump 7, and the heat quantity calculation means 40 calculates various heat quantities required by the heat control means 50. The heating control means 50 controls the solenoid valve 12 based on the heat quantity calculated by the heat quantity calculation means 40.
The control of the gas proportional valve 13 and the mixing unit control means 60 control the hot and cold water mixing unit 4 respectively.

The controller operation unit 20 includes a heat retention switch 20A for setting intermittent combustion control in a hot water supply stopped state and a temperature setting unit 20B for setting a hot water supply state and a mixed hot water temperature Tm in the hot water supply stopped state. 20a, the set temperature (Ts) signal 20b
Output to

Next, an outline of a hot water supply state (proportional combustion control) of the circulation type hot water supply apparatus 1 will be described. When the hot water tap 6 is opened to start hot water supply, the control means 19 determines that the hot water is being supplied, and sends a solenoid valve driving signal 50 a from the heating control means 50 to the solenoid valve 12 to open the solenoid valve 12. The calorie calculating means 40 of the control means 19 includes the set temperature (Ts) signal 20b from the temperature setting section 20B and the feedwater temperature (Tc) detecting section 1
Water temperature (Tc) signal 15a detected in step 5, water flow (Q)
The required heat amount FF is calculated based on the water amount (Q) signal 16a detected by the detection unit 16, and the heating control means 50 calculates the required heat amount F
The proportional valve drive signal 50b is output to the gas proportional valve 13 so that a large amount of heat corresponding to F is obtained, and the gas amount is adjusted so that an appropriate combustion amount is obtained from the gas burner 14.

The calorie computing means 40 computes a corrected calorie F by compensating the required calorie based on the mixed hot water temperature (Tm) signal 18a detected by the mixed hot water temperature (Tm) detector 18. Corrects the valve opening of the gas proportional valve 13 with the proportional valve drive signal 50b corresponding to the corrected heat amount F to correct the combustion amount of the gas burner 14, and calculates the heat amount until the mixed bath temperature Tm matches the set temperature Ts. The operation of the heating control continues.

The mixing section control means 60 of the control means 19 includes a set temperature (Ts) signal 20b and a feed water temperature (Tc) signal 15
a, the valve opening degree (the heat exchanger 3 side and the bypass pipe 10 side) of the hot and cold water mixing section 4 is calculated based on the heat exchange outlet temperature (Th) signal 17a and the mixed hot water temperature (Tm) signal 18a, and the calculation result Is sent to the hot and cold water mixing section 4 to appropriately mix the hot water at the heat exchange outlet temperature Th from the heat exchanger 3 and the water supply temperature Tc from the bypass pipe 10 to mix the hot water. Hot water of Tm (set temperature Ts) 6
Supplied from

As described above, the hot water supply device with the bypass provided with the bypass pipe 10 and the hot / water mixing section 4 has a temperature (heat exchange output temperature T) sufficiently higher than the set temperature Ts in the hot water supply state.
h) hot water is obtained, and water (water supply temperature Tc) from the bypass pipe 10 is mixed in the hot and cold water mixing section 4 to obtain a mixed hot water temperature Tm.
Hot water of (set temperature Ts) can be supplied. Therefore, the heat exchanger 3 can be maintained at a high temperature, and the time from the restart of hot water supply to the supply of hot water at the set temperature can be shortened.

Next, the operation in the hot water supply stop state (intermittent combustion control) will be described. When the hot water tap 6 is closed and the hot water supply is stopped in a state where the heat retaining switch 20A of the controller operation section 20 is set to ON, a circulation pump driving signal 30a is supplied from the circulation control means 30 of the control means 19 to the circulation pump 7, The circulation pump 7 operates and the hot and cold water stored in the circulation path 9 circulates through the circulation path 9. After a certain time has passed since the circulation of the hot water, the hot water in the circulation path 9 has reached the set temperature T.
When s is maintained, the circulation control means 30 stops outputting the circulation pump drive signal 30a, and the circulation pump is stopped.

The mixing unit control means 60 of the control means 19
Is supplied to the hot and cold water mixing valve 4 from the
The hot and cold water mixing valve 4 controls the temperature of the mixed hot water Tm by the controller operating unit 2.
The mixing ratio of the mixing valve is adjusted so as to be the set temperature Ts set by the temperature setting unit 20B of 0, and the hot water at the heat exchange outlet temperature Th and the water at the feed water temperature Tc of the bypass pipe 10 are mixed.

When the hot water supply is stopped, the circulation control means 30
Determines the circulation start condition and determines the circulation pump drive signal 30a.
Is output to drive the circulation pump 7 to circulate hot water. When the temperature of the circulating hot water reaches a predetermined temperature, the circulation stop condition is determined and the circulation pump 7 is stopped. In a state where the hot and cold water is circulating, the mixing section control means 60 outputs the mixing valve driving signal 60a to adjust the mixing valve of the hot and cold water mixing section 4 so that the temperature of the hot and cold water circulates at a predetermined temperature (for example, a set temperature). (Ts).

The calorie computing means 40 computes the calorie, such as the calorie necessary for intermittent combustion and the calorie calorie, based on signals from the water amount detector and the various temperature detectors provided in the circulation path 9, and the calculation result Is provided to the heating control means 50. The heating control means 50 calculates the intermittent combustion cycle based on the heat amount information from the heat amount
The proportional valve drive signal 50 is controlled so that the amount of combustion required to control the opening and closing of the valve 2 and to secure the high heat exchange outlet temperature Th is obtained.
b is supplied to the gas proportional valve 13 to control the amount of gas supplied to the gas burner 14.

The heating control means 50 selects a specific heat quantity calculated by the heat quantity calculation means 40 based on the circulation stop condition of the circulation control means 30, and outputs a solenoid valve drive signal 50a based on the specific heat quantity. To control the intermittent combustion cycle or output the proportional valve drive signal 50b to change the gas amount.

Further, when the set temperature Ts of the temperature setting unit 20B exceeds a predetermined temperature, the heating control means 50
The heating is controlled by the required amount of heat regardless of the circulation stop condition of the circulation control means 30.

FIG. 2 is a block diagram of the control means in the hot water supply stop state according to the present invention. In FIG. 2, the control means 19 includes a circulation control means 30, a heat quantity calculation means 40,
A heating control unit 50 and a mixing unit control unit 60 are provided.
The circulation control means 30 is configured to control driving / stopping of the circulation pump 7 and intermittent combustion, and includes a circulation start condition determination unit 31, a circulation stop condition determination unit 32, and a circulation pump control unit 33.

The circulation start condition judging section 31 determines the set temperature T
s, the start of circulation of the circulation pump 7 is determined based on the temperature information of the feed water temperature Tc and the mixed hot water temperature Tm, and the circulation start (J
o) The information 31a is output to the circulation pump control unit 33, and the circulation pump drive (Pc) signal 30 is output from the circulation pump control unit 33.
is output to drive the circulation pump 7. The circulation start condition is, for example, that the temperature of the mixed hot water Tm drops by a predetermined temperature ΔT1 from the feedwater temperature Tc (Tm <Tc−ΔT1), or that the temperature of the feedwater Tc drops by a predetermined temperature ΔT2 from the set temperature Ts (T
c <Ts−ΔT2) or when a predetermined time (t1 second) has elapsed after the intermittent combustion heating was stopped.

The circulation stop condition judging section 32 determines the set temperature T
s, the supply water temperature Tc, and the required amount of heat FF, which will be described later, to determine the circulation stop, and the circulation stop (Jc) information 32a.
To the post-combustion control unit 51 of the circulation pump control unit 33 and the heating control unit 50, and outputs the circulation pump stop (Pc) signal 30a from the circulation pump control unit 33 to stop the driven circulation pump 7. Constitute. The circulation stop condition is, for example, when the supply water temperature Tc is higher than the set temperature Ts (Tc> Ts) for more than a predetermined time (t2 seconds), or when the required heat amount FF is set to the minimum heat amount Fmin1. Less than (FF <Fmin1)
It is assumed that the time continues beyond a predetermined time (t3 seconds).

The calorie computing means 40 includes a target temperature setter 41 for outputting set temperature (Ts) information 41a corresponding to the set temperature (Ts) signal 20b from the temperature setter 20B, a required calorie calculator 42, a corrected calorie calculator. A unit 43, a specific calorific value calculating unit 44, a calorific value selecting unit 45, and a proportional / intermittent mode selecting unit 46 are provided.

The required calorie computing section 42 includes a target temperature setting section 4
1 based on the set temperature (Ts) information 41a, the water quantity (Q) signal 16a from the water quantity detection unit 16 and the water supply temperature (Tc) signal 15a from the water supply temperature detection unit 15 FF = Q × (Ts−Tc) is calculated, and the required heat amount (FF) information 42 a is supplied to the corrected heat amount calculation unit 43 and the proportional / intermittent mode selection unit 46.

The correction calorie calculation unit 43 calculates the set temperature (Ts)
The required heat quantity FF is corrected based on the information 41a, the required heat quantity (FF) information 42a and the mixed hot water temperature (Tm) information 18a from the mixed hot water temperature detection unit 18, and the corrected heat quantity (F) information 4
3a is sent to the calorie selection unit 45. The correction calorie F can calculate the feedback calorie based on the difference between the set temperature Ts and the mixed hot water temperature Tm, thereby absorbing the variation of the efficiency and gas pressure of the heat exchanger 3, the water volume and the variation of various temperature detectors. It can be calculated by adding the required heat quantity FF to this feedback heat quantity.

The specific calorie computing section 44 includes a heating control means 50.
The post-combustion (Nc) information 51a and the corrected calorific value (F) information 43a from the post-combustion control unit 51 are fetched, and the corrected calorific value F is calculated using a conversion table preset in correspondence with the corrected calorific value (F) information 43a. Larger, proportional
The intermittent mode selection unit 46 converts the heat into a specific heat amount Fc of such a size as to select the proportional combustion mode, and sends the specific heat amount (Fc) information 44a to the heat amount selection unit 45 when the Nc information exists.

The calorie selection unit 45 selects one of the correction calorie F and the specific calorie Fc in accordance with predetermined conditions, and uses the selected calorie as a selected calorie (Fo) signal 45a as the intermittent combustion cycle calculator 54 of the heating control means 50. And proportional valve controller 55
Send to The predetermined condition is that the post-combustion (Nc) information 51a does not exist and the specific combustion operation
c) When the information 44a is not provided to the heat amount selection unit 45, the correction heat amount F is selected, and when the specific heat amount (Fc) information 44a is supplied to the heat amount selection unit 45, the specific heat amount Fc is selected. .

The proportional / intermittent mode selection section 46 monitors the magnitude of the selected heat quantity Fo supplied from the heat quantity selection section 45, and
When the selected heat amount Fo is equal to or smaller than a predetermined lower limit of heat amount (corresponding to the lower limit combustion amount) in the proportional combustion (hot water supply) state, the intermittent combustion mode (Ha) information 46a is used as the intermittent combustion cycle calculation unit of the heating control means 50. 54 and the proportional valve control unit 55.

As described above, the calorie computing unit 40 selects either the intermittent combustion control or the proportional combustion control based on the value of the selected calorie Fo, and performs the intermittent combustion based on the corrected calorie F obtained by correcting the required calorie FF. Or based on the specific amount of heat Fc.

The heating control means 50 includes a post combustion control unit 5
1, heating start / stop condition judging section 52, solenoid valve driving section 5
3. An intermittent combustion cycle calculator 54 and a proportional valve controller 55 are provided. The post-combustion control unit 51 receives the supply of the circulation stop (Jc) information 32a output based on the stop condition determination of the circulation stop condition determination unit 32 of the circulation control unit 30,
The post-combustion (Nc) information 51a is output to the specific calorific value calculating unit 44 and the heating start / stop condition judging unit 52 of the calorific value calculating means 40 for a predetermined time to execute and output the calculation of the specific caloric value Fc and execute the heating stop. Delay. Further, the post combustion control unit 51 receives the supply of the set temperature information 41a from the target temperature setting unit 41 of the calorie computing unit 40, and if the set temperature Ts exceeds a predetermined temperature Tsk stored in advance, The configuration is such that the combustion (Nc) information 51a is not output.

Therefore, the set temperature Ts exceeding the temperature Tsk
Is input, the execution of the calculation of the specific heat amount Fc, the output, and the execution delay of the heating stop are not performed.

The heating start / stop condition judging section 52 judges the condition of heating start or heating stop, and outputs heating start / stop condition judgment (Kc) information 52 a to the solenoid valve driving section 53. The determination of the heating start / stop condition is performed based on the required heat amount FF, the water amount Q, the set temperature Ts, and the supply water temperature Tc,
For example, the required heat quantity FF is set to a preset lower limit heat quantity Fmin.
2 (FF> Fmin2) for a predetermined time (t4
Sec), if the water amount Q exceeds the lower limit water amount Qmin2 set in advance (Q> Qmin2), a heating start / stop condition judgment to open the solenoid valve (Kc)
The information 52 a is configured to be output to the solenoid valve driving unit 53. On the other hand, for example, when the required heat amount FF is equal to or less than the preset minimum heat amount Fmin1 (FF ≦ Fmin1), when the supply water temperature Tc exceeds the set temperature Ts (Tc> Ts) for a predetermined time (t5 seconds), or When the water amount Q is equal to or less than the preset minimum water amount Qmin1 (Q ≦ Qmin1), the heating start / stop condition determination (Kc) information 52a for closing the electromagnetic valve is output to the electromagnetic valve driving unit 53. Constitute. The heating start / stop condition determination unit 52
Receives the post-combustion (Nc) information 51a from the post-combustion control unit 51, and determines the heating start / stop conditions (Kc) for closing the solenoid valve while the Nc information 51a is being input. Does not output information 52a. Therefore, even if the heating stop condition is satisfied within a predetermined time during which the Nc information 51a is output after the circulation stop condition is satisfied, the closing of the solenoid valve is not immediately performed, but is performed with a delay.

The solenoid valve driving section 53 is based on the heating start / stop condition judgment (Kc) information 52a from the heating start / stop condition judgment section 52 and the intermittent combustion cycle (T) information 54a from the intermittent combustion cycle calculation section 54. The combustion time (T1) of the combustion cycle T (combustion time T1 + fire extinguishing time T2) is determined by the solenoid valve 12
The solenoid valve 1 is supplied by supplying a solenoid valve drive (Dc) signal 50a so as to close the solenoid valve 12 during the fire extinguishing time (T2).
2 is controlled to open and close.

When the intermittent combustion mode (Ha) information 46a is supplied from the proportional / intermittent mode selecting section 46 of the calorific value calculating means 40, the intermittent combustion cycle calculating section 54 receives the signal from the calorific value selecting section 45 of the calorific value calculating means 40. Selective heat (Fo) signal 45
a, a heat amount Fo-intermittent period T conversion table previously set in a memory such as a ROM, and a heat amount F
intermittent period T corresponding to o (combustion time T1 + fire extinguishing time T
2), and outputs the intermittent combustion cycle (T) information 54 a to the solenoid valve driving unit 53.

Like the intermittent combustion cycle calculating section 54, the proportional valve control section 55 has a heat amount previously set in a memory such as a ROM based on the intermittent combustion mode (Ha) information 46a and the selected heat amount (Fo) signal 45a. Referring to the Fo-valve opening degree Hc conversion table, the table is converted into the valve opening degree Hc corresponding to the heat quantity Fo, and the proportional valve drive (Hc) signal 50b is converted to the gas proportional valve 13.
Output to

The mixing section control means 60 includes a mixing valve opening calculation section 61 and a mixing valve control section 62. The mixing valve opening calculation section 61 includes a set temperature information 41a and a feed water temperature (Tc) signal 1
5a, the mixing valve opening Me is calculated on the basis of the mixed hot water temperature (Tm) signal 18a and the heat exchange outlet temperature (Th) signal 17a from the heat exchange outlet temperature detector 17, and the mixing valve opening Me is calculated.
The information 61a is output to the mixing valve control unit 62, and the mixing valve control unit 62 sends a mixing valve drive (Mc) signal 60a corresponding to the mixing valve opening (Me) information 61a to the hot and cold water mixing unit 4.

Thus, in the intermittent combustion control state,
Circulation stop (Jc) information 32 from the circulation stop condition determination unit 32
When a is output, the circulation pump 7 is stopped,
The specific heat amount calculation unit 44 is driven for a predetermined time via the post combustion control unit 51 to select the specific heat amount Fc larger than the correction heat amount F and the proportional combustion mode, and the gas proportional valve 13 is controlled to adjust the gas amount. As a result, a combustion amount corresponding to the specific heat amount Fc is generated from the gas burner 14. Therefore, the hot water staying in the heat exchanger and the heat exchanger itself can be maintained at a high temperature, and the temperature rise of the hot water when restarting hot water supply can be accelerated.

If the set temperature Ts exceeds a predetermined temperature Tsk stored in advance, the combustion based on the specific heat amount Fc and the continuation of heating after the circulation pump is stopped are not performed. The water is not heated.

In this embodiment, the heating is continued at a specific amount of heat equal to or more than the amount of heat required to obtain the hot water for the set time Ts for a predetermined time after the circulation pump is stopped. In this case, the heating and the driving of the circulation pump may be continued for a predetermined time, and during this predetermined time, the heating may be performed with a specific heat amount equal to or more than the heat amount necessary to obtain hot water at the set temperature Ts. In this embodiment, the temperature of the hot water in the heat exchanger is increased by controlling the valve opening of the proportional valve according to the specific calorific value. It is also possible to increase the temperature of the hot water in the heat exchanger by adopting a configuration in which the combustion time is increased.

[0053]

As described above, in the circulating hot water supply apparatus according to the present invention, when the circulating pump is stopped, combustion of the heating section is controlled based on a specific amount of heat, so that heat exchange significantly higher than the mixed hot water temperature Tm. The outlet temperature Th can be obtained, and the features of the hot water heater with bypass can be utilized in the circulation type hot water heater.

Therefore, even if the state shifts from the hot water supply stop state to the hot water supply state, a large amount of hot water can be supplied at a desired temperature from the start of hot water supply without causing significant undershoot.

When a set temperature exceeding the predetermined temperature is input, the combustion control based on the specific amount of heat and the continuation of heating after the circulation pump is stopped are not performed.

Therefore, it is possible to prevent the heat exchange outlet temperature from unnecessarily rising when the hot water supply is stopped, and to prevent the boiling water from flowing out at the start of the hot water supply.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a circulation type hot water supply apparatus according to the present invention.

FIG. 2 is a block diagram of a control unit in a hot water supply stop state according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circulating hot water supply apparatus 2 Water supply pipe 3 Heat exchanger 4 Hot water mixing part 5 Hot water supply pipe 6 Hot water tap 7 Circulation pump 8 Return pipe 9 Circulation path 10 Bypass pipe 11 Gas pipe 12 Electromagnetic valve 13 Gas proportional valve 14 Gas burner 15 Water supply temperature ( Tc) detecting section 16 water quantity (Q) detecting section 17 heat exchange outlet temperature (Th) detecting section 18 mixed hot water temperature (Tm) detecting section 19 control means 20 controller operating section 20A heat retaining switch 20B temperature setting section 30 circulation control means 31 circulation Start condition determination unit 32 Circulation stop condition determination unit 33 Circulation pump control unit 40 Heat amount calculation means 41 Target temperature setting unit 42 Required heat amount calculation unit 43 Corrected heat amount calculation unit 44 Specific heat amount calculation unit 45 Heat amount selection unit 46 Proportional / intermittent mode selection unit Reference Signs List 50 heating control means 51 post combustion control unit 52 heating start / stop condition judgment unit 53 solenoid valve drive unit 5 Intermittent combustion period calculation portion 55 proportional valve controller 60 mixer control means 61 mixing valve opening calculating section 62 mixing valve controller

Continuation of the front page (72) Inventor Kiyotaka Nakano 431-1 Uozakihama-cho, Higashinada-ku, Kobe-city, Hyogo Prefecture Inside (72) Inventor Tetsuro Takada 43-1, Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo Japan Nippon Yupro Stock In-house (56) References JP-A-5-60337 (JP, A) JP-A-3-13061 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24H 1/10 302

Claims (4)

(57) [Claims] 1. A hot water supply pipe connected to a water supply pipe via a heat exchanger, a bypass pipe connected to the hot water supply pipe at a mixing section and connected to the water supply pipe at a branch section, and passing through the heat exchanger. A mixing section for controlling a mixing ratio of hot water to be supplied and water passing through the bypass pipe; a return pipe connected to the water supply pipe downstream of the mixing section and the water supply pipe upstream of the branch section; A circulating pump that feeds hot water from the hot water supply pipe to the water supply pipe via a heating unit that heats the heat exchanger, and a heating control unit that continues heating by the heating unit even after the circulation pump is stopped. A circulation type hot water supply device characterized by the above-mentioned. 2. A hot water supply pipe connected to a water supply pipe via a heat exchanger, a bypass pipe connected to the hot water supply pipe at a mixing section and connected to the water supply pipe at a branch section, and passing through the heat exchanger. A mixing section for controlling a mixing ratio of hot water to be supplied and water passing through the bypass pipe; a return pipe connected to the water supply pipe downstream of the mixing section and the water supply pipe upstream of the branch section; A pump that feeds the hot water from the hot water supply pipe to the hot water supply pipe, a heating unit that heats the heat exchanger, and a temperature setting unit that outputs a set temperature of the hot water in the hot water supply pipe downstream from the mixing unit. A required calorie calculation unit for calculating a required calorie for maintaining a temperature of hot water passing through the hot water supply pipe at the set temperature, and a circulating hot water supply device for controlling a heating amount of the heating unit based on the required calorie. In the determination of the stop condition of the circulation pump A ring stop condition determination unit, circulating water heater characterized by comprising a heating control unit that controls a large amount of heat than the heat requirements of the heating amount of the heating portion based on the output of the circulation stop condition determination unit. 3. The heating control unit according to claim 1, wherein when the set temperature is equal to or higher than a predetermined temperature, the heating unit does not allow the heating unit to continue heating after the circulation pump is stopped.
The circulation type hot water supply device as described. 4. The heating control unit controls the heating amount of the heating unit to the required heat amount regardless of an output of the circulation stop condition determining unit when the set temperature is equal to or higher than a predetermined temperature. The circulation type hot water supply device according to claim 2.