JPH1114148A - Hot-water supplier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quicken the start of hot water supply, and besides, supply hot water safely, by equipping a hot-water supplier with a controller which has controls for stoppage not performing the heating of a heat exchanger by a heating means, when an air detector using a thermistor and a freezing preventive heater detects air bite. SOLUTION: A thermistor 31 and a freezing preventive heater 37 are attached in opposition in the same position of the water pipe in the vicinity of the exit of a heat exchanger 10, and an air detector 15 using those thermistor 31 and the freezing preventive heater 37 is heated by performing current application for a certain time to the freezing preventive heater 37 after measurement of reference temperature by a thermistor 31 after start of air detection, and then, it is stopped, and it is heated again, and the temperature after reheating is measured. Then, the difference between the measured temperature after heating and the reference temperature is found, and it is compared with the preset water-air judgment temperature difference. When, it is judged to be in air bite condition by the comparison result, it is so arranged as not to perform the heating of the heat exchanger 10 by the controls 26 at stoppage of a controller 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply apparatus which can supply hot water at the start of hot water supply.

[0002]

2. Description of the Related Art Conventionally, there is a hot water supply apparatus of this type as shown in FIG. 21 (for example, Japanese Patent Publication No. 4-9972). In FIG. 1, reference numeral 1 denotes an instantaneous water heater, and a hot water supply port 2 and the instantaneous water heater 1 are connected by a hot water supply pipe 3. A hot water supply valve 4 is provided in front of the hot water supply port 2, and the hot water supply valve 4 of the hot water supply pipe 3 is provided.
A drain pipe 5 branches from the upstream side of the drain pipe, and the drain pipe 5 is provided with a drain valve 6. Further, a temperature detecting section 7 is provided at a branch of the drain pipe 5 from the hot water supply pipe 3, and the hot water supply control section 9 compares the set temperature of the temperature setting device 8 with the temperature of the temperature detecting section 7 to supply hot water. The valve 4 and the drain valve 6 are controlled.

When the temperature of the hot water detected by the temperature detector 7 at the time of the hot water supply request is within the allowable range of the set temperature of the temperature setting device 8, the hot water valve 4 is opened and the hot water in the hot water pipe 3 is supplied to the hot water inlet 2. Supply and if out of tolerance, drain valve 6
The hot water in the hot water supply pipe 3 is discarded from the drain through the drain pipe 5, and hot water having a temperature within an allowable range is always supplied from the hot water supply port 2.

[0004]

However, in the above-described conventional hot water supply apparatus, when the temperature of hot water is out of an allowable range, for example, low when the hot water is requested, the drain valve 6 is opened and the hot water supply pipe 3 is opened.
In order to perform the operation of discarding the hot water inside from the drain,
There is a problem that the time until the hot water is supplied cannot be greatly improved. Further, it is necessary to install the hot water supply valve 4, the drain pipe 5, the drain valve 6, the temperature detecting section 7 and the like by performing piping work and wiring work on site, and the installation is troublesome, and the hot water supply valve which is not necessary in a normal hot water supply device. 4, there is also a problem that members such as a drain pipe 5, a drain valve 6, and a temperature detector 7 are required.

[0005] The present invention is to solve the above-mentioned problems, the improvement of the hot water supply device itself, early at the start of hot water supply,
Another object of the present invention is to provide a hot water supply device that can safely supply hot water.

[0006]

SUMMARY OF THE INVENTION The present invention provides a heat exchanger, a heating means for heating the heat exchanger, a heating adjusting means for adjusting the heating, a temperature detecting means for detecting a temperature near the heat exchanger, The flow detecting means for detecting the flow, the air detecting means for detecting the air bite in the heat exchanger by using a thermistor or another detector provided near the heat exchanger outlet, the flow detecting means does not detect the flow of water. At the time, when the temperature detected by the temperature detecting means falls below a predetermined temperature, the heating control means is controlled to start heating the heat exchanger by the heating means, and when the temperature reaches a preset time or temperature, the heating is stopped. When the air detector detects an air bite, the controller has a stop control unit that does not perform heating of the heat exchanger, and the temperature detected by the temperature detection unit becomes lower than a predetermined temperature while the hot water supply is stopped. When it comes to heating Control the means to start heating the heat exchanger by the heating means, stop the heating when the preset time or temperature is reached, prevent the heat exchanger from cooling when the hot water supply is stopped, In some cases, hot water can be quickly supplied to the terminal, and when the air detector detects an air bite, it does not heat the heat exchanger, preventing it from burning and keeping it inside the heat exchanger. The steam is filled to prevent danger or the like due to an abnormal temperature rise at the start of hot water supply.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a heat exchanger in which a water supply pipe and a hot water supply pipe are connected, heating means for heating the heat exchanger, and heating adjustment means for adjusting heating by the heating means. A temperature detecting means for detecting a temperature in the vicinity of the heat exchanger, a flow detecting means for detecting a flow of water, and a thermistor and an anti-freezing heater provided with an air bite in the heat exchanger near the heat exchanger outlet. When the temperature detected by the temperature detecting means becomes equal to or lower than a predetermined temperature when the flow of water is not detected by the air detecting means and the flow detecting means, the heating control means is controlled to heat the heat exchanger by the heating means. A controller having a stop control unit that stops heating when a preset time or temperature is reached, and stops heating when the air detector detects an air bite, and does not heat the heat exchanger by the heating unit. Configuration with Is shall.

When the flow of water to the heat exchanger is stopped when the hot water supply is stopped, the flow detecting means detects that the flow of water is stopped, and when the temperature detected by the temperature detecting means falls below a predetermined temperature, the heating means detects the stop. By starting heating of the heat exchanger and stopping the heating when a predetermined time or temperature is reached,
Prevents the heat exchanger from cooling when hot water supply is stopped, and enables quick supply of hot water to the terminal at the time of hot water supply at the time of re-hot water supply, and when the air detector detects air entrapment, By not performing the operation of starting heating of the heat exchanger by the heating means, heating is performed when air is trapped in the heat exchanger at the beginning of installation or after draining to prevent freezing, Are prevented from being fired.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the thermistor of the air detecting means and the temperature detecting means for detecting the temperature near the heat exchanger are commonly used. The cost can be reduced by reducing one to one. Since the air detection operation is performed only when the hot water supply operation is stopped, the operation of the temperature detection means for measuring the outlet temperature of the heat exchanger during the hot water supply operation is not hindered, and the function of the temperature detection means is thermistor 2 There is no difference from the two cases.

According to a third aspect of the present invention, in addition to the configuration of the first aspect, the thermistor and the anti-freezing heater are mounted opposite to each other at the same position of the water pipe near the heat exchanger outlet. Thus, the thermistor and the anti-freezing heater can be arranged at the shortest distance, and the temperature rise in the water pipe / water pipe due to heating of the anti-freezing heater can be detected at high speed and remarkably by the thermistor. Therefore, the presence / absence of water in the water pipe can be determined in a short time and accurately.

[0011] The invention according to claim 4 is the first invention.
In addition to the configuration of the present invention, the air detection means, after the start of air detection,
Reference temperature T by thermistor₀After measuring the
Immediately after the power is turned on for a certain period of time,
Temperature T after heating again₁Is measured and the temperature T after the heat is generated₁And reference temperature T
₀The difference ΔT between the temperature and the predetermined temperature difference ΔT _aWhen
Compare ΔT> ΔT_aIn the case of, it is determined that the air is in
≤ΔT_aIn the case of, it is determined that there is water. And heat exchange
Prevents empty firing as it can reliably determine the presence of water in the vessel
Can be

According to a fifth aspect of the present invention, in addition to the configuration of the first aspect, the air detecting means includes:
Reference temperature T ₀ and after a certain performs energization time heating is not heating stopped to antifreeze heater was measured by the thermistor, after a certain time ΔL elapses, the heat generation after temperatures T ₁ measures the heating after temperatures T ₁ again and the reference for comparison with the preset water air determined temperature difference [Delta] T _a difference [Delta] T between the temperature T ₀ ΔT> ΔT _a is determined and in the case of [Delta] T ≦ [Delta] T _a is determined as the air biting state is water. Since the presence or absence of water in the heat exchanger can be reliably determined, it is possible to prevent dry burning.

According to a sixth aspect of the present invention, in addition to the configuration of the first aspect, the air detecting means comprises:
Energization of the antifreeze heater, thermistor temperature T _s detecting the repeat thermistor temperature T _s and the elapsed time t measured results water air determined thermistor temperature time that is set previously obtained thermistor temperature temporal change rate dT _s / dt than in Compared with the change rate b, if dT _s / dt> b, it is determined that the air is caught, and if dT _s / dt ≦ b, it is determined that there is water. Since the presence or absence of water in the heat exchanger can be reliably determined, it is possible to prevent dry burning.

According to a seventh aspect of the present invention, in addition to the configuration of the first aspect, the air detecting means includes:
After energizing the anti-freezing heater for a certain period of time and stopping heat generation,
After a certain time ΔL course, thermistor temperature T _s detecting the repeat thermistor temperature T _s and the elapsed time t measured results water air determined thermistor temperature time that is set previously obtained thermistor temperature temporal change rate dT _s / dt than in Compared with the change rate c, if dT _s / dt ≦ c, it is determined that the air is caught and d
If T _s / dt> c, it is determined that there is water. Since the presence or absence of water in the heat exchanger can be reliably determined, it is possible to prevent dry burning.

The invention according to an eighth aspect is the invention according to the first aspect, further comprising the step of:
Energization of the antifreeze heater, integrated value heat storage heat of the thermistor from the measurement results of the repeated thermistor temperature T _s and the elapsed time t detected by the thermistor temperature ^{_{T s ∫ t 0 dT s ·}} dt as determined preset water air discriminated Thermistor heat storage e
Compared to determine the case of ^{_{∫ t 0 dT s · dt>}} e it determines that the air chewing state, in the case of ^{_{∫ t 0 dT s · dt ≦}} e is water. Since the presence or absence of water in the heat exchanger can be reliably determined, it is possible to prevent dry burning.

According to a ninth aspect of the present invention, in addition to the configuration of the first aspect, the air detecting means includes:
After energizing the anti-freezing heater for a certain period of time and stopping heat generation,
Thermistor temperature T _s repeat the detection of the thermistor temperature T _s
Compared with the elapsed time integral value of the thermal storage heat of the thermistor from the measurement results of the ^t ∫ t ₀ dT _s · dt as determined preset water air discriminated thermistor thermal storage heat f ^{_{and, ∫ t 0 dT s · dt}} >
For f is determined that the air biting ^{_{state, ∫ t 0 dT s · dt}} ≦ f
In the case of, it is determined that there is water. Since the presence or absence of water in the heat exchanger can be reliably determined, it is possible to prevent dry burning.

The invention according to claim 10 is the first invention.
In addition to the configuration of the invention, the air detection means, after air detection starting, thermistor temperature T repeatedly detected by the thermistor temperature T _s for a predetermined time ΔF around constant performs energization time heating is not heating the end of the anti-freeze heater integrated value from the thermal storage heat thermistor _s elapsed time t measured results of ∫Δ ^F ₀ dT _s ·
determined as dt, and compared with a preset water air discriminated thermistor thermal storage heat g, in the case of ∫Δ ^F 0dT _s · dt> g is determined that the air chewing state, in the case of ∫Δ ^F 0dT _s · dt ≦ g It is determined that there is water. Since the presence or absence of water in the heat exchanger can be reliably determined, it is possible to prevent dry burning.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic configuration diagram of a hot water supply apparatus in Embodiment 1 of the present invention. In FIG. 1, a water supply pipe 11 and a hot water supply pipe 12 are connected to a heat exchanger 10. The water supply pipe 11 is provided with a water amount detector 13 which is a flow detecting means for detecting inflow of water into the heat exchanger 10, and a water temperature detector 14 for detecting a water temperature. The pipe at the outlet of the heat exchanger 10 is provided with a thermistor 31 for detecting air entrapment and an air detector 15 utilizing a freeze prevention heater 37. A bypass pipe 16 is provided to bypass the heat exchanger 10 and connect the water supply pipe 11 and the hot water supply pipe 12. The bypass pipe 16 has a mixing ratio of hot water from the heat exchanger 10 and water from the bypass pipe 16. Is provided with a water proportional valve 17. The water proportional valve 17 is a valve that balances the water pressure by adjusting the current to the solenoid, and adjusts the opening degree of the bypass pipe 16 to adjust the amount of water passing therethrough. It is a normally open type that is retained.

The hot water supply pipe 12 near the heat exchanger 10 is provided with a hot water temperature detector 18 as a temperature detecting means, and a water quantity control valve 19 and a mixed water temperature detector 20 are provided after the junction of the bypass pipe 16. Is provided. The hot-water supply pipe 12 is further connected to a hot-water supply pipe 22 outside the hot-water supply apparatus main body 21 and communicates with a hot-water mixing tap 23 provided at a terminal. The controller 24 has a timer 2
5, signals from various sensors are taken in, and signals and operation outputs to various actuators are output. The controller 24 is provided with a hot water temperature setter 25 constituted by a volume and a stop-time control unit 26. The heat exchanger 10 is heated by a gas burner 27 as a heating means, and a gas proportional valve 28 is provided as a part of a heating adjustment means for adjusting a gas amount to the gas burner 27. The gas is turned on and off by a main solenoid valve 29 which constitutes another part of the heating control means. In this embodiment, the fuel is described as gas, but other fuel such as petroleum may be used.

The mounting portion of the air detector 15 is configured as shown in FIG. The air detector 15 is configured such that a thermistor 31 protected by a protective tube 30 is filled with a filler 32 and a lead wire 33 is exposed to the outside. It is attached to a water pipe 36 at the outlet of the ten. The freeze prevention heater 37 is attached to the water pipe 31 so as to face the thermistor 31. Then, the anti-freezing heater 37 is caused to generate heat, and the temperature is measured from the resistance value of the thermistor 31.
From the change in the state of heat transfer from 7 to the thermistor 31, it is determined whether or not the surroundings are water or air.

Next, the operation of this embodiment will be described. The operation is shown in the flowchart of FIG. If the power switch is turned on and <S1> and the heating switch is turned on <S2>, a mode is entered in which the heat exchanger 10 can be heated when the hot water supply is stopped. In this state, when the flow rate of water detected by the water amount detector 13 exceeds a predetermined value (for example, 2 l / min), the hot water mixing tap 23
Is determined to have been opened and enters the normal hot water supply mode <S
3> Supply hot water at a set temperature. Also, the hot water temperature detected by the hot water temperature detector 18 is compared with the set temperature,
The water temperature of the water temperature detector 14 and the value of the water amount detector 13 are taken in, the water proportional valve 17, the water amount control valve 17, and the gas proportional valve 28 are adjusted, and hot water at a desired temperature is supplied from the hot water supply pipe 22 <S4>. When the flow rate of water detected by the water amount detector 13 is equal to or less than a predetermined value (for example, 1.5 l / min) or when the hot water supply is stopped <S3>, the heat exchanger 1 when the hot water supply is stopped is stopped.
A heating mode to zero is possible.

Here, when the air detector 15 detects the air bite, the control is shifted to the heating stop mode for stopping the control,
The heating of the heat exchanger 10 by the burner 27 is not performed <S
5>. After a sufficient time has passed after the heating, the ambient temperature can be detected. When the temperature of the heat exchanger 10 rises abnormally, the temperature is detected complementarily. When the temperature detected by the hot water temperature detector 18 falls below a predetermined lower limit value when the air detector 15 has not detected the air bite (S6), when the entire hot water supply device is cold, the operation is stopped. Control unit 2
6 judges and advances the heating mode when the flow is stopped.
The lower limit value to be compared with the hot water temperature detector 18 is about 50 ° C., and when the temperature detected by the hot water temperature detector 18 is equal to or lower than the lower limit value, the process proceeds to the next step of the heating mode when the flow is stopped. <S6>. When the temperature detected by the hot water temperature detector 18 falls below the lower limit value, first, the heating time set by the timer 25 is read <S7>.

Next, the water temperature detected by the water temperature detector 14 and the current water temperature stored in the memory at the time of the previous hot water supply are read (S8). This is to judge how many times the supply water temperature is and to correct the heating time and the heating start temperature.If the water temperature is high, the time is short, the temperature is low, and if the water temperature is low, the time is Heat exchanger 10 so that the temperature is longer
The time for heating is corrected <S9>. Then, it is useful to supply hot water having a temperature as close as possible to the set temperature via the hot water supply pipe 12 at the time of re-water supply. Next, the original solenoid valve 29 is opened <S11>, and at the same time, the timer 25 starts counting time (S1).
2> The ignition of the gas proportional valve 28 is performed by opening the opening of the gas proportional valve 28 to the state of the opening 1 that facilitates ignition (S13).

Next, the ignition is confirmed, and the opening of the gas proportional valve 28 is reduced to the state of the opening 2 (S14). This opening corresponds to the minimum opening in a state where normal hot water supply is performed. Even when heating is performed at this minimum opening, the load is small, and the temperature of the heat exchanger 10 gradually increases. Go. In addition, when the minimum heating amount can be taken extremely low as a hot water supply device, a method of keeping the temperature detected by the hot water temperature detector 18 constant is also possible. If the temperature detected by the hot water temperature detector 18 during the heating of the heat exchanger 10 shows an abnormal change gradient, it is determined that air has caught in the heat exchanger 10 or that the heating is abnormal, and the heating is stopped <S15. 〉. The lower limit, which is a predetermined value for judging the start of heating, is T ₁ = 50 ° C. The upper limit T ₂ is set to 60 ° C. so that a person does not get burned even if touched. The heating time is 5 seconds under standard conditions (water temperature 15 ° C., mixed water temperature 40 ° C.), and correction is made according to the water temperature as described above.

If the timer 25 exceeds a predetermined time (5 seconds or a correction value of 5 seconds), it is considered that the time is up, and
The operation enters the stop operation <S16>. In the event that the timer 25 fails or the capacity control of the gas burner 27 fails and the temperature detected by the hot water temperature detector 18 exceeds the upper limit (70 ° C.), the original solenoid valve 29 is immediately given priority to the temperature. <S17>. In addition, the air detector 1
If the temperature detected in step 5 exceeds the upper limit value (70 ° C.), a stop operation for closing the original solenoid valve 29 immediately with priority on temperature is started (S18). When the heating is stopped, the original solenoid valve 29 is closed <S19>, and thereafter, after the heating is stopped, the combustion is not performed until the temperature detected by the hot water temperature detector 18 becomes equal to or lower than the lower limit value which is the predetermined temperature. Has stopped.

With the above operation, the temperature of the hot water when the hot water supply is stopped is maintained at a constant value, and the system is ready for hot water supply. Therefore, assuming a general household hot water supply device, in a conventional hot water supply device, in a system having a pipe length of about 5 m, it is normal that hot water is supplied in about 15 seconds after twisting a faucet of a terminal. However, according to the embodiment of the present invention, it can be reduced to about 5 seconds.

In the conventional hot water supply apparatus, it takes about 10 seconds for the hot water supply apparatus itself to rise due to the amount of retained water and the like and about 5 seconds to push out the amount of water retained in the piping. Since the rise time of the apparatus itself can be shortened, only the time for pushing out the staying water in the pipe is required.

Second Embodiment FIG. 4 shows a second embodiment. FIG.
FIG. 4 is a schematic configuration diagram of a hot water supply device according to a second embodiment of the present invention. The thermistor 31 of the hot water temperature detector 15 is used in common with the thermistor 38 of the hot water temperature detector 18 for detecting the temperature near the heat exchanger 10. The air detection operation is performed only when the hot water supply operation is stopped.
The operation of the hot water temperature detector 18 for measuring the outlet temperature of 0 is not hindered, and the function of the hot water temperature detector 18 is not different from the case where the thermistor 31 and the thermistor 38 are separate. Further, since the air detection is performed by the thermistor 31 and the anti-freezing heater 37, it is only necessary to change the software content of the controller 24 without increasing the number of parts as compared with the conventional water heater. Therefore, by sharing the thermistor of the temperature detection means and the thermistor of the air detection means required for performing hot water temperature control at the time of hot water supply, the number of thermistors can be reduced from two to one, and the cost can be reduced without lowering the performance. There is.

Third Embodiment FIG. 5 shows a third embodiment. FIG.
FIG. 9 is a schematic configuration diagram of an air detection unit 15 in Embodiment 3 of the present invention. The thermistor 31 and the anti-freezing heater 37 are attached to the water tube 36 at the same position of the water tube near the heat exchanger outlet, facing the same. Therefore, the thermistor 31 and the anti-freezing heater 37 can be arranged at the shortest distance, and the anti-freezing heater
The temperature rise in the water pipe 36 and the water pipe 36 due to the heating of the heater 37 can be rapidly and remarkably detected by the thermistor 31. Therefore, there is an effect that the presence or absence of water in the water pipe can be determined in a short time and accurately. Alternatively, the thermistor 31 and the anti-freezing heater 37 may be configured to be close to each other, so that the detection sensitivity of the temperature rise in the water pipe 36 by the thermistor 31 may be reduced to facilitate installation of the anti-freezing heater 37. Note that “close” means a position near the cylindrical direction and the circumferential direction of the water pipe 36.

(Fourth Embodiment) FIGS. 6 and 7 show a fourth embodiment. FIG. 6 is a principle diagram of the operation of detecting air entrapment, and FIG. 7 is a flowchart of air entrapment detection.

First, after detecting the reference temperature T ₀ (1),
Immediately after a predetermined performs energization time heating is not heating stopped to antifreeze heater, to determine the resistance value measured heat generation stop after the temperature T ₁ of the thermistor (2), to calculate the air chewing discrimination value ΔT = T ₁ -T ₀ , if previously instrument characteristics greater than the water-air discriminant value [Delta] T _a which has been determined by the determining air, is smaller than the water. In principle, when there is water, the heat capacity around the thermistor increases due to the presence of water, and the amount of heat transferred from the anti-freezing heater is absorbed by the water pipe and water, so that the temperature rise of the thermistor decreases. When air is present, the specific heat of air is much smaller than that of water, so the heat capacity around the thermistor is small, and the amount of heat transferred from the anti-freezing heater is absorbed by the water pipe and air. I have.

FIG. 8 shows data obtained by experiments performed by the inventors.
The elapsed time and the air bite determination value ΔT (deg) in the case where the anti-freezing heater is energized for 120 seconds and the heat is naturally radiated are plotted for the case where there is water in the water pipe and the case where there is air. It can be seen that the air bite determination value ΔT is larger when there is air than when there is water. In addition, even if there is water and air for a certain period of time after energization of the antifreeze heater, the thermistor temperature continues to rise due to the residual heat of the antifreeze heater, reaches a maximum value, and then decreases. The time required for the thermistor temperature to reach the maximum value after energization of the antifreeze heater is faster in air than in water. Therefore, when it is determined that there is water, the process proceeds to the heating mode, heating by the burner is started, and the system is immediately in a hot water supply system. If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

The anti-freezing heater energizing heating time is made longer by increasing the anti-freezing heater energizing heating time as the temperature around the thermistor increases, and the heating temperature is increased to reduce the influence of the thermistor ambient temperature. Therefore, the air bite determination value ΔT can be calculated more accurately by changing the anti-freezing heater energizing heating time depending on the temperature around the thermistor. In our experiments, the optimal anti-freezing heater energizing heating time is set as shown in the following table.

[0035]

[Table 1]

Fifth Embodiment FIGS. 9 and 10 show a fifth embodiment. FIG. 9 is a principle diagram of the operation of detecting air entrapment, and FIG. 10 is a flowchart of air entrapment detection. First, after detecting the reference temperature T ₀ (1), the anti-freezing heater is energized for a certain period of time to generate heat. After the power is turned off, the resistance value of the thermistor at the time when ΔL has elapsed is measured to determine the thermistor temperature T ₁ (2), and the air bite determination value ΔT = T ₁ −T ₀ is calculated and determined in advance according to the characteristics of the appliance. Put water / air discrimination value ΔT _a
If it is larger, it is judged as air, and if smaller, it is judged as water. In principle, even if there is water and air for a certain period of time after energization of the antifreeze heater, the thermistor temperature continues to rise due to the residual heat of the antifreeze heater, and when the maximum value of the presence of air is reached, the air bite that determines water / air The difference between the discrimination values ΔT is most noticeable. If the time until the temperature of the thermistor reaches the maximum value when there is air due to the residual heat is set to ΔL, the determination of water / air can be made more accurate.

In the example of FIG. 8, when the energization time of the anti-freezing heater is 120 seconds, ΔL = 60 seconds is the optimum set value. When it is determined that there is water, the process proceeds to the heating mode, in which heating by the burner is started, and the system is immediately in a hot water supply system.
If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

As in the case of the fourth embodiment, the anti-freezing heater energizing heating time is increased as the temperature around the thermistor increases, and the effect of the thermistor ambient temperature is reduced by increasing the heating temperature. The air bite determination value ΔT can be accurately calculated.

(Embodiment 6) FIG. 11 and FIG.
Show. FIG. 11 is a diagram illustrating the principle of operation for detecting air entrapment, and FIG.
It is a flowchart of a bite detection. Air bite detection star
From the thermistor temperature T (elapsed time t = 0)_sMeasure the
Preset time for anti-freezing heater energizing heating
Repeated n times until it exceeds tp, and then measured T
_sFrom the relationship between t and t, the temperature gradient during heating of the thermistor,
Thermistor temperature change rate over time dT _s/ Dt, and
Water / air discrimination thermistor determined in advance according to the characteristics of the equipment
Air if smaller than star temperature temporal change rate b, small
In this case, it is determined to be water. In principle, if there is water,
The heat capacity around the thermistor increases,
Heat transferred from the thermistor is absorbed by the water pipe and water.
The temperature rise becomes smaller and the temperature gradient becomes smaller. Place with air
In this case, the specific heat of air is significantly smaller than that of water.
Heat transfer from the anti-freezing heater due to a decrease in heat capacity around
Volume is absorbed by the water tube and air, resulting in a large temperature rise of the thermistor.
It takes advantage of the fact that the temperature gradient becomes large. water
If it is determined that there is
Heating is started and the system is ready for hot water. Air bite and size
If set, proceed to heating stop mode and heat with burner
Has been stopped, and it is possible to prevent empty heating of the heat exchanger.
You.

As in the case of the fourth embodiment, the anti-freezing heater energizing heating time is increased as the temperature around the thermistor increases, and the effect of the thermistor ambient temperature is reduced by increasing the heating temperature. the thermistor temperature temporal change rate dT _s / dt is allowed to be accurately calculated.

(Seventh Embodiment) FIGS. 13 and 14 show a seventh embodiment. FIG. 13 is a diagram illustrating the principle of operation for detecting air entrapment, and FIG. 14 is a flowchart of air entrapment detection. First, the anti-freezing heater is energized for a certain time to generate heat. After refused energization, from the time of the ΔL elapsed starts measuring the thermistor temperature T _s (elapsed time t = 0), repeated n times until exceeds the set time tq set in advance, then the measured T _s The temperature gradient at the time of heat radiation of the thermistor, that is, the thermistor temperature temporal change rate dT _s / dt is calculated from the relationship between t and t. It is determined to be water, and to be air if smaller. In principle, the temperature of the thermistor continues to rise due to the residual heat of the anti-freeze heater, even when there is water and air after the anti-freeze heater is energized. Utilize the fact that the temperature keeps rising for a time and reaches the maximum value. In other words, by setting ΔL to the time until the temperature of the thermistor reaches the maximum value when there is air due to residual heat, the temperature gradient after elapse of ΔL has a positive slope when there is water and a negative slope when there is air. Therefore, the determination of water / air can be made more accurate. If it is determined that there is water, the process proceeds to the heating mode, in which heating by the burner is started, and the system is immediately in the hot water supply system.
If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

As in the case of the fourth embodiment, the anti-freezing heater energizing heating time is increased as the temperature around the thermistor increases, and the influence of the thermistor ambient temperature is reduced by increasing the heating temperature. the thermistor temperature temporal change rate dT _s / dt is allowed to be accurately calculated.

(Eighth Embodiment) FIGS. 15 and 16 show an eighth embodiment. FIG. 15 is a principle diagram of the operation of detecting air entrapment, and FIG. 16 is a flowchart of air entrapment detection. Measuring the thermistor temperature T _s than air chewing detection start (elapsed time t = 0),
The anti-freezing heater energization heating is repeated n times until a preset time tr is exceeded, and then the measured T
_From the relationship between _s and t, the amount of heat stored during the heating of the thermistor is determined as an integral value ∫ ^tr ₀ dT _s · dt. . In principle, if there is water, the heat capacity around the thermistor increases due to the presence of water, and the amount of heat transferred from the anti-freezing heater is absorbed by the water pipe and water, so that the temperature rise of the thermistor decreases and the heat storage heat quantity ∫ ^tr ₀ dT _s · dt becomes smaller.

In the presence of air, the specific heat of air is much smaller than that of water, so the heat capacity around the thermistor is reduced, and the amount of heat transferred from the anti-freezing heater is absorbed by the water pipe and air. ∫ ^tr ₀ dT _s
-The fact that dt is increased is used. If it is determined that there is water, the process proceeds to the heating mode, in which heating by the burner is started, and the system is immediately in the hot water supply system. If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle. In addition,
The energization heating time of the anti-freezing heater is increased as the temperature around the thermistor increases as in the fourth embodiment, and the energization heating time of the anti-freezing heater is lengthened to increase the heating temperature, thereby reducing the effect of the thermistor ambient temperature and reducing the heat storage heat of the thermistor. ^tr ₀
The dT _s · dt has to be able to accurately calculate.

Ninth Embodiment FIGS. 17 and 18 show a ninth embodiment. FIG. 17 is a principle diagram of the operation of detecting air entrapment, and FIG. 18 is a flowchart of air entrapment detection. First, the anti-freezing heater is energized for a certain time to generate heat. After refusing the energization, and starts measuring the thermistor temperature T _s (elapsed time t =
0), n until the preset time ts exceeds
Times, and then the heat storage amount and the integrated value ∫ ^ts ₀ dT _s · dt during the heat release of the thermistor from the relationship between the measured T _s and t.
Is determined as air, and if it is larger than the preset water / air discriminating thermistor heat storage heat amount f, it is determined to be air; If it is determined that there is water, the process proceeds to the heating mode, in which heating by the burner is started, and the system is immediately in the hot water supply system. If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

As in the case of the fourth embodiment, the anti-freezing heater energizing heating time is increased as the temperature around the thermistor is increased, and the influence of the thermistor ambient temperature is reduced by increasing the heating temperature. The amount of heat stored in the thermistor ∫ ^ts ₀ dT _s · dt can be accurately calculated.

Embodiment 10 FIGS. 19 and 20 show Embodiment 1.
Indicates 0. FIG. 19 is a diagram showing the principle of operation for detecting air entrapment, and FIG.
8 is a flowchart of air bite detection. First, heat is generated performs energization of the antifreeze heater repeated detection of the thermistor temperature T _s for a predetermined time ΔF before and after when the heat generation. FIG.
In the example of No. 9, 1 / 2..DELTA.
The time before F is the start of the thermistor temperature measurement (t = 0), and the remaining thermistor measurement time ・ · ΔF is after the thermistor energization end time. After a certain time ΔF elapsed, the thermistor temperature T _s and the thermal storage heat of the thermistor than the measurement of the elapsed time t as compared with the integrated value ∫Δ ^F ₀ dT _s · dt as determined preset water air discriminated thermistor thermal storage heat g g If it is larger, it is determined that the air is caught, and if it is smaller, it is determined that there is water. In principle, Embodiment 8 and Embodiment 9 are combined, and the presence or absence of water is determined based on the amount of heat stored in the thermistor only before and after the end of heating of the thermistor where the temperature change is the most intense. If it is determined that there is water, the process proceeds to the heating mode, in which heating by the burner is started, and the system is immediately in the hot water supply system. If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

As in the case of the fourth embodiment, the anti-freezing heater energizing heating time is increased as the temperature around the thermistor increases, and the influence of the thermistor ambient temperature is reduced by increasing the heating temperature. the thermal storage heat ∫Δ ^F ₀ dT _s · dt of the thermistor is to be able to accurately calculate.

[0049]

As described above, according to the hot water supply apparatus of the present invention, the following effects can be obtained.

(1) It is detected by the flow detecting means that the flow of water to the heat exchanger has stopped when the hot water supply is stopped, and when the temperature detected by the temperature detecting means falls below a predetermined temperature, the heating is adjusted. Start heating the heat exchanger by the heating means by means,
By stopping the heating when a predetermined time or temperature is reached, the heat exchanger is prevented from being cooled when the hot water supply is stopped, and the time for heating the water in the heat exchanger when the hot water is resupplied is saved. In addition, hot water can be quickly supplied to the terminal at the time of hot water supply using only the hot water supply device main body. Also, when the air detector using an anti-freezing heater detects air entrapment, the heat exchanger is not heated by the heating means, so it can be used at the initial stage of installation or after draining to prevent freezing. Heating is performed when air is biting in the heat exchanger, and it is possible to prevent the heat exchanger from being fired and improve safety and maintain durability.

(2) By sharing the temperature detecting means for detecting the temperature near the heat exchanger and the thermistor of the air detecting means, the number of thermistors can be reduced from two to one, and the cost can be reduced. Also, since the air detection operation is performed only when the hot water supply operation is stopped, the operation of the temperature detection means for measuring the outlet temperature of the heat exchanger during the hot water supply operation is not hindered, and the function of the temperature detection means and the air detection The functions of the means can be compatible.

(3) Since the thermistor and the anti-freezing heater are mounted opposite to each other at the same position of the water pipe near the outlet of the heat exchanger, the thermistor and the anti-freezing heater can be arranged at the shortest distance. The temperature rise in the water tube / water tube due to heating of the heater can be rapidly and remarkably detected by the thermistor. Therefore, the presence / absence of water in the water pipe can be determined in a short time and with high accuracy, and it is possible to prevent empty heating of the heat exchanger.

(4) The air detecting means, after starting the air detection,
After measuring the reference temperature T ₀ with a thermistor, the anti-freezing heater is energized for a certain period of time to generate heat, and immediately after the heat generation is stopped,
After the heat generation after temperatures T ₁ measured again heating temperature T ₁ of the reference temperature T
Compared with a preset water air determined temperature difference [Delta] T _a difference [Delta] T between ₀ ΔT> ΔT _a ΔT is determined that the air biting state in the case of
≦ For [Delta] T _a If reliably determine the presence or absence of water in the heat exchanger water is determined that there because it is determined that there is a water started heating by burner proceeds to the heating mode, the immediate tapping system Yes. If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

(5) The air detecting means, after starting the air detection,
Reference temperature T ₀ and after a certain performs energization time heating is not heating stopped to antifreeze heater was measured by the thermistor, after a certain time ΔL elapses, the heat generation after temperatures T ₁ measures the heating after temperatures T ₁ again and the reference heat because in the case of comparing with a preset water air determined temperature difference [Delta] T _a difference [Delta] T between the temperature T ₀ ΔT> ΔT _a is determined in the case of [Delta] T ≦ [Delta] T _a is determined as the air biting state is water The presence or absence of water in the exchanger is reliably determined, and if it is determined that there is water, the process proceeds to a heating mode, in which heating by a burner is started, and the system is immediately in a hot water supply system. If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

(6) The air detecting means, after starting the air detection,
Energization of the antifreeze heater, thermistor temperature T _s detecting the repeat thermistor temperature T _s and the elapsed time t measured results water air determined thermistor temperature time that is set previously obtained thermistor temperature temporal change rate dT _s / dt than in Compared with the rate of change b, if dT _s / dt> b, it is determined that the air is caught, and if dT _s / dt ≦ b, it is determined that there is water. Therefore, the presence or absence of water in the heat exchanger is reliably determined. When it is determined that there is water, the process proceeds to the heating mode and heating by the burner is started,
Enter the immediate hot water system. If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

(7) The air detecting means, after starting the air detection,
After energizing the anti-freezing heater for a certain period of time and stopping heat generation,
After a certain time ΔL course, thermistor temperature T _s detecting the repeat thermistor temperature T _s and the elapsed time t measured results water air determined thermistor temperature time that is set previously obtained thermistor temperature temporal change rate dT _s / dt than in Compared with the change rate c, if dT _s / dt ≦ c, it is determined that the air is caught and d
If T _s / dt> c, it is determined that there is water. Therefore, the presence or absence of water in the heat exchanger is reliably determined. If it is determined that there is water, the process proceeds to the heating mode and heating by the burner is started. Enter the hot water system. If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

(8) After the air detection means starts the air detection,
Energization of the antifreeze heater, thermistor temperature T _s thermal storage heat ∫ ^t ₀ dT _s · dt look preset water air discriminated thermistor thermal storage heat detecting the repetitive thermistor from the measurement result of the thermistor temperature T _s and the elapsed time t Compare with e ∫ ^t ₀
In the case of dT _s · dt> e determined that the air bite state ∫ ^t ₀ dT
_{If s} · dt ≦ e, it is determined that there is water. Therefore, the presence or absence of water in the heat exchanger is reliably determined. If it is determined that there is water, the process proceeds to the heating mode, and heating by the burner is started. Enter the system. If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

(9) After the air detection is started, the air detection means
After energizing the anti-freezing heater for a certain period of time and stopping heat generation,
Thermistor temperature T _s repeat the detection of the thermistor temperature T _s
From the measurement result of the elapsed time t and the accumulated heat amount of the thermistor ∫ ^t ₀
dT _s · dt is obtained and compared with a preset heat / heat discrimination value f of the water / air discriminating thermistor. If ^t ₀ dT _s dt> f, it is determined that the air is in the air bite state. If ^t ₀ dT _s · dt ≦ f, Since it is determined that there is water, the presence or absence of water in the heat exchanger is reliably determined. If it is determined that there is water, the process proceeds to the heating mode, in which heating by the burner is started, and the system immediately enters the hot water supply system. If it is determined that the air has been caught, the process proceeds to the heating stop mode, in which the heating by the burner is stopped, and it is possible to prevent the heat exchanger from being idle.

[0059] (10) air detection means, after air detection starting, thermistor temperature T _s repeated detection of the thermistor temperature T _s for a predetermined time ΔF around constant performs energization time heating is not heating the end of the anti-freeze heater air for comparison ^{_{∫Δ F 0 dT s · dt>}} g water air discrimination thermistor thermal storage heat g of the measurement results from the thermal storage heat ∫Δ ^F ₀ dT _s · dt thermistor elapsed time t is set in advance determined to determines that the bite state to ^{_{∫Δ F 0 dT s · dt ≦}} g reliably determine heating mode if it is determined that the water is present the presence of water in the heat exchanger so is determined that there is a water case Heating by the advance burner is started and the system is ready for hot water. If it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped.
It is possible to prevent empty heating of the heat exchanger.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a hot water supply apparatus according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing an attached state of a thermistor of the water heater.

FIG. 3 is a flowchart of an operation of a main part of the water heater.

FIG. 4 is a configuration diagram of a hot water supply apparatus according to a second embodiment of the present invention.

FIG. 5 is a cutaway sectional view of an air detector used in a hot water supply apparatus according to Embodiment 3 of the present invention.

FIG. 6 is a diagram illustrating an operation of a main part of a hot water supply apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a flowchart of an operation of a main part of the water heater.

FIG. 8 is a view for explaining the principle of the hot water supply apparatus based on experimental data.

FIG. 9 is a diagram illustrating an operation of a main part of a hot water supply apparatus according to a fifth embodiment of the present invention.

FIG. 10 is a flowchart of an operation of a main part of the water heater.

FIG. 11 is a diagram illustrating an operation of a main part of a hot water supply apparatus according to a sixth embodiment of the present invention.

FIG. 12 is a flowchart of an operation of a main part of the water heater.

FIG. 13 is a view for explaining the operation of a main part of a hot water supply apparatus according to a seventh embodiment of the present invention.

FIG. 14 is a flowchart of an operation of a main part of the water heater.

FIG. 15 is a diagram illustrating an operation of a main part of a hot water supply apparatus according to an eighth embodiment of the present invention.

FIG. 16 is a flowchart of an operation of a main part of the water heater.

FIG. 17 is a diagram illustrating an operation of a main part of a hot water supply apparatus according to a ninth embodiment of the present invention.

FIG. 18 is a flowchart of an operation of a main part of the water heater.

FIG. 19 is a diagram illustrating an operation of a main part of a hot water supply apparatus according to Embodiment 10 of the present invention.

FIG. 20 is a flowchart of an operation of a main part of the water heater.

FIG. 21 is a configuration diagram of a conventional hot water supply apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Heat exchanger 11 Water supply pipe 12 Hot water supply pipe 13 Water quantity detector 15 Air detector 18 Hot water temperature detector (temperature detection means) 24 Controller 26 Stop control unit 27 Gas burner 28 Gas proportional valve (Heating adjustment means) 29 Source electromagnetic Valve 31 Thermistor (air detecting means) 37 Freezing prevention heater 38 Thermistor (temperature detecting means)

Claims (10)

[Claims] 1. A heat exchanger to which a water supply pipe and a hot water supply pipe are connected,
A heating unit that heats the heat exchanger, a heating adjustment unit that adjusts the heating unit, a temperature detection unit that detects a temperature near the heat exchanger, a flow detection unit that detects a flow of water, Air detecting means for detecting air entrainment in the heat exchanger using a thermistor and an anti-freezing heater provided near the outlet of the heat exchanger; and detecting the temperature when the flow detecting means does not detect the flow of water. When the temperature detected by the means becomes equal to or lower than a predetermined temperature, the heating control means is controlled to start heating the heat exchanger by the heating means, and the heating is stopped when the temperature reaches a preset time or temperature. In addition, a hot water supply device including a controller having a stop-time control unit that does not heat the heat exchanger by the heating unit when the air detection unit detects an air bite. 2. The hot water supply apparatus according to claim 1, wherein the hot water supply apparatus also serves as a temperature detecting means and a thermistor. 3. The hot water supply apparatus according to claim 1, wherein the thermistor is mounted at a position facing the anti-freezing heater. 4. An air detecting means, comprising:
The reference temperature T ₀To the antifreeze heater after measuring
Power for a certain period of time to generate heat,
Post-heating temperature T₁And the temperature T after the heat generation₁And reference temperature T₀When
The difference ΔT between the temperature and the predetermined temperature difference ΔT_aAnd ratio
ΔT> ΔT_aIn the case of, it is determined that the air is caught and Δ
T ≦ ΔT_aIn the case of, it is determined that there is water.
Or the hot water supply apparatus according to 3. 5. An air detecting means, comprising:
The reference temperature T ₀To the antifreeze heater after measuring
For a certain period of time and generate heat to stop the heat generation.
After the lapse of ΔL, the temperature T after the heat is generated again₁Measure the temperature after fever
Degree T₁And reference temperature T₀The difference ΔT from water air set in advance
Judgment temperature difference ΔT_aΔT> ΔT_aIf air bite
Is determined to be in the ON state, and ΔT ≦ ΔT_aIn the case of, it is determined that there is water
The hot water supply device according to claim 1, 2 or 3, wherein 6. The air detection means, after air detection start energization of the antifreeze heater, thermistor temperature T repeatedly thermistor temperature detection of _s T _s a thermistor temperature from the measurement result of the elapsed time t temporal change rate dT _s / look dt, and compared with a preset water air discriminated thermistor temperature temporal change rate b, in the case of dT _s / dt> b it determines that the air biting state,
dT _s / dt ≦ b water heater is determined according to claim 1, wherein the presence of water in the case of. 7. air detection means, after air detection start, after heating is stopped performs energization of a predetermined time to antifreeze heater, after a certain time ΔL elapsed, the thermistor temperature T _s repeated detection of the thermistor temperature T _s The thermistor temperature temporal change rate dT _s / dt is obtained from the measurement result of the elapsed time t, and is compared with a preset water-air discriminating thermistor temperature temporal change rate c. If dT _s / dt ≦ c, the air bite state And d
T _s / dt> and it determines claims if there is water in the c 1, 2
Or the hot water supply apparatus of 3. 8. The air detection means, after air detection start energization of the antifreeze heater, integrated value heat storage heat of the thermistor from the measurement results of the repeated thermistor temperature T _s and the elapsed time t detected by the thermistor temperature T _s ∫ ^t ₀ determined as dT _s · dt, and compared with a preset water air discriminated thermistor thermal storage heat e, ∫ ^t ₀ for dT _s · dt> e determines that the air biting state, ∫ ^t ₀ dT _s · dt 4. The hot water supply apparatus according to claim 1, wherein it is determined that there is water when ≤e. 9. The air detecting means energizes the anti-freezing heater for a certain period of time after the start of air detection and repeats the detection of the thermistor temperature T _s after the stop of heat generation, based on the measurement results of the thermistor temperature T _s and the elapsed time t. The integrated value of the heat storage heat of the thermistor ∫
^t ₀ determined as dT _s · dt, and compared with a preset water air discriminated thermistor thermal storage heat f, ∫ ^t ₀ For dT _s · dt> f is determined that the air biting state, ∫ ^t ₀ dT _s · dt 4. The hot water supply apparatus according to claim 1, wherein it is determined that water is present when ≤f. 10. air detection means, after air detection start, heat is generated performs energization of a predetermined time to antifreeze heater repeatedly detected by the thermistor temperature T _s for a predetermined time ΔF before and after when the heat generation, the thermistor temperature T _s the heat storage heat of the thermistor than the measurement of the elapsed time t and the calculated as the integral value ∫Δ ^F ₀ dT _s · dt, and compared with a preset water air discriminated thermistor thermal storage heat _{^{g, ∫Δ F 0dT s · dt}} > g of If it is determined that the air biting state, water heater determines claim 1, wherein the presence of water in the case of ∫ΔF0dT _s · dt ≦ g.