JP2928005B2 - Instant 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 an instant water heater in which an outlet of a set temperature can be obtained immediately after the start of use in an instant water heater system.

[0002]

2. Description of the Related Art An instant hot water supply apparatus of this type includes, for example, FIG.
As shown in the figure, the forward pipe 1 connecting the inlet side of the heat exchanger 3 heated by the gas burner 6 and the discharge side of the pump 5 and the return pipe 2 connecting the outlet side of the heat exchanger 3 and the suction side of the pump 5.
, Water is circulated by forming a loop-shaped circulation conduit, a hot water tap 2a is provided in the return pipe 2, and a water supply pipe 4 is connected to the outward pipe 1. This instant hot water supply device circulates water in the circulation pipe by the pump 5 when hot water is not supplied from the hot water tap 2a, and uses the gas burner 6 based on the temperature detected by the temperature sensor 8a.
The temperature of the water in the circulation pipeline is always maintained near the set temperature by controlling the amount of gas supplied to the circulation pipe. And hot water tap 2
When a is opened, the flow sensor 9 detects an increase in the flow rate, regards it as water supply, stops the pump 5, ignites the gas burner 6, or increases the amount of heating, and this water supply is heated by the heat exchanger 3 and the hot water tap 2a It is taken from hot water. In this state, the temperature sensor 8
The opening degree of the proportional solenoid valve 7 provided in the gas supply pipe is controlled based on the detected temperature b so that the temperature of the hot water from the hot-water tap 2a becomes the set temperature. According to such a technique, since water near the set temperature is circulated in the return pipe 2 provided with the hot water tap 2a, there is an advantage that tap water near the set temperature can be obtained immediately after the start of use.

In this type of hot water supply apparatus, a gas burner 6
In order to prevent the temperature of the hot water from dropping below a desired set value when the hot water is supplied beyond the heating capacity of the
Alternatively, an electromagnetic throttle valve is provided between this and the inlet side of the heat exchanger 3, and the opening degree of this electromagnetic throttle valve is set based on the set temperature or the temperature based on the set temperature or the supply water temperature so that the supply of water exceeding the heating capacity is not sent. It is also considered to control.

[0004]

However, since the fins and tubes of the heat exchanger have a heat capacity and a delay in heat transfer, even such an instantaneous hot water supply device has a large amount when the gas burner is ignited or when the gas amount is rapidly increased. There is a problem that the tapping temperature temporarily drops when the tapping is performed. This problem can be solved by providing a large hot water storage tank at the return pipe between the outlet side of the heat exchanger and the branch point to the hot water tap, but another problem is that the equipment becomes large and the manufacturing cost increases. Problems arise. An object of the present invention is to solve each of these problems simultaneously.

[0005]

For this purpose, the instant hot water supply apparatus according to the first aspect of the present invention has an inlet side of a heat exchanger 13 heated by a gas burner 30 as shown in FIGS. A loop-shaped circulation line 1 composed of a forward pipe 11 connecting a discharge side of a pump 14 and a return pipe 12 connecting an outlet side of the heat exchanger 13 and a suction side of the pump 14.
0, a hot water tap 16 branched from the middle of the return pipe 12
A water supply pipe 25 connected in the middle of the forward pipe 11 and a temperature sensor 42 provided on the return pipe 12 between an outlet side of the heat exchanger 13 and a branch position to the hot water tap 16. In the provided instant hot water supply apparatus, one end of the water supply pipe 25 is provided.
Between the connection position of the heat exchanger 13 and the inlet side of the heat exchanger 13.
The other end connected to the pipe 11 is connected to the temperature sensor 42 and the hot water supply.
The by-pass connected to the return pipe 12 between the stopper 16 and the branch position
Pass line 20, the bypass line 20, and the heat exchanger
13 on the circulation line 10
Total throttle valve 23 to be restricted and inlet of water supply pipe 25
Water provided between the heat exchanger 13 and the inlet side of the heat exchanger 13
Detecting devices 41, 45, and 46 ;
When the water supply state is detected by the temperature sensors 45 and 46, the gas is supplied to the gas burner 30 so that the temperature of the hot water detected by the temperature sensor 42 becomes a predetermined temperature that is higher by a predetermined value TA than the set tap temperature T. And the opening of the total throttle valve 23 is set to the minimum opening or in the vicinity thereof when the water inflow detecting devices 41, 45 and 46 do not detect the water inflow state. The control device 40 gradually increases the tapping temperature within a range where the tapping temperature does not fall below the tapping temperature set value T when the tapping water is detected.
And the high-temperature water provided at the one end side of the bypass pipe 20 and passing through the temperature sensor 42, and the low-temperature water from the bypass pipe mixed with the high-temperature water, and the hot water tap is set as the temperature of the tap water temperature setting value T. An automatic mixing valve 21 for supplying to the 16 side is provided.

The controller 40 of the instant hot water supply apparatus according to the present invention is characterized in that the total throttling is performed when the water input detecting devices 41, 45 and 46 stop detecting the water input state and the gas burner 30 stops burning. the opening of valve 23, until said hot water detected by the temperature sensor 42 drops to a predetermined temperature higher than the predetermined value T _a only smaller a value the hot water temperature setting value T the gas burner 30 is burned Is preferably maintained at the opening at the time of stopping, and thereafter, at or near the minimum opening.

Alternatively, in the instant hot water supply apparatus according to the first aspect of the present invention, there is provided a timer 47 for starting time measurement when the gas burner 30 stops burning because the water input detection devices 41, 45, and 46 no longer detect the water input state. The control device 40 further includes: a timer for controlling the opening degree of the total throttle valve 23 when the gas detection device 41, 45, 46 stops detecting the water inflow state and the gas burner 30 stops the combustion. It is preferable that the opening is maintained at the same level as when the gas burner 30 stopped the combustion until the measurement of the predetermined time is finished at 47, and the minimum opening is set at or near the minimum opening after the completion of the measurement of the predetermined time.

In the instant hot water supply apparatus according to a fourth aspect of the present invention, as shown in FIGS. 4 to 6, the inlet side of the heat exchanger 13 heated by the gas burner 30 and the discharge side of the pump 14 are connected. A loop-shaped circulating pipeline 10 composed of an outgoing pipe 11 and a return pipe 12 connecting the outlet side of the heat exchanger 13 and the suction side of the pump 14, and a hot water tap branched off from the middle of the return pipe 12 16, a water supply pipe 25 connected in the middle of the forward pipe 11, and a temperature sensor 42 provided on the return pipe 12 between the outlet side of the heat exchanger 13 and a branch position to the hot water tap 16. in immediate water heater comprising wherein the heat exchanger 13 the circulation pipe 1 the flow through the
0 and the water supply pipe 25
Water detecting devices 41, 45, 46 provided between the inlet side of the heat exchanger 13 and the inlet side of the heat exchanger 13;
Hot water temperature set value T in which the hot water temperature detected by 2 is set
The amount of gas supply to the gas burner 30 is controlled so that the opening degree of the total throttle valve 23 is set to the minimum opening degree when the water input detecting devices 41, 45, and 46 do not detect the water input state. It may be provided with a control device 40 that gradually increases the temperature in a range where the tap water temperature does not become equal to or lower than the tap water temperature set value T when the tap water detection device detects the tap water state.

[0009] The instant hot water supply apparatus according to claim 4 of the present invention comprises:
The control device 4 further includes a timer 47 that starts counting when the gas burner 30 stops burning because the water input detection devices 41, 45, and 46 no longer detect the water input state.
0 indicates the degree of opening of the total throttle valve 23 and the timer 47 measures the time of a predetermined time when the water input detecting devices 41, 45, and 46 stop detecting the water input state and the gas burner 30 stops burning. It is preferable to maintain the opening at the time when the gas burner 30 stops the combustion until the end, and set the opening to the minimum opening or near the minimum opening after the end of the predetermined time period.

[0010]

When the hot water tap 16 is closed and the water input detecting devices 41, 45, and 46 do not detect a water input state, the control device 40 of the instant hot water supply device controls the circulation line 10 by the pump 14. The amount of gas supplied to the gas burner 30 is controlled so that the temperature detected by the temperature sensor 42 of the circulating hot water becomes the hot water temperature set value T.
Is at or near the minimum opening. By this, hot water tap 1
The hot water having the hot water temperature set value T is circulated to the return pipe 12 near 6. If the hot water tap 16 is opened, the water detection devices 41, 45,
46 detects a water inflow state, and the control device 40 operates the gas burner 30 so that the hot water temperature detected by the temperature sensor 42 becomes a predetermined temperature that is higher by a predetermined value TA than the tap water temperature set value T.
The amount of gas supplied to the outlet is increased, and the opening degree of the total throttle valve 23 is gradually increased within a range where the tapping temperature does not fall below the tapping temperature set value T to increase the tapping amount. The automatic mixing valve 21 mixes the high-temperature water at the predetermined temperature passed through the temperature sensor 42 and the low-temperature water from the bypass pipe 20 to a temperature of the tap water temperature set value T, and supplies the hot water via a total throttle valve 23. Supply to the 16 side. Immediately after the incoming water detection devices 41, 45, and 46 detect the incoming water state, the total throttle valve 23 is at or near the minimum opening, so that even when the hot water tap 16 is suddenly opened greatly, the amount of hot water is immediately increased. However, it gradually increases with an increase in the opening of the total throttle valve 23.

[0011] In the immediate water heater according to claim 2, until the hot water temperature detected by the temperature sensor 42 drops to a predetermined temperature higher than the hot water temperature set value T by a certain value smaller than a predetermined value T _A is the total aperture Since the valve 23 is maintained at the opening when the gas burner 30 stops the combustion, the hot water
By opening 6, the total throttle valve 23 gradually increases from its opening. Similarly, the hot water supply device according to the third aspect is similar to the hot water supply device according to the present invention, until the timer 47 finishes measuring a predetermined time.
By opening 6, the total throttle valve 23 gradually increases from its opening.

A control device 40 for an instant hot water supply apparatus according to claim 4.
The hot water tap 16 is closed and the water input detection devices 41, 45,
When the hot water supply state is not detected at 46, the temperature detected by the temperature sensor 42 of the hot water circulating in the circulation pipe line 10 by the pump 14 becomes the tap water temperature set value T, similarly to the instant hot water supply device of claim 1. In this way, the amount of gas supplied to the gas burner 30 is controlled, and the total throttle valve 23 is set at or near the minimum opening. As a result, the return pipe 1 near the hot water tap 16
The hot water of the hot water temperature set value T is circulated to 2. When the hot water tap 16 is opened and the water detection devices 41, 45, and 46 detect the water inflow state, the control device 40 sends the gas to the gas burner 30 so that the hot water temperature detected by the temperature sensor 42 becomes the hot water temperature set value T. The supply amount is controlled and supplied to the hot-water tap 16 through the total throttle valve 23, and the opening degree of the total throttle valve 23 is gradually increased within a range where the tapping temperature does not become lower than the tapping temperature set value T to reduce the tapping amount. Increase. Immediately after the incoming water detection devices 41, 45, and 46 detect the incoming water state, the total throttle valve 23 is at or near the minimum opening, so that even when the hot water tap 16 is suddenly opened greatly, the amount of hot water is immediately increased. However, it gradually increases with an increase in the opening of the total throttle valve 23.

In the instant hot water supply apparatus of the fifth aspect, the total throttle valve 23 is opened when the gas burner 30 stops the combustion until the timer 47 finishes measuring the predetermined time, similarly to the instant hot water supply apparatus of the third aspect. If the hot water tap 16 is opened during that time, the total throttle valve 23 gradually increases from the opening degree.

[0014]

As described above, according to the first aspect of the present invention, even if the hot water tap is suddenly opened greatly when the gas burner is ignited or hot water is supplied, the hot water supply amount does not immediately increase and the minimum opening degree or the hot water supply amount does not increase. Since it gradually increases from that vicinity,
The tapping temperature does not drop temporarily regardless of the heat capacity of the fins or tubes of the heat exchanger or the delay in heat transfer. In addition, the control device gradually increases the opening of the total throttle valve and increases the amount of hot water within a range where the hot water temperature does not fall below the hot water temperature set value. There is no further decrease or the amount of hot water is restricted despite the heating capacity.

According to the second aspect of the invention, until the hot water temperature detected by the temperature sensor decreases to the predetermined temperature, the total throttle valve is maintained at the opening degree at which the gas burner stopped combustion. When the hot water tap is opened, the total throttle valve gradually increases from its opening degree, so when the hot water supply is repeatedly stopped in a short time, the hot water flow rate does not decrease each time, and the hot water temperature changes transiently. Since there is no further decrease, usability is improved. Claim 3
Similarly, in the instant hot water supply apparatus, if the hot water tap is opened before the timer finishes measuring the predetermined time, the total throttle valve gradually increases from its opening degree, so that the usability is similarly improved.

According to the fourth aspect of the invention, similarly to the first aspect of the invention, even when the hot water tap is suddenly and greatly opened at the time of ignition of the gas burner or hot water supply, the amount of hot water gradually increases from or near the minimum opening degree. However, the tapping temperature does not drop temporarily regardless of the heat capacity of the fins or tubes of the heat exchanger or the delay in heat transfer. Also, there is no possibility that the tapping temperature exceeds the heating capacity and the tapping temperature drops below the tapping temperature set value, and the tapping amount is not restricted despite the heating capacity. Also, in the invention of claim 5, similarly to the invention of claim 3, if the hot water tap is opened before the timer finishes measuring the predetermined time, the total throttle valve gradually increases from its opening degree. The ease of use in the case of frequently stopping hot water supply in a short time is improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment will be described with reference to FIGS. As shown in FIG. 1, the inlet side of the once-through heat exchanger 13 heated by the gas burner 30 is connected to the discharge side of the pump 14 via the forward pipe 11, and the outlet side of the heat exchanger 13 is connected to the return pipe 12. Are connected to the suction side of the pump 14 via the two pipes 11 and 12 to form a loop-shaped circulation pipe 10. A water supply pipe 25 is connected in the middle of the forward pipe 11, and a hot water tap 16 is branched in the middle of the return pipe 12 via a branch pipe 15. A plurality of branch pipes 15 and hot water taps 16 may be provided. The water supply pipe 25 is provided with a check valve 26 for preventing backflow from the instant hot water supply device to the water supply source side. Fuel gas is supplied to the gas burner 30 via a gas supply pipe 31 provided with a main solenoid valve 32 and a proportional solenoid valve 33.

The bypass pipe 20 provided between the outgoing pipe 11 and the return pipe 12 has a heat exchanger 13 at one end on the return pipe 12 side.
Is connected between the outlet side and the branch position to the hot water tap 16,
The other end on the outgoing pipe 11 side is connected between the connection position of the water supply pipe 25 and the inlet side of the heat exchanger 13. Automatic mixing valve 21 provided at the connection between bypass line 20 and return line 12
The first inlet 21a is connected to the return pipe 12 on the heat exchanger 13 side, the second inlet 21b is connected to the bypass pipe 20, and the outlet 21c is connected to the return pipe 12 on the hot water tap 16 side. The opening of the first inlet 21a side and the second inlet 21b side is controlled to open and close in opposite directions by the operation of the servomotor 22 as described later, so that the high-temperature water from the outlet side of the heat exchanger 13 And the mixing ratio of the low-temperature water from the bypass pipe 20 and the hot water having the tap water temperature set value T set by the remote controller 46 or the like is supplied to the return pipe 12 from the outlet 21c toward the hot-water tap 16 side. is there. The minimum opening of the first inlet 21a is not fully closed, but the minimum opening of the second inlet 21b is fully closed.

A check valve 18 for preventing backflow when the pump 14 is stopped is provided between the connecting position of the pump 14 and the feed pipe 25 at the connecting position of the feed pipe 25 and the bypass pipe 20 at the forward pipe 11. A first temperature sensor 41 is provided between the bypass line 20 and the first temperature sensor 41.
A flow sensor 45 for detecting a flow rate to the heat exchanger 13 is provided between the connection position of the heat exchanger 13 and the heat exchanger 13. The return pipe 12 between the heat exchanger 13 and the automatic mixing valve 21 has a heat exchanger 1
A tank 17 having a second temperature sensor 42 and an electric heater 35 is provided in this order from the third side. The heating capacity of the electric heater 35 is smaller than that of the gas burner 30. The return pipe 12 is provided with a total throttle valve 23 and a third temperature sensor 43 on the hot water tap 16 side near the automatic mixing valve 21. The total throttle valve 23 is a proportional solenoid valve having a predetermined minimum opening. In this embodiment, the branch pipe 15, the hot water tap 1
Each part except the part 6 and the return pipe 12 is provided in the main body casing shown by the two-dot chain line A. It is desirable that the branch pipe 15 be relatively short, and that a part of the return pipe 12 be extended to near a hot water tap 16 provided at a desired location such as a sink.

The above sensors 41 to 43 and 45, the servo motor 22 of the automatic mixing valve 21, the total throttle valve 23, the solenoid valves 32 and 33 of the gas burner 30, the electric heater 35 and the operating device 46 are provided by the instant hot water supply device. It is connected to an electronic control unit 40 for controlling the operation. The electronic control unit 40 includes a central processing unit (CPU) and a read-only memory (RO).
M), a writable memory (RAM), an interface, and the like, which perform hot water supply control, normal control of the total throttle valve 23, and the like, which are roughly described below. In addition, each code | symbol used for the following description is as follows. W: detected flow rate of the flow rate sensor 45 ΔW: rate of increase of the detected flow rate W T: tapping temperature set value t1: detected temperature of the first temperature sensor 41 t2: detected temperature of the second temperature sensor 42 t3: third temperature sensor 43 Detection temperature

The hot water supply control includes control of the proportional solenoid valve 33 including ignition of the gas burner 30 and control of the automatic mixing valve 21. In the former, the proportional electromagnetic valve 33 is slowly ignited and the gas burner 30 is gently ignited by an ignition plug (not shown). After the gradual ignition is completed, the opening of the proportional electromagnetic valve 33 is maintained at a temperature at which hot water is not discharged from the hot water tap 16. In the state (described later), the temperature t2 detected by the second temperature sensor 42 is controlled so as to be equal to the tapping temperature set value T set via the operation device 46, and the detection is performed in the tapping state in which tapping from the tap 16 is being performed. temperature t2, and controls so that the hot water temperature setting value T + T _a. Note that T _A
Is a predetermined value corresponding to the tapping temperature set value T, for example, T = 40 ° C.
In the case of, T _A = 25 ° C., and in the case of T = 60 ° C., T _A = 20 ° C.
The latter controls the opening degree of the automatic mixing valve 21 via the servomotor 22 so that the detected temperature t3 of the third temperature sensor 43 becomes the tapping temperature set value T. The electronic control unit 40 closes the main solenoid valve 32 and stops the operation of the gas burner 30 when the flow rate sensor 45 does not detect the predetermined flow rate.

Normal control of the total throttle valve 23 is as follows: A = constant / (set temperature of second temperature sensor 42−detected temperature
t1), however, the set temperature of the second temperature sensor 42, the insulation state as described above is hot water temperature set value T, the hot water state is T + T _A. The constant is determined according to the heating capacity of the water heater, for example, 400 for the water heater of No. 16 and 600 for the water heater of No. 24. If the detected flow rate W of the flow rate sensor 45 is not equal to or more than A, that is, if the heating capacity is not exceeded, the total throttle valve 23 is fully opened. That is, the total throttle valve 23 is throttled until the detected flow rate W becomes a value commensurate with the heating capacity.

Next, the operation of the first embodiment will be described.
When the power of the hot water supply apparatus is immediately turned on by the operation of a manual switch or a program timer provided on the operation device 46, the operation according to the flowcharts shown in FIGS. 2 and 3 is started. At this time, it is assumed that hot water is not discharged from hot water tap 16.

At the start of this operation, the detected flow rate W is approximately 0
Since the detected temperature t1 is equal to or lower than T-7 ° C., the CPU of the electronic control unit 40 advances the control operation from steps 100 and 101 to step 102, activates the pump 14, fully opens the total throttle valve 23, and sets the circulation pipe. The water in the passage 10 is circulated, the electric heater 35 is operated to heat the circulated water, the control operation returns from step 103 to step 101, and steps 101 to 103 are repeated. However, since W> 1.5 l / min is immediately obtained by the operation of the pump 14, C
The PU advances the control operation from step 103 to step 104, opens the main solenoid valve 32, sets the proportional solenoid valve 33 to a gentle ignition opening, ignites the gas from the gas burner 30, starts combustion, and passes through the heat exchanger 13. The heating of the circulating water is started, and after completion of the ignition, the gas burner 3 is operated by the proportional solenoid valve 33 so that the temperature t2 detected by the second temperature sensor 42 becomes the set value T of the hot water.
The gas supply amount to zero is controlled, and the control operation proceeds to step 105 while continuing this. Immediately after the start of operation, W is less than 7 liters / min, ΔW is relatively small, t1 is less than T-7, and t2 is T
+3, the CPU repeats steps 105 to 109, whereby the circulating water is supplied to the gas burner 3.
0 and gradually heated by the electric heater 35. When the detected temperature t1 of the first temperature sensor 41 is equal to or higher than T-7 ° C., the CPU proceeds from step 107 to step 120 in FIG.
The control operation proceeds.

The CPU closes the main solenoid valve 32 in step 120 to stop the combustion of the gas burner 30. In this state, the detected temperature t1 is a little over T-7 and T + 3 or less. The control operation proceeds to step 122, and then the pump 14 and the electric heater 35 are operated to set the total throttle valve 23 to the minimum opening degree, and then proceed to step 123. Then, the CPU proceeds to steps 121 to 12
Step 3 is repeated to heat the circulating water by the electric heater 35. In this state, the detected flow rate W of the flow rate sensor 45 is continuously maintained at 1.5 liter / min or more. If the detected temperature t1 exceeds T + 3 due to this heating, the CPU advances the control operation from step 121 to step 124, stops the operation of the pump 14 and the electric heater 35, and proceeds to step 125 with the total throttle valve 23 kept at the minimum opening. Proceed. In this state, the detected flow rate W of the flow rate sensor 45 becomes almost 0,
Since the detected temperature t1 of the temperature sensor 41 is approximately T + 3, steps 125 and 126 are repeated. Then, the temperature of the hot water in the circulation line 10 decreases due to the heat radiation, and the detected temperature
If t1 becomes equal to or less than T-3, the process proceeds from step 126 to step 1
Returning to step 23, steps 121 to 123 are repeated, and circulating heating is performed again by the electric heater 35. This is alternately performed, and the hot water temperature in the circulating conduit 10 is set at the tapping temperature set value T ± 3.
Kept at ° C. Since the amount of water in the circulation pipeline 10 and the tank 17 is relatively small, the heat retention state is reached when a predetermined time (for example, 15 minutes) elapses after the power supply of the hot water supply device is immediately turned on. In this state, the automatic mixing valve 21 has the first inlet 21a almost fully opened and the second inlet 21b almost completely closed. If the detected temperature t2 becomes equal to or higher than T + 3 ° C. during the repetition of steps 105 to 109 described above, the CPU advances the control operation from step 108 to step 110, and the main solenoid valve 3
2 is closed to stop the combustion of the gas burner 30, and the control operation proceeds from step 101 to the above-mentioned step 121 to be in a warm state.

When the hot-water tap 16 is opened in the heat-retaining state of steps 121 to 126, hot water having a tap water temperature set value T ± 3 ° C. circulating in the circulation pipeline 10 is discharged from the hot-water tap 16 and at the same time the hot water supply pipe. Since the cold water from 25 is supplied to the inlet side of the heat exchanger 13, the detection temperature t1 of the first temperature sensor 41 decreases, and t1 <T-7. Accordingly, the CPU advances the control operation from step 123 to step 130 to stop the operations of the pump 14 and the electric heater 35, and proceeds to step 131 so that the total throttle valve 23 is gradually opened from the minimum opening. If the hot water tap 16 is opened and the pump 14 is stopped, the detected flow rate W is usually 1.5 liter / min or more.
The control operation proceeds to step 132 to start hot water supply control,
The flow proceeds to the next step 133 after limiting the gradually increasing detection flow rate W to not more than 4 liters / min. Step 1
32 hot water supply control is slow to ignite the gas burner 30, as described above, the detection temperature t2 controls the proportional solenoid valve 33 such that the hot water temperature setting value T + T _A detected temperature t3 is tapping temperature setpoint T
The automatic mixing valve 21 is controlled so that If the detected temperature t2 of the second temperature sensor 42 is equal to or lower than the tapping temperature set value T, the CPU returns the control operation to step 131 and repeats steps 131 to 133. If t2> T, the CPU advances the control operation to step 134. Normal control of the total throttle valve 23 is performed. As described above, at the start of hot water supply, the total throttle valve 23 gradually opens from the minimum opening degree, and when the detected temperature t2 is equal to or lower than the hot water temperature set value T, the detected flow rate W is limited so as not to be 4 liter / min or more. Even when the plug 16 is suddenly opened, the amount of hot water is slowly increased and the amount of hot water does not become excessive. Therefore, even if there is a delay in the heat capacity or heat transfer due to the fins or tubes of the heat exchanger 13, the temperature of the hot water is reduced. Hardly falls below the set value T of the hot water.

Subsequently, the CPU performs the control operation in step 13.
4 to step 141 in FIG. 2, W> 1.5 l / min
That is, if tapping still continues, steps 141 and 1
42 is repeated to perform the hot water supply control and the normal control of the total throttle valve 23. Water temperature is hot water temperature set value T + T _A becomes flowing into the first inlet 21a of an automatic mixing valve 21 if Sugire transient state just after pouring begins, the automatic mixing valve 21 this hot water is controlled to the CPU from the bypass line 20 2nd entrance 21b
Is mixed with the cold water supplied to the hot water, and becomes hot water having the tap water temperature set value T.
It is taken from hot water. In this state, the opening degree of the total throttle valve 23 is fully opened unless the detected flow rate W of the flow rate sensor 45 is equal to or higher than the above-described A, and if the detected flow rate W is equal to or larger than A, the opening degree of the total throttle valve 23 is reduced. This prevents the amount of hot water from being limited despite the heating capacity, and prevents the hot water temperature from dropping below the hot water temperature set value beyond the heating capacity. If the hot water tap 16 is closed to stop tapping, the detected flow rate W
Becomes approximately 0, the CPU returns the control operation from step 141 to step 110, and returns to the gas burner 30 as described above.
Is stopped, and the process returns to step 101. In this case, if the detected temperature t1 is not lower than T-7, the control operation immediately proceeds from step 101 to step 121, where T
If it is -7 or less, steps 105 to 109 are repeated via steps 101 to 103 and step 104, and immediately the detected temperature t1 becomes T-7 or more. Become.

The hot-water tap 16 was opened in the warm state of steps 121 to 126, but the opening degree was small and the detected flow rate W was 1.5 / min.
If not reached, the CPU repeats steps 131 and 135 to gradually open the total throttle valve 23 to increase the detected flow rate W, and after W> 1.5 / min, the control operation proceeds to step 132. If the total throttle valve 23 is fully opened before W> 1.5 / min, the CPU returns the control operation from step 134 to step 102. In this case, the above-described step 10 is performed through steps 102 to 104.
State where steps 5 to 109 are repeated or steps 121 to 121
Hot water is supplied in the heat retaining state of 126.

In a state where steps 105 to 109 are repeated, the opening degree of the hot water tap 16 is increased, and the rate of increase ΔW of the detected flow rate is 2 liters / min or more or the detected flow rate W
Is 7 liters / min or more, the CPU executes the control operation from step 105 or step 106 to step 1.
Proceeding to 40, the operation of the pump 14 and the electric heater 35 is stopped, and proceeding from step 141 to step 142,
The same hot water supply control as that described above and the normal control of the total throttle valve 23 are performed. If the hot water tap 16 is widely opened at the same time as or before the power is turned on, the CPU proceeds to step 10.
From 0, the control operation proceeds to step 142 to immediately perform hot water supply control and normal control of the total throttle valve 23.

In the first embodiment, the total throttle valve 23 is set to the minimum opening in steps 122 and 124, and at the start of tapping, the total throttle valve 23 is always opened from the minimum opening in step 130. However, immediately after the gas burner 30 to close the water tap 16 is stopped fins and tubes of the heat exchanger 13 and becomes higher water temperature inside the tube at high temperatures (T + T _A), the hot water decreases gradually in the heat retaining state The temperature becomes a tapping temperature set value T ± 3 ° C., and the tap water temperature becomes a certain value (for example, a tapping temperature set value T + 3 ° C.) as time passes.
During this period, the tapping temperature does not drop transiently below the tapping temperature set value T without setting the total throttle valve 23 to the minimum opening. Therefore, the total detection temperature t2 of the second temperature sensor 42, while to decrease the temperature T + T _A immediately after the gas burner 30 to close the water tap 16 is stopped until the above value, which is controlled in step 122 and step 124 The opening of the throttle valve 23 may be the opening at the time when the flow rate sensor 45 stops detecting the flow and the gas burner 30 stops the combustion, and thereafter, may be the minimum opening. If the first embodiment is modified in this manner, the tapping flow rate does not decrease each time the tapping stop is frequently repeated in a short time, and the tapping temperature may transiently drop below the tapping temperature set value T. Because there is not, usability improves.

Further, the hot water tap 16 is closed and the gas burner 30 is closed.
The time during which the high hot water temperature (T + T _A ) immediately after the stop of the cooling is stopped is almost constant (for example, 6 minutes), so the hot water tap 16 is closed and the flow rate sensor 45 detects the flow rate. When the gas burner 30 has stopped running and the gas burner 30 has stopped burning, the timer 47 incorporated in the electronic control unit 40 is started, and the opening degree of the total throttle valve 23 controlled in steps 122 and 124 is determined by the timer 47 for a predetermined time (described above). The opening may be the opening at the time when the gas burner 30 stops the combustion until a predetermined time is measured, and thereafter, the opening may be the minimum opening. Also in this case, it is possible to improve the usability when frequently stopping hot water supply is repeated in a short time as described above.

In the above-described first embodiment, the state of incoming water is detected by the first temperature sensor 41. However, as shown by the two-dot chain line in FIG. It may be. Alternatively, the resistance of the circulation line 10 is adjusted by a throttle 19 or the like provided in series with the pump 14 so that the flow rate sensor 4
A certain value (for example, 2 liter / min) of the detection flow rate W of 5
, The flow rate sensor 45 can be used also as a water entry detection device. In this case, if the detected flow rate W exceeds the above-mentioned certain value, it is determined that the water has entered. Also,
The tall throttle valve 23 is connected to the circulation line 10 (water supply pipe 25
Between the connection portion of the bypass pipe 20 and the connection portion of the bypass pipe 20).
Good, but heat exchange is better if it is provided on the tapping side as in this embodiment.
The water pressure inside the vessel 13 increases, which is advantageous for preventing boiling.
Become.

Next, a second embodiment shown in FIGS. 4 to 6 will be described. As shown in FIG. 4, the structure of the second embodiment is obtained by removing the tank 17, the electric heater 35, the bypass line 20, the automatic mixing valve 21, and the third temperature sensor 43 from the first embodiment. Since other structures are the same, detailed description is omitted. Since the automatic mixing valve 21 is not provided in the second embodiment, the content of the hot water supply control is based on the second temperature sensor 42.
Is to control the opening of the proportional solenoid valve 33 so that the detected temperature t2 becomes the hot water temperature set value T. Total throttle valve 2
The normal control of No. 3 is substantially the same as that of the first embodiment, but the set temperature of the second temperature sensor 42 is the tap water temperature set value T as described above. Note that the electronic control unit 40 includes the flow sensor 4
5 is not detecting the predetermined flow rate, the main solenoid valve 32
Is closed to stop the operation of the gas burner 30.

Next, the operation of the second embodiment will be described with reference to the flow charts shown in FIGS. If the power of the hot water supply apparatus is immediately turned on in a state where hot water is not being supplied from the hot water tap 16, the CPU proceeds to steps 200 and 20 as in the first embodiment.
The control operation proceeds from step 1 to step 202, the pump 14 is operated, the total throttle valve 23 is fully opened, and the circulation line 10 is
Start the circulation of water inside. Next, the CPU proceeds to step 20.
3 and step 212 are repeated for 10 seconds, during which W
If> 1.0 liter / min, the control operation proceeds to step 205 after 5 seconds in step 204. If W> 1.0 l / min is not reached within 10 seconds, there is some abnormality, so the CPU advances the control operation to step 213 to stop the pump 14, displays the abnormality by a lamp or the like, and immediately activates the hot water supply device. Stop. As described above, immediately after the start of operation, W is less than 7 liters / min, ΔW is relatively small, t1 is less than T-7, and t2 is less than T + 3.
At 9, the main electromagnetic valve 32 is opened and the proportional electromagnetic valve 33 is set to a gentle ignition opening to ignite the gas burner 30 to start combustion, and the detected temperature t2 of the second temperature sensor 42 becomes proportional to the tapping temperature set value T + 2 ° C. The gas supply amount is controlled by the solenoid valve 33. Thereby, the circulating water passing through the circulation line 10 is gradually heated by the gas burner 30. And the first temperature sensor 4
If the detected temperature t1 of Step 1 is equal to or higher than T-7 ° C., the CPU proceeds from Step 207 to Step 215 of FIG.

Immediately after the start of operation of the hot water supply device, the detected temperature t1
When the temperature is low, the detected temperature t1 is lower than the tapping temperature set value T, and the CPU advances the control operation from step 215 to step 219 immediately. Detected temperature t1 is high during operation t1
If not <T, the CPU advances the control operation from step 215 to step 216 to stop the pump 14 and set the total throttle valve 23 to the minimum opening. However, since W = 0, the main electromagnetic valve 32 is closed and The combustion of the gas burner 30 stops. Then, Steps 217 and 218 are repeated, and if the temperature of the hot water in the circulation pipeline 10 decreases due to heat radiation and the detected temperature t1 becomes equal to or lower than T-3, the control operation proceeds to Step 219. In step 219, the pump 14 is operated and the total throttle valve 23 is set to the minimum opening degree.
The control operation proceeds to 0, and in step 220, as in step 203 described above, if W> 1.0 l / min within 10 seconds, the control operation proceeds to step 221; otherwise, the operation of the instant hot water supply device is stopped. .

In the state where hot water is not discharged from the hot-water tap 16, t 1
<T−7, so the CPU advances the control operation from step 221 to step 222. If t2 <T + 2, the CPU repeats steps 221 and 222, and t2 <T
If it is +2, the routine proceeds to step 223, where the combustion of the gas burner 30 is started, and the gas supply amount is controlled by the proportional solenoid valve 33 so that the temperature t2 detected by the second temperature sensor 42 becomes the tapping temperature set value T + 2 ° C. 221 to step 22
Repeat 4. As a result, the circulating water passing through the circulation line 10 is gradually heated by the gas burner 30, and when t2 <T + 3 is not satisfied, the CPU proceeds to step 225, closes the main electromagnetic valve 32, stops the combustion of the gas burner 30, and proceeds to step 225. 221 and return to step 221 and step 22
Repeat 2. If t2 <T + 2 due to heat radiation, the process proceeds to step 223 again, in which the gas burner 30 is operated to heat the circulating water. By repeating the above, the circulation line 10
The temperature of the hot water in the vicinity of the second temperature sensor 42 is kept between + 2 ° C. and + 3 ° C. based on the tapping temperature set value T. The temperature of the hot water in the vicinity of the branch pipe 15 of the return pipe 12 is slightly lowered to become near the tapping temperature set value T.

If the hot water tap 16 is opened in the warm state of steps 221 to 225, hot water near the tap water temperature set value T circulating in the circulation line 10 is discharged from the hot water tap 16 and simultaneously from the water supply pipe 25. Is supplied to the inlet side of the heat exchanger 13, so that the detection temperature t1 of the first temperature sensor 41 decreases, and t1 <T-7. As a result, the CPU advances the control operation from step 221 to step 230 and sets the pump 1
The operation of Step 4 is stopped, and the process proceeds to Step 231 while the total throttle valve 23 is gradually opened from the minimum opening. If the hot water tap 16 is opened and the pump 14 is stopped, the detected flow rate W is usually 1.5 liter / min or more.
Then, the process proceeds to step S32, in which the hot water supply control is started so that the detected temperature t2 becomes equal to the set value T, and the gradually increased detected flow rate W is limited so as not to exceed 4 liters / min.
Proceed to 3. If the detected temperature t2 of the second temperature sensor 42 is equal to or lower than the tapping temperature set value T, the CPU executes the control operation in step 23.
1 and steps 231 to 233 are repeated, t2> T
If so, the control operation proceeds to step 234 to perform normal control of the total throttle valve 23. As described above, at the start of hot water supply, the total throttle valve 23 gradually opens from the minimum opening degree, and when the detected temperature t2 is equal to or lower than the hot water temperature set value T, the detected flow rate W is reduced.
Since the flow rate is limited so as not to exceed 4 liters / min, even if the hot water tap 16 is suddenly opened, the flow rate of the hot water is slowly increased and the flow rate of the hot water is not excessive. The tapping temperature hardly drops below the tapping temperature set value T even if there is a delay in the heat capacity or heat transfer by the pipe.

The CPU continues the control operation in step 23.
4 to step 241 in FIG. 5, W> 1.5 l / min
That is, if tapping has been performed, steps 241 and 24
2 is repeated to perform hot water supply control and normal control of the total throttle valve 23, whereby hot water is supplied from the hot water tap 16 at the hot water temperature set value T. In this state, as with the first embodiment, the operation of the total throttle valve 23 limits the amount of hot water in spite of the heating ability, or the hot water temperature falls below the hot water temperature set value beyond the heating capacity. Will not be. If the hot water tap 16 is closed to stop tapping, the detected flow rate W
Becomes approximately 0, the CPU stops the combustion of the gas burner 30 in steps 241 to 243,
The control operation returns to step 201. In this case, unless the detected temperature t1 is equal to or lower than T-7, the control operation immediately proceeds from step 201 to step 215, and proceeds to step 21.
After passing through steps 9 and 220, the temperature is maintained at steps 221 to 225. In this case, the possibility of passing through steps 216 to 218 increases, and if the hot water tap 16 is opened from this state, the control operation proceeds from step 217 to step 242 to supply hot water.

Step 235 is step 1 of the first embodiment.
Since it is substantially the same as 35, the description is omitted. Steps 205 and 206 are also substantially the same as steps 105 and 106 of the first embodiment, and a description thereof will be omitted. Hot water tap 1 at the same time or before turning on the power
6, the CPU advances the control operation from step 200 to step 242, similarly to the first embodiment.
Immediately, hot water supply control and normal control of the total throttle valve 23 are performed.

In the second embodiment, the temperature of the hot water near the temperature sensor 42 does not change so much while the hot water is being supplied from the hot water tap 16 and the temperature is maintained, but the heat exchanger 13 is closed immediately after the hot water tap 16 is closed and the gas burner 30 is stopped. The fins and tubes are heated to high temperatures and then cool relatively quickly. If the hot water is discharged after this temperature drop and the gas burner 30 starts burning, the total throttle valve 23 must be opened from the minimum opening degree because of the heat capacity of the fins and tubes of the heat exchanger 13 and the delay of the heat transfer. Drop transiently below the tapping temperature set value T. However, in a state where the fins and tubes of the heat exchanger 13 are heated to a high temperature immediately after the gas burner 30 is stopped, the tapping temperature transiently falls below the tapping temperature set value T without setting the total throttle valve 23 to the minimum opening. Never. Therefore, as in the case of the first embodiment, when the flow rate sensor 45 stops detecting the flow rate and the gas burner 30 stops burning, the timer 47 built in the electronic control unit 40 is started, and the control is performed in steps 216 and 219. The opening degree of the total throttle valve 23 may be set to the opening degree at that time until the timer 47 measures a relatively short predetermined time (for example, one minute), and thereafter may be set to the minimum opening degree. As a result, similarly to the modification of the first embodiment described above, when the tapping stop is frequently repeated in a short time, the tapping flow rate does not decrease each time and the tapping temperature transiently drops below the tapping temperature set value T. Since it does not occur, the usability is improved.

[Brief description of the drawings]

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

FIG. 2 is a part of a flowchart for explaining the operation of the embodiment of FIG. 1;

FIG. 3 is the remaining part of the flowchart for explaining the operation of the embodiment of FIG. 1;

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

FIG. 5 is a part of a flowchart for explaining the operation of the embodiment in FIG. 4;

FIG. 6 is the remaining part of the flowchart for explaining the operation of the embodiment of FIG. 4;

FIG. 7 is an overall configuration diagram of an example of an instant hot water supply apparatus according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Circulation line, 11 ... Outgoing line, 12 ... Return line, 13 ... Heat exchanger, 14 ... Pump, 16 ... Hot water tap, 20 ... Bypass line, 21 ... Automatic mixing valve, 23 ... Total throttle valve, 25 …
Water supply pipe, 30 gas burner, 40 control device (electronic control device), 41, 45, 46 input water detection device (first temperature sensor, flow rate sensor), 42 temperature sensor (second temperature sensor), 47 timer .

Claims (5)

(57) [Claims] 1. A loop comprising an outgoing pipe connecting an inlet side of a heat exchanger heated by a gas burner and a discharge side of a pump, and a return pipe connecting an outlet side of the heat exchanger and a suction side of the pump. -Shaped circulation pipeline, a hot water tap branched off in the middle of the return pipe, a water feed pipe connected halfway in the outgoing pipe, an outlet side of the heat exchanger and a branch position to the hot water tap. In the instant hot water supply apparatus including a temperature sensor provided in the return pipe between the two ends, one end is connected to the connection position of the water supply pipe.
The other end connected to the outgoing pipe between the inlet side of the heat exchanger
Is located between the temperature sensor and the hot-water tap branch position.
A bypass line connected to the pipe;
The total flow through both the heat exchanger and the heat exchanger
The total throttle valve, and the inlet side and front of the water supply pipe
Water inlet detection device installed between the heat exchanger and the inlet side
When the water detection device is detecting the water inflow state, the gas burner is controlled so that the hot water temperature detected by the temperature sensor becomes a predetermined temperature higher by a predetermined value than the set tap water temperature set value. While controlling the gas supply amount, the opening degree of the total throttle valve is set to the minimum opening degree or its vicinity when the water entry detection device does not detect the water entry state,
When the incoming water detection device detects the incoming water state, the controller gradually increases the outlet temperature within a range where the outlet water temperature does not become lower than the outlet temperature setting value, and passes through the temperature sensor provided on the one end side of the bypass pipe. An instant hot water supply apparatus comprising an automatic mixing valve that mixes the high-temperature water at the predetermined temperature and the low-temperature water from the bypass pipe and supplies the mixed water to the hot-water tap side as a temperature of a tap water temperature set value. 2. The control device according to claim 2, wherein the water temperature detected by the temperature sensor is an opening degree of the total throttle valve in a case where the water detection state is not detected by the water detection device and the gas burner stops burning. Until the gas burner stops combustion until the temperature drops to a predetermined temperature higher than the tapping temperature set value by a certain value smaller than the predetermined value, the gas burner maintains the opening at or near the minimum opening. The hot water supply apparatus according to claim 1. 3. The apparatus according to claim 1, further comprising a timer that starts measuring a time when the gas burner stops burning because the water detecting device stops detecting the water inflow condition, and wherein the control device determines whether the water inflow detecting device has detected the water inflow condition. When the detection stops and the gas burner stops burning, the opening degree of the total throttle valve is maintained at the opening degree when the gas burner stops burning until the timer finishes measuring a predetermined time, 2. The instant hot water supply apparatus according to claim 1, wherein the minimum opening degree is set at or near the minimum opening degree after a predetermined time period is measured. 4. A loop constituted by a forward pipe connecting an inlet side of a heat exchanger heated by a gas burner and a discharge side of a pump, and a return pipe connecting an outlet side of the heat exchanger and a suction side of the pump. -Shaped circulation pipeline, a hot water tap branched off in the middle of the return pipe, a water feed pipe connected halfway in the outgoing pipe, an outlet side of the heat exchanger and a branch position to the hot water tap. In the instant hot water supply apparatus provided with a temperature sensor provided in the return pipe, the flow rate of the heat exchanger
A total throttle valve that restricts on the circulation line, a water inlet detection device provided between an inlet side of the water supply pipe and an inlet side of the heat exchanger, and a hot water temperature detected by the temperature sensor are set. The gas supply amount to the gas burner is controlled so as to reach the hot water temperature set value, and the opening degree of the total throttle valve is set at or near the minimum opening degree when the water entry detection device does not detect the water entry state. An instant hot water supply device comprising a control device for gradually increasing the tap water temperature within a range where the tap water temperature does not become equal to or lower than the tap water temperature set value when the tap water detection device detects a tap water state. 5. A timer 47 which starts counting when the gas burner 30 stops burning when the water detecting devices 41, 45, 46 no longer detect a water entering state,
The control device 40 includes the water detection devices 41, 45, 4
6, when the gas burner 30 stops detecting combustion and the gas burner 30 stops burning, the gas burner 30 stops burning until the timer 47 finishes measuring the opening of the total throttle valve 23 and the timer 47 for a predetermined time. 5. The instant hot water supply apparatus according to claim 4, wherein the opening degree is maintained at the time, and after the timing of the predetermined time is completed, the opening degree is set at or near the minimum opening degree.