JP3355044B2 - Water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater, and more particularly to a so-called after-heater in which high-temperature hot water is temporarily discharged from a tapping pipe at the time of restart of hot water supply by post-boiling by a heat exchanger when water supply of the water heater is stopped. The present invention relates to a water heater capable of eliminating a boiling phenomenon and a so-called undershoot phenomenon in which low-temperature hot water is discharged.

[0002]

2. Description of the Related Art Conventionally, as shown in Japanese Utility Model Publication No. 2-39167, for example, a water temperature control valve is provided at a connecting portion between a water supply pipe and a bypass pipe. The drive speed of the throttle shaft of the throttle valve, that is, the time until closing the through hole to the bypass pipe of the temperature control valve is changed according to the hot water supply amount, and the mixing time of the hot water from the tapping pipe and the cold water from the bypass pipe is changed to the hot water supply amount. The tapping temperature was adjusted by changing the temperature accordingly. That is, when the amount of hot water is large, the time until the hole of the temperature control valve to the bypass pipe is closed is shortened, and when the amount of hot water is small, the time until the hole of the temperature control valve is closed is lengthened.

[0003]

However, in the above-mentioned water heater, mixing of hot water and water is not always performed uniformly, and there is a possibility that the temperature of the hot water may become uneven. In other words, since the temperature distribution of the hot water staying in the appliance immediately before the start of hot water supply is uneven, even if cold water is mixed from the bypass pipe at the start of hot water supply,
Actually, the temperature of the hot water fluctuates greatly, causing overshoot and undershoot. Generally, tapping temperature control such as adjusting tapping amount by detecting tapping temperature is used. However, such control cannot cope with uneven temperature distribution of tap water. An object of the present invention is to solve the above-described problem, and an object of the present invention is to provide a water heater that can reduce an overshoot phenomenon and an undershoot phenomenon at the time of restarting hot water supply.

[0004]

In order to achieve the above object, the structural features of the invention according to claim 1 include a burner for heating a heat exchanger, a water supply pipe for guiding water to the heat exchanger, A tapping pipe that sends out the hot water exchanged in the heat exchanger to the outside,
In a water heater provided with a blower for supplying combustion air to a burner, a closed loop connecting a bypass pipe and a heat exchanger is provided, while a bypass pipe is provided to bypass a heat exchanger and communicate between a water supply pipe and a tapping pipe. It is provided with a blade disposed in a pipeline and rotatably supported by a shaft, and a connecting means for transmitting the rotational driving force of the blower to the rotary shaft of the blade when hot water supply is stopped.

[0005] Further, a structural feature of the invention according to claim 2 is that, in the water heater according to claim 1, the connecting means operates in synchronization with post-purge by the blower at the end of hot water supply. It is in.

A third aspect of the present invention is a water heater according to the first or second aspect, wherein the temperature of the hot water forcedly circulated by the rotation of the blades when the hot water supply operation is stopped. The control means for controlling so that the heating by the burner is restarted when the temperature becomes equal to or lower than a certain temperature is provided.

[0007]

According to the first aspect of the present invention, after the heating of the heat exchanger by the burner due to the stop of the hot water supply operation of the water heater is completed, the exhaust gas in the combustion chamber is blown by the blower. Post-purging is performed to discharge the gas out of the apparatus. At this time, the rotational driving force of the blower is transmitted to the rotating shaft of the blade by the connecting means, and the blade starts to rotate, and water is introduced into a closed loop pipe including a water supply pipe, a tapping pipe, a bypass pipe, and a heat exchanger. Can be circulated. This allows
The cold water in the water supply pipe and the bypass pipe, the hot water in the tapping pipe, and the hot water generated by the post-boiling in the heat exchanger are mixed and mixed, and while the water is circulating, the hot water exchanges heat with the circulation pipe and becomes uniform. Temperature.

As a result, the temperature of the hot water staying in the appliance is averaged, and the overshoot and undershoot of the hot water temperature at the start of the next hot water supply are reduced. According to the first aspect of the present invention, since the rotation of the blade can be performed by using the rotation of the blower, it is not necessary to newly provide a rotating device, and the above-described effects can be obtained simply and inexpensively. Can be.

Further, according to the second aspect of the present invention, since the blades rotate in synchronization with the post-purge by the blower, it is necessary to newly provide a control device for controlling the rotation of the blades. In addition, the above-described effect can be obtained without changing the control part of the water heater, which is convenient.

[0010] Further, by arranging the invention according to the third aspect as described above, the circulating hot water having a temperature equal to or lower than a certain temperature can be made into uniform hot water having a certain temperature or higher by reheating with a burner. As a result, the rise of the tapping temperature can be accelerated.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a water heater according to the embodiment. The water heater is provided with a water supply pipe P1 connected to a water supply source (not shown) such as a water supply.
Is connected to one end of a heat exchanger 10 having fins around it. The other end of the heat exchanger 10 is connected to a tapping pipe P2.
Is connected to one end. Then, as shown in FIG. 1, the water supply pipe P1 and the tapping pipe P2 are guided downward through a cylindrical body (hereinafter referred to as an inner body) 20, which will be described later. Hot water pipe P2
Is connected to an external pipe leading to a hot water tap 12 provided in a washroom, a kitchen or the like. The tapping pipe P2 is connected to the heat exchanger 1
A thermistor 11 for measuring hot water temperature is provided at a position slightly away from zero. Between the water supply pipe P1 and the hot water pipe P2,
A bypass pipe PB for bypassing both is provided branching off from both. The bypass pipe PB has a bent shape which is bent at right angles in opposite directions at two places, and the tip of the high horizontal part PB1 is attached to the water supply pipe P1 with the middle part PB2 facing up and down. The tip of the section PB3 is attached to the tapping pipe P2. And the water pipe P1
A water flow sensor 13 is provided slightly upstream of the branch position of the bypass pipe PB.

The heat exchanger 10 is surrounded by an inner body 20 forming a combustion chamber R therein, and a gas nozzle 21a is mounted on the bottom right side of the inner body 20. Gas nozzle 21
a is connected to a gas supply pipe PG provided with a proportional control valve 22a for gas amount adjustment and an electromagnetic valve 22b for opening and closing a gas flow path, and sends gas from a gas supply source (not shown) to the burner 21b. Supply. The burner 21b is ignited by the ignition of the igniter 23 in the gas supply state, and the heat exchanger 10 is heated by the combustion of the gas. Further, the combustion exhaust gas is discharged to the outside by an exhaust hood 27 provided above the heat exchanger 10.

The inner body 20 is provided with a blower 24 for supplying combustion air into the combustion chamber R from the bottom. Blower 2
4 is a sirocco fan (hereinafter, referred to as a fan) in the fan case 20a.
A fan 24a is rotatably supported, and an electric motor 24c is connected to one end of a rotating shaft 24b. The other end of the rotating shaft 24b penetrates through the fan case 20a and is attached to a fixed plate 25b of an electromagnetic clutch 25 which is a torque transmission control device.

The electromagnetic clutch 25 is, as shown in FIG.
A box-shaped housing 25a is provided.
A fixed plate 25b is provided on one side in the area a. Fixing plate 25
An electromagnetic solenoid 25c is attached to b. A movable plate 25d is provided on the opposite side of the fixed plate 25b. The movable plate 25d is urged by a coil spring 25e attached to the wall of the housing 25a and is pulled rightward, and usually has a gap between the movable plate 25d and the fixed plate 25b. The movable plate 25d is provided with an electromagnetic solenoid 25c.
, And is fixed to the fixed plate 25b in close contact. Then, the rotating shaft 2 is provided on the movable plate 25d.
6a, the other end of the rotating shaft 26a extends through the right side wall of the housing 25a, extends through the upper end wall of the intermediate portion PB2 of the bypass pipe PB, and extends into the high horizontal portion PB1. Is provided with a blade 26b.

Next, an electric control device 30 for electrically controlling the operation of the water heater configured as described above will be described with reference to the drawings. This electric control device 30 is the same as that shown in FIG.
As shown in the figure, a control circuit 31 is provided. Control circuit 3
1 includes a microcomputer including a CPU, a ROM, a RAM, a timer, an I / O, and the like.
"Hot water supply control program" corresponding to the flowchart shown in FIG. The thermistor 11 and the water flow sensor 13 are connected to the input side of the control circuit 31. On the output side of the control circuit 31, a proportional control valve 22a, an electromagnetic valve 22b, an igniter 23, an electric motor 24c for driving a fan 24a, and an electromagnetic solenoid 25c of an electromagnetic clutch 25 are connected via drive circuits 32a to 32e. ing. The drive circuits 32a to 32e receive signals from the control circuit 31 and control energization to the proportional control valve 22a, the electromagnetic valve 22b, the igniter 23, the electric motor 24c for the fan, and the electromagnetic solenoid 25c for the electromagnetic clutch.

Next, the operation of the embodiment configured as described above will be described. When a power switch (not shown) is turned on, the control circuit 31 starts executing a “hot water supply control program” shown in FIG.
At step 1, various variables are initialized. Next, at step 42, the presence or absence of water passage is determined. When water is passed through the appliance by opening the hot water tap 12, the water flow sensor 13 is turned on. In response to this, the control circuit 31 shifts the program to step 43 based on the determination of “YES” in step 42, turns on the solenoid valve 22b and sends the gas to the burner 21.
b, and the igniter 23 is operated to ignite the gas and start the combustion control. At the same time, the electric motor 24
c, the fan 24a is rotated to supply combustion air to the upper portion of the combustion chamber R.

Then, at step 44, it is determined whether or not the water is stopped. When the water supply is stopped by closing the hot water tap 12 and the water flow sensor 13 is turned off, “YE
Based on the determination of "S", the program proceeds to step 45, and the combustion control ends. Further, at step 46, a timer built in the control circuit 31 causes a predetermined time t.
A zero count is started. Next, in step 47, the control circuit 31 outputs a post-purge start signal. In response to this, the drive circuit 32d causes the electric motor 24c to rotate at a lower rotational speed than the rotational speed during the combustion control, and causes the blower 24 to start the post-purge. Next, at step 48, the control circuit 31 controls the electromagnetic solenoid 25.
c is output, and the driving circuit 32e
Turns on the electromagnetic solenoid 25c to attract and fix the movable plate 25d to the fixed plate 25b. Thereby, the rotating shaft 2
6a starts rotating in accordance with the rotation of the blower 24, and the blade 2
6b is rotated to supply water in the bypass pipe PB to the water supply pipes P1,
Circulate through heat exchanger 10 and tapping pipe P2, bypass pipe PB
Then, the hot water in the closed loop pipe composed of the water supply pipe P1, the tapping pipe P2 and the heat exchanger 10 is stirred.

Then, at step 49, the water flow sensor 1
It is determined whether or not 3 is turned on, that is, whether or not the hot water tap 12 is opened and the water is passed while the combustion is stopped. If water supply has not been restarted, the program proceeds to step 50 based on the determination of "NO" in step 49, and it is determined whether or not the timer has finished measuring a certain time. If the counting has not been completed, the program returns to step 49 based on the determination of "NO", and continues to monitor whether or not the water flow sensor 13 has been turned on during the timer counting. When the counting of the predetermined time is completed, the program proceeds to step 51 based on the determination of “YES” in step 50, and the control circuit 31 outputs the electric motor stop signal, and accordingly, the drive circuit 32d Stops the rotation of the electric motor 24c and ends the post-purge. Further, in step 52, an OFF signal of the electromagnetic solenoid 25c is output, and in response to this, the drive circuit 32e stops energizing the electromagnetic solenoid 25c and isolates the movable plate 25d from the fixed plate 25b. Thereby, the rotation of the blade 26b is also stopped, and the circulation of the hot water in the closed loop pipe is also stopped. Then, the program returns to step 42, and the resumption of water flow is awaited. During the above operation, while the blade 26b is rotating, the hot water
2 is opened and the flow of water is resumed, the water flow sensor 13 is turned on, and accordingly "YES" in step 49.
The program is moved to step 53 based on the determination that
The energization of the electromagnetic solenoid 25c is stopped, and the rotation of the blade 26b is stopped. In addition, the program proceeds to step 43
And the above-described combustion control is started.

As described above, according to the present embodiment, the rotary shaft 26a is connected to the rotary shaft 24b of the electric motor 24c simultaneously with the post-purge by the blower after the hot water supply operation of the water heater is stopped. Then, the blade 26b attached to the other end of the rotating shaft 26a starts rotating, and circulates water in a closed loop pipe including the water supply pipe P1, the tapping pipe P2, the heat exchanger 10, and the bypass pipe PB. it can.
As a result, the cold water in the water supply pipe P1 and the bypass pipe PB, the hot water in the tapping pipe P2, and the high-temperature hot water due to the post-boiling in the heat exchanger 10 are agitated and mixed to make hot water of a uniform temperature.

Therefore, the temperature of the hot water staying in the appliance is averaged, and the overshoot and undershoot of the hot water temperature at the start of the next hot water supply are reduced. In particular, when controlling the gas amount by detecting the tapping temperature, the non-uniformity of the tapping temperature distribution in the appliance greatly affects the tapping temperature, but the tapping temperature is hunted. By doing so, it becomes easy to control the hot water temperature. Further, in the present embodiment, since the rotation of the blade 26b can be performed by using the rotation of the blower 24, it is not necessary to newly provide a rotating device, and the above-described effect can be obtained simply and inexpensively. .
Further, by synchronizing the rotation of the blade 26b with the rotation of the blower, it is not necessary to newly provide a control device for controlling the rotation of the blade 26b, so that the above effect can be obtained without changing the control part. And convenient.

Next, a first modification of the first embodiment will be described with reference to FIG. In the first modification, the blade 2
By stirring the hot water in the closed loop pipe by 6b, when the hot water temperature falls below a certain value, the hot water is heated by the combustion gas until the hot water temperature reaches a certain value or more, or heated for a certain period of time. The temperature is intended to be higher than a certain value. The thermistor 11 is used for temperature detection.
In addition, in the first modification, as shown in FIG. 5, whether the hot water temperature is equal to or higher than the constant temperature TL, between steps 48 and 49 or between steps 49 and 50 in the flowchart shown in FIG. And a step 48b indicating a warm combustion routine.

In the first modification configured as described above, when the temperature T of the hot water becomes equal to or lower than the predetermined value TL due to stirring during the rotation of the blade 26b, "N" is set in step 48a.
Based on the determination of "0", the process proceeds to step 48b, in which the heating is performed by the combustion gas for a predetermined time or until the temperature becomes equal to or higher than a predetermined temperature. This allows
It is possible to prevent the temperature of the hot water after the start of hot water supply from dropping from the fixed reference value TL, and the object of the present invention can be realized more accurately.

In the above embodiment, the blades 26b
Is provided in the bypass pipe PB, but as a modified example, it may be provided in the water supply pipe P1 as shown in FIG. 6, or may be provided in the tapping pipe P2 (not shown). Further, the configuration of the electromagnetic clutch is not limited to that shown in the embodiment. Further, as the torque transmission control device,
The present invention is not limited to the above-mentioned electromagnetic clutch, but may be one using an air cylinder or the like. The arrangement of the various components of the water heater shown in each of the above embodiments is merely an example, and can be changed as appropriate according to the purpose and application of the water heater.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a water heater according to one embodiment of the present invention.

FIG. 2 is a partially broken sectional view schematically showing a connecting device for connecting a fan and a blade of a blower of the water heater.

FIG. 3 is a block diagram showing an electric control device of the water heater.

FIG. 4 is a flowchart of a “hot water supply control program” executed by the control circuit of FIG. 3;

FIG. 5 is a diagram showing a part of a flowchart as a changed part of the “hot water supply control program” according to the first modification.

FIG. 6 is a front view schematically showing a modification of the water heater.

[Explanation of symbols]

10 heat exchanger, 11 thermistor, 12 hot water tap, 1
3: water flow sensor, 20: inner body, 21a: gas nozzle, 2
1b: burner, 22a: proportional control valve, 22b: solenoid valve,
23 ... igniter, 24 ... blower, 24a ... fan, 2
4b: rotating shaft, 24c: electric motor, 25: electromagnetic clutch, 25a: housing, 25b: fixed plate, 25c: electromagnetic solenoid, 25d: movable plate, 26a: rotating shaft, 26
b: blade, 30: electric control unit, 31: control circuit, P1
... water supply pipe, P2 ... tapping pipe, PB ... bypass pipe, PG ... gas supply pipe.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-350457 (JP, A) JP-A-1-51152 (JP, U) JP-A-3-13061 (JP, U) JP-A-62-1 12412 (JP, U) Shokai Sho 57-188046 (JP, U) Jiko 2-39167 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24H 1/10 302

Claims (3)

(57) [Claims] 1. A burner that heats a heat exchanger, a water supply pipe that guides water to the heat exchanger, a tapping pipe that sends out hot water that has been heat-exchanged in the heat exchanger, and a burner for burning. In a water heater provided with a blower for supplying air, a closed pipe that connects the bypass pipe and the heat exchanger while providing a bypass pipe that bypasses the heat exchanger and connects the water supply pipe and the tapping pipe. A water heater comprising: a blade disposed in a path and rotatably supported by a shaft; and a connecting means for transmitting a rotation driving force of the blower to a rotation shaft of the blade when hot water supply is stopped. 2. The water heater according to claim 1, wherein the connecting means operates in synchronization with post-purge by the blower at the end of hot water supply. 3. The water heater according to claim 1 or 2, wherein when the temperature of the hot water circulated forcibly by the rotation of the blades at the time of stopping the hot water supply operation becomes lower than a certain temperature, the burner is used. A water heater characterized by comprising control means for controlling heating to resume.