JPH10267409A - Combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a temperature of effluent hot water in a combustion apparatus in which there is provided a bypass pipe for guiding water flowing through a water inlet pipe to an effluent hot water pipe by closing the bypass valve after the lapse of a first time after hot water is again effused when the bypass valve is opened upon the hot water is again effused, and opening the bypass valve after the lapse of a second time. SOLUTION: A combustion apparatus 1 mixes high temperature to water from a heat exchanger 2 and water flowing through a bypass pipe 11 and effuses hot water at about 40 degree. Herein, when the effluent hot water is once interrupted, a hot water effluent cock is again opened to ignite a burner 4, and thereupon the time till restart of hot water is shorter than the time since pervious combustion, the inside of the heat exchanger 2 is high temperature owing to laser heating so that a bypass solenoid valve 12 is opened and cold water from the bypass pipe 11 is formed to flow in. Then, in order to suppresses undershooting produced after overshooting, the bypass solenoid valve 12 is closed at time T1. After the lapse of certain time t2 after the undershooting is converged, the bypass solenoid valve 12 is again opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus provided with a bypass pipe, and more particularly to a stabilization control of a tapping temperature at the time of re-starting tapping in such a combustion apparatus.

[0002]

2. Description of the Related Art FIG. 5 shows a configuration diagram of a general water heater 1 having a bypass passage. According to FIG. 5, an inlet pipe 3 for supplying water to the heat exchanger 2 is connected to the inlet side of the heat exchanger 2. The water supplied to the heat exchanger 2 performs heat exchange therein, and flows out through a tapping pipe 5 connected to the outlet side of the heat exchanger 2. Gas is supplied to the burner 4 from a gas supply pipe 6, and the gas amount can be adjusted by a gas proportional valve 7. In addition, the inlet pipe 3 is provided with a flow rate sensor 8 for detecting the amount of incoming water and an incoming water temperature sensor 9 for detecting the incoming water temperature, and the outlet pipe 5 is provided with an outlet temperature sensor 10 for detecting the outlet temperature. .

Further, the water heater 1 is provided with a bypass pipe 11 for sending water flowing through the water inlet pipe 3 to the tap water pipe 5 without passing through the heat exchanger 2.
The bypass pipe 11 includes a bypass solenoid valve 12 for opening and closing the flow path.

[0004] The water heater 1 is usually provided with a remote control 14.
FF (feed forward) control based on the set temperature Ts set in the above, the incoming water temperature Ti detected by the incoming water temperature sensor 9 and the incoming water flow rate Vi detected by the flow rate sensor 8, and the set temperature Ts and the outgoing water temperature sensor 10 Based on the detected tap water temperature To and the incoming water flow rate Vi, the tap water temperature T is controlled by FB (feedback) control.
so that o is maintained at the set temperature Ts.
The opening of the gas proportional valve 7 and the opening and closing of the bypass solenoid valve 12 are adjusted so that hot water at the set temperature Ts is discharged.

[0005]

FIG. 6 shows a timing chart of the conventional combustion control at the time of hot water re-discharge in such a water heater 1. According to FIG. 6, after the end of combustion, at time t0
When the tap is opened again, the combustion is restarted. The tapping temperature at this time indicates a change in a so-called overshoot state in which high-temperature hot water is discharged from the heat exchanger 2 due to so-called post-boiling of the heat exchanger 2 immediately after the tapping again (A
Department).

Further, at the time of re-water supply, there is a slight time lag from when the tap is opened to when gas is supplied to the burner, combustion starts, and the temperature of the water from the heat exchanger 2 starts to rise. . For this reason, even after hot water having been subjected to post-boiling in the heat exchanger 2 and hot water that has not yet been sufficiently heat-exchanged from the heat exchanger 2, cold water flows in from the bypass pipe 11. An undershoot state occurs in which water at a temperature lower than Ts is temporarily discharged (part B).

[0007] In such hot water supply characteristics, conventionally, the bypass solenoid valve 12 is opened simultaneously with the re-water supply and the bypass pipe 1 is opened.
By mixing with water from No. 1, overshoot of tapping temperature To was suppressed as shown by dotted line portion C in the figure, but the above-mentioned undershoot cannot be avoided.

When the bypass solenoid valve 12 is opened when no overshoot occurs, the bypass pipe 11
Chilled water flows in from below, and enters an undershoot state.

Accordingly, an object of the present invention is to provide a combustion apparatus which suppresses the occurrence of undershoot at the time of re-watering and stabilizes the temperature of the hot water.

[0010]

According to a first aspect of the present invention, there is provided a bypass pipe for guiding water flowing through an inlet pipe to a hot water pipe without passing through a heat exchanger, In a combustion device provided with a bypass valve for opening and closing a pipe, when the bypass valve is opened at the time of refilling, after a lapse of a first time from the time of refilling, the bypass valve is closed, and further, the first time This is achieved by providing a combustion device wherein the bypass valve is opened after a longer second time has elapsed.

Further, according to a second aspect of the present invention, there is provided a bypass pipe for guiding water flowing through an inlet pipe to a hot water pipe without passing through a heat exchanger, and a bypass for opening and closing the bypass pipe. In a combustion device provided with a valve, when the temperature at which hot water is discharged from the heat exchanger at the time of re-hot water is equal to or higher than a set temperature, the bypass valve is opened, and after a lapse of a first time from the time of re-hot water, the bypass is opened. The valve is closed, and further, after a lapse of a second time longer than the first time, the bypass valve is opened, and when the temperature of tapping water from the heat exchanger is lower than the set temperature, the second valve is closed. This is achieved by providing a combustion device wherein the bypass valve is opened after a lapse of time.

Thus, the overshoot state occurring at the time of hot water re-supply is suppressed by opening the bypass valve and allowing the cold water to flow from the bypass pipe 11, and when the undershoot state occurs, the bypass valve is closed. It can be suppressed. Furthermore, when overshoot does not occur, control is performed so as not to open the bypass valve, so that undershoot due to opening the bypass valve can be prevented.

The first time is a time when the temperature of the hot water from the hot water pipe enters an undershoot state, and the second time is a time when the temperature of the hot water from the hot water pipe reaches the set temperature. It is preferable that the time is a time after the time reached.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to this embodiment. The combustion device according to the present embodiment has substantially the same configuration as the combustion device described in FIG.
The same or similar elements as those described above are denoted by the same reference numerals or reference symbols, and description thereof is omitted.

FIG. 1 shows a combustion apparatus 1 according to this embodiment.
3 is a control function block diagram of a control unit 13 of FIG. These functions are realized by software when the control unit 13 is realized by a microcomputer. The control unit 13 shown in FIG. 1 is provided in the flow rate sensor 8 and the heat exchanger 2 and receives an input signal from a heat exchanger temperature sensor (hereinafter referred to as a heat exchange temperature sensor) 15 for detecting the temperature inside the heat exchanger 2. The bypass solenoid valve 12 is controlled based on the control. The configuration includes a bypass solenoid valve opening / closing determination unit 131 that determines whether the temperature in the heat exchanger 2 at the time of re-hot water detected by the heat exchange temperature sensor 15 is equal to or higher than the opening / closing determination temperature Tn, It comprises a driving unit 134, a timer unit 133 for measuring time from the time of re-hot water supply, and a t1 calculation unit 132 for obtaining a predetermined time t1 (described later) measured by the timer unit 133.

A description will now be given of the combustion control by the control unit 13 at the time of re-starting hot water in the present invention. FIG. 2 is a flowchart of the combustion control in the present invention. In FIG. 2, when the flow sensor 8 is turned on (Step S)
1) Gas is supplied to the burner 4 and ignited (step S2), and the bypass solenoid valve 12 is opened (step S3).

Usually, the hot water supply temperature used by the hot water supply user is 4
It is often around 0 degrees. However, when hot water having a relatively low tapping temperature such as about 40 degrees is discharged from the heat exchanger 2,
The inside of the heat exchanger 2 may be condensed and thereby corroded. Therefore, even if the tapping temperature is relatively low,
The temperature of tap water from the heat exchanger 2 is set to a predetermined temperature (for example, 60 degrees).
In order to maintain the above, the bypass solenoid valve 12 is opened, hot water of a predetermined temperature or higher from the heat exchanger 2 and the bypass pipe 11
The water flowing through is mixed, and hot water of about 40 degrees is discharged. Therefore, in the present embodiment, during combustion, combustion is performed with the bypass solenoid valve 12 opened.

In step S4, the flow sensor 8
In the FF state, the gas supply is stopped and the combustion is stopped (Step S5), and the bypass solenoid valve 12 is closed (Step S6).

Thereafter, when the tap is opened again, the flow sensor 8 is turned on (step S).
7) The burner 4 is ignited again (step S)
8).

At this time, the bypass solenoid valve opening / closing determination section 13
The following control is performed according to the temperature inside the heat exchanger 2 input to 1. For example, when the time until the re-hot water is short from the previous combustion, the inside of the heat exchanger 2 is at a high temperature due to post-boiling. Therefore, when the temperature detected by the heat exchange temperature sensor 15 is equal to or higher than the predetermined temperature Tn at which overshooting is caused by the subsequent boiling (step S9),
In order to suppress this, the bypass solenoid valve 12 is opened (step S10), and cold water flows from the bypass pipe 11.

Next, in order to suppress an undershoot occurring after the overshoot, the bypass solenoid valve 12 is closed at time t1. Thereby, the bypass pipe 11
Inflow of cold water from the tank stops, and undershoot is suppressed.

The time t1 is a time at which an undershoot occurs from the time of re-discharging, and can be obtained by calculation or experiment. FIG. 4 is a diagram showing the relationship between the amount of post-boiling and the time during which undershoot occurs. According to FIG. 4, the time t1 from the time of re-discharging is a time that varies depending on the amount of post-boiling.
0 to later time. The amount of boiling after this can be estimated from the temperature in the heat exchanger 2, the time from the previous combustion to the second hot water, and the like. In the present embodiment, FIG.
Is calculated from the temperature in the heat exchanger 2 to obtain a time t1. The obtained time t1 is input to the timer unit 133, and the timer unit 133 sends a bypass solenoid valve closing signal to the bypass solenoid valve driving unit 134 when the time t1 has elapsed, and the bypass solenoid valve 12 is closed.

Returning to FIG. 2, a predetermined time t1 from the time of re-starting hot water
Has elapsed (step S11), the bypass solenoid valve 12 is closed as described above (step S12). Finally, since it is preferable that combustion be performed with the bypass solenoid valve 12 opened, after a lapse of time t2 after the undershoot has converged (step S13),
Again, the bypass solenoid valve 12 is opened (step S
3).

The time t2 is a time determined in advance from an experiment or the like, and is measured by the timer unit 133. Then, when the time t2 elapses from the time of re-hot water supply, a bypass solenoid valve opening signal is sent from the timer unit 133, and the bypass solenoid valve driving unit 134 closes the bypass solenoid valve 12.

On the other hand, in step S9, the heat exchanger 2
If the inside temperature is lower than the predetermined temperature Tn, for example, since the after-boil has cooled because a considerable time has elapsed since the previous combustion, if the bypass solenoid valve 12 is opened at the same time as the hot water is re-discharged, Since the amount of cold water flowing into the tapping pipe 5 increases, an undershoot occurs. Therefore, in such a case, control is performed so that the bypass solenoid valve 12 is not opened. As a result, the bypass solenoid valve 12 is
Can be prevented from undershooting due to opening.

FIG. 3 is a timing chart of opening / closing of the bypass solenoid valve 12 based on the above flow and the temperature of the tap water. According to FIG. 3A, when the heat exchange temperature at the time t0 at the time of re-hot water is equal to or higher than the predetermined temperature Tn, the bypass solenoid valve 12 is opened at the time t0. Thereby, the overshoot due to the post-boiling indicated by the dotted line A can be suppressed. Thereafter, the bypass solenoid valve 12 is opened, and the bypass solenoid valve 12 is closed at a time t1 at which an undershoot occurs due to the inflow of cold water from the bypass pipe 11. Therefore, since cold water does not flow from the bypass pipe 11, the undershoot indicated by the dotted line B is suppressed. Further, in order to perform combustion with the bypass solenoid valve 12 opened, the bypass solenoid valve 12 is opened after a lapse of a predetermined time t2 when the tapping temperature is stabilized.

FIG. 3 (b) shows the time t0 at the time of re-discharge.
Is less than the predetermined temperature Tn, the bypass solenoid valve 12 remains closed at time t0. In this case, the post-boiling in the heat exchanger 2 has not occurred or has already disappeared when the hot water is re-discharged, and the bypass solenoid valve 12 cannot be opened because it is not in an overshoot state. Further, even when an undershoot state (dotted line B) occurs due to the conventional bypass solenoid valve 12 being opened, the bypass solenoid valve 12 is closed, the tapping water temperature rises, and after a lapse of a predetermined time t2 when it stabilizes. The bypass solenoid valve 12 is opened.

In the present embodiment, whether or not an overshoot has occurred at the time of re-hot water is determined based on the temperature in the heat exchanger 2 as described above. However, the present invention is not limited to this. It is also possible to determine the presence or absence of the overshoot based on the length of time from the end to the time of re-hot water, the amount of combustion in the previous combustion, or an amount in consideration of a plurality thereof.

Further, the heat exchanger temperature sensor 15 is not located inside the heat exchanger 2 but near the exit of the heat exchanger 2 (for example, point P).
May be provided.

[0030]

As described above, according to the present invention,
At the time of re-hot water, when the overshoot occurs, the bypass solenoid valve is opened, and when the undershoot occurs, the bypass solenoid valve is controlled to be closed. Hot water with a stable tapping temperature can be supplied.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control unit of a combustion device according to the present invention.

FIG. 2 is a flowchart of combustion control according to the present invention.

FIG. 3 is a timing chart of combustion control in the embodiment of the present invention.

FIG. 4 is a diagram showing the relationship between the amount of after-boiling and the time during which undershoot occurs.

FIG. 5 is a schematic configuration diagram of a combustion device.

FIG. 6 is a timing chart of a conventional combustion control.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 hot water supply unit 2 heat exchanger 3 water inlet pipe 4 burner 5 tapping pipe 6 gas supply pipe 7 gas proportional valve 8 flow sensor 9 incoming water temperature sensor 10 tapping water temperature sensor 11 bypass pipe 12 bypass solenoid valve 13 control unit 14 remote control 15 heat exchanger Temperature sensor

Claims (3)

[Claims] 1. A combustion apparatus having a bypass pipe for guiding water flowing through a water inlet pipe to a hot water pipe without passing through a heat exchanger, and a bypass valve for opening and closing the bypass pipe. When the first time has elapsed since the second hot water supply, the bypass valve is closed, and further, after a second time longer than the first time has elapsed, the bypass valve is opened. . 2. A combustion apparatus comprising: a bypass pipe for guiding water flowing through an inlet pipe to a hot water pipe without passing through a heat exchanger; and a bypass valve for opening and closing the bypass pipe. When the temperature at which the hot water is discharged is equal to or higher than the set temperature, the bypass valve is opened, and after a lapse of a first time from the time of re-hot water, the bypass valve is closed,
Further, after a lapse of a second time longer than the first time, the bypass valve is opened, and when the temperature of tapping water from the heat exchanger is lower than the set temperature, after the lapse of the second time, The combustion device wherein the bypass valve is opened. 3. The method according to claim 1, wherein the first time is a time when the temperature of the hot water from the tapping pipe is in an undershoot state, and the second time is a time when the temperature of the tapping water is from the tapping pipe. A time period after the temperature of the hot water reaches the set temperature.