JP2000111159A - Hot water supplier provided with heat insulating function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To see that the hot water supplier does not perform a supply of excessive quantity of heat by controlling the heat insulating combustion time accurately. SOLUTION: When heat insulation control starts and a proportional control valve is turned on, the second timer starts first. The second timer is set within a time which does not exceed the combustion upper limit time Tmax where heat insulating time T3 is added to the time T1 from ON of the proportional control valve to the flame detection by a flame rod 16a and the time from the opening of the main solenoid valve 13c to the flame detection by a flame rod 16b. Moreover, when the burner combusts at large and the detection of the flame by the flame rod 16b is done, the first timer at the heat insulating time T3 starts in parallel, and when either the first time or the second timer times up, the combustion of a burner is stopped even if it is in counting of the other hand.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater with a heat retaining function that can burn a burner in a water stop state for a predetermined heat retaining time and maintain the water temperature in the appliance within a predetermined temperature range.

[0002]

2. Description of the Related Art At the start of use of a water heater, first, water stored in the appliance is sent out, and it takes time to rise the tap water temperature. Therefore, the burner is heated to a predetermined temperature without using the water heater. Combustion in quantity, water temperature in the appliance is maintained in a predetermined temperature range, and when using a water heater, a warming function is provided to obtain hot water at the set temperature with a quick rise and improve usability. It has been known. Specifically, FIG.
As shown in (1), when the heat retention control starts, a control valve (solenoid valve) for controlling the supply of the fuel gas to the burner is opened at t ₁ to supply the fuel gas to the burner, and at the same time, the igniter is turned on to turn on the burner. Is ignited. Then t ₂
In flame rod detects a flame, the count of the incubation time by the timer means T ₁ is initiated by the flame detection. Then, by the time-up with t _3, the solenoid valve is closed, the combustion of the burner is stopped. These operations are intermittently repeated when the water temperature in the appliance decreases due to heat radiation.

[0003]

However, due to the deterioration of the flame rod over time, the flame detection timing t ₂ by the flame rod is later than the timing (t ₂ ′) at which the flame actually appears upon ignition of the burner. May be. In this case, the actual heating and burning time T by the burner is equal to the heat retention time T ₁ + the detection delay time T ₂ , which is longer than the set heat retention time T ₁ . As a result, an excessive amount of heat is supplied to the inner body, which may cause boiling and deterioration of the inner body.

In view of the above, the first aspect of the present invention is to precisely control the combustion time of the burner accompanying the heat retention control so as not to supply an excessive amount of heat to the inner body and to prevent the occurrence of boiling or deterioration of the inner body. It is intended to provide a water heater with a function.

[0005]

In order to achieve the above object, the invention according to claim 1 starts with opening of the control valve upon ignition of the burner, and at least waits for the warming time by the timer means. A second timer means is provided which sets a combustion upper limit time including a rise time from the ignition of the burner to the flame detection by the flame detection means, and the earlier time-up of the timer means and the second timer means is provided. And the combustion of the burner is stopped.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a water heater with a heat retention function (hereinafter abbreviated as “water heater”), in which a water heater 1 is connected to a water supply pipe 3 connected to an inner body 2 forming a combustion chamber therein. A heat exchanger 5 for heating water with the combustion heat of the burner 4 is provided.
Is connected. The water supply pipe 3 is provided with an incoming water temperature sensor 7 for detecting the temperature of the water passing through the water supply pipe 3 and a water quantity sensor 8 for detecting the flow rate of the water. The tap water temperature sensor 9 for detecting the temperature is connected to the heat exchanger 5
The inner body temperature sensors 9a for detecting the temperature of the water in the heat exchanger 5 are provided between the endothermic pipes in FIG. Burner 4
A main solenoid valve 11, a proportional control valve 12, and main solenoid valves 13a to 13c are respectively provided from the upstream side in the gas flow path to the gas passage, and these valves are also opened and closed by the controller 10, but the burner here. 4 is branched into four, seven, and six burner groups 4a to 4c, and main solenoid valves 13a to 13c are provided for each branch flow path, and combustion by each burner group alone or in combination is possible. It has a form. And between and near the burner groups 4a to 4c,
The igniter 14 operated under the control of the controller 10
Electrode 15, burner groups 4a and 4b, and burner group 4c
Frame rods 16a and 16b as flame detecting means for detecting a flame of
Are provided respectively. Further, the controller 10 is connected to a remote controller 17 including an operation switch, a button for adjusting a set temperature, a heat insulation switch 18 for heat insulation control, and the like.

Therefore, in the water heater 1, when the water flow sensor 8 detects the water flow through the appliance by opening a faucet (not shown) connected to the tapping pipe 6, the controller 10 returns to the original solenoid valve. 11 and main solenoid valves 13a to 13c
Are opened, the igniter 14 is operated to continuously spark the ignition electrode 15, and the proportional control valve 12 is opened to ignite the burner 4. Thereafter, the controller 10 calculates the required heating amount from the initial water temperature obtained from the incoming water temperature sensor 7 so that the hot water is supplied at the set temperature set by the adjustment button of the remote controller 17, and the opening degree of the proportional control valve 12. Is adjusted, and the opening of the proportional control valve 12 is corrected and controlled based on the detected temperature obtained from the tapping temperature sensor 9 so that the tapping temperature matches the set temperature.

Then, the controller 10 controls the remote controller 1
7 is turned on, the burner 4 is burned in a water-stopped state, heating is performed while water is stored in the appliance, and the detected temperature obtained from the inner body temperature sensor 9a is monitored. Then, a heat retention control for keeping the water in the appliance at a constant temperature is executed. Hereinafter, this heat retention control will be described with reference to the flowchart of FIG. 2 and the time chart of FIG. In S1, the heat retention switch 18 is turned on, and in S2, when it is confirmed that the appliance water temperature obtained by the inner body temperature sensor 9a has decreased to a predetermined temperature or lower, the original solenoid valve 11 is opened in S3. At the same time, the igniter 14 operates (t ₁ ),
The main electromagnetic valve 13a in S4, 13b are respectively open (t _2). Then, the proportional control valve 12 is ON with burner group 4a and 4b is burning at S5, wherein the second timer as the second timer means is started earlier (t _3). Here, if it is confirmed that the second timer has timed out in the next S6, the frame rod 1
Burner group 4 in S7 regardless of the presence or absence of flame detection by 6a
The combustion of a and 4b is stopped.

Next, at step S8, the frame rod 16
When the flame is detected by (a) (t ₄ ), the main solenoid valve 13c is opened in S9, and the fire burns to the burner group 4c, and the entire burner 4 burns. Subsequently, the detection of a flame by the flame rod 16b is made in the determination of S10 (t _5),
In S11, a first timer based on a preset heat retention time is started. Then, if the first timer times out in the determination of S12 (t ₆ ), the original solenoid valve 11,
The main solenoid valves 13a to 13c and the proportional control valve 12 close, respectively, and the combustion of the burner groups 4a to 4c is stopped.
If the second timer times out in the determination of, the combustion is stopped in S13. The control from S2 to S13 is repeated when the water temperature in the appliance decreases due to heat radiation.

Incidentally, the second timer is provided by the O
Time from N to flame detection by frame rod 16a,
That is, the time T ₁ that is the sum of the time required for the fire to reach the burner groups 4 a and 4 b and the rise time required for the current value of the flame rod 16 a to reach the flame determination level, and the main solenoid valve 13 c
Time from valve opening to flame detection by the frame rod 16b, i.e., the time T ₂ obtained by combining the rise time to the current value of the flame diffusion time and frame rod 16b to the burner group 4c reaches the flame determination level to be set in the first timer does not exceed the same incubation time T ₃ the combustion limit time Tmax plus time. For example, the time T ₁ is 0.8 sec, the time T ₂ is 0.15 sec, when the incubation time T ₃ is 1.2 sec, the combustion limit time Tmax _{is, T 1 + T 2 + T} 3 = 2.
15 seconds.

Therefore, according to the water heater 1, in addition to the first timer of the normal warming time started from the timing of flame detection by the frame rod 16a, the proportional control valve 12 is turned on in the counting of the warming combustion time. By providing a second timer for the combustion upper limit time to be started and stopping the warming combustion at the time of either one of them, the flame detection timing t ₄ , due to the temporal deterioration of the frame rods 16 a, 16 b, due to the delay of t _5, greater delay than the occurrence time of the first timer is actual flame to start, even if the time is up is slow (t
₆ '), the warm combustion is reliably stopped within the combustion upper limit time Tmax by the second timer. Therefore, the supply of an excessive amount of heat to the inner body 2 and the associated boiling and the possibility of deterioration of the inner body are eliminated. In the above embodiment, all the burner groups (17
The heat retention combustion is performed by using the above-mentioned method, in order to reduce the amount of heat per burner by burning all the burners, and to avoid local concentration of the heat amount in the inner body.

Further, in the above embodiment, the combustion upper limit time of the second timer is calculated by adding the heat retention time to the time for transferring to the burner group and the rising time of the flame rod, but is based on the actual combustion of the burner. Since the object of the present invention can be achieved by setting the upper combustion limit time, the upper limit combustion time may be set by the rise time and the heat retention time without considering the fire transfer time. Further, the timing at which the second timer starts is from when the proportional control valve is turned on, but may be started in accordance with the turning on of other control valves such as the original solenoid valve and the main solenoid valve.

[0013]

According to the first aspect of the present invention, in addition to the timer means for the normal heat retention time, the second timer means for the combustion upper limit time started by opening the control valve is provided, whichever is earlier. Even if the time-up of the timer means may be later than the time-up of the second timer means due to the delay of the flame detection by the flame detection means, the second timer The warm combustion is reliably stopped within the combustion upper limit time by the means.
Thus, the supply of an excessive amount of heat to the inner body, and the associated boiling and deterioration of the inner body can be eliminated.

[Brief description of the drawings]

FIG. 1 is a schematic view of a water heater with a heat retaining function.

FIG. 2 is a flowchart of heat retention control.

FIG. 3 is a time chart of heat retention control.

FIG. 4 is a time chart of a conventional heat retention control.

[Explanation of symbols]

1. Hot water heater with heat retention function, 2. Inner body, 3. Water pipe,
4 burner, 4a-4c burner group, 5 heat exchanger, 6 tap water pipe, 9a inner body temperature sensor, 10 controller, 11 original solenoid valve, 12 proportional Control valve,
13a to 13c: a main solenoid valve, 14: an igniter, 15: an ignition electrode, 16a, 16b, a frame rod, 18: an insulated switch.

Claims (1)

[Claims] 1. A burner, a control valve for controlling the supply of fuel gas to the burner, flame detecting means for detecting the flame of the burner, and timer means for starting the flame detection by the flame detecting means. A water heater with a heat retaining function that can maintain the water temperature in the appliance within a predetermined temperature range by burning the burner for a predetermined heat retaining time by the timer means in a water stopped state, wherein the burner is ignited. A second timer means is provided which starts by opening the control valve and sets a combustion upper limit time obtained by adding at least a rise time from ignition of the burner to detection of a flame by the flame detection means to a warming time by the timer means. A water heater with a heat retention function, wherein the burner is stopped when the timer expires, whichever is earlier, of the timer means and the second timer means.