JPH04324021A - Combustion controller of gas combustion apparatus - Google Patents

Abstract

PURPOSE:To offer a combustion controller of a combustion apparatus in which generation of combustion vibration is eliminated or restrained even when the operating number of burners is increased. CONSTITUTION:A combustion controller of a gas combustion apparatus which at least includes two or more burners 2 and 3, a fan 5 that supplies combustion air, a gas pressure regulator 7 that regulates the pressure of combustion gas, a burner operating number changeover device 8 that changes the operating number of the burners 2 and 3, and a controller 13 that controls the actions of devices in the combustion apparatus. When the operating number of the burners is increased, the controller 13 starts first temporary reducing action of the rotating speed of the fan 5 and the gas pressure by the gas pressure regulator 7, and makes the burner operating number changeover device 8 operate with a little delay after the reducing action is started.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control device for a gas combustor.

0002

[Prior Art] Conventionally, in a combustor such as a gas water heater,
A gas combustor is provided in which the number of burners is switched from a small number to a large number according to the usage capacity. FIG. 4 shows a timing chart of capacity switching in such a conventional gas combustor. That is, conventionally, when changing the capacity to increase the number of burners used, the operation of lowering the fan rotation speed, the operation of lowering the gas pressure, and the operation of the burner number switching means were performed simultaneously as shown by the arrow. After a holding time of about 1 second, the fan rotation speed and gas pressure were returned to their original values. As described above, by once lowering the fan rotation speed and gas pressure to a state suitable for ignition, it is possible to ensure ignition of additional burners when the number of burners is increased.

0003

However, in the conventional apparatus described above, there is a problem in that combustion vibration occurs when the number of burners is switched, specifically at the moment when the additional burner is ignited. That is, the flame sways when ignited, causing the appliance to vibrate.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a combustion control device for a gas combustor that can eliminate or suppress the occurrence of combustion oscillations even when the number of burners is changed to increase. shall be.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present inventor investigated the cause of the above phenomenon and found that the fan rotation speed and gas pressure are slightly lower than they actually are due to the switching operation. Immediately after the switching operation, the fan rotation speed and gas pressure are still high, and as a result, when the burner number switching operation is performed at the same time as the fan rotation speed reduction operation and the gas pressure reduction operation, the fan rotation speed and gas pressure are still high. Ignition occurs at fan speed and gas pressure, so
It was discovered that the above-mentioned combustion oscillation occurs, and the present invention was developed.

That is, the apparatus of the present invention includes a plurality of burners, a fan for supplying air for combustion, a gas pressure adjusting means for adjusting the gas pressure of fuel gas, and a burner number switching means for switching the number of combustion burners. , a combustion control device for a gas combustor, which includes at least a controller that controls the operation of each part of the combustor, and when switching to increase the number of combustion burners, first, the fan rotation speed and gas pressure are adjusted by the fan and the gas pressure adjusting means. The present invention is characterized in that the burner number switching means is configured to start a temporary lowering operation, and to operate the burner number switching means with a slight delay in these operations.

[0007]

[Operation] According to the feature of the present invention, when switching to increase the number of combustion burners, the fan and the gas pressure adjusting means first start a temporary operation of decreasing the fan rotation speed and the gas pressure, and then these operations are performed. The burner number switching means operates with a slight delay. Therefore, when the burner number switching means operates, the fan rotation speed and gas pressure have already decreased to a state suitable for ignition, and ignition can be performed with combustion vibrations sufficiently suppressed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on embodiments shown in the drawings. FIG. 1 is an overall configuration diagram of a gas combustor showing an embodiment of the present invention, FIG. 2 is a control flowchart for switching the number of burners by a controller, and FIG. 3 is a timing chart for switching the number of burners.

This embodiment is a gas combustor configured as a gas instantaneous water heater. Two burners 2 and 3 are provided inside the can body 1, and a heat exchanger 4 is provided at the top. Further, air for combustion is supplied into the can body 1 by a fan 5. Fuel gas is supplied to the burners 2 and 3 via an on-off valve 6, a gas pressure regulating valve 7 as a gas pressure regulating means, and a burner number switching valve 8 as a burner number switching means. Further, a water supply pipe 10 is connected to the heat exchanger 4 via a water cabana (not shown), a water temperature sensor, and a water flow rate sensor 9, and a water supply pipe 10 is connected from the heat exchanger 4 to a hot water outlet pipe 12 equipped with a hot water temperature sensor 11 and a hot water outlet (not shown). has been extended. The operation of each part of the combustor is controlled by a controller 13. Further, the hot water temperature can be set using the remote control 14. 15 is an igniter, and 16 is a flame detector.

[0010] When using hot water supply, turn on the operation switch of the remote control 14 and open the hot water tap. As a result, when the water amount sensor 9 detects the minimum operating water amount or more, pre-purging is performed by the fan 5 via the controller 13 for a certain period of time, the main on-off valve 6 is opened, the igniter 15 is activated, and the burner 2 or 3, or 2 and 3 are lit. When the hot water temperature is set by the remote control 14, the required number (combustion capacity) is calculated from the incoming water temperature, set temperature, and incoming water flow rate, and the gas pressure control valve 7 is adjusted accordingly. The burner number switching valve 8 is operated to switch the number of burners.

Next, the control by the controller 13 when increasing the number of burners (from one to two in the embodiment) will be explained with reference to FIGS. 2 and 3. Now, if the hot water supply temperature setting is reset to a high temperature during combustion, or the amount of hot water dispensed by the hot water tap is increased, the controller 13 calculates a new required number (step 51).
). Then, it is determined whether or not there is a need to change the number of burners from the current number (step 52), and if a change is required, it is determined whether or not further increase switching is required (step 53). In the case of increase switching, first fan 5
Then, the gas pressure regulating valve 7 is started to lower the ignition rotation speed and the ignition gas pressure (step 54). For example, in the case of the fan 5, this reduces the applied voltage and reduces the applied voltage to the gas control valve 7.
In this case, reduce the opening degree of the valve.

[0012] After the operation of step 54, a certain period of time a,
In the embodiment, when 0.5 seconds have elapsed (step 55
), the increase switching operation of the burner number switching valve 8 is performed (step 56). This ignites the boost burner. Then, for a further certain period of time b, in the example, 0.
After holding for 5 seconds (step 57), the fan 5 and gas control valve 7 are adjusted to the predetermined rotational speed and gas pressure calculated above (step 59). Note that the certain times a and b
are not limited to 0.5 seconds each, and other suitable short times can be adopted.

It should be noted that if it is determined in step 53 that the changeover to increase the number of burners is YES, the controller 13
It is also possible to issue a command to switch the number of burners at the same time as a command to reduce the fan rotation speed and gas pressure, and from that point on, steps 56 and 59 may be actually operated with respective delay times. Of course, the commands themselves from the controller 13 are shifted respectively and step 5 is performed.
6 and 59 may be performed.

If it is determined in step 52 that the number of burners does not need to be changed, the process proceeds to step 59 and the fan rotation speed and gas pressure are adjusted to the calculated predetermined number. If the determination in step 53 is NO and the number of burners is to be decreased, the process proceeds to step 58, where the burner number switching valve 8 is operated to reduce the number of burners, and then the process proceeds to step 59.

In FIG. 3, if an adjustment command is issued for the fan 5 and gas pressure regulating valve 7 at time A, it will take some time for the fan rotation speed and gas pressure to actually decrease to the ignition rotation speed and ignition gas pressure. Since it takes time, the burner number switching means is turned on once the time has elapsed and a stable state has been reached.

[0016]

Effects of the Invention The present invention consists of the above configuration, and claim 1
According to the combustion control device for a gas combustor described in , when switching to increase the number of combustion burners, the fan and the gas pressure adjusting means first start a temporary operation of decreasing the fan rotation speed and the gas pressure, and then Since the burner number switching means operates with a slight delay in these operations, by the time the burner number switching means operates, the fan rotation speed and gas pressure have already decreased to a state suitable for ignition. Therefore, ignition is achieved with combustion vibrations sufficiently suppressed. That is, oscillating combustion can be suppressed.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of a gas combustor showing one embodiment of the present invention.

FIG. 2 is a control flowchart for switching the number of burners by a controller.

FIG. 3 is a timing chart for switching the number of burners.

FIG. 4 is a timing chart of capacity switching in a conventional gas combustor.

[Explanation of symbols]

2, 3 Burner 5 Fan 6 Original on-off valve 7 Burner number switching valve 13 Controller

Claims (1)

[Claims] 1. A plurality of burners, a fan for supplying air for combustion, a gas pressure adjusting means for adjusting the gas pressure of fuel gas, a burner number switching means for switching the number of combustion burners of the burner, and each part of the combustor. A combustion control device for a gas combustor, which includes at least a controller for controlling the operation of a burner, and when switching to increase the number of combustion burners, first, the fan rotation speed and gas pressure are temporarily adjusted by the fan and gas pressure adjusting means. A combustion control device for a gas combustor, characterized in that the burner number switching means is configured to start a lowering operation and operate the burner number switching means with a slight delay in these operations.