JPH1089678A - Ignition method of gas burning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely prevent back fire from occurring at ignition in a gas burning apparatus that performs thick and thin combustion. SOLUTION: There are provided a plurality of thin gas burner parts 6, 6 each for injecting and combusting thin mixture gas, a plurality of thick gas burner parts 7, 7 provided between the thin gas burner parts 6, 6 for injecting and combusting higher concentration thick mixture gas than the diluted mixture gas, fuel supply means 8 for supplying fuel gas to both burner parts 6, 7, and ignition means 9. Upon ignition operation of the ignition means 9, starting of fuel supply to the thin burner parts 6, 6 by the fuel supply means 8 is retarded by a predetermined time against that to the thick burner parts 7, 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for igniting a gas combustion device used in a gas water heater, a gas hot water heater, or the like, and more particularly, to a light gas burner for injecting and burning a lean gas mixture having a low gas concentration, The present invention relates to a method for igniting a gas combustion device including a rich gas burner section for injecting and burning a rich mixed gas having a higher gas concentration than a lean mixed gas.

[0002]

2. Description of the Related Art Conventionally, as this type of gas combustion apparatus,
For example, as disclosed in Japanese Patent Application Laid-Open No. 5-322113 and the like, a plurality of light gas burners for injecting and burning a lean mixed gas, and a plurality of light gas burners provided between the light gas burners,
A plurality of rich gas burners for injecting and burning a rich mixed gas having a gas concentration higher than that of the lean mixed gas;
The generation amount of Ox was reduced.

[0003]

In the conventional apparatus having the above-described structure, the light gas burner and the rich gas burner simultaneously ignite and burn at the time of ignition. For example, when the gas combustion apparatus is used in a gas water heater. At the time of ignition, temporary air expansion occurs in a combustion furnace such as a heat exchange cylinder,
The furnace pressure rises excessively. At this time, since the pressure of the mixed gas ejected from the lean gas burner is lower than that of the rich gas burner, an excessively increased furnace pressure is applied to the inside of the lean gas burner through the flame hole, and the flame is generated in the lean gas burner. There was a problem of getting back into the fire.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to reliably prevent occurrence of flashback at the time of ignition in a gas combustion device that performs rich and light combustion.

[0005]

According to the present invention, a plurality of lean gas burners for injecting and burning a lean mixed gas and a rich mixed gas having a higher gas concentration than the lean mixed gas are provided between the lean gas burners. A plurality of rich gas burners for burning, fuel supply means for supplying fuel gas to both burners, and ignition means, wherein when the ignition means operates, fuel supply to the light burner section by the fuel supply means is started. Is delayed by a predetermined time from the start of fuel supply to the rich burner section.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a gas water heater to which a gas combustion device according to the present invention is applied, and FIG. 2 is a time chart illustrating an operation example of a control device.

In FIG. 1, a gas water heater 1 has a finned heat exchanger 2 at a lower part of a heat exchange cylinder 3 having an upper part.
A gas combustion device A for heating the heat exchanger 2 with combustion gas is provided. The gas combustion apparatus A includes a burner case 4, a blower (FM) 5 for supplying combustion air, a plurality of light gas burners 6, 6 housed in the burner case 4 and ejecting and burning a lean mixed gas. A plurality of dense gas burners 7, 7 disposed between the lean gas burners 6, 6 for injecting and burning a rich mixed gas having a higher gas concentration than the lean mixed gas ejected from the lean gas burners 6, 6; A fuel supply device 8 for supplying gaseous fuel to the sections 6 and 6 and the rich gas burners 7 and 7, and an ignition plug (IG) 9.
And a frame sensor 10 and the like.

The fuel supply device 8 includes a fuel gas supply passage 1
1, a first solenoid valve (SV1) 12, a proportional valve (PCV) 13, and a second solenoid valve (SV2) 14 are interposed in that order from the upstream side thereof, and the second solenoid valve (SV2) )
On the downstream side of 14, a first path 15 through which gas fuel supplied to each of the lean gas burners 6, 6 flows, and a rich gas burner 7,
The fuel gas supply path 11 is branched into a second path 16 through which gas fuel to be supplied to the fuel cell 7 flows.
A third solenoid valve (SV3) 17 is provided upstream of the path 15.

The ignition plug 9 is provided with a dense gas burner section 7,7.
The flame sensor 10 is provided to face one of the lean gas burners 6, 6, and the flame detection signal of the frame sensor 10 is:
Driving of the ignition plug (IG) 9 and the blower (FM) 5, the first solenoid valve (SV1) 12, the proportional valve (PCV) 13, the second solenoid valve (SV2) 14, and the third
Is input to a controller 18 for controlling the combustion by controlling the opening and closing of an electromagnetic valve (SV3) 17.

At the time of ignition when a switch (SW) such as a running water switch is turned on, as shown in FIG. 2, the controller 18 first operates the blower (FM) 5 at a low speed to perform pre-purge, and the pre-purge time ( After the elapse of T1), the first solenoid valve (SV1) 12, the proportional valve (PC)
V) 13 and the second solenoid valve (SV2) 14 are opened and, at the same time, the ignition plug (IG) 9 is operated. After a lapse of a predetermined time (T2) from the opening operation of the second solenoid valve (SV2) 14, etc., the third solenoid valve (SV2)
3) Open the 17. The predetermined time (T2) is set to a short time of about 0.5 to 2 seconds. Then, when ignition is confirmed by the flame detection signal of the frame sensor 10, the operation of the ignition plug 9 is stopped.

In the above-described configuration, when a switch (SW) such as a water switch is turned on, the controller 18 performs a pre-purge by operating the blower (FM) 5 at a low speed, and after the lapse of the pre-purge time (T1), the first The ignition valve (SV1) 12, the proportional valve (PCV) 13, and the second solenoid valve (SV2) 14 are opened at the same time as the ignition plug (IG) 9 is operated. The first solenoid valve (SV1)
12, a proportional valve (PCV) 13 and a second solenoid valve (SV
2) By the opening operation of 14, gas fuel is supplied to each of the rich gas burners 7, 7 via the second path 16, and each of the rich gas burners 7, 7 is supplied with a rich mixed gas having a high gas concentration from its flame hole. And the concentrated mixed gas thus ejected is supplied to a spark plug (I
G) It is ignited by the spark discharge of 9.

The controller 18 operates for a predetermined time (T.sub.T) from the opening operation of the second solenoid valve (SV2) 14.
2) After the elapse, the third solenoid valve (SV3) 17 is opened. By the opening operation of the third solenoid valve (SV3) 17, the fuel gas is supplied to each of the lean gas burners 6, 6 through the first path 15, and the flame F of the rich gas burners 7, 7 is discharged to each of the lean gas burners. The mixture is burnt to the lean gas mixture ejected from the sections 6 and 6, and the lean combustion with a small NOx generation amount is performed.

According to this embodiment, the ignition plug (I
G) At the time of the ignition operation for activating the 9, the start of fuel supply to the lean gas burners 6, 6 by the opening operation of the third electromagnetic valve (SV 3) 17 is performed by the first electromagnetic valve (SV 1) 12,
Proportional valve (PCV) 13 and second solenoid valve (SV2) 14
Is delayed for a predetermined time (T2) of about 0.5 to 2 seconds from the start of fuel supply to the rich gas burners 7, 7 by the opening operation of the rich gas burners 7, 7. After the combustion in the rich gas burners 7 and 7 is stabilized, the lean mixed gas combustion is performed in the light gas burners 6 and 6, so that a rapid pressure rise in the heat exchange cylinder 3 at the time of ignition is reduced. As a result, flashback to the inside of each of the fresh gas burners 6, 6 is reliably prevented.

[0014]

As is apparent from the above description, the present invention has a plurality of light gas burners for injecting and burning a lean mixed gas, and a concentrated gas provided between these lean gas burners and having a higher gas concentration than the lean mixed gas. A plurality of rich gas burners for injecting and burning the mixed gas; fuel supply means for supplying fuel gas to both burners; and ignition means. Start of fuel supply is delayed by a predetermined time from start of fuel supply to the rich burner portion, so that a rapid rise in the pressure inside the furnace of the heat exchange cylinder or the like at the time of ignition can be mitigated, and the amount of NOx generated by the lean burn And the occurrence of flashback can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a gas water heater to which a gas combustion device according to the present invention is applied.

FIG. 2 is a time chart illustrating an operation example of a control device.

[Explanation of symbols]

 A gas combustion device 6 light gas burner section 7 rich gas burner section 8 fuel supply device (fuel supply means) 9 spark plug (ignition means)

Claims (1)

[Claims] 1. A plurality of light gas burners for injecting and burning a lean gas mixture, provided between the light gas burners,
A plurality of rich gas burners for injecting and burning a rich mixed gas having a higher gas concentration than the lean mixed gas, fuel supply means for supplying fuel gas to both burners, and ignition means,
A method for igniting a gas combustion device, wherein the start of fuel supply to the light burner section by the fuel supply means is delayed by a predetermined time from the start of fuel supply to the rich burner section during the ignition operation of the ignition means. .