JPH08285281A - Ignition burner in premixing burner - Google Patents

Abstract

PURPOSE: To make it possible to combust an ignition fuel gas in a favorable state near a theoretical air fuel ratio, and detect flames surely in the case when a flame rod is used as a flame detector, and perform a safe automatic control operation of a premixing burner in a burner which combusts a premixed gas of fuel gas and air on a flame holding surface formed on the downstream end part. CONSTITUTION: In an ignition burner 4 which is installed for the formation of a pilot flame in a premixing burner 1 which mixes a fuel gas 10 and air 11 and burns the mixed fuel gas on a flame holding surface 3 in a cylinder- shaped main body 2 where the flame holding surface 3 is formed on the downstream end, an ignition gas supply pipeline 5 is connected to the upstream end located in the cylinder-shaped main body 2 while a mixing pipeline 4a, wherein an air inlet 4c is formed, is mounted in the cylinder-shaped main body 2, allowing an injection pipe 4b formed on the downstream end of the mixing pipeline 4a to be flush with the flame holding surface 3 of the premixing burner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to form a pilot flame in a premixing burner in which a premixed mixture of fuel gas and air is burned on a flame holding surface formed at a downstream end. The present invention relates to an ignition burner in a premixing burner capable of more uniformly mixing the ignition gas with air and combusting it well to form a strong flame pilot.

[0002]

2. Description of the Related Art As a gas burner for burning a fuel gas, a premix burner for injecting and burning a mixture of fuel gas and air in advance from a downstream end of the mixture burns a mixture of fuel gas and air. Since it can be made uniform and can perform combustion close to complete combustion, it is used in many cases including when it is used for heating hot water for bath.

A general premixing burner 1'for heating hot water for bath, for example, will be briefly described with reference to FIG.
As shown in FIG. 2, a tubular body 2 for mixing the fuel gas 10 and the air 11, a fuel gas supply pipe 8 and a blower 9 respectively provided on the upstream side of the tubular body 2, and the tubular body 2
Of the flame holding surface 3 formed at the downstream end of the cylinder body 2, and the fuel gas 10 supplied from the fuel gas supply pipe 8 and the air 11 supplied from the blower 9 on the upstream side of the tubular body 2. Can be mixed while reaching the flame holding surface 3 formed at the downstream side end, and burned while being jetted from the flame holding surface 3 in the state of the air-fuel mixture 12.

In order to maintain the temperature of the hot water in the bathtub or the hot water stored in the bathtub to be supplied to the bathtub at a predetermined temperature, the premix burner 1'provides a fuel when the temperature of the hot water is equal to or higher than the predetermined temperature. When the supply of the gas 10 is stopped and when the temperature falls below a predetermined temperature, the fuel gas 10 is supplied and mixed with the air 11 blown in the tubular body 2 to form a mixture.
It is common to perform automatic control operation in which 12 is ignited on the flame holding surface 3. A normal ignition burner 4'is installed in order to quickly perform such an automatic control operation, and at the time of stop, the ignition gas 7 is burned by the ignition burner 4'to form a pilot fire. When the operation of the mixing burner 1'is restarted, the fuel gas 10 is supplied so that the ignition can be quickly performed. Further, in order to safely perform the above operation, a flame detector (not shown) for detecting a flame burning on the flame holding surface 3 is provided. As the flame detector, a flame rod is widely used because the above premix burner burns the fuel gas 10.

As a conventional ignition burner 4'installed in the premix burner 1 ', for example, as shown in FIG. 4, an ignition gas supply pipe 5 has its tip on the flame holding surface 3 of the premix burner 1'. Although the structure installed facing each other can be shown, the flame formed by burning the ignition gas 7 by the ignition burner 4 ′ has the tip of the ignition gas supply pipe 5 for the premixing burner 1 ′. Since the ignition gas 7 supplied from the ignition gas supply pipe 5 is a so-called diffusion flame that is ejected and burns on the same surface as the flame holding surface 3, the fuel consumption is poor. In addition, since the flame is weak, there is a drawback in that when the flame rod is used as the flame detector, the flame cannot be detected even though the flame is formed.

That is, the flame rod uses the rectification effect of the flame, and utilizes the fact that the ion concentration in the flame is high. Therefore, the flame is detected by inserting the electrode directly into the flame and detecting the current flowing through the electrode. Since the ion (+ charge) has a slow moving speed, the ion concentration in the high temperature combustion gas is large in the initial combustion region and small at the position away from the flame holding surface where the electrode is inserted. Thus, the current flows strongly only when the flame holding surface 3 side has a negative potential. The maximum current flows when the air amount of the burning gas is the theoretical air amount, and a large current can be obtained by arranging the electrode at a position in contact with the inner flame of the flame. Therefore, when the ignition gas 7 is burned by the conventional ignition burner 4 ', the flame is weak and only a small amount of current flows through the flame rod as described above. There was a drawback that sometimes it could not detect the flame. Thus, if the flame of the ignition burner 4'is not detected by the flame rod even if the ignition gas 7 is in a burning state, the malfunction of stopping the supply of the ignition gas 7 and the operation of the blower 9 occurs. Premix burner 1 '
However, there was a drawback in that it could not be operated smoothly and automatically.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art and burns a mixture of fuel gas and air in advance on a flame-holding surface formed at the downstream end. In the premix burner, the ignition gas for forming the pilot flame is more uniformly mixed with the air so that the ignition gas can be satisfactorily combusted even if the lower limit supply amount of the ignition gas to be supplied is reduced, and flame detection is performed. An object of the present invention is to provide an ignition burner in a premixing burner that can safely perform automatic control operation because a flame can be reliably detected even if a frame rod is used as a vessel.

[0008]

As a result of various studies to solve the above problems, the present inventor mixed fuel gas and air in a tubular main body having a flame holding surface formed on the downstream end. In an ignition burner for forming a pilot flame, which is installed in a premixing burner that burns at least on the flame holding surface,
A mixing pipe, in which an ignition gas supply pipe is connected to an upstream end located in the tubular body and an air blowing port is formed, is formed at a downstream end of the mixing pipe. The present invention has been completed by discovering that the above problems can be solved if the ejecting pipe is mounted so as to face the flame holding surface of the premixing burner.

The ignition burner in the premix burner according to the present invention will be described in detail below with reference to the drawings. FIG.
Is one of the burners for ignition in the premix burner according to the present invention.
A sectional explanatory view showing a state in which a premix burner equipped with an embodiment is operating, and FIGS. 2 and 3 are premix equipped with another embodiment of the ignition burner in the premix burner according to the present invention. FIG. 4 is a cross-sectional explanatory view showing a main part of the burner in a state where its operation is stopped.

In the drawing, reference numeral 1 designates a tubular body 2 for mixing a fuel gas 10 and air 11, and a fuel gas 10 and air in the tubular body 2 which are formed at the downstream end of the tubular body 2. 11 is a premixing burner provided with a flame holding surface 3 for injecting and burning a mixed air-fuel mixture 12, and normally supplies the fuel gas 10 to the upstream side of the cylindrical main body 2 as shown in FIG. A blower 9 provided with a fuel gas supply pipe 8 and supplying air 11 further upstream of the fuel gas supply pipe 8.
Is provided.

The flame-holding surface 3 is one that has been generally used in the past, for example, two punched plates 3a having a large number of through holes formed therein are provided at intervals and the punched plates 3a are punched. It can be shown that the wire netting 3b is inserted between the blanks 3a. The punching plate 3a and the wire netting 3b at predetermined positions on the flame holding surface 3 having such a structure are formed with a jetting pipe insertion port 3c into which a jetting pipe 4b of a premixing burner 4 described later is inserted.

Reference numeral 4 denotes a mixing pipe 4a in which an ignition gas supply pipe 5 is connected to an upstream end located in the tubular body 2 and an air blowing port 4c is formed. The ejection pipe 4b formed at the downstream end of the same is faced with the flame holding surface 3 of the premix burner 1, that is, in the illustrated embodiment, the ejection pipe insertion port 3c of the flame holding surface 3 In squirt tube 4b
Of the ignition burner in the premix burner according to the present invention installed in the cylindrical main body 2 in a state where the tip thereof is inserted into contact with the back surface of the punching plate 3a on the downstream side (hereinafter, simply referred to as ignition burner). Sometimes called a burner).

The mixing pipe 4a can mix the air 11 in the cylindrical main body 2 of the premixing burner 1 blown from the air blowing port 4c and the ignition gas 7 supplied from the ignition gas supply pipe 5 more uniformly. It is preferable that the length is as long as possible, but for example, in the case of a cylindrical mixing tube 4a having an inner diameter of 10 mm, it is 40
Mix well if it has a length of about mm.

The air injection port 4c formed at the upstream end of the mixing pipe 4a may have a configuration in which a through hole 4cb is simply formed in the mixing pipe 4a as shown in FIGS. 2 and 3. ,
As shown in FIG. 1, a female screw is screwed on the upstream end of the mixing pipe 4a, and a pipe body 4ca having a predetermined inner diameter and a male screw on the outer peripheral surface is screwed into this female screw. It is possible to easily blow the amount of the air 11 blown into the tubular body 2 of the premixing burner 1 into the mixing pipe 4a by exchanging the pipes 4ca having different inner diameters. Since it can be adjusted, an optimum amount of air 11 corresponding to the ignition gas 7 supplied to the mixing pipe 4a can be blown into the mixing pipe 4a from the inside of the cylindrical main body 2, which is preferable.

The ignition gas supply pipe 5 connected to the upstream end of the mixing pipe 4a may be integrally formed with the mixing pipe 4a, but the upstream end of the mixing pipe 4a as in the illustrated embodiment. It is preferably connected to the section via a connecting tool 5c. The ignition gas supply pipe 5 is connected to the mixing pipe 4a through the ignition gas inlet 5a.
It is also possible that the nozzle-shaped ignition gas injection port 5a is formed at the upstream end of the mixing pipe 4a as shown in FIG. 3, but it is formed in the connector 5c as shown in FIG. Ignition gas inlet 5a and mixing pipe 4a as shown in FIG.
The ignition gas amount adjustment valve 5b for adjusting the opening of the ignition gas inlet 5a formed at the upstream end of the is different from the optimum ignition depending on the type of ignition gas used. This is preferable because the supply amount of the working gas can be easily adjusted. As a means for adjusting the ignition gas amount adjusting valve 5b, when the normal premixing burner 1 is installed when the premixing burner 1 is used to heat hot water for bath, etc. Since it is not necessary to adjust the supply amount of the ignition gas 7 after setting the supply amount of the ignition gas 7 in accordance with the size of the mixing pipe 4a and the type of the ignition gas 7, inexpensive mechanical adjustment is possible. Means may be used.

Such an ignition burner 4 is preferably detachably mounted in the cylindrical main body 2 of the premixing burner 1 for easy repair and inspection. For example, in the illustrated embodiment, premixing is performed. A mounting hole 2a is formed at a predetermined position of the cylindrical main body 2 of the burner 1, and the ignition gas supply pipe 5 and the mixing pipe 4a are connected to each other via a connector 5c. A flange 6 for closing is formed on the connecting tool 5c so that the mixing pipe 4a is inserted into the cylindrical main body 2 from the mounting hole 2a and the ejection pipe 4b faces the flame stabilizing surface 3 and the flange is formed. 6 with premixed burner 1 tubular body 2
The mounting hole 2a is positioned so as to be closed, and the flange 6 is screwed to the tubular main body 2 of the premix burner 1 via the gasket 6a.

[0017]

In the ignition burner 4 of the premixing burner according to the present invention having the above-described structure, the premixing burner 1 generally has the flame holding surface 3 of the premixing burner 1 when the temperature of the hot water drops below a predetermined temperature. Since the fuel gas 10 is burned, and when the warm water rises above a predetermined temperature, the supply of the fuel gas 10 is stopped and the operation of the premix burner 1 is stopped. While the operation is stopped, the supply of the fuel gas 10 is stopped, but the blower 9 is blown into the tubular body 2, and the air 11 in the tubular body 2 is mixed with the mixing pipe of the ignition burner 4. The ignition gas 7 is blown into the mixing pipe 4a through an air inlet 4c formed at the upstream end of the mixing pipe 4a, and the ignition gas 7 is mixed from an ignition gas supply pipe 5 connected to the upstream end of the mixing pipe 4a. Supplied in the tube 4a,
The air 11 and the ignition gas 7 are mixed in the mixing pipe 4a.

Since the mixing pipe 4a of the ignition burner 4 has a certain length, the air 11 and the ignition gas 7 are more uniformly mixed and ejected from the ejection pipe 4b at a constant air-fuel ratio. It can be made to burn and the pilot flame can be what is called a premixed flame. Therefore, the combustion of the ignition gas 7 can be a combustion with the air-fuel ratio of the ignition gas 7 close to the lower limit value, and can be always a good combustion.
It is possible to efficiently form a strong flame pilot fire.

At this time, a pipe body is provided at the upstream end of the mixing pipe 4a as an air blowing port 4c formed at the upstream end of the mixing pipe 4a.
Ignition gas which is formed by detachably screwing 4ca or which can adjust the opening degree of the ignition gas injection port 5a for injecting the ignition gas 7 from the ignition gas supply pipe 5 into the mixing pipe 4a. When the amount adjusting valve 5b is provided, the optimum supply amount of the ignition gas 7 according to the type of the ignition gas 7 to be used and the flow rate of the air 11 blown into the cylindrical main body 2 of the premix burner 1 Can be easily adjusted.

When the premix burner 1 is in operation, the fuel gas 10 is supplied from the fuel gas supply pipe 8 and the air 11 is blown from the blower 9. Since the air-fuel mixture 12 in which the fuel gas 10 and the air 11 are mixed is flowing, the air-fuel mixture 12 in the tubular main body 2 is formed at the upstream end of the mixing pipe 4a of the ignition burner 4. The ignition gas 7 is blown into the mixing pipe 4a through the air blowing port 4c and is supplied into the mixing pipe 4a from the ignition gas supply pipe 5 connected to the upstream end of the mixing pipe 4a. Therefore, since the air-fuel mixture 12 and the ignition gas 7 are mixed in the mixing pipe 4a of the ignition burner 4, the air amount of the air-fuel mixture ejected from the ejection pipe 4b is small, but the combustible air-fuel ratio is Since the flame formed by the ignition burner 4 has a long length, combustion is maintained, and the flame holding surface 3 of the premixing burner 1 has fuel gas 10 and air 11 Since the air-fuel mixture 12 in which is mixed is burned in a good state, the flame can be reliably detected even when the flame rod is used as the flame detector.

Further, in the ignition burner 4, the ignition gas supply pipe 5 and the mixing pipe 4a are connected to each other through a connecting member 5c, and a flange 6 for closing the mounting hole 2a is formed in the connecting member 5c. And a mounting hole formed in the tubular main body 2 of the premix burner 1 through the gasket 6a.
If it is detachably attached to the tubular body 2 as in the case of being fixed to the tubular body 2 so as to close the 2a, repair and inspection can be easily performed.

[0022]

As described above in detail, the ignition burner in the premixing burner according to the present invention comprises the ignition gas and the air in the tubular body from the upstream end of the mixing tube having a certain length. Are supplied and premixed in the mixing pipe, the ignition gas and the air can be mixed more uniformly, and a mixture having a constant air-fuel ratio can be obtained. It can be used as a fire and can be burned in a state where the air-fuel ratio of the ignition gas is close to the lower limit value.Also, good combustion can be always achieved and fuel consumption is excellent, and safe driving is performed. Therefore, when a flame rod is used as a flame detector that is usually installed in a premix burner, a strong flame can be used as the seed flame, so a strong current can be generated in the flame rod, and the ignition gas Is burning Without also malfunction such as to stop the supply of the ignition gas irrespective there occurs smoothly and safely can be automatically controlled operation of the premix burner.

Further, as an air injection port formed at the upstream end of the mixing pipe, a pipe body is detachably screwed at the upstream end of the mixing pipe, or an ignition gas supply pipe. If there is an ignition gas amount adjustment valve that adjusts the amount of ignition gas blown into the mixing pipe from the device, the amount of air blown into the mixing pipe and the amount of ignition gas used depending on the type of ignition gas used. It is possible to easily adjust the optimum supply amount of the ignition gas that varies depending on the type of gas, and to form the ignition gas into a pilot fire in a better combustion state.

Further, since the ejection pipe formed at the downstream end of the mixing pipe is mounted so as to face the same surface as the flame holding surface, the ignition burner is restarted when the operation of the premixing burner is restarted. Ignition of the main flame of the premixed burner from the pilot fire formed by is safely and reliably performed.

As described above, the ignition burner in the premix burner according to the present invention having various effects is of great industrial value.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing a state in which a premixing burner equipped with an embodiment of an ignition burner in a premixing burner according to the present invention is operating.

FIG. 2 is a cross-sectional explanatory view showing a main part of a premix burner equipped with another embodiment of the ignition burner in the premix burner according to the present invention, in a state where its operation is stopped.

FIG. 3 is a cross-sectional explanatory view showing a main part of a premixing burner equipped with another embodiment of the ignition burner in the premixing burner according to the present invention, the operation of which is stopped.

FIG. 4 is an explanatory cross-sectional view showing an ignition burner in a conventional premix burner.

[Explanation of symbols]

 1 premix burner 1'conventional premix burner 2 cylindrical body 2a mounting hole 3 flame holding surface 3a punching plate 3b wire mesh 3c spout pipe insertion port 4 ignition burner according to the present invention 4a mixing pipe 4b spout pipe 4c air blowing Port 4ca Tubular body 4cb Through hole 4'Conventional ignition burner 5 Ignition gas supply pipe 5a Ignition gas injection port 5b Ignition gas amount adjusting valve 5c Connection tool 6 Flange 6a Gasket 7 Ignition gas 8 Fuel gas supply pipe 9 Blower 10 Fuel gas 11 Air 12 Mixture

Claims (4)

[Claims] 1. A flame holding surface (3) is prepared by mixing a fuel gas (10) and air (11) in a cylindrical body (2) having a flame holding surface (3) formed at a downstream end thereof. ) Premix burner (1)
Ignition burner installed at
In (4), a mixing pipe in which an ignition gas supply pipe (5) is connected to an upstream end located inside the cylindrical main body (2) and an air blowing port (4c) is formed. (4a) is the mixing tube
The jet pipe (4b) formed at the downstream end of (4a) is mounted so as to face the same surface as the flame holding surface (3) of the premixing burner (1). Ignition burner for premixed burner. 2. An ignition gas amount adjusting valve (5b) for adjusting the injection amount of the ignition gas (7) blown into the mixing pipe (4a) from the ignition gas supply pipe (5). Ignition burner in the premix burner described in 1. 3. The air inlet (4c) of the mixing pipe (4a) is a mixing pipe.
A female screw is screwed on the upstream end of (4a), and a pipe (4ca) having a predetermined inner diameter and a male screw on the outer peripheral surface is screwed into the female screw. Claim 1 or 2 formed
Ignition burner in the premix burner described in 1. 4. The air inlet (4c) of the mixing pipe (4a) is a mixing pipe.
An ignition burner for a premix burner according to claim 1 or 2, wherein the burner is a through hole (4cb) formed at the upstream end of (4a).