JPH03158611A - Burner - Google Patents

Abstract

PURPOSE:To form a flame which creates no CO and no soot and is long and stable and reduce combustion noises by providing a flame hole on the downstream side of a premixing chamber, an opening which opens on a secondary air guide cylinder near the flame hole, and at the same time a tertiary air channel which goes through the central section of the flame hole and projects. CONSTITUTION:When the fuel gas from a combustion nozzle 3 and the air supplied by a blower 1 enter a premixing chamber 2, they mix together and flow to the sides of a flame hole 6. The other air passes through a secondary air channel 8 and it is divided by and supplied from the opening A7'' and the opening section B8' of a secondary air guide cylinder 7'. The mixture gas that is blown out from the flame hole 6 becomes a flame 13 by means of an ignitor 14. At this time the air from the secondary air channel 8 is supplied forcibly to the outer circumference of the flame 13 by the throttling section 12 of the opening section B8'. Further, tertiary air is supplied to the central section of the premixture gas from a tertiary air channel 15, and a flame 16 is formed on the downstream side of the central section of the flame hole 6. With this constitution in which air is supplied to the outside and inside of the premixture gas it is possible to provide stable combustion with no CO and no soot generated. And because of the long flame 13 formed in a combustion chamber 10 its inside is kept almost thermally uniform and at the same time it is possible to provide combustion with a low level of noises.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a combustion device for domestic use.

2. Description of the Related Art As shown in FIG. 2, this type of conventional combustion apparatus has an air swirling section 23 in a nozzle section 22 in a cylindrical combustion chamber 21, and performs combustion by vigorously mixing fuel and air ejected from the nozzle 22. In many cases, there are pre-mixing type diffusion combustors that premix the negative part of the air and eject it from a nozzle, and supply air for diffusion combustion around it. The aim has been to burn a mixture of fuels. In other words, it is undesirable for the flame to be long, and if it is too long, it will result in the generation of soot.

In addition, rapid mixing of air and fuel resulted in flame instability, and when the mixing was weakened, the above-mentioned soot was generated.

Problems to be Solved by the Invention In the above configuration, the combustion load is high, and although combustion can be completed in a small combustion chamber, the combustion part becomes very hot.
The durability of the material becomes an issue. On the other hand, if the flame is lengthened, its length will be limited due to the problem of soot or Co. According to experiments, a length of 20 to 25 cm is the limit.

The present invention solves these conventional problems, and makes it possible to form a long stable flame without producing Co or soot, which was previously considered impossible, and to obtain a long heating surface with low combustion noise and small temperature difference. purpose.

Means for Solving the Problems In order to solve the above problems, the combustion apparatus of the present invention includes a premixing chamber for mixing fuel t4 and air on the downstream side of the blowing means, and a fuel nozzle on the upstream side of the premixing chamber. A flame hole is provided on the downstream side of the premixing chamber, and a secondary air guide cylinder is extended concentrically with the flame hole from near the flame hole toward the downstream side, and a secondary air guide tube near the flame hole is provided. An opening is provided in the cylinder, the other end is open, and a tertiary air passage is provided extending from the premixing chamber through the center of the flame hole, and a secondary air passage is provided around the premixing chamber. and the tertiary air passage are in communication with each other.

Effect of the present invention With the above-described configuration, fuel and air are mixed in the premixing chamber by the operation of the blowing means and the fuel nozzle, the premixture is ejected from the flame hole into the combustion chamber, and at the same time, the air from the secondary air passage is is supplied to the outer periphery of the flame from the opening near the flame hole and the open end at the other end by the secondary air guide cylinder, and a flame is formed by the operation of the ignition means. Furthermore, tertiary air is supplied from the tertiary air passage to the central part of the premixture that is difficult for secondary air to reach, and a flame is formed downstream of the central part of the flame hole along the flow of this tertiary air. By dividing and supplying air into and out of the premixture in this way, the contact area between the fuel and air is increased, a double combustion reaction zone is formed, and stable combustion is achieved without the generation of Co or soot. Can be done. In addition, by supplying a part of the total amount of air from the tertiary air passage extending from the flame hole surface and dividing the secondary air and supplying it, the air flow velocity near the flame hole can be set to a small value. 2 at the flame hole
There is no violent reaction and the combustion noise can be lowered. Further, the secondary air encloses the flow of the premixture in the combustion chamber and is stretched to form a long, stable flame within the combustion chamber, so that the interior of the combustion chamber can be maintained thermally almost uniformly.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Fig. 1, l is a blowing means such as an axial fan;
The dashed arrow indicates air. Reference numeral 2 denotes a substantially cylindrical premixing chamber, and a fuel nozzle 3 for injecting fuel (gas) from a fuel pipe 4 into the premixing chamber 2 faces on the upstream side. Solid arrows indicate gas. Reference numeral 5 denotes a perforated plate provided in the premixing chamber 2, which makes the flow rate of air supplied to the premixing chamber 2 uniform.

6 is a flame hole made of a punched plate or wire mesh, etc.;
is a flame holding part formed around the flame hole 6 and fixing the flame hole 6 to the premixing chamber 2. 7' is a secondary air guide cylinder extending concentrically from the vicinity of the flame hole 6, and 7# is an opening A provided near the flame hole 6. 8 is a secondary air passage provided concentrically around the outer periphery of the premixing chamber 2.

8' is an opening B provided outside the other end of the secondary air guide cylinder 7'.
It is. Reference numeral 9 denotes a porous rectifier plate provided in the secondary air passage 8, which equalizes the flow velocity of the secondary air. 9' is a cylindrical burner case provided around the outer periphery of the secondary air passage 8. IO is a long combustion chamber that communicates with the secondary air passage 8 and is provided on the downstream side of the flame hole 6, and 11 is a water-cooled wall formed around the combustion chamber IO. Reference numeral 12 denotes a constriction portion provided to the secondary air passage 8 on the downstream side of the flame hole 6. 13 is a flame formed downstream of the flame hole 6, and 14 is an ignition means. 1
A tertiary air passage 5 passes through the center of the flame hole 6, has one end extending toward the combustion chamber 10, and the other end is a tertiary air inlet provided approximately in the middle of the premixing chamber 2. 16 to secondary air passage q
It is connected to.

In the above configuration, fuel gas is ejected from the combustion nozzle 3 into the premixing chamber 2, and at the same time, air that has passed through the perforated plate 5 and becomes almost uniform enters the premixing chamber 2 due to the operation of the blowing means 1, and the fuel gas is and flows to the flame hole side. Other air passes through a porous baffle plate 9 in the secondary air passage 8 and is supplied separately from the opening A7' and the opening B8' of the secondary air guide tube 7'. Further, from the secondary air passage 8 to the tertiary air inlet 1
6 and flows to the tertiary air port 15. Now, the mixture of fuel gas and air ejected from the flame hole 6 becomes a flame 13 by the ignition means 14. At this time, the air from the secondary air passage 8 is forced into the flame 13 by the throttle part 12 of the opening B8'.
The air is supplied to the outer periphery of the air and can be used as secondary air to promote combustion. Further, tertiary air is supplied from the tertiary air passage 15 to the center of the premixture, and a flame 16 is formed downstream of the center of the flame hole 6 along the flow of the tertiary air.

By supplying air into and out of the premix in this manner, the contact area between the fuel and air is increased, and stable combustion without the generation of Co or soot can be achieved.

The secondary air stretches the flow of the premixture in the combustion chamber 10 and creates an air layer near the inner wall of the combustion chamber 10, so even if the flame 13 becomes long, no soot is generated due to lack of air, resulting in stable combustion. can be obtained. or,
Since a long flame 13 is formed in the combustion chamber 10, the combustion chamber l
The inside of O can be kept almost thermally uniform. Note that the flame length can be adjusted by increasing or decreasing the amount of air 1 supplied into the premixing chamber 2 or the amount of air from the tertiary air passage 15.

Also, a part of the total amount of air is supplied into the premixed air from the tertiary air passage 15 extending from the flame hole 6, and the secondary air is supplied from the opening A7'' and the opening B8' of the secondary air guide tube 7'. By dividing and supplying air, the secondary air flow rate near the flame hole 6 can be set to a small value, so the combustion reaction near the flame hole 16 becomes relatively gentle.Therefore, the total air amount is relatively low. Even if there is a large amount of air, the flame 13 is not disturbed by the secondary air, and combustion can be performed with low noise.

Effects of the Invention As described above, according to the combustion apparatus of the present invention, the following effects can be obtained.

(1) It is possible to form a stable long flame without producing Co or soot, and it is possible to obtain a columnar combustion device with a long heating surface with small temperature difference, which has a wide range of uses such as space heating, hot water supply, and drying. .

(2) Since air is supplied separately from the inside and outside to the mixture, the reaction is gentle and stable combustion with little noise can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a combustion device according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view of a burner portion of a conventional combustion device. ! ...Blower means, 2...Premixing chamber, 3
...Fuel nozzle, 6... Flame hole, 7'.
...Secondary air guide tube, 7''...Opening A
, 15... Tertiary air passage.

Claims (1)

[Claims] A premixing chamber for mixing fuel and air is provided on the downstream side of the blowing means, a fuel nozzle is provided on the upstream side of the premixing chamber, a flame hole is provided on the downstream side of the premixing chamber, and a flame hole is provided in the vicinity of the flame hole. A secondary air guide tube extends concentrically with the flame hole toward the downstream side,
An opening is provided in the secondary air guide tube near the flame hole, the other end is open, and a tertiary air passage is provided extending from the premixing chamber through the center of the flame hole, and the premixing chamber is 2 installed around
A combustion device in which a secondary air passage and the tertiary air passage communicate with each other.