JPH0311211A - Combustion equipment - Google Patents

Abstract

PURPOSE:To form a long and stable flame and enable a long heating surface with a small temperature difference to be obtained by mixing a fuel and the air in a premixing chamber by ventilation means and a fuel nozzle, blowing out a resultant mixture from flame holes into a combustion chamber and igniting a resultant mixture to form a flame and compulsorily supplying the air from a secondary air path through a constricted part to the circumference of the flame. CONSTITUTION:A fuel gas is blown out into a premixing chamber 2 from a fuel nozzle 2. At the same time, the air which has passed a perforated panel 5 to be made approximately uniform by the operation of ventilation means 1 enters the premixing chamber 2 and is mixed with the fuel gas to flow toward a flame 6. The other air passes a straightening panel 9 with many holes in a secondary air path 8 and a restriction 12 and flows toward a combustion chamber 10. The mixed gas of the fuel gas and the air blown out from flame holes 6 is made a flame 13 by ignition means 14. At this time, the air from the secondary air path 8 is compulsorily supplied to the circumference of the flame 13 via the restriction 12. This extends the flow of the premixed gas in the combustion chamber 10, enabling the inside of the combustion chamber 10 to be thermally maintained approximately uniform.

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 Conventionally, this type of combustion apparatus has an air swirling section 23 in a nozzle section 22 in a cylindrical combustion chamber 21, as shown in FIG. 2, and burns the fuel jetted from the nozzle 22 by vigorously mixing it with air. In many cases, there are pre-mixing type diffusion combustors, or some air is premixed and ejected from a nozzle, and air for diffusion combustion is supplied around it. The aim has been to burn a mixture of the two. In other words, it is undesirable for the flame to be long;
If it were to last too long, it would generate 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 made longer, its length will be limited by the problem of soot or cobalt. According to experiments, a length of 20 to 25C11 is the limit.

The present invention is intended to solve such conventional problems, and aims to form a long stable flame, which was previously considered impossible, and to obtain a long heating surface with little temperature difference.

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 and air downstream of the blowing means, and a fuel nozzle located upstream of the premixing chamber. a flame hole is provided on the downstream side of the premixing chamber, a secondary air passage is provided concentrically on the outer periphery of the premixing chamber, and a long air passage communicates with the secondary air passage downstream of the flame hole. A combustion chamber is provided, and the two on the downstream side of the flame hole are
The structure is such that a constriction section is provided to the next air passage.

Operation According to the above-described configuration, the fuel and air are mixed in the premixing chamber by the operation of the blowing means and the fuel nozzle, and are ejected from the flame hole into the combustion chamber, and a flame is formed by the ignition means. At the same time, air from the secondary air passage is forcibly supplied to the outer periphery of the flame by the constriction section, and becomes secondary air for combustion. Furthermore, this secondary air stretches the flow of the premixing chamber within the combustion chamber and forms a long, stable flame within the combustion chamber, thereby making it possible to maintain substantially thermal uniformity within the combustion chamber.

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

In FIG. 1, ■ indicates a blowing means such as an axial fan, and the broken line arrow indicates air. 2 is a substantially cylindrical premixing chamber;
The fuel (gas) from the fuel pipe 4 is fed into the premixing chamber 2 on the upstream side.
[14 Nozzle 3 is facing toward the inside]. 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. 8 is a secondary air passage provided concentrically around the outer periphery of the premixing chamber 2. 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.

10 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 10. 12 is a secondary air passage 8 on the downstream side of the flame hole 6
It is a constriction section provided in the. 13 is a flame formed downstream of the flame hole 6, and 14 is an ignition means.

In the above configuration, fuel gas is ejected from the fuel nozzle 2 into the premixing chamber 2, and at the same time, air that has passed through the perforated plate 5 and becomes almost uniform due to the operation of the blowing means 1 enters the premixing chamber 2, and the fuel gas is and flows to the flame 6 side. 1. Other air passes through the porous rectifier plate 9 in the secondary air passage 8, passes through the throttle section 12, and flows toward the combustion chamber 10 side. Now, flame hole 6
The mixture of fuel gas and air ejected from the ignition means 14
The result is flame 13. At this time, air from the secondary air passage 8 is forcibly supplied to the outer periphery of the flame by the throttle section 12, and can promote combustion as secondary air. In addition, this secondary air stretches the flow of the premixture in the combustion chamber IO and creates an air layer near the inner wall of the combustion chamber 10, so even if the flame 13 becomes long, there is no generation of soot due to lack of air, and the flame is stable. You can get combustion. Furthermore, since a long flame 13 is formed within the combustion chamber 10, the inside of the combustion chamber 10 can be kept thermally almost uniform. Note that the flame length can be adjusted by increasing or decreasing the amount of air supplied into the premixing chamber 2.

Effects of the Invention As described above, according to the combustion apparatus of the present invention, the following effects can be obtained. In other words, it is possible to form a long, stable flame without producing 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. .

[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. 1... Air blowing means, 2... Premixing chamber, 3
...Fuel nozzle, 6... Flame hole, 8...
...Secondary air passage, 10... Combustion chamber, 12
...Aperture section.

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 on the downstream side of the premixing chamber. A secondary air passage is provided concentrically on the outer periphery, a long combustion chamber is provided downstream of the flame hole in communication with the secondary air passage, and a throttle portion is provided in the secondary air passage downstream of the flame hole. combustion equipment.