JPH0432284B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a premix burner of entirely new construction.

For example, in order to make household gas water heaters and gas space heaters more compact, it is necessary to develop burners capable of high-load combustion.

By the way, as a high-load combustion burner that uses city gas with a relatively low supply pressure, a typical mixed blast burner is one in which combustion air is jetted out at a relatively high pressure and fuel gas is sucked and mixed and combusted.
Conventional mixed blast burners require a high jetting pressure of combustion air, which has the drawbacks of large fans, high noise levels, and the tendency to cause flashbacks. .

Therefore, it is possible to pre-mix the low-pressure supply gas and the low-pressure supply air and perform short flame combustion, but in order to do so, it is necessary to ensure that the gas and air are mixed very well, and
It is necessary to solve the technical problem of being able to reliably prevent overheating of the burner combustion section due to low pressure supply and short flame combustion.

An object of the present invention is to solve the above problems and provide a compact premix blast burner that is capable of high-load combustion while using relatively low-pressure combustion air.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, embodiments of a pre-mixing blast burner according to the present invention will be described below with reference to the drawings.

As shown in the conceptual diagram of FIG. 1, a blower (not shown) or the like is used to blow approximately
A combustion air introduction pipe 2 to which combustion air is forcibly supplied at a relatively low supply pressure of 20 mm ² O is connected. Further, a bottomed cylindrical inner case 3 with a flared tip for flame formation is placed inside the outer case 1, with the tip opening 3a of the inner case 3 and the opening 1a of the outer case 1 facing upward, The bottom side of the peripheral wall of the inner case 3 is inserted so as to face the connection between the combustion air introduction pipe 2 and the outer case 1. Furthermore, a low-pressure fuel gas introduction pipe 4 is connected to the bottom of the inner case 3, and a gas introduction hole 4a having a diameter smaller than the inner diameter of the gas introduction pipe 4 is formed at the tip of the gas introduction pipe 4. A gas dispersion plate 5 is disposed at the inner bottom of the inner case 3 so as to face each other directly above.

A plurality of primary combustion air introduction holes 6 are formed around the gas introduction hole 4a at the bottom of the inner case 3, and a plurality of primary combustion air introduction holes 6 are formed at the connection portion between the combustion air introduction pipe 2 and the outer case 1. A plurality of combustion secondary air introduction slits (holes may also be used) 7 are formed in the widening portion around the tip opening 3a of the inner case 3 that does not face each other.

That is, the combustion air introduction pipe 2 is connected to the lower part of the peripheral wall of the outer case 1, and the primary air introduction holes 6...
and secondary air introduction slit (hole may also be used) 7...
By forming these at the bottom of the inner case 3 that does not face the connection between the combustion air introduction pipe 2 and the outer case 1, and at the widening part around the tip opening 3a of the inner case 3, the connection part The combustion air is transferred to the primary air introduction hole 6 without being affected by the flow of combustion air supplied into the outer case 1 from the
...and secondary air introduction slit (hole may also be used) 7...
Each of them is designed to uniformly supply the entire area inside the inner case 3. Moreover, inner case 3
is inserted into the outer case 1 with the bottom side of the peripheral wall of the inner case 3 facing the connection part, thereby making the vertical length of the burner compact. . The total opening area of the primary air introduction holes 6 is set to be relatively small so that the mixing ratio of the supplied primary air and fuel gas does not reach the flammable range.
The total opening area of the secondary air introduction slits or holes 7 is made relatively large so that a sufficient amount of air can be supplied for sufficient combustion.

Further, a very narrow annular gap 8 is provided between the inner circumferential surface of the outer case 1 and the tip edge of the inner case 3, and the air ejected through the annular gap 8 causes the flame ejection opening of the outer case 1 to be closed. It is configured to cool the constricted end portion around 1a, thereby preventing that portion from overheating. 9 in the figure is an igniter.

In the pre-mixing blast burner having the above configuration, since the diameter of the gas introduction hole 4a is smaller than the inner diameter of the gas introduction pipe 4, the gas ejected from the gas introduction hole 4a has a faster flow rate and passes through the dispersion plate. 5, and as a result, turbulence is effectively promoted and the flow velocity is reduced, and the air is dispersed in the radial direction along the bottom surface of the inner case 3, and introduced from the primary air introduction holes 6... The primary air collides with the gas flow in a state almost perpendicular to the gas flow, so they mix extremely well. However, since the amount of primary air is small, the mixture does not burn and the inner case 3 expands. The air flows toward the opening 3a, and collides with a large amount of secondary air introduced from the substantially lateral direction through the secondary air introduction slits or holes 7, inside the opening 3a. However, the two are mixed well and burnt.

In this way, by ejecting the combustion gas from the gas introduction hole 4a whose diameter is smaller than the inner diameter of the gas introduction pipe 4 and colliding with the dispersion plate 5, the combustion air and the fuel gas are mixed extremely well. This is combined with the fact that both supply pressures are low and the momentum of the fuel gas toward the opening 3a of the inner case 3 is reduced.
Very good short-fire, high-load combustion can be achieved, and yellow chips, which tend to occur with premix burners, are less likely to occur.

In addition, the entire inner case 3 for flame formation is inserted into the outer case 1 through which combustion air flows so that it is constantly cooled, and the bottom of the inner case 3 is Combined with the fact that the burner is prevented from burning, overheating of the burner can be extremely effectively prevented, and the entire burner can be constructed from an inexpensive metal material such as sheet metal.

FIG. 2 shows a specific embodiment of a premix blast burner according to the invention.

Its basic configuration is almost the same as the above-mentioned embodiment, but additional explanations include the fact that the burner is almost entirely made of sheet metal, and that there is a rectifying annular structure between the combustion air introduction pipe 2 and the outer case 1. For example, a space 10 is formed and a frame monitoring window 11 is provided.

In summary, the characteristic configuration of the premix blast burner according to the present invention is that a combustion air introduction pipe is connected to the peripheral wall of a bottomed cylindrical outer case equipped with a flame ejection opening, and a flame is formed inside the outer case. A cylindrical inner case with a bottom for use with the inner case, with the tip opening of the inner case and the opening of the outer case facing the same direction, and the bottom side of the inner case being connected to the combustion air introduction pipe and the outer case. a fuel gas introduction pipe is connected to the bottom of the inner case, and a gas introduction hole having a smaller diameter than the inner diameter of the gas introduction pipe is formed at the tip of the gas introduction pipe;
A gas distribution plate is disposed in the inner case in a state facing the gas introduction hole, and a primary combustion air introduction hole of relatively small area is bored around the gas introduction hole at the bottom of the inner case. In addition, a secondary combustion air introduction slit or hole having a relatively large area is formed around a tip opening of the inner case that does not face the connection between the combustion air introduction pipe and the outer case. At the point.

The functions and effects exhibited by the above characteristic configuration are as follows.

That is, as detailed in the description of the embodiment, the inner case is inserted into the outer case with the bottom side of the peripheral wall facing the connection between the combustion air introduction pipe and the outer case. This allows the burner to be constructed more compactly.

Further, by forming the primary air introduction hole and the secondary air introduction slit (holes may be used) respectively in the bottom part of the inner case that does not face the connection part and in the widening part around the tip opening of the inner case, The primary air and secondary air for combustion are supplied through the primary air introduction hole and the secondary air introduction slit (holes may also be used), respectively, without being affected by the flow of the combustion air supplied from the connection part into the outer case. From this, it is arranged to uniformly supply the entire area inside the inner case.

In addition, by ejecting the combustion gas from the gas introduction hole whose diameter is smaller than the inner diameter of the gas introduction pipe and colliding with the dispersion plate, the gas ejected from the gas introduction hole is Since the diameter is smaller than the inner diameter, the flow velocity is increased and collided with the dispersion plate, which effectively promotes turbulence and reduces the flow velocity, causing the flow to flow in the radial direction along the bottom surface of the inner case. The primary air that is dispersed and flowed and uniformly introduced from the primary air introduction hole collides with the gas flow in a state almost perpendicular to the gas flow, resulting in extremely good mixing. However, since the primary air is small, the mixing The air does not burn but flows toward the tip opening of the inner case, and collides with the secondary air that is uniformly introduced in large quantities from the substantially lateral direction through the secondary air introduction slit or hole, and both of them still Mix well.

In this way, the primary air and secondary air for combustion are uniformly supplied to the entire area inside the inner case, and the primary air and secondary air for combustion and the combustion gas are extremely distributed within the inner case. By achieving good collision mixing and reducing the momentum of the fuel gas toward the combustion section, it has become possible to perform very good short flame combustion.

In addition, the entire inner case for flame formation was inserted into the outer case where the combustion air flows to ensure constant cooling, and the amount of primary air was reduced to prevent combustion from occurring at the bottom of the inner case. As a result, overheating of the burner can be prevented extremely effectively. Also,
This made it possible to construct the entire burner from inexpensive metal materials such as sheet metal.

[Brief explanation of drawings]

The drawings show an embodiment of the pre-mixing blast burner according to the present invention, with FIG. 1 being a schematic sectional view and FIG. 2 being a sectional view showing a specific configuration. 1...Outer case, 1a...Flame jetting opening,
2...Combustion air introduction pipe, 3...Inner case, 3
a...Tip opening of inner case 2, 4...Combustion gas introduction pipe, 4a...Gas introduction hole, 5...Gas distribution plate, 6...Primary air introduction hole, 7...Secondary air introduction slit or Hole.

Claims (1)

[Claims] 1 Connect the combustion air introduction pipe 2 to the peripheral wall of the bottomed cylindrical outer case 1 equipped with the flame jetting opening 1a,
A bottomed cylindrical inner case 3 for flame formation is placed inside the outer case 1, with the tip opening 3a of the inner case 3 and the opening 1a of the outer case 1 facing the same direction, and the inner case 3 The bottom side of the combustion air introduction pipe 2 is inserted into the connection part between the combustion air introduction pipe 2 and the outer case 1 so as to face it, and the fuel gas introduction pipe 4 is connected to the bottom of the inner case 3. A gas introduction hole 4a having a diameter smaller than the inner diameter of the gas introduction tube 4 is formed at the tip of the gas introduction tube 4, and the gas introduction hole 4a
A gas dispersion plate 5 is disposed in the inner case 3 so as to face the gas distribution plate 5, and primary air introduction holes 6 for combustion having a relatively small area are provided around the gas introduction hole 4a at the bottom of the inner case 3. and the combustion air introduction pipe 2 and the outer case 1.
A pre-mixed blast burner characterized in that a comparatively large-area combustion secondary air introduction slit or hole 7 is formed around the tip opening 3a of the inner case 3 that does not face the connection part with the .