JPH0217772B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Field of Application) This invention relates to a primary premixed gas burner for a domestic water heater, in which the entire amount of air necessary for combustion is supplied to the burner as fuel. The all-primary premixing method for domestic water heaters, which mixes gas with fuel gas in advance when supplying the gas, is used, and the air mixing is forcibly controlled by a centrifugal blower, thereby reducing the size and shortening of the flame. Regarding mixed gas burners.

(Prior Art) Conventionally, combustion methods using gas as fuel can be broadly classified into a diffusion combustion method and a premix combustion method.

Among the diffusion combustion type devices, there is a so-called Bunsen burner, which is commonly used in home water heaters.

This Bunsen burner uses some combustion air,
For example, around 40% to 50% of the fuel gas is mixed in beforehand when supplying fuel gas to the burner, but since this is insufficient for combustion, the remaining combustion air is used as secondary air near the flame nozzle. This method uses 100% air volume to completely burn the fuel gas by dispersing it through the turbulent flow created by the vortices.

In addition, the premix combustion method, for example,
There is a gas instantaneous water heater proposed in Publication No. 60-146250.

When supplying fuel gas to the burner, this gas instantaneous water heater has a blower outlet near the supply nozzle of the gas supply pipe, which forcibly sends in combustion air to provide all necessary combustion air. This is an all-primary premixing system in which air is taken in during gas supply and sent to the flame port through a narrow mixer.

(Problems to be solved by the invention) <Problems with the conventional technology> However, in the case of the diffusion combustion method, when the interval between the flame ports is narrowed, a portion where the flames overlap occurs, and there is no combustion in that portion. If the air is not used properly, incomplete combustion will occur, resulting in a very long flame. Therefore, the flame ports must be placed at a certain distance from each other, so in order to secure a certain amount of discharged gas to obtain the specified amount of heat, it is necessary to downsize the flame to a size below a certain limit. There are some problems that cannot be addressed.

In addition, in this method, since the secondary air is dominated by diffusion, it is inevitable that the flame will become longer to some extent during the combustion stage, and this will not lead to a shorter flame.
Therefore, it is necessary to maintain a certain distance between the flame port and the heat exchanger, which is equal to or longer than the length of the flame.
This space had to be reserved as an essential space, which posed a major obstacle to miniaturization.

On the other hand, in the case of a premix combustion method, especially in the case of the gas instantaneous water heater type mentioned above, the distance from the mixer to the flame opening is short, and the blower outlet is located near the supply nozzle of the gas supply pipe. Because of this, there is insufficient mixing of combustion air and fuel gas within the distance from the supply nozzle to the flame nozzle, and in order to achieve good mixing, the mixer part must be made larger. .

In reality, if we look at the conditions inside the mixer, the fuel gas from the supply nozzle flows straight toward the flame nozzle, so it is not sufficiently mixed with the combustion air. The fuel gas that has reached this point is supplied without being sufficiently mixed with combustion air. As a result, it is very difficult to achieve complete combustion under stable conditions, and as mentioned above, there is also the problem that the size of the mixer section increases.

<Technical Issues> In view of the above-mentioned problems, the present invention aims to achieve complete combustion in a stable state by simplifying the structure and dramatically improving the mixing of fuel gas and combustion air. It was created with the aim of making it possible to shorten the flame and downsize, and to provide it at a low cost.

[Structure of the Invention] (Means for Solving the Problems) This invention comprises a motor disposed approximately in the center, a fan that rotates around the motor by the driving force of the motor, and a fan disposed around the rotating side of the fan. The air intake part of the centrifugal blower has a side surface of the fan closed by a casing, and the air intake part of the centrifugal fan is closed by a casing. , a plurality of air intake ports are arranged in an arc shape in order in the rotational direction of the fan, and these air intake ports are provided with a plurality of gas supply ports branched from the gas supply pipe. A nozzle is arranged in each, a gas combustion flame face plate formed of a porous plate is arranged next to the blow outlet of the centrifugal blower, and between the blow outlet and the gas combustion flame face plate, The above-mentioned problems are solved by providing a mixer section formed of a porous plate that appropriately disperses the air and fuel gas sent out from the ventilation outlet while stirring and sends the mixed gas to the face plate. It is.

(Function) A plurality of gas supply nozzles are arranged upstream of the air intake part of the centrifugal blower, and at the blower outlet, the turbulence of the airflow caused by the fan of the centrifugal blower causes fuel gas and combustion air to be mixed. Ensure that sufficient mixing is carried out.

At that time, in the case of the air intake part of a centrifugal blower, the side of the fan is closed by a casing, and the casing has multiple air intake ports that are visible in the upstream direction of the fan's rotation. These air intake ports are arranged in a circular arc shape in order and are formed with openings, and a plurality of gas supply nozzles branched from a gas supply pipe are arranged in each of these air intake ports to supply fuel gas, respectively.

Then, since the air intake there is performed in the direction of rotation of the fan, a plurality of gas supply nozzles are arranged vertically with respect to the air intake direction, and the fuel gas taken in at each air intake port is The combustion air collides with the combustion air sucked in at the downstream air intake and the ejected fuel gas, creating a turbulent flow and being agitated and mixed.

The fuel gas and combustion air mixed in the air intake section of the centrifugal blower are sent by the centrifugal blower to a mixer section formed of a porous plate, and the mixer section Further, at the same time as mixing, a mixed gas of fuel gas and combustion air is uniformly sent to all the holes of the gas combustion flame face plate.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

That is, the reference numeral 1 shown in the figure is a gas burner, which is composed of a centrifugal blower 2, a plurality of gas supply nozzles 3, a mixer section 4, and a flame face plate 5 for gas combustion.

As shown in FIGS. 2 and 3, the centrifugal blower 2 includes a motor 6 disposed approximately in the center, and is rotated around the motor 6 by the driving force of the motor 6, and rotates in the direction of rotation. A fan 7 made of curved blades is surrounded by an air intake port 8 as an air intake portion on the rotating side of the fan 7, and an air outlet 9 is arranged in a direction close to the rotation of the fan 7. The fan is composed of a casing 10 having a substantially snail shape.

The air intake port 8 is closed on the side of the fan 7 by a casing 10, and is opened in the casing 10 by arranging a plurality of upstream ports sequentially in an arc shape in the direction of rotation of the fan 7. It is provided with holes upstream of the air intake portion, and in the illustrated example, five circular air intake ports 8 are arranged at appropriate intervals.

In this way, the centrifugal blower 2 and the gas supply nozzle 3
Since the motor 6 is located approximately in the center and sends gas in the centrifugal direction, the motor 6
Even if sparks are generated during the rotation of the fan 7, the fuel gas will never enter the motor 6 as long as the fan 7 is rotating, and there is no fear of ignition.

A plurality of gas supply nozzles 3 are formed by branching from the gas supply pipe 11, and one end portion of each of the gas supply nozzles 3 is inserted into each of the air intake ports 8. This gas supply nozzle 3 is
As shown in FIG. 4, an appropriate number of small nozzle holes 12 are drilled on the circumferential surface of the tip portion, and as shown in FIG.
The fuel gas is ejected from this nozzle small hole 12 in a radial direction. In this way, by opening the small nozzle hole 12 in the gas supply nozzle 3, the combustion air and the fuel gas can be mixed even better.

On the other hand, the flame outlet face plate 5 for gas combustion is connected to the centrifugal blower 2.
It is arranged above the air outlet 9 of the flame outlet 9, and is formed by drilling small holes 13 at small intervals in a rectangular metal plate having a thickness of about 2 mm to 5 mm. This gas combustion flame face plate 5
The length of the flame opening small hole 13 should be ensured so that the gas can be cooled by passing through the small hole 13 itself. In other words, even if you do not use a thick plate of about 2 mm to 5 mm, for example, although not shown in the drawing, you can use a flame outlet made by applying a drawing process called burring to a thin plate and having a cylinder perpendicular to the thin plate. Small hole 13
However, the length of this cylinder may be appropriately increased so that it can be cooled with gas, and the shape is not limited to this.

The combustion air and fuel gas sent out from the ventilation outlet 9 are dispersed as appropriate between the ventilation outlet 9 and the gas combustion flame port face plate 5 while stirring, and the mixed gas is mixed with the gas combustion flame port. A mixer unit 4 is arranged to uniformly feed the flame to all the small flame openings 13 of the face plate 5.

This mixer section 4 is made up of a suitable number of dispersion plates 14 made of porous plates with a large number of small dispersion holes 15. , and is formed within an outer wall 16 that seals the area from the air outlet 9 to the gas combustion flame face plate 5. In this case, any number of dispersion plates 14 may be used, but even if there is only one dispersion plate 14, the above-mentioned mixing and dispersion can be carried out sufficiently by appropriately changing the position, density, etc. of the small dispersion holes 15. In other words, the structure of the mixer section 4 is not limited to that described above as long as it is small.

The gas burner 1 formed in this way is used by being arranged so that the gas combustion flame face plate 5 is positioned below the heat exchanger 17 in the domestic water heater B with a small interval therebetween. In addition, the reference numeral 20 in the figure is a water tube of the heat exchanger 17, and 21 is a fin for heat exchange.

[Effects of the Invention] The present invention configured as described above has a motor 6 disposed approximately in the center, a fan 7 that rotates around the motor 6 by the driving force of the motor 6, and a fan 7 disposed on the rotating side of the fan 7. The air intake part of the centrifugal blower 2 has a centrifugal blower 2 made of a Shirodskov fan having an air intake part. A plurality of air intake ports 8 are formed in the casing 10 by opening and arranging them sequentially in an arc shape in the direction of rotation of the fan 7, with the upstream side facing upstream. Since it is a centrifugal blower 2, by disposing a plurality of branched gas supply nozzles 3 in each, even if the gas supply nozzle 3 is disposed upstream of the air intake part, it will not work while the motor 6 is rotating. There is no fear of the fuel gas igniting due to the sparks generated.

Moreover, as mentioned above, there are multiple air intake ports 8.
are arranged in an arc shape in order in the direction of rotation of the fan 7, with the upstream side being known, and these air intake ports 8,
Since a plurality of gas supply nozzles 3 branched from the gas supply pipe 11 are arranged to supply fuel gas respectively, the air intake there is performed in the direction of rotation of the fan, so that the air intake direction is A plurality of gas supply nozzles 3 are arranged vertically, and the fuel gas and combustion air taken in through each air intake port 8 are sucked into the downstream air intake port 8. The combustion air collides with the ejected fuel gas, creating a turbulent flow and stirring and mixing. Therefore, while the fuel gas reaches the blower outlet 9, all the air necessary for combustion and the fuel gas are stirred and mixed by the turbulent flow when the fuel gas collides with the fan 7, and reaches the blower outlet 9. When this occurs, the gas mixture is sufficiently mixed, and incomplete combustion cannot occur in subsequent combustion.

Then, a gas combustion flame face plate 5 made of a porous plate is placed across the air outlet 9 of the centrifugal blower 2,
Between the blower outlet 9 and the gas combustion flame face plate 5, there is a porous plate that disperses the air and fuel gas sent out from the blower outlet 9 as appropriate while stirring, and sends the mixed gas to the face plate 5. By providing the mixer section 4 formed of Since the flame 18 from the gas combustion flame face plate 5 is sent uniformly to the small holes 13, the flame 18 is completely combusted and reaches the second
As shown in Fig. 3, the flame becomes short. As a result, the distance between the heat exchanger 17 and the gas combustion flame face plate 5 can be very small, so that the space for the flame, which was conventionally indispensable, can be made extremely small. Moreover, since the mixed gas itself is completely mixed, no air is required on the surface of the gas combustion flame port face plate 5, so even if the spacing between the flame port holes 13 is made small and the flames overlap slightly, there will be no problem. It is possible to arrange many flame ports in a small area without any problems, and it is possible to form a small and large-capacity burner. Furthermore, since the mixed gas is almost completely mixed in advance, it is sufficient to shorten the distance through which the mixed gas passes through the mixer section 4, so that miniaturization can be achieved in all aspects.

As explained above, according to the present invention, by dramatically improving the mixing of fuel gas and combustion air, complete combustion can be achieved in a stable state, resulting in shorter flame length and smaller size. Furthermore, the burner has a simplified structure and can be provided at low cost, providing various effects that are far superior to those of conventional burners.

[Brief explanation of drawings]

The drawings show one embodiment of the invention.
The figure is a partially cutaway perspective view, Figure 2 is a front sectional view, Figure 3 is a side sectional view, Figure 4 is an enlarged sectional view of the gas supply nozzle, and Figure 5 shows the gas ejection state in Figure 4. It is a sectional view along the arrow line. B...Home water heater, 1...Gas burner,
2...Centrifugal blower, 3...Gas supply nozzle, 4
...Mixer part, 5...Flame face plate for gas combustion, 6
... Motor, 7 ... Fan, 8 ... Air intake, 9 ... Air outlet, 10 ... Casing, 11
...Gas supply pipe, 12...Nozzle small hole, 13...
Flame opening small hole, 14... Dispersion plate, 15... Dispersion small hole,
16...Outer wall, 17...Heat exchanger, 18...Flame.

Claims (1)

[Claims] 1. It has a centrifugal blower consisting of a Sirotskov fan, which has a motor arranged approximately in the center, a fan that rotates around the motor by the driving force of the motor, and an air intake part arranged on the side of the rotation of the fan,
The air intake part of this centrifugal blower is constructed by closing the side of the fan with a casing, and in that casing, multiple air intake ports are arranged in an arc shape in order in the direction of rotation of the fan. These air intakes are formed by opening and arranging them side by side.
A plurality of gas supply nozzles branched from the gas supply pipe are respectively arranged, and a gas combustion flame face plate made of a porous plate is arranged next to the air outlet of the centrifugal blower. and a gas combustion flame face plate, there is a mixer section formed of a porous plate that appropriately disperses the air and fuel gas sent out from the air outlet while stirring and sends the mixed gas to the face plate. An all-primary premixed gas burner for a home water heater, characterized by being provided with.