JPH0217773B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to an all-primary premixed gas burner for a household water heater, and the present invention relates to an all-primary premixed gas burner for a household water heater. The present invention relates to an all-primary premixed gas burner for a domestic water heater that adopts an all-primary premixing method in which all amounts of air are mixed with fuel gas in advance, and forcibly mixes the air and fuel gas with a blower.

(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.

In this Bunsen burner, part of the combustion air (for example, about half of the amount of air required for complete combustion) is mixed in with the fuel gas when it is supplied to the burner, and the remaining combustion air is used for combustion. Air (for example, about half the amount of air required for complete combustion) is supplied as secondary air near the flame outlet, and sufficient air is taken in at that time to completely burn the fuel gas. .

Further, as an example of a premix combustion type water heater, there is a gas instantaneous water heater disclosed in Japanese Utility Model Application Publication No. 146250/1983.

When supplying fuel gas to the burner, this gas instantaneous water heater uses a blower outlet near the supply nozzle of the gas supply pipe to forcibly send combustion air through the blower to provide all necessary combustion air. This method takes in an amount of air during gas supply and sends it out to the flame port through a narrow mixer (all-primary premixing method).

In addition, multiple baffle plates are installed in the mixer part to disturb the flow of fuel gas and combustion air, and the flow lines of fuel gas and combustion air can be exchanged to prevent fuel gas. A structure configured to achieve turbulent mixing of combustion air and combustion air (for example, Japanese Utility Model Application No. 60-6933) has also been proposed.

(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. Air cannot be distributed, resulting in incomplete combustion and a very long flame. Therefore, the flame ports must be arranged at a certain distance from each other, and in order to ensure a certain amount of discharged gas to obtain a specified amount of heat, the size of the flame ports must be reduced to a certain limit or less. There is a drawback that it cannot be done.

Further, in this method, since the secondary air is dominated by diffusion, the flame inevitably becomes long to some extent during the combustion stage, making it difficult to shorten the flame. Therefore, it is necessary to provide a specified space between the flame port and the heat exchanger that is longer than the length of the flame, and this space must be secured as an essential space. However, there were some difficulties that became major obstacles in the process of achieving this goal.

On the other hand, in the case of a premix combustion method, especially in the case of a gas instantaneous water heater as 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 the distance between the supply nozzle and the flame nozzle, there is a problem in that the combustion air and fuel gas are insufficiently mixed, and in order to achieve good mixing, the mixer part must be made large. Must be.

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. Fuel gas is supplied without being sufficiently mixed with combustion air. As a result, it is very difficult to completely burn the fuel gas under stable conditions, and as mentioned above, the mixer section also has to be large.

In addition, if the mixer is configured with multiple baffle plates to achieve turbulent mixing of the fuel gas and combustion air, it is possible to obtain a sufficient mixing state of the fuel gas and combustion air. If this was attempted, the mixer portion etc. would become larger, which would result in the problem of making the entire water heater larger.

<Technical Problems> In view of the above-mentioned difficulties, the present invention improves the mixing state of fuel gas and combustion air, enables complete combustion in a stable state, and also reduces the size of the entire water heater. It was created with the aim of simplifying the structure and structure so that it could be provided at a low cost.

[Structure of the invention] (Means for solving the problem) Therefore, the present invention provides an air intake port 8 of the blower 2.
A plurality of gas supply nozzles 3 are arranged in a row in the part,
A gas combustion flame face plate 5 made of a porous plate is disposed beside the blower outlet 9 of the blower 2. and,
An impeller 7 is provided which can feed the air taken in from the air intake port 8 and the fuel gas ejected from the gas supply nozzle 3 toward the gas combustion flame face plate 5 while stirring the air in a turbulent state. The blower blade 25 of the impeller 7 has a plurality of cutting pieces 3 for mixing.
By providing the mixing section 30 consisting of one or a plurality of mixing holes 32, the above-mentioned difficulties can be solved.

(Function) Therefore, the fuel gas that is finely divided and uniformly ejected from the gas supply nozzles 3 arranged at the air intake port 8 of the blower 2 is taken in from the air intake port 8 by the impeller 7. It is stirred and mixed in a turbulent state with the combustion air.

At that time, the blower blade 25 of this impeller 7
By the mixing part 30 consisting of a plurality of cutting and raised pieces 31 for mixing or a plurality of holes 32 for mixing, a complex turbulent flow is generated as a whole, and further stirring and mixing are promoted.

The fuel gas and combustion air thus stirred and mixed are then fed toward the gas combustion flame face plate 5 and into the small flame holes 13 provided on the entire surface of the gas combustion flame face plate 5. A mixed gas of fuel gas and combustion air is uniformly delivered.

(Example) The present invention will be described below with reference to illustrated examples.

In the figure, 1 indicates a gas burner, and this gas burner 1 is composed of a blower 2, a plurality of gas supply nozzles 3, and a flame face plate 5 for gas combustion.

The blower 2, as shown in FIGS. 2 and 3,
The motor 6 and the driving force of this motor 6 are connected to the main shaft 2.
It consists of an impeller 7 that rotates by being transmitted to the casing 6, and a casing 10 that surrounds the impeller 7 and includes an air intake 8 and an air outlet 9.

A gas supply pipe 1 is installed at the air intake port 8.
A plurality of gas supply nozzles 3 are installed so as to be branched from the fuel gas supply nozzle 1, and the fuel gas ejection is subdivided.

The gas combustion flame face plate 5 is disposed above the air outlet 9 of the blower 2, and is formed by drilling small flame holes 13 at small intervals in a rectangular metal plate with a thickness of about 2 mm to 5 mm. There is. In addition, this gas combustion flame face plate 5
What is necessary is to ensure a length that allows the portion of the burner outlet hole 13 itself to be cooled by gas passing through the burner outlet hole 13. That is, without using a thick plate of about 2 mm to 5 mm, for example, a thin plate can be subjected to a drawing process called burring to form the small flame opening 13 with a cylinder vertically perpendicular to the thin plate. However, the length of this cylinder may be appropriately increased so that it can be cooled with gas (not shown), and other forms may be freely formed as appropriate.

As shown in FIGS. 2 and 3, the blower 2 has an impeller 7 formed by closing both ends of a large number of blowing blades 25 arranged along the circumferential direction with a main plate 27 and a side plate 28. A cross-flow fan is used in which the fuel gas and combustion air are configured to pass through the impeller 7 in a cross section perpendicular to the center of rotation. The impeller 7 is formed to have a length comparable to the left-right length of the gas combustion flame face plate 5, and is used for combustion with fuel gas that is segmented and ejected by a large number of gas supply nozzles 3. The air is stirred and mixed with air in a finely divided state, and further, this can be fed to the gas combustion flame face plate 5 in a finely divided state.

Further, the blowing blade 25 of the impeller 7 is formed with a mixing portion 30 that can sufficiently stir and mix the fuel gas and the combustion air. That is, as shown in FIG. 4, for example, this mixing section 30 has a plurality of approximately triangular mixing cut and raised pieces 31 formed (cut and raised) on the tip edge portion of the ventilation blade 25. The configuration may be such that the direction of the mixing cut-and-raised piece 31 is made different every 25 minutes so that fuel gas and combustion air can be sufficiently stirred and mixed, or as shown in FIG. A plurality of mixing holes 32 are provided in a substantially staggered manner on the entire surface of the 25 (arranged so that the mixing holes 32 of adjacent blower blades 25 do not coincide with each other in the rotational direction of the impeller 7), and the fuel gas and The structure may be such that the flow of the streamlines of the combustion air is changed so that the fuel gas and the combustion air can be sufficiently stirred and mixed, or a combination of these may be used. Note that the shape, number, size, arrangement position, etc. of the mixing cut-and-raised piece 31 and the mixing hole 32 can be freely set as appropriate, and the configuration of the mixing section 30 itself is also the same as the mixing cut-and-raised piece 31,
It is not limited to the mixing hole 32.
Further, the configuration of the blower 2 itself is not limited to the cross-flow fan as shown in the illustrated example.

Incidentally, between the blower outlet 9 and the gas combustion burner face plate 5, the combustion air and fuel gas sent from the blower outlet 9 are dispersed as appropriate while being stirred, and the mixed gas is dispersed between the blower outlet 9 and the gas combustion burner face plate 5. In order to uniformly feed the flame to all the flame opening holes 13 of the flame opening face plate 5, the dispersion small holes 1 are arranged.
Dispersion plate 14 made of a porous plate with a large number of holes 5 perforated.
may be disposed within the outer wall 16 in which the area from the air outlet 9 to the gas combustion flame face plate 5 is sealed.
In this case, the number of dispersion plates may be one, and the position, density, etc. of the dispersion holes 15 should be set appropriately so that the distance from the air outlet 9 to the gas combustion flame face plate 5 does not become wide. to ensure sufficient mixing and dispersion as described above.

The gas burner 1 formed in this manner is used by disposing the gas combustion flame face plate 5 at a small distance below the heat exchanger 17 in the domestic water heater B. In addition, the code 20 in the figure is the heat exchanger 1.
7 is a water pipe, and 21 is a fin for heat exchange.

[Effects of the Invention] Therefore, a plurality of gas supply nozzles 3 are arranged in a row at the air intake port 8 of the blower 2, and a gas combustion chamber formed of a porous plate is provided beside the blower outlet 9 of the blower 2. The air taken in from the air intake port 8 and the fuel gas ejected from the gas supply nozzle 3 are supplied toward the gas combustion flame face plate 5 while stirring them in a turbulent state. Since the impeller 7 is provided, the fuel gas can be divided into small pieces by the plurality of gas supply nozzles 3 and ejected uniformly toward the impeller 7, making it easier to mix with the combustion air taken in from the air intake port 8. Moreover, this fuel gas and combustion air can be stirred into a turbulent state by the impeller 7, and a sufficient mixed state can be obtained, and this sufficiently mixed gas can be directed toward the gas combustion flame face plate 5. can be supplied and complete combustion can be performed in a stable state. In addition, a well-mixed gas can be fed to the gas combustion flame face plate 5, and the gap between the gas combustion flame face plate 5 and the air outlet 9 can be narrowed, making the entire water heater smaller. This makes it possible to simplify the design and structure.

In addition, the blower blade 2 of the impeller 7 of the blower 2
5 is provided with a mixing part 30 made up of a plurality of mixing cut-and-raised pieces 31 or a mixing part 30 made up of a plurality of mixing holes 32, so that the fuel gas fed from the air intake port 8 and the combustion By changing the streamlines with the air, a more turbulent flow is ensured, and stirring can be performed reliably in this turbulent state, making it possible to obtain a well-mixed gas mixture. In addition, the mixing cut-and-raised piece 31 and the mixing hole 32 can be easily formed on the blower blade 25 of the impeller 7.

At this time, if the mixing cutting piece 31 and the mixing hole 32 are used together, the above-mentioned effect will be further improved.

By the way, 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 impeller 7, and when it reaches the blower outlet 9, it is mixed with a sufficiently mixed gas. After that, a stable combustion condition can be obtained. Furthermore, in this case, since a plurality of gas supply nozzles 3 are provided, the fuel gas is supplied in a more dispersed manner, and mixing is performed more reliably.

Next to the blower outlet 9 of the blower 2, a gas combustion flame face plate 5 made of a porous plate is placed.
As mentioned above, the completely mixed gas is uniformly sent to the small flame openings 13 of the gas combustion flame face plate 5.
The flame 18 from the gas combustion flame face plate 5 is completely combusted and becomes a short flame as shown in FIGS. 2 and 3. 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, the gas combustion flame face plate 5
Since air is not required on the surface of the flame outlet, there is no problem even if the flames overlap slightly by reducing the distance between the flame outlet holes 13, making it possible to arrange many flame outlets in a small area, making it compact. A large-capacity burner can be formed using this method, and miniaturization can be achieved in all aspects.

In addition, by using the blower 2 as a cross-flow fan,
The impeller 7 that is long in the axial direction can be used, and a large number of gas supply nozzles 3 can be arranged in the gas supply pipe 11, making it easier to subdivide the fuel gas jet and to separate the fuel gas and combustion air. The mixture can be stirred and mixed in the finely divided state, and further, it can be uniformly fed to the entire surface of the gas combustion flame face plate 5 in the finely divided state.

[Brief explanation of drawings]

The drawings illustrate the present invention; FIG. 1 is a partially cutaway perspective view, FIG. 2 is a longitudinal sectional front view, FIG. 3 is a longitudinal sectional side view, and FIGS. 4 and 5 show other embodiments. FIG. 2 is a perspective view of essential parts of the fan. B...Home water heater, 1...Gas burner,
2...Blower, 3...Gas supply nozzle, 5...
Flame face plate for gas combustion, 6...Motor, 7...Impeller, 8...Air intake, 9...Blower outlet, 10
...Casing, 11...Gas supply pipe, 13...
Flame opening small hole, 14... Dispersion plate, 15... Dispersion small hole,
16...Outer wall, 17...Heat exchanger, 18...Flame, 20...Water pipe, 21...Fin, 25...Blower blade, 26...Main shaft, 27...Main plate, 2
8...Side plate, 30...Mixing section, 31...Mixing cutting piece, 32...Mixing hole.

Claims (1)

[Scope of Claims] 1. A plurality of gas supply nozzles are arranged in a row at the air intake port of the blower, and at the air outlet of the blower,
A gas combustion flame face plate made of a porous plate is arranged, and the gas combustion flame is heated while stirring the air taken in from the air intake port and the fuel gas ejected from the gas supply nozzle into a turbulent state. A device for household use, characterized in that an impeller capable of feeding air toward a face plate is provided, and a mixing portion consisting of a plurality of mixing cut-and-raised pieces or a plurality of mixing holes is provided on the blower blade of the impeller. All primary premixed gas burners for water heaters. 2. An all-primary premixed gas burner for a domestic water heater according to claim 1, wherein the blower is a cross-flow fan.