KR101055984B1 - Premix Burner - Google Patents

Abstract

The present invention, the gas valve is opened and closed for gas supply; An air-gas mixing chamber in which air supplied from a blower and gas supplied through the gas valve are mixed; A flame forming unit combusting the air-gas mixer supplied from the air-gas mixing chamber; And a premixed gas burner comprising a plurality of subpremixed burners each independently having a nozzle chamber for supplying gas supplied through the gas valve to an air-gas mixing chamber, wherein each of the subpremixed burners is provided from the blower. The air-gas mixing chamber is characterized in that the air supply valve portion is further provided so that the supply or blocking of air is made independently.

In the premixed burner according to the present invention configured as described above, it is possible to maintain a high combustion efficiency even at a low output because the turndown ratio is improved by providing a plurality of sub premixed burners and the supply of excess air is blocked. Emissions are also reduced.

Sub premix burner, turndown ratio, thermal efficiency, air supply valve, excess air

Description

Premix burner

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a premix burner for use in a gas boiler, and more particularly, to a premix burner having a high turndown ratio, a high thermal efficiency even at a low output, and a reduction in nitrogen oxide emissions.

In general, a gas boiler includes a Bunsen burner and a premix burner as burners used to burn fuel gas.

The Bunsen burner is flame-formed by mixing the primary air, which is part of the air supplied from the blower 11, with the gas injected from the fuel gas injection nozzle 12, as schematically illustrated in the accompanying drawings FIGS. 1A and 1B. In addition to being supplied to the part 13, the secondary air, which is another part of the air, is supplied to the space between the flame forming parts 13 to constitute a structure that induces complete combustion of the fuel gas. Such Bunsen burners are widely used due to their simple structure and low cost, but have a low turn-down ratio, that is, a ratio of maximum gas consumption to minimum gas consumption, and a large amount of excess air, resulting in low thermal efficiency and harmful nitrogen. There is a problem that a large amount of oxide emissions.

In order to improve the characteristics of the conventional Bunsen burner, as shown in FIG. 2, a plurality of gas supply pipes 14a and 14b are provided, and a valve 15a and 15b are provided in each of the gas supply pipes 14a and 14b. There is a Bunsen burner. This has the advantage that it is possible to increase the turndown ratio by opening only the valves 15a and 15b of the required part according to the degree of desired output. However, even in this improved Bunsen burner, the emission of nitrogen oxides is not reduced, and as the air is supplied to all the flame forming portions 13a and 13b regardless of whether the valves 15a and 15b are opened, a low output is obtained. Even if required, even if the gas supply pipe of the unnecessary portion is locked, there is a problem that the thermal efficiency is lowered due to the excess air amount.

Meanwhile, as illustrated in FIG. 3, the premix burner has a structure in which the air sucked by the blower 21 is mixed with the fuel in advance to combust it, thereby reducing nitrogen oxide emissions and lowering the excess air ratio, thereby improving thermal efficiency. It is. However, such a premixed burner also has a limitation in increasing the turndown ratio, and the material of the burner also has a disadvantage in that the manufacturing cost is high because it is made of metal fiber or ceramic.

Figure 4 illustrates an improved premix burner to increase the turndown ratio, the gas inlet pipe 31 is provided with a gas amount adjusting orifice 32 to adjust the gas supply amount, the air intake pipe 33 Consists of adjustable air volume control orifice 34 is installed. However, such a premixed burner requires a driving device for adjusting the opening amount of the orifices (32, 34), there is a problem that the structure is complicated, and the price is also expensive.

5A and 5B show another example of the premix burner. This premix burner has a structure in which one blower 41 is provided with a plurality of gas valves 42a and 42a 'and a plurality of air-gas mixing chambers 42b and 42b'. That is, the premix burner itself is composed of a plurality of sub premix burners 42 and 42 ', and each of the sub premix burners 42 and 42' is provided with air-gas mixing chambers 42b and 42b '. have. Therefore, when high power is required, combustion occurs in all sub premix burners 42 and 42 ', and when only low power is required, combustion occurs in only some sub premix burners 42 and 42'. . The premix burner having such a structure has an advantage that the structure is simple and cheaper than the premix burner of FIG. 4 described above, while reducing the amount of nitrogen oxides and increasing the turndown ratio. However, since this premixed burner is continuously supplied with air even in a sub premixed burner in which combustion does not occur in the situation of low power, there exists a problem that thermal efficiency falls by excess air supply.

The present invention is to improve the problems of the conventional Bunsen burner and the pre-mixed burner as described above, to provide a pre-mixed burner having a high turndown ratio, high thermal efficiency at low power, and also reduces the emission of nitrogen oxides Has its purpose.

The present invention for achieving the above object, the gas valve is opened and closed for gas supply; An air-gas mixing chamber in which air supplied from a blower and gas supplied through the gas valve are mixed; A flame forming unit combusting the air-gas mixer supplied from the air-gas mixing chamber; And a premixed gas burner comprising a plurality of subpremixed burners each independently having a nozzle chamber for supplying gas supplied through the gas valve to an air-gas mixing chamber, wherein each of the subpremixed burners is provided from the blower. Disclosed is a pre-mix burner, characterized in that the air supply valve portion is further provided to independently supply or block air to the air-gas mixing chamber.

Here, the air supply valve portion may be made of a structure that is opened and closed by the pressure variation in the nozzle chamber.

In particular, the air supply valve unit, an air supply valve having a valve body that operates to supply or shut off air from the blower to the air-gas mixing chamber, and a valve seat on which the valve body is seated, and the elastic force in the direction in which the air supply valve is closed. It may be made of an elastic member to be given, including a diaphragm that is expanded and contracted according to the pressure variation inside the nozzle chamber to open and close the air supply valve.

In addition, the air supply valve further comprises a support plate for supporting the valve body on one side of the diaphragm and a support for connecting the support plate to the valve body, the elastic member is made of a structure provided between the support plate and the valve seat Can be.

In addition, the air supply valve portion may be configured to be opened and closed by the solenoid.

In the premixed burner according to the present invention configured as described above, it is possible to maintain a high combustion efficiency even at a low output because the turndown ratio is improved by providing a plurality of sub premixed burners and the supply of excess air is blocked. Emissions are also reduced.

Hereinafter, the configuration and operation of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 6 is a front view schematically showing a premix burner according to an embodiment of the present invention, and FIGS. 7A and 7B are side cross-sectional views illustrating an operating state of an air supply valve unit in the premix burner of FIG. 6, respectively.

As shown in FIG. 6, the premix burner of the present embodiment includes a plurality of sub premix burners 110, 120, and 130, and the sub premix burners 110, 120, and 130 are connected to one common blower 140. Get air. The components of the premix burner of the present embodiment will be described in detail as follows.

Referring to FIG. 7A, there is shown one sub premix burner 120 connected to the blower 140. The sub premix burner 120 shown and the remaining sub premix burners 110 and 130 not shown in FIG. 7A are illustrated. All of the same structure, the illustrated sub pre-mix burner 120 is configured as follows.

That is, an air-gas mixing chamber 121 in which air and gas are mixed is formed inside the sub premix burner 120, and an air-gas mixing chamber 121 is formed at the upper end of the sub premix burner 120. It is provided with a flame forming section 122 in which the air-gas mixer supplied from the combustion chamber is burned. In addition, a gas valve 123 is provided at one side of the sub premix burner 120 to allow fuel gas supplied from an external gas supply source (not shown) to flow into the air-gas mixing chamber 121 or to block inflow. It is provided.

In addition, the nozzle chamber 124 for supplying the fuel gas supplied through the gas valve 123 to the air-gas mixing chamber 121 on the path from the gas valve 123 side to the air-gas mixing chamber 121. Is formed, and the nozzle chamber 124 is provided with a nozzle 124a for injecting fuel gas into the air-gas mixing chamber 121.

In addition, between the blower 140 and the path from the air-gas mixing chamber 121 to the nozzle chamber 124, the air is supplied or blocked from the blower 140 to the air-gas mixing chamber 121. The air supply valve part 125 is provided. This air supply valve part 125 is comprised from the air supply valve 125a, the elastic member 125b, and the diaphragm 125c.

That is, the air supply valve 125a includes a valve body 125aa that operates to supply or shut off air from the blower 140 to the air-gas mixing chamber 121, and a valve seat 125ab on which the valve body 125aa is seated. ) In addition, the elastic member 125b is an element for imparting an elastic force in a direction in which the air supply valve 125a is closed, and may be formed of a compression coil spring. In addition, the diaphragm 125c expands and contracts according to a pressure variation inside the nozzle chamber 124 to open and close the air supply valve 125a.

In particular, the air supply valve 125a further includes a support plate 125ac for supporting the valve body 125aa on one side of the diaphragm 125c and a support 125ad for connecting the support plate 125ac to the valve body 125aa. The elastic member 125b is provided between the support plate 125ac and the valve seat 125ab.

Therefore, the air supply valve 125 is opened and closed by the pressure fluctuation of the nozzle chamber 124. When the gas valve 123 is opened, the pressure P1 in the nozzle chamber 124 is outside the nozzle chamber 124. By being higher than the inlet pressure P2 of the air-gas mixing chamber 121 located in the air supply valve 125a, air is introduced into the air-gas mixing chamber 121 from the blower 140.

That is, as shown in FIG. 7B, when the pressure of P1 becomes higher than P2 as the gas valve 123 is opened, the diaphragm 125c is extended to compress the elastic member 125b, and the diaphragm is supported by the support plate 125ac. The valve body 125aa of the air supply valve 125a supported by 125c is spaced apart from the valve seat 125ab to open the air supply valve 125a. Then, the air blown from the blower 140 is supplied to the air-gas mixing chamber 121 through the open air supply valve 125a, and the supplied air is injected from the nozzle 124a installed in the nozzle chamber 124. Mixing with the fuel gas is the combustion of the air-gas mixer in the flame forming unit 122.

On the other hand, when the gas valve 123 is closed, the pressure P1 in the nozzle chamber 124 becomes the same as the inlet pressure P2 of the air-gas mixing chamber 121, and thus, by the elastic restoring force of the elastic member 125b. The valve body 125aa of the air supply valve 125a is seated on the valve seat 125ab and the air supply valve 125a is closed. Accordingly, the air supply from the blower 140 to the air-gas mixing chamber 121 is blocked, so that the combustion of the air-gas mixer is no longer performed in the flame forming unit 122.

The air supply valve unit 125 is installed in the other sub premix burners 110 and 130, respectively, so that the air supplied from one blower 140 is independently supplied / blocked to the respective sub premix burners 110 and 120 and 130. . Therefore, it is possible to prevent the problem that the conventional excess air is lowered thermal efficiency.

The premix burner of the present invention includes a plurality of sub premix burners to improve the turndown ratio and cut off the supply of excess air, thereby maintaining high combustion efficiency even at a low output, and also reducing nitrogen oxide emissions.

On the other hand, the air supply valve unit 125 may be replaced by a solenoid valve in addition to the valve described in the above-described embodiment.

In the above described the present invention based on the preferred embodiment, the present invention is not limited to the above embodiment, various modifications by those skilled in the art within the scope of the technical idea of the present invention This is possible.

Figure 1a is a front cross-sectional view schematically showing a conventional Bunsen burner,

FIG. 1B is a plan view schematically illustrating the Bunsen burner of FIG. 1A;

2 is a plan view schematically showing another conventional Bunsen burner,

3 is a view schematically showing an example of a conventional premix burner,

4 is a view schematically showing another example of a conventional premix burner,

Figure 5a is a side cross-sectional view schematically showing another example of a conventional premix burner,

FIG. 5B is a front sectional view showing the sub-mixing burner in a premixed burner of FIG. 5A;

6 is a front view schematically showing a premix burner according to an embodiment of the present invention;

7A and 7B are side cross-sectional views each illustrating an operating state of the air supply valve unit in the premix burner of FIG. 6.

<Explanation of symbols for the main parts of the drawings>

110, 120, 130: sub premix burner 121: air-gas mixing chamber

122: flame forming portion 123: gas valve

124: nozzle chamber 124a: nozzle

125: air supply valve portion 125a: air supply valve

125aa: valve body 125ab: valve seat

125ac: support plate 125ad: support

125b: elastic member 125c: diaphragm

140: blower

Claims (5)

In the premix burner consisting of a plurality of sub premix burners, Each of the sub premix burners, An air-gas mixing chamber formed in the sub premix burner and mixing air and gas; A blower provided at a lower portion of the sub premix burner to supply air to the air-gas mixing chamber; A gas valve provided at one side of the sub premix burner to open and close to supply gas to the air-gas mixing chamber; A flame forming unit provided at an upper end of the sub premix burner to combust the air-gas mixer supplied from the air-gas mixing chamber; A nozzle chamber provided on a path from the gas valve side to the air-gas mixing chamber to supply the gas supplied through the gas valve to the air-gas mixing chamber; And An air supply valve unit provided between the path from the blower to the air-gas mixing chamber and the nozzle chamber to be opened or closed to supply or block air supplied from the blower to the air-gas mixing chamber; Premix burner, characterized in that provided. delete The method of claim 1, The air supply valve unit, An air supply valve having a valve body operable to supply or block air from the blower to the air-gas mixing chamber and a valve seat on which the valve body is seated; An elastic member for imparting an elastic force in a direction in which the air supply valve is closed; And a diaphragm configured to expand and close the air supply valve according to a pressure variation inside the nozzle chamber. The method of claim 3, wherein The air supply valve further comprises a support plate for supporting the valve body on one side of the diaphragm and a support for connecting the support plate to the valve body, wherein the elastic member is installed between the support plate and the valve seat Mixing burner. The method of claim 1, And the air supply valve part is opened and closed by a solenoid.

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