Description

BURNER FOR FREE-MIXING HAVING MULTI-FUNCTION

Technical Field

[1] The present invention relates to a multifunctional free-mixing burner, and more particularly, to a multifunctional free-mixing burner which is an improvement of a manual medium-pressure Bunsen burner and can increase thermal efficiency even with a low gas injection pressure and reduce fuel costs. Background Art

[2] Nowadays, a manual medium-pressure Bunsen burner is commonly used everywhere. Now, the general configuration of the manual medium-pressure Bunsen burner will be described with reference to FIG. 1.

[3] FIG. 1 is a perspective view illustrating one example of a conventional manual medium-pressure Bunsen burner having a ring-shaped gas injecting member. As shown in FIG. 1, the conventional manual medium-pressure Bunsen burner 100 includes a burning unit 101 having a ring-shaped gas injecting member 101a, a gas inlet pipe 102 for supplying a predetermined amount of gas from a gas supply source, such as an LP gas vessel, into the gas injecting member 101a, and a manual ball valve 103 provided at the gas inlet pipe 102 for manually opening and closing the gas inlet pipe 102.

[4] The burning unit 101 is used to inject the predetermined amount of gas supplied from the gas supply source. As the injected gas is ignited while being mixed with atmospheric air, the burning unit 101 serves to generate flame. Here, the ring-shaped gas injecting member 101a of the burning unit 101 has gas discharge holes 101a (i.e. flame holes) such that the predetermined amount of gas supplied through the gas inlet pipe 102 is injected to the outside.

[5] FIG. 2 is a perspective view illustrating another example of a conventional manual medium-pressure Bunsen burner. Similar to the manual medium-pressure Bunsen burner 100 shown in FIG. 1, the conventional manual medium-pressure Bunsen burner 200 shown in FIG. 2 includes a burning unit 201 having a ring-shaped gas injecting member (not shown) formed with gas discharge holes (i.e. flame holes; not shown), a gas inlet pipe 202, and a manual ball valve 203. With the exception of the above configuration, the manual medium-pressure Bunsen burner shown in FIG. 2 further includes a protective cap 204 for preventing invasion of external impurities into the burning unit 201. Disclosure of Invention Technical Problem

[6] However, the above described examples of the conventional manual medium- pressure Bunsen burners 100 and 200 have the following many problems. Firstly, in conventional manual medium-pressure Bunsen burners, LP gas is mainly used as fuel gas in the burning units 101 and 201. The LP gas is selected to achieve high thermal power, but needs a high injection pressure of 2,500mmAQ.

[7] Secondly, due to the fact that the conventional burners employ a manual or artificial ignition manner, the burners may eject an excessive amount of gas when ignition is delayed only for one second, and consequently there is a risk of secondary explosive accidents.

[8] Thirdly, considering a burning process of the above described conventional manual medium-pressure Bunsen burners 100 and 200, if an artificial ignition is induced for igniting the gas, a predetermined amount of gas, injected from the gas discharge holes (i.e. flame holes) 101a perforated in the gas injecting member 101a, is mixed with the atmospheric air, thereby generating a flame. This results in diffusive burning of the gas that makes it difficult to achieve complete burning of the gas.

[9] To achieve complete burning using the conventional manual medium-pressure

Bunsen burners 100 and 200, it is necessary to sufficiently utilize the latent thermal energy of the fuel gas and to forcibly supply a greater amount of air. This becomes the factor as fuel costs increase.

[10] Fourthly, the conventional manual medium-pressure Bunsen burners 100 and 200 have the risk of a flame backward accident in that flame flows backward under the influence of the flow rate and pressure of the atmospheric air.

[11] Fifthly, although not shown, similar to gun type or separable burners, the conventional manual medium-pressure Bunsen burners 100 and 200 have a limited burning range equal to the total area of a blast tube and a diffuser and thus, cause a relatively great explosive noise during initial ignition.

[12] Sixthly, although the conventional manual medium-pressure Bunsen burners 100 and 200 achieve high thermal power with the use of a high injection pressure for burning, high thermal power has the risk that the gas discharge holes (i.e. flame holes) 101a perforated in the gas injection member 101a may be easily clogged by impurities or by the high temperature corrosion of the gas injecting member 101a. Therefore, it is necessary to exchange the gas injecting member 101a with a new one.

[13] In conclusion, the conventional manual medium-pressure Bunsen burners 100 and

200 have problems of increased manufacturing costs and deteriorated reliability of the products.

[14] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a multifunctional free-mixing burner which can achieve increased thermal efficiency with a low gas injection pressure and

eliminate the risk of a secondary explosive accident caused by the leakage of an increased amount of gas upon incomplete ignition.

[15] It is another object of the present invention to provide a multifunctional free-mixing burner which can complete burn fuel gas even when latent thermal energy of the fuel gas is insufficiently used, thereby reducing fuel costs.

[16] It is a further object of the present invention to provide a multifunctional free- mixing burner which includes a separate flame backward blocking plate, thereby preventing any flame backward accident even if the flame flows backward under the influence of the flow rate and pressure of atmospheric air.

[17] It is yet another object of the present invention to provide a multifunctional free- mixing burner which can prevent the clogging of gas discharge holes of a gas injecting member via the complete burning of fuel gas using a low gas injection pressure, thereby reducing the number of exchanging the gas injecting member with a new one and consequently, achieving reduced manufacturing costs and improved reliability of products. Technical Solution

[18] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a multifunctional free-mixing burner comprising a burning unit for burning gas injected into the burning unit under the assistance of air blown by an appropriate pressure, wherein the burning unit comprises: a gas injecting member located in a center portion of the burning unit and having a gas discharge hole for injection of the gas; an air injecting cap located in an edge portion of the burning unit and spaced apart from the gas injecting member by a predetermined distance and having a plurality of air discharge holes perforated in an inner wall surface thereof for injecting the air toward the gas injecting member; a gas discharge blocking plate located at an upper end of the gas injecting member and used to prevent the gas injected from the gas injecting member from being discharged vertically to the outside; and an ignition rod spaced apart from the gas injecting member by a predetermined distance and used to generate an ignition spark in the gas injected from the gas injecting member, and wherein the gas discharge hole is located at a position lower than a position of a part of the plurality of air discharge holes.

[19] The inner wall surface of the air injecting cap may be a curved or bent surface that is gradually narrowed toward the gas injecting member.

[20] The plurality of air discharge holes provided at the air injecting cap may have different flow rates from one another depending on their positions.

[21] The flow rates of the plurality of air discharge holes may increase far away from the gas discharge hole.

[22] The gas injecting member may be connected to a gas inlet pipe for receiving the gas supplied from a gas supply source.

[23] In accordance with another aspect of the present invention, there is provided a multifunctional free-mixing burner in which gas injected from a gas supply source is burn under the assistance of air blown by an appropriate pressure, comprising: a body defining the outer appearance of the burner; a drive unit connected to one end of the body and used to generate a drive force required for injection of the gas; a blower located below the drive unit and used to blow the air into the body by the appropriate pressure; an igniter located in the body and connected to the gas supply source for ignition of the gas; and a burning unit installed to the other end of the body, wherein the burning unit comprises: a gas injecting member located in a center portion of the burning unit and having a gas discharge hole for injection of the gas; an air injecting cap located in an edge portion of the burning unit and spaced apart from the gas injecting member by a predetermined distance and having a plurality of air discharge holes perforated in an inner wall surface thereof for injecting air toward the gas injecting member; a gas discharge blocking plate located at an upper end of the gas injecting member and used to prevent the gas injected from the gas injecting member from being discharged vertically to the outside; and an ignition rod spaced apart from the gas injecting member by a predetermined distance and used to generate an ignition spark in the gas injected from the gas injecting member, and wherein the gas discharge hole is located at a position lower than a position of a part of the plurality of air discharge holes.

[24] The inner wall surface of the air injecting cap may be a curved or bent surface that is gradually narrowed toward the gas injecting member.

[25] The plurality of air discharge holes provided at the air injecting cap may have different flow rates from one another depending on their positions.

[26] The flow rates of the plurality of air discharge holes may increase far away from the gas discharge hole.

[27] The gas injecting member may be connected to a gas inlet pipe for receiving the gas supplied from the gas supply source.

[28] The igniter may comprise a gas inlet pipe for supplying the gas into the gas injecting member.

[29] The igniter may comprise an electronic gas valve for opening or closing a gas inlet pipe connected to the gas injecting member, in order to selectively supply a predetermined amount of gas flowing through the gas inlet pipe into the gas injecting member.

[30] The electronic gas valve may be electrically connected to the drive unit for controlling the selective supply of the predetermined amount of gas.

[31] The ignition rod may be electrically connected to the drive unit for applying a voltage required for generation of the ignition spark in the gas.

Advantageous Effects

[32] According to a multifunctional free-mixing burner having the above described features, the following effects can be accomplished.

[33] Firstly, the burner of the present invention has the effects of achieving increased thermal efficiency with a low gas injection pressure and eliminating the risk of a secondary explosive accident caused by the leakage of an increased amount of gas upon incomplete ignition.

[34] Secondly, even when latent thermal energy of fuel gas is insufficiently used, the burner can complete burn the fuel gas. This has the effect of reducing fuel costs.

[35] Thirdly, by virtue of a separate flame backward blocking plate, the burner can prevent any flame backward accident even if the flame flows backward under the influence of the flow rate and pressure of atmospheric air.

[36] Fourthly, as a result of achieving the complete burning of fuel gas using a low gas injection pressure, the burner of the present invention can prevent the clogging of gas discharge holes perforated in a gas injecting member. This has the effect of preventing frequent exchange of the gas injecting member and consequently, resulting in reduced manufacturing costs and improved reliability of the products.

[37] Those skilled in the art including the present invention will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of technical ideas and essential characteristics of the invention. Accordingly, the following preferred embodiments of the present invention have been disclosed for illustrative purposes, and are not intended to limit the scope of the present invention. The scope of the present invention is disclosed in the following claims rather the detailed description of the preferred embodiments, and various modifications and substitutions derived by the mean and scope of the following claims and equivalents thereof have to be understood to be included in the scope of the present invention. Brief Description of the Drawings

[38] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[39] FIG. 1 is a perspective view illustrating an example of a conventional manual medium-pressure Bunsen burner having a ring-shaped gas injecting member;

[40] FIG. 2 is a perspective view illustrating another example of a conventional jet type manual medium-pressure Bunsen burner;

[41] FIG. 3 is a plan view illustrating a multifunctional free-mixing burner according to a first embodiment of the present invention;

[42] FIG. 4 is a front view of the multifunctional free-mixing burner shown in FIG. 3;

[43] FIG. 5 is an enlarged sectional view illustrating a burning unit included in the multifunctional free-mixing burner shown in FIG. 4;

[44] FIG. 6 is a view illustrating a burning process of the burning unit included in the multifunctional free-mixing burner shown in FIG. 5;

[45] FIG. 7 is an enlarged sectional view illustrating a burning unit included in a multifunctional free-mixing burner according to a second embodiment of the present invention;

[46] FIG. 8 is a view illustrating a burning process of the burning unit included in the multifunctional free-mixing burner shown in FIG. 7;

[47] FIG. 9 is an enlarged sectional view illustrating a burning unit included in a multifunctional free-mixing burner according to a third embodiment of the present invention;

[48] FIG. 10 is a view illustrating a burning process of the burning unit included in the multifunctional free-mixing burner shown in FIG. 9;

[49] FIG. 11 is an enlarged sectional view illustrating a burning unit included in a multifunctional free-mixing burner according to a fourth embodiment of the present invention;

[50] FIG. 12 is a view illustrating a burning process of the burning unit included in the multifunctional free-mixing burner shown in FIG. 11 ; and

[51] FIG. 13 is a plan view of an alternative embodiment of FIGS. 3, 7, 9 and 11, illustrating a multifunctional free-mixing burner having a plurality of burning units.

[52] *Description related to important elements of the drawings*

[53] 300, 400, 1300 : multifunctional free-mixing burner

[54] 301, 401, 1301 : body

[55] 302, 402, 1302 : drive unit

[56] 305, 405, 500, 700, 900, 1100, 1305 : burning unit

[57] 402a : transformer 402b : blower fan drive motor

[58] 402c : condenser 403 : blower

[59] 404 : igniter

[60] 405a, 505a, 705a, 805a, 905a, 1005a, 1105a, 1205a : ignition rod

[61] 405b, 505b, 605b, 705b, 905b, 1105b : gas injecting member

[62] 405c, 505c, 705c : gas inlet pipe 405d : electronic gas valve

[63] 410 : gas supply source 605a : air injecting member

[64] 505b , 605a , 705b , 805b , 905b , 1005b , 1205b : gas discharge hole

[65] 505d 1 , 505d2 , 505d 3 , 505d 4 , 505d 5 , 605b 1 : air discharge hole

[66] 505d, 705d, 905d, 1105d : air injecting cap

[67] 505e, 705e, 905e, 1105e : gas discharge blocking plate

[68] 505f, 605f, 705f, 905f, 1105f : flame backward blocking plate

[69] 705d , 705d , 705d , 705d , 705d : air discharge hole

[70] 805d , 805d , 805d , 805d , 805d : air discharge hole

[71] 1005d , 1005d , 1005d , 1005d , 1005d : air discharge hole

[72] 1205d , 1205d , 1205d , 1205d , 1205d : air discharge hole

[73] P , P : position

Best Mode for Carrying Out the Invention [74] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. [75] <First Embodiment

[76] FIG. 3 is a plan view illustrating a multifunctional free-mixing burner according to a first embodiment of the present invention, and FIG. 4 is a front view of the multifunctional free-mixing burner shown in FIG. 3. [77] The multifunctional free-mixing burner according to the present invention is configured such that gas discharge holes perforated in an outer wall surface of a gas injecting member provided in a burning unit have a lower position than the position of a part of air discharge holes perforated in an inner wall surface of an air injecting cap.

Now, the multifunctional free-mixing burner according to the present invention will be described with reference to FIG. 3. [78] As shown in FIG. 3, the multifunctional free-mixing burner 300 according to the present invention includes a body 301, a drive unit 302; 302a, 302b, and 302c, and a burning unit 305. [79] More specifically, as shown in FIG. 4, the multifunctional free-mixing burner 400 includes a body 401, a drive unit 402, a blower 403, an igniter 404, a burning unit 405, etc. [80] The body 401 defines the outer appearance of the multifunctional free-mixing burner. The drive unit 402 is connected to one end of the body 401, to provide a drive force required for injection of gas. [81] The drive unit 402 includes a transformer 402a that is an ignition device for applying a high voltage of approximately 12,000 volts to an ignition rod 405a, a blowing fan drive motor 402b for rotating the blower 403, i.e. a blowing fan that will be described hereinafter, so as to blow air, and a condenser 402c for charging and supplying a predetermined drive voltage. [82] The blower 403, takes the form of a blowing fan, is located below the drive unit 402 and adapted to blow an appropriate pressure of air into the body 401. The igniter 404 is

located in the body 401 and connected to a gas supply source 410 for igniting gas.

[83] Here, the igniter 404 is provided with a gas inlet pipe 405c for supplying gas into a gas injecting member 405b provided in the burning unit 405 that will be described hereinafter. The igniter 404 is further provided with an electronic gas valve 405d for opening or closing the gas inlet pipe 405c, to selectively supply a predetermined amount of gas flowing in the gas inlet pipe 405c into the burning unit 405.

[84] The electronic gas valve 405d is electrically connected to the drive unit 402, in order to open or close the gas inlet pipe 405c.

[85] The burning unit 405 is located on the other end of the body 401 and used to inject gas supplied from the gas supply source 410 for burning of the gas under the assistance of the appropriate pressure of blown air. The burning unit 405 included in the multifunctional free-mixing burner according to the present invention will now be described in detail with reference to Fig. 5 shown in an enlarged scale.

[86] FIG. 5 is an enlarged sectional view illustrating the burning unit included in the multifunctional free-mixing burner shown in FIG. 4. The burning unit included in the multifunctional free-mixing burner according to the present invention includes a gas injecting member, air injecting cap, gas discharge blocking plate, ignition rod, etc.

[87] Here, the burning unit included in the multifunctional free-mixing burner according to the present invention is configured such that gas discharge holes perforated in an outer wall surface of the gas injecting member provided at the burning unit have a lower position than the position of a part of air discharge holes perforated in an inner wall surface of an air injecting cap.

[88] The burning unit of the multifunctional free-mixing burner according to the present invention will be described in more detail with reference to FIG. 5.

[89] As shown in FIG. 5, a burner unit 500 of the multifunctional free-mixing burner according to the present invention includes a gas injecting member 505b, an air injecting cap 505d, a gas discharge blocking plate 505e, a flame backward blocking plate 505f, an ignition rod 505a, etc.

[90] First, the gas injecting member 505b is located in the center portion of the burning unit 500 and has gas discharge holes 505b for injection of gas.

[91] The air injecting cap 505d is located in an edge portion of the burning unit 500 such that the air injecting cap 505d is spaced apart from the gas injecting member 505b by a predetermined distance. The air injecting cap 550d has air discharge holes 505d perforated in an inner wall surface thereof, to inject air toward the gas injecting member 505b.

[92] The gas injecting member 505b is connected to a gas inlet pipe 505c that is used to supply gas from the gas supply source 410 (FIG. 4) into the gas injecting member 505b.

[93] The gas discharge holes 505b have a position P lower than a position P of a part of a plurality of air discharge holes 505d , 505d , 505d , 505d , 505d . The gas

1 2 3 4 5 injecting member 505b is connected to the gas inlet pipe 505c, for receiving gas from the gas supply source 410 (FIG. 4).

[94] With this configuration, under the induction of a spark by the ignition rod 505a that will be described hereinafter, a predetermined amount of gas injected from the gas discharge holes 505b is sequentially mixed with a predetermined amount of air injected from the air discharge holes 505d , 505d , 505d , 505d , 505d having different

1 2 3 4 5 heights from one another while rising in a height direction of the gas discharge holes 505b and a height direction of the air discharge holes 505d , 505d , 505d , 505d , 505d

1 1 2 3 4

. The sequential mixing increases the supply amount of air required for burning and thus, achieving improved thermal efficiency without requiring the sufficient use of latent thermal energy of fuel gas.

[95] More specifically, as a result of allowing the predetermined amount of gas staying in a predetermined region to be mixed sequentially with the predetermined amount of air injected from the plurality of air discharge holes 505d , 505d , 505d , 505d , 505d in a free mixing manner, it is possible to maintain high thermal power even with a low gas injection pressure of approximately 280mmAQ. Accordingly, even if the amount of gas supplied from the gas supply source is reduced, complete burning is possible, and therefore, costs of fuel gas can be efficiently reduced.

[96] The gas discharge blocking plate 505e is located at an upper end of the gas injecting member 505b and used to prevent gas injected from the gas injecting member 505b from being discharged vertically to the outside. The ignition rod 505a is spaced apart from the gas injecting member 505b by a predetermined distance, for generating an ignition spark in the gas injected from the gas injecting member 505b.

[97] The gas discharge blocking plate 505e is made of a stainless steel material having an outstanding heat convection property, so as to assist maintenance of high thermal power. Thereby, the gas discharge blocking plate 505e serves to maximize thermal efficiency.

[98] The ignition rod 505a is electrically connected to the drive unit 402 (FIG. 4), in order to apply a voltage required for generation of the gas ignition spark.

[99] The flame backward blocking plate 505f serves to prevent a flame backward accident even if flame flows backward under the influence of the flow rate and pressure of the atmospheric air.

[100] The burning process performed in the burning unit of the multifunctional free- mixing burner according to the present invention will be described with reference to FIG. 6.

[101] FIG. 6 is a view illustrating a burning process of the burning unit included in the

multifunctional free-mixing burner shown in FIG. 5. As stated above, the multifunctional free-mixing burner according to the present invention includes the body, drive unit, igniter, burning unit, etc as shown in FIG. 4.

[102] To begin a burning process in the burning unit of the multifunctional free-mixing burner according to the present invention, first, a certain switch provided at an outer surface of the body 401 (FIG. 4) or drive unit 402 (FIG. 4), for example, a push button switch (not shown) or a tumbler switch (not show), is turned on.

[103] In this case, an electronic gas valve adjustor (not shown), which serves as a controller (not shown) installed in the drive unit 402 (FIG. 4) electrically connected to the switch, is turned on, such that the electronic gas valve 405d (FIG. 4) installed at the burning unit 405 (FIG. 4) is opened. As a result, a predetermined amount of gas is supplied from the gas supply source 410 (FIG. 4) that is installed below the body 401 (FIG. 4) to the burning unit 405 (FIG. 4) through the gas inlet pipe 405c (FIG. 4).

[104] Simultaneously, the blowing fan drive motor 402b (FIG. 4), which is installed to the drive unit 402 (FIG. 4) electrically connected to the above described switch, is operated. Thereby, as the blower 403 (FIG. 4), i.e. the blowing fan begins to be rotated, air is blown into the burning unit 405 (FIG. 4) through the body 401 (FIG. 4).

[105] In this case, the transformer 402a as an ignition device installed to the drive unit

402 (FIG. 4) applies a high voltage of approximately 12,000 volts to the ignition rod 405a (FIG. 4) installed to the burning unit 405 (FIG. 4), and the condenser 402c (FIG. 4) installed to the drive unit 402 (FIG. 4) is continuously charged to maintain and supply a predetermined drive voltage to the transformer 402a.

[106] Here, for convenient explanation, the following description is limited to the configuration in which the drive unit 402 (FIG. 4) installed in the multifunctional free- mixing burner according to the present invention is connected to the end of the body 401 (FIG. 4) for implementation of the burning process, but the present invention is not limited thereto.

[107] After completing the burning process, a predetermined amount of gas and a predetermined amount of air are continuously introduced into the burning unit of the multifunctional free-mixing burner according to the present invention, and simultaneously, a voltage for generation of an ignition spark is continuously applied to the burning unit.

[108] The burning unit of the multifunctional free-mixing burner according to the present invention, as shown in FIG. 6, is configured such that a position P of gas discharge holes 605a is lower than a position P of a part of a plurality of air discharge holes 605b and the predetermined amount of gas and the predetermined amount of air injected from the gas discharge holes 605a and air discharge holes 605b stay in a predetermined region by the flame backward blocking plate 605f.

[109] Accordingly, under the induction of a spark by an ignition rod 605d, a predetermined amount of gas injected from the gas discharge holes 605a can be mixed sequentially with a predetermined amount of air injected from the air discharge holes 605b while rising in a height direction of the gas discharge holes 605a and a height direction of the air discharge holes 605b . As a result, it is possible to maintain high thermal efficiency even with a low gas injection pressure, thereby achieving efficient reduction of fuel costs.

[110] The multifunctional free-mixing burner according to the present invention, similar to a gun type or separable burner (not shown), can be ignited upon an initial ignition time even if the amount of gas injected from the gas discharge holes 605a is very little and therefore, can achieve considerable reduction in explosive noise generated during the burning process.

[I l l] Moreover, since the multifunctional free-mixing burner according to the present invention can increase the strength of thermal power even with a low gas injection pressure, it is possible to prevent damage to the gas injecting member 605b and the air injecting member 605a even under the conditions of a high pressure and high temperature. Accordingly, there is no need for exchange these members.

[112] The multifunctional free-mixing burner according to the present invention has the effects of lowering manufacturing costs and improving the reliability of products.

[113] Meanwhile, the multifunctional free-mixing burner according to the present invention has an improved structure of the air injecting cap provided in the burning unit so as to increase a heating area where a predetermined amount of gas and a predetermined amount of air are mixed and maintained, thereby reducing the height of flame and maintaining high thermal power. Mode for the Invention

[114] <Second Embodiment

[115] FIG. 7 is an enlarged sectional view illustrating a burning unit included in a multifunctional free-mixing burner according to a second embodiment of the present invention. FIG. 8 is a view illustrating a burning process of the burning unit included in the multifunctional free-mixing burner shown in FIG. 7.

[116] A burning unit of the multifunctional free-mixing burner according to the present embodiment has the same configuration as the burning unit of the multifunctional free- mixing burner of the previously described embodiment shown in FIG. 5. With the exception according to the present embodiment, the structure of the air injecting cap, provided in the burning unit of the multifunctional free-mixing burner, is improved as compared to the configuration shown in FIG. 5 such that a heating area where a predetermined amount of air and a predetermined amount of gas are mixed and

maintained is further increased. This improved structure is efficient to reduce the height of flame while maintaining high thermal power.

[117] The detailed configuration of the multifunctional free-mixing burner according to the present embodiment will now be described in more detail with reference to FIG. 7.

[118] As shown in FIG. 7, a burner unit 700 of the multifunctional free-mixing burner according to the present invention includes a gas injecting member 705b, an air injecting cap 705d, a gas discharge blocking plate 705e, a flame backward blocking plate 705f, an ignition rod 705a, etc.

[119] First, the gas injecting member 705b is located in the center portion of the burning unit 700 and has gas discharge holes 705b for injection of gas. The air injecting cap 705d is located at an edge portion of the burning unit 700 such that the air injection cap 705d is spaced apart from the gas injecting member 705b by a predetermined distance.

[120] The air injecting cap 705d has air discharge holes 705d perforated in an inner wall surface thereof, to inject air toward the gas injecting member 705b. The gas injecting member 705b is connected to a gas inlet pipe 705c for receiving gas supplied from the gas supply source 410 (FIG. 4).

[121] The gas discharge holes 705b have a position P lower than a position P of a part of a plurality of air discharge holes 705d , 705d , 705d , 705d , 705d . The gas injecting member 705b is connected to the gas inlet pipe 705c, for receiving gas supplied from the gas supply source 410 (FIG. 4). The inner wall surface of the air injecting cap 705d is a bent surface that it is gradually narrowed toward the gas injecting member 705b.

[122] As compared to the burning unit of the previously described multifunctional free- mixing burner as shown in FIG. 6, the burning unit 700 of the multifunctional free- mixing burner according to the present embodiment, as shown in FIG. 8, can achieve an increased heating area where a predetermined amount of gas injected from gas discharge holes 805b and a predetermined amount of air injected from air discharge holes 805d , 805d , 805d , 805d , 805d are mixed and maintained, under the induction

1 2 3 4 5 of a spark by an ignition rod 805a.

[123] Accordingly, the burning unit of the present invention can maintain higher thermal power with a low gas injection pressure than the burning unit shown in FIG. 6, and thus, can achieve more efficient reduction of fuel costs.

[124] The present invention is not limited to the above description. For example, by allowing the flow rate of air injected from the air discharge holes 805d , 805d , 805d , 805d , 805d to be increased far away from the gas discharge hole 805b , it is possible to achieve rapid mixing of a predetermined amount of air injected from the remote air discharge holes far away from the gas discharge holes, thus achieving an increase in thermal efficiency.

[125] Meanwhile, by improving the structure of the air injecting cap provided in the burning unit of the multifunctional free-mixing burner according to the present embodiment, it is possible to achieve an increased heating area where a predetermined amount of air and a predetermined amount of gas are mixed and maintained. Now, the burning unit of the present embodiment suitable for achieving the above effect will be described in more detail with reference to FIG. 9.

[ 126] <Third Embodiment

[127] FIG. 9 is an enlarged sectional view illustrating a burning unit included in a multifunctional free-mixing burner according to a third embodiment of the present invention. FIG. 10 is a view illustrating a burning process of the burning unit included in the multifunctional free-mixing burner shown in FIG. 9.

[128] A burning unit of the multifunctional free-mixing burner according to the present embodiment has the same configuration as the previously described burning unit of the multifunctional free-mixing burner shown in FIGS. 5 and 7.

[129] With the exception according to the present invention, the structure of the air injecting cap, provided in the burning unit of the multifunctional free-mixing burner, is improved as compared to those as shown in FIGS. 5 and 7, such that a heating area where a predetermined amount of air and a predetermined amount of gas are mixed and maintained is further increased, so as to reduce the height of flame while maintaining high thermal power.

[130] The detailed configuration of the multifunctional free-mixing burner according to the present embodiment will now be described in more detail with reference to FIG. 9.

[131] As shown in FIG. 9, a burning unit 900 of the multifunctional free-mixing burner according to the present embodiment includes a gas injecting member 905b, an air injecting cap 905d, a gas discharge blocking plate 905e, a flame backward blocking plate 905f, an ignition rod 905a, etc.

[132] Here, organic and functional relationships between constituent elements provided in the burning unit 900 of the multifunctional free-mixing burner according to the present embodiment are identical to organic and functional relationships between the constituent elements provided in the burning units 500 and 700 shown in FIGS. 5 and 7, and therefore, detailed description thereof will be omitted hereinafter. With the exception of the present invention, it is noted that an inner wall surface of the air injecting cap 905d is a curved surface that is gradually reduced toward the gas injecting member 905b.

[133] As compared to the burning units of the previously described multifunctional free- mixing burner as shown in FIGS. 6 and 8, the burning unit 900 of the multifunctional free-mixing burner according to the present embodiment, as shown in FIG. 10, can achieve an increased heating area where a predetermined amount of gas injected from

gas discharge holes 1005b and a predetermined amount of air injected from air discharge holes 1005d , 1005d , 1005d , 1005d , 1005d are mixed and maintained,

1 2 3 4 5 under the induction of a spark by an ignition rod 1005a.

[134] Accordingly, the burning unit of the present embodiment can maintain higher thermal power even with a low gas injection pressure than the burning units shown in FIGS. 6 and 8, and thus, can more efficiently reduce costs of fuel gas.

[135] Of course, the present invention is not limited to the above description. For example, by allowing the flow rate of air injected from the air discharge holes 1005d , 1005d , 1005d , 1005d , 1005d to be increased far away from the gas discharge holes 805b , it is possible to achieve rapid mixing of a predetermined amount of air injected from the remote air discharge holes located far away from the gas discharge holes, thus achieving increased thermal efficiency.

[136] Meanwhile, by improving the structure of the air injecting cap provided in the burning unit of the multifunctional free-mixing burner according to the present embodiment, it is possible to achieve an increased heating area where a predetermined amount of air and a predetermined amount of gas are mixed and maintained. Now, the burning unit of the present embodiment suitable for achieving the above effect will be described in more detail with reference to FIG. 11.

[137] <Fourth Embodiment

[138] FIG. 11 is an enlarged sectional view illustrating a burning unit included in a multifunctional free-mixing burner according to a fourth embodiment of the present invention. FIG. 12 is a view illustrating a burning process of the burning unit included in the multifunctional free-mixing burner shown in FIG. 11.

[139] A burning unit of the multifunctional free-mixing burner according to the present embodiment has the same configuration as the previously described burning units of the multifunctional free-mixing burner shown in FIGS. 5, 7 and 9.

[140] With the exception according to the present embodiment, the structure of the air injecting cap, provided in the burning unit of the multifunctional free-mixing burner, is improved as compared to those as shown in FIGS. 5, 7 and 9, such that a heating area where a predetermined amount of air and a predetermined amount of gas are mixed and maintained is further increased, so as to reduce the height of flame while maintaining high thermal power. The detailed configuration of the multifunctional free-mixing burner according to the present embodiment will now be described in more detail with reference to FIG. 11.

[141] As shown in FIG. 11, a burning unit 1100 of the multifunctional free-mixing burner according to the present embodiment includes a gas injecting member 1105b, an air injecting cap 1105d, a gas discharge blocking plate 1105e, a flame backward blocking plate 1105f, an ignition rod 1105a, etc.

[142] Here, organic and functional relationships between constituent elements provided in the burning unit 1100 of the multifunctional free-mixing burner according to the present embodiment are identical to organic and functional relationships between constituent elements provided in the burning units 500, 700, and 900 shown in FIGS. 5, 7 and 9, and therefore, detailed description thereof will be omitted hereinafter.

[143] With the exception of the present invention, it is noted that an inner wall surface of the air injecting cap 1105d is a curved surface that is gradually reduced toward the gas injecting member 1105b.

[144] As compared to the previously described burning units of the multifunctional free- mixing burner as shown in FIGS. 6, 8 and 10, the burning unit 1100 of the multifunctional free-mixing burner according to the present embodiment, as shown in FIG. 12, can achieve an increased heating area where a predetermined amount of gas injected from gas discharge holes 1205b i and a predetermined amount of air injected from air discharge holes 1205d , 1205d , 1205d , 1205d , 1205d are mixed and maintained, under the induction of a spark by an ignition rod 1205a.

[145] Accordingly, the burning unit of the present invention can maintain higher thermal power even with a low gas injection pressure than the burning units shown in FIGS. 6, 8 and 10, and thus, can more efficiently reduce costs of fuel gas.

[146] Similarly, the present invention is not limited to the above description. For example, by allowing the flow rate of air injected from the air discharge holes 1205d i , 1205d ,

1205d , 1205d , 1205d to be increased far away from the gas discharge holes 1205b , it is possible to achieve rapid mixing of a predetermined amount of air injected from the remote air discharge holes located far away from the gas discharge holes, thus achieving an increase in thermal efficiency.

[147] Meanwhile, when providing the multifunctional free-mixing burner according to the present embodiment with a plurality of burning units, it is possible to increase a burning capacity of the burner. Now, the multifunctional free-mixing burner according to an embodiment of the present invention will be described in more detail with reference to FIG. 13.

[148] FIG. 13 is a plan view illustrating the multifunctional free-mixing burner having a plurality of burning units according to an alternative embodiment of FIGS. 3, 7, 9 and 11.

[149] As shown in FIG. 13, the multifunctional free-mixing burner 1300 according to the present embodiment includes a body 1301 and a drive unit 1302; 1032a, 1302b, and 1302c, similar to the configuration as shown in FIG. 3, but includes a plurality of burning units 1305.

[150] The above mentioned constituent elements provided in the multifunctional free- mixing burner 1300 of the present embodiment have the same organic relationship as

the organic relationship of constituent elements provided in the multifunctional free- mixing burner 300 shown in FIG. 3, and therefore, detailed description thereof will be omitted.

[151] With the exception of the present invention, since the multifunctional free-mixing burner 1300 according to the present embodiment includes one or more burning units 1305, the multifunctional free-mixing burner 1300 can achieve an increased burning capacity as compared to the multifunctional free-mixing burner 300 shown in FIG. 3, and improve reliability of products.

[152] Meanwhile, for convenient explanation, although several different configurations of the air injecting caps 505d, 705d, 905d, and 1105d provided in the burning units 500, 700, 900, and 1100 of the multifunctional free-mixing burner according to the present invention are described as stated above, the present invention is not limited thereto. For example, the air injecting caps 505d, 705d, 905d, and 1105d provided in the burning units 500, 700, 900, and 1100 may have a certain pattern defined by a curved or bent surface in which air discharge holes are perforated. This configuration allows even a small amount of gas to be mixed and burn in a multifunctional fee-mixing manner, thereby resulting in more efficient reduction in costs of fuel gas. Industrial Applicability

[153] As apparent from the above description, the multifunctional free-mixing burner according to the present invention can achieve increased thermal efficiency even with a low gas injection pressure and reduced fuel costs when the burner is used as a conventional domestic burner. If necessary, the multifunctional free-mixing burner of the present invention is available in all industrial products, for example, an industrial burner for use in traffic lane plating vehicles, and cooking burners requiring high thermal power.

[154] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.