JP2004226022A - Liquid fuel combustor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid fuel combustor capable of preventing condensation of a heat exchange body provided on an upper portion of a combustion chamber, and preventing overheat of a cooling air box. <P>SOLUTION: The liquid fuel combustor 10 comprises a combustion panel 16 to form a combustion chamber 11, a vaporizing cylinder 39 and a spray ring 40 disposed in the combustion chamber 11, and a fan 14 to feed air to an air chamber 13A provided on a lower portion of the combustion panel 16. A cooling air box 30 of a closed loop shape in plan view to introduce air fed from the fan 14 is provided between the combustion panel 16 and a heat exchange body 20. First and second air feed holes 33 and 34 are formed in the air box 30, and condensation on a wall surface of the heat exchange body 20 disposed on the upper portion of the liquid fuel combustor 10 and overheat of the cooling air box 30 can be simultaneously prevented by cooling air ejected from the air feed holes 33 and 34. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid fuel combustion apparatus, and more particularly, to a liquid fuel capable of preventing dew condensation of a heat exchanger through a cooling air box disposed above a burner and preventing overheating of the cooling air box. It relates to a combustion device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a liquid fuel combustion device used for a water heater or the like, a combustion plate that forms a combustion chamber in which fuel such as kerosene is burned inside, a vaporizing cylinder provided at substantially the center of the combustion plate, A scattering ring provided at a lower portion of the vaporizing cylinder to scatter the liquid fuel into the combustion chamber, a blower arranged below the vaporizing cylinder to supply air into the vaporizing cylinder, and a blower disposed above the combustion plate and the combustion plate. And a cooling air box arranged between the heat exchanger and the heat exchanger.
[0003]
In the liquid fuel combustion device, liquid fuel is scattered into a combustion chamber from a gap between the vaporizing cylinder and the scattering ring by rotation of the vaporizing cylinder, and spray combustion is performed by igniting the liquid fuel. By heating the vaporizing cylinder with the combustion heat, the liquid fuel in the vaporizing cylinder is vaporized, and the vaporized fuel is mixed with air supplied from the blower into the vaporizing cylinder to form the air-fuel mixture on the combustion plate. Vaporized combustion is performed by ejecting the fuel into the combustion plate from the flame hole. Further, the cooling air box blows out cooling air from an air supply hole formed on an upper surface of the cooling air box, and the blown air prevents dew condensation on a wall surface of the heat exchanger.
[0004]
[Problems to be solved by the invention]
However, in the liquid fuel combustion device, since only the air supply hole is provided on the upper surface of the cooling air box, the inner peripheral surface side of the cooling air box reduces the combustion heat in the combustion chamber. There is an inconvenience that it may be overheated by direct reception.
[0005]
[Object of the invention]
The present invention has been devised in view of such inconveniences, and its object is to achieve not only the prevention of dew condensation on the wall surface of the heat exchanger through the cooling air box, but also the cooling air box. An object of the present invention is to provide a liquid fuel combustion device capable of simultaneously preventing overheating.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, there is provided a liquid fuel combustion device disposed at a lower portion of a heat exchanger, comprising a combustion plate forming a combustion chamber at an upper portion, and a liquid provided at a lower portion of a vaporization cylinder disposed at the combustion chamber. A scatter ring that scatters fuel into a combustion chamber, a blow passage that supplies air to a lower surface side of the scatter ring, and a blower that supplies air to an air chamber provided at a lower portion of the combustion plate; The liquid fuel scattered into the combustion chamber is ignited from the gap between the spray ring and the spray ring to perform spray combustion, and the liquid fuel supplied into the vaporization cylinder by heating the vaporization cylinder with the combustion heat of the spray combustion. In a liquid fuel combustion device that performs vaporization combustion by ejecting the vaporized fuel from a flame hole formed in a side wall of the combustion plate,
Between the combustion plate and the heat exchanger, there is provided a cooling air box having a closed loop shape in plan view to which cooling air is supplied, and the upper surface of the cooling air box is provided with air along the wall surface of the heat exchanger. Is provided, while a second air supply hole is provided below the inner peripheral surface of the cooling air box for injecting air for preventing overheating of the inner peripheral surface. This prevents the dew condensation on the wall surface of the heat exchanger by air ejected from the first air supply hole, and also prevents overheating on the inner peripheral surface side of the cooling air box by air ejected from the second air supply hole. It is possible to do.
[0007]
In the present invention, a configuration is adopted in which a guide member is provided on the inner peripheral surface side of the cooling air box so as to make air ejected from the second air supply hole follow the inner peripheral surface of the cooling air box. Is preferred. With such a configuration, the cooling air ejected from the second air supply hole flows reliably along the inner peripheral surface, and the inner peripheral surface is efficiently cooled to prevent overheating of the cooling air box. it can.
[0008]
Further, a distal end of a communication pipe for introducing air from the blower is connected to an outer peripheral portion of the cooling air box, and a cooling air rectification guide is disposed inside the cooling air box corresponding to the distal end. , It is good to adopt the configuration. With this configuration, it is possible to prevent a relatively large amount of cooling air from flowing into the air supply hole near the distal end of the communication pipe, and to send the cooling air over the entire circumference of the cooling air box having a closed loop shape. Can be spanned.
[0009]
In this specification, "spray combustion" means combustion performed by igniting liquid fuel, and "vaporization combustion" means a mixture obtained by mixing vaporized liquid combustion with air. Means the combustion performed by igniting.
[0010]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0011]
FIG. 1 is a schematic plan view of a burner as a liquid fuel combustion apparatus according to the present embodiment, and FIG. 2 is a schematic plan view of the burner with parts removed from FIG. Have been. FIG. 3 is a schematic end view taken along line AA of FIG. In these figures, a burner 10 has an upper structure 12 including a combustion chamber 11 having a substantially square shape in a plan view, and a case having a bottomed container shape that supports the upper structure 12 from below and opens the upper part. 13 (see FIG. 3), and a blower 14 for supplying air to an air chamber 13 </ b> A in the case 13.
[0012]
As shown in FIG. 3, the upper structural body 12 is provided with a combustion chamber outer cylinder 15 having a bottom and a substantially rectangular cylindrical shape located on the outer side, and provided inside the combustion chamber outer cylinder 15 and on the bottom side of the case 13. A combustion chamber 16 having a bottomed substantially rectangular cylindrical shape forming an air chamber 13A, and an air-fuel mixture which is located substantially at the center inside the combustion chamber 16 and vaporizes a liquid fuel such as kerosene to form an air-fuel mixture. The combustion chamber 11 is provided with a forming means 18 and an air introducing portion 19 which is provided below the mixture forming means 18 and introduces air from the air chamber 13 </ b> A into the combustion chamber 11. In this embodiment, the upper part of the combustion platen 16, that is, the space formed between the air-fuel mixture forming means 18 is the combustion chamber 11, and the heat exchanger 20 (see FIG. 3) is located above the combustion chamber 11. Is arranged.
[0013]
The combustion chamber outer cylinder 15 includes a bottom wall 15A having a substantially square outer shape in plan view, and four side walls 15B rising upward from the outer periphery of the bottom wall 15A. In the bottom wall 15A, a first central through hole 21 is formed in a substantially central region, and a plurality of locations along the circumferential direction of the first central through hole 21 (in the present embodiment, except for the blower 14 side), First outer through holes 22 having a diameter smaller than that of the first central through hole 21 are formed at three places separated by an interval of approximately 90 degrees in the direction.
[0014]
The combustion plate 16 is disposed inside the combustion chamber outer cylinder 15 with a gap therebetween, and the gap forms a gas chamber 24 through which the air-fuel mixture formed by the air-fuel mixture forming means 18 passes. Further, the combustion plate 16 includes a bottom wall 16A having a substantially square outer shape in plan view, and four side walls 16B rising upward from the outer periphery of the bottom wall 16A. At the center of the bottom wall 16A, a second central through hole 26 and a second outer through hole 27 are formed above the first central through hole 21 and the first outer through hole 22, respectively. A large number of flame holes 29 are formed in the side wall 16B so that the air-fuel mixture from the gas chamber 24 can be jetted into the combustion chamber 11, and the upper side of the side wall 16B, that is, the upper part of the combustion plate 16 is cooled. An air box 30 is provided.
The cooling air box 30 has an inner / outer double wall structure having an inner peripheral surface 30A and an outer peripheral surface 30B made of a material having a good drawing property, for example, SUS430LX or the like, and an air chamber 31 is formed therebetween. As shown in FIG. 3, a distal end (upper end) of a communication pipe 32 that bypasses part of the air from the blower 14 as tertiary air is communicated with the outer peripheral surface 30 </ b> B. A plurality of first air holes 33 are formed in the upper surface of the cooling air box 30, that is, the upper inclined surface 30 </ b> C, along the circumferential direction, and the cooling air ejected from the first air holes 33 is formed. Flows along the inside of the wall surface of the heat exchanger 20. A plurality of second air supply holes 34 are formed in the lower part of the inner peripheral surface 30A along the circumferential direction, and cooling air ejected from these second air supply holes 34 into the space above the combustion chamber 11 is provided. The air flows upward along the inner peripheral surface of the cooling air box 30 via a guide member 35 supported between the upper end of the combustion panel 16 and the cooling air box 30. The guide member 35 is made of a material that can be obtained at a low cost, for example, a material such as SUH409L. As shown in FIGS. 5 to 7, the guide member 35 follows a substantially rectangular locus in plan view. It is composed of four sides of a support surface 35A and a guide surface 35B extending inward and obliquely upward to connect to each inner edge of the support surface 35A. Although the four guide surface portions 35B in this embodiment are provided discontinuously, they may be provided in a continuous shape so as to form a closed loop when viewed from above. Further, a cooling air rectification guide 38 is provided in the cooling air box 30, that is, in a position corresponding to the end of the communication pipe 32 in the air chamber 31. The rectifying guide 38 is configured by partially stepping the outer peripheral surface 30 </ b> B of the cooling air box 30 inward. By providing the rectifying guide 38, the first rectifying guide 38 corresponding to the end opening position of the communication pipe 32 is provided. Also, it is possible to prevent a relatively large amount of air from being blown out from the second air supply holes 33 and 34, and to allow the cooling air to reach the inside of the cooling air box 30 forming a closed loop along the surface of the rectifying guide 38. It has become.
[0016]
As shown in FIG. 3, the air-fuel mixture forming means 18 has a fine bell-shaped gap S1 between a bell-shaped vaporizing cylinder 39 whose lower part is open to the air chamber 13A side and a lower end of the vaporizing cylinder 39. The scattering ring 40 to be disposed and the first central through-hole 21 are supported by the formation edge region, and the upper end side is open to the vaporization cylinder 39 side, while the lower end side is open to the air chamber 13A side and the air chamber 13A is opened. A substantially cylindrical blower cylinder 41 for introducing the air as primary air for combustion into the vaporization cylinder 39, a fuel diffuser 42 located above the blower cylinder 41, and supplying liquid fuel to the combustion diffuser 42. And a fuel supply pipe 44.
[0017]
The fuel diffuser 42 has a substantially cylindrical side portion 42A whose upper and lower sides are open, an outward flange portion 42B connected to the upper end of the side portion 42A, and a inverted hook-shaped portion connected to the lower end side of the side portion 42A. And a top portion 42D fixed to the upper surface side of the flange portion 42B with a small gap S2 therebetween, which can receive the liquid fuel from the fuel supply pipe 44. The vaporizing cylinder 39 and the fuel diffuser 42 are supported by a common rotating shaft 46 located at the center thereof, and are provided so as to be integrally rotatable by driving a motor M1 having the rotating shaft 46 as an output shaft. At this time, the liquid fuel supplied to the receiving portion 42C of the fuel diffuser 42 is ejected from the gap S2 toward the upper portion of the inner wall 39B of the vaporizing cylinder 39 by the centrifugal force caused by the rotation.
[0018]
An air introduction portion 19 for sending air into the combustion chamber 11 includes a cylindrical air supply pipe 49 as an air supply passage connecting the first and second outer through holes 22 and 27, and the air supply pipe 49. And an air supply guide ring 50 that is provided between the upper end open side and the scattering ring 40 and is capable of forming an air supply gap P with the scattering ring 40. The air introduction unit 19 can supply the air that has passed through the air chamber 13 </ b> A as secondary air to the combustion chamber 11 from the air supply gap P via the air supply pipe 49.
[0019]
The air supply guide ring 50 has a base member 52 having a substantially crank-shaped cross section fixed to a bottom wall 16A of the combustion plate 16 by a screw 51 (see FIG. 2) or the like, and is provided on an upper end side of the base member 52. An upright member 53 having a substantially L-shaped cross section for forming an air supply gap P with the scattering ring 40.
[0020]
In the blower 14, the fan F rotates by driving the motor M2, so that air can be supplied to the air chamber 13A. As shown in FIG. 4, the blower 14 includes a hollow rectangular block 60 connected to the air chamber 13 </ b> A of the case 13. Partition walls 61, 62 are formed inside the block portion 60, and these partition walls 61, 62 form a primary air passage 63 in the center and secondary air passages on both sides sandwiching the primary air passage 63. An air passage 64 and a tertiary air passage 65 are formed. Here, as shown by the dotted line in FIG. 2, the air chamber 13A in the case 13 has a lower region of the vaporization cylinder 39 and a region on the side of the blower 14, and a lower region of the three air tubes 49 and an outer region of the air chamber 13A. A partition 68 is formed for partitioning the region into two regions. The partition wall 68 is provided at a height reaching the lower surface of the bottom wall 15A of the combustion chamber outer cylinder 15. The partition wall 68 allows the primary air chamber 70 for communicating the blower cylinder 41 with the primary air passage 63, and the vaporization cylinder 39. A secondary air chamber 71 that connects the surrounding air supply pipe 49 and the secondary air passage 64 is formed.
[0021]
As shown in FIG. 4, in the primary air passage 63 and the tertiary air passage 65, open / close plates 73 and 74 each having a substantially square planar shape are arranged. These opening / closing plates 73 and 74 are supported by a single rotating shaft 75 that penetrates the plate surface and forms a common shaft. The rotation shaft 75 extends in a direction crossing the primary to tertiary air passages 63 to 65, and one end thereof is connected to a motor M <b> 3 provided outside the block portion 60 so as to be rotatable. The opening / closing plates 73 and 74 are provided to be smaller than the opening areas of the corresponding primary air passage 63 and tertiary air passage 65, respectively. A certain gap is formed between the air passage 65 and the inner peripheral surface, so that a minimum air flow is achieved. Further, although not particularly limited, in the present embodiment, when the open / close plate 73 in the primary air passage 63 assumes a substantially vertical posture, the open / close plate 74 in the tertiary air passage 65 is oriented substantially horizontally. It is set as follows.
[0022]
Next, the combustion operation of the burner 10 will be described.
[0023]
First, when a switch (not shown) is turned on, the blower 14 and the motor M1 operate simultaneously. When the blower 14 operates, air is supplied from the blower 14 to the primary air chamber 70 and the secondary air chamber 71 via the primary air path 63 and the secondary air path 64, and the tertiary air path 65 and the communication pipe 32 The air is supplied into the air chamber 31 of the cooling air box 30 through the process. The air sent to the primary air chamber 70 is supplied into the vaporization cylinder 39 through the blower cylinder 41 and consumed as combustion air, while the air sent to the secondary air chamber 71 is supplied to the combustion chamber through an air supply pipe 49. The gas is supplied into the combustion chamber 11 and is partially used as combustion air while being used as cooling air for the vaporization cylinder 39. Further, the air supplied into the cooling air box 30 is ejected upward from the first air supply hole 33 and flows along the inner wall surface of the heat exchanger 20 disposed at the upper part. At the same time, the cooling air ejected into the upper part of the combustion chamber 11 from the second air supply hole 34 is guided in the upward flow by the inclined direction of the guide surface 35B of the guide member 35, and this air is cooled. By flowing along the inner peripheral surface of 30, the cooling air box 30 is prevented from being overheated. At this time, the air supplied from the communication pipe 32 into the cooling air box 30 becomes easy to flow along the circumferential direction of the cooling air box 30 by a kind of baffle action of the rectifying guide 38, and the communication pipe 32 There is no possibility that a large amount of cooling air locally flows through the air supply holes 33 and 34 near the front end. In addition, by adjusting the opening degree of the open / close plates 73 and 74 constituting the damper by driving the motor M3, the amount of air flowing through each of the air passages 63 to 65 is relatively adjusted.
[0024]
When the motor M1 operates, the vaporization cylinder 39 rotates together with the fuel diffuser 42, and liquid fuel such as kerosene is supplied from the fuel supply pipe 44 to the receiving portion 42C of the fuel diffuser 42. The liquid fuel is ejected from the minute gap S2 formed in the fuel diffuser 42 toward the inner wall 39B of the vaporizer cylinder 39 by the rotation of the fuel diffuser 42, and further, between the vaporizer cylinder 39 and the scattering ring 40. The gas is scattered into the combustion chamber 11 from the formed gap S1. The scattered liquid fuel is ignited by a spark of an ignition device (not shown) such as an igniter extending into the combustion chamber 11, and spray combustion starts.
[0025]
When the spray combustion is started, the vaporization cylinder 39 is heated by the combustion heat, and the liquid fuel ejected to the inner wall 39B of the vaporization cylinder 39 is vaporized. The vaporized fuel is mixed with the primary air supplied to the inside of the vaporization cylinder 39 to form a mixture, and the mixture passes through the gas chamber 24 and from each flame hole 29 of the combustion platen 16 into the combustion chamber 11. And vaporized combustion is performed.
[0026]
Therefore, according to such an embodiment, the cooling air box 30 is provided between the combustion plate 16 and the heat exchanger 20, and the cooling air box 30 is provided with the first and second air supply holes 33 and 34. Because of the provision, the effect that condensation on the wall surface of the heat exchanger 20 and overheating of the cooling air box 30 can be prevented at the same time is obtained.
[0027]
The best configuration and method for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this.
That is, the present invention has been particularly shown and described with particular reference to particular embodiments, but without departing from the spirit and purpose of the invention, Those skilled in the art can make various modifications in shape, material, quantity, and other detailed configurations.
Therefore, the description of the shapes, materials, and the like disclosed above are merely illustrative for the purpose of facilitating the understanding of the present invention, and do not limit the present invention. The description by the name of the member excluding some or all of the limitations such as is included in the present invention.
[0028]
For example, in the above-described embodiment, the rectifying guide 38 is provided at a position corresponding to the distal end of the communication pipe 32, but the opening diameter of the first and second air supply holes 33 and 34 at the position corresponding to the distal end and in the vicinity thereof is adjusted. If the diameter is relatively small, the rectifying guide 38 does not necessarily need to be provided.
[0029]
Further, in the above-described embodiment, the burner 10 including the combustion chamber 11 having a substantially square shape in a plan view is described. However, the present invention is not limited to this, and other polygonal, cylindrical, or elliptical combustion chambers may be used. The present invention is also applicable to a provided burner.
[0030]
【The invention's effect】
As described above, according to the present invention, it is possible to flow cooling air to the inner peripheral surface side of the cooling air box that prevents dew condensation on the wall surface of the heat exchanger disposed above the combustion plate. Thus, it is possible to provide a liquid fuel combustion device that has an unprecedented excellent effect that overheating of the cooling air box can be prevented.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of a burner according to an embodiment.
FIG. 2 is a schematic plan view of the burner in a state where a vaporizing cylinder and a scattering ring are removed from FIG.
FIG. 3 is a schematic end view taken along line AA of FIG. 1;
FIG. 4 is a schematic perspective view showing a lower shape of the blower.
FIG. 5 is a schematic perspective view of a guide member.
FIG. 6 is a plan view of a guide member.
FIG. 7 is a sectional view taken along line BB of FIG. 6;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Burner (liquid fuel combustion apparatus), 11 ... Combustion chamber, 16 ... Combustion board, 20 ... Heat exchanger, 29 ... Flame hole, 30 ... Cooling air box, 30A ... Inner peripheral surface, 30B ... Outer peripheral surface, 31 ... air chamber, 32 ... communication pipe, 33 ... first air supply hole, 34 ... second air supply hole, 35 ... guide member, 38 ... rectification guide, 39 ... vaporization cylinder, 40 ... scattering ring, 49 ... air supply pipe ( Air supply passage)

Claims (3)

A liquid fuel combustion device disposed at a lower portion of a heat exchanger, wherein a combustion plate forming a combustion chamber is provided at an upper portion, and a liquid fuel is provided at a lower portion of a vaporizing cylinder disposed in the combustion chamber to scatter liquid fuel into the combustion chamber. A scatter ring, an air supply passage for supplying air to a lower surface side of the scatter ring, and a blower for supplying air to an air chamber provided at a lower portion of the combustion plate, between the vaporization cylinder and the scatter ring. The liquid fuel scattered into the combustion chamber from the gap is ignited and spray combustion is performed, and the vaporization cylinder is heated by the combustion heat of the spray combustion to vaporize the liquid fuel supplied into the vaporization cylinder and vaporize the liquid fuel. In the liquid fuel combustion device which performs the vaporization combustion by ejecting the fuel from the flame holes formed on the side wall of the combustion plate,
Between the combustion plate and the heat exchanger, there is provided a cooling air box having a closed loop shape in plan view to which cooling air is supplied, and the upper surface of the cooling air box is provided with air along the wall surface of the heat exchanger. Is provided, while a second air supply hole for ejecting air for preventing overheating of the inner peripheral surface is provided below the inner peripheral surface of the cooling air box. Characteristic liquid fuel combustion device. A guide member is provided on an inner peripheral surface side of the cooling air box to guide air ejected from the second air supply hole along the inner peripheral surface of the cooling air box. 2. The liquid fuel combustion device according to 1. A distal end of a communication pipe that introduces air from the blower is connected to an outer peripheral portion of the cooling air box, and a cooling air rectification guide is disposed inside the cooling air box corresponding to the distal end. The liquid fuel combustion device according to claim 1 or 2, wherein:

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