JP2006132856A - Combustion apparatus with frame funnel with tip throttle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve combustion performance and to reduce combustion sound in a combustion apparatus having a miniaturized frame funnel. <P>SOLUTION: This combustion apparatus performs combustion by mixing combustion air supplied from a blower via a wind box, with liquid fuel injected in conical shape from a fuel injection nozzle 3. The frame funnel 1 of approximately cylindrical shape connected on the root side to the wind box and having a taper part 4 enlarged in inner diameter halfway is installed on the tip side of the combustion apparatus. The tip of the frame funnel 1 is provided with a ring-like throttle member for throttling the opening diameter of an outlet of the frame funnel 1, and the width of the throttle member 2 is determined to make the opening diameter of the outlet of the frame funnel 1 larger than a fuel injection region 8 injecting fuel in conical shape from the fuel injection nozzle 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a combustion apparatus having a frame funnel with a tip throttle.

  Combustion device that performs combustion by mixing combustion air supplied from a blower via a wind box and liquid fuel that is injected conically from a fuel injection nozzle. 2. Description of the Related Art Combustion apparatuses that are connected to a wind box and have a substantially cylindrical frame funnel having a tapered portion that expands the inner diameter in the middle are widely used. As disclosed in Japanese Patent Application Laid-Open No. 3-255802, it is known that a ring-shaped throttle member for narrowing the opening diameter of the frame funnel outlet is provided at the end of the frame funnel.

  When the front end of the frame funnel is squeezed by the throttle member, the air flowing along the wall surface in the frame funnel becomes a flow that is engulfed inward by the throttle member at the front end, and a swirling flow is generated. The fuel oil injected from the fuel injection nozzle is sufficiently mixed with the swirling flow of air by the frame funnel, so that the combustibility can be improved. The throttle member may be provided with an inclination in a direction in which the frame funnel is tapered. In some cases, the combustion performance can be further improved by providing the throttle member with an inclination.

  By the way, in the conventional combustion apparatus, the volume in the flame funnel is large, the fuel can be sufficiently vaporized in the flame funnel, and high combustion performance can be obtained. However, if the flame funnel has to be made smaller due to the demand for downsizing the combustion device, if the frame funnel is reduced in size, the combustion performance deteriorates and soot is deposited in the frame funnel.

Further, although combustion noise is generated during combustion by the combustion device, reduction of combustion noise is also an important theme, and a combustion device that can achieve both improvement in combustion performance and reduction in combustion noise has been desired.
JP-A-3-255802

  The problem to be solved by the present invention is to improve the combustion performance and further reduce the combustion noise in a combustion apparatus having a downsized frame funnel.

  The invention according to claim 1 is a combustion apparatus that performs combustion by mixing combustion air supplied from a blower via a wind box and liquid fuel that is injected conically from a fuel injection nozzle. In the combustion device in which the base side is connected to the wind box and a substantially cylindrical frame funnel with a taper part that expands the inner diameter is installed in the middle, the flame funnel outlet is connected to the tip of the frame funnel. A ring-shaped throttle member that throttles the opening diameter is provided, and the width of the throttle member is determined so that the opening diameter of the frame funnel outlet is wider than the fuel injection region that is injected conically from the fuel injection nozzle. It is characterized by being.

  The invention according to claim 2 is a combustion apparatus that performs combustion by mixing combustion air supplied from a blower via a wind box and liquid fuel injected in a conical shape from a fuel injection nozzle. In the combustion device in which the base side is connected to the wind box and a substantially cylindrical frame funnel with a taper part that expands the inner diameter is installed in the middle, the flame funnel outlet is connected to the tip of the frame funnel. A ring-shaped throttle member for reducing the opening diameter is provided, and the throttle member has an opening on the frame funnel outlet side first with respect to a plane perpendicular to the central axis of the fuel injection region that is injected conically from the fuel injection nozzle. An inclination of 5 to 20 degrees is provided in the direction of the diaphragm.

  According to a third aspect of the present invention, in the combustion apparatus having the frame funnel with the tip throttle, the throttle member is a surface perpendicular to the central axis of the fuel injection region that is injected conically from the fuel injection nozzle. On the other hand, the opening of the frame funnel outlet side is provided with an inclination of 5 to 20 degrees in the direction of the front throttle, and the opening diameter of the frame funnel outlet is injected conically from the fuel injection nozzle with the throttle member inclined. The width of the throttle member is determined so as to be wider than the fuel injection region.

  By implementing the present invention, combustion performance can be improved and combustion noise can be reduced.

  FIG. 1 is a cross-sectional perspective view of a frame funnel portion of a combustion apparatus embodying the present invention, FIG. 2 is a graph showing the relationship between the inclination angle of a throttle member provided at the tip of the frame funnel, the noise value, and the degree of smoke. FIG. 4 is a cross-sectional view when the combustion apparatus of the present invention is mounted on a boiler, and FIG. 4 is an explanatory diagram of the state of soot adhesion when a conventional frame funnel is simply downsized.

  First, the overall structure of the combustion apparatus will be described with reference to FIG. The boiler has a combustion chamber in the center and a combustion device that generates a downward flame at the top of the combustion chamber. A wind box 10 that rectifies combustion air sent from a blower 11 that sends combustion air to the combustion device is provided at the upper portion of the combustion device. A frame funnel 1 having a root side connected to the wind box 10 is installed on the front side of the wind box 10, and combustion air from the wind box 10 passes through the frame funnel 1.

  A fuel supply pipe 6 is provided at the center shaft portion of the combustion apparatus, and a fuel injection nozzle 3 is provided in the frame funnel 1 at the tip of the fuel supply pipe 6. The fuel injection nozzle 3 injects the liquid fuel sent through the fuel supply pipe 6 in a conical shape, and facilitates vaporization by atomizing the fuel. The fuel injected from the fuel injection nozzle 3 and the combustion air that has passed through the wind box 10 from the blower 11 are mixed in the frame funnel 1.

  The frame funnel 1 has a cylindrical portion having a tapered portion 4 that expands the inner diameter in the middle and a straight body portion 5 at the tip of the tapered portion 4. A disc-shaped diffuser 12 having a hole for fuel passage in the center is provided at the center of the frame funnel 1 and immediately below the fuel injection nozzle 3. A ring-shaped throttle member 2 that throttles the opening diameter of the frame funnel outlet is provided on the front side of the frame funnel straight body, and the throttle member 2 is a fuel injection region 8 that is injected conically from the fuel injection nozzle 3. The frame funnel outlet side opening is inclined with respect to a plane perpendicular to the central axis. The inclination angle of the throttle member 2 is selected from an angle of 5 to 20 degrees when a plane perpendicular to the central axis of the fuel injection region 8 is set to 0 degrees. Further, the throttle member 2 at the front end of the frame funnel has a width of the throttle member 2 so that the opening diameter of the frame funnel outlet is wider than the fuel injection region 8 injecting conically from the fuel injection nozzle 3. .

  When combustion is performed by the combustion device, combustion air is sent to the wind box 10 by the blower 11, rectified by the wind box 10, and sent to the frame funnel 1 that is a combustion cylinder. The combustion air flow 7 entering the frame funnel 1 flows along the inner wall surface of the frame funnel 1 because the diffuser 12 is provided at the center of the frame funnel 1. Since a throttle member 2 that narrows the opening diameter of the outlet is provided at the tip of the frame funnel 1, the air flow 7 that has flowed along the inner wall surface of the frame funnel 1 collides with the throttle member 2 and travels in the direction of travel. To shape the flow that wraps inside.

  The fuel injected from the fuel injection nozzle 3 is vaporized by receiving the heat of the flame while spreading conically in the frame funnel 1. Since the air flow 7 forms a flow that wraps inward at the front end portion of the frame funnel 1, the combustion air and the vaporized fuel are well mixed and burned.

  At this time, the opening diameter of the frame funnel outlet is made wider than the region extending in the injection direction of the fuel injected from the fuel injection nozzle 3, so that the fuel does not vaporize and reaches the position of the end of the frame funnel. Can be prevented from adhering to the diaphragm member 2. Even if the fuel injection angle of the fuel injection nozzle 3 is narrowed or the distance from the fuel injection nozzle 3 to the tip of the frame funnel is shortened, the frame funnel outlet opening diameter can be made wider than the region extended in the fuel injection direction. In that case, the combustion performance is greatly deteriorated. Therefore, by narrowing the width of the throttle member 2 and inclining the tip of the throttle member 2 in the forward direction of fuel injection, the frame funnel outlet opening diameter is made wider than the region extended in the fuel injection direction.

  As shown in FIG. 2, the inclination angle of the throttle member 2 changes the combustion state when the angle changes. When the inclination angle was 0 degree (a state perpendicular to the central axis of the fuel injection region 8 injecting conically from the fuel injection nozzle), the smoke generation degree was low, but the noise value generated by combustion was high. . When the inclination angle was 5 degrees, the amount of smoke generated was almost unchanged compared to the inclination angle of 0 degrees, but the noise value was significantly reduced. When the inclination angle is changed to 10 degrees, 15 degrees, and 20 degrees, the noise level gradually decreases, but the amount of smoke generated increases gradually. When the inclination angle is 25 degrees, the noise value does not change so much and remains low, but a measurement result is obtained that the smoke degree increases significantly.

  When the throttle member 2 is provided with an inclination, the air flow flowing along the wall surface in the frame funnel 1 forms a swirl flow that flows in the direction of the central axis of the frame funnel 1 while flowing in the forward direction of the combustion device. . Therefore, the turning force of air in the frame funnel 1 is reduced, and the combustion noise is thereby reduced. However, reducing the air turning force in the frame funnel 1 leads to a decrease in combustibility. Therefore, if the inclination angle is too large, the amount of smoke generated increases. The appropriate range where the amount of smoke generation is small and the amount of noise generation is small is when the inclination angle is 5 degrees to 20 degrees, so the inclination angle of the throttle member 2 is 5 to 20 degrees.

  In the case of the conventional combustion apparatus, since the boiler itself was large, it was possible to use a large frame funnel as described in the upper part of FIG. Therefore, even if the throttle member 2 is on the extension line of the fuel injected from the fuel injection nozzle 3, the fuel is vaporized in the middle because the distance from the fuel injection nozzle 3 to the throttle member 2 is long. Therefore, fuel that has not been vaporized never reaches the throttle member 2. However, in a small-sized boiler with high performance, the conventional large frame funnel 1 cannot be used, and the frame funnel 1 has to be downsized. When the frame funnel 1 is simply downsized, the distance from the fuel injection nozzle 3 to the throttle member 2 is shortened as shown in FIG. 4, and unvaporized fuel may adhere to the throttle member 2. . In this case, there has been a problem that soot adheres to the throttle member 2 (soot adhering portion 9) and the amount of smoke generated increases due to deterioration of combustibility.

  By making the structure of the throttle member 2 as described above, the fuel that has not been vaporized does not adhere to the frame funnel 1, so that soot adheres to the frame funnel 1 and accumulates, or a large amount of smoke is generated. That is no longer true. Furthermore, combustion noise can be reduced while maintaining good combustion.

Sectional perspective view of a frame funnel portion of a combustion apparatus implementing the present invention A graph showing the relationship between the inclination angle of the throttle member provided at the end of the frame funnel, the noise level, and the smoke level Sectional drawing when the combustion apparatus of the present invention is mounted on a boiler Soot adhesion explanatory diagram when the conventional frame funnel is simply downsized

Explanation of symbols

1 frame funnel
2 Diaphragm member
3 Fuel injection nozzle
4 Tapered part
5 Straight body
6 Fuel supply pipe
7 Air flow 8 Fuel injection area 9 Soot deposit
10 Wind box 11 Blower 12 Diffuser

Claims (3)

  Combustion device that performs combustion by mixing combustion air supplied from a blower via a wind box and liquid fuel that is injected conically from a fuel injection nozzle. A ring-shaped throttle member that squeezes the opening diameter of the frame funnel outlet at the tip of the frame funnel in a combustion device in which a substantially cylindrical frame funnel with a tapered portion that expands the inner diameter in the middle is connected to the wind box The throttle member width is determined such that the opening diameter of the frame funnel outlet is wider than the fuel injection region in which the fuel injection nozzle injects in a conical shape. Combustion device with a frame funnel.   Combustion device that performs combustion by mixing combustion air supplied from a blower via a wind box and liquid fuel that is injected conically from a fuel injection nozzle. A ring-shaped throttle member that squeezes the opening diameter of the frame funnel outlet at the tip of the frame funnel in a combustion device in which a substantially cylindrical frame funnel with a tapered portion that expands the inner diameter in the middle is connected to the wind box The throttle member is 5 to 20 degrees in a direction in which the opening on the frame funnel outlet side is the front throttle with respect to a plane perpendicular to the central axis of the fuel injection region that is injected conically from the fuel injection nozzle. A combustion apparatus having a frame funnel with a tip throttle, characterized in that the inclination is provided.   2. The combustion apparatus having a frame funnel with a tip throttle according to claim 1, wherein the throttle member has a frame funnel with respect to a plane perpendicular to a central axis of a fuel injection region that is injected conically from a fuel injection nozzle. A fuel injection region in which the opening at the outlet side is provided with an inclination of 5 to 20 degrees in the direction of the front throttle, and the opening diameter of the frame funnel outlet is injected conically from the fuel injection nozzle with the throttle member inclined. A combustion apparatus having a frame funnel with a tip throttle, wherein a width of the throttle member is determined so as to be wider.

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