JP2007057163A - Cylindrical inner surface flame hole burner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical inner surface flame hole burner which reduces even generation of CO by preventing incomplete combustion without raising an exhaust amount of NOx. <P>SOLUTION: A secondary air supply hole 6 supplying secondary air from an interior of flame, and a swirl flow generating means 7 for generating a swirl flow of the secondary air, are provided in a substantially center part of a bottom face of a bottomed cylinder shaped burner body 1 having an opened top face and a cylindrical space part 2. Since the swirled secondary air will flow concentrated in a center of the cylindrical space part without spreading, and secondary air will not be supplied to flame hole vicinities provided on an inner wall of the burner body 1, generation of CO is suppressed by supplying the secondary air from the interior of flame without increasing a generated amount of NOx. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cylindrical inner flame hole burner.

  Conventionally, reduction of harmful substances generated during combustion has been an important issue, and in particular, in recent years, there has been an increasing demand for reduction of NOx. Therefore, various burners have been considered to reduce NOx. As one of them, a so-called cylindrical inner surface flame hole burner having a structure in which a number of flame holes are formed in the inner wall of a concave burner body is known. .

  FIG. 5 is a diagram showing a cylindrical inner flame hole burner, which has a bottomed cylindrical burner body 21 having an open top and a cylindrical space 22, a premixing chamber 23 for mixing combustion gas and air, A large number of the inner walls of the burner body 21 are provided with flame holes 24 through which premixed gas is ejected.

With the above-described configuration, the flame burns so as to rise from the flame hole 24, so that the secondary air indicated by the thick arrow is difficult to be supplied into the cylindrical space portion 22. Therefore, almost no secondary air is supplied to the vicinity of the flame hole 24 provided on the inner wall of the burner body 21, and NOx generated during combustion can be reduced.
JP-A-9-159119

  As described above, the cylindrical inner surface flame hole burner can suppress the amount of NOx generated by reducing the supply of secondary air to the vicinity of the flame hole, but it tends to cause incomplete combustion and CO is generated. There is. As a cause of this, the flame formed by the cylindrical inner surface flame hole burner tends to gather in the central part of the cylinder, and even if secondary air is supplied from the outside of the burner to the flame, it is difficult to reach the central part, It is conceivable that the center portion of the flame will be deficient in oxygen.

  Therefore, conventionally, a method has been adopted in which a hole is provided in the bottom surface of the burner body, secondary air is introduced from the hole, and the secondary air is supplied into the flame. However, since the secondary air introduced from the bottom surface is also supplied to the vicinity of the flame hole, an increase in the NOx emission value is unavoidable, and after accepting that the NOx value rises to some extent, the CO emission amount The secondary air volume was only adjusted to reduce the amount of air.

  The present invention is to solve the above-mentioned problems, and provides a cylindrical inner surface flame hole burner that can prevent incomplete combustion without increasing the NOx emission amount and reduce CO generation. Objective.

  The present invention provides a bottomed cylindrical burner body having an open top surface and a cylindrical space, a plurality of flame holes provided in the inner wall of the burner body, a premixing chamber for premixing fuel gas and air, A cylindrical inner surface flame hole burner having a secondary air supply hole for supplying secondary air provided in a substantially central portion of the bottom surface of the burner body, and a swirl flow generating means for generating a swirl flow in the secondary air It is.

  A bottomed cylindrical burner body having an open top surface and a cylindrical space; a plurality of flame holes provided in an inner wall of the burner body; a premixing chamber for premixing fuel gas and air; and a burner A secondary air supply hole that is provided at a substantially central portion of the bottom surface of the main body and supplies secondary air, and a secondary air that communicates with the secondary air supply hole and supplies secondary air downstream from the upper surface opening of the burner main body. A cylindrical inner surface flame hole burner characterized by having a passage.

  The cylindrical inner flame hole burner according to claim 2, wherein the secondary air passage is closed at a downstream end and has a plurality of secondary air ejection holes in a peripheral wall.

  4. The cylindrical inner flame hole burner according to claim 2, wherein the secondary air passage has a deflecting plate having a diameter larger than a diameter of a secondary air ejection portion. 5.

  By constructing as described above, secondary air can be supplied from the bottom of the burner to the inside of the flame without supplying secondary air to the vicinity of the flame hole, so incomplete without increasing NOx emissions. Combustion can be prevented and CO generation can be reduced.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode of the present invention, which is considered preferable, will be briefly described by showing the effects of the present invention.

  The present invention is a so-called cylindrical inner surface flame hole burner having a structure in which a large number of flame holes are formed in the inner wall of a bottomed cylindrical burner body having an open top surface and a cylindrical space portion, and is an approximate bottom surface of the burner body. A central part is provided with a secondary air supply hole for supplying secondary air from the inside of the flame, and a swirling flow generating means for generating a swirling flow in the secondary air.

  The flame formed by the cylindrical inner flame hole burner tends to collect in the central part of the cylinder, and even if secondary air is supplied to the flame from the outside of the burner, it is difficult to reach the central part. There may be oxygen deficiency in some areas. For this reason, a hole is provided in the substantially central portion of the bottom surface of the burner body, and secondary air is supplied from here to the inside of the flame to eliminate oxygen shortage and suppress the generation of CO.

  Further, the secondary air is concentrated in the center of the cylindrical space portion without being diffused in all directions due to the addition of the swirl flow when passing through the swirl flow generating means. Therefore, secondary air is not supplied to the vicinity of the flame hole provided on the inner wall of the burner body, so that the amount of NOx generated is not increased, and the secondary air to which the swirl flow is applied is burned. Since it mixes so that a flame may be involved when it contacts a flame, even if it is a small amount of secondary air, mixing with a flame is performed effectively and a favorable combustion state can be maintained.

  In addition, as other configurations, a secondary air supply hole for supplying secondary air from the inside of the flame to the substantially central portion of the bottom surface of the burner body, a secondary air communicating with the secondary air supply hole, and opening the secondary air to the upper surface of the burner body A secondary air passage leading downstream from the portion is provided.

  The secondary air introduced from the secondary air supply hole is guided to the downstream side of the upper surface opening of the burner body through the secondary air passage and then supplied to the combustion flame. Can be prevented, and the amount of NOx generated can be suppressed. In addition, since secondary air can be reliably supplied to the flame from the inside, oxygen shortage is eliminated, and generation of CO is suppressed.

  Specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a cylindrical inner surface flame hole burner according to the present invention. The burner body 1 has a bottomed cylindrical shape having an open top surface and a cylindrical space portion 2 therein. Is provided with a premixing chamber 3 for generating a premixed gas by mixing fuel gas typified by vaporized petroleum fuel such as kerosene, city gas and the like with primary air.

  The burner body 1 is provided with a number of flame holes 4 for injecting premixed gas over the entire circumference of the inner wall formed by the cylindrical space portion 2, and the flame holes 4 prevent backfire. A net member 5 is attached from the inside of the inner wall of the burner body 1.

  Near the center of the bottom surface of the burner body 1, a secondary air supply hole 6 for taking in secondary air and a swirl flow generating means 7 comprising a swirl plate provided with a plurality of blades are provided. A swirling flow is generated in the secondary air introduced into the cylindrical space 2 from the supply hole 6.

  In the above configuration, when an instruction to start combustion is issued, the fuel gas is injected into the premixing chamber 3. Then, since the surrounding air is also drawn into the premixing chamber 3 as primary air, a premixed gas in which the fuel gas and the primary air are premixed is generated in the premixing chamber 3. The premixed gas is ejected from a flame hole 4 provided on the inner wall of the burner body 1, and is ignited by an ignition device (not shown) to start combustion.

  When the combustion is started, secondary air is supplied to the flame, and the flame is completely burned by taking in the secondary air.

  A combustor configured using this cylindrical inner surface flame hole burner is provided with a blower (not shown), and air sent from the blower is supplied as secondary air to the flame from the outside of the burner body 1 (broken arrow). . In addition, since the flame is formed so as to rise upward from the flame hole 4, it has a structure in which secondary air is not easily supplied from the outside into the cylindrical space portion 2. Accordingly, since the secondary air from the blower is hardly supplied to the vicinity of the flame hole 4 provided on the inner wall of the burner body 1, the secondary air is supplied to the vicinity of the flame front, so that the amount of NOx generated is kept low. be able to.

  However, the flame formed by the burner tends to gather in the central part of the cylinder, and even if secondary air is supplied to the flame from the outside of the burner, it is difficult to reach the central part. Oxygen deficiency may occur. Therefore, secondary air is introduced from the secondary air supply hole 6 provided in the bottom surface of the burner body 1 into the cylindrical space portion 2 through the swirling flow generating means 7, and the secondary air is also supplied from the inside of the flame. (Solid arrow).

  The secondary air introduced from the secondary air supply hole 6 is concentrated in the center of the cylindrical space portion 2 without being diffused in all directions due to the addition of the swirling flow when passing through the swirling flow generating means 7. Since it flows, secondary air is not supplied to the vicinity of the flame hole 4 provided in the inner wall of the burner body 1. Therefore, the amount of NOx generated is not increased.

  In addition, since the secondary air to which the swirl flow is applied is mixed so as to involve the flame when it comes into contact with the combustion flame, the mixing with the flame is effective without supplying a larger amount of secondary air than necessary. It is possible to maintain a good combustion state and to shorten the flame, and to make the combustor compact.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  A secondary air supply hole 6 for taking in secondary air is provided substantially at the center of the bottom of the burner body 1. The secondary air communicates with the secondary air supply hole 6 and allows the secondary air to pass through the upper surface opening L of the burner body 1. A secondary air passage 8 that leads to the downstream side is provided in the cylindrical space 2. The secondary air passage 8 is open at the downstream end from which secondary air is ejected.

  In the above-described configuration, the secondary air supplied from the inside to the flame is introduced from the secondary air supply hole 6 on the bottom surface of the burner body 1, passed through the secondary air passage 8 and guided downstream. , Ejected downstream of the upper surface opening L of the burner body 1 and supplied to the flame. Accordingly, since the secondary air is not supplied near the flame hole 4, it is possible to prevent the generation amount of NOx from increasing.

  Next, a third embodiment of the present invention will be described with reference to FIG.

  A secondary air supply hole 6 for taking in secondary air is provided substantially at the center of the bottom of the burner body 1. The secondary air communicates with the secondary air supply hole 6 and allows the secondary air to pass through the upper surface opening L of the burner body 1. A secondary air passage 8 that leads to the downstream side is provided in the cylindrical space 2. The secondary air passage 8 is closed at the downstream end and has a plurality of secondary air ejection holes 9 for ejecting secondary air to the peripheral wall.

  In the above-described configuration, the secondary air supplied from the inside to the flame is introduced from the secondary air supply hole 6 on the bottom surface of the burner body 1, passed through the secondary air passage 8 and guided downstream. In the downstream of the upper surface opening L of the burner body 1, the secondary air ejection holes 9 are ejected in the circumferential direction of the burner body 1 and supplied to the flame. Therefore, since the generation amount of NOx is prevented and the secondary air is ejected in the circumferential direction of the burner body 1, the mixing with the flame is effectively performed and a good combustion state is maintained and shortened. Flames can be made, and the combustor can be made small.

  Next, a fourth embodiment of the present invention will be described with reference to FIG.

  A secondary air supply hole 6 for taking in secondary air is provided substantially at the center of the bottom of the burner body 1. The secondary air communicates with the secondary air supply hole 6 and allows the secondary air to pass through the upper surface opening L of the burner body 1. A secondary air passage 8 that leads to the downstream side is provided in the cylindrical space 2. The secondary air passage 8 has a plurality of secondary air ejection holes 9 through which secondary air is ejected. Further, the diameter of the secondary air passage 8 is larger than the diameter of the secondary air passage 8 downstream of the secondary air ejection hole 9. It is the structure provided with the direction change plate 10 which is.

  In the above-described configuration, the secondary air supplied from the inside to the flame is introduced from the secondary air supply hole 6 on the bottom surface of the burner body 1, passed through the secondary air passage 8 and guided downstream. The air is ejected from a secondary air ejection hole 9 provided in the secondary air passage 8 downstream of the upper surface opening L of the burner body 1. Then, the secondary air ejected from the secondary air ejection holes 9 is rectified by the deflecting plate 10 so that the direction is directed in the circumferential direction of the burner, and supplied to the flame. Therefore, an increase in the amount of NOx generated is prevented and the secondary air is rectified in the circumferential direction of the burner body 1, so that mixing with the flame is effectively performed and a good combustion state is maintained. Thus, the flame can be shortened and the combustor can be made compact.

It is sectional drawing of the cylindrical inner surface flame hole burner of Example 1 of this invention. It is sectional drawing of the cylindrical inner surface flame hole burner of Example 2 of this invention. It is sectional drawing of the cylindrical inner surface flame hole burner of Example 3 of this invention. It is sectional drawing of the cylindrical inner surface flame hole burner of Example 4 of this invention. It is sectional drawing of the conventional cylindrical inner surface flame hole burner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Burner main body 2 Cylindrical space part 3 Premixing chamber 4 Flame hole 6 Secondary air supply hole 7 Swirling flow generation means 8 Secondary air passage 9 Secondary air ejection hole 10 Turning plate

Claims (4)

  A bottomed cylindrical burner body having an open top surface and a cylindrical space, a plurality of flame holes provided in the inner wall of the burner body, a premixing chamber for premixing fuel gas and air, and a burner body A cylindrical inner surface flame hole burner comprising: a secondary air supply hole that is provided at a substantially central portion of the bottom surface for supplying secondary air; and a swirling flow generating means for generating a swirling flow in the secondary air.   A bottomed cylindrical burner body having an open top surface and a cylindrical space, a plurality of flame holes provided in the inner wall of the burner body, a premixing chamber for premixing fuel gas and air, and a burner body A secondary air supply hole provided in a substantially central portion of the bottom surface for supplying secondary air, and a secondary air passage communicating with the secondary air supply hole and supplying secondary air downstream from the upper surface opening of the burner body. A cylindrical inner flame hole burner characterized by comprising:   The cylindrical inner surface flame hole burner according to claim 2, wherein a downstream end of the secondary air passage is closed and a plurality of secondary air ejection holes are provided on a peripheral wall.   4. The cylindrical inner flame hole burner according to claim 2, wherein the secondary air passage has a deflecting plate having a diameter larger than a diameter of a secondary air ejection portion. 5.

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