JP2007024382A - Liquid fuel combustor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid fuel combustor effectively suppressing generation of NOx, and capable of also suppressing generation of CO. <P>SOLUTION: A substantially L shaped secondary air inflow preventing plate 12 is provided for preventing inflow of secondary air to a burner port part 9 of a burner 3, and a space part 13 passing one part of air from a blower 2 is formed between the secondary air inflow preventing plate 12 and a front face of a combustion chamber 5. Accordingly, generation of NOx is suppressed by preventing a large amount of secondary air that has flowed into the combustion chamber 5 from flowing into the burner port part 9 of the burner 3, and since an appropriate amount of air having passed through a space part 13 is supplied to the burner port part 9 of the burner 3, generation of CO due to shortage of primary air can be suppressed also. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid fuel combustion apparatus such as a fan heater.

  A conventional combustion apparatus of this type is shown in FIG. In FIG. 7, a main body case 21 has a blower 22 that takes in indoor air, a burner 23 that burns liquid fuel to generate combustion exhaust gas, a flame hole portion 24 in which a flame is formed, a flame of the burner 23, and a combustion gas upward. Are provided with a combustion chamber 25 for discharging the air and an air outlet 26 for blowing warm air out of the main body case 21.

  The combustion chamber 25 has a plurality of secondary air intake holes 27 for taking in air from the blower 22 into the combustion chamber 25 and supplying it as secondary air to the flame on the back, and inside the combustion chamber 24. The shielding means 28 is provided so that it may be divided | segmented up and down.

  In the above-described configuration, the liquid fuel is heated by a vaporizer (not shown) to become a vaporized gas, and this vaporized gas is mixed with primary air to become a mixed gas, which is ejected from the flame hole 24 and starts to burn in the burner 23. .

  When combustion in the burner 23 is started, room air is taken into the main body case 21 by the rotation of the blower 22, and the taken-in air is a secondary air intake hole provided in the back surface of the combustion chamber 25. 27 flows into the combustion chamber 25 and is supplied as secondary air to the flame generated in the burner 23. By taking in the secondary air, the flame is completely burned.

  By the way, the secondary air is supplied in an amount necessary for complete combustion of the flame depending on the rotation of the blower 22 and the number and size of the secondary air intake holes 27, but the flame is completely burned in the combustion chamber 25. Actually, secondary air is supplied in excess of the necessary amount in order to reduce the flame. Therefore, if a part of the secondary air supplied in a large amount flows into the flame hole portion 24 of the burner 23, a problem arises that a large amount of NOx is generated by promoting the oxidation reaction of the flame.

Therefore, a shielding means 28 is provided inside the combustion chamber 25, and the secondary air is introduced into the lower part of the combustion chamber 25 divided by the shielding means 28, that is, into the flame hole 24 of the burner 23. This prevents the generation of NOx while supplying secondary air necessary for complete combustion (Patent Document 1).
JP-A-11-14039

  That is, in such a combustion apparatus, the amount of primary air mixed with the vaporized gas is reduced, and further, the generation of NOx is suppressed by reducing the oxygen in the vicinity of the flame hole of the burner, and then the secondary air is supplied. Thus, the flame is completely burned to suppress the generation of CO.

  However, when the primary air mixed with the vaporized gas is reduced for some reason, since the inflow of secondary air to the lower part of the combustion chamber is blocked by the shielding means, almost no oxygen is supplied to the flame hole, The lower part of the combustion chamber is in a state where CO is very easily generated. And if a flame contacts a shielding means in such a state, a flame will be cooled and temperature will fall. However, if the temperature of the flame becomes too low, it becomes difficult to completely burn even if secondary air is supplied, so there is a problem that a large amount of CO may be generated and discharged as soot from the outlet. there were.

  An object of the present invention is to provide a liquid fuel combustion apparatus capable of suppressing the generation of NOx and effectively suppressing the generation of CO while solving the above problems.

  The present invention includes a main body case, a burner that burns liquid fuel to generate combustion exhaust gas, a combustion chamber that is provided so as to surround the burner, a blower that takes air into the main body case, and a blower from the blower A secondary air intake hole for taking air into the combustion chamber as secondary air; and a substantially L-shaped secondary air inflow prevention plate for preventing the secondary air from flowing into the burner, wherein the secondary air inflow The liquid fuel combustion apparatus is characterized in that a space for allowing a part of the air from the blower to pass therethrough is formed between the prevention plate and the front surface of the combustion chamber.

  The secondary air inflow prevention plate is provided so that a substantially L-shaped horizontal portion is at a position equal to or lower than a lower end of the secondary air intake hole. It is a liquid fuel combustion apparatus of description.

  3. The liquid fuel combustion apparatus according to claim 2, wherein the horizontal portion of the secondary air inflow prevention plate has a length that does not contact the flame.

  4. The liquid fuel combustion apparatus according to claim 3, wherein a bead is formed on a front surface of the combustion chamber, and the space is formed by the bead and the secondary air inflow prevention plate. It is.

  The liquid fuel combustion apparatus according to claim 4, wherein the secondary air inflow prevention plate is attached to a front surface of the combustion chamber so as to absorb thermal expansion.

  By configuring as described above, it is possible to control the secondary air flowing into the flame hole portion of the burner. Therefore, it is possible to suppress the generation of CO as compared with the conventional case while suppressing the generation of NOx.

  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.

  A liquid fuel combustion apparatus according to the present invention is a combustion apparatus that takes in air from a blower into a combustion chamber through a secondary air intake hole, and supplies this air as secondary air to a flame formed by a burner. A secondary air inflow prevention plate for preventing the secondary air from flowing into the flame hole of the burner is provided.

  The secondary air inflow prevention plate is substantially L-shaped so as to be attached along the inclination of the front surface of the combustion chamber, and between the front surface of the combustion chamber in a state where the secondary air inflow prevention plate is attached. A shape is formed so that a space portion is formed, and a part of the air from the blower is allowed to pass through the space portion.

  In other words, a substantially L-shaped secondary air inflow prevention plate protrudes from the front of the combustion chamber inside the combustion chamber, and the secondary air flowing into the combustion chamber from the secondary air supply hole or the upper portion of the combustion chamber Since the air inflow prevention plate prevents the air from flowing into the flame hole of the burner, the generation of NOx is suppressed.

  In addition, since an appropriate amount of the air that has passed through the space is supplied to the flame hole of the burner, the generation of CO due to incomplete combustion can be suppressed even when the primary air is insufficient for some reason.

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

  FIG. 1 is a side view of a liquid fuel combustion apparatus. A main body case 1 generates a combustion exhaust gas by burning a blower 2 that takes outside air into the main body case 1 and pumps it, and liquid fuel such as kerosene. A burner 3 to be fixed, a burner box 4 for fixing the burner 3, and a combustion chamber 5 provided on the burner box 4, and a combustion exhaust gas generated by combustion of the burner 3 and a blower 2 in the main body 1. It mixes with the taken-in air, and is comprised so that it may discharge | emit as warm air from the blower outlet 6 provided in the front lower position of the main body 1. FIG.

  The burner 3 mixes a vaporized gas obtained by vaporizing liquid fuel with a vaporizer (not shown) and primary air to form a mixed gas, a igniter 8 that ignites the mixed gas, and burns the mixed gas. It is comprised from the flame hole part 9. FIG.

  The combustion chamber 5 has an opening 10 through which combustion exhaust gas is discharged in the upper part, and a part of the air from the blower 2 is taken in on the rear side for supplying secondary flame to the flame formed by the burner 3. A plurality of secondary air intake holes 11 are provided. A secondary air inflow prevention plate 12 is attached to the front surface.

  The secondary air inflow prevention plate 12 is substantially L-shaped by the horizontal portion 12a and the inclined portion 12b, and the horizontal portion 12a is at a position equal to or lower than the lower end of the secondary air intake hole 11. The horizontal portion 12 a is provided so as to prevent the secondary air flowing into the combustion chamber 5 from the secondary air intake hole 11 from flowing into the flame hole portion 9 of the burner 3. .

  However, if the flame touches the horizontal portion 12a during combustion, the temperature of the flame decreases and CO is generated. Therefore, the horizontal portion 12a has a length that does not touch the flame.

As shown in FIG. 2, a space portion 13 is formed between the inclined portion 12 b of the secondary air inflow prevention plate 12 and the front surface of the combustion chamber 5, and the space portion 13 flows into the combustion chamber 5. An air curtain is formed by passing a part of the air. In addition, the shape of the secondary air inflow prevention plate 12 should just be such that the space part 13 is formed between the front surfaces of the combustion chamber 5 in this way, and is not limited to the shape of the embodiment.

  Further, the combustion chamber 5 and the secondary air inflow prevention plate 12 receive a heat from the flame during combustion and become considerably high temperature, and thermal expansion occurs in each of them. It is attached to the front surface of the combustion chamber 5 so that it can be absorbed. For example, in this embodiment, a notch is provided in the front surface of the combustion chamber 5 so that the longitudinal ends of the inclined portion 12b of the secondary air inflow prevention plate 12 are hooked and fixed to the front surface of the combustion chamber 5 and the secondary air inflow is fixed. One end or a plurality of spots are welded at one end so that the prevention plate 12 does not come off. The method of attaching the secondary air inflow prevention plate 12 is not limited to the present embodiment as long as it can absorb thermal expansion.

  A combustion chamber heat shield 14 is provided around the combustion chamber 5 so as to cover the combustion chamber 5. Between the combustion chamber 5 and the combustion chamber heat shield 14, the combustion exhaust gas and the air from the blower 2 are separated. It is comprised as the warm air channel | path 15 which mixes and makes warm air.

  Next, the operation in the above configuration will be described.

  When the operation of the combustion apparatus is started, the liquid fuel is heated and vaporized by a vaporizer (not shown) to become vaporized gas, and the vaporized gas is ejected to the mixing tube 7. When the vaporized gas is ejected, the surrounding air is drawn into the mixing tube 7 as primary air by the ejection force, and the air introduced into the main body 1 by the rotation of the blower 2 is also mixed from below the burner box 4. Since the primary air is pushed into the pipe 7, the primary air is mixed with the vaporized gas described above to become a mixed gas. The mixed gas is ejected from the flame hole 9, ignited by the ignition device 8, and starts to burn in the burner 3.

  The air from the blower 2 also flows into the combustion chamber 5 from the secondary air intake hole 11 provided on the back surface of the combustion chamber 5, and is supplied to the flame as secondary air. And since the opening 10 is provided in the upper part of the combustion chamber 5, the air from the air blower 2 flows in into the combustion chamber 5 also from the opening 10, and is similarly supplied to a flame as secondary air.

  In FIG. 3, the arrows indicate the flow of the secondary air described above, and the secondary air flows downward from the horizontal portion 12 a of the secondary air inflow prevention plate 12 provided on the front surface of the combustion chamber 5. Therefore, the secondary air does not flow into the flame hole 9 of the burner 3 and a sufficient amount is supplied to the flame. Therefore, NOx can be reduced while maintaining a good combustion state.

  Further, a portion of the secondary air is introduced into a space portion 13 formed between the front surface of the combustion chamber 5 and the inclined portion 12b of the secondary air inflow prevention plate 12, and the space portion The secondary air passing through 13 serves as an air curtain. Then, since an air curtain receives the heat from a flame and prevents that the temperature of the combustion chamber 13 front surface rises, durability of the combustion chamber 5 can be improved.

  Thereafter, the secondary air introduced into the space 13 is supplied to the flame hole 9 of the burner 3. Therefore, even if the primary air is reduced due to some cause and oxygen is insufficient, a slight amount of air is supplied to the flame hole 9 so that the flame temperature becomes too low. This prevents the generation of CO.

  Since most of the secondary air flowing into the combustion chamber 5 is prevented from flowing into the flame hole 9 of the burner 3 by the secondary air inflow prevention plate 12, a large amount of NOx is not generated. However, if secondary air is introduced into the space 13 more than necessary, the amount of NOx generated increases, so the volume of the space 13 must be determined so as to suppress both CO and NOx generation. Don't be.

  The combustion exhaust gas generated by the combustion ascends the combustion chamber 5 and is discharged to the warm air passage 15 from the opening 10 provided in the upper part. Since the air flow from the blower 2 also flows into the hot air passage 15, the combustion exhaust gas is mixed with the air from the blower 2 in the hot air passage 15 to become warm air from the outlet 6 to the outside of the main body 1. Discharged.

  4 and 5 show the combustion chamber 5 according to the second embodiment of the present invention. A bead 16 is formed on the front surface of the combustion chamber 5, and the bead 16 increases the strength of the combustion chamber 5. It absorbs expansion due to heat from the combustion exhaust gas and plays a role of preventing the combustion chamber 5 from being deformed.

  The secondary air inflow prevention plate 12 is attached to the front surface of the combustion chamber 5 so as to cover a part of the bead 16, and the space portion 13 has a recess made by the bead 16 and a secondary air inflow prevention plate. 12 inclined portions 12b.

  That is, the bead 16 makes a recess in the front surface of the combustion chamber 5, and the space portion 13 can be easily formed by attaching the flat plate-shaped inclined portion 12 b on the bead 16.

  FIG. 6 is a side view of the secondary air inflow prevention plate 12 according to the third embodiment of the present invention. The secondary air inflow prevention plate 12 increases the strength and absorbs expansion due to heat from the combustion exhaust gas. Thus, a bead 17 for preventing deformation is provided. The bead 17 may be provided on either the horizontal portion 12a or the inclined portion 12b, or may be provided on both.

It is the figure which looked at the combustion apparatus of Example 1 from the side. 1 is a view showing a combustion chamber of Example 1. FIG. It is the figure which showed the flow of the secondary air in a combustion chamber. It is the figure which looked at the combustion chamber of Example 2 from the side. 6 is a view showing a combustion chamber of Example 2. FIG. 6 is a view showing a secondary air inflow preventing plate of Example 3. FIG. It is the figure which looked at the conventional combustion apparatus from the side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body case 2 Blower 3 Burner 5 Combustion chamber 6 Air outlet 11 Secondary air intake hole 12 Secondary air inflow prevention plate 16 Bead

Claims (5)

  A main body case, a burner that burns liquid fuel to generate combustion exhaust gas, a combustion chamber that is provided so as to surround the burner, a blower that introduces air into the main body case, and secondary air from the blower A secondary air intake hole to be taken into the combustion chamber as air; and a substantially L-shaped secondary air inflow prevention plate for preventing the inflow of secondary air to the burner, the secondary air inflow prevention plate and the A liquid fuel combustion apparatus characterized in that a space for allowing a part of the air from the blower to pass therethrough is formed between the front surface of the combustion chamber.   The said secondary air inflow prevention board is provided so that a substantially L-shaped horizontal part may become the same position as the lower end of the said secondary air intake hole, or a low position. Liquid fuel combustion device.   The liquid fuel combustion apparatus according to claim 2, wherein the horizontal portion of the secondary air inflow prevention plate has a length that does not come into contact with the flame.   4. The liquid fuel combustion apparatus according to claim 3, wherein a bead is formed on a front surface of the combustion chamber, and the space portion is formed by the bead and the secondary air inflow prevention plate.   The liquid fuel combustion apparatus according to claim 4, wherein the secondary air inflow prevention plate is attached to a front surface of the combustion chamber so as to absorb thermal expansion.

Images