JP3958754B2 - Cylindrical burner - Google Patents

Description

  The present invention relates to a cylindrical burner used in a spiral water tube heat exchanger or the like.

  Conventionally, as shown in FIG. 1, a helical condensed water pipe 101 and a helical heated water pipe 102 are accommodated in a can 100, and a cylindrical burner A serving as a heat source is disposed in a space surrounded by the heated water pipe 102. A spiral water tube heat exchanger is known. The upstream end of the condensed water pipe 101 is connected to the feed water header 103, the downstream end of the condensed water pipe 101 and the upstream end of the heated water pipe 102 are connected via a relay header 104, and the downstream end of the heated water pipe 102 is connected to a tapping header 105. Is done. An air-fuel mixture of fuel gas and primary air is forcibly supplied to the cylindrical burner A via the manifold B, and the air-fuel mixture burns on the outer peripheral surface of the burner A. The combustion exhaust from the burner A is discharged from the exhaust port 106 at the end of the can body 100 through the arrangement portion of the condensed water pipe 101. Then, the steam in the combustion exhaust is condensed by collecting latent heat by the water flowing through the condensed water pipe 101, and the condensed water is discharged from the drain hole 107 of the can body 100. The water preheated by collecting the latent heat is heated by the combustion flame of the burner A when passing through the heated water pipe 102, becomes hot hot water, and is sent to the outside of the heat exchanger via the hot water header 105. In addition, as shown in FIG. 1, the condensed water pipe | tube 101 and the heating water pipe | tube 102 are formed in the double spiral shape.

  In addition, as a cylindrical burner, conventionally, a combustion cylinder having a number of flame holes established on the peripheral surface, a substrate having an inflow port attached to the proximal end of the combustion cylinder, and a lid attached to the tip of the combustion cylinder It is known that an air-fuel mixture that flows into an internal space of a combustion cylinder from a flow inlet is ejected from a flame hole of the combustion cylinder and burned (see, for example, Patent Document 1). In this case, a combustion cylinder is configured by combining a plurality of ceramic strip-shaped combustion plates having a large number of flame holes into a cylindrical shape.

  Here, the pressure distribution of the air-fuel mixture in the combustion cylinder becomes higher at the front end side of the combustion cylinder, which is the dead end portion of the air-fuel mixture flowing in from the inlet, so that the amount of air-fuel mixture ejected from the combustion cylinder is the proximal end side. As compared with the above, the amount is larger on the tip side, and the axial distribution of the amount of the air-fuel mixture ejected becomes uneven. In this case, a distribution pipe extending in the axial direction from the substrate to the cover plate in the combustion cylinder is provided to partition the space in the combustion cylinder into two chambers, the inner and outer chambers, and air-fuel mixture is introduced into the inner chamber inside the distribution pipe from the inlet. It is conceivable to allow the air-fuel mixture flowing into the inner chamber to flow into the outer chamber outside the distribution tube through a number of distribution holes formed in the distribution tube. According to this, by reducing the distribution density of the distribution holes on the distal end side of the distribution tube, the axial pressure distribution in the outer chamber is made uniform, and the axial distribution of the amount of the air-fuel mixture ejected from the combustion cylinder is uniform. Can be

By the way, the manifold B described above is generally formed in an L shape bent in a direction orthogonal to the axial direction of the combustion cylinder (the radial direction of the combustion cylinder) in order to reduce space. Therefore, the air-fuel mixture flows from the manifold into the inlet with the radial motion component of the combustion cylinder, and the amount of air-fuel mixture ejected from the combustion cylinder increases in the circumferential direction that matches this radial direction. The circumferential distribution of the amount of gas blown becomes uneven.
Japanese Utility Model Publication No. 61-26737

  In the present invention, in view of the above points, even if the air-fuel mixture flows in from the inflow port with a motion component in the radial direction of the combustion cylinder, the amount of the air-fuel mixture ejected from the combustion cylinder in the circumferential direction and the axial direction It is an object of the present invention to provide a cylindrical burner that can make the distribution uniform together and perform uniform combustion over the entire peripheral surface of the combustion cylinder.

  In order to solve the above-mentioned problems, in the present invention, a combustion cylinder having a large number of flame holes opened on the peripheral surface, a substrate having an inflow port attached to the base end of the combustion cylinder, and attached to the tip of the combustion cylinder And a distribution pipe that extends in the axial direction from the substrate to the cover plate and divides the space in the combustion cylinder into two chambers inside and outside, and has an inlet into the inner chamber inside the distribution pipe In a cylindrical burner in which an air-fuel mixture is introduced from the inside, and the air-fuel mixture that has flowed into the inner chamber is caused to flow into the outer chamber outside the distribution tube through a number of distribution holes formed in the distribution tube. An inflow pipe that is connected to the inlet and extends in the axial direction over a position near the distal end of the distribution pipe is disposed, and is positioned on the outer periphery of the distribution pipe at a position that is a predetermined distance from the distal end of the inflow pipe to the proximal end side of the distribution pipe. An annular baffle plate that narrows the gap between the inner peripheral surface of the combustion cylinder and a unit area of the distribution pipe is provided. The opening area of the distribution hole is defined as the distribution hole density, and the portion near the tip of the inflow pipe in the axial range between the front end of the inflow pipe and the front end of the distribution pipe and between the portion and the vicinity of the arrangement position of the baffle plate In the portion, the distribution hole density is set to zero or a minute value near zero.

  According to the present invention, even if the air-fuel mixture flows in from the inlet with the radial motion component of the combustion cylinder, the air-fuel mixture flows with little radial motion component in the process of passing through the inflow pipe. And the circumferential distribution of the amount of air-fuel mixture ejected from the combustion cylinder is made uniform.

  However, since the air-fuel mixture flows from the inlet pipe into the inner chamber at a position close to the tip of the combustion cylinder, the air-fuel mixture pressure in the inner chamber becomes extremely high at the tip, and only by setting the distribution hole density of each part of the distribution pipe, It is difficult to make the axial distribution of the air-fuel mixture pressure in the outer chamber uniform. Here, a part of the air-fuel mixture flowing into the inner chamber from the inflow pipe flows into the outer chamber in the axial range between the front end of the inflow pipe and the front end of the combustion cylinder, and the rest is a distribution pipe on the outer periphery of the inflow pipe. Flows to the proximal end side of the combustion cylinder through the gap between them (the outer peripheral gap of the inflow pipe). In this case, if a distribution hole is formed in a portion near the tip of the inflow pipe in the axial range between the front end of the inflow pipe and the front end of the combustion cylinder (region c in FIG. 4), the outer peripheral gap of the inflow pipe The air-fuel mixture that should flow into the air flows into the outer chamber through the distribution holes in this portion (region c), and the amount of air-fuel mixture that flows into the outer peripheral space of the inflow pipe becomes insufficient. However, in the present invention, the distribution hole density in the portion (c region) near the front end of the inflow pipe in the axial range between the front end of the inflow pipe and the front end of the combustion cylinder is made substantially zero. The air-fuel mixture can be sufficiently supplied to the outer peripheral space of the tube. Therefore, by appropriately setting the distribution hole density in the region from the location where the baffle plate is arranged to the base end of the combustion cylinder, the axial distribution of the mixture pressure in the outer chamber in this region can be made uniform. The axial distribution of the amount of air-fuel mixture ejected from the combustion cylinder in the region can also be made uniform.

  Further, in the axial range between the tip of the inflow pipe and the tip of the combustion cylinder, the air-fuel mixture flows into the outer chamber from a distribution hole in a limited portion other than a portion near the tip of the inflow pipe (c region). . The air-fuel mixture flowing into the outer chamber flows toward the base end side in the outer chamber, but is further restricted from flowing to the base end side by the baffle plate on the outer periphery of the distribution pipe. Note that, in the portion between the tip of the inflow pipe and the position near the location where the baffle plate is located (the area d in FIG. 4), the flow rate of the air-fuel mixture flowing in the outer peripheral space of the inflow pipe is high. The pressure is negative. For this reason, if a distribution hole is formed in a portion (d region) between the tip of the inflow pipe and the position near the location where the baffle plate is disposed, the air-fuel mixture flowing into the outer chamber is sucked into the outer peripheral space of the inflow pipe. End up. However, in the present invention, since the distribution hole density of the portion (d region) between the tip of the inflow pipe and the position near the location where the baffle plate is located is substantially zero, the air-fuel mixture flowing into the outer chamber is It is not sucked into the outer peripheral space of the inflow pipe. Therefore, the pressure distribution of the air-fuel mixture in the portion of the outer chamber between the baffle plate location and the tip of the combustion cylinder can be easily equalized by making the distribution hole density substantially zero and the function of the baffle plate. Is done. As a result, the axial distribution of the amount of air-fuel mixture ejected from the combustion cylinder between the baffle plate location and the tip of the combustion cylinder is made uniform.

  However, if there is a flame hole in the axial position that matches the formation part of the distribution hole in the axial range between the tip of the inflow pipe and the tip of the combustion cylinder (part other than the part near the tip of the inflow pipe), the distribution will be The air-fuel mixture flowing in from the hole goes straight in the radial direction toward the flame hole, and the amount of air-fuel mixture ejected from the flame hole becomes excessive. In this case, the axially leading edge of the flame hole opening range of the combustion cylinder is a portion (c region) near the front end of the inflow pipe in the axial range between the front end of the inflow pipe and the front end of the combustion cylinder or the front end of the inflow pipe. If it is located in the part (d area) between the position where the baffle plate is arranged and the vicinity of the baffle plate, it matches the formation part of the distribution hole in the axial range between the tip of the inflow pipe and the tip of the combustion cylinder. There is no flame hole in the axial position, and the above-mentioned problem does not occur.

  Then, the distribution hole density of the portion other than the portion near the tip of the inflow pipe (c region) in the axial range between the tip of the inflow pipe and the tip of the distribution pipe is measured from the location where the baffle plate is arranged to the tip of the combustion cylinder. By appropriately setting the mixture pressure in the outer chamber in the region of the outer space and the mixture pressure in the outer chamber in the region from the location of the baffle plate to the base end of the combustion tube, the mixture from the combustion tube Can be made uniform over the entire length. Therefore, in combination with the uniform distribution in the circumferential direction of the amount of air-fuel mixture ejected from the combustion cylinder by the action of the inflow pipe, uniform combustion can be obtained over the entire circumferential surface of the combustion cylinder.

  Further, in the portion of the outer chamber near the baffle plate (the region indicated by e in FIG. 4), the pressure of the air-fuel mixture tends to be low. Therefore, the distribution hole density in the portion (e region) in the vicinity of the location where the baffle plate is located is the distribution hole density in the portion (region f in FIG. 4) between the proximal end of the combustion cylinder and the vicinity of the location where the baffle plate is located. It is desirable to make it larger so as to compensate for the pressure drop of the air-fuel mixture in the portion (e region) in the vicinity of the location of the baffle plate in the outer chamber.

  Further, the axial range between the tip of the inflow pipe and the tip of the combustion cylinder is divided into a portion near the tip of the inflow pipe (c region), an intermediate portion (region b in FIG. 4), and a portion near the tip of the combustion cylinder. When the area is divided into three parts (area a in FIG. 4), the air-fuel mixture pressure in the inner chamber becomes very high in the part near the tip of the combustion cylinder (area a). If it is increased, a large amount of air-fuel mixture flows from this portion into the outer chamber, and the amount of air-fuel mixture supplied to the outer peripheral space of the inflow pipe tends to be insufficient. On the other hand, if the distribution pipe density in the portion (a region) near the tip of the combustion cylinder is zero or a minute value near zero, and the distribution holes are concentrated in the intermediate portion (b region), the intermediate portion ( The air-fuel mixture pressure in the inner chamber in (b region) is lower than the portion near the tip of the combustion cylinder (region a), so that the air-fuel mixture does not flow excessively in the outer chamber, and the air-fuel mixture does not flow into the outer peripheral space of the inflow pipe. Can supply enough.

  FIG. 2 shows a cylindrical burner according to an embodiment of the present invention used as a heat source of the spiral water tube heat exchanger of FIG. The burner includes a cylindrical combustion cylinder 1, a substrate 2 attached to the proximal end of the combustion cylinder 1, and a lid plate 3 attached to the distal end of the combustion cylinder 1. As shown in FIG. 3, the combustion cylinder 1 is constituted by combining a plurality of ceramic strip-like combustion plates 1b (six in the illustrated example) having a plurality of flame holes 1a into a cylindrical shape. A distribution tube 4 extending in the axial direction from the substrate 2 to the cover plate 3 is provided in the combustion cylinder 1 as shown in FIG. The distribution tube 4 is formed in a hexagonal cylinder shape similar to the inner surface shape of the combustion cylinder 1, and a large number of distribution holes 4 a are formed on the peripheral surface with a predetermined layout described later.

  The distribution tube 4 is fixed to the substrate 2 at its proximal end by spot welding or the like. A cap 4b is fixed to the distal end of the distribution tube 4, and a convex portion 4c is formed on the cap 4b. The convex portion 4c is inserted into the inner periphery of the annular cover plate 3. When assembling the burner, first, the combustion cylinder 1 is temporarily assembled by combining a plurality of combustion plates 1b into a cylindrical shape. Next, the temporarily assembled combustion cylinder 1 is bound with an appropriate binding tool such as a band so that the combustion plate 1b does not come apart. In this state, the distribution tube 4 is inserted into the combustion cylinder 1 to The base plate 2 is brought into contact with the end face on the base end side through the packing 5, and then the cover plate 3 is brought into contact with the end face on the tip end side of the combustion cylinder 1 through another packing 5. At this time, the convex portion 4 c is inserted into the inner periphery of the lid plate 3. Finally, the convex portion 4c is crushed inward in the axial direction. According to this, the cover plate 3 is caulked and fixed to the distribution tube 4 in a state of being pressed inward in the axial direction, and the combustion cylinder 1 is firmly held between the substrate 2 and the cover plate 3. .

  An annular seat plate 6 that is opposed to the end surface on the front end side of the combustion cylinder 1 is fixed to the substrate 2 by spot welding or the like. Then, cylindrical flange portions 6a and 3a that are bent inward in the axial direction are formed on the outer periphery of the seat plate 6 and the cover plate 3, respectively, so that the packing 5 does not shift in the radial direction.

  The internal space of the combustion cylinder 1 is partitioned by the distribution tube 4 into an inner chamber 7 inside the distribution tube 4 and an outer chamber 8 outside the distribution tube 4. Further, as shown in FIG. 4, the substrate 2 is provided with an inlet 2 a through which an air-fuel mixture of the fuel gas and the primary air that are forcibly supplied from the manifold B flows. The inner chamber 7 is provided with an inflow pipe 9 that extends in the axial direction over the position close to the tip of the combustion cylinder 1 and continues to the inlet 2a. Thus, the air-fuel mixture supplied from the manifold B flows into the inner chamber 7 through the inflow pipe 9, flows into the outer chamber 8 from the inner chamber 7 through the distribution hole 4 a, and from the flame hole 1 a of the combustion cylinder 1. Blow out and burn.

  The inflow pipe 9 converts the air-fuel mixture flowing from the manifold B bent in the radial direction of the combustion cylinder 1 into the inlet 2a with the radial motion component of the combustion cylinder 1 into a flow having almost no radial motion component. It is provided to rectify and flow into the inner chamber 7. By this rectifying action, the circumferential distribution of the amount of air-fuel mixture ejected from the combustion cylinder 1 is made uniform. Here, the distance L <b> 2 between the tip of the inflow pipe 9 and the tip of the combustion cylinder 1 is set within a range of 15 to 35% of the total length L <b> 1 of the combustion cylinder 1. The reason is that if the distance L2 is shorter than this range, the mixture pressure between the tip of the inflow pipe 9 and the tip of the distribution pipe 4 becomes excessive, and the outflow resistance of the mixture from the inflow pipe 9 increases. This is because if the pressure loss of the burner becomes high and the distance L2 becomes longer than the above range, the inflow pipe 9 is insufficient in length and the air-fuel mixture cannot be sufficiently rectified into a flow having no radial motion component. In the present embodiment, in order to increase the rigidity of the cover plate 3, the inner peripheral side portion of the cover plate 3 is recessed inward in the axial direction, and the length of the distribution tube 4 is the same as that of the combustion cylinder 1. It is shorter than the length. Even in this case, if the distance L2 between the tip of the inflow pipe 9 and the tip of the combustion cylinder 1 is about 15% or more of the total length L1 of the combustion cylinder 1, the pressure loss of the burner does not increase to the left.

  On the outer periphery of the distribution tube 4, an annular baffle that is located at a position separated by a predetermined distance L 3 from the distal end of the inflow tube 9 to the proximal end side of the distribution tube 4 and narrows the gap with the inner peripheral surface of the combustion cylinder 1. A plate 10 is provided. The baffle plate 10 preferably narrows the gap between the inner peripheral surface of the combustion cylinder 1 and the outer peripheral surface of the distribution tube 4 (the radial width of the outer chamber 8) to less than half. Assuming that the radial height of H1 is H1 and the gap between the inner peripheral surface of the combustion cylinder 1 and the baffle plate 10 is H2, the ratio H1: H2 between them is set to about 4: 3. The distance L3 is set within a range of 80 to 100% of the distance L2 between the tip of the inflow pipe 9 and the tip of the combustion cylinder 1. The reason will be described later.

  The arrangement pattern of the distribution holes 4 a formed in the distribution pipe 4 is set as follows in relation to the inflow pipe 9 and the baffle plate 10. For convenience of explanation, the axial direction of the combustion cylinder 1 is divided, and the portion near the front end of the combustion cylinder 1 in the axial range between the front end of the combustion cylinder 1 and the front end of the inflow pipe 9 is a region, An intermediate portion of the axial range between the tip and the tip of the inflow tube 9 is a region b, and a portion near the tip of the inflow tube 9 in the axial range between the tip of the combustion cylinder 1 and the tip of the inflow tube 9 is c. The region, the portion between the distal end of the inflow pipe 9 and the vicinity of the location where the baffle plate 10 is arranged is the d region, the portion near the location where the baffle plate 10 is centered is the e region, the e region and the base end of the combustion cylinder 1 A portion between the two is defined as an f region. The distribution holes 4a are formed only in the b region, the e region, and the f region, and the distribution holes 4a are not formed in the a region, the c region, and the d region. In addition, the distribution hole density in the b region and the e region is larger than the distribution hole density in the f region, where the opening area of the distribution hole 4a per unit area of the distribution tube 4 is defined as the distribution hole density. Incidentally, the distribution hole density in each region of a, c, and d is zero. The axial width of each region a, b, c is set to a width obtained by dividing the axial range between the tip of the combustion cylinder 1 and the tip of the inflow pipe 9 into three equal parts, that is, L2 / 3. , The axial width of the region e is also set to L2 / 3.

  A part of the air-fuel mixture flowing into the inner chamber 7 from the inflow pipe 9 flows into the outer chamber 8 through the distribution hole 4a in the region b, and the rest is between the inflow pipe 9 and the distribution pipe 4 in the inner chamber 7. , And flows into the outer chamber 8 from the distribution holes 4a in the e region and the f region. Here, when the distribution hole is formed in the c region, the air-fuel mixture to be introduced into the outer peripheral space of the inflow pipe 9 flows into the outer chamber 8 through the distribution hole of the c region, and the outer peripheral space of the inflow tube 9 The amount of air-fuel mixture flowing into the is insufficient. However, in this embodiment, since the distribution hole 4a is not formed in the region c, the air-fuel mixture can be sufficiently supplied to the outer peripheral space of the inflow pipe 9. Therefore, by appropriately setting the distribution hole density in the region f, the axial distribution of the air-fuel mixture pressure in the outer chamber 8 in the region from the location where the baffle plate 10 is arranged to the proximal end of the combustion cylinder 1 can be made uniform. As a result, the axial distribution of the amount of air-fuel mixture ejected from the flame hole 1a of the combustion cylinder 1 in this region can also be made uniform.

  However, in the portion near the baffle plate 10 in the region from the location where the baffle plate 10 is arranged to the base end of the combustion cylinder 1, the dominant flow of the air-fuel mixture in the outer peripheral space of the inflow pipe 9 is an axial flow. It is difficult for the air-fuel mixture to flow into the outer chamber 8 from the distribution hole 4a, and the air-fuel mixture pressure in the portion of the outer chamber 8 near the location of the baffle plate 10 tends to be low. In the present embodiment, since the distribution hole density in the e region in the vicinity of the location where the baffle plate 10 is arranged is increased, the air-fuel mixture easily flows into the outer chamber 8 from the distribution hole 4a in the e region. A decrease in the air-fuel mixture pressure in the portion near the arrangement position of the plate 10 is effectively compensated.

  The air-fuel mixture flowing into the outer chamber 8 from the distribution hole 4a in the region b flows in the outer chamber 8 toward the proximal end side of the combustion cylinder 1. Here, in the region d, the flow rate of the air-fuel mixture flowing in the outer peripheral space of the inflow pipe 9 is high, and the pressure in the outer peripheral space of the inflow pipe 9 becomes negative. Therefore, if the distribution hole 4 a is formed in the region d, the air-fuel mixture in the outer chamber 8 is sucked into the outer peripheral space of the inflow pipe 9. However, in this embodiment, since the distribution hole 4a is not formed in the d region, the air-fuel mixture flowing into the outer chamber 8 from the distribution hole 4a in the b region is not sucked into the outer peripheral space of the inflow pipe 9, It flows in the outer chamber 8 toward the proximal end side of the combustion cylinder 1. In this case, when the air-fuel mixture flows in the outer chamber 8 as it is to the proximal end, the pressure in the region d of the outer chamber 8 decreases, but the air-fuel mixture may flow further toward the proximal end by the baffle plate 10. Due to the restriction, the pressure distribution of the air-fuel mixture in the portion of the outer chamber 8 between the location where the baffle plate 10 is disposed and the tip of the combustion cylinder 1 is easily made uniform.

  However, if the flame hole 1a exists in the b region, the air-fuel mixture flowing in from the distribution hole 4a in the b region goes straight outward in the radial direction toward the flame hole in the b region, and the air-fuel mixture from the flame hole in the b region. Excessive amount of eruption. Here, at each of the proximal end side and the distal end side of the combustion cylinder 1, it is possible to prevent a flame from coming into contact with the flange portions 3 a and 6 a to generate CO or to deteriorate the flange portions 3 a and 6 a. Therefore, the flame hole 1a is not formed. In the present embodiment, the forefront of the flame hole forming range of the combustion cylinder 1 is positioned in the c region, and the b region is a flameless hole portion where the flame hole 1a does not exist. Therefore, the air-fuel mixture flowing in from the distribution hole 4a in the region b does not travel straight outward in the radial direction and is ejected from the flame hole 1a. Therefore, in combination with pressure equalization by the action of the baffle plate 10, the axial direction of the amount of air-fuel mixture ejected from the flame hole 1 a of the combustion cylinder 1 between the location where the baffle plate 10 is disposed and the tip of the combustion cylinder 1 Distribution is made uniform. Note that the forefront of the flame hole formation range of the combustion cylinder 1 may be positioned in the d region. In addition, blind flame-like dummy flame holes 1c are formed in the flameless holes at the respective ends of the combustion cylinder 1 for molding reasons such as the uniform shrinkage rate during firing of the combustion plate 1b. .

  Here, the portion of the outer chamber 8 between the location where the baffle plate 10 is arranged and the tip of the combustion cylinder 1 and the portion of the outer chamber 8 between the location where the baffle plate 10 is arranged and the base end of the combustion cylinder 1 are complete. However, there is no large pressure difference between the two sides of the baffle plate 10 because the baffle plate 10 and the inner peripheral surface of the combustion cylinder 1 communicate with each other. Then, the distribution hole density in the region b is set so that the air-fuel mixture pressure in the outer chamber 8 in the region from the location where the baffle plate 10 is arranged to the tip of the combustion cylinder 1 and the region from the location where the baffle plate 10 is arranged to the base end of the combustion cylinder 1. If it is appropriately set so that the air-fuel mixture pressure in the outer chamber 8 becomes substantially equal, the axial distribution of the amount of air-fuel mixture ejected from the flame hole 1a of the combustion cylinder 1 can be made uniform over the entire length. Therefore, in combination with the uniform distribution in the circumferential direction of the amount of air-fuel mixture ejected from the flame holes 1a of the combustion cylinder 1 by the rectifying action of the inflow pipe 9, it is uniform over the entire flame hole formation range of the combustion cylinder 1. Can be obtained. In addition, in order to supply the air-fuel mixture to the flame hole 1a existing in the region from the arrangement position of the baffle plate 10 to the tip of the combustion cylinder 1 by the distribution hole 4a in a limited region called the b region, the distribution hole density in the b region Needs to be set larger than the distribution hole density in the f region.

  Incidentally, it is conceivable to form the distribution holes 4a in the b region over the a region. Here, the portion of the region a of the inner chamber 7 is a portion where the air-fuel mixture flowing out in the axial direction from the inflow pipe 9 stops, and the pressure of the air-fuel mixture becomes extremely high. Therefore, if the distribution hole 4a is formed in the region a, a large amount of air-fuel mixture flows into the outer chamber 8 in the region a, and the air-fuel mixture cannot be sufficiently supplied to the outer peripheral space of the inflow pipe 9. In this embodiment, the distribution hole 4a is not formed in the region a, and such a problem does not occur.

  Further, the distance L3 between the front end of the inflow pipe 9 and the baffle plate 10 is set within the range of 80 to 100% of the distance L2 between the front end of the inflow pipe 9 and the front end of the combustion cylinder 1 as described above. The reason is as follows. That is, when the distance L3 is shorter than the above range, a portion where the pressure of the outer peripheral space of the inflow pipe 9 is negatively intruded enters an area between the location where the baffle plate 10 is disposed and the proximal end of the combustion cylinder 1, and this area When the air-fuel mixture pressure in the portion of the outer chamber 8 near the location where the baffle plate 10 is located becomes low, and the distance L3 is longer than the above range, the distance between the location where the baffle plate 10 is placed and the tip of the combustion cylinder 1 This is because the axial length of the portion of the outer chamber 8 becomes too long, and the axial distribution of the mixture pressure in this portion of the outer chamber 8 tends to be uneven.

  In the above embodiment, the distribution holes 4a are not formed at all in the respective regions a, c, and d. However, if the distribution hole density is a minute value near zero, the regions a, c, and d are not formed in these regions. Some distribution holes 4a may be formed. Moreover, although the cylindrical burner of the said embodiment is suitable as a heat source burner of a spiral water tube type heat exchanger, a use is not restricted to this.

The typical cut side view of the spiral water tube type heat exchanger which uses a cylindrical burner as a heat source. The top view of the cylindrical burner of embodiment of this invention. Sectional drawing cut | disconnected by the III-III line | wire of FIG. Sectional drawing cut | disconnected by the IV-IV line of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Combustion cylinder, 1a ... Flame hole, 2 ... Board | substrate, 2a ... Inlet, 3 ... Cover plate, 4 ... Distribution pipe, 4a ... Distribution hole, 7 ... Inner chamber, 8 ... Outer chamber, 9 ... Inflow tube, 10 Baffle plate.

Claims (4)

A combustion cylinder having a large number of flame holes established on the peripheral surface, a substrate having an inlet port attached to the proximal end of the combustion cylinder, a lid plate attached to the tip of the combustion cylinder, and a substrate inside the combustion cylinder And a distribution pipe that extends in the axial direction from the cover plate to partition the space in the combustion cylinder into two chambers inside and outside. In the cylindrical burner in which the air-fuel mixture is allowed to flow into the outer chamber outside the distribution tube through a number of distribution holes formed in the distribution tube,
An inflow pipe that is connected to the inlet and extends in the axial direction over the position near the tip of the combustion cylinder is arranged in the inner chamber, and is spaced a predetermined distance from the tip of the inflow pipe to the proximal end of the distribution pipe on the outer periphery of the distribution pipe. And provided with an annular baffle plate that narrows the gap between the inner peripheral surface of the combustion cylinder,
The opening area of the distribution hole per unit area of the distribution pipe is defined as the distribution hole density. A cylindrical burner characterized in that the distribution hole density is set to zero or a minute value near zero in a portion between the vicinity of the arrangement positions of the two.   The axially leading edge of the flame hole opening range of the combustion cylinder is a portion near the tip of the inflow pipe in the axial range between the front end of the inflow pipe and the front end of the combustion cylinder or the arrangement of the front end of the inflow pipe and the baffle plate The cylindrical burner according to claim 1, wherein the cylindrical burner is located in a portion between the vicinity.   2. The distribution hole density in a portion in the vicinity of the location where the baffle plate is disposed is made larger than the distribution hole density in a portion between the proximal end of the combustion cylinder and the vicinity of the location where the baffle plate is disposed. 2. The cylindrical burner according to 2.   The axial range between the front end of the inflow pipe and the front end of the combustion cylinder is divided into three parts, a part near the front end of the inflow pipe, an intermediate part, and a part near the front end of the combustion cylinder. The cylindrical burner according to any one of claims 1 to 3, wherein the distribution hole density in the close portion is set to zero or a minute value near zero, and the distribution holes are concentrated in the intermediate portion. .

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