TW202200935A - Gas nozzle and combustion device capable of reducing the number of punching and lowering the costs as much as possible - Google Patents

Abstract

The present invention provides a gas nozzle (31) formed by punching a plate material for supplying the fuel gas to a burner, comprising a cylindrical nozzle body (311) having an inner space (311a) into which the fuel gas flows; and an end wall (312) located on the side opposite to the base end of the nozzle body (311) on the inflow side of the fuel gas, wherein a nozzle hole (313) is formed on the end wall (312) for ejecting the fuel gas flowing into the inner space (311a) of the nozzle body (311). For the gas nozzle (311), even if the tensile depth of the nozzle body (311) is shallow, the combustion performance can be stabilized and the generation of flute sound can be suppressed. The base of the nozzle hole (313) located on the inner space (311a) side of the nozzle body (311) is provided with an expanding department (313a) whose hole diameter gradually expands toward the inner space (311a). Preferably, the distance (L) from the base end of the nozzle body (311) to the end wall (312) is set to a distance that can be stretched and formed by one punching process, thereby reducing the number of punching and lowering the costs as much as possible.

Description

Gas nozzles and combustion devices

The present invention relates to a gas nozzle for supplying fuel gas to a burner, and a combustion apparatus using the gas nozzle.

In the prior art, as such a gas nozzle, one formed by pressing a plate material is known (for example, refer to Patent Document 1). This gas nozzle includes: a cylindrical nozzle body having an inner space into which fuel gas flows; and an end wall portion located on the opposite side to the base end of the nozzle body which is the inflow side of the fuel gas. The end wall portion is formed with a nozzle hole for ejecting the fuel gas that has flowed into the inner space. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2004-197971

[The problem to be solved by the invention]

In addition, if the thickness of the plate material used as the material of the gas nozzle is reduced in order to reduce the cost, when the drawing depth of the nozzle body due to the press working is made deep, it is easy to cause chipping. crack. Therefore, when the nozzle body is formed by press working of a thin plate material, the drawing depth of the nozzle body has to be made shallow.

However, in this case, the flow system of the fuel gas in the inner space of the nozzle body is not sufficiently rectified. As a result, the combustion performance becomes unstable, and a so-called "pipe sound generation" problem is likely to occur.

In view of the above-mentioned problems, the present invention aims to provide a gas nozzle capable of suppressing the occurrence of flute noise, and a gas nozzle using the gas nozzle with stable combustion performance even if the nozzle body has a shallow drawing depth The burner of the nozzle is a subject. [means to solve the problem]

In order to solve the above-mentioned problems, the first invention of the present application is a gas nozzle formed by press working of a plate material for supplying fuel gas to a burner, and comprising: a cylindrical nozzle body having a fuel gas The inner space into which the gas flows; and the end wall portion, which is located on the opposite side from the base end of the nozzle body, which is the inflow side of the fuel gas, and the end wall portion is formed so that the inflow into the inside of the nozzle body is formed. The nozzle hole for the fuel gas in the space to be ejected is characterized in that: at the base of the nozzle hole located at the inner space side of the nozzle body, it is provided with a diffuser whose hole diameter gradually expands as it goes toward the inner space of the nozzle body. diameter.

In addition, the second invention of the present application is a combustion apparatus including a burner and a heat exchanger heated by combustion gas from the burner, and the combustion apparatus is characterized by: : As the gas nozzle for supplying the fuel gas to the burner, the gas nozzle of the above-mentioned first invention is used.

According to the present invention (first invention), even if the drawing depth of the nozzle body is shallow, the flow of the fuel gas in the inner space of the nozzle body is not sufficiently rectified, and the diameter of the base of the nozzle hole is enlarged At the same time, the flow of fuel gas is also rectified. As a result, the combustion performance is stable, and the occurrence of "pipe sound" can also be suppressed.

Further, in the present invention, it is preferable that the enlarged diameter portion is formed so that the enlargement rate of the hole diameter gradually increases toward the inner space of the nozzle body. According to this, compared with the case where the enlarged diameter portion is formed so that the enlargement rate of the hole diameter becomes constant, the distance that the fuel gas ejected from the nozzle hole is maintained at a high speed and reaches becomes longer, and furthermore , the inflow of air from the outside to the nozzle hole is reduced.

Further, in the present invention, even if the drawing depth of the nozzle body is shallow, the performance is not deteriorated. Therefore, the drawing depth of the nozzle body, that is, the distance from the base end of the nozzle body to the end wall portion can be set to a distance that can be drawn and formed by one press working. According to this, the number of stamping processes can be reduced, and the cost can be reduced as much as possible.

Referring to FIGS. 1 and 2 , a combustion apparatus according to an embodiment of the present invention (the second invention) is provided with a combustion frame 1 and a plurality of burners 2 arranged side by side in the lower part of the combustion frame 1 , and a manifold 3 for supplying fuel gas to these burners 2, and a heat exchanger 4 arranged at the upper part of the combustion frame 1 and heated by the combustion gas from the burner 2 .

Taking the side-by-side arrangement direction of the burners 2 as the horizontal direction, each burner 2 has a flame port at the upper end that is "slender in the front-rear direction in the horizontal direction perpendicular to the horizontal direction". The flat burner of the part. At the lower part of each burner 2, a mixing pipe part 21 is provided. At the front end of the mixing pipe portion 21, an inflow port 22 opened in the front is provided. In addition, it is configured such that the fuel gas ejected from the respective gas nozzles 31, which will be described later, from the manifold 3 flows into the inflow ports 22 of the respective combustors 2, and the primary air flows into the inflow ports 22, and the mixture is mixed. At the pipe portion 21 , a mixed gas of fuel gas and primary air is generated, and the mixed gas system is ejected from the flame port of the burner 2 and burned.

Referring also to FIG. 3 , at the front portion of the bottom plate 11 of the combustion frame body 1 , a stepped portion 111 that rises upward is formed. An opening 112 facing the inflow port 22 of the mixing pipe portion 21 of each burner 2 is opened at the step portion 111 . In the present embodiment, since six burners 2 are arranged side by side, six openings 112 are arranged side by side in the lateral direction. In addition, the bottom plate 11 is formed with a plurality of dimples 113 , which are recessed upward and "enclose the lower edge of each burner 2 from both sides in the lateral direction". Further, on the front plate 12 of the combustion frame 1, an electrode part 5 is mounted, and the electrode part 5 is provided with an ignition electrode 51 for igniting the burner 2 and for detecting the flame of the burner 2. Measured flame rod 52.

The heat exchanger 4 is a fin-and-pipe type heat exchange including a plurality of heat-absorbing fins 41 stacked in the lateral direction and a plurality of heat-absorbing pipes 42 penetrating the heat-absorbing fins 41 constituted by the device. These heat-absorbing pipes 42 are connected in series by a plurality of connecting pipes 43 bent in a U-shape on the outer surface of the upper part of the combustion frame 1 . Also, the heat absorption pipe 42 at the upstream end is connected to the water supply pipe 44 , and the heat absorption pipe 42 at the downstream end is connected to the hot water outlet pipe 45 .

A fan 7 is connected to the upper end of the combustion frame 1 via the exhaust hood 6 . At the fan 7, a fan motor 71 is additionally provided. The combustion gas after passing through the heat exchanger 4 is sucked by the fan 7 . The combustion gas sucked into the fan 7 is discharged to the outside through an exhaust pipe (not shown) connected to the outlet 72 of the fan 7 . Also, as shown in FIG. 3 , a large number of small holes 114 are formed in the bottom plate 11 of the combustion frame 1 . Then, the combustion air system is supplied to each burner 2 by the suction force of the fan 7 . That is, the air sucked from the inflow port 22 through each opening 112 is supplied to each burner 2 as primary air for combustion, and the air sucked from the small hole 114 is used as the primary air for combustion. Secondary air for combustion is supplied to each burner 2 .

At the lower front ends of the side plates 13 on both sides of the combustion frame 1 in the lateral direction, tongue pieces 131 protruding further forward than the stepped portions 111 of the bottom plate 11 are provided. In addition, the manifold 3 is fixed to the tongue portion 131 by screws 34a at the fixing portions 34 provided at the ends on both sides in the lateral direction.

Referring to FIGS. 4 to 6 , the manifold 3 is formed by protruding a plurality of (six in this embodiment) “mixing pipes toward each burner 2 ” corresponding to the plurality of burners 2 . The manifold body 3a of the gas nozzle 31 according to the embodiment of the present invention (the first invention) for injecting the fuel gas through the inlet 22 of the portion 21, and the distribution chamber for dividing the fuel gas between itself and the manifold body 3a 32 of the cover 3b, and constitute it. The cover 3b is fastened to the peripheral portion thereof, and is seam welded with the manifold body 3a. The manifold 3 is further provided with an inflow port 33 . The above-mentioned fixing portion 34 and the inflow port 33 are provided at the manifold body 3a. The fuel gas flows into the inflow port 33 via the valve unit 8 connected thereto. The fuel gas flowing in from the inflow port 33 is distributed to each gas nozzle 31 via the distribution chamber 32 , and is ejected from each gas nozzle 31 toward the inflow port 22 of the mixing pipe portion 21 of each burner 2 .

The manifold body 3a is formed by press working of a plate material such as a stainless steel plate having a relatively thin plate thickness. In addition, the cover 3b is also formed by stamping a plate material thinner than the material of the manifold body 3a. Of course, each of the gas nozzles 31 protruding from the manifold body 3a is formed by pressing the plate material that is the material of the manifold body 3a. As shown in FIG. 6, each gas nozzle 31 is provided with: a cylindrical nozzle body 311 having an inner space 311a into which the fuel gas flows from the distribution chamber 32; The side opposite to the base end of the nozzle body 311 which is the inflow side of the fuel gas. The end wall portion 312 is formed with a nozzle hole 313 through which the fuel gas flowing into the inner space 311a of the nozzle body 311 is ejected.

Here, in order to reduce the cost, if the plate material of the gas nozzle 31, that is, the plate material of the manifold body 3a, is reduced in thickness, the nozzle body 311 will be stretched by pressing. When the depth is set to be deep, the system is likely to be cracked. Therefore, in the case of forming the gas nozzle 31 by pressing a thin plate material, the drawing depth of the nozzle body 311 has to be made shallow. In particular, in order to reduce the cost as much as possible, it is preferable to set the drawing depth of the nozzle body 311, that is, the distance L from the base end of the nozzle body 311 to the end wall portion 312, to be able to use 1 A small distance for drawing and forming by secondary stamping. For example, when the plate material that is the material of the manifold body 3a is a stainless steel plate (SUS304) with a plate thickness of 1.2 mm, the above-mentioned distance L that can be stretched by one press working is It becomes about 4mm. However, in this case, in the inner space 311a of the nozzle body 311, the flow system of the combustion gas is not sufficiently rectified, and the combustion performance becomes unstable or a so-called "blowing" easily occurs. flute" and the like.

Therefore, in the present embodiment, at the base of the nozzle hole 313 located on the side of the inner space 311a of the nozzle body 311, an enlarged diameter portion is provided whose hole diameter gradually expands toward the inner space 311a of the nozzle body 311 313a. Here, in the gas nozzle 31 of the first embodiment shown in FIG. 6, the diameter-expanding portion 313a is based on the expansion ratio of the diameter of the hole (the unit will be in the direction of the hole axis from the place where the hole diameter is R). The hole diameter at the place where the length ΔD is separated is set as R+ΔR, and the value expressed by ΔR/ΔD) becomes constant, that is, the hole diameter expands linearly toward the inner space 311a of the nozzle body 311 way of being formed. On the other hand, in the gas nozzle 31 according to the second embodiment shown in FIG. 7 , the enlarged diameter portion 313a is such that the enlargement rate of the hole diameter gradually increases toward the inner space 311a of the nozzle body 311, and also That is, it is formed so that the aperture diameter may expand in a curvilinear shape toward the inner space 311a.

Regardless of the configuration, it is the same, if the enlarged diameter portion 313a is provided at the base of the nozzle hole 313, even if the flow of the fuel gas in the inner space 311a of the nozzle body 311 is not sufficiently rectified, by the enlarged diameter portion 313a. In the diameter portion 313a, the flow of the fuel gas is also rectified. As a result, the combustion performance is stable, and the occurrence of "pipe sound" can also be suppressed.

In order to confirm the above effects, simulations were performed using fluid analysis software. As conditions, the distance L from the base end of the nozzle body 311 to the end wall portion 312 was set to 4 mm, the plate thickness of the end wall portion 312 was set to 0.8 mm, and the diameter of the nozzle hole 313 was set to 1.5 mm mm, and the supply gas pressure to the gas nozzle 31 was set to 1.0 kPa. In the gas nozzle 31 of the first embodiment in which the enlarged diameter portion 313a that linearly expands the hole diameter at an angle of 45° is provided within 0.2 mm of the base of the nozzle hole 313, the fuel gas is ejected. The velocity profile becomes as shown in FIG. 8 . In addition, in the gas nozzle 31 of the second embodiment, in the gas nozzle 31 of the second embodiment in which the enlarged diameter portion 313a that expands the hole diameter in a curved shape with a radius of curvature of 1.0 mm is provided within a range of 0.55 mm from the base of the nozzle hole 313, the fuel The gas ejection velocity distribution becomes as shown in FIG. 9 . On the other hand, in the gas nozzle 31 ′ of the comparative example in which the enlarged diameter portion of the base of the nozzle hole 313 is omitted, the distribution of the ejection velocity of the fuel gas is as shown in FIG. 10 . In addition, in Figs. 8 to 10, the speed of the outer part of line a is 0 to 4.5 m/sec, the speed of the part between line a and line b is 4.5 to 9.0 m/sec, and the speed of line b and line c is 4.5 to 9.0 m/sec. The speed of the part between the lines is 9.0～13.5m/s, the speed of the part between the c-line and the d-line is 13.5-18.0m/s, the speed of the part between the d-line and the e-line is 18.0 ～22.5m/s, the speed of the part between e-line and f-line is 22.5～27.0m/s, the speed of the part between f-line and g-line is 27.0～31.5m/s, g-line and h-line The speed of the part between the lines is 31.5～36.0m/s, the speed of the part between the h line and the i line is 36.0～40.5m/s, the speed of the inner part of the i line is 40.5～45.0m/s second.

In the gas nozzle 31 of the present invention (both embodiments of the first and second), the fuel gas ejected from the nozzle hole 313 is maintained at a faster speed than the gas nozzle 31' of the comparative example. reach further. If the area where the flow velocity of the ejected gas is high reaches far away in this way, the force for feeding the primary air into the inlet 22 of the mixing pipe portion 21 of the burner 2 increases, and the combustion performance becomes stable. . In addition, the part between the hole wall surface of the nozzle hole 313 and the a-line is the part where air flows into the nozzle hole 313 from the outside. In the gas nozzle 31 of the present invention, the portion between the hole wall surface of the nozzle hole 313 and the line a is narrower than that of the gas nozzle 31 ′ of the comparative example, and the air from the outside of the nozzle hole 313 is narrow. The inflow system is reduced. Since the inflow of air from the outside into the nozzle hole 313 causes the generation of the whistle sound, the gas nozzle 31 of the present invention suppresses the generation of the whistle sound.

In addition, the distance to which the fuel gas ejected from the nozzle hole 313 is maintained at a high speed is longer in the gas nozzle 31 of the second embodiment than that of the gas nozzle 31 of the first embodiment. Furthermore, although it is not clearly shown in FIG. 9 , the inflow of air from the outside into the nozzle holes 313 is based on the gas nozzle 31 of the second embodiment as compared to the gas nozzle 31 of the first embodiment. less.

As mentioned above, although the embodiment of the present invention has been described with reference to the drawings, the present invention is not limited to this. For example, in the above-described embodiment, the inventors applied the present invention to the plurality of gas nozzles 31 provided in the manifold 3, but the same can be applied to the gas nozzles provided individually. this invention.

2: Burner 31: Gas nozzle 311: Nozzle body 311a: Interior Space 312: end wall 313: Nozzle hole 313a: Expansion part L: The distance from the base end of the nozzle body to the end wall 4: heat exchanger

Fig. 1 is a perspective view of a combustion apparatus according to an embodiment of the present invention (second invention). [ Fig. 2 ] It is a cut side view taken along II-II of Fig. 1 . [ Fig. 3 ] It is a perspective view which is viewed obliquely from below in a state where the manifold of the combustion device of the embodiment is separated. [ Fig. 4] Fig. 4 is a perspective view of a manifold provided with a gas nozzle according to an embodiment of the present invention (first invention), viewed obliquely from the rear. [ Fig. 5] Fig. 5 is a perspective view viewed obliquely from the front in a state in which the manifold body and the cover of the manifold of Fig. 4 are separated. Fig. 6 is an enlarged cross-sectional view of the gas nozzle according to the first embodiment of the present invention, cut along the line VI-VI of Fig. 4 . Fig. 7 is an enlarged cross-sectional view corresponding to Fig. 6 of the gas nozzle according to the second embodiment of the present invention. [ Fig. 8] Fig. 8 is a graph showing the injection velocity distribution of the fuel gas at the gas nozzle according to the first embodiment of the present invention. Fig. 9 is a graph showing the injection velocity distribution of the fuel gas at the gas nozzle according to the second embodiment of the present invention. [ Fig. 10 ] is a graph showing the injection velocity distribution of the fuel gas at the gas nozzle of the comparative example.

3: Manifold

3a: Manifold body

3b: Cover

31: Gas nozzle

32: Distribution Room

311: Nozzle body

311a: Interior Space

312: end wall

313: Nozzle hole

313a: Expansion part

L: The distance from the base end of the nozzle body to the end wall

Claims (4)

A gas nozzle is a gas nozzle formed by stamping a plate material for supplying fuel gas to a burner, and is provided with: a cylindrical nozzle body having an inner space into which the fuel gas flows; and The end wall portion is located on the opposite side from the base end of the nozzle body which is the inflow side of the fuel gas, At the end wall portion, a nozzle hole for ejecting the fuel gas flowing into the inner space of the nozzle body is formed, The gas nozzle is characterized by: At the base of the nozzle hole positioned at the inner space side of the nozzle body, an enlarged diameter portion is provided that gradually enlarges the hole diameter as it goes toward the inner space of the nozzle body. The gas nozzle as recited in claim 1, wherein, The enlarged diameter portion is formed so that the enlargement rate of the hole diameter gradually increases toward the inner space of the nozzle body. The gas nozzle as claimed in claim 1 or 2, wherein, The distance from the base end of the nozzle body to the end wall portion is set to a distance that can be stretched by one press working. A burner is provided with a burner and a heat exchanger heated by combustion gas from the burner, The combustion device is characterized by: As the gas nozzle for supplying the fuel gas to the burner, the gas nozzle described in any one of Claims 1 to 3 is used.

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