Premixing device and combustion device comprising same

Abstract

The invention provides a premixing device and a combustion device including the premixing device, which can improve the regulation ratio through components with a simple structure while minimizing defects such as increase of pressure loss and the like as much as possible. This premixing device is provided with: a blade part which is disposed at a midway position in a gas flow path through which air flows, and in which a fuel gas outlet is provided in a region close to one end on the downstream side in the direction of air flow; and a pair of divided flow paths configured in a state in which a portion of the gas flow path is divided by the blade portion, the premixing device further comprising a tab-shaped or step-shaped baffle portion located on the upstream side of the fuel gas outlet in the direction of air flow in the inner circumferential surface of each divided flow path, the baffle portion is provided in at least a portion of the inner region of each of the divided flow paths, and is capable of making the flow rate of air flowing in the outer region of each of the divided flow paths faster than the flow rate of air passing through the inner region.

Description

Technical Field

[0001] The present invention relates to a premixing device and a combustion device including the same. Here, the term "premixing" refers to a process of premixing air and fuel gas to generate a combustible mixed gas for the purpose of premixing combustion. Background Art

[0002] As an example of a premixing device, there is Fig.11 The pre-mixing device shown. Fig.11 This is the same as Patent Document 1 Figure 6 The corresponding structure of (c).

[0003] The premixing device Ae shown in the figure is provided with a blade portion 41a in the gas flow path 3a for the air supplied from the outside to flow. The blade portion 41a extends in a direction perpendicular to the paper surface of the figure, and at the position where the blade portion 41a is provided, the gas flow path 3a is divided into a pair of divided flow paths 30a sandwiching the blade portion 41a. A fuel gas outlet 80a is provided in a region of one end of the blade portion 41a close to the downstream side in the air flow direction.

[0004] With such a structure, the negative pressure generated by the flow of air through the gas flow path 3a can be used to cause the fuel gas to flow out from the fuel gas outlet 80a into the gas flow path, thereby generating a mixed gas of the fuel gas and air.

[0005] However, according to the premixing device Ae, there is room for improvement as described below.

[0006] That is, the air flowing into the gas flow path 3a branches and flows in a pair of segmented flow paths 30a, and then merges in the downstream area of ​​the air flow direction of the blade portion 41a and the adjacent position of the fuel gas outlet 80a. According to this flow of air (the confluence), it is difficult to generate negative pressure in the adjacent position of the fuel gas outlet 80a, and it is impossible to make an appropriate amount of fuel gas flow out from the fuel gas outlet 80a into the gas flow path 3a, and the outflow amount tends to be insufficient. As a result, the generated mixed gas becomes an inappropriate mixture ratio with a lean fuel, which is not preferred in terms of improving the turndown ratio. This undesirable situation becomes more significant when the total air flow rate flowing in the gas flow path 3a is small and the air flow rate becomes low, making it difficult to generate a strong negative pressure.

[0007] As a method for eliminating the above-mentioned disadvantages, it is considered to reduce the opening area (flow path area) of a pair of divided flow paths 30a to increase the flow rate of air. However, if only this method is adopted, the flow path resistance of each divided flow path 30a becomes large, resulting in the disadvantage of increased pressure loss.

[0008] [Prior art literature]

[0009] [Patent Document]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2022-99650

[0011] [Patent Document 2] Japanese Patent Publication No. 62-35010

[0012] [Patent Document 3] Japanese Patent Publication No. 2003-130312

[0013] [Patent Document 4] Japanese Patent No. 3686487

[0014] [Patent Document 5] Japanese Patent Application Publication No. 2022-3283 Summary of the invention

[0015] [Problems to be solved by the invention]

[0016] The present invention was made under the above circumstances, and an object of the present invention is to provide a premixing device capable of improving the turndown ratio by using components with a simple structure while minimizing disadvantages such as an increase in pressure loss, and a combustion device including the premixing device.

[0017] [Technical means to solve the problem]

[0018] In order to solve the above-mentioned problems, the present invention adopts the following technical means.

[0019] The premixing device provided by the first aspect of the present invention comprises: a gas flow path forming member, in which a gas flow path for circulating air supplied from the outside is formed; a blade portion, which is arranged in the middle of the gas flow path, and a fuel gas flow outlet is provided in a region close to one end on the downstream side of the air flow direction, the fuel gas flow outlet can use the negative pressure generated by the flow of the air to make the fuel gas flow out to the gas flow path; and a pair of segmented flow paths, which are configured in a state in which a part of the gas flow path is divided by the blade portion, and the blade portion is sandwiched in the x direction intersecting the air flow direction. The blade portion is arranged on both sides thereof, and the premixing device is characterized in that it also includes a protruding sheet or stepped baffle portion, and the protruding sheet or stepped baffle portion is located on the inner circumferential surface of each divided flow path, which is closer to the upstream side of the air flow direction than the fuel gas outflow port, and protrudes toward the inner direction of each divided flow path. The baffle portion is arranged on at least a part of the inner area on the side of the blade portion in each divided flow path, and is constructed to make the flow velocity of air flowing in the outer area on the opposite side of the inner area in each divided flow path faster than the flow velocity of air passing through the inner area.

[0020] According to this structure, the following effects can be obtained.

[0021] First, through the action of the baffle portion, the flow rate of the air flowing through the outer area of ​​each segmented flow path and in the area away from the fuel gas flow outlet becomes faster. Therefore, it is possible to suppress the phenomenon that the air flowing in the pair of segmented flow paths branches and merges at the opposite positions near the fuel gas flow outlet, that is, hindering the fuel gas from flowing out of the fuel gas flow outlet to the gas flow path. As a result, according to the present invention, although the negative pressure generated by the air flow acting on the fuel gas flow outlet is reduced compared with the past, based on the above-mentioned action, in general, the amount of fuel gas flowing out of the fuel gas flow outlet to the gas flow path can be increased compared with the prior art. Therefore, according to the present invention, even if the air flow in the gas flow path decreases and the air flow rate becomes low, an appropriate amount of fuel gas corresponding to the air flow rate can be made to flow out to the gas flow path, suppressing the inappropriate mixing ratio of the mixed gas to be fuel-lean, and improving the adjustment ratio.

[0022] On the other hand, in the present invention, since a baffle portion is provided on the inner circumference of each segmented flow path, the opening area (flow path area) of each segmented flow path is narrowed accordingly compared to a case where this is not the case. The baffle portion is a protruding sheet or step-shaped portion that protrudes from the inner circumference of each segmented flow path toward the inner side thereof, and the inner diameter of the length dimension area of ​​each segmented flow path is not formed into a small diameter, so the increase in flow path resistance of each segmented flow path can also be suppressed. In addition, the baffle portion only needs to be provided in the inner area on the blade side of each segmented flow path, and does not need to be provided across the entire circumference of the inner circumference of each segmented flow path, so the increase in flow path resistance of each segmented flow path (gas flow path) can be further suppressed. Therefore, the pressure loss associated with air flow can also be reduced.

[0023] In the present invention, it is preferable that the baffle portion is provided so as to avoid at least a part of the outer region in each of the divided flow paths.

[0024] According to this structure, the effect of preventing the increase of the flow resistance of each divided flow path (gas flow path) and the effect of accelerating the flow rate of the air flowing in the outer area of ​​each divided flow path can be made better. That is, for example, unlike the above structure, in the case where the baffle portion is set in the entire area of ​​the outer area in addition to the inner area of ​​each divided flow path, the opening area (flow path area) of each divided flow path becomes quite small, and there is a disadvantage of increased flow resistance. In addition, the baffle portion set in the outer area has almost no effectiveness in obtaining the effect of accelerating the flow rate of the air flowing in the outer area of ​​each divided flow path, but instead acts disadvantageously. In contrast, according to the above structure, this disadvantage can be appropriately avoided.

[0025] In the present invention, it is preferred that the baffle portion has an air-receiving surface facing upstream in the air flow direction, and is constructed so that air can collide with the air-receiving surface to generate a vortex of the air, and the air moves toward the air-receiving surface and from a position upstream in the air flow direction along the inner circumferential surface of each divided flow path.

[0026] According to this structure, an air vortex can be generated in the area on the upstream side of the air receiving surface of the baffle portion in the air flow direction, but the vortex itself does not flow at high speed toward the downstream side in the air flow direction in each divided flow path. Therefore, it is effective in slowing down the flow rate of the air flowing in the inner area of ​​each divided flow path. Therefore, it is more effective to suppress the phenomenon that the air flowing in the pair of divided flow paths respectively branches and flows at the positions near the fuel gas flow outlet facing each other.

[0027] In the present invention, it is preferred that, when observing the air flow direction in the gas flow path, the inner circumferential surface of each divided flow path includes a pair of first areas, the pair of first areas are adjacent to the blade portion and are separated and face each other in the y direction intersecting the x direction, and as the baffle portion, a baffle portion is included that is arranged in at least one of the pair of first areas, and the front end edge of the baffle portion is inclined in such a manner that the closer it is to the blade portion in the x direction, the closer it is to the center of the each divided flow path in the y direction.

[0028] According to this structure, the baffle portion with an inclined front edge can be used to make the air flowing in the inner area of ​​each divided flow path flow toward the outer area side (also refer to the use of the baffle portion described later). Figure 5A to Figure 5D As a result, it is possible to more thoroughly suppress the phenomenon in which the air that branches and flows in the pair of divided flow paths merges at the positions near the fuel gas outflow port that face each other.

[0029] The premixing device provided by the second aspect of the present invention includes: a gas flow path forming member, in which a gas flow path for circulating air supplied from the outside is formed; a blade portion, which is arranged in the middle of the gas flow path, and a fuel gas flow outlet is provided in an area close to one end on the downstream side of the air flow direction, and the fuel gas flow outlet can utilize the negative pressure generated by the flow of the air to make the fuel gas flow out to the gas flow path; and a pair of divided flow paths, which are constructed in a state in which a part of the gas flow path is divided by the blade portion, and are arranged on both sides of the blade portion in the x direction intersecting the air flow direction. The premixing device is characterized in that, as the fuel gas flow outlet, it includes a pair of fuel gas flow outlets, and the pair of fuel gas flow outlets are provided with openings on both side surface portions of the area of ​​the blade portion close to the one end, and face each other with the downstream side areas of the air flow direction of the pair of divided flow paths.

[0030] According to this structure, the following effects can be obtained.

[0031] That is, before the air flowing through the pair of split flow paths branches off and merges with each other in a direction downstream of the blade portion in the air flow direction, the negative pressure generated by the flow of the air can act on the pair of fuel gas outlets. Therefore, even when the air flow in the gas flow path decreases and the air flow rate becomes low, an appropriate amount of fuel gas corresponding to the air flow can flow out to the gas flow path, suppressing the inappropriate mixing ratio of the mixed gas to be fuel-lean, and improving the regulation ratio. On the other hand, there is no need to narrow the opening area (flow path area) of each split flow path, so the pressure loss related to the air flow can also be reduced.

[0032] In the present invention, a configuration in which the characteristic configuration of the premixing device provided by the first aspect of the present invention and the characteristic configuration of the premixing device provided by the second aspect of the present invention are combined can be adopted.

[0033] According to such a structure, a more preferable effect can be obtained in solving the problem of the present invention.

[0034] In the present invention, it is preferred that the fuel gas flow outlet includes a pair of fuel gas flow outlets, and the pair of fuel gas flow outlets are arranged with openings on both side surfaces of the area of ​​the blade portion close to the one end, and face to face with the downstream side areas of the air flow direction of each of the pair of divided flow paths.

[0035] According to this structure, before the air flowing through the pair of split flow paths respectively moves to the downstream side of the air flow direction of the blade portion and merges with each other, the negative pressure generated by the flow of the air can be applied to the pair of fuel gas outlets respectively. Therefore, even when the air supply flow rate to the gas flow path is small, it can be more reliably realized that an appropriate amount of fuel gas corresponding to it flows out to the gas flow path.

[0036] In the present invention, it is preferred that the gas flow path and the fuel gas flow outlet are respectively the first gas flow path and the first fuel gas flow outlet, and the premixing device also includes: a second gas flow path, which is arranged in the gas flow path forming component in a state of being separated from the first gas flow path via a partition wall portion; an air inlet portion, which is arranged in the gas flow path forming component so that the air supplied from the outside can be branched and move to the first gas flow path and the second gas flow path respectively; a second fuel gas flow outlet, which can utilize the negative pressure generated by the flow of the air in the second gas flow path to make the fuel gas flow out to the second gas flow path; and a partition, which can close the second gas flow path when the total air flow rate of the first gas flow path and the second gas flow path is less than a specified value, so that the air flows only in the first gas flow path of the first gas flow path and the second gas flow path.

[0037] According to this structure, the following effects can be obtained.

[0038] That is, when the air flow rate in the gas flow path is more than the prescribed amount, the partition can be set to an open state, and the air can be circulated in both the first gas flow path and the second gas flow path (first form). In the first form, the fuel gas can flow out from both the first fuel gas outlet and the second fuel gas outlet, and the appropriate amount of fuel gas corresponding to its flow rate can be appropriately mixed in the air. On the other hand, in contrast, when the air flow rate in the gas flow path is small and less than the prescribed amount, the partition can be set to a closed state, and the air does not flow in the second gas flow path (second form). In the second form, the fuel gas can flow out only from the first fuel gas outlet relative to the air flowing in the first gas flow path, thereby reducing the outflow of the fuel gas. In the present invention, when the second form is set, when the air flow rate in the first gas flow path is quite small, the outflow of the fuel gas can be promoted by the action based on the action of the blade portion (suppressing the confluence of the air at the opposite nearby position of the first fuel gas outlet). Therefore, according to the structure, it is more preferable in terms of improving the adjustment ratio.

[0039] The combustion device provided by the third aspect of the present invention includes: a premixing device that generates a mixed gas of air and fuel gas; and a burner unit that receives the supply of the mixed gas from the premixing device and burns the fuel gas. The combustion device is characterized in that, as the premixing device, the premixing device provided by the first aspect of the present invention is used.

[0040] According to such a structure, the same effects as those described above with respect to the premixing device provided by the first aspect of the present invention can be obtained.

[0041] Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic explanatory diagram showing an example of a combustion device including the premixing device of the present invention.

[0043] Figure 2 yes Figure 1 A three-dimensional diagram of the appearance of the pre-mixing device.

[0044] Figure 3 yes Figure 2 Exploded three-dimensional diagram.

[0045] Figure 4A yes Figure 1 to Figure 3 The front cross-sectional view of the premixing device shown in FIG. Figure 5A IVa-IVa section of the Figure 4B yes Figure 4A IVb-IVb cross-section diagram, Figure 4C Yes means Figure 4A The diaphragm portion in the closed state shown is a front cross-sectional view of the structure when it is in the open state.

[0046] Figure 5A yes Figure 1 to Figure 4C A plan view of a gas flow path forming member of a premixing device shown in FIG. Figure 5B yes Figure 5A The enlarged view of the Vb part, Figure 5C yes Figure 5B A partial cross-sectional plan view of Figure 5D is Figure 5C The structure shown is a partially sectional plan view in which the baffle portion is omitted.

[0047] Figure 6 yes Figure 5A VI-VI cross-sectional view.

[0048] Figure 7 yes Figure 1 to Figure 3 The front cross-sectional view of the premixing device shown in FIG. Figure 5A VII-VII section of the figure).

[0049] Fig. 8A yes Figure 1 to Figure 7 FIG. 1 is a diagram for explaining the function of the baffle portion of the embodiment shown in FIG. Figure 8B This is a diagram illustrating the effect of proportion.

[0050] Fig. 9A , Fig. 9B is another example of the present invention. Fig. 9A is a partial cross-sectional plan view of a gas flow path forming member, Fig. 9B yes Fig. 9A IXb-IXb cross-sectional view.

[0051] Fig. 10A , Fig. 10B is another example of the present invention. Fig. 10A is a plan view of a gas flow path forming member, Fig. 10B yes Fig. 10A XX cross-section diagram.

[0052] Fig.11 This is a cross-sectional view showing an example of the prior art.

[0053] [Explanation of Symbols]

[0054] A: Pre-mixing device

[0055] B: Combustion device

[0056] Sa: Inner area (divided flow path)

[0057] Sb: Outer area (divided flow path)

[0058] 1: Fan

[0059] 2: Burner

[0060] 3a: First gas flow path (gas flow path)

[0061] 3b: Second gas flow path

[0062] 30a: Split flow path

[0063] 30a': First region (inner peripheral surface of divided flow path)

[0064] 4: Gas flow path forming member

[0065] 40: Partition wall

[0066] 41a, 41b: first blade portion and second blade portion

[0067] 45a~45c:Baffle part

[0068] 45a', 45b': Front edge (of the baffle)

[0069] 450: Air bearing surface

[0070] 5: Partition

[0071] 80a: First fuel gas outlet (fuel gas outlet)

[0072] 80b: Second fuel gas outlet DETAILED DESCRIPTION

[0073] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0074] For ease of understanding, Fig.11 The same or similar components as shown in the prior art are marked with Fig.11 Same symbols.

[0075] Figure 1 1 represents a hot water device WH. The hot water device WH is a hot water supply device, and includes a premixing device A, a combustion device B (premixing combustion device), and a heat exchanger 11. The combustion device B is composed of a fan 1 and a burner unit 2 combined with the premixing device A. The fan 1 has a variable speed (variable air volume).

[0076] The details of the premixing device A will be described later. The premixing device A is used to generate a mixed gas (combustible mixed gas) of air and fuel gas, and the mixed gas is supplied to the burner unit 2 via the fan 1. The burner unit 2 includes a porous plate 21 having a plurality of vents 20 (flame holes) and is arranged in the housing 10. The burner unit 2 is provided with an ignition spark plug or a flame detection sensor, etc., which are not shown in the figure. The mixed gas passes through the plurality of vents 20 and burns below the porous plate 21. The combustion gas generated by the burner unit 2 is heat-recovered by the heat exchanger 11. The heat exchanger 11 includes, for example, a primary heat exchanger 11a for sensible heat recovery and a secondary heat exchanger 11b for latent heat recovery. The combustion gas acts on these primary heat exchangers 11a and secondary heat exchangers 11b in sequence to heat the hot water passing through them. The warm water generated by the hot water heating is supplied to the desired hot water supply destination.

[0077] like Figure 2 to Figure 7 As shown, the premixing device A includes: a device body A0 and a partition plate 5 assembled in the device body A0.

[0078] The device body A0 includes a gas flow path forming member 4. The gas flow path forming member 4 includes: a cylindrical portion 49, in which the first gas flow path 3a and the second gas flow path 3b described later are formed; a flange portion 48, which is continuously provided at the upper end of the cylindrical portion 49; and a stepped pedestal portion 44, which is protrudingly provided on the outer surface of the cylindrical portion 49. The pipe body joint portion 70 for receiving the fuel gas and the fuel gas control plate 71 described later are installed on the pedestal portion 44 via screw members 90 and screw members 91 such as screws.

[0079] like Figure 1 As shown, the tube joint portion 70 of the premixing device A is connected to the gas pipe 99, and receives the supply of fuel gas from a fuel gas supply source not shown in the figure via an equalizing valve (zero pressure valve (zero governor)) V1. On the other hand, the premixing device A is directly or indirectly connected to the intake side of the fan 1 by means of the flange portion 48. If the fan 1 is driven, the external air flows into the gas flow path forming member 4 (inside the cylindrical portion 49). Due to the negative pressure generated by the flow of the air, the fuel gas flows out from the first fuel gas outlet 80a and the second fuel gas outlet 80b described later, generating a mixed gas of the fuel gas and the air. The mixed gas is supplied to the burner portion 2 via the fan 1.

[0080] like Figure 2 , Figure 3 , Figure 7As shown in detail, a partition wall portion 40 is provided in the cylindrical portion 49 of the gas flow path forming member 4, which is erected in the vertical height direction (the air flow direction in this embodiment) and extends in the x direction intersecting the air flow direction. Thus, a first gas flow path 3a and a second gas flow path 3b are formed in the cylindrical portion 49, which are arranged in the horizontal direction with the partition wall portion 40 interposed therebetween.

[0081] The first gas flow path 3a of the first gas flow path 3a and the second gas flow path 3b corresponds to an example of the "gas flow path" in the claims.

[0082] The partition wall portion 40 is arranged offset from the center of the cylindrical portion 49 in the y direction (a direction intersecting the x direction and the air flow direction), and the flow path area of ​​the first gas flow path 3a is smaller than the flow path area of ​​the second gas flow path 3b. However, the first gas flow path 3a and the second gas flow path 3b may also be set to the same flow path area.

[0083] like Figure 4A to Figure 6 As shown in detail, a first blade portion 41a and a second blade portion 41b (with Figure 5A In addition, the upper surface of the plurality of fuel gas outlets 80a and 80b are provided to open upward.

[0084] Here, the first blade portion 41 a of the first blade portion 41 a and the second blade portion 41 b corresponds to an example of the “blade portion” in the claims.

[0085] In addition, of the first fuel gas outflow port 80a and the second fuel gas outflow port 80b, the first fuel gas outflow port 80a corresponds to an example of the "fuel gas outflow port" in the claims.

[0086] The first blade portion 41a and the second blade portion 41b extend along the y direction in a manner that crosses the first gas flow path 3a and the second gas flow path 3b in the horizontal direction, respectively, and one end portion of each is connected to the inner surface portion of the peripheral wall of the gas flow path 3 (the inner surface portion of the peripheral wall portion of the cylindrical portion 49), and the other end portions of each are connected to each other via the partition wall portion 40.

[0087] exist Figure 4A , Figure 4CIn the figure, the tube body joint portion 70 has a fuel gas receiving portion 81 inside for receiving the supply of fuel gas from the outside. The fuel gas supplied to the fuel gas receiving portion 81 is guided to the first fuel gas flow outlet 80a and the second fuel gas flow outlet 80b via the opening portion 71a, the opening portion 71b and the first fuel gas flow path 8a and the second fuel gas flow path 8b of the fuel gas control plate 71.

[0088] As described above, the fuel gas control plate 71 is mounted on the base portion 44 and has two openings 71a and 71b facing the front end openings of the first fuel gas flow path 8a and the second fuel gas flow path 8b. Depending on the opening areas of these openings 71a and 71b, the amount of fuel gas flowing from the fuel gas receiving portion 81 to the first fuel gas flow path 8a and the second fuel gas flow path 8b can be controlled.

[0089] An air inlet 3c and an air outlet 3d connected to the first gas flow path 3a and the second gas flow path 3b are formed at the lower and upper parts of the cylindrical portion 49. If the fan 1 is driven, the external air can flow into the air inlet 3c and then branch and flow into the first gas flow path 3a and the second gas flow path 3b. As described above, due to the negative pressure generated by the flow of air in the first gas flow path 3a and the second gas flow path 3b, the fuel gas flows out from the first fuel gas outlet 80a and the second fuel gas outlet 80b to generate a mixed gas of air and fuel gas. The mixed gas flows out from the air outlet 3d to the outside of the cylindrical portion 49.

[0090] like Figure 6 As shown in detail, the first blade portion 41a divides a portion of the first gas flow path 3a into a pair of divided flow paths 30a, and the pair of divided flow paths 30a are arranged on both sides of the first blade portion 41a in the x direction.

[0091] The pair of divided flow paths 30a is equivalent to an example of "a pair of divided flow paths" in the claims. As an additional structure in the pair of divided flow paths 30a, in this embodiment, the baffle portion 45a and the baffle portion 45b are included, and the structure has a major feature. The details will be described later.

[0092] A portion of the second gas flow path 3b is divided into a pair of divided flow paths 30b sandwiching the second blade portion 41b, but the pair of divided flow paths 30b does not correspond to the "pair of divided flow paths" in the claims. In this embodiment, the structure using the baffle portions 45a and 45b is only applicable to the first gas flow path 3a side of the first gas flow path 3a and the second gas flow path 3b.

[0093] When the total air flow rate of the first gas flow path 3a and the second gas flow path 3b is small, the partition 5 moves in accordance with the total air flow rate in such a way that the opening becomes smaller than the opening when the total air flow rate is large, and the objects of its opening and closing control are the second gas flow path 3b and the second fuel gas flow outlet 80b. To be more specific, a shaft body 61 serving as a rotation fulcrum is inserted through the rear part of the partition 5, and the shaft body 61 is supported by a pair of left and right support members 60. In addition, the pair of support members 60 are mounted on a step portion 43 additionally provided in the second gas flow path 3b using threaded members 92 or the like. Thus, the partition 5 can rotate on the upper side of the second blade portion 41b according to the total air flow rate with the shaft body 61 as the center. When the total air flow rate is less than the specified value, as Figure 4A As shown in FIG. 1 , the separator 5 is in a closed state due to its own weight, blocking the second gas flow path 3b and the second fuel gas flow outlet 80b. On the other hand, when the total air flow rate is greater than a predetermined value, for example, Figure 4C As shown, the separator 5 is pushed up by the air flow, and the second gas flow path 3b and the second fuel gas outlet 8b are in an open state.

[0094] In addition, in the present embodiment, the partition plate 5 includes a pair of fin portions 55 (see FIG. 1 ) which are arranged close to both sides of the second blade portion 41 b via the gap 97. Figure 4B ). However, the present invention is not limited thereto.

[0095] like Figure 5A to Figure 7 As shown in detail, two baffle portions 45a, 45b (in the inner peripheral surface of each divided flow path 30a of the first gas flow path 3a) are provided. Figure 5C (with light ink in it).

[0096] The baffle portion 45a and the baffle portion 45b are the following parts, that is, they are used to speed up the flow rate of the air flowing in the outer area Sb on the opposite side relative to the flow rate of the air flowing in the inner area Sa on the side of the first blade portion 41a in each divided flow path 30a (the details of their specific functions and effects will be described later).

[0097] The baffles 45a and 45b are located on the inner circumferential surface of each segmented flow path 30a, further upstream in the air flow direction than the first fuel gas outlet 80a, and are in the form of a protruding sheet or a stepped portion that protrudes toward the inner side of each segmented flow path 30a. Figure 6 and Figure 7 As shown, the baffle portions 45a and 45b have air receiving surfaces 450 facing downward (upstream in the air flow direction) and projecting in a substantially horizontal direction from a general portion of the inner circumferential surface of each divided flow path 30a.

[0098] exist Figure 5B, Figure 5C When viewed in a plane or in a top cross-section (viewed in the direction of air flow), the baffle portions 45a and 45b are arranged to be separated from each other and face each other in the y direction, and at least a portion of these baffle portions 45a and 45b is located in the inner area Sa of each segmented flow path 30a. The baffle portions 45a and 45b are arranged to avoid the portion close to the center in the length direction (y direction) of the first blade portion 41a. More specifically, the inner peripheral surface of each segmented flow path 30a includes a pair of first areas 30a' adjacent to the first blade portion 41a and separated and facing each other in the y direction. In contrast, the baffle portions 45a and 45b are respectively arranged in a pair of first areas 30a'. In addition, the front edges 45a' and 45b' of these baffle portions 45a and 45b are inclined in a manner that the closer they are to the first blade portion 41a in the x direction, the closer they are to the y-direction center of each segmented flow path 30a.

[0099] The baffle portions 45a and 45b are arranged to avoid at least a portion of the outer region Sb of each divided flow path 30a (in the outer region Sb, there is a portion where the baffle portions 45a and 45b are not provided).

[0100] Next, the operation of the premixing device A and the combustion device B including the premixing device A will be described.

[0101] When the drive combustion of the burner section 2 of the combustion device B starts, or in the normal drive combustion thereafter, the drive speed of the fan 1 is changed to change the flow rate of the mixed gas supplied from the premixing device A to the burner section 2, thereby controlling the drive combustion firepower of the burner section 2.

[0102] Here, when the driving speed of the fan 1 is low and the air flow rate in the gas flow path forming member 4 is small, as shown in FIG. Figure 4A As shown in FIG. 1 , the partition plate 5 is in a closed state, and air does not flow in the second gas flow path 3b, but only flows in the first gas flow path 3a. In the above case, if the air flow in the first gas flow path 3a becomes quite small, the negative pressure caused by the flow of air will not strongly act on the first fuel gas outlet 80a. On the other hand, the phenomenon that the air of the pair of divided flow paths 30a that respectively pass through the first gas flow path 3a merges at the positions near the first fuel gas outlet 80a in a relatively large proportion is similar to the phenomenon described in FIG. Fig.11 In the same manner as in the conventional art described above, the outflow rate of the fuel gas from the first fuel gas outlet 80a is further reduced. In contrast, according to the present embodiment, such a disadvantage can be appropriately suppressed as described below.

[0103] That is, due to the action of the baffle portions 45a and 45b, the flow velocity of air passing through the outer region Sb of each divided flow path 30a is faster than the flow velocity of air passing through the inner region Sa.

[0104] To illustrate this point, Figure 8B In the comparative example, the baffles 45a and 45b are not provided on the inner peripheral surface of the divided flow path 30a. In the above case, the air simply flows along the inner peripheral surface of the divided flow path 30a. In contrast, in the present embodiment, Fig. 8A As shown, a part of the air flowing along the inner peripheral surface of the divided flow path 30a collides with the baffle portion 45a (45b), and a vortex is generated in the upstream area of ​​the baffle portion 45a (45b) in the air flow direction. The baffle portion 45a (45b) has an air receiving surface 450 facing the upstream side in the air flow direction, which is advantageous in reliably generating the vortex.

[0105] When the eddy current is generated, the following effects can be obtained.

[0106] First, the vortex itself does not directly move to the downstream side. In addition, the flow velocity of the air flowing near the vortex is affected by the vortex, and its flow velocity is easily reduced. On the other hand, the baffle parts 45a and 45b are arranged in the inner area Sa of each divided flow path 30a, and the vortex is generated in the said area. Therefore, the flow velocity of the air passing through the inner area Sa becomes slower, and the flow velocity of the air passing through the outer area Sb becomes relatively faster.

[0107] Second, if Fig. 8A As shown in FIG. 1 , the air moving toward the baffle portion 45a (45b) from the upstream side thereof mostly moves in a manner of expanding toward the side of the vortex, and its moving direction changes so as to move closer to the inside of the divided flow path 30a than the original moving direction. On the other hand, the front edges 45a' and 45b' of the baffle portions 45a and 45b are as shown in FIG. Figure 5B , Figure 5C Therefore, the air passing through the front edge 45a' and the front edge 45b' of the baffle portion 45a and the baffle portion 45b flows toward the side opposite to the first blade portion 41a as shown by the arrows Na and Nb. Therefore, the air flow rate of the outer area Sb of each divided flow path 30a increases, and the flow speed of the air in the outer area Sb becomes faster.

[0108] Furthermore, unlike the present embodiment, if a portion of the baffle portions 45a and 45b is extended to the outer region Sb, there is a concern that the portion of the baffle portions 45a and 45b may function to cause the air traveling in the outer region Sb to flow toward the inner region Sa. In the present embodiment, such a concern can also be appropriately avoided.

[0109] As described above, if the flow rate of the air near the outer area Sb is increased, the air flowing in the pair of split flow paths 30a is suppressed from merging at the opposite positions near the first fuel gas outlet 80a. The merging of the air hinders the outflow of the fuel gas from the first fuel gas outlet 80a to the first gas flow path 3a, but the merging is appropriately suppressed. As a result, according to the present embodiment, compared with the case where the baffle portion 45a and the baffle portion 45b are not provided, the negative pressure of the air flow acting on the first fuel gas outlet 80a may be slightly reduced, but overall, the outflow of the fuel gas from the first fuel gas outlet 80a can be increased. Therefore, even in the case of a small air flow rate, an appropriate amount of fuel gas and air that matches the air flow rate can be mixed, and a mixed gas with an appropriate mixing ratio can be obtained, thereby improving the adjustment ratio.

[0110] On the other hand, in this embodiment, although the baffles 45a and 45b are provided on the inner circumference of each segmented flow path 30a, the baffles 45a and 45b are in the shape of a protruding piece or a stepped portion, and the inner diameter of the length dimension area of ​​each segmented flow path 30a is not formed into a small diameter. In addition, the length of the baffles 45a and 45b is not provided across the entire circumference of the inner circumference, and is not provided on the inner circumference of the outer area Sb, etc., but is provided locally. Therefore, the flow resistance of each segmented flow path 30a will not increase significantly. Therefore, the pressure loss of air flow can also be reduced.

[0111] Different from the above, if the driving speed of the fan 1 is high and the air flow rate in the gas flow path forming member 4 is greater than a predetermined value, then Figure 4C As shown, the partition 5 is in an open state, and the air also flows to the second gas flow path 3b. Here, the second gas flow path 3b is not provided with components equivalent to the baffle portion 45a and the baffle portion 45b. The so-called situation where the air flows to the second gas flow path 3 refers to the situation where the air flow rate is large. The negative pressure generated by the air flow can strongly act on the second fuel gas outlet 80b, so there is no worry about insufficient outflow of fuel gas, or almost no worry. Therefore, although the second gas flow path 3b is not provided with components equivalent to the baffle portion 45a and the baffle portion 45b, no particular adverse situation will occur.

[0112] FIG. 9A to FIG. 9B as well as Figure 10A to Figure 10BIn these drawings, the same or similar elements as those in the above-described embodiment are denoted by the same reference numerals as those in the above-described embodiment, and repeated description is omitted.

[0113] exist FIG. 9A to FIG. 9B In the embodiment shown in the figure, a pair of baffle portions 45c ( Fig. 9A The two side surface portions correspond to a portion of the inner peripheral surface of the first gas flow path 3a.

[0114] According to the present embodiment, the air traveling toward the baffle portion 45c changes direction in the direction away from the first blade portion 41a in the x direction as indicated by the arrow Nc. Therefore, it is possible to suppress the air passing through a pair of split flow paths 30a from merging at the opposing positions near the first fuel gas outlet 80a. Thus, the fuel gas outflow from the first fuel gas outlet 80a can be properly performed. In addition, if the width Lc of the baffle portion 45c is too large, the part where the air flows is too far from the first fuel gas outlet 80a, and the negative pressure cannot be effectively applied to the first fuel gas outlet 80a, but by setting the width Lc to an appropriate value, this situation can be properly avoided.

[0115] exist Figure 10A to Figure 10B In the embodiment shown, as the first fuel gas outlet, a pair of first fuel gas outlets 80a are provided in a transverse opening shape in the area near the upper end (the area near one end downstream of the air flow direction) of the first blade portion 41a on both sides. The pair of first fuel gas outlets 80a face each other with the downstream area of ​​the air flow direction of the pair of divided flow paths 30a. In addition, a gas flow path blocking wall portion 41c is provided on the upper side between the pair of first fuel gas outlets 80a to prevent the gas of the first fuel gas flow path 8a from flowing out from a different part from the pair of first fuel gas outlets 80a in the transverse opening shape.

[0116] According to the present embodiment, before the air flowing through the pair of divided flow paths 30a branches off and flows toward the downstream side of the air flow direction of the first blade portion 41a and merges with each other, the negative pressure generated by the flow of the air can be applied to the pair of first fuel gas outlets 80a. Therefore, when the air flow rate of the first gas flow path 3a is small, the outflow of the fuel gas can be more reliably prevented from being too small.

[0117] The present invention is not limited to the contents of the above-described embodiment. The specific structures of the premixing device and the combustion device of the present invention can be freely modified in various designs within the intended scope of the present invention.

[0118] The gas flow path (the first gas flow path in the embodiment) in the present invention is preferably a Venturi-shaped one, but is not limited thereto. In addition, the gas flow path forming member may not necessarily have the first gas flow path and the second gas flow path, and may have only one gas flow path, for example.

[0119] Furthermore, when the first gas flow path and the second gas flow path are provided as in the above embodiment, and a partition is provided in the second gas flow path, a partition that is opened and closed by a motor may be used as the partition.

[0120] The fuel gas is, for example, natural gas or liquefied petroleum gas, but is not limited to a specific type. The combustion device of the present invention is not limited to the use of a warm water device, and can also be set as a combustion device for other purposes such as heating or incineration. In addition, it is not limited to a type that allows the combustion gas to move downward, and can also be set as a type that allows the combustion gas to move upward, for example.

Claims

1. A premixing device comprising: a gas flow path forming member having a gas flow path formed therein for allowing air supplied from the outside to flow; a blade portion disposed in the middle of the gas flow path, and having a fuel gas outflow port in a region close to one end on the downstream side of the air flow direction, the fuel gas outflow port being capable of using a negative pressure generated by the flow of the air to allow the fuel gas to flow into the gas flow path; and a pair of divided flow paths, wherein a portion of the gas flow path is divided by the blade portion, and the blade portion is sandwiched between the two sides thereof in an x ​​direction intersecting the air flow direction, The premixing device is characterized in that it further comprises a baffle portion in the shape of a tab or a step, The protruding piece or stepped baffle portion is located on the inner peripheral surface of each of the divided flow paths, upstream of the fuel gas outflow port in the air flow direction, and protrudes toward the inner direction of each of the divided flow paths. The baffle portion is arranged on at least a portion of the inner region on the blade portion side in each of the divided flow paths, and is configured to make the flow rate of air flowing in the outer region on the opposite side of the inner region in each of the divided flow paths faster than the flow rate of air passing through the inner region.

2. The premixing device according to claim 1, wherein: The baffle portion is provided so as to avoid at least a portion of the outer region in each of the divided flow paths.

3. The premixing device according to claim 1, wherein: The baffle portion has an air receiving surface facing the upstream side in the air flow direction, The air is configured to collide with the air receiving surface to generate a vortex of the air, and the air moves toward the air receiving surface from a position on the upstream side in the air flow direction along the inner peripheral surface of each of the divided flow paths.

4. The premixing device according to claim 3, wherein: When observing the air flow direction in the gas flow path, the inner peripheral surface of each of the divided flow paths includes a pair of first regions, the pair of first regions are adjacent to the blade portion and are separated and face each other in the y direction intersecting the x direction, The baffle portion includes a baffle portion provided in at least one of the pair of first regions, wherein a front end edge of the baffle portion is inclined so as to be closer to a center of each of the divided flow paths in the y direction as it approaches the blade portion in the x direction.

5. The premixing device according to claim 1, wherein: The fuel gas outflow outlet includes a pair of fuel gas outflow outlets, which are opened on both side surfaces of the blade portion near the one end and face each other with the downstream side areas of the pair of divided flow paths in the air flow direction.

6. The premixing device according to claim 1, wherein: The gas flow path and the fuel gas outflow port are respectively a first gas flow path and a first fuel gas outflow port, The premixing device also includes: a second gas flow path provided in the gas flow path forming member in a state of being separated from the first gas flow path via a partition wall portion; an air inlet portion provided in the gas flow path forming member so as to allow air supplied from the outside to be branched and to flow to the first gas flow path and the second gas flow path respectively; a second fuel gas outflow port capable of causing the fuel gas to flow toward the second gas flow path by utilizing a negative pressure generated by the flow of the air in the second gas flow path; and The partition can close the second gas flow path when the total air flow rate of the first gas flow path and the second gas flow path is less than a predetermined value, so that the air flows only in the first gas flow path of the first gas flow path and the second gas flow path.

7. A combustion device, comprising: a premixing device for generating a mixed gas of air and fuel gas; and A burner unit receives the mixed gas from the premixing device and burns the fuel gas, wherein the combustion device is characterized in that: As the premixing device, the premixing device according to any one of claims 1 to 6 is used.

8. A premixing device comprising: a gas flow path forming member having a gas flow path formed therein for allowing air supplied from the outside to flow; a blade portion disposed in the middle of the gas flow path, and having a fuel gas outflow port in a region close to one end on the downstream side of the air flow direction, the fuel gas outflow port being capable of using a negative pressure generated by the flow of the air to allow the fuel gas to flow into the gas flow path; and A pair of divided flow paths, wherein a portion of the gas flow path is divided by the blade portion, and the blade portion is sandwiched and arranged on both sides thereof in an x ​​direction intersecting the air flow direction, wherein the premixing device The fuel gas outflow outlet includes a pair of fuel gas outflow outlets, which are opened on both side surfaces of the blade portion near the one end and face each other with the downstream side areas of the pair of divided flow paths in the air flow direction.

9. A combustion device, comprising: a premixing device for generating a mixed gas of air and fuel gas; and A burner unit receives the mixed gas from the premixing device and burns the fuel gas, wherein the combustion device is characterized in that: As the premixing device, the premixing device according to claim 8 is used.

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