Premixing device and combustion apparatus including the same

Abstract

To provide a premixing device capable of easily, promptly and appropriately responding to a type of fuel gas and a combustion apparatus including the premixing device.SOLUTION: In a premixing device A, a first wall surface part S1 on which part of fuel gas flow passages 8a, 8b is opened is provided in a base part 44 of a premixing flow passage formation member 4 as a portion to oppose to a flow passage adjustment member 2. The flow passage adjustment member 2 includes a claw part 23 capable of holding a seal member 7 on a second wall surface part S2 on a rear surface side of the flow passage adjustment member 2. A pipe joint part 9 can be mounted to the base part 44 while sandwiching the flow passage adjustment member 2 so that the seal member 7 is nipped between the first and second wall surface parts S1, S2.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a premixing device and a combustion device equipped with the same. Here, "premixing" refers to a process of mixing air and fuel gas in advance to generate a combustible mixed gas for the purpose of performing premixing combustion. [Background technology]

[0002] A specific example of a premixing device is described in Patent Document 1. The premixing device described in the document includes a premixing channel-forming member that forms a premixing channel for allowing air to flow from one end to the other and for mixing fuel gas with the air. The premixing channel-forming member is provided with a base to which a pipe fitting for connecting a gas pipe is attached. Fuel gas supplied from the gas pipe to the pipe fitting passes through a predetermined fuel gas channel, reaches a fuel gas outlet at the end of the channel, and flows into the premixing channel. As a result, a mixture of fuel gas and air is generated in the premixing channel, and this mixture is supplied downstream of the premixing device.

[0003] There are two types of fuel gas, for example, natural gas and LPG, which have different components and heating values, so the premixing device must be designed to accommodate the type of fuel gas.In other words, when the negative pressure generated in the premixing channel is the same, the amount of fuel gas with a lower heating value that flows out from the fuel gas outlet into the premixing channel must be set to be greater than the amount of fuel gas with a higher heating value.

[0004] Therefore, in Patent Document 1, a predetermined flow path adjusting member is attached directly or indirectly to the premixing flow path forming member, and the flow path resistance of the fuel gas flow path can be changed by changing the attachment mode, making it possible to set it to one suitable for the type of fuel gas. With this configuration, it is possible to appropriately handle multiple types of fuel gas.

[0005] However, the above-mentioned prior art still has room for improvement, as will be described below.

[0006] That is, it is desirable to make it possible to change the flow path adjusting member according to the type of fuel gas as easily and quickly as possible. This is even more desirable because the change may be performed on-site at the installation site of the water heater equipped with the premixing device. Therefore, it is desirable to improve the ease of the change to accommodate the type of fuel gas compared to Patent Document 1. Naturally, care must also be taken to ensure appropriate sealing and to prevent unwanted fuel gas leakage. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 7385804 [Patent Document 2] Patent No. 5373671 [Patent Document 3] Patent No. 2857352 [Patent Document 4] Japanese Utility Model Application Publication No. 52-159434 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention was conceived under the circumstances described above, and provides a premixing device that can easily, quickly, and appropriately accommodate different types of fuel gas, and a combustion device equipped with the same. The goal is to provide a place where [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides the following technical solutions.

[0010] A premixing device provided by a first aspect of the present invention comprises a premixing flow path forming member that forms a premixing flow path for flowing air from one end side to the other end side and mixing a fuel gas with the air, a base portion that is provided on the premixing flow path forming member and for attaching a pipe joint portion to which a gas pipe for supplying the fuel gas is connected, a fuel gas flow path whose terminal end is formed as a fuel gas outlet port for discharging the fuel gas into the premixing flow path and for guiding the fuel gas supplied to the pipe joint portion to the fuel gas outlet, and an opening that forms part of the fuel gas flow path, and the opening is configured to be adapted to accommodate a type of fuel gas. A premixing device includes a flow path adjustment member set to a corresponding opening area, and a sealing member for sealing an attachment location of the flow path adjustment member, wherein the base portion is provided with a first wall surface portion, which has an opening in part of the fuel gas flow path, as a portion for facing the flow path adjustment member, the flow path adjustment member has claw portions that can hold the sealing member on a second wall surface portion on the rear side of the flow path adjustment member, and the pipe joint portion can be attached to the base portion in a state where the flow path adjustment member is sandwiched so that the sealing member is sandwiched and pressed between the first and second wall surface portions.

[0011] According to this configuration, by using a flow path adjusting member having an opening with an opening area corresponding to the type of fuel gas, it is possible to adjust the flow path resistance of the fuel gas flow path to suit the type of fuel gas. In addition to the above, the following effects can be obtained. That is, when the flow path adjusting member is attached, the seal member is sandwiched between a predetermined first wall surface portion of the base portion and a second wall surface portion on the rear side of the flow path adjusting member, providing excellent sealing performance in this portion, thereby ensuring high reliability in preventing fuel gas leakage. The sealing member can be held by utilizing the claws of the flow path adjustment member, so the sealing member and the flow path adjustment member can be handled together, making it easier to attach and remove them to and from the premixing flow path forming member. The flow path adjustment member can be attached to the premixing flow path forming member by sandwiching the flow path adjustment member between the pipe joint portion and the base portion of the premixing flow path forming member when the pipe joint portion is attached to the base portion of the premixing flow path forming member. This makes it easier to attach the flow path adjustment member and also to remove it.

[0012] In the present invention, preferably, the flow path adjustment member comprises a main body member having a cylindrical wall portion whose inner region constitutes part of the fuel gas flow path and from which the claw portion protrudes at one end side of the cylindrical wall portion, and an auxiliary member superimposed on the one end side of the cylindrical wall portion and having the opening, the second wall surface portion, and a hole portion or a notch portion through which the claw portion is inserted, and the sealing member is superimposed on the second wall surface portion of the auxiliary member so that the auxiliary member is sandwiched between the main body member and the sealing member, and engages with an engaging portion provided on the tip side of the claw portion.

[0013] This configuration provides the following effects. That is, by assembling the auxiliary member and the seal member in a state where they are overlapped on the main body member of the flow path adjusting member, they can be handled as a whole, and the workability of installation and removal can be improved. Here, if, for example, only one of the auxiliary member and the seal member is overlapped on the main body member and the other is not overlapped, resulting in an improper combination, one of the auxiliary member and the seal member will not be fixed to the main body member. Therefore, the worker attempting to install the flow path adjusting member and the seal member can easily notice this, and For example, the risk of attaching the flow path adjusting member to the base portion with the sealing member missing can be appropriately eliminated.

[0014] In the present invention, preferably, the flow path adjustment member has a cylindrical wall portion whose inner region forms part of the fuel gas flow path, and the second wall surface portion in which the opening is provided and the claw portion are integrally molded with this cylindrical wall portion.

[0015] With this configuration, the number of parts in the flow path adjustment member can be reduced compared to a flow path adjustment member that is composed of two members, for example, a main member and an auxiliary member, making it easier to handle and also reducing manufacturing costs.

[0016] In the present invention, preferably, the base portion is provided with a first recess having a front opening, and the flow path adjustment member can be set in a state in which its rear portion is fitted into this first recess, and when the pipe fitting portion is removed from the base portion, the front portion of the flow path adjustment member is configured to protrude outward and forward from the base portion.

[0017] With this configuration, when attaching the flow path adjustment member to the base portion, the rear portion of the flow path adjustment member can be inserted into and supported by the first recess. Therefore, in this state, the pipe fitting portion can be attached to the base portion, further facilitating the attachment work of the flow path adjustment member and the pipe fitting portion. Furthermore, when the pipe fitting portion is removed from the base portion while the flow path adjustment member and the pipe fitting portion are attached to the base portion, the front portion of the flow path adjustment member protrudes outward and forward from the base portion. Therefore, by grasping this protruding portion, the entire flow path adjustment member can be easily pulled out of the first recess.

[0018] In the present invention, preferably, the first wall surface portion of the base portion is provided with a second recess into which the claw portion can enter.

[0019] With this configuration, when the flow path adjustment member is attached, it is possible to avoid undue interference between the claw portion and the first wall surface portion of the base, and it is easy to ensure that the claw portion does not interfere with the abutment of the sealing member against the first wall surface portion. Furthermore, as will be described later with reference to Fig. 13, when the sealing member is attached to the first wall surface portion, the second recess can also be used as a recess for inserting a tool to peel off the sealing member.

[0020] In the present invention, preferably, the fuel gas supply system further includes a partition wall portion that divides the premixing flow path into first and second flow paths arranged in parallel, the fuel gas flow path branches into first and second fuel gas flow paths, and the first and second fuel gas flow paths have, as the fuel gas outlets, first and second fuel gas outlets that are provided to allow fuel gas to flow into the first and second flow paths, and the openings of the flow path adjustment member include first and second openings that correspond to the first and second fuel gas flow paths.

[0021] With this configuration, both the first and second fuel gas flow paths for supplying fuel gas to the first and second flow paths of the premixing flow path can be configured to appropriately correspond to the type of fuel gas.

[0022] In the present invention, preferably, the flow path adjustment member has a cylindrical wall portion whose inner region constitutes a part of the fuel gas flow path, and the opening of the flow path adjustment member is provided with a third opening portion located upstream of the first and second opening portions in the fuel gas flow direction, and the fuel gas passing through this third opening portion is configured to proceed to the first and second opening portions. It is being done.

[0023] With this configuration, the flow path resistance of each of the first and second flow paths can be controlled using not only the first and second openings of the flow path adjustment member, but also the third opening, thereby making it possible to improve the control accuracy.

[0024] A combustion device provided according to a second aspect of the present invention is characterized by comprising the premixing device provided according to the first aspect of the present invention.

[0025] Other features and advantages of the present invention will become more apparent from the following description of the preferred embodiments of the invention, which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0026] [Figure 1]1 is a schematic explanatory diagram showing an example of a combustion apparatus equipped with a premixing device according to the present invention. [Figure 2] FIG. 2 is a perspective view of the appearance of the premixing device of FIG. 1. [Figure 3] FIG. 3 is an exploded perspective view of FIG. 2. [Figure 4] 3(a) is a front cross-sectional view of the premixing device shown in FIG. 2, and FIG. 3(b) is an exploded cross-sectional view thereof. [Figure 5] 3(a) is a plan cross-sectional view of the main part of the premixing device shown in FIG. 2, and FIG. 3(b) is an exploded cross-sectional view thereof. [Figure 6] 4(a) is a cross-sectional view of the premixing device shown in FIG. 2 at a different location from that shown in FIG. 4(a), and FIG. 4(b) is a cross-sectional view taken along line VIb-VIb of FIG. 4(a). [Figure 7] 3(a) is a plan view of a premixing flow path forming member of the premixing device shown in FIG. 2, (b) is an enlarged view of a main part thereof, and (c) is a plan cross-sectional view of (a). [Figure 8] 3(a) is a perspective view showing an assembly of a flow path adjusting member and a sealing member of the premixing device shown in FIG. 2, and FIG. 3(b) is an exploded perspective view of FIG. [Figure 9] 8(a) is a perspective view of the assembly shown in FIG. 8(a) from a different direction, and (b) is an exploded perspective view of (a). [Figure 10] 8 and 9, and (b) is an exploded cross-sectional view of (a). [Figure 11] 8 and 9, and (b) is an exploded cross-sectional view of (a). [Figure 12] FIG. 4(a) is a schematic front view showing the base portion and the pipe joint portion of the premixing flow path forming member shown in FIGS. 2 and 3, and FIGS. 4(b) and 4(c) are schematic front views showing the state in which the pipe joint portion is attached to the base portion. [Figure 13] 4 is a cross-sectional view of a main part showing an example of a countermeasure when a seal member is stuck to a base portion of the premixing flow path forming member shown in FIGS. 2 and 3. FIG. [Figure 14]10(a) is a plan cross-sectional view showing another example of an assembly of a flow path adjusting member and a sealing member of a premixing device, and FIG. 10(b) is a vertical cross-sectional view of FIG. [Figure 15] FIG. 10 is an exploded perspective view showing another example of a flow path adjusting member and a sealing member of the premixing device. DETAILED DESCRIPTION OF THE INVENTION

[0027] Preferred embodiments of the present invention will now be described in detail with reference to the drawings.

[0028] Fig. 1 shows a hot water device WH. This hot water device WH is a water heating device and includes a premixing device A, a combustion device B (premix combustion device), and a heat exchanger 11. The combustion device B is configured by combining the premixing device A with a fan 1 and a burner unit 12. The fan 1 has a variable speed (variable airflow rate).

[0029] Details of the premixing device A will be described later. A mixture of air and fuel gas (a combustible mixture) is generated using this premixing device A, and this mixture is supplied to the burner unit 12 via the fan 1. The burner unit 12 is equipped with a perforated plate 12a having a plurality of vent holes 12b (flame holes) and is housed in a case 10. The burner unit 12 is equipped with an ignition plug, a flame detection sensor, and other components (not shown). The mixture passes through the plurality of vent holes 12b and is combusted below the perforated plate 12a. The combustion gas generated by the burner unit 12 acts on the heat exchanger 11, and the hot water passing through this heat exchanger 11 is heated. This generates hot water, which is then supplied to a desired hot water supply destination.

[0030] As clearly shown in FIGS. 2 to 6, the premixing device A includes a device main body A0, and a flapper 5, a flow path adjusting member 2, and a sealing member 7 that are assembled to the device main body A0. In the drawing, the x and y directions are directions that intersect with each other and also intersect with the air flow direction (upward) in the premixing channel 3, which will be described later.

[0031] The device main body A0 includes a premixing flow path forming member 4 and a pipe joint 9. The premixing flow path forming member 4 includes a cylindrical portion 49 that forms the venturi-shaped premixing flow path 3 therein, an attachment flange portion 48 connected to the upper end of the cylindrical portion 49, a base portion 44, and a fuel gas flow path 8.

[0032] The pipe joint 9 is connected to a gas pipe 99 (see FIG. 1) and receives a supply of fuel gas. The pipe joint 9 includes a cylindrical portion 94 that defines a hollow portion inside, which is the starting end of the fuel gas flow path 8, and an attachment flange 95 that is connected to the base end of the cylindrical portion 94.

[0033] The base portion 44 is the portion to which the pipe coupling portion 9 is attached, and is shaped like a pedestal or similar that is provided integrally with the outer peripheral surface portion of the cylindrical portion 49, and is provided with a flange portion 44a that corresponds to the flange portion 95 of the pipe coupling portion 9. The pipe coupling portion 9 is attached to the base portion 44 by fastening the flange portions 95, 44a together using threaded members 90 such as screws while the flange portions 95, 44a are in opposing contact with each other.

[0034] The flange portion 44a of the base portion 44 is provided with gas type indicators 98a, 98b that indicate the type of fuel gas supplied to the premixing device A. The gas type indicators 98a, 98b are, for example, the letters "NG" and "LP," respectively, the former indicating natural gas and the latter indicating LP gas. The flange portion 95 of the pipe joint portion 9 has a non-circular shape when viewed from the front, and can be set to selectively hide either one of the gas type display portions 98a, 98b and not hide the other, as will be described below. That is, the pipe fitting 9 and the base 44 are configured as shown in FIG. 12(a) when viewed from the front. When the pipe fitting 9 is attached to the base 44 in the orientation shown in the figure, the pipe fitting 9 hides the letters "LP" on the gas type display 98b, but does not hide the letters "NG" on the gas type display 98a, as shown in FIG. 12(b). This state can be set when the fuel gas is natural gas. In contrast, when the pipe fitting 9 is turned upside down, the pipe fitting 9 hides the letters "NG" on the gas type display 98a, but does not hide the letters "LP" on the gas type display 98b, as shown in FIG. 12(c). This state can be set when the fuel gas is LP gas.

[0035] As shown in Figure 1, the premixing device A has a pipe joint 9 connected to a gas pipe 99, and receives a supply of fuel gas from a fuel gas supply source (not shown) via a pressure equalizing 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 using a flange portion 48. When the fan 1 is driven, external air flows into the premixing flow path forming member 4 (the premixing flow path 3 in the cylindrical portion 49). The negative pressure generated by this air flow causes fuel gas to flow out from first and second fuel gas outlets 80a and 80b (described later), and a mixture of this fuel gas and the air is generated. This mixture is supplied to the burner portion 12 via the fan 1.

[0036] 6(a) and 7, a partition wall 40 extending in the vertical direction along the air flow direction is provided in the premixing channel 3. This divides a portion of the premixing channel 3 into first and second channels 3a and 3b that are aligned in the y direction with the partition wall 40 in between. 4 to 7, first and second blade portions 41a and 41b (shown as dotted portions in FIGS. 7(a) and 7(c)) are provided in the first and second flow paths 3a and 3b. First and second fuel gas outlet ports 80a and 80b are provided on the upper surfaces of the first and second blade portions 41a and 41b facing downstream in the air flow direction, and open upward.

[0037] The first and second blade portions 41a, 41b extend in the y direction so as to horizontally cross the first and second flow paths 3a, 3b, respectively, and one end of each of them is connected to the inner surface of the peripheral wall of the premixing flow path 3 (the inner surface of the peripheral wall of the cylindrical portion 49), and the other ends of each of them are connected to each other with the partition wall portion 40 in between. 7, a portion of the first flow path 3a is divided into a pair of regions 3a' that sandwich the first blade portion 41a in the x direction. A portion of the second flow path 3b is divided into a pair of regions 3b' that sandwich the second blade portion 41b in the x direction.

[0038] The fuel gas flow path 8 begins within the cylindrical portion 94 of the pipe joint 9 and terminates at first and second fuel gas outlets 80a, 80b. However, the downstream portion of the fuel gas flow path 8 branches into first and second fuel gas flow paths 8a, 8b at first and second openings 22a, 22b (described later) of the flow path adjusting member 2. The first and second fuel gas flow paths 8a, 8b are formed inside the base portion 44 and inside the first and second blade portions 41a, 41b. The fuel gas supplied to the pipe joint portion 9 passes through the first and second openings 22a, 22b of the flow path adjustment member 2 and the first and second fuel gas flow paths 8a, 8b, and is guided to the first and second fuel gas outlets 80a, 80b.

[0039] An air inlet 3c and an air outlet 3d, which communicate with the first and second flow paths 3a and 3b, are formed in the lower and upper parts of the cylindrical portion 49. When the fan 1 is driven, external air flows into the air inlet 3c and then branches off into the first and second flow paths 3a and 3b. Due to the negative pressure generated by the air flow in the first and second flow paths 3a and 3b, fuel gas flows out from the first and second fuel gas outlets 80a and 80b, generating a mixture of air and fuel gas. This mixture flows out of the cylindrical portion 49 through the air outlet 3d.

[0040] As shown in FIGS. 4 to 6, the flapper 5 can simultaneously open and close the first flow path 3a (the pair of regions 3a') and the first fuel gas outlet 80a. The flapper 5 is, for example, a resin molded product, and its base end is supported by a support portion 52 using a shaft 61, and is able to swing up and down in the height direction around the center line CL. As clearly shown in FIG. 3, the shaft 61 is supported by a pair of auxiliary members 60 each having a support hole 60a. The pair of auxiliary members 60 are attached to a step portion 43 separately provided in the first flow path 3a using a screw member 92 or the like.

[0041] The flapper 5 swings using its own weight as a downward force and the airflow traveling upward through the first flow path 3a as an upward force, and when the air flow rate in the premix flow path 3 is low, the opening degree is smaller than when it is high. When the air flow rate is low, the flapper 5 falls sideways due to its own weight and enters a closed state, but when the air flow rate increases, the flapper 5 is lifted by the upward air flow and enters an open state. A pair of fins 55 are appropriately provided on the flapper 5 so as to sandwich the first blade portion 41a when the flapper 5 is in the closed state.

[0042] The flow path adjustment member 2 is a member for controlling the flow path resistance of each of the first and second fuel gas flow paths 8a, 8b, and for controlling the fuel gas flow rate toward the first and second fuel gas outlets 80a, 80b to a flow rate corresponding to the type of fuel gas. As can be clearly seen in FIGS. 8 to 11, this flow path adjusting member 2 is a combination of a main body member 2a and an auxiliary member 2b.

[0043] The main body member 2a includes a cylindrical wall portion 20a whose inner region forms part of the fuel gas flow path 8, a third opening 22c provided in a front wall portion 20b of the cylindrical wall portion 20a, and a pair of claw portions 23 protruding from one end (toward the rear wall portion) of the cylindrical wall portion 20a. The tip of each claw portion 23 is hook-shaped or similar, and serves as an engaging portion 23a for holding the seal member 7.

[0044] The auxiliary member 2b includes short cylindrical portions 24a, 24b having first and second openings 22a, 22b, and a plate-like portion 25 to which the cylindrical portions 24a, 24b are connected. The rear surface of the plate-like portion 25 is a second wall portion S2 corresponding to a first wall portion S1 (described later) of the base portion 44. The plate-like portion 25 also includes a pair of holes 26 for inserting the pair of claws 23 therethrough. The first and second openings 22a, 22b of the auxiliary member 2b individually control the flow resistance of the first and second fuel gas flow paths 8a, 8b, respectively, whereas the third opening 22c is located upstream of the first and second openings 22a, 22b and controls the overall flow resistance of the first and second fuel gas flow paths 8a, 8b. The opening areas of the first to third openings 22a-22c are each set to an area that appropriately corresponds to the type of fuel gas supplied to the premixing device A, and consideration is given to ensuring that the fuel gas passing through these openings 22a-22c is an appropriate flow rate.

[0045] The sealing member 7 is a sheet-like packing having appropriate elasticity. However, the sealing member 7 is provided with holes 74a and 74b through which the cylindrical portions 24a and 24b of the auxiliary member 2b are inserted, and a pair of holes 76 through which the pair of claw portions 23 are inserted.

[0046] When the flow path adjustment member 2 is assembled with the auxiliary member 2b overlapping one end side of the main body member 2a and the seal member 7 further overlapping the second wall surface portion S2 side, which is the rear surface portion of the auxiliary member 2b, the engaging portions 23a of the pair of claw portions 23 engage with the periphery of the hole portion 76 of the seal member 7. This maintains the assembled state of the three members of the flow path adjustment member 2, namely the main body member 2a, the auxiliary member 2b, and the seal member 7, and produces an assembly AS for flow path adjustment in which these are unitized.

[0047] As can be clearly seen in FIGS. 4 and 5, a first recess 45a is provided in the base portion 44 of the premixing flow path forming member 4, with an opening at the front (opening on the left side in FIGS. 4 and 5). This first recess 45a is a portion into which the rear portion of the flow rate adjusting assembly AS is fitted. The wall surface portion on the back side of the first recess 45a (the wall surface portion on the center side of the premixing flow path forming member 4) is a first wall surface portion S1 that comes into contact with the seal member 7 when the assembly AS is fitted into the first recess 45a. As can be clearly seen in FIG. 5(b), this first wall surface portion S1 is provided with a pair of second recesses 45b into which the pair of claws 23 can enter, and the claws 23 and Undue interference with the first wall surface portion S1 is avoided.

[0048] When the rear portion of the flow rate adjustment assembly AS is fitted into the first recess 45a, the front portion of the assembly AS protrudes forward of the first recess 45a. In contrast, the pipe fitting 9 has a third recess 9a into which the front portion of the assembly AS can fit. When the pipe fitting 9 is attached to the base 44, as shown in FIGS. 4(a) and 5(a), the flow rate adjustment assembly AS is fixedly attached to the base 44 so as to be sandwiched between the pipe fitting 9 and the base 44. In this attached state, the third opening 22c communicates with the interior of the pipe fitting 9. Furthermore, the cylindrical portions 24a and 24b, which form the first and second openings 22a and 22b, extend into the tip openings of the first and second fuel gas flow paths 8a and 8b. The seal member 7 is sandwiched and pressed between the first and second wall surface portions S1 and S2 that face each other.

[0049] Next, the operation of the premixing device A and the combustion device B equipped with the same will be described.

[0050] The premixing device A is provided with a flow rate adjusting assembly AS in which the flow path adjusting member 2 and the seal member 7 are assembled, and the first to third openings 22a to 22c of this assembly AS are set to have opening areas corresponding to the type of fuel gas actually supplied to the premixing device A. Therefore, it is possible to control the flow path resistance of the fuel gas flow path 8 (first and second fuel gas flow paths 8a, 8b) and make the fuel gas flow rate in the fuel gas flow path 8 appropriate for the type of fuel gas. Therefore, it is possible to adjust the air-fuel ratio of the mixture to an appropriate ratio corresponding to the type of fuel gas, and improve combustibility in the burner section 12. In addition to these effects, the following further effects are obtained.

[0051] That is, when the flow path adjustment assembly AS is installed, the seal member 7 is sandwiched and pressed between the first wall surface S1 of the base portion 44 and the second wall surface S2 of the flow path adjustment member 2, and excellent sealing is achieved in this portion. Therefore, it is possible to achieve a highly reliable prevention of fuel gas leakage.

[0052] The flow path adjustment member 2 and the seal member 7 can be handled as a unit as a flow path adjustment assembly AS, and the work of attaching and detaching the premixing flow path forming member 4 to and from the base portion 44 can be performed all at once. Unlike the present embodiment, if the flow path adjustment member 2 and the seal member 7 were left separate, for example, it would be necessary to attach them to the base portion 44 in order, which would be a cumbersome task. In contrast, the present embodiment does not require such complication and is convenient.

[0053] To assemble the flow path adjusting member 2 and the seal member 7 into the assembly AS, it is sufficient to stack the main body member 2a of the flow path adjusting member 2, the auxiliary member 2b, and the seal member 7, and this operation is easy. When stacking these three components, it is necessary to insert the pair of claws 23 into the hole 26 of the auxiliary member 2b and the hole 76 of the seal member 7, respectively, but this operation is also easy. Furthermore, when this operation is performed, the engaging portions 23a of the pair of claws 23 automatically engage with the seal member 7, maintaining the assembled state of the three components. Because the three components cannot be easily separated, the handleability of the assembly AS can be further improved.

[0054] Furthermore, if the three components are not properly stacked, for example, due to operator error, and the seal member 7 is not properly stacked, the assembly AS of the flow path adjusting member 2 will not be properly produced, and the main body member 2a and the auxiliary member 2b of the flow path adjusting member 2 will simply be close together in a disjointed state. If the flow path adjusting member 2 or the sealing member 7 is not properly aligned, the three components will not be properly overlapped. This allows the worker to easily detect such a situation and eliminates the risk of the flow path adjusting member 2 or the sealing member 7 being attached to the base portion 44 in an inappropriate state, or for example, with the sealing member 7 missing.

[0055] When attaching the flow path adjustment assembly AS to the base portion 44 of the premixing flow path forming member 4, there is no need to screw the assembly AS to the base portion 44 by itself; the attachment of the assembly AS can be completed at the same time as the work of attaching the pipe joint portion 9 to the base portion 44. Therefore, the work of attaching and removing the flow path adjustment assembly AS to the base portion 44 can be performed more efficiently.

[0056] When attaching the assembly AS to the base portion 44, the work is made even easier because the rear portion of the assembly AS is fitted into the first recess 45a to be temporarily held therein, and then the pipe fitting portion 9 is attached to the base portion 44. Furthermore, when removing the assembly AS from the base portion 44, if the pipe fitting portion 9 is removed from the base portion 44 first, the front portion of the assembly AS protrudes forward from the first recess 45a of the base portion 44. Therefore, the assembly AS can be easily removed from the first recess 45a by grasping this protruding portion.

[0057] When the premixing device A is actually used, the type of fuel gas may be changed to a fuel gas different from the fuel gas originally planned. In this case, for example, at the installation site of the premixing device A, it becomes necessary to replace the flow path adjustment member 2 with another flow path adjustment member that is compatible with the changed fuel gas. In contrast, in this embodiment, as described above, the flow path adjustment member 2 can be easily attached and removed, making it suitable for such a case.

[0058] The sealing member 7 is a member that is strongly pressed against the first wall surface portion S1 of the base portion 44. For this reason, as shown in FIG. 13 , even if the main body member 2a and the auxiliary member 2b of the flow path adjusting member 2 are removed from the base portion 44, the sealing member 7 may remain in close contact with the first wall surface portion S1. In this case, a tool 87 for peeling the sealing member 7 can be inserted from the hole portion 76 into the second recessed portion 45b, and part of the tool 87 can be brought into contact with the periphery of the opening on the rear side of the hole portion 76 of the sealing member 7, thereby peeling off the sealing member 7. The second recessed portion 45b can also be used for such a purpose.

[0059] In this premixing device A, when the driving speed of the fan 1 is low and the air flow rate in the premixing channel 3 is low, the flapper 5 is closed as shown in FIG. 4, the first channel 3a is blocked, and air flows through the second channel 3b. This increases the speed of the air flow in the second channel 3b, creating a strong negative pressure at the second fuel gas outlet 80b, allowing an appropriate amount of fuel gas corresponding to the air flow rate to flow into the second channel 3b. On the other hand, when the driving speed of the fan 1 is high, the flapper 5 is open, allowing sufficient air to flow through both the first and second channels 3a and 3b, allowing an appropriate amount of fuel gas corresponding to the air flow rate to flow out of both the first and second fuel gas outlets 80a and 80b. This allows for a high turndown ratio.

[0060] 14 and 15 show another embodiment of the present invention. In these figures, elements that are the same as or similar to those in the previous embodiment are given the same reference numerals as in the previous embodiment, and duplicated explanations will be omitted.

[0061] 14, the flow path adjusting member 2A has a cylindrical wall portion 20a whose inner region constitutes part of the fuel gas flow path 8, and a third opening 22c is provided in a front wall portion 20b of the cylindrical wall portion 20a. The flow path adjusting member 2 is provided with cylindrical portions 24a and 24b that form the openings 22a and 22b, and a flange portion 25b having a second wall surface portion S2. The flow path adjusting member 2 is also provided with a pair of claw portions 23. The flow path adjusting member 2A of this embodiment corresponds to a configuration in which the main body member 2a and the auxiliary member 2b of the flow path adjusting member 2 of the above embodiment are integrated together. This configuration reduces the total number of parts, thereby reducing costs and improving ease of handling.

[0062] 15, a flow path adjusting member 2B has a notch 26a provided in an auxiliary member 2b, into which the claw 23 can be inserted. The sealing member 7 also has a notch 76a provided therein, into which the claw 23 can be inserted. The notches 26a, 76a replace the holes 26, 76 provided in the auxiliary member 2b and the seal member 7 of the above-described embodiment. In the present invention, the configuration as in this embodiment can also be used.

[0063] The present invention is not limited to the above-described embodiment, and the specific configurations of the premixing device and each part of the combustion device according to the present invention can be freely designed and modified in various ways within the intended scope of the present invention.

[0064] In the above-described embodiment, the premixing channel is divided into first and second channel, and a flapper is provided in the first channel, but the present invention is not limited to this. The present invention can also be configured as a premixing device of a type that does not include a flapper and in which the premixing channel is not divided into multiple channel, as shown in Patent Document 1, for example. The specific shape, size, material, etc. of the flow path adjustment member can be changed in various ways. The claw portion does not have to be a pair, and a configuration in which only one or three or more are provided is also possible. Furthermore, it is sufficient that at least one opening (corresponding to the above-mentioned first to third openings) is provided to accommodate the type of fuel gas in the fuel gas flow path. The opening of the flow path adjustment member is set to an opening area corresponding to the type of fuel gas, but the specific value is not limited. Typical examples of fuel gas types include natural gas and LP gas, but the present invention is not limited to these and other types of fuel gases can also be used. The combustion apparatus according to the present invention is not limited to a water heater, but can be used for other purposes such as heating, incineration, etc. Furthermore, it is not limited to a type in which the combustion gas flows downward, but can also be a type in which the fuel gas flows upward, for example. [Explanation of symbols]

[0065] A Premixer B. Combustion device S1, S2 First and second wall sections 2, 2A, 2B Flow path adjustment member 2a Main body member (flow path adjusting member) 2b Auxiliary member (for flow path adjustment member) 22a to 22c First and second openings (of the flow path adjusting member) 23 Claw 23a Engagement part (claw part) 26 Hole (of auxiliary member) 26a Notch (of auxiliary member) 3 Premixing channel 3a, 3b First and second flow paths 4 Premixing flow path forming member 44 base portion (of premixing flow path forming member) 45a, 45b First and second recesses 7 Sealing material 76 Hole (of sealing member) 76a Notch (of sealing member) 8 Fuel gas flow path 8a, 8b First and second fuel gas flow paths (fuel gas flow paths) 80a, 80b First and second fuel gas outlets (fuel gas outlets) 9 Pipe joint 99 Gas Pipe

Claims

1. a premixing flow path forming member that forms a premixing flow path for allowing air to flow from one end side to the other end side and for mixing the air with fuel gas; a base portion provided in the premixing flow passage forming member for mounting a pipe joint portion to which a gas pipe for supplying the fuel gas is connected; a fuel gas flow path, the terminal end of which is formed as a fuel gas outlet for discharging the fuel gas into the premixing flow path, and which guides the fuel gas supplied to the pipe joint portion to the fuel gas outlet; a flow path adjusting member having an opening that forms a part of the fuel gas flow path, the opening having an opening area set to correspond to the type of fuel gas; a sealing member for sealing the attachment portion of the flow path adjusting member; A premixing device comprising: the base portion is provided with a first wall surface portion, which serves as a portion facing the flow path adjustment member, and which has an opening in a portion of the fuel gas flow path; the flow path adjustment member has a claw portion that can hold the sealing member on a second wall surface portion on a rear surface side of the flow path adjustment member, the pipe fitting portion can be attached to the base portion in a state in which the flow path adjusting member is sandwiched between the first and second wall surface portions so that the sealing member is pressed between the first and second wall surface portions.

2. 10. The premixing device of claim 1, The flow path adjusting member is a main body member having a cylindrical wall portion whose inner region constitutes a part of the fuel gas flow path and the claw portion protruding from one end side of the cylindrical wall portion; an auxiliary member that is overlapped on the one end side of the cylindrical wall portion and has a hole portion or a notch portion through which the opening portion, the second wall surface portion, and the claw portion are inserted; It is equipped with the seal member is placed on the second wall surface portion of the auxiliary member so that the auxiliary member is sandwiched between the main body member and the seal member, and is engaged with an engaging portion provided on the tip end side of the claw portion.

3. 10. The premixing device of claim 1, the flow path adjustment member includes a cylindrical wall portion whose inner region constitutes part of the fuel gas flow path, and the second wall surface portion, in which the opening is provided, and the claw portion are integrally molded with the cylindrical wall portion.

4. 10. The premixing device of claim 1, a first recess having a front opening is provided in the base portion, and a rear portion of the flow path adjustment member can be fitted into the first recess; a premixing device configured such that, when the pipe joint portion is detached from the base portion, a front portion of the flow path adjustment member protrudes outward and forward from the base portion.

5. 10. The premixing device of claim 1, a second recess into which the claw can enter, is provided in the first wall surface of the base.

6. 10. The premixing device of claim 1, a partition wall portion that divides the premixing flow path into first and second flow paths arranged in parallel, And, the fuel gas flow path branches into first and second fuel gas flow paths, and the first and second fuel gas flow paths have, as the fuel gas outlets, first and second fuel gas outlets that are provided to allow the fuel gas to flow into the first and second flow paths, a premixing device, wherein the openings of the flow path adjustment member include first and second openings corresponding to the first and second fuel gas flow paths;

7. 7. The premixing device of claim 6, the flow path adjustment member includes a cylindrical wall portion whose inner region constitutes a part of the fuel gas flow path, the flow path adjustment member is provided with a third opening located upstream of the first and second openings in the fuel gas flow direction, and the fuel gas passing through the third opening proceeds to the first and second openings.

8. A combustion device comprising the premixing device according to any one of claims 1 to 7.

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