JP7480467B2 - Premixing device and combustion device equipped with the same - Google Patents

Description

The present invention relates to a premixing device and a combustion device including 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.

A specific example of a premixing device is described in Patent Document 1.
The premixing device described in this document includes a tubular member (premixing passage forming member) that forms a Venturi-shaped premixing passage, and two blade sections, one vertical and one horizontal, that are attached inside the tubular member. The intake side of a fan is connected to the downstream side (terminal end side) of the premixing passage, and air flows into the premixing passage from its upstream side (starting end side). A fuel gas outlet is provided in the blade section, and when air flows into the premixing passage and negative pressure is generated, the negative pressure causes fuel gas to flow out from the fuel gas outlet into the premixing passage and mix with the air.

However, there is room for improvement in the above-mentioned conventional technology, as described below.

That is, the fuel gas used in the premixer is not one type, but generally one of two types of fuel gas, natural gas and LP gas, is used. However, since these two types of fuel gas have different components and heating values, the premixer must be compatible with the type of fuel gas.
Specifically, the premixing device is provided with a fuel gas flow passage for guiding the fuel gas from the outside of the premixing flow passage forming member to the fuel gas outlet, and this fuel gas flow passage needs to correspond to the type of fuel gas. When the negative pressure generated in the premixing flow passage is the same, the fuel gas with a lower heating value must be set so that it flows out in a larger amount from the fuel gas outlet into the premixing flow passage than a fuel gas with a higher heating value, and the premixing device needs to be designed to meet such specifications.

However, no simple and appropriate means for dealing with the above-mentioned problems has been proposed in the past. Conventionally, parts corresponding to the type of fuel gas are manufactured and prepared in advance, and when a type of fuel gas different from the planned fuel gas is used, measures such as replacing the parts or adding new parts have been adopted.
However, this requires replacement or additional parts, and the number of these parts in stock increases, which increases the cost. In addition, parts management becomes troublesome. Furthermore, when a part is replaced, there is a risk that the replaced part will become unnecessary.

JP 11-502278 A

The present invention was conceived under the circumstances described above, and its objective is to provide a premixing device that can appropriately handle multiple types of fuel gas without the need to replace parts or add new parts depending on the type of fuel gas, and a combustion device equipped with the same.

To solve the above problems, the present invention provides the following technical solutions:

A premixing device provided according to a first aspect of the present invention comprises: a premixing flow path forming member forming a premixing flow path for flowing air from one end side to the other end side and mixing a fuel gas with the air; and a fuel gas flow path having a fuel gas supply port for receiving a supply of the fuel gas from an outside and a fuel gas outlet opening into the premixing flow path and for guiding the fuel gas supplied to the fuel gas supply port to the fuel gas outlet, the premixing device further comprising a fuel gas flow path adjusting member that is directly or indirectly attached to the premixing flow path forming member and is capable of blocking a part of the fuel gas flow path, the attachment manner of the fuel gas flow path adjusting member is changeable, and by changing the attachment manner, the position and/or area at which the fuel gas flow path adjusting member blocks the fuel gas flow path can be changed, making it possible to change the flow path resistance of the fuel gas flow path, the fuel gas flow path adjustment member is configured to be attached to the fuel gas flow path in a manner that can be selectively set to either a first installation manner in which the fuel gas flow path corresponds to the first fuel gas, or a second installation manner in which the fuel gas flow path corresponds to the second fuel gas; the fuel gas flow path adjustment member is further provided with first and second gas type display units indicating the first and second fuel gases, respectively; when the fuel gas flow path adjustment member is set to the first installation manner, the second gas type display unit is covered and concealed by the fuel gas flow path adjustment member and the first gas type display unit is exposed; on the other hand, when the fuel gas flow path adjustment member is set to the second installation manner, the first gas type display unit is covered and concealed by the fuel gas flow path adjustment member and the second gas type display unit is exposed .
Here, "the mounting manner of the fuel gas flow path adjustment member is changeable" corresponds to a case where at least one of the mounting position, orientation, angle, or posture of the fuel gas flow path adjustment member is changeable.
The "area blocking the fuel gas flow passage is changed" also includes a case where the area blocking the fuel gas flow passage is changed to zero.

According to this configuration, the following effects can be obtained.
That is, by changing the mounting manner of the fuel gas flow path adjusting member and changing the area of the fuel gas flow path that the fuel gas flow path adjusting member blocks, it is possible to change the flow path resistance of the fuel gas flow path. For example, in the case of a fuel gas with a large calorific value, the area that blocks the fuel gas flow path is increased to set the flow path resistance to a large value, and in the case of a fuel gas with a small calorific value, the area that blocks the fuel gas flow path is decreased to set the flow path resistance to a small value, thereby making it possible to maintain the mixture ratio of air and fuel gas within an appropriate range.
For this reason, according to the present invention, when the type of fuel gas differs from the expected type of fuel gas, it is not necessary to replace the fuel gas flow path adjusting member with another member, and it is also not necessary to use a new part separately. Therefore, there is no inconvenience of having to stock a large number of parts to accommodate the type of fuel gas, the cost required for stocking parts can be reduced, and parts management can be made easier. When replacing parts, the original parts may become unnecessary, but according to the present invention, there is no such waste.
In addition, with this configuration, depending on whether the fuel gas used for premixing is the predetermined first or second fuel gas, the fuel gas flow path adjusting member can be set to the corresponding side of either the first or second mounting manner, thereby making it possible to facilitate and optimize the setting work of the fuel gas flow path adjusting member.
Furthermore, according to this configuration, the gas type display unit that is not covered by the fuel gas flow path adjusting member and is exposed indicates whether the fuel gas to which the installation mode of the fuel gas flow path adjusting member corresponds is the first or second fuel gas. Therefore, it is possible to easily and quickly confirm whether the type of fuel gas actually used corresponds to the installation mode of the fuel gas flow path adjusting member. For example, it is possible to appropriately prevent a fuel gas flow path adjusting member from being erroneously determined to be installed in a manner corresponding to the second fuel gas (second installation mode) even though the installation mode (first installation mode) corresponds to the first fuel gas.

In the present invention, the fuel gas is preferably caused to flow out from the fuel gas outlet into the premixing channel by the action of negative pressure generated by airflow in the premixing channel.
The present invention is ideal for a premixing device having such a configuration.

A premixing device provided according to a second aspect of the present invention includes 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, and a fuel gas flow path that has a fuel gas supply port that receives a supply of the fuel gas from an outside and a fuel gas outlet that opens into the premixing flow path and guides the fuel gas supplied to the fuel gas supply port to the fuel gas outlet, the premixing device further including a fuel gas flow path adjusting member that is directly or indirectly attached to the premixing flow path forming member and is capable of blocking a part of the fuel gas flow path. the fuel gas flow path adjustment member is attached in a variable manner, and by changing the attachment manner, the position and/or area at which the fuel gas flow path adjustment member blocks the fuel gas flow path can be changed, thereby changing the flow resistance of the fuel gas flow path; the fuel gas flow path adjustment member further comprises a pipe coupling portion having a cylindrical portion with an open tip for connecting a gas pipe for supplying the fuel gas, the fuel gas supply port is provided on an inner wall portion within the cylindrical portion, and the fuel gas flow path adjustment member is inserted into the cylindrical portion from the open tip and attached to the inner wall portion using a fastening member .

With this configuration, the area blocking the fuel gas supply port can be appropriately changed by a simple structure in which the fuel gas flow path adjustment member is attached to the inner wall inside the cylindrical portion of the pipe joint using a fastening member, and the intended effect of the present invention can be achieved. The attachment mode of the fuel gas flow path adjustment member can be easily changed when the gas pipe is not connected to the cylindrical portion of the pipe joint, improving workability.

A premixing device provided according to a third aspect of the present invention comprises a premixing flow path forming member forming a premixing flow path for flowing air from one end side to the other end side and mixing a fuel gas with the air, and a fuel gas flow path having a fuel gas supply port for receiving a supply of the fuel gas from an outside and a fuel gas outlet opening into the premixing flow path and for guiding the fuel gas supplied to the fuel gas supply port to the fuel gas outlet, the premixing device further comprising a fuel gas flow path adjusting member that is directly or indirectly attached to the premixing flow path forming member and is capable of blocking a part of the fuel gas flow path, the attachment manner of the fuel gas flow path adjusting member is changeable, and by changing the attachment manner, the position at which the fuel gas flow path adjusting member blocks the fuel gas flow path can be changed. and/or the area thereof can be changed to change the flow path resistance of the fuel gas flow path, a portion of the fuel gas flow path closer to the fuel gas supply port is divided into a plurality of parallel flow paths, and a plurality of fuel gas supply ports corresponding to the plurality of parallel flow paths are provided as the fuel gas supply ports, the position and/or number at which the fuel gas flow path adjustment member blocks the plurality of fuel gas supply ports is changeable, the plurality of parallel flow paths include first and second parallel flow paths having different flow path areas, and the plurality of fuel gas supply ports include first and second fuel gas supply ports corresponding to the first and second flow paths, and the fuel gas flow path adjustment member is capable of selectively blocking one of the first and second fuel gas supply ports.

In this configuration, the fuel gas flow path is divided into multiple parallel flow paths and has multiple fuel gas supply ports, while the fuel gas flow path adjustment member only needs to be attached so that the position and/or number of the multiple fuel gas supply ports that it blocks can be changed. This allows for a simple overall configuration, and also makes it possible to easily change the installation mode of the fuel gas flow path adjustment member.

In addition , with this configuration, since the flow area of the first and second parallel flow paths is different, the flow resistance of the fuel gas flow path differs depending on which of the corresponding first and second fuel gas supply ports is blocked by the fuel gas flow path adjusting member, which makes it possible to further facilitate and optimize the flow resistance of the fuel gas flow path to appropriately correspond to the type of fuel gas.

In the present invention, preferably, the portions of the first and second parallel flow paths near the first and second fuel gas supply ports are made to be the same in shape and size, and the fuel gas flow path adjustment member has a sealing convex portion that can be fitted into the portions near the first and second fuel gas supply ports.

With this configuration, when blocking either the first or second fuel gas supply port, the sealing convex portion can be fitted into this portion. Therefore, fuel gas leakage can be appropriately prevented. Although the first and second parallel flow paths are basically flow paths with different flow path areas, the portions closer to the first and second fuel gas supply ports are made to have the same shape and size, so that the sealing convex portion can be appropriately fitted into either of these portions in a highly airtight state.

A combustion device provided according to a fourth aspect of the present invention is characterized by comprising the premixing device provided according to any one of the first to third aspects of the present invention.

According to such a configuration, the same effects as those described for the premixing device provided according to any one of the first to third aspects of the present invention can be obtained.

Other features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment of the invention, taken in conjunction with the accompanying drawings.

1 is an explanatory diagram showing an example of a combustion apparatus equipped with a premixing device according to the present invention, and a hot water supply apparatus using the same. FIG. 2 is a cross-sectional view taken along line II-II of FIG. FIG. 3 is an external perspective view of the premixing device shown in FIGS. 1 and 2 . 4A is a cross-sectional view taken along line IV-IV in FIG. 3, and FIG. 4B is an exploded cross-sectional view of FIG. This is a cross-sectional view taken along line VV of Figure 4. FIG. 4 is a front view of a main portion of the premixing device shown in FIG. 3 . FIG. 7 is an exploded front view of the main part of FIG. 6 . 7 is a front view of a main portion showing an example in which a fuel gas flow path adjusting member is set in an embodiment different from that shown in FIG. 6. 9A and 9B show a fuel gas flow path adjusting member used in the premixing device shown in FIGS. 1 to 8, in which FIG. 9A is a perspective view from the outer surface side, and FIG. 9B is a perspective view from the inner surface side. FIG. 2 is an external perspective view showing another example of a premixing device according to the present invention. 10A is a cross-sectional view taken along line XI-XI of FIG. 10, and FIG. 10B is an exploded cross-sectional view of a main portion of FIG. FIG. 11 is a front view of a main portion of the premixing device shown in FIG. 10. FIG. 13 is an exploded front view of the main part of FIG. 12 . 13 is a front view of a main portion showing an example in which a fuel gas flow path adjusting member is set in an embodiment different from that shown in FIG. 12 . FIG. 15 is a perspective view showing the inner surface side of a fuel gas flow path adjusting member used in the premixing device shown in FIGS. 10 to 14. FIG. 4 is a front view of a main portion showing another example of a premixing device according to the present invention. 17A is a cross-sectional view taken along line XVII-XVII of FIG. 16, and FIG. 17B is an exploded cross-sectional view of a main portion of FIG. FIG. 17 is an exploded front view of the main part of FIG. 16 . 17 is a front view of a main portion showing an example in which a fuel gas flow path adjusting member is set in an embodiment different from that shown in FIG. 16. FIG. 4 is an exploded front view of a main portion showing another example of a premixing device according to the present invention. 21A and 21B are front views of the essential part showing a state in which a fuel gas flow path adjusting member is attached to the configuration shown in FIG. 20. FIG. 4 is a front view of a main portion showing another example of a premixing device according to the present invention. 23 is a cross-sectional view of the main part taken along the line XXIII-XXIII in FIG. 22 . FIG. 23 is an exploded front view of the main part of FIG. 22 . 23 shows an example in which a fuel gas flow path adjusting member is set in an embodiment different from that shown in FIG. 22, where (a) is a front view of a main portion, and (b) is a cross-sectional view taken along the line XXV-XXV of (a). 2A and 2B show another example of a premixing device according to the present invention, in which FIG. 2A is a front view of a main portion, and FIG. 2B is a cross-sectional view taken along the line XXVI-XXVI of FIG. FIG. 27 is an exploded front view of the main part of FIG. 26(a). 27A and 27B show an example in which a fuel gas flow path adjusting member is set in an embodiment different from that shown in FIG. 26, where FIG. 27A is a front view of a main portion, and FIG. 27B is a cross-sectional view taken along the line XXVIII-XXVIII of FIG. 26A. FIG. 4 is an exploded cross-sectional view showing a main part of another example of a premixing device according to the present invention.

The preferred embodiment of the present invention will be described in detail below with reference to the drawings.

Figure 1 shows a premixing device A, a combustion device B (premixed combustion device) formed by combining this premixing device A with a fan 1 and a combustion plate 2, and a hot water supply device WH formed by combining this combustion device B with a heat exchanger 11.

Details of the premixing device A will be described later, but this premixing device A is used to generate a mixed gas (combustible mixed gas) of air and fuel gas, and this mixed gas is discharged toward the combustion plate 2 via the fan 1. The combustion plate 2 is a porous plate with multiple air holes 20 and is housed in a case 10, and the mixed gas passes through the combustion plate 2 and is burned below it. The combustion gas generated by this acts on the heat exchanger 11, and the hot water passing through the heat exchanger 11 is heated. This generates hot water, which is supplied to the desired hot water supply destination.

The premixing device A includes a premixing flow path forming member 4 having a tubular portion 41 that forms the premixing flow path 40, a housing member 5 attached to the premixing flow path forming member 4, blade portions 6 each having a fuel gas outlet 74, a fuel gas flow path 7 including the fuel gas outlet 74, and a fuel gas flow path adjusting member 8 shown in Figures 3 to 9.

The premix flow passage forming member 4 is connected to the intake side of the fan 1, and when the fan 1 is driven, external air flows into the premix flow passage 40 from one end opening. The premix flow passage 40 has a venturi shape in which the upstream region in the gas flow direction is a tapered region in which the inner diameter gradually decreases toward the downstream side in the gas flow direction, and the region downstream of this tapered region is a tapered region in which the inner diameter gradually increases toward the downstream side.

Each blade portion 6 functions as a nozzle for discharging fuel gas from the fuel gas outlet 74 into the premix flow passage 40, and as shown in FIG. 2, it is connected to the peripheral wall of the tubular portion 41 at both ends in a bridge shape and is located within the premix flow passage 40. A pair of blade portions 6 are arranged approximately parallel to each other with an appropriate gap in their thickness direction (left-right direction in FIG. 1).

The interior of each blade portion 6 is a cavity 73 that forms part of the fuel gas flow passage 7, and this cavity 73 is connected to a fuel gas outlet 74. Meanwhile, the air flow in the premixing flow passage 40 generates negative pressure in the vicinity of the fuel gas outlet 74. Due to the action of this negative pressure, the fuel gas flows out from the fuel gas outlet 74 into the premixing flow passage 40, and the air and fuel gas are mixed.
The number of blade portions 6 is not limited to two, and may be one or three or more.

The housing member 5 includes a cylindrical housing body 50, a pipe joint 51 that is provided integrally with the housing body 50 or separately, and a flange 53 that is provided with a bolt insertion hole 52. The flange 53 is useful for easily and appropriately connecting the premixing device A to a desired location.

The housing body 50 fits over the steps 42a, 42b on the outer periphery of the premix flow passage forming member 4, and surrounds the premix flow passage forming member 4 with an airtight seal provided by a sealing ring 49. The region 72 between the premix flow passage forming member 4 and the housing body 50 forms part of the fuel gas flow passage 7.

The pipe joint 51 is a portion to which the gas pipe 9 (including the hose) that supplies the fuel gas is connected, and the fuel gas supplied from the gas pipe 9 to the pipe joint 51 flows into the aforementioned region 72. As shown in FIG. 2, the premix flow passage forming member 4 has an opening 43 that communicates with a cavity 73 in each blade portion 6. The fuel gas that flows into the aforementioned region 72 passes through the opening 43 and flows into each blade portion 6, and as described above, flows out from the fuel gas outlet 74.

Describing the pipe joint portion 51 in more detail, the pipe joint portion 51 has a cylindrical portion 51a with an open tip, and at the back of the cylindrical portion 51a, an inner wall portion 51b having a fuel gas supply port 70 is provided.
The fuel gas flow passage 7 is a flow passage that guides the fuel gas from a fuel gas supply port 70 to a fuel gas outlet 74. However, as shown in Figures 4 to 8, the pipe joint part 51 is provided with first and second parallel flow passages 71A, 71B that form part of the fuel gas flow passage 7, which are arranged side by side at an appropriate interval, and first and second fuel gas supply ports 70a, 70b are provided as openings thereof.

4, the first and second parallel flow paths 71A and 71B have different inner diameters Da and Db, and the relationship is Da<Db. The inner diameter Da is a flow path inner diameter suitable for use with LP gas as the fuel gas. The inner diameter Db is a flow path inner diameter suitable for use with natural gas as the fuel gas.
However, the inner diameter Dc of the portion (the portion near the first and second fuel gas supply ports 70a, 70b) into which the sealing convex portion 83 of the fuel gas flow path adjustment member 8 described later is inserted is larger than the inner diameters Da, Db described above and are made to be the same dimension.

As shown in FIG. 7, the inner wall 51b of the pipe joint 51 is also provided with first and second gas type indicators 3a, 3b and two screw holes 59. The first and second gas type indicators 3a, 3b are provided near the upper or lower sides of the first and second fuel gas supply ports 70a, 70b, respectively, and are indicators that indicate that the first and second fuel gas supply ports 70a, 70b are compatible with LP gas and natural gas, respectively. For example, these are the letters "LP" and "NG". However, different indications may also be used.

The fuel gas flow path adjusting member 8 is a member for selectively closing either one of the first and second fuel gas supply ports 70a, 70b depending on the type of fuel gas. As shown in Fig. 9, for example, the fuel gas flow path adjusting member 8 includes a semicircular plate-shaped main body 80, which is provided with a knob 81, a threaded body insertion hole 82, and a sealing convex portion 83. As shown in Figs. 4 and 5, a sealing O-ring 84 is fitted onto the sealing convex portion 83.

As shown in Figures 4 to 6, the fuel gas flow path adjustment member 8 is attached to the inner wall portion 51b of the pipe joint portion 51 in a manner (first installation manner) in which the first fuel gas supply port 70a is blocked. This installation is performed using a screw body 98 (fastening member) such as a screw that screws into the screw hole 59. In this first installation manner, the sealing convex portion 83 is fitted into the first fuel gas supply port 70a, and the second gas type display portion 3b is covered and hidden by the fuel gas flow path adjustment member 8. The first gas type display portion 3a is not covered and hidden by the fuel gas flow path adjustment member 8, and is exposed to the front of the pipe joint portion 51.

The fuel gas flow path adjustment member 8 can be attached to the inner wall portion 51b of the pipe joint portion 51 in a manner (second attachment manner) in which the second fuel gas supply port 70b is blocked, as shown in FIG. 8. The first attachment manner can be changed to the second attachment manner by loosening the fastening state by the screw body 98, removing the fuel gas flow path adjustment member 8 from the inner wall portion 51b, and then reattaching the fuel gas flow path adjustment member 8 to the inner wall portion 51b using the screw body 98 in an upside-down position. In the second attachment manner, the sealing convex portion 83 is fitted into the second fuel gas supply port 70b, and the first gas type display portion 3a is covered by the fuel gas flow path adjustment member 8, and the second gas type display portion 3b is exposed to the front of the pipe joint portion 51, in contrast to the first attachment manner.

Next, we will explain the operation of the premixing device A.

First, in the environment in which the premixing device A is used, when the fuel gas is, for example, natural gas, the fuel gas flow path adjustment member 8 is set in the first installation mode as shown in Figures 3 to 6. As a result, the first parallel flow path 71A is blocked by the fuel gas flow path adjustment member 8, and the second parallel flow path 71B becomes an effective flow path that forms a part of the fuel gas flow path 7. As described above, the inner diameter Db of the second parallel flow path 71B corresponds to natural gas. Since natural gas has a smaller calorific value than LP gas, it is necessary to increase the amount of gas relative to air compared to when LP gas is used, but the first installation mode can appropriately respond to such a need. In other words, the second parallel flow path 71B has a larger inner diameter than the first parallel flow path 71A, and the flow path resistance of the fuel gas flow path 7 can be reduced, so that it is possible to cause a larger amount of natural gas to flow out of the fuel gas outlet 74 due to the negative pressure action generated by the air flow in the premixing flow path 40.

In contrast to the above, when the fuel gas is LP gas, the second installation mode as shown in FIG. 8 may be used. As described above, the first installation mode can be easily and quickly changed to the second installation mode by loosening the screw body 98. In the second installation mode, the second parallel flow path 71B is blocked, and the first parallel flow path 71A becomes an effective flow path that forms part of the fuel gas flow path 7, in contrast to the first installation mode. As described above, the inner diameter Da of the first parallel flow path 71A corresponds to LP gas. Since LP gas has a higher calorific value than natural gas, it is necessary to reduce the amount of gas relative to air, and the second installation mode can appropriately deal with such a situation.

As described above, according to this embodiment, whether the fuel gas is natural gas or LP gas, there is no need to replace parts or add and install new parts, and it is possible to appropriately handle the type of fuel gas simply by changing the installation mode of the fuel gas flow path adjustment member 8. Therefore, there is no inconvenience such as an increase in the number of parts in stock to handle the type of fuel gas, and the cost required for stocking parts can be reduced.
In addition, parts management becomes easier.

According to this embodiment, when the fuel gas flow path adjusting member 8 is attached in the first manner, the second gas type display portion 3b is covered, but the letters "NG" in the first gas type display portion 3a remain visible. Conversely, when the fuel gas flow path adjusting member 8 is attached in the second manner, the first gas type display portion 3a is covered, and the letters "LP" in the second gas type display portion 3b are visible. Therefore, by checking such indications, it is possible to easily and accurately determine whether the attachment mode of the fuel gas flow path adjusting member 8 is appropriate for the actual type of fuel gas.
In addition, since the fuel gas flow path adjustment member 8 is formed as a small piece overall and is attached inside the pipe joint portion 51, the fuel gas flow path adjustment member 8 does not become large and bulky, and it is also possible to prevent the premixing device A from becoming large.

Figures 10 to 29 show other embodiments of the present invention. In these figures, elements that are the same as or similar to those in the above embodiment are given the same reference numerals as in the above embodiment, and duplicate explanations will be omitted.

10 to 14, a plurality of (for example, four) parallel flow paths 71 are provided in the inner wall portion 51b of the pipe joint portion 51, and a plurality of fuel gas supply ports 70 are arranged concentrically as openings thereof. A screw hole 59 is provided in the center of the inner wall portion 51b, and a plurality of positioning recesses 58 are provided around the screw hole 59.
15 , the fuel gas flow path adjusting member 8A has a disk-shaped main body 80 with elongated hole-shaped openings 85, the same number as the fuel gas supply ports 70, penetrating therethrough, and a plurality of positioning protrusions 86 protruding from the inner surface side of the main body 80. The plurality of positioning protrusions 86 are portions that fit into the plurality of recesses 58 and serve to position the fuel gas flow path adjusting member 8A when the fuel gas flow path adjusting member 8A is set to the first and second mounting modes described below.

As shown in Figures 10 to 12, the premixing device Aa of this embodiment is configured such that the fuel gas flow path adjustment member 8A is attached to the inner wall portion 51b of the pipe joint portion 51 using a screw body 98. However, when the fuel gas is natural gas, the fuel gas flow path adjustment member 8A is attached in the first manner shown in Figure 12. In this first manner, the multiple fuel gas supply ports 70 entirely overlap the multiple openings 85, and the effective opening area of the multiple fuel gas supply ports 70 is equal to the total area of the multiple openings 85.

In contrast, when the fuel gas is LP gas, the fuel gas flow path adjustment member 8A is attached in a second manner as shown in FIG. 14. In this second attachment manner, a portion of each of the multiple openings 85 overlaps with a portion that is not the fuel gas supply port 70, and the multiple openings 85 do not entirely overlap with the multiple fuel gas supply ports 70. Therefore, in this second attachment manner, the effective opening area of the fuel gas supply port 70 is smaller than in the first attachment manner shown in FIG. 12, and it is suitable for LP gas, which has a high calorific value.

To change from the first mounting mode shown in FIG. 12 to the second mounting mode shown in FIG. 14, the screw body 98 is loosened and the fuel gas flow path adjustment member 8A is rotated by an appropriate angle. In addition, at that time, the angle of the fuel gas flow path adjustment member 8A is set to a position where the multiple positioning protrusions 86 fit into the recesses 58. Therefore, the above-mentioned changing of the mounting mode is also easy.

In the premixing device Ab shown in FIGS. 16 to 19, a plurality of parallel flow passages 71 are provided on the inner wall portion 51b of the pipe joint portion 51, and a plurality of fuel gas supply ports 70 are provided as openings of the parallel flow passages 71.
are arranged on the same circle. The parallel flow paths 71 and the fuel gas supply ports 70 have smaller areas than the parallel flow paths 71 and the fuel gas supply ports 70 of the premixing device Aa of the previous embodiment, and the number of the parallel flow paths 71 and the fuel gas supply ports 70 is greater than that of the parallel flow paths 71 and the fuel gas supply ports 70 of the premixing device Aa of the previous embodiment.
The fuel gas flow path adjusting member 8B has openings 85 having substantially the same shape and size as the fuel gas supply ports 70, and the same number of openings 85 as the fuel gas supply ports 70. The fuel gas flow path adjusting member 8B also has a plurality of protrusions 86 that can be fitted into a plurality of positioning recesses 58 provided in the pipe joint portion 51.

In the premixing device Ab of this embodiment, when the fuel gas is natural gas, the fuel gas flow path adjusting member 8B is set to a first mounting mode shown in Fig. 16. In this first mounting mode, the multiple openings 85 entirely overlap the multiple fuel gas supply ports 70, and the multiple fuel gas supply ports 70 are entirely open. Therefore, this is suitable for natural gas, which has a small calorific value.
In contrast, when the fuel gas is LP gas, the fuel gas flow path adjusting member 8B is set to a second mounting mode shown in Fig. 19. In this second mounting mode, the fuel gas supply ports 70 and the openings 85 do not completely coincide with each other and overlap, and each fuel gas supply port 70 is partially blocked. Therefore, this is suitable for LP gas, which has a large calorific value.

In this embodiment, as in the premixing device Aa described above, the mounting mode of the fuel gas flow path adjustment member 8B can be changed by loosening the screw body 98 and rotating the fuel gas flow path adjustment member 8B, which is an easy task. In addition, in this case, the rotation angle of the fuel gas flow path adjustment member 8B can be conveniently set to an accurate angle by fitting the multiple protrusions 86 and recesses 58 together.

20 and 21 , a plurality of parallel flow paths 71 are provided in the inner wall portion 51b of the pipe joint portion 51, and a plurality of fuel gas supply ports 70 are provided as openings thereof. The plurality of fuel gas supply ports 70 are arranged on the same circle, but are not equally spaced apart, and have unequal interval portions 70′ (slightly wider regions where no fuel gas supply ports 70 are provided).
The fuel gas flow path adjusting member 8C has a plurality of openings 85 that are substantially the same in shape, size, and arrangement as the plurality of fuel gas supply ports 70 .

In this premixing device Ac, when the fuel gas is natural gas, the fuel gas flow path adjustment member 8C is in the first mounting mode shown in FIG. 21(a). In this first mounting mode, all of the multiple fuel gas supply ports 70 overlap with the openings 85 and are in a wide open state. In contrast, when the fuel gas is LP gas, the fuel gas flow path adjustment member 8C is in the second mounting mode shown in FIG. 21(b). In this second mounting mode, one opening 85 is located in the unequal interval portion 70', and one of the multiple fuel gas supply ports 70 is blocked by the fuel gas flow path adjustment member 8C. Therefore, even in the case of this embodiment, it is possible to appropriately respond to both cases where the fuel gas is natural gas and LP gas. The mounting mode of the fuel gas flow path adjustment member 8C can be changed by loosening the screw body 98 and rotating the fuel gas flow path adjustment member 8C, so the operation is also easy.

22 to 25, the pipe joint 51 does not have multiple parallel flow paths, but has one hole 71C that forms part of the fuel gas flow path 7. The opening of this hole 71C is the fuel gas supply port 70. This fuel gas supply port 70 is disposed offset in one direction (to the right in the drawings) from the center of the inner wall 51b of the pipe joint 51.
On the other hand, the fuel gas flow path adjusting member 8D has a disk-shaped main body 80 provided with two openings 85a, 85b having different diameters and two screw insertion holes 82.

22 and 23 show a first mounting mode of the fuel gas flow path adjustment member 8 D. In this first mounting mode, the large-diameter opening 85 a of the fuel gas flow path adjustment member 8 D overlaps with the fuel gas supply port 70.
25 shows a second mounting manner of the fuel gas flow path adjusting member 8D. In this second mounting manner, the opening 85b on the small diameter side of the fuel gas flow path adjusting member 8D overlaps with the fuel gas supply port 70.
The effective opening area of the fuel gas supply port 70 is large in the first mounting mode and is small in the second mounting mode, thereby achieving the intended effect of the present invention. To switch between the first and second mounting modes, the screw body 98 is loosened, the fuel gas flow path adjusting member 8D is temporarily removed, and then the screw body 98 is turned over and reattached, which is also an easy operation.
According to this embodiment, since there is no need to provide a plurality of parallel flow paths, the fuel gas flow path 7 can be simplified.

26 to 28, a hole 71D that forms part of the fuel gas flow path 7 is provided in the pipe joint 51. The hole 71D is an elongated hole, and its opening is a fuel gas supply port 70.
On the other hand, the fuel gas flow path adjusting member 8E has a circular opening 85 provided at a position offset from the center of the disk-shaped main body 80.

26 shows a first mounting mode of the fuel gas flow path adjusting member 8E. In this first mounting mode, the fuel gas supply port 70 is blocked by the fuel gas flow path adjusting member 8E such that substantially the entirety of the opening 85 of the fuel gas flow path adjusting member 8E faces a part of the fuel gas supply port 70.
28 shows a second mounting manner of the fuel gas flow path adjusting member 8E. In this second mounting manner, the fuel gas supply port 70 is blocked by the fuel gas flow path adjusting member 8E such that only a portion of the opening 85 of the fuel gas flow path adjusting member 8E faces a portion of the fuel gas supply port 70.

In this embodiment, as in the above embodiment, the effective opening area of the fuel gas supply port 70 is large in the first installation mode and small in the second installation mode. The first installation mode is suitable for natural gas, and the second installation mode is suitable for LP gas. Also, as in the above premixing device Ad, there is no need to provide multiple parallel flow paths, and the fuel gas flow path 7 can be simplified.

In the premixing device Af shown in Fig. 29, a premix flow passage forming member 4F is configured by using the first and second tubular parts 4b and 4c. An air inflow opening 40a is provided at the base end of the first tubular part 4b, and the inside of the first and second tubular parts 4b and 4c forms a premix flow passage 40. A fuel gas outlet 74a is provided as a gap opening to the premix flow passage 40 between the tip end of the first tubular part 4b and the base end of the second tubular part 4c. The fuel gas supplied to the pipe joint part 51 passes through a region 72 provided between the first and second tubular parts 4b and 4c and the housing member 5F and reaches the fuel gas outlet 74a.
The housing member 5F is provided with a pipe joint portion 51, which is provided with two parallel flow paths 71A, 71B, for example, similar to that shown in Fig. 4. Either one of the two fuel gas supply ports 70 (70a, 70b), which are openings of the parallel flow paths 71A, 71B, can be selectively blocked by a fuel gas flow path adjusting member 8.

In the present embodiment, negative pressure is generated near the fuel gas outlet 74a due to air flowing through the venturi-shaped premixing channel 40, and fuel gas flows out from the fuel gas outlet 74a into the premixing channel 40. Unlike the previously described embodiment, the blade portion 6 provided with the fuel gas outlet 74 is not used, but it is possible to appropriately generate a mixture of air and fuel gas. The premixing channel and the premixing channel-forming member in the present invention may be configured as in the present embodiment.

The present invention is not limited to the above-described embodiment. 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.

In the above-described embodiment, the fuel gas flow path adjustment member 8, 8A to 8E is indirectly attached to the premix flow path forming member 4, 4F via the housing member 5, 5F, but the present invention is not limited to this. For example, if the premix flow path forming member is provided with a pipe joint portion for connecting a gas pipe, the fuel gas flow path adjustment member may be attached to this portion, that is, the fuel gas flow path adjustment member may be directly attached to the premix flow path forming member.
There are no limitations on the specific shape, size, material, etc. of the fuel gas flow path adjusting member.
The fuel gas is not limited to natural gas and LP gas, and other types of fuel gas can also be applied to the present invention.
The combustion device according to the present invention is not limited to a hot water supply device, but may be used for other purposes such as heating, incineration, etc. Also, it is not limited to a type in which the combustion gas flows downward, but may be a type in which the fuel gas flows upward, for example.

A, Aa to Af: premixing device B; combustion device 3a, 3b; first and second gas type display units 4, 4F; premixing flow passage forming member 40; premixing flow passage 5, 5F; housing member 51; pipe joint portion 51a; cylindrical portion (of pipe joint portion)
51b Inner wall portion (of the pipe joint portion)
59 Screw hole 7 Fuel gas flow passage 70 Fuel gas supply port 71 Parallel flow passages 71A, 71B First and second parallel flow passages 74, 74a Fuel gas outlet port 8, 8A to 8E Fuel gas flow passage adjustment member 83 Sealing convex portion 9 Gas pipe

Claims (6)

a premixing flow passage forming member that forms a premixing flow passage for allowing air to flow from one end side to the other end side and for mixing the air with a fuel gas;
a fuel gas flow path having a fuel gas supply port for receiving a supply of the fuel gas from an outside and a fuel gas outlet opening into the premixing flow path, the fuel gas being supplied to the fuel gas supply port and being configured to guide the fuel gas to the fuel gas outlet;
A premixing device comprising:
the premixing flow passage forming member is directly or indirectly attached to the premixing flow passage forming member, and the fuel gas flow passage adjusting member is capable of blocking a part of the fuel gas flow passage,
an attachment manner of the fuel gas flow path adjusting member is changeable, and by changing the attachment manner, a position and/or an area where the fuel gas flow path adjusting member blocks the fuel gas flow path can be changed, thereby changing a flow path resistance of the fuel gas flow path ,
The fuel gas includes first and second predetermined fuel gases different in type,
an attachment mode of the fuel gas flow path adjusting member can be selectively set to either a first attachment mode in which the fuel gas flow path corresponds to the first fuel gas or a second attachment mode in which the fuel gas flow path corresponds to the second fuel gas;
The fuel cell further includes first and second gas type indicators indicating the first and second fuel gases, respectively.
a premixing device configured such that, when the fuel gas flow path adjustment member is set in the first installation mode, the second gas type indication portion is covered and hidden by the fuel gas flow path adjustment member and the first gas type indication portion is exposed, and, when the fuel gas flow path adjustment member is set in the second installation mode, the first gas type indication portion is covered and hidden by the fuel gas flow path adjustment member and the second gas type indication portion is exposed. a premixing flow passage forming member that forms a premixing flow passage for allowing air to flow from one end side to the other end side and for mixing the air with a fuel gas;
a fuel gas flow path having a fuel gas supply port for receiving a supply of the fuel gas from an outside and a fuel gas outlet opening into the premixing flow path, the fuel gas being supplied to the fuel gas supply port and being configured to guide the fuel gas to the fuel gas outlet;
A premixing device comprising:
the premixing flow passage forming member is directly or indirectly attached to the premixing flow passage forming member, and the fuel gas flow passage adjusting member is capable of blocking a part of the fuel gas flow passage,
an attachment manner of the fuel gas flow path adjusting member is changeable, and by changing the attachment manner, a position and/or an area where the fuel gas flow path adjusting member blocks the fuel gas flow path can be changed, thereby changing a flow path resistance of the fuel gas flow path,
The fuel gas supply system further includes a pipe joint having a cylindrical portion with an open tip for connecting a gas pipe for supplying the fuel gas,
the fuel gas supply port is provided in an inner wall portion of the cylindrical portion,
the fuel gas flow path adjusting member is inserted into the cylindrical portion from a tip opening thereof and attached to the inner wall portion by a fastening member. a premixing flow passage forming member that forms a premixing flow passage for allowing air to flow from one end side to the other end side and for mixing the air with a fuel gas;
a fuel gas flow path having a fuel gas supply port for receiving a supply of the fuel gas from an outside and a fuel gas outlet opening into the premixing flow path, the fuel gas being supplied to the fuel gas supply port and being configured to guide the fuel gas to the fuel gas outlet;
A premixing device comprising:
the premixing flow passage forming member is directly or indirectly attached to the premixing flow passage forming member, and the fuel gas flow passage adjusting member is capable of blocking a part of the fuel gas flow passage,
an attachment manner of the fuel gas flow path adjusting member is changeable, and by changing the attachment manner, a position and/or an area where the fuel gas flow path adjusting member blocks the fuel gas flow path can be changed, thereby changing a flow path resistance of the fuel gas flow path,
a portion of the fuel gas flow path adjacent to the fuel gas supply port is divided into a plurality of parallel flow paths, and a plurality of fuel gas supply ports corresponding to the plurality of parallel flow paths are provided as the fuel gas supply port,
a position where the fuel gas flow path adjusting member blocks the plurality of fuel gas supply ports and/or a number of the fuel gas supply ports are changeable;
the plurality of parallel flow paths include first and second parallel flow paths having flow path areas different from each other, and the plurality of fuel gas supply ports include first and second fuel gas supply ports corresponding to the first and second flow paths,
a fuel gas flow path adjusting member that is capable of selectively closing one of the first and second fuel gas supply ports ; A premixing device according to any one of claims 1 to 3 ,
a premixing device configured to cause the fuel gas to flow out from the fuel gas outlet into the premixing channel by the action of negative pressure generated by airflow in the premixing channel . 4. The premixing device of claim 3 ,
the first and second parallel flow paths have portions closer to the first and second fuel gas supply ports that are the same in shape and size;
the fuel gas flow path adjusting member has a sealing convex portion that can be fitted into a portion close to the first and second fuel gas supply ports . A combustion system comprising a premixing device according to any one of claims 1 to 5.

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