JP7560109B2 - Gas distribution units and water heaters - Google Patents

Description

The present invention relates to a gas distribution unit that is provided in a water heater to distribute and supply fuel gas to multiple burners, and to a water heater equipped with the gas distribution unit.

The water heater comprises a combustion device with a burner and a heat exchanger within a housing, and the water passing through the heat exchanger is heated by the combustion exhaust of the burner, which ignites and burns a mixture of fuel gas and combustion air, to produce hot water.
A plurality of flat burners are arranged in the thickness direction, and a gas distribution unit is provided on the upstream side. As disclosed in Patent Document 1, this gas distribution unit has a plurality of branch flow paths that branch the fuel gas supplied from the upstream side, and a passage part through which the fuel gas is introduced is provided on the upstream side of each branch flow path, and a distribution space in which a plurality of nozzles corresponding to each burner are partitioned is provided on the downstream side. Each passage part can be opened and closed by an electromagnetic valve, and the number of burners to be burned can be adjusted by selecting the branch flow path through which the fuel gas is supplied by controlling the electromagnetic valve. The gas distribution unit is formed in a plate shape extending in the left-right direction, and is attached to the front surface of the casing that forms the combustion chamber.

JP 2015-197273 A

In recent years, as devices have become lighter and more compact, there has been a trend towards limiting the size of gas distribution units. To supply the necessary fuel gas to each nozzle, it is desirable to make the passage larger (wider flow area), but there are cases where the passage cannot be made larger due to layout restrictions. As a result, the fuel gas supplied from the passage to the distribution space tends to flow unevenly to the nozzles closer to the passage, which can lead to a deterioration in combustion performance.

The present invention aims to provide a gas distribution unit and a water heater that can supply fuel gas evenly and stably to the distribution space that forms the branch flow path.

In order to achieve the above object, a first aspect of the present invention is a gas distribution unit that is assembled to a combustion device accommodating a plurality of burners, and includes a plurality of branch flow paths that distribute and supply fuel gas to the burners, each of the branch flow paths including a passage portion into which the fuel gas is introduced and a distribution space that communicates with a downstream end of the passage portion, and a plurality of nozzles that eject fuel gas to each of the burners are arranged side by side in a predetermined linear direction in the distribution space,
In at least one of the branch flow paths, the passage portion branches into two, each of which is connected to the distribution space, one of the branched branch passage portions is connected to the distribution space in a direction perpendicular to the linear direction in which the nozzles are arranged side by side, and the other branch passage portion is connected to the distribution space in a direction parallel to the linear direction,
The present invention is characterized in that an extension line of the center of the one branch passage portion is connected to the distribution space at a position offset from the center of the nozzle .
The term "orthogonal direction" includes a strict orthogonal direction as well as a small margin of error. The term "parallel direction" includes a strict parallel direction as well as a small margin of error.
In another aspect of the first invention, in the above configuration, the nozzles are arranged in parallel in two rows,
The nozzles may be arranged such that extension lines of the centers of the branch passage portions intersect within an area surrounded by four of the nozzles that are adjacent to each other in the linear direction and the orthogonal direction.
Another aspect of the first invention is characterized in that in the above-mentioned configuration, a mounting portion for mounting to the combustion device is provided between the two branch passage portions.
In order to achieve the above-mentioned object, the second invention of the present invention is a water heater characterized in that a gas distribution unit described in any of the first inventions is assembled to a combustion device containing a plurality of burners.

According to the present invention, the passage portion in one branch flow path branches into two, each of which is connected to a distribution space, and one of the branched branch passage portions is connected to the distribution space in a direction perpendicular to the linear direction in which the nozzles are arranged side by side, so that the fuel gas supplied from the passage portion to the distribution space is less likely to flow biased toward the nozzle closer to the passage portion. Therefore, the fuel gas can be supplied evenly and stably to the distribution space forming the branch flow path. In addition, the other branch passage portion is connected to the distribution space in a direction parallel to the linear direction in which the nozzles are arranged side by side, so that the fuel gas flowing from the two branch passage portions can collide with each other, thereby distributing the fuel gas better.
In addition, since an extension line of the center of one of the branch passage portions is connected to the distribution space at a position offset from the center of the nozzle, it is possible to effectively prevent the fuel gas from being biased toward the nozzle closer to that passage portion.
According to another embodiment in which the nozzles are arranged in parallel in two rows and the extension lines of the centers of the two branch passage portions intersect within an area surrounded by four nozzles, the required flow rate can be ensured and the fuel gases flowing in from the two branch passage portions can be caused to collide with each other, thereby achieving better distribution of the fuel gas.
According to another aspect in which an attachment portion to the combustion device is provided between the two branch passage portions, even when two branch passage portions are provided, the combustion device can be fixed in close contact with the combustion device, thereby improving sealing performance.

FIG. 2 is a front view of the water heater with the front cover removed. FIG. 2 is an exploded front perspective view of the gas distribution unit; FIG. 2 is a rear perspective view of the gas distribution unit. FIG. FIG. 4 is an enlarged view of a second distribution recess portion.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory diagram showing an example of a water heater, showing the front view with the front cover removed.
The water heater 1 has a combustion device 3, a heat exchanger 4, and an exhaust section 5 installed in a rectangular box-shaped housing 2. A gas distribution unit 6 is attached to the front of the combustion device 3 for distributing and supplying fuel gas to a burner unit (not shown) in the combustion device 3. The burner unit is made up of multiple light and dark burners that are flat in the left-right direction and arranged in the left-right direction.
An intake fan 7 for supplying combustion air is attached to the underside of the combustion device 3, and a controller 8 equipped with a control circuit board is disposed in front of the intake fan 7. Air intakes 9, 9 ... are formed in the back plate of the housing 2. An exhaust pipe 10 is formed in the exhaust section 5, penetrating the top plate of the housing 2 and protruding upward.

A water supply pipe 11 is connected to the inlet end of the heat transfer pipe of the heat exchanger 4, and a hot water outlet pipe 12 is connected to the outlet end of the heat transfer pipe. A water inlet 13 to which an external water pipe is connected, and a hot water outlet 14 to which an external pipe to a hot water tap is connected are provided on the underside of the housing 2. The upstream end of the water supply pipe 11 is connected to the water inlet 13, and the downstream end of the hot water outlet pipe 12 is connected to the hot water outlet 14.
In addition, a gas inlet 15 to which an external gas pipe is connected is provided on the bottom surface of the housing 2. The gas inlet 15 is connected to the gas distribution unit 6 within the housing 2 via a gas proportional valve unit 16 that includes a proportional valve and a master solenoid valve on the upstream side of the proportional valve.
The gas distribution unit 6 is attached to the front surface of the inner case 17 of the combustion device 3, which houses the burner unit, in such a manner as to close the opening at the lower front surface of the inner case 17. A frame rod 18 and a discharge electrode 19 are inserted and connected to the front surface of the inner case 17 above the gas distribution unit 6.

2 and 3, the gas distribution unit 6 has a horizontally elongated flat shape formed by a rear main body 20 and a front cover 21 that is screwed to the main body 20 from the front. A seal member 22 is interposed between the main body 20 and the cover 21.
In the gas distribution unit 6, a gas inlet 23, and a first branch flow path 24 and a second branch flow path 25 branching from the gas inlet 23 are formed by the main body 20 and the cover 21. The first branch flow path 24 has a first distribution space 24a extending in the left-right direction above the gas distribution unit 6, and a first passage portion 24b extending downward in communication with the first distribution space 24a. The second branch flow path 25 also has a second distribution space 25a extending in the left-right direction on the left side of the first distribution space 24a, and two second passage portions 25b1, 25b2 extending downward in communication with the second distribution space 25a.
A cylindrical gas inlet 26 protrudes rearward from the lower left side of the rear surface of the aluminum die-cast main body 20. A gas outlet portion (not shown) provided at the upper end of the gas proportional valve unit 16 is connected to the gas inlet 26 from the rear.

As shown in FIG. 4, the lower front surface of the main body 20 is provided with an inlet recess 27 that communicates with the gas inlet 26 to form the gas inlet 23. The upper front surface of the main body 20 is provided with a first distribution recess 28 that extends in the left-right direction to form the first distribution space 24a, and a second distribution recess 29 that also extends in the left-right direction to form the second distribution space 25a. The first and second distribution recesses 28, 29 are horizontally elongated rectangular shapes that extend in the left-right direction, and the first distribution recess 28 is longer in the left-right direction than the second distribution recess 29. At the bottoms of the first and second distribution recesses 28, 29, a plurality of nozzles 30, 30... that are tapered toward the rear side are arranged in parallel at equal intervals in the left-right linear direction. The nozzles 30, 30... are arranged in two parallel rows, one above the other. A pair of upper and lower nozzles 30, 30 correspond to the lean gas supply holes and rich gas supply holes of each of the rich and lean burners that make up the first and second burner groups. There are eight pairs of nozzles 30 for the first distribution recesses 28 and four for the second distribution recesses 29, with the first distribution recesses 28 being more numerous.

Meanwhile, a first inlet 31 and a second inlet 32 penetrating from front to back are formed on the upper left and right sides of the inlet recess 27, and each of them communicates with the inlet recess 27. On the back surface of the main body 20, the first and second inlets 31, 32 are provided with solenoid valves 33, 33 (FIG. 3) that open and close the communication portion with the inlet recess 27.
A bent first passage recess 34 is formed continuously at the first inlet 31, extending upward, then bending to the right and communicating over the entire length with the lower part of the first distribution recess 28. The first passage recess 34 forms the first passage portion 24b.
The second inlet 32 is continuously formed with second passage recesses 35, 36 which branch into two and are each connected to the second distribution recess 29. The second passage recess 35 is formed in a semicircular shape that branches to the right and curves upward, and is connected perpendicularly to the lower left end of the second distribution recess 29. The second passage recess 36 is formed in an inverted L shape that extends upward and then bends to the right, and is connected perpendicularly to the left end of the second distribution recess 29. The second passage recess 35 forms the second passage portion 25b1, and the second passage recess 36 forms the second passage portion 25b2.

5, the second passage recess 35 is connected to the lower end of the second distribution recess 29 such that an extension line L1 passing through the center of the second passage recess 35 (second passage portion 25b1) passes between the four nozzles 30, 30... (hereinafter, when distinguishing between them, they will be written as "30L, 30L") located on the left side of the second distribution recess 29. In other words, the extension line L1 is deviated in the left-right direction from the center O of each nozzle 30L when viewed from the front.
Further, the second passage recess 36 is connected to the left end of the second distribution recess 29 such that an extension line L2 passing through the center of the second passage recess 36 (second passage portion 25b2) passes between the upper and lower nozzles 30L, 30L in the second distribution recess 29. In other words, the extension line L2 is vertically deviated from the center O of each nozzle 30L in a front view.
Therefore, an extension line L1 of the second passage portion 25b1 and an extension line L2 of the second passage portion 25b2 intersect at an intersection P in the area surrounded by the four nozzles 30L in the second distribution recess 29.

Screw holes 37, 37... are formed around the first and second distribution recesses 28, 29, the first passage recess 34, the second passage recess 35, 36, and the inlet recess 27 for screwing the cover 21. In addition, outside the area surrounded by the screw holes 37, the main body 20 is formed with mounting holes 38, 38... for screwing to the inner case 17. This mounting hole 38 is also formed between the second passage recesses 35, 36 (labeled "38A" to distinguish between them).

The cover 21 is a metal plate that covers from the front an area including the first and second distribution recesses 28, 29, the first passage recess 34, the second passage recesses 35, 36, and the inlet recess 27. The cover 21 is formed with a first bulge 40 that spans the first distribution recess 28 and the first passage recess 34. The first bulge 40, the first distribution recess 28, and the first passage recess 34 form the first branch flow path 24.
Further, a second bulge 41 is formed in the cover 21, spanning the second distribution recess 29 and the second passage recesses 35, 36. The second bulge 41 also branches in accordance with the second passage recesses 35, 36. The second bulge 41, the second distribution recess 29, and the second passage recesses 35, 36 form a second branch flow path 25.
A third bulge 42 is formed below both the bulges 40, 41 and located in front of the inlet recess 27. The third bulge 42 and the inlet recess 27 form the gas inlet 23.
Around each of the bulging portions 40 to 42 in the cover 21, through-holes 43, 43... are formed to correspond to each of the screw holes 37 in the main body 20 for screwing the cover 21. In addition, between the branching portions in the second bulging portion 41 that correspond to the second passage portions 25b1, 25b2, a through-hole 44 that corresponds to the mounting hole 38 in the main body 20 is formed.

The seal body 22 is connected in a net-like manner around the first and second distribution recesses 28, 29, the first passage recess 34, the second passage recesses 35, 36, and the inlet recess 27 of the main body 20, and between the first distribution recess 28 and the first passage recess 34, and the second distribution recess 29 and the second passage recesses 35, 36, etc., and is interposed between the main body 20 and the cover body 21. Small holes 45, 45... are formed in the main body 20 at positions corresponding to the screw holes 37.
Therefore, by positioning the seal body 22 on the front surface of the main body 20 to which the solenoid valves 33, 33 are attached, and then screwing in the screws 46, 46... (FIG. 1) at the positions of the through holes 43 of the lid body 21 with the seal body 22 placed on the front surface of the main body 20, the lid body 21 is screwed to the main body 20 via the seal body 22. Then, by setting the main body 20 on the front surface of the inner case 17, connecting the gas proportional valve unit 16 to the gas inlet 26, and fixing it in place with the screws 47, 47... (FIG. 1) at the positions of the mounting holes 38, 38A, the assembly of the gas distribution unit 6 is completed.

In the water heater 1 configured as described above, when the hot water tap connected to the piping of the hot water outlet 14 is opened to allow water to flow into the appliance, the controller 8 detects this and opens the master solenoid valve of the gas proportional valve unit 16, and controls the proportional valve to a predetermined opening degree for ignition. The controller 8 also opens the solenoid valves 33, 33 of the corresponding first and second branch flow paths 24, 25, and operates the air supply fan 7 to supply air for combustion. Thus, fuel gas is supplied to the gas distribution unit 6 via the gas proportional valve unit 16.
At this time, when the solenoid valve 33 in the first branch flow passage 24 opens, the fuel gas that has entered the gas inlet section 23 from the gas inlet 26 rises along the first passage section 24b, enters the first distribution space 24a, diffuses, and is supplied to each concentrated/light burner from each nozzle 30.

On the other hand, when the solenoid valve 33 opens in the second branch flow passage 25, the fuel gas that enters the gas inlet 23 from the gas inlet 26 branches into the second passages 25b1 and 25b2, and then enters the second distribution space 25a from the lower and left sides. Then, as shown by the dotted arrows in FIG. 5, the upward fuel gas that enters the second distribution space 25a from the second passage 25b1 and the sideways fuel gas that enters the second distribution space 25a from the second passage 25b2 collide near the intersection P. Therefore, the fuel gas diffuses into the second distribution space 25a and flows evenly to each nozzle 30, suppressing bias toward the light and dark burners.

Then, when the igniter is operated by the controller 8 and the discharge electrode 19 continuously discharges, the mixture sprayed from the flame hole of each light and dark burner is burned. The combustion exhaust of the burner unit is heat exchanged with the water passing through the heat transfer tube of the heat exchanger 4, and hot water of the set temperature is discharged from the hot water outlet tube 12. The controller 8 adjusts the opening of the proportional valve according to the required combustion amount, adjusts the supply amount of fuel gas from the gas proportional valve unit 16, and continuously changes the rotation speed of the air supply fan 7 to maintain a predetermined air-fuel ratio. In addition, the controller 8 selects the first and second burner groups and controls the number of combustions in stages by controlling the opening and closing of the solenoid valves 33, 33 of the gas distribution unit 6 according to the required combustion amount. In the second branch flow path 25 corresponding to the second burner group, the fuel gas flows evenly to each nozzle 30 as described above, so the combustion performance of the second burner group can be maintained.

In the gas distribution unit 6 and the water heater 1 of the above-described configuration, in the second branch flow passage 25, the second passage portion 25b1 is connected to the second distribution space 25a in a direction perpendicular to the linear direction in which the nozzles 30 are arranged side by side.
With this configuration, the fuel gas supplied from the second passage portion 25b1 to the second distribution space 25a is less likely to flow biased toward the nozzle 30 closer to the second passage portion 25b1. Therefore, the fuel gas can be supplied evenly and stably to the second distribution space 25a that forms the second branch flow path 25.
In particular, the extension line L1 of the center of the second passage portion 25b1 is connected to the second distribution space 25a at a position away from the center O of the nozzle 30L. Therefore, it is possible to effectively prevent the fuel gas from being biased toward the nozzle 30L close to the second passage portion 25b1.

The nozzles 30 are arranged in two rows in parallel, and the second passage portions 25b1 and 25b2 are branched into two and each is connected to the second distribution space 25a. One of the branched second passage portions 25b1 (branched passage portion) is connected to the second distribution space 25a in a direction perpendicular to the left-right direction in which the nozzles 30 are arranged, and the other second passage portion 25b2 (branched passage portion) is connected to the second distribution space 25a in parallel to the left-right direction in which the nozzles 30 are arranged, and the extension lines L1 and L2 of the centers of the second passage portions 25b1 and 25b2 intersect at an intersection P within a region surrounded by four nozzles 30L adjacent to each other in the up-down and left-right directions.
Therefore, a necessary flow rate can be ensured, and the fuel gases flowing in from the two second passage portions 25b1, 25b2 can be caused to collide with each other, thereby achieving better distribution of the fuel gas.
Between the two second passage portions 25b1, 25b2, there is provided a mounting hole 38A (mounting portion) for mounting to the inner case 17 of the combustion device 3. Therefore, even if two second passage portions 25b1, 25b2 are provided, they can be fixed in close contact with the inner case 17, and the sealing performance can be improved.

The following describes a modified example.
In the gas distribution unit of the above embodiment, two passages are connected to the distribution space of the left branch flow path, but depending on the structure of the gas distribution unit, two passages may be connected to the distribution space of the right branch flow path. Two passages may also be connected to each of the left and right branch flow paths.
The gas distribution unit may also include three or more branch passages. In this case, one or more branch passages connecting two passages may be provided.
However, the number of passages is not limited to two, and only one passage may be provided that is connected in a direction perpendicular to the linear direction in which the nozzles are arranged side by side. A mode in which the extension line of the center of the passage is not offset from the center of the nozzle may also be adopted. The number of nozzle rows is also not limited to two, and may be one row.
The configuration of the water heater itself is not limited to the above-mentioned form. For example, the present invention can be applied to a type that includes a secondary heat exchanger to recover latent heat, or a type that includes a bath side circuit and a heating side circuit.

1. Water heater, 2. Housing, 3. Combustion device, 4. Heat exchanger, 5. Exhaust section, 6. Gas distribution unit, 8. Controller, 11. Water supply pipe, 12. Hot water outlet pipe, 13. Water inlet, 14. Hot water outlet, 15. Gas inlet, 16. Gas supply unit, 17. Inner case, 20. Main body, 21. Lid, 23. Gas introduction section, 24. First branch flow path, 24a. First distribution space, 24b. First passage section, 25.・Second branch flow path, 25a...Second distribution space, 25b1, 25b2...Second passage portion, 26...Gas inlet, 27...Inlet recess, 28...First distribution recess, 29...Second distribution recess, 30...Nozzle, 34...First passage recess, 35, 36...Second passage recess, 38, 38A...Mounting hole, L1...Extension line of the center of the second passage portion 25b1, L2...Extension line of the center of the second passage portion 25b2, P...Intersection of the extension lines L1 and L2.

Claims (4)

A gas distribution unit which is assembled to a combustion device accommodating a plurality of burners and includes a plurality of branch flow paths which distribute and supply a fuel gas to the burners, each of the branch flow paths including a passage portion into which the fuel gas is introduced and a distribution space which communicates with a downstream end of the passage portion, and in the distribution space, a plurality of nozzles which spray the fuel gas to each of the burners are arranged side by side in a predetermined linear direction,
In at least one of the branch flow paths, the passage portion branches into two, each of which is connected to the distribution space, one of the branched branch passage portions is connected to the distribution space in a direction perpendicular to the linear direction in which the nozzles are arranged side by side, and the other branch passage portion is connected to the distribution space in a direction parallel to the linear direction,
a center extension line of said one branch passage portion is connected to said distribution space at a position offset from the center of said nozzle ; The nozzles are arranged in two rows in parallel,
2. The gas distribution unit according to claim 1 , wherein extension lines of the centers of the branch passage portions intersect within an area surrounded by four of the nozzles adjacent to each other in the linear direction and the orthogonal direction. 3. The gas distribution unit according to claim 1, further comprising an attachment portion for attaching to the combustion device, the attachment portion being provided between the two branch passage portions. A water heater comprising a combustion device accommodating a plurality of burners and a gas distribution unit according to any one of claims 1 to 3 attached thereto.

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