JP7426080B2 - Gas distribution unit and water heater - Google Patents

Description

The present invention relates to a gas distribution unit provided for distributing and supplying fuel gas to a plurality of burners in a water heater, and a water heater equipped with the gas distribution unit.

The water heater includes a combustion device equipped with a burner and a heat exchanger in a housing, and combustion exhaust from the burner ignites and burns a mixture of fuel gas and combustion air, which passes through the heat exchanger. Heat the water and make it hot.
A plurality of burners are arranged in the thickness direction, and a gas distribution unit is provided on the upstream side. As disclosed in Patent Documents 1 and 2, this gas distribution unit has a main flow path to which fuel gas is supplied from the upstream side, and a plurality of branch flow paths branching from the main flow path, and each branch flow path A plurality of gas nozzles are provided at the downstream end of the burner, corresponding to each burner. The upstream end of each branch channel can be opened and closed by a solenoid valve, and by controlling the solenoid valve and selecting the branch channel to which fuel gas is supplied, the number of burners to be burned can be adjusted. ing.
The main body of such a gas distribution unit is integrally molded by die casting, which is small and lightweight and can reduce manufacturing costs. In particular, the main flow path is formed in the left-right direction in consideration of space saving within the housing.

Japanese Patent Application Publication No. 2015-197273 Patent No. 5921584

In the conventional gas distribution unit described above, by forming the main flow path in the left-right direction, the length of the main flow path becomes short, and the supply pressure of fuel gas cannot be sufficiently relaxed. For this reason, a large amount of fuel gas may be concentrated and supplied to the branch channel near the gas inlet to the main channel, or conversely, it may pass through the branch channel near the gas inlet and be supplied to the branch channel far from the gas inlet. Fuel gas may be supplied in a concentrated manner. Therefore, fuel gas may not be uniformly supplied to each burner in use.

Therefore, an object of the present invention is to provide a gas distribution unit and a water heater that can uniformly supply fuel gas to each burner.

In order to achieve the above object, a first aspect of the present invention is a gas distribution unit that is assembled into a combustion device that accommodates a plurality of burners and distributes and supplies fuel gas to the burners,
casing and
a gas inlet formed in the casing;
a main channel formed in the casing, communicating with the gas inlet and extending in the left-right direction;
a plurality of branch channels formed within the casing, branching from the main channel and extending upward;
a plurality of electromagnetic valves each provided in the casing at the upstream end of each branch flow path and capable of opening and closing each upstream end;
A plurality of nozzles each provided in the casing at the downstream end of each branch flow path and supplying fuel gas to a predetermined number of burners,
The casing forming the upstream end of each branch flow path is formed with a protrusion that projects downward into the main flow path, and the lower surface of each protrusion has a communication port that communicates the upstream end with the main flow path. While each is formed,
The communication port in one or more protrusions located on the upstream side of the main flow path is characterized in that it opens toward the downstream side of the main flow path .
Another aspect of the first invention is characterized in that, in the above configuration, the protrusion located on the upstream side is formed in a semicircular shape when viewed from the front.
Another aspect of the first invention is characterized in that, in the above configuration, the amount of protrusion of the protrusion located on the upstream side into the main flow path is more than half of the vertical width of the main flow path.
In order to achieve the above object, a second invention of the present invention provides a water heater in which the gas distribution unit according to any one of the first inventions is assembled into a combustion device that accommodates a plurality of burners. It is characterized by being

According to the present invention, it is possible to prevent the fuel gas immediately after entering the main flow path from the gas introduction port from being forcefully supplied into the upstream branch flow path. Therefore, an appropriate amount of fuel gas can be supplied to the branch flow path on the downstream side, and fuel gas can be uniformly supplied to each burner. Furthermore, since the protrusion protrudes into the main flow path, the direction of the communication port can be easily set.
In addition , since the communication port at the protrusion located on the upstream side of the main flow path opens toward the downstream side of the main flow path, the force of the fuel gas flowing from the main flow path to the protrusion can be more effectively reduced. be able to.
According to another aspect of the present invention, in addition to the above effects, the protrusion located on the upstream side is formed in a semicircular shape when viewed from the front, so that the resistance to the flow of fuel gas is prevented from becoming excessively high. This can be prevented and a smooth flow can be ensured.
According to another aspect of the present invention, in addition to the above effects, the amount of protrusion of the protrusion into the main flow path is more than half of the vertical width of the main flow path, so that the fuel gas near the gas inlet is The flow can be appropriately attenuated. Therefore, it is possible to promote the circulation of fuel gas and supply an appropriate amount of fuel gas to the upstream branch flow path, and it is also possible to supply a certain amount or more of fuel gas to the downstream branch flow path. .

FIG. 3 is a perspective view of the water heater with the front cover removed. FIG. 3 is a front view of the water heater with the front cover removed. FIG. 3 is a front view showing a portion of the gas distribution unit and the gas proportional valve unit. FIG. 2 is a side view of a portion of a gas distribution unit and a gas proportional valve unit. FIG. 3 is an exploded front perspective view of the gas distribution unit. FIG. 3 is an exploded perspective view of the gas distribution unit from the rear. FIG. 3 is a front view of the main body. FIG. 4 is an enlarged cross-sectional view taken along the line AA in FIG. 3. FIG. 4 is an enlarged sectional view taken along the line BB in FIG. 3; It is a longitudinal cross-sectional view of the 4th valve chamber part in a main body. FIG. 4 is an enlarged sectional view taken along the line CC in FIG. 3. FIG. 4 is an enlarged cross-sectional view taken along line DD in FIG. 3;

Embodiments of the present invention will be described below based on the drawings.
(Description of water heater)
1 and 2 are explanatory diagrams showing an example of a water heater. FIG. 1 shows a perspective view with a front cover removed, and FIG. 2 shows a front view.
The water heater 1 has a combustion device 3 and a heat exchanger 4 installed above the combustion device 3 in a square box-shaped casing 2. A gas distribution unit 5 for distributing and supplying fuel gas to burner units (not shown) in the combustion device 3 is assembled on the front surface of the combustion device 3 . An air supply fan 6 that supplies combustion air is attached to the lower surface of the combustion device 3. The heat exchanger 4 includes a lower primary heat exchanger 4A that recovers sensible heat from the combustion exhaust of the burner unit, and an upper secondary heat exchanger 4B that recovers latent heat. The interiors of the combustion device 3 and the primary and secondary heat exchangers 4A and 4B are partitioned into a bath side and a hot water supply side, respectively. The combustion exhaust gas that has passed through the secondary heat exchanger 4B can be discharged to the outside from an exhaust port 7 provided on the front surface of the secondary heat exchanger 4B.

In the primary heat exchanger 4A, the inlet end of the heat exchanger tube of the hot water supply side primary heat exchanger is connected to the outlet end of the heat absorption tube of the hot water supply side secondary heat exchanger, and the outlet end of the heat exchanger tube is connected to the outlet end of the heat absorption tube of the hot water supply side secondary heat exchanger. It is connected to the hot water outlet pipe 8. In the secondary heat exchanger 4B, the inlet end of the heat absorption pipe of the hot water supply side secondary heat exchanger is connected to the water supply pipe 9. In the primary heat exchanger 4A, the inlet end of the heat exchanger tube of the bath side primary heat exchanger is connected to the outlet end of the heat absorption tube of the bath side secondary heat exchanger, and the outlet end of the heat exchanger tube is connected to the outlet end of the heat absorption tube of the bath side secondary heat exchanger. It is connected to the outgoing pipe 10. In the secondary heat exchanger 4B, the inlet end of the heat absorption pipe of the bath-side secondary heat exchanger is connected to the return pipe 11.
The lower surface of the housing 2 has a gas inlet 12 to which an external gas pipe is connected, a water inlet 13 to which a water pipe is connected, a hot water outlet 14 to which an external pipe to a hot water tap is connected, and an external bathtub. An outgoing port 15 and a return port 16 are provided which are connected to. The gas inlet 12 is connected in the housing 2 to the gas distribution unit 5 via a gas proportional valve unit 17 comprising a proportional valve 18 and an original solenoid valve 19 upstream thereof. The water inlet 13 is connected to the water supply pipe 9, and the hot water outlet 14 is connected to the hot water outlet pipe 8. The outgoing port 15 is connected to the outgoing pipe 10 and the return port 16 is connected to the return pipe 11. A controller (not shown) including a control circuit board is arranged in front of the gas proportional valve unit 17.

(Description of gas distribution unit)
The gas distribution unit 5 is assembled to the front surface of the inner case 20 so as to close the opening at the lower front surface of the inner case 20 of the combustion device 3 that accommodates the burner unit. As shown in FIGS. 3 to 6, this gas distribution unit 5 has a horizontally long flat casing 25 formed by a rear main body 26 and a front lid 27. 27, a seal body 28 is interposed. A cylindrical gas inlet 29 is provided on the lower right side of the rear surface of the main body 26 and projects backward, and a gas outlet 21 provided at the upper end of the gas proportional valve unit 17 is connected to this gas inlet 29 from the rear. be done.
The burner unit is formed by arranging a plurality of horizontally flat concentration burners in the left-right direction, and inside the gas distribution unit 5, the fuel gas is supplied from the gas proportional valve unit 17, which extends in the left-right direction at the lower part of the casing 25. and four first to fourth branch channels 31A that branch upward from the main channel 30 and distribute fuel gas to a predetermined number of concentration burners (first to fourth burner groups). 31D is formed. Here, the first branch flow path 31A on the right end is used for bathing, and the three second to fourth branch flow paths 31B to 31D on the left side are used for hot water supply. The gas introduction port 29 is formed at the right end of the main flow path 30.

The main body 26 is in the form of a plate made of aluminum die-casting, and has holes extending in the left-right direction at positions corresponding to the first to fourth branch channels 31A to 31D on the upper side of the inner region, respectively, as shown in FIGS. 7 and 8. A pair of upper and lower groove-shaped first to fourth nozzle portions 32A to 32D are provided. The first to fourth nozzle parts 32A to 32D have a set of upper and lower nozzles corresponding to the light gas supply holes and rich gas supply holes of each of the concentrated burners constituting the first to fourth burner groups, and have a shape that tapers toward the rear side. A plurality of nozzles 33, 33 that are formed to protrude are arranged side by side in the left-right direction. Regarding the number of pairs of nozzles 33, 33, the second nozzle section 32B has the largest number, followed by the first and fourth nozzle sections 32A, 32D, and the third nozzle section 32C has the smallest number.

In addition, first to fourth vertical groove portions 34A to 34D extending in the vertical direction are provided below the first to fourth nozzle portions 32A to 32D at positions corresponding to the first to fourth branch channels 31A to 31D, respectively. It is being As shown in FIG. 9, first to fourth valve chambers 35A to 35D each having a cylindrical shape with a bottom and opening rearward are formed below the first to fourth longitudinal grooves 34A to 34D. In the first to fourth valve chambers 35A to 35D, electromagnetic valves 36, 36, . . . are assembled from the rear with the valve body 37, which is biased to project forward, facing forward. In front of the first to fourth valve chambers 35A to 35D, the main body 26 is formed with first to fourth gas inlets 38A to 38D, which communicate with the first to fourth valve chambers 35A to 35D, respectively. A valve seat 39 that is closed from the rear by the valve body 37 of the electromagnetic valve 36 is formed on the back surface of the first to fourth gas inlets 38A to 38D. Of the first to fourth gas inlets 38A to 38D, the second gas inlet 38B has the largest diameter, followed by the first and fourth gas inlets 38A and 38D, and the third gas inlet 38C has the smallest diameter.

A recess 40 extending in the left-right direction is formed below the first to fourth longitudinal grooves 34A to 34D at a position corresponding to the main flow path 30. The recess 40 is formed deeper toward the rear than the first to fourth longitudinal grooves 34A to 34D, and has a gas introduction port 29 formed at the right end thereof to protrude rearward.
The upper inner surface of the recess 40 is formed at a position that overlaps the first to fourth valve chambers 35A to 35D in the vertical direction, so that approximately the lower half of the first to fourth valve chambers 35A to 35D is connected to the inner surface of the recess 40. It protrudes downward from the upper inner surface. As a result, first to fourth upper protrusions 41A to 41D having semicircular shapes in front view are formed on the upper inner surface of the recess 40. Here, among the first to fourth valve chambers 35A to 35D, the two first and second valve chambers 35A and 35B on the upstream side (right side) near the gas inlet 29 are the third and fourth valve chambers 35C. , 35D, and protrudes more than half the vertical width of the recess 40.

As shown in FIG. First to fourth communication ports 43A to 43D are formed to communicate the fourth valve chambers 35A to 35D with the recess 40. In the first and second valve chambers 35A and 35B, the first and second communication ports 43A and 43B are formed on the left side of the first and second lower wall portions 42A and 42B, respectively, and sandwich the center in the left-right direction. It opens toward the opposite side (downstream side) of the gas inlet 29. The third and fourth communication ports 43C and 43D open downward at the center in the left-right direction of the third and fourth lower wall portions 42C and 42D.
In addition, on the inner surface of the lower side of the recess 40, at positions corresponding between the first to fourth upper protrusions 41A to 41D in the left-right direction, lower protrusions 44, 44, which protrude upward in an arcuate shape in front view. is formed.

As a result, the fuel gas introduced from the gas inlet 29 and flowing to the left inside the recess 40 is transferred to the first and second valve chambers 35A and 35B, as shown by dotted line arrows in FIG. After going around below the first and second lower wall parts 42A and 42B of the second upper protruding parts 41A and 41B, make a U turn upward and connect the first and second communication ports 43A and 43B respectively. It will flow into the valve chambers 35A and 35B. In particular, when it passes through the first upper protrusion 41A, it comes into contact with the lower protrusion 44 and is effectively guided upward.
On the other hand, in the two third and fourth valve chambers 35C and 35D on the downstream side (left side) far from the gas inlet 29, the fuel gas that has passed through the first and second valve chambers 35A and 35B is transferred to the third and fourth valve chambers 35C and 35D. The liquid changes direction upward from directly below the upper protrusions 41C and 41D and flows from the third and fourth communication ports 43C and 43D to the third and fourth valve chambers 35C and 35D, respectively.

The main body 26 has a cylindrical gas inlet 29 and the first to fourth valve chambers 35A to 35D formed in the front and back direction, so it can be molded using only front and rear split molds. can be done. Further, in the mold, a plurality of inlets are arranged along one of the upper edge and a lower edge of the main body 26 which are straight and parallel to each other, and a plurality of outlets are arranged in parallel along the other side. You can pour hot water (molten aluminum alloy, etc.) through the mouth.
Therefore, the flow direction of the hot water is aligned in one direction, improving the flowability of the hot water inside the cavity and suppressing the occurrence of "stains".
On the other hand, the first to fourth lower wall portions 42A to 42D forming the first to fourth valve chambers 35A to 35D are formed in a tapered shape whose diameter increases from the front side toward the rear. FIG. 10 shows, as an example, a longitudinal section at the fourth communication port 43D portion of the fourth valve chamber 35D of the main body 26 (a position corresponding to the section taken along the line CC in FIG. 3). When the wall portion 42D is tapered, the front mold 60 and the rear mold 61 when die-casting the main body 26 are arranged in the radial direction of the fourth valve chamber 35D at the position of the fourth communication port 43D. The fourth communication port 43D can be formed simultaneously with molding by bringing the molds 61 into contact with each other. Therefore, the cutting process after molding is reduced.

The seal body 28 is formed of rubber or cork, and has an area surrounding the first to fourth nozzle parts 32A to 32D on the upper side, first to fourth longitudinal groove parts 34A to 34D and the first to fourth gas inlets on the lower side. 38A to 38D collectively for each of the first to fourth branch channels 31A to 31D, and the region surrounding the recess 40 are positioned at the front surface of the main body 26. Positioning protrusions 46, 46, . . . for positioning the seal body 28 by passing through holes 45, 45, . . . formed in the seal body 28 are formed on the front surface of the main body 26.

The lid body 27 is a press-molded metal plate having substantially the same shape as the main body 26 when viewed from the front. A peripheral edge part 50 that covers the outer circumference of the main body 26 is formed on the outer periphery of the lid body 27, and a portion between the peripheral edge part 50 and the first to fourth branch channels 31A to 31D is sealed to the main body 26 from the front. The body 28 is penetrated and screwed by screws 55, 55, . . . (FIG. 3). As shown by the two-dot chain line in FIG. 7, on the front surface of the lid body 27, there is a groove that bulges forward and overlaps from the front across the first nozzle part 32A, the first longitudinal groove part 34A, and the first gas inlet 38A. 1 vertical bulge portion 51A is formed. As a result, a first branch flow path 31A is formed. Similarly, on the front surface of the lid body 27, a second vertically bulging portion 51B is formed, which straddles the second nozzle portion 32B, the second vertical groove portion 34B, and the second gas inlet 38B, overlaps from the front, and bulges forward. As a result, a second branch flow path 31B is formed. Similarly, on the front surface of the lid body 27, a third vertically bulging portion 51C is formed which straddles the third nozzle portion 32C, the third vertical groove portion 34C, and the third gas inlet 38C, overlaps from the front, and bulges forward. As a result, a third branch flow path 31C is formed. Similarly, on the front surface of the lid body 27, a fourth vertically bulging portion 51D is formed which straddles the fourth nozzle portion 32D, the fourth vertical groove portion 34D, and the fourth gas inlet 38D, overlaps from the front, and bulges forward. As a result, a fourth branch flow path 31D is formed.

In the lid body 27, a lower bulge 52 extending in the left-right direction is formed below the first to fourth vertical bulges 51A to 51D. As shown by the two-dot chain line in FIG. 7, the lower bulging portion 52 has approximately the same horizontal width and approximately half the vertical width as the recess 40 of the main body 26, and overlaps from the front on the lower half side of the recess 40. The main flow path 30 is formed by the lower bulge 52 and the recess 40.
In addition, on the inner surface of the lower side of the lower bulging part 52, at a position corresponding to the front of the lower protruding parts 44, 44, etc., there is a semicircle extending upwardly inside the lower bulging part 52 when viewed from the front, as shown in FIG. Guide portions 53, 53, . . . that protrude in a shape are formed. The guide portion 53 and the lower protrusion 44 form a screw-fastening portion 54 that screws the peripheral portion 50 of the lid body 27. That is, the peripheral portion 50 is screwed by screwing a screw 55 passed through a through hole formed in the lid body 27 on the lower side of the guide portion 53 into a screw hole provided at the center of the lower protrusion 44. It turns out.

In this gas distribution unit 5, the seal body 28 is set on the front surface of the main body 26 in which the solenoid valves 36, 36, . do. In this state, cover the lid body 27 from the front and screw the screws 55, 55, etc. that passed through the lid body 27 and the seal body 28 into each screw hole provided in the main body 26, and the assembly of the gas distribution unit 5 is completed. do.
The main body 26 of the gas distribution unit 5 assembled in this way is screwed to the lower front surface of the inner case 20 from the front, and the gas outlet portion 21 of the gas proportional valve unit 17 is screwed to the gas inlet 29 of the main body 26 from the rear. For example, the assembly of the gas distribution unit 5 to the combustion device 3 is completed.

(Explanation of water heater operation)
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 detects this and controls the main solenoid of the gas proportional valve unit 17. While opening the valve 19, the proportional valve 18 is controlled to a predetermined opening degree at the time of ignition. Moreover, if the controller is used on the bath side, the controller opens the solenoid valve 36 of the first valve chamber 35A of the corresponding first branch flow path 31A. Further, if the controller is used on the hot water supply side, the controller opens the solenoid valves 36 of the second to fourth valve chambers 35B to 35D in the corresponding second to fourth branch channels 31B to 31D. At the same time, the controller operates the air supply fan 6 to supply combustion air. Fuel gas is thus supplied to the gas distribution unit 5 via the gas proportional valve unit 17 .
Then, when the discharge electrode provided in the inner case 20 continuously discharges by the controller, the air-fuel mixture ejected from the flame hole of each concentration burner is combusted. The combustion exhaust gas from the burner unit is heat exchanged with water passing through the heat exchanger tube of the primary heat exchanger 4A and the heat absorption tube of the secondary heat exchanger 4B, and is turned into hot water at a set temperature and discharged from the hot water outlet pipe 8. The controller adjusts the opening degree of the proportional valve 18 according to the required combustion amount, adjusts the amount of fuel gas supplied from the gas proportional valve unit 17, and continuously changes the rotation speed of the air supply fan 6. to maintain a predetermined air-fuel ratio. In addition, when the controller is used on the hot water supply side, the solenoid valves 36 of the second to fourth valve chambers 35B to 35D in the second to fourth branch flow paths 31B to 31D of the gas distribution unit 5 are adjusted according to the required combustion amount. By controlling the opening and closing of the burner group, the second to fourth burner groups are selected and the number of combustion burners is controlled in stages.

At this time, in the gas distribution unit 5, the fuel gas introduced from the gas introduction port 29 flows to the left in the main channel 30, and when using the bath, enters the first valve chamber 35A from the first communication port 43A, and enters the first valve chamber 35A from the first communication port 43A. The gas flows from the first gas inlet 38A to the first branch flow path 31A and is supplied to the first burner group. To explain in detail, when the fuel gas flows through the main flow path 30, it collides with the first upper protrusion 41A that protrudes downward from the upper inner surface and goes around to the lower side of the first upper protrusion 41A, as shown by the dotted line in FIG. Resistance is provided and momentum is weakened. However, since the first upper protrusion 41A has a semicircular shape when viewed from the front, it is smoothly guided downward and the resistance does not become excessive. Further, a lower protrusion 44 that protrudes upward is provided on the lower inner surface of the recess 40 between the first upper protrusion 41A and the second upper protrusion 41B, and a lid is provided at the same position. Since the guide portion 53 is also provided in the lower bulging portion 52 of the body 27, the fuel gas is guided toward the first communication port 43A as shown by the dotted line arrow in FIGS. 7 and 12. Therefore, the flow of fuel gas can also be reduced on the upstream side of the main flow path 30 to promote the flow toward the first communication port 43A. However, here, since the first communication port 43A faces downstream, the fuel gas makes a U-turn upward, and an appropriate amount can be supplied to the first valve chamber 35A. This also applies when the second branch flow path 31B is used on the hot water supply side.

When simultaneously using the third and fourth branch channels 31C and 31D on the downstream side of the main channel 30, the fuel gas that has passed through the first and second upper protrusions 41A and 41B is indicated by the dotted line arrows in FIGS. As shown, the direction changes upward from directly below the third and fourth upper protrusions 41C and 41D, and flows from the third and fourth communication ports 43C and 43D to the third and fourth valve chambers 35C and 35D, respectively. It turns out.
In this way, even in the first and second branch channels 31A and 31B to which fuel gas is supplied from the upstream side of the main channel 30, since the two first and second upper protrusions 41A and 41B are arranged, An appropriate amount of fuel gas can be supplied by promoting the flow of fuel gas to the first and second communication ports 43A and 43B.
On the contrary, even if the third and fourth branch channels 31C and 31D are supplied with fuel gas from the downstream side of the main channel 30, an appropriate amount can be supplied.

(Effects of the invention related to the first to fourth upper protrusions and the first to fourth communication ports)
The gas distribution unit 5 and water heater 1 of the above configurations include a casing 25, a gas inlet 29 formed in the casing 25, and a main channel formed in the casing 25 and communicating with the gas inlet 29 and extending in the left-right direction. 30, first to fourth branch channels 31A to 31D formed in the casing 25 and branched from the main channel 30 and extending upward, and casing at the upstream ends of the first to fourth branch channels 31A to 31D. A plurality of electromagnetic valves 36 are provided in the casing 25 and can open and close each upstream end, respectively, and a plurality of electromagnetic valves 36 are provided in the casing 25 at the downstream ends of the first to fourth branch flow paths 31A to 31D, and the first to fourth burners The casing 25 includes a plurality of nozzles 33 that supply fuel gas to groups (a predetermined number of burners), and forms the upstream ends of the first to fourth branch channels 31A to 31D. First to fourth upper protrusions 41A to 41D (protrusions) protruding downward are formed respectively on the lower surfaces of the first to fourth upper protrusions 41A to 41D, and the first to fourth branch channels 31A to 41D are formed on the lower surfaces of the first to fourth upper protrusions 41A to 41D, respectively. First to fourth communication ports 43A to 43D are respectively formed to communicate the upstream end of 31D with the main flow path 30.

With this configuration, it is possible to prevent the fuel gas immediately after entering the main flow path 30 from the gas inlet 29 from being forcefully supplied into the first and second branch flow paths 31A and 31B on the upstream side. Therefore, fuel gas can be supplied in an appropriate amount to the third and fourth branch channels 31C and 31D on the downstream side, and fuel gas can be uniformly supplied to each burner group. Further, since the first to fourth upper protrusions 41A to 41D protrude into the main flow path 30, the orientations of the first to fourth communication ports 43A to 43D can be easily set.

Particularly here, the first and second communication ports 43A and 43B in the first and second upper protrusions 41A and 41B located on the upstream side of the main flow path 30 are opened toward the downstream side of the main flow path 30. There is.
Therefore, the fuel gas flowing from the main flow path 30 to the first and second upper protrusions 41A, 41B can be more effectively deenergized.
Further, the first and second upper protrusions 41A and 41B located on the upstream side are formed in a semicircular shape when viewed from the front.
Therefore, the resistance to the flow of fuel gas can be prevented from becoming excessively high, and smooth flow can be ensured.
Furthermore, the amount by which the first and second upper protrusions 41A and 41B protrude into the main flow path 30 is more than half the vertical width of the main flow path 30.
Therefore, the flow of fuel gas near the gas inlet 29 can be appropriately reduced. Therefore, it is possible to promote the circulation of fuel gas and supply an appropriate amount of fuel gas to the first and second branch channels 31A and 31B on the upstream side, and also to make it possible to supply an appropriate amount of fuel gas to the third and fourth branch channels on the downstream side. A certain amount or more of fuel gas can also be supplied to 31C and 31D.

In the invention related to the first to fourth upper protrusions and the first to fourth communication ports, the amount of protrusion of each upper protrusion into the main flow path is not limited to the above embodiment. For example, only the first upper protrusion may be made more than half the vertical width of the main channel, and the other upper protrusions may be less than half the vertical width. The shape in front view is not limited to a semicircle, but also semi-elliptical, semi-elliptical, semi-hexagonal, etc.
The sizes, directions, etc. of the first to fourth communication ports are not limited to the above embodiments. The first and second communication ports may also be formed downward like the third and fourth communication ports.

(Effects of the invention related to the guide section provided in the lower bulge)
The gas distribution unit 5 and the water heater 1 of the above configuration include a casing 25 including a die-cast body 26, a press-molded lid 27 fixed to the front surface of the body 26, and a gas formed in the body 26. A main channel 30 formed by the inlet 29 , a recess 40 provided in the main body 26 , and a lower bulge 52 provided in the lid 27 and extending in the left-right direction in communication with the gas inlet 29 , and a main channel 30 provided in the main body 26 The first to fourth longitudinal grooves 34A to 34D and the first to fourth vertical bulges 51A to 51D provided on the lid body 27 branch from the main flow path 30 and extend upward. The upstream ends of the branch channels 31A to 31D and the first to fourth branch channels 31A to 31D respectively accommodate electromagnetic valves 36 which are provided in the main body 26 and whose upstream ends can be opened and closed. First to fourth valve chambers 35A to 35D equipped with first to fourth communication ports 43A to 43D that communicate with the main flow path 30 on the upstream side, and downstream ends of the first to fourth branch flow paths 31A to 31D. A plurality of nozzles 33 are provided on the main body 26 and supply fuel gas to the first to fourth burner groups. A guide portion 53 is formed to guide the flowing fuel gas toward the recess 40 side.
With this configuration, the fuel gas in the lower bulging portion 52 of the lid body 27 can flow toward the recess 40 on the back side. Therefore, it is possible to prevent the fuel gas from passing through the first to third branch channels 31A to 31C on the upstream side, and it is possible to uniformly supply the fuel gas to each burner group.

Particularly here, the guide portion 53 is arranged so as to be located between the first to third communication ports 43A to 43C adjacent in the left and right direction when viewed from the front.
Therefore, fuel gas can be effectively guided to the first to third communication ports 43A to 43C.
The lower portions of the first to fourth valve chambers 35A to 35D protrude from the upper inner surface of the recess 40 to the upper half region of the recess 40 to form first to fourth upper protrusions 41A to 41D that are semicircular in front view. The first to fourth communication ports 43A to 43D are formed on the lower surfaces (circumferential surfaces) of the first to fourth upper protrusions 41A to 41D, respectively, while the lower bulging portion 52 is formed under the recessed portion 40. It is located at the front of the half area.
Therefore, the fuel gas whose energy is reduced by the first to third upper protrusions 41A to 41C and guided to the lower side of the recess 40 is efficiently transferred to the first to third communication ports 43A to 43C by the lower bulging part 52. It will be possible to guide you towards.

On the other hand, the guide portion 53 has a planar surface protruding toward the recess 40 and serves as a screw fixing portion 54 for screwing the lid 27 to the main body 26 .
Therefore, the guide portion 53 has a rational configuration that is used for screwing, and the shape of the lid body 27 is simplified.
Further, a lower protrusion 44 is formed on the lower inner surface of the recess 40 and protrudes into the lower half region of the recess 40 and overlaps the protrusion surface of the guide portion 53 in the front-rear direction, and the front surface of the lower protrusion 44 is flat. A screw 55 formed in a shape and screwing the guide portion 53 to the main body 26 is screwed together.
Therefore, the fuel gas can be effectively guided to the first to third communication ports 43A to 43C by the lower protrusion 44, and the lower protrusion 44 can be used for screwing, resulting in a rational configuration.

In addition, in the invention related to the guide part provided in the lower bulging part, the shape and number of the guide parts are not limited to the above-mentioned form. For example, if it is not used for screwing, the protruding surface may not be flat, but may be an inclined surface or an inclined curved surface that protrudes toward the recess as it goes downstream. The guide portion may be provided above the lower bulging portion instead of below, or may not be provided between the communication ports.

(Effects related to the invention in which the gas inlet is formed to protrude in the same direction as the valve chamber)
The gas distribution unit 5 and water heater 1 of the above configurations include a casing 25 including a die-cast die-cast main body 26 having a rectangular shape in front view, a cover 27 fixed to the front surface of the main body 26 and press-molded, and the main body 26. a main channel 30 formed by a recess 40 provided in the main body 26 and a lower bulge 52 provided in the lid body 27, communicating with the gas introduction port 29 and extending in the left-right direction; , is formed by the first to fourth vertical grooves 34A to 34D provided on the main body 26 and the first to fourth vertical bulges 51A to 51D provided on the lid body 27, and branches from the main flow path 30 and extends upward. The first to fourth branch channels 31A to 31D are provided at the upstream ends of the first to fourth branch channels 31A to 31D at the lower rear surface of the main body 26, respectively, and open rearward, and are provided at the upstream end. The solenoid valves 36, which can be opened and closed by the valve body 37 that moves the valve seat 39 forward and backward in the front and rear directions, are accommodated from the rear, and there are first to fourth communication ports 43A communicating with the main flow path 30 on the upstream side of the solenoid valves 36. -43D are provided in the main body 26 at the downstream ends of the first to fourth branch channels 31A to 31D, and the first to fourth burner groups are provided with fuel. The gas introduction port 29 is formed to protrude from the rear surface of the main body 26 in the same direction as the opening direction of the first to fourth valve chambers 35A to 35D.

With this configuration, it is possible to eliminate portions that protrude outward from the upper and lower edges of the main body 26. Therefore, the upper edge and the lower edge of the main body 26 can be formed linearly and parallel to each other, and the hot water inlet and outlet can be linearly arranged. Therefore, during molding, the flow direction of the hot water is easily aligned in one direction, improving the flowability of the hot water inside the mold, and improving the finish of the molded product. Further, since there is no part projecting downward from the main body 26, the vertical width of the main body 26 can be shortened, and the distance between the inlet and the valve seat 39 can be narrowed. Therefore, the occurrence of "s" can be prevented, and damage such as chipping when cutting the valve seat 39 is less likely to occur, so that the yield can be significantly improved.
Furthermore, since the gas inlet 29 is formed to protrude rearward in the same way as the first to fourth valve chambers 35A to 35D, molding can be performed using only front and rear split molds, reducing costs such as mold costs and management costs. It is possible to suppress the increase.

Particularly here, the lower portions of the first to fourth valve chambers 35A to 35D each protrude into the recess 40 from the upper inner surface of the recess 40 in a semicircular shape when viewed from the front.
Therefore, the first to fourth communication ports 43A to 43D formed at the upstream ends of the first to fourth branch paths 31A to 31D can be arranged closer to the lower side of the main body 26, and the hot water inlet The distance between the valve seat 39 and each valve seat 39 around the first to fourth communication ports 43A to 43D can be further shortened. Therefore, the area around the valve seat 39 can be filled with high-pressure hot water, and the generation of "s" can be effectively suppressed, leading to further improvement in yield.
Further, the lower circumferential surfaces of the first to fourth valve chambers 35A to 35D are formed in a tapered shape that widens from the front to the rear, and the first to fourth communication ports 43A to 43D are formed on the circumferential surface. has been done.
Therefore, a part of the front mold 60 and a part of the rear mold 61 of the main body 26 are overlapped in the radial direction of the first to fourth valve chambers 35A to 35D to open the first to fourth communication ports 43A to 43D. It becomes possible to form. Therefore, the cutting process involved in forming the first to fourth communication ports 43A to 43D can be reduced, and manufacturing costs can be reduced.

In the invention in which the gas inlet is formed to protrude in the same direction as the valve chamber, the position of the gas inlet is not limited to the above-mentioned configuration, and can be changed as appropriate, such as at the left end of the main body. The protruding shape of the lower part of the valve chamber is not limited to a semicircular shape when viewed from the front, and instead of having a tapered shape that widens from the front to the rear, it may have an equal diameter from front to back.

In each invention, the number of branch channels is not limited to the above embodiment, and can be increased or decreased as appropriate. Therefore, the number of valve chambers and electromagnetic valves may be increased or decreased according to the branched flow paths. The number of nozzles in each branch channel is also not limited to the above embodiment.
The configuration of the water heater itself is not limited to the above-mentioned configuration, and may be of a type that does not include a secondary heat exchanger or a type that does not include a circuit on the bath side.

1. Water heater, 2. Housing, 3. Combustion device, 4. Heat exchanger, 5. Gas distribution unit, 8. Hot water outlet pipe, 9. Water supply pipe, 12. Gas inlet. 13...Water inlet, 14...Hot water outlet, 17...Gas supply unit, 20...Inner case, 25...Casing, 26...Main body, 27...Lid body, 28...Seal body, 29... Gas inlet, 30...Main channel, 31A-31D...1st to 4th branch channel, 32A-32D...1st to 4th nozzle portion, 33...Nozzle, 34A-34D...1st to 4th longitudinal groove, 35A to 35D...1st to 4th valve chamber, 36...Solenoid valve, 38A to 38D...1st to 4th gas inlet, 40...Recess, 41A to 41D...1st to Fourth upper protrusion, 42A to 42D...first to fourth lower wall parts, 43A to 43D...first to fourth communication ports, 44...lower protrusion, 51A to 51D...first to fourth 4 Vertical bulge portion, 52: Lower bulge portion, 53: Guide portion, 54: Screw fixing portion.

Claims (4)

A gas distribution unit assembled in a combustion device accommodating a plurality of burners and distributing and supplying fuel gas to the burners,
casing and
a gas inlet formed in the casing;
a main channel formed in the casing, communicating with the gas inlet and extending in the left-right direction;
a plurality of branch channels formed in the casing, branching from the main channel and extending upward;
a plurality of electromagnetic valves each provided in the casing at an upstream end of each branch flow path and capable of opening and closing each upstream end;
a plurality of nozzles each provided in the casing at a downstream end of each branch flow path and supplying fuel gas to a predetermined number of the burners;
The casing forming the upstream end of each branch flow path is formed with a protrusion that protrudes downward into the main flow path, and the upstream end is connected to the main flow path on the lower surface of each protrusion. A communication port is formed to communicate with the
A gas distribution unit characterized in that the communication port in one or more of the protrusions located upstream of the main flow path opens toward the downstream side of the main flow path . The gas distribution unit according to claim 1 , wherein the protrusion located on the upstream side is formed in a semicircular shape when viewed from the front. 3. The gas distribution unit according to claim 1 , wherein the protrusion amount of the protrusion located on the upstream side into the main flow path is equal to or more than half of the vertical width of the main flow path. A water heater comprising the gas distribution unit according to any one of claims 1 to 3 assembled to a combustion device that accommodates a plurality of burners.

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