JPS6360285B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a gas combustion device that is used as a heating device for a heat exchanger such as a water heater or a space heater, and whose combustion capacity can be switched in two stages, large and small.

(b) Conventional technology A conventional gas combustion device of this type was disclosed in Japanese Patent Application Laid-Open No.
As disclosed in Publication No. 31719 and Japanese Utility Model Application Publication No. 55-131452, a gas burner is composed of two groups of burner elements, two fuel supply paths each having an on-off valve are connected to these groups of burner elements, By separately supplying gas fuel, the combustion capacity can be switched into two stages, large and small.

However, because one burner element group is installed next to the other burner element group, when switching from low-capacity combustion to high-capacity combustion, the flame transfer is slow and there is a risk that a large amount of raw gas will be released. Ta. In addition, there was a drawback that the entire heat exchanger was not heated uniformly during low capacity combustion, resulting in local heating. Furthermore, in such a gas combustion device, two fuel supply passages are branched from the main fuel supply passage, and one gas governor is provided in the main fuel supply passage, so the gas flow rate may change significantly and the fuel chamber The governor characteristics could not adequately follow changes in the furnace pressure. For this reason, there has been a problem in that it is difficult to adjust the gas pressure to an appropriate level using the gas governor for both low-capacity combustion and high-capacity combustion.

(c) Problems to be Solved by the Invention The object of the present invention, which was made in view of the above-mentioned prior art, is to prevent local heating of the heat exchanger during low-capacity combustion while changing from low-capacity combustion to high-capacity combustion. The purpose is to ensure that the switching is carried out quickly and further to appropriately adjust the gas pressure during low capacity combustion and during high capacity combustion.

(d) Means for solving the problem According to the present invention, the above problem is solved by having a gas burner disposed below a heat exchanger and consisting of two burner element groups, an on-off valve, and a gas governor, two fuel supply paths that separately supply gas fuel to two burner element groups of the gas burner, one burner element group of the gas burner is located in the middle of the other burner element group, and one burner element group This problem can be solved by setting the governor setting pressure of the fuel supply passage of one burner element group lower than the governor setting pressure of the fuel supply passage of the other burner element group.

(e) Operation When the on-off valve of one fuel supply path is opened and gas fuel is supplied to one burner element group, the gas burner performs combustion at a small capacity. Next, when the on-off valve of the other fuel supply path is opened and gas fuel is supplied to the other burner element group, the gas burner performs combustion at a small capacity.

Since one burner element group is disposed in the middle of the other burner element group, the gas burner performs combustion in the center during low capacity combustion and uniformly heats the heat exchanger. Moreover, when switching from low capacity combustion to high capacity combustion, fire is quickly transferred from one burner element group to the other burner element group. In addition, since gas governors are provided on both fuel supply paths, it is easy to adjust the gas pressure during low-capacity combustion and high-capacity combustion. Since the pressure is set lower than the set pressure, there is no need to worry about the gas flow rate becoming larger than necessary during small capacity combustion when the furnace pressure in the combustion chamber is low.

(F) Embodiment Hereinafter, an embodiment in which the present invention is applied to a forced air supply/exhaust type water heater will be described.

In FIG. 1, 1 is a combustion tube with a combustion chamber 2 inside and a water tube 3 wound around it; 4 is a heat exchanger that is disposed above the combustion chamber 2 and instantaneously heats the water flowing through the water tube 3; 5 is an exhaust hood that is connected to the upper part of the combustion tube 1 and collects the combustion gas that has passed through the heat exchanger 4;
6 is an exhaust pipe, 7 is a burner box connected to the lower part of the combustion tube 1, 8 is a Bunsen type gas burner housed in the burner box 7, 9 is a blower that supplies combustion air into the burner box 7, and 10 is a blower. Partition plates 11, 12, 1 that divide the air supplied into the burner box 7 into primary air and secondary air.
Reference numeral 3 denotes a rectifying plate that has a large number of small holes and equalizes the pressure of the secondary air flow, and 14 a distribution box that is connected to the side of the burner box 7 and supplies gas fuel to the gas burner 8 through nozzles 15. It is.

The gas burner 8 consists of ten burner elements 80 to 89 as shown in FIG.
to 85 form the first burner element group 8A, burner elements 80 to 82 and burner elements 86 to 89.
and constitute a second burner element group 8B. Further, the first burner element group 8A is interposed in the middle of the second burner element group 8B. Second
In the figure, 16 is the main fuel supply path, 17 and 1
8 is branched from the main fuel supply path 16 and is connected to the distribution box 14
The first burner element group 8A and the second burner element group
The first burner element group 8B supplies gas fuel to the burner element group 8B.
and a second fuel supply path. The first fuel supply path 17 is provided with a gas governor 19 and on-off valves 20 and 21 which are made up of two solenoid valves, and the second fuel supply path 18 is also provided with an on-off valve which is made up of a gas governor 22 and two solenoid valves. Valves 23 and 24 are interposed. Further, the set pressure of the gas governor 19 is set to 31 mmAq, and the set pressure of the gas governor 22 is set to 33 mmAq.

As shown in FIGS. 3 and 4, the distribution box 14 has gas inlets 25 and 26 to which the fuel supply channels 17 and 18 are connected, respectively, and ten nozzle mounting holes 270 to 279. Gaseous fuel flowing in from the gas inlet 26 is distributed and supplied to the nozzle mounting holes 273 to 275, and gaseous fuel flowing in from the gas inlet 26 is distributed and supplied to the nozzle mounting holes 270 to 272 and the nozzle mounting holes 276 to 279.

When the on-off valves 20 and 21 of the combustion supply path 17 are opened, the gas fuel in the main fuel supply path 16 passes through the fuel supply path 17, and after the gas pressure is adjusted by the gas governor 19, it is transferred from the distribution box 14 to the first gas fuel. Burner element group 8
A is supplied to burner elements 83 to 85. Further, part of the combustion air introduced into the burner box 13 by the operation of the blower 9 is transferred to the burner element 80.
to 89 as primary air, and the remainder is used as secondary air in the combustion chamber 2 after rising between the burner elements via the rectifying plates 11 to 13.
Then, when the mixture of gas fuel and primary air mixed in the burner elements 83 to 85 is ignited,
The gas burner 8 starts combustion at a small capacity. Since this small capacity combustion takes place in the center of the gas burner 8, the combustion gas rises up the combustion chamber 2 and passes through the heat exchanger 4.
It heats up evenly, so you don't have to worry about localized heating. The exhaust gas that has passed through the heat exchanger 4 is then exhausted from the exhaust hood 5 through the exhaust pipe 6.

Next, when the on-off valves 23 and 24 of the fuel supply path 18 are opened, the gaseous fuel in the main fuel supply path 16 is divided and flows into the fuel supply paths 17 and 18. After the gas pressure of the gas fuel in the fuel supply path 18 is adjusted by the gas governor 22, it is passed through the distribution box 14 to the burner elements 80 to 8 of the second burner element group 8B.
2 and burner elements 86 to 89. At this time, since the first burner element group 8A is located in the middle of the second burner element group 8B,
burner elements 83 to 85 to burner elements 80 to 82 on both sides and burner elements 86 to 89;
The flame quickly transfers to the gas burner 8, and the gas burner 8 starts burning at a high capacity.

According to this embodiment, the first
Since the burner element group 8A is arranged in the middle part of the second burner element group 8B, the gas burner 8 performs combustion in the center part during low capacity combustion, and heats the heat exchanger 4 uniformly. Therefore, there is no need to worry about local heating of the heat exchanger 4, unlike in the conventional case. Moreover, when switching from low capacity combustion to high capacity combustion, the flame transfer from the first burner element group 8A to the second burner element group 8B is performed quickly, and it is possible to prevent a large amount of raw gas from being released. In addition, since the gas governors 19 and 22 are provided in the combustion supply paths 17 and 18, respectively, the gas governors 19 and 22 can follow changes in the gas flow rate well, and the gas pressure during low-capacity combustion and high-capacity combustion can be adjusted. Adjustments can be made easily.
In addition, since the set pressure of the gas governor 19 is lower than the set pressure of the gas governor 22, it is possible to prevent the gas flow rate from flowing more than the set amount during small-capacity combustion, where the furnace pressure in the combustion chamber 2 is lower than during high-capacity combustion. It can be prevented. Furthermore, since the air volume of the blower 9 was not controlled during low capacity combustion and high capacity combustion, and the air volume was kept constant, excess air was generated during low capacity combustion, where condensation is likely to occur, lowering the dew point temperature and causing heat generation. Condensation on the exchanger 4 can be prevented.

(G) Effects of the invention Since this invention is configured as described above,
Even during low-capacity combustion in which only the first burner element group performs combustion, the heat exchanger is heated uniformly, and there is no fear of local heating. Furthermore, when switching from low capacity combustion to high capacity combustion, the flame is quickly transferred from the first burner element group to the second burner element group, and a large amount of raw gas can be prevented from being released. Furthermore, the gas pressure during small capacity combustion and large capacity combustion is
It exhibits excellent effects, such as being able to adjust appropriately with each gas governor and also mitigating the effects of fluctuations in the furnace pressure in the combustion chamber.

[Brief explanation of drawings]

The drawings show an embodiment in which the gas combustion device of the present invention is applied to a water heater, and FIG. 1 is a schematic sectional view of the water heater, FIG. 2 is a fuel system diagram of a gas burner, and FIG. 3 is used in FIG. 1. Figure 4 is a side view of the distribution box.
It is a sectional view taken along the line A-A' in the figure. 4... Heat exchanger, 8... Gas burner, 8A, 8
B... Burner element group, 80-89... Burner element, 17, 18... Fuel supply path, 19, 22...
Gas governor, 20, 21, 23, 24...open/close valve.

Claims (1)

[Claims] 1 A gas burner arranged below the heat exchanger and consisting of two burner element groups, an on-off valve, and a gas governor, and two fuel supply paths that separately supply gas fuel to the two burner element groups of the gas burner. and locating one burner element group of the gas burner in the middle of the other burner element group,
A gas combustion device characterized in that the governor set pressure of the fuel supply pipe of one burner element group is lower than the governor set pressure of the other burner element group.