JP2001027413A - Combustion control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the combustion allowance by increasing the number of combustion stages. SOLUTION: The combustion stages in which the number of burners is changed to six, four and seven by switching unit 4-6 are stored in a controller for each stage in advance. Only the center unit 5 achieves the combustion in the first stage, only the right unit 6 achieves the combustion in the second stage, the units 5, 6 achieve the combustion in the third stage, and total units 4-6 achieve the combustion in the fourth stage. Thus, four, seven, eleven and seventeen combustion stages are obtained in the first, second, third and fourth stage, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater comprising a plurality of burner units each comprising a plurality of burners, and by individually switching the combustion state of each burner unit, the combustion capacity can be controlled in multiple combustion stages. And the like.

[0002]

2. Description of the Related Art A combustion control device such as a water heater is provided with a burner unit (hereinafter referred to as "unit") comprising a plurality of burners, and selects a switching solenoid valve provided in a branch pipe to each unit. By opening and closing, the combustion state of each unit can be individually switched, and the number of burners to be burned can be changed stepwise. For example, as shown in FIG. 4, in the case where the burner includes four units 20, six units 21, and seven units 22 respectively, only one unit 20 is burned when the combustion stage is one stage, and the unit is burned in two stages. 2
In general, three combustion stages are set by burning 0 and 21 and burning all units 20 to 22 in three stages. In this case, the number of burners burning is 4
This will be changed to 10, 10 and 17.

[0003]

As described above, in the conventional combustion control apparatus, when the number of stages increases, new units are sequentially added to the previous stage, so that the number of units is reduced. Only the same number of steps can be obtained. Further, in such switching, the change in the number of burners becomes large even between the preceding and subsequent combustion stages, so that there is no margin for combustion.

[0004] Therefore, the first aspect of the present invention is to provide a combustion control device capable of obtaining a large number of combustion stages and reducing a change in each stage, and securing a wide combustion range while maintaining a margin of combustion. It is intended for.

[0005]

According to a first aspect of the present invention, the number of burners in at least one of the burner units is different from that of the other burner units. In the combustion step, a case is provided in which a plurality of the burner units each having a different number of the burners burn independently, and the number of the combustion steps is larger than the number of the burner units. . In addition to the object of the first aspect, the invention according to the second aspect is to ensure that a fire occurs when the burner unit to be burned is changed due to a change in the combustion stage. After all of the burner units burning by any of them are once burned, the burner unit is shifted to the changed combustion stage. In addition to the object of claim 1 or 2, the invention according to claim 3 provides a method for performing all of the combustion stages in order to surely perform the fire in all the change patterns of the combustion stage, especially when the number of burner units is three or more. In the above change pattern, each combustion stage is set so that the burner units burning before or after the change are continuous.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a water heater 1 as a combustion control device. In a combustion chamber 2, a burner unit (hereinafter, referred to as "unit") 4 consisting of six burners for heating a heat exchanger 3 is provided. A unit 5 composed of six burners and a unit 6 composed of seven burners are provided. Each of the units 4 to 6 is connected to a branch pipe 8, 8,... Which branches from the gas pipe 7 to each of the units 4 to 6. Have been. Each branch pipe 8 is provided with a switching solenoid valve 9, and the gas pipe 7 before branching is provided with a proportional valve 10 and an original solenoid valve 11. On the other hand, below the combustion chamber 2, a fan 12 for supplying combustion air and a fan motor 13 are provided. 14 is a water supply pipe leading to the heat exchanger 3, 15 is a tapping pipe for sending out hot water from the heat exchanger 3, 16, 16,... Are flame rods provided for the units 4 to 6 for flame detection, and 17 is an ignition electrode. It is.
Reference numeral 18 denotes a controller that opens and closes the switching solenoid valve 9 and the original solenoid valve 11 for each unit 4 to 6 and adjusts the opening of the proportional valve 10 in accordance with a set temperature instructed by a remote controller (not shown). The combustion of each of the units 4 to 6 is switched, and multi-stage combustion control is executed. Controller 1
8 includes a fan 1 corresponding to a current value for controlling the proportional valve 10.
2 is stored in advance, and the controller 18 controls the fan motor 13 based on this data to execute air-fuel ratio control.

On the other hand, the combustion stages by switching the units 4 to 6 are stored in the controller 18 in advance for each stage. Specifically, the ON state of the three switching solenoid valves 9 is set to “1” and the OFF state is set to “0”, and “01” is set for each stage.
Data such as “0” and “011” are stored. FIG.
Indicates each stage by the combustion state of the unit, and the number in each unit is the number of burners. First, in the first stage, only the central unit 5 burns (data is “010”), and in the second stage, only the right unit 6 burns (data is “00”).
1)), the units 5 and 6 burn in the third stage (data “011”), and all units 4 to 6 burn in the fourth stage (data “111”). Thus, four burners can be used in one stage, seven can be used in two stages, 11 can be used in three stages, and 17 burners can be obtained in four stages. Further, in this embodiment, in all the change patterns, the units that burn when the OR is taken between the respective combustion stages are continuous, that is, when only the central unit 5 does not burn (data indicates “10”).
The arrangement of each unit 4 to 6 and each combustion stage are set so that 1)) does not occur. This is because, for example, when the stage of only the left unit 4 is set, there is a possibility that a fire may occur when shifting from the stage to the stage of only the right unit 6. This ensures that a smooth fire is always obtained.

Further, in this case, when the combustion of the units is exchanged, for example, when the combustion is switched between the first stage and the second stage, the fire cannot be started.
The fire control shown in the flowchart of FIG. 3 is executed. Hereinafter, the fire control will be described. First, S1
The open / closed state of the switching solenoid valves 9, 9,... Before the fire (hereinafter, referred to as “MV conditions before the fire”) and the opened / closed state of the switching solenoid valves 9, 9,. After MV condition), and determines whether or not this is different from the post-fire MV condition. For example, in the case of switching from the third stage (011) to the second stage (001), the result of the AND operation (001) becomes the same as the MV condition after the fire, so that the combustion of the unit 5 only needs to be stopped. Therefore, since the processing after S2 is unnecessary, switching to the next stage is immediately performed, and the combustion control in the next stage is executed as it is. However, if the result of S1 is different from the post-fire MV condition, for example, switching from the first stage (010) to the second stage (001), the fire start timer 1 is started in S2, and in the next S3, the fire start timer 1 is started. With the MV condition, the fan motor 13
Is changed to a pre-stored slow ignition rotation speed for ignition, and the current to the proportional valve 10 is changed to a slow ignition current for ignition. Then, in the determination of S4, if the rotation speed of the fan motor 13 reaches within ± 10% of the mild ignition rotation speed and the expiration of the fire start timer 1 is confirmed, the fire start timers 2 and 3 are respectively set in S5. Start.

Next, in S6, the OR of the MV condition before the fire and the MV condition after the fire is ORed, and based on the result, each switching solenoid valve 9 is opened and closed to burn each unit. For example, in the case of switching from one stage (010) to two stages (001), since the OR result is (011),
The units 5 and 6 are both in a combustion state. Here, if the fire timer 3 expires before the fire in the determination of S7,
In S8, a process such as a stop of combustion or a warning is performed as a fire transfer abnormality. Next, if it is determined in S9 that all the flame rods 16 of the units 5 and 6 that burn according to the time-up of the fire timer 2 and the OR result of S6 detect a flame, the fire timer 4 starts in S10, and then continues. In S11, MV after fire
The unit 6 is burned under the condition (001). And S
When the fire timer 4 times out in the determination of 12, the combustion control in the next stage is executed.

As described above, according to the above-described embodiment, a stage is provided in which each of the units 5 and 6 having a different number of burners is singly burned, and a stage number 4 exceeding the unit number 3 is obtained. Burners can be secured. Therefore,
Even with the same combustion capacity, it is possible to cope in a marginal combustion stage, and a wide combustion range can be secured, so that the combustion performance is improved. When the combustion stage is switched, AND of the fire MV conditions before and after the switch is performed, and if the result is different from the fire MV condition after the switch, the OR of the fire MV condition is calculated by ORing the fire MV conditions. As a result, the unit is once burned, and then the process proceeds to the next combustion stage, so that even if the unit that burns alone is replaced, the fire can be reliably transferred. In particular, here, in the setting of the first combustion stage, the unit that burns when the OR is taken between the combustion stages of all the change patterns is made continuous, so that the unit that does not burn does not occur in between, A smooth fire transfer can be realized in all the change patterns.

Although the above embodiment has been described as a type having three units, even if the number of units is two (for example, the number of burners is four and seven), it is the same as in the above embodiment. In addition, by providing a stage in which each of the burners is individually burned, it is possible to increase the number of stages of the number of intermediate burners, and similarly, by adopting the fire control, it is possible to reliably perform a smooth fire transfer. . This is the same even if there are four or more units. Further, in the above embodiment, the number of burners between the units is all different, but if the number of burners of at least one unit is different from the other units, the step of burning a unit having a different number of units independently is performed. Since the number of burners can be obtained in the middle by providing the unit, there is no problem even if there is a unit having the same number of burners.

[0012]

According to the first aspect of the present invention, the number of burners in at least one burner unit is different from that of the other burner units, and a plurality of burners having different numbers of burners in the combustion stage. By providing a case in which each of the units burns independently and setting the combustion stage to be larger than the number of burner units, an intermediate number of burners can be secured. Therefore, it is possible to cope with the same combustion capacity in a marginal combustion stage, and a wide combustion range can be secured, so that the combustion performance is improved. According to the second aspect of the present invention, in addition to the effect of the first aspect, when the burner units that burn due to the change of the combustion stage are replaced, all the burner units that burn before or after the change are once burned. After that, by moving to the changed combustion phase,
Even when the above-mentioned burner unit is replaced, the fire can be surely made. According to the third aspect of the present invention, in addition to the effects of the first or second aspect, in the case where there are three or more burner units, the burner unit burns before or after any change in all the change patterns of the combustion stage. By setting each combustion stage so as to be continuous, it is possible to surely perform the fire in all the change patterns.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a water heater.

FIG. 2 is an explanatory diagram showing a combustion stage.

FIG. 3 is a flowchart of a fire control.

FIG. 4 is an explanatory view showing a conventional combustion stage.

[Explanation of symbols]

1. hot water heater, 2. combustion chamber, 3. heat exchanger, 4,
5, 6 burner unit, 7 gas pipe, 9 switching solenoid valve, 10 proportional valve, 12 fan, 18 controller.

Claims (3)

[Claims] 1. A combustion control device comprising a plurality of burner units each comprising a plurality of burners, wherein a combustion state of each of the burner units is individually switched to control a combustion capacity in multiple combustion stages, The number of the burners in at least one of the burner units is different from that of the other burner units, and the plurality of burner units having the different numbers of the burners burn independently in the combustion stage. A combustion control device, wherein the number of combustion stages is greater than the number of the burner units. 2. When the burner units that burn due to a change in the combustion stage are switched, the burner units that burn before or after the change are all burned once, and then the combustion stage is shifted to the changed combustion stage. The combustion control device according to claim 1. 3. When the number of burner units is three or more, each combustion stage is set so that the burner units that burn before or after the change are continuous in all the change patterns of the combustion stage. 3. The combustion control device according to item 1.