JP2009156522A - Combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion device capable of further improving accuracy in discriminating abnormality in a combustion state while properly suppressing chattering in switching the number of combustion burners. <P>SOLUTION: In this combustion device wherein a control means is constituted to switch the number of combustion burners so that the more the target fuel supply amount is, the more the number of combustion burners is, in controlling a fuel supply state adjusting means, and disposing an overlap portion of a fuel supply amount between a maximum target fuel supply amount and a minimum target fuel supply amount by setting the maximum target fuel supply amount to keep the stage to be larger than the minimum target fuel supply amount to keep the next stage at a side of increasing the number of combustion burners with respect to the stage in switching the number of combustion burners, the control means is constituted to change a width of the overlap portion in controlling the fuel supply state adjusting means to be large or small in the form of changing the minimum target fuel supply amount to keep the stage to be large or small in switching the number of combustion burners. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention provides a burner having a plurality of burner parts,
Fuel supply state adjusting means for switching the number of combustion burner portions to be in a fuel supply state in the plurality of burner portions to a plurality of stages and adjusting the fuel supply amount to the combustion burner portion;
A combustion state detecting means provided to be located in a flame formed in the burner portion, and outputting information according to the combustion state of the burner portion;
Whether or not the burner combustion state is abnormal based on combustion adjustment control for controlling the fuel supply state adjusting means by obtaining a target fuel supply amount corresponding to the combustion load and output information of the combustion state detecting means And a control means for performing combustion state determination control for determining
In the control of the fuel supply state adjustment means, the control means increases the number of combustion burner parts as the target fuel supply amount increases, and maintains the stage in switching the number of combustion burner parts. The maximum target fuel supply amount and the minimum target fuel supply are set by setting the fuel supply amount to be larger than the minimum target fuel supply amount for maintaining the stage in the next stage on the side where the number of combustion burner parts is increased from that stage. The present invention relates to a combustion apparatus configured to provide an overlap portion of a fuel supply amount between the combustion burner and switch the number of combustion burner portions.

Such a combustion apparatus controls the combustion of the burner by obtaining the target fuel supply amount of the burner according to the combustion load and controlling the fuel supply state adjusting means. The larger the target fuel supply amount, the more the number of combustion burner parts. The turndown ratio can be increased by switching the number of combustion burner parts to a plurality of stages so as to increase the number of combustion burners.
Further, the combustion state detection means is provided so as to be positioned in the flame formed in the burner portion, and based on the output information of the combustion state detection means, it is determined whether or not the combustion state of the burner is abnormal. If it is determined that the combustion state is abnormal, for example, processing such as extinguishing a burner is performed.
Incidentally, the combustion state detecting means is constituted by a frame rod, a thermocouple or the like.

  When the switching of the number of combustion burner parts is described, the maximum target fuel supply amount for maintaining the stage of the combustion burner part number is set to the minimum target fuel for maintaining the stage in the next stage on the increase side of the combustion burner part from that stage. By setting the fuel supply amount overlap between the maximum target fuel supply amount and the minimum target fuel supply amount by setting it larger than the supply amount, the target fuel supply amount maintains the stage of the number of combustion burner parts. When the target fuel supply amount becomes smaller than the minimum target fuel supply amount, the number of combustion burner parts is lowered by one stage, and when the target fuel supply amount becomes larger than the maximum target fuel supply amount for maintaining the stage of the combustion burner part number, the combustion burner part number is increased by one stage. Thus, chattering in which the number of combustion burner parts is frequently switched is suppressed by switching the number of combustion burner parts.

  In such a combustion apparatus, as a conventional example related to switching of the number of combustion burner parts, the control means provides an overlap part in the control of the fuel supply state adjusting means so that the width thereof is constant, and switches the number of combustion burner parts. (For example, refer to Patent Document 1).

  In such a combustion apparatus, as a conventional example for determining whether or not the combustion state of the burner is abnormal, the abnormality determination set value in the output information of the combustion state detection means for determining the abnormality of the combustion state is the combustion Set for each target fuel supply amount for each of the plurality of stages of the burner copies, and the control means selects a set value for abnormality determination that corresponds to the current target fuel supply amount that is the stage of the current number of burner copies. Based on the selected abnormality determination setting value, it is configured to determine whether or not the combustion state of the burner is abnormal (see, for example, Patent Document 2).

  That is, even if the target fuel supply amount is the same, if the number of combustion burner parts is different, the flame size is different and the flame temperature is different, and even if the combustion burner part number is the same, the target fuel supply amount is If different, the flame size is different and the flame temperature is different, so as described above, the abnormality determination set value is set for each target fuel supply amount for each of the plurality of stages of the number of combustion burners, Whether or not the combustion state of the burner is abnormal is determined on the basis of the stage of the current number of burner units and the abnormality determination setting value adapted to the current target fuel supply amount.

JP 2003-14297 A Japanese Patent Laid-Open No. 9-126449

By the way, since the combustion state detection means is provided so as to be positioned in the flame formed in the burner portion, the larger the size of the flame in the normal combustion state of the burner portion, the higher the output. It has a characteristic that the size of information is increased.
For example, in the case where the combustion state detection means is configured by the frame rod, it is considered that the larger the flame is, the larger the area of the frame rod that contacts the flame is, so that the output information (specifically, the current value) increases. .
And the larger the output information of the combustion state detection means, the greater the degree of change in the output information when the combustion state of the burner part changes from the normal state to the abnormal state, so that the abnormality of the combustion state can be accurately discriminated. Therefore, the larger the flame, the higher the accuracy of determining the abnormality of the combustion state based on the output information of the combustion state detection means.

  However, in the conventional combustion apparatus, since the overlap portion is provided so as to have a constant width, it is necessary to increase the width of the overlap portion in order to appropriately suppress chattering in switching the number of combustion burner portions. If the target fuel supply amount approaches the minimum target fuel supply amount that maintains the stage of the number of combustion burners, it is necessary to set the minimum target fuel supply quantity that maintains the stage of the number of combustion burners. When the flame formed in the burner part becomes considerably small and the flame formed in the burner part becomes small, the degree of change in the output information when the combustion state changes from the normal state to the abnormal state becomes small. Even if the set value for abnormality determination is set for each target fuel supply amount for each of the plurality of stages of the number of combustion burners, the accuracy of determining abnormality in the combustion state is high. It was then hardly.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a combustion apparatus that can further suppress the chattering in switching the number of combustion burner parts and can further increase the accuracy of determining an abnormality in the combustion state. There is to do.

The combustion apparatus of the present invention includes a burner having a plurality of burner parts,
Fuel supply state adjusting means for switching the number of combustion burner portions to be in a fuel supply state in the plurality of burner portions to a plurality of stages and adjusting the fuel supply amount to the combustion burner portion;
A combustion state detecting means provided to be located in a flame formed in the burner portion, and outputting information according to the combustion state of the burner portion;
Whether or not the burner combustion state is abnormal based on combustion adjustment control for controlling the fuel supply state adjusting means by obtaining a target fuel supply amount corresponding to the combustion load and output information of the combustion state detecting means And a control means for performing combustion state determination control for determining
In the control of the fuel supply state adjustment means, the control means increases the number of combustion burner parts as the target fuel supply amount increases, and maintains the stage in switching the number of combustion burner parts. The maximum target fuel supply amount and the minimum target fuel supply are set by setting the fuel supply amount to be larger than the minimum target fuel supply amount for maintaining the stage in the next stage on the side where the number of combustion burner parts is increased from that stage. An overlap portion of the fuel supply amount is provided between the amount and the combustion burner number is switched,
In the first characteristic configuration, the control means changes the width of the overlap part in the control of the fuel supply state adjustment means, and the minimum target fuel supply amount that maintains the stage in switching the number of the combustion burner parts. It is in the point which is comprised so that it can be changed in size with a form.

That is, the control means reduces the width of the overlap part in a form that increases the minimum target fuel supply amount that maintains the stage in switching the number of combustion burner parts, and burns the burner while switching the number of combustion burner parts, Since the width of the overlap portion can be increased by reducing the minimum target fuel supply amount, the operation state can be switched to the state where the burner is burned while switching the number of combustion burner portions. In the operating state in which the combustion burner part number is reduced and switched, the target for switching the combustion burner part stage to the next stage on the combustion burner part reduction side is larger than in the operating state in which the overlap part is enlarged and the combustion burner part number is switched. The amount of fuel supply can be increased.
In other words, if the operation state is such that the width of the overlap part is reduced and the number of combustion burner parts is switched, even if the target fuel supply amount becomes the minimum target fuel supply amount or is close to the minimum target fuel supply amount, the largest possible flame is Since the output information of the combustion state detection means when the combustion state is normal can be increased as much as possible, it is possible that the combustion state changes from the normal state to the abnormal state. The degree of change in output information can be increased, and the accuracy of determining an abnormality in the combustion state can be further increased.

Normally, the operation of switching the number of combustion burner parts by increasing the width of the overlap part, and switching the number of combustion burner parts in a state where chattering is sufficiently suppressed, the abnormality of the combustion state is as accurate as before. If necessary, reduce the width of the overlap part and switch the number of combustion burner parts to suppress the chattering in switching the number of combustion burner parts. By making it possible to discriminate with accuracy, it is possible to make it possible to discriminate abnormalities in the combustion state with even higher accuracy while avoiding as much influence as possible in suppressing chattering in switching the number of combustion burner parts.
By the way, the control means automatically selects the operation state in which the width of the overlap part is increased and the combustion burner part number is switched to the operation state or the overlap part is reduced and the combustion burner part number is switched to the operation state. You may make it perform, and you may make it carry out artificially.
Accordingly, it is possible to provide a combustion apparatus that can further increase the accuracy of determining an abnormality in the combustion state while appropriately suppressing chattering in switching the number of combustion burner parts.

In addition to the first feature configuration, the second feature configuration is
When the normal operation condition for increasing the width of the overlap portion is satisfied, the control means increases the width of the overlap portion and decreases the width of the overlap portion. When the above is satisfied, the width of the overlap portion is reduced.

That is, when the normal operation condition for increasing the width of the overlap portion is satisfied, the control means increases the width of the overlap portion and satisfies the abnormality detection operation condition for reducing the width of the overlap portion. Reduce the width of the overlap part.
In other words, the control means automatically selects whether to set the operation state in which the width of the overlap portion is increased to switch the number of combustion burner parts or the operation state in which the width of the overlap portion is decreased to switch the number of combustion burner parts. As a result, usability can be improved.

The third feature configuration is in addition to the second feature configuration,
The burner is provided to heat a hot water supply heat exchanger that can be switched between a hot water filling state for supplying hot water to a bathtub and a general hot water supply state for supplying hot water to a hot water consumption point other than the bathtub,
The control means assumes that the normal operation condition is satisfied in the general hot water supply state, the width of the overlap portion is increased, and the abnormality detection operation condition is satisfied in the hot water filling state. The overlap portion is configured to have a small width.

  That is, when general hot water is supplied to a hot water consumption point other than the bathtub, such as a hot water tap, the control means increases the width of the overlap portion so that the normal operation condition is satisfied, and the hot water is supplied to the bathtub. Then, the control means reduces the width of the overlap portion, assuming that the abnormality detection operation condition is satisfied.

In other words, in general hot water supply, the amount of hot water supply or hot water supply temperature is arbitrarily adjusted by the user through the operation of a hot water tap, hot water mixing tap, etc. Since the target fuel supply amount is likely to change with changes, it is easy to switch the number of combustion burner parts. Supplying or supplying a set amount of hot water at a hot water filling target temperature makes it difficult for the combustion load to change and the target fuel supply amount to hardly change. Therefore, it is difficult to switch the number of combustion burners.
Therefore, in the general hot water supply state where the target fuel supply amount is likely to change and the number of combustion burner parts is easily switched, the operation is performed so as to switch the combustion burner part number by increasing the width of the overlap part. In hot water conditions where the amount is difficult to change and the number of combustion burner parts is difficult to switch, chattering is further suppressed by switching to the combustion burner part number by reducing the width of the overlap part. In this state, the combustion burner number can be switched, and an abnormality in the combustion state can be determined with higher accuracy.
Therefore, it is possible to further increase the accuracy of determining an abnormality in the combustion state while further suppressing chattering in switching the number of combustion burner parts.

Hereinafter, based on the drawings, an embodiment when the combustion device according to the present invention is applied to a hot water supply device will be described.
As shown in FIG. 1, this hot water supply apparatus is a hot water supply unit K that heats supplied water to supply hot water to a hot water tap 1 or a bathtub (not shown), and control as control means for controlling the operation of the hot water supply unit K. A part H, a remote controller operating part R for instructing the control part H to operate information, and the like are provided.

  The hot water supply section K includes a hot water supply heat exchanger 3 for water heating, a gas combustion type gas burner 4 for heating the hot water supply heat exchanger 3, and a gas burner 4 for combustion from below in the combustion chamber 2. A water supply passage 6 for supplying air from, for example, a domestic water supply to the hot water supply heat exchanger 3 is configured to include a combustion fan 5 and the like that allow air to flow and change and adjust the flow rate. Hot water supply passages 7 for sending hot water after heating are connected to each other, and the hot water tap 1 is connected to the tip of the hot water supply passage 7.

The water supply path 6 is provided with a water supply temperature thermistor 8 for detecting the temperature of water supplied to the hot water supply heat exchanger 3 and a water supply amount sensor 9 for detecting the amount of water supplied to the hot water supply heat exchanger 3. A location downstream of the hot water supply temperature thermistor 8 and the water supply amount sensor 9 in the passage 6 and the hot water supply passage 7 are connected by a water supply bypass passage 10 so as to bypass the hot water supply heat exchanger 3.
A mixing valve 11 for adjusting a mixing ratio of hot water from the hot water supply heat exchanger 3 and water from the hot water supply bypass passage 10 is provided at a connection point between the hot water supply passage 7 and the hot water supply bypass passage 10. A hot water temperature thermistor 12 for detecting the temperature of hot water sent from the hot water supply heat exchanger 3 is provided upstream of the connection location of the water supply bypass passage 10 in the passage 7, and the water supply bypass in the hot water supply passage 7 is provided. A hot water temperature thermistor 13 for detecting the temperature of the hot water after being mixed by the mixing valve 11 is provided downstream of the connection location of the passage 10.

A hot water supply hot water supply passage 14 for supplying hot water from the hot water supply heat exchanger 3 to the bathtub is branched from a location downstream of the hot water supply temperature thermistor 13 in the hot water supply passage 7. A hot water supply valve 15 for intermittently supplying hot water to the bathtub is provided in the hot water supply passage 14 for tension.
That is, the hot water supply heat exchanger 3 is configured to be switchable between a hot water filling state for supplying hot water to the bathtub and a general hot water supply state for supplying hot water to places other than the bathtub.

The gas burner 4 includes three burner portions, a first burner portion 4a, a second burner portion 4b, and a third burner portion 4c, and a fuel supply passage 16 for supplying gas fuel has three branch passages 16a, 16b, An electromagnetically operated type that branches into 16c, is connected to three burners 16a, 16b, and 16c separately to the three burner sections 4a, 4b, and 4c, and intermittently supplies gas fuel to the respective branches 16a, 16b, and 16c. Switching valves 17a, 17b, and 17c are provided, and the number of combustion burner portions that are brought into a fuel supply state by switching these switching valves 17a, 17b, and 17c can be switched to three stages.
That is, by switching the three switching valves 17a, 17b, and 17c, gas fuel is supplied only to the first burner portion 4a and only the first burner portion 4a is combusted, and the first burner portion 4a and the second burner portion. The gas fuel is supplied to 4b to burn the first burner part 4a and the second burner part 4b, and the gas is supplied to all the burner parts of the first burner part 4a, the second burner part 4b and the third burner part 4c. The number of combustion burner parts can be switched to three stages, in which fuel is supplied to burn all the burner parts of the first burner part 4a, the second burner part 4b, and the third burner part 4c. ing.

,
An electromagnetically operated gas amount adjusting valve 18 and a gas burner 4 that can change and adjust the amount of fuel supplied to the gas burner 4 are provided upstream of the branch points 16a, 16b, and 16c in the fuel supply passage 16. An electromagnetically operated intermittent valve 19 for intermittently supplying the fuel to the fuel is provided, and the switching valve 17a, 17b, 17c and the gas amount adjusting valve 18 constitute a fuel supply state adjusting means N.

  The combustion fan 5 is provided so as to supply combustion air to all of the three burner portions 4a, 4b, 4c.

The first burner portion 4a becomes a combustion burner portion to which gaseous fuel is supplied, regardless of the number of stages of the combustion burner portions.
Therefore, a frame rod 22a constituting a flame rod sensor 22 as a combustion state detecting means is provided so as to be positioned in the flame formed by the first burner portion 4a, and also near the first burner portion 4a. Is provided with an igniter 23 for executing an ignition operation.

The frame rod sensor 22 will be described further. As shown in FIG. 2, the frame rod 22a has a longitudinal direction along a direction perpendicular to the formation direction of the flame F formed by the first burner portion 4a. In this state, it is provided near the upper part of the flame outlet of the first burner portion 4a.
Although not shown in the drawings, the frame rod sensor 22 includes an AC power source that applies an AC voltage to the frame rod 22a and the first burner portion 4a, and a flame F that is formed by the first burner portion 4a. And a first detector for detecting a current flowing through a closed loop formed by the first burner portion 4a (hereinafter sometimes referred to as a frame rod current).
The flame rod current becomes smaller as the amount of combustion air becomes smaller than the proper amount, and the combustion reaction of the flame F decreases, and the temperature of the flame F decreases as the combustion reaction of the flame F decreases. As shown in FIG. 3, the flame rod current and the temperature of the flame F have a relative relationship that the flame rod current becomes smaller as the temperature of the flame F becomes lower. The flame rod current depends on the temperature of the flame F. Corresponds to the information output.
Also, there is a relative relationship between the flame rod current and the oxygen concentration of the flame F, and the flame rod current becomes smaller as the oxygen concentration of the flame F becomes lower. The flame rod current is output according to the oxygen concentration of the flame F. It corresponds to information to be done. That is, the flame rod current corresponds to information corresponding to the combustion state of the burner portion 4a.
And, as the amount of combustion air becomes smaller than the appropriate amount, the temperature and oxygen concentration of the flame F decrease and the flame rod current becomes smaller, so that the combustion state of the first burner part 4a is based on the flame rod current. It is possible to determine whether or not the combustion condition of the gas burner 4 is an oxygen deficiency abnormality, that is, an abnormality in the flame rod current for determining the oxygen deficiency abnormality. A set value for determination is set.

In the state where the amount of combustion air is appropriate and the combustion of the first burner part 4a is normal, the gas fuel is supplied to the first burner part 4a as shown by the broken line, the alternate long and short dash line and the solid line in FIG. When the amount of the flame F is different and the amount of the flame F is different, the flame contact area of the frame rod 22a is changed so as to increase as the size of the flame F increases. Therefore, in the state where the combustion of the first burner portion 4a is normal The flame rod current increases as the size of the flame F increases.
In other words, the larger the size of the flame F in the normal combustion state, the larger the amount of reduction in the flame rod current that accompanies the decrease in the amount of combustion air than the appropriate amount. The larger the value, the higher the accuracy of determining an oxygen deficiency abnormality.

  As shown in FIG. 1, the remote control operation unit R includes an operation switch 31 for instructing start / stop of operation of the hot water supply unit K, and hot water for supplying hot water at a hot water filling target temperature to the bathtub so as to reach the hot water filling target water level. Hot water filling switch 32 for commanding the hot water operation, hot water supply temperature setting switch 33 for changing and setting the hot water target temperature, hot water temperature setting switch 34 for changing and changing the hot water target temperature, and water level for changing and setting the hot water target water level A setting switch 35, a display unit 36 for displaying a hot water supply target temperature, a hot water filling target temperature, and the like, an operation lamp 37 for displaying the operation state, a combustion lamp 38 for displaying that the gas burner 4 is in a combustion state, and a gas burner 4 An alarm lamp 39 for displaying that the combustion state is abnormal is provided.

The control unit H is configured to include a microcomputer, obtains a target fuel supply amount of the gas burner 4 required to make hot water heated by the gas burner 4 to a hot water supply target temperature, and sets the target fuel supply amount to the target fuel supply amount. The fuel supply state adjusting means N is controlled so that the air flow rate of the combustion fan 5 is controlled so that the target air flow rate is set in accordance with the target fuel supply amount supplied to the combustion burner section. It is configured to execute hot water supply control as combustion adjustment control.
The control unit H is configured to execute combustion state determination control for determining whether or not the combustion state of the gas burner 4 is abnormal based on the frame rod current detected by the frame rod sensor 22. ing.

The hot water supply control executes the following processing. That is, when the hot-water tap 1 is opened and the detected value of the water flow rate detected by the water-supply amount sensor 9 exceeds the set amount with the hot-water supply section K set to the operating state, The hot water supply control is executed.
In this hot water supply control for general hot water supply, when the start of water flow to the hot water supply heat exchanger 3 is detected, an ignition process is executed to burn the gas burner 4. Then, each of the water supply amount sensor 9 and the water supply temperature thermistor 8 is from the start of hot water supply until a set time (for example, about 20 seconds) at which the hot water supply temperature is considered to be substantially stable elapses. And the target of the burner 4 necessary for setting the temperature of the hot water supplied through the hot water supply passage 7 to the hot water supply temperature based on the detected information of the hot water and the information of the hot water supply temperature set by the hot water supply temperature setting switch 33 The fuel supply amount is calculated and the number of burner parts to be burned and the fuel supply amount supplied to the combustion burner part are controlled so that the calculated target fuel supply amount is obtained, and the target fuel supply amount is set. Combustion control is executed in a so-called feed-forward (FF) control format in which the ventilation rate of the combustion fan 5 is controlled so as to achieve a target ventilation rate that is set correspondingly. Thereafter, after the set time has elapsed from the start of hot water supply, the target fuel supply amount of the gas burner 4 is obtained by calculation so that the hot water temperature detected by the hot water temperature thermistor 13 becomes the hot water supply target temperature, and the obtained target fuel supply is obtained. The mixing valve 11 controls the number of burner sections to be burned so as to reach an amount and the amount of fuel supplied to the combustion burner section, and the hot water temperature detected by the hot water temperature thermistor 13 becomes the hot water target temperature. Combustion control in a so-called feedback (FB) control format, in which the air flow rate of the combustion fan 5 is controlled so that the air flow rate of the combustion fan 5 is adjusted to the target air flow rate set in accordance with the target fuel supply amount. Execute.
Then, as the hot-water tap 1 is closed and the flow of water to the hot-water supply heat exchanger 3 is stopped, a stop process is executed to control the combustion of the burner 4 to stop.

In the ignition process, ventilation operation by the combustion fan 5 is started, and the intermittent valve 19, the switching valves 17 a, 17 b, 17 c, and the gas amount adjusting valve 18 are each adjusted to open and the igniter 23 is operated. When the gas burner 4 is ignited and ignition is confirmed by the frame rod sensor 22, the operation of the igniter 23 is stopped.
In the stop processing, each of the switching valves 17a, 17b, 17c, the gas amount adjusting valve 18, and the intermittent valve 19 is closed to stop the combustion of the gas burner 4, and the combustion fan 5 is operated after the set time has elapsed. Stop.

Further, when a hot water filling operation is commanded by the hot water filling switch 32, the hot water filling valve 15 is opened, and accordingly, the detected value of the water flow rate detected by the water supply amount sensor 9 exceeds the set amount. Thus, hot water supply control for hot water filling is executed.
In this hot water supply hot water supply control, similar to the above-described hot water supply control for general hot water supply, when the start of water flow to the hot water supply heat exchanger 3 is detected, an ignition process is executed to burn the burner 4 and Based on the information of the hot water filling target temperature set by the temperature setting switch 34, combustion control in the feed forward (FF) control format and combustion in the feedback (FB) control format similar to the hot water supply control for general hot water supply When the water level of the bathtub detected by a water level sensor (not shown) that executes control and detects the water level of the bathtub reaches the hot water target level set by the hot water level setting switch 35, the hot water valve 15 is turned on. Control is performed so that the combustion of the burner 4 is stopped by executing a stop process, similar to the hot water supply control for general hot water supply, as the water supply to the hot water supply heat exchanger 3 is stopped along with the valve closing. Configured to That.

  In the control of the fuel supply state adjusting means N, that is, the hot water supply control, the control unit H increases the number of combustion burner parts as the target fuel supply amount increases and switches the number of combustion burner parts. Is set to be larger than the minimum target fuel supply amount for maintaining the stage in the next stage on the side where the number of combustion burner parts is increased. An overlap portion of the fuel supply amount is provided between the minimum target fuel supply amount and the number of combustion burner parts is switched.

In the present invention, the control unit H controls the fuel supply state adjusting means N, that is, the width of the overlap portion in the hot water supply control is the minimum for maintaining the stage in switching the number of combustion burner units. The configuration is such that the target fuel supply amount can be changed in a large or small form.
Further, when the normal operation condition for increasing the width of the overlap portion is satisfied, the control unit H increases the width of the overlap portion and decreases the width of the overlap portion. When the operational conditions are satisfied, the width of the overlap portion is reduced.
In this embodiment, in the general hot water supply state in which the control unit H executes the hot water supply control for the general hot water supply, it is assumed that the normal operation condition is satisfied, and the width of the overlap portion is increased, and the hot water is supplied. In the hot water filling state in which the hot water supply control for tensioning is executed, the width of the overlap portion is configured to be small assuming that the abnormality detection operation condition is satisfied.

Hereinafter, the control of the gas burner 4 and the combustion fan 5 in the hot water supply control will be specifically described.
As shown in FIG. 4, the relationship between the target fuel supply amount IP and the target rotational speed of the combustion fan 5 when the number of burner sections to be burned is switched with respect to the target fuel supply amount IP is preset and stored. The hot water supply control is executed based on the stored information.
That is, based on the target fuel supply amount IP obtained by the calculation, when the target fuel supply amount IP is small, the branch path 16a connected to the first burner portion 4a extends along the small input line L1. Only the switching valve 17a is opened to adjust the opening of the gas amount adjusting valve 18, and the rotational speed of the combustion fan 5 is controlled to burn the first burner portion 4a. When the target fuel supply amount IP is large, all three switching valves 17a, 17b, and 17c are opened to adjust the opening of the gas amount adjusting valve 18 along the large input line L3. In addition, the rotational speed of the combustion fan 5 is controlled to burn all the first, second and third burner portions 4a, 4b and 4c. Further, when the target fuel supply amount IP is intermediate, the branch connected to the switching valve 17a of the branch path 16a connected to the first burner part 4a and the second burner part 4b along the middle input line L2. The switching valve 17b of the passage 16b is opened to adjust the opening of the gas amount adjusting valve 18, and the rotational speed of the combustion fan 5 is also controlled to burn the first burner portion 4a and the second burner portion 4b.

  The form in which the overlap part is provided and the form in which the width of the overlap part is changed to a larger or smaller value will be described in detail with reference to FIG. 4. The normal target fuel supply amount for maintaining the large input line L3 The minimum target fuel supply amount L3min and the abnormality detection minimum target fuel supply amount L3min ′ larger than the normal minimum target fuel supply amount L3min are set, and the maximum target fuel supply amount L2max for maintaining the middle input line L2 is set to the normal The normal overlap portion between the maximum target fuel supply amount L2max and the normal minimum target fuel supply amount L3min by making it larger than the minimum target fuel supply amount L3min and the minimum target fuel supply amount L3min ′ for abnormality detection The maximum target fuel supply amount L2max and the abnormality detection minimum target fuel supply amount L3 Between the in ', and be provided with a width smaller abnormality detection overlap portion than for normal overlap portion.

  Similarly, the normal minimum target fuel supply amount L2min as the minimum target fuel supply amount for maintaining the middle input line L2 and the abnormality detection minimum target fuel supply amount L2min ′ larger than the normal minimum target fuel supply amount L2min are set. The maximum target fuel supply amount L1max that is set and maintains the small input line L1 is made larger than the minimum target fuel supply amount L2min for normal use and the minimum target fuel supply amount L2min ′ for abnormality detection. A normal overlap portion is provided between L1max and the normal minimum target fuel supply amount L2min, and a normal overlap portion is provided between the maximum target fuel supply amount L1max and the abnormality detection minimum target fuel supply amount L2min ′. An abnormality detection overlap portion having a smaller width than that is provided.

  In the hot water supply control for the general hot water supply, the control unit H assumes that the normal operation condition is satisfied, and between the small input line L1 and the medium input line L2, and between the medium input line L2 and the large input line L3. By providing the normal overlap portion in the meantime, it is configured to increase the width of the overlap portion and switch the number of combustion burner portions. In the hot water supply control for hot water filling, the abnormality detection operation condition Is provided between the small input line L1 and the middle input line L2 and between the middle input line L2 and the large input line L3, thereby providing the width of the overlap part. And the number of combustion burner parts is switched.

Based on FIG. 4, switching of the number of combustion burner parts in the hot water supply control for general hot water supply will be described.
First, switching to the reduction side of the number of combustion burner parts will be described. All three switching valves 17a, 17b, 17c are opened, and all the first, second, and third burner parts 4a, 4b, 4c are opened. The target fuel supply amount IP maintains the large input line L3 in a state where the opening of the gas amount control valve 18 is adjusted to adjust the target fuel supply amount IP based on the large input line L3. When smaller than the normal minimum target fuel supply amount L3min, the switching valve 17c of the branch path 16c connected to the third burner portion 4c is closed to burn the first and second burner portions 4a and 4b. As the state to be made, the opening degree of the gas amount adjusting valve 18 is adjusted to adjust the target fuel supply amount IP based on the middle input line L2.
Further, the switching valve 17a of the branch path 16a connected to the first burner section 4a and the switching valve 17b of the branch path 16b connected to the second burner section 4b are opened, and the first and second two burners are opened. When the opening of the gas amount adjusting valve 18 is adjusted to adjust the target fuel supply amount IP based on the middle input line L2 by burning the parts 4a and 4b, the target fuel supply amount IP is equal to the middle input line. When smaller than the normal minimum target fuel supply amount L2min for maintaining L2, the switching valve 17b of the branch path 16b connected to the second burner portion 4b is closed, and only the first burner portion 4a is burned. The opening of the gas amount adjusting valve 18 is adjusted to adjust the target fuel supply amount IP based on the small input line L1.

Hereinafter, switching to the increasing side will be described. Based on the small input line L1, only the switching valve 17a of the branch path 16a connected to the first burner portion 4a is opened and only the first burner portion 4a is burned. When the target fuel supply amount IP exceeds the maximum target fuel supply amount L1max for maintaining the small input line L1 in a state where the opening amount of the gas amount adjusting valve 18 is adjusted to adjust the target fuel supply amount IP, further Then, the switching valve 17b of the branch path 16b connected to the second burner part 4b is opened, and the first and second burner parts 4a and 4b are in a state of burning based on the middle input line L2. The opening amount of the gas amount adjusting valve 18 is adjusted to adjust the fuel supply amount IP.
Further, the switching valve 17a of the branch path 16a connected to the first burner section 4a and the switching valve 17b of the branch path 16b connected to the second burner section 4b are opened, and the first and second two burners are opened. When the opening of the gas amount adjusting valve 18 is adjusted to adjust the target fuel supply amount IP based on the middle input line L2 by burning the parts 4a and 4b, the target fuel supply amount IP is equal to the middle input line. When the maximum target fuel supply amount L2max that maintains L2 is exceeded, the switching valve 17c of the branch passage 16c connected to the third burner portion 4c is further opened, and all the first, second, and third burners are opened. As the state in which the parts 4a, 4b, 4c are burned, the opening of the gas amount adjusting valve 18 is adjusted to adjust the target fuel supply amount IP based on the large input line L3.

Next, switching of the number of combustion burner parts in the hot water supply control for hot water filling will be described with reference to FIG.
Explaining the switching to the reduction side of the number of combustion burner parts, all three switching valves 17a, 17b, 17c are opened, and all the first, second and third burner parts 4a, 4b, 4c are combusted. Thus, in the state where the opening degree of the gas amount adjusting valve 18 is adjusted to adjust the target fuel supply amount IP based on the large input line L3, the abnormality detection that the target fuel supply amount IP maintains the large input line L3 is detected. When it becomes smaller than the minimum target fuel supply amount L3min ′, the switching valve 17c of the branch path 16c connected to the third burner portion 4c is closed, and the first and second burner portions 4a and 4b are combusted. As the state to be made, the opening degree of the gas amount adjusting valve 18 is adjusted to adjust the target fuel supply amount IP based on the middle input line L2.
Further, the switching valve 17a of the branch path 16a connected to the first burner section 4a and the switching valve 17b of the branch path 16b connected to the second burner section 4b are opened, and the first and second two burners are opened. When the opening of the gas amount adjusting valve 18 is adjusted to adjust the target fuel supply amount IP based on the middle input line L2 by burning the parts 4a and 4b, the target fuel supply amount IP is equal to the middle input line. When it becomes smaller than the abnormality detection minimum target fuel supply amount L2min ′ that maintains L2, the switching valve 17b of the branch path 16b connected to the second burner portion 4b is closed, and only the first burner portion 4a is burned. As a state, the opening degree of the gas amount adjusting valve 18 is adjusted to adjust the target fuel supply amount IP based on the small input line L1.

  Note that switching to the increase side of the number of combustion burner parts in the hot water supply control for hot water filling is the same as switching to the decrease side of the number of combustion burner parts in the hot water supply control for general hot water supply described above, and therefore description thereof is omitted.

Next, the combustion state determination control will be described.
In hot water supply control for general hot water supply or hot water filling, when the number of combustion burner parts is the same, the larger the target fuel supply amount IP, the larger the flame and the higher the temperature and oxygen concentration of the flame. Even if the supply amount IP is the same, if the number of combustion burner parts decreases, the flame increases and the flame temperature and oxygen concentration increase.
For example, if the target fuel supply amount IP is the same, in the state where one burner portion of the first burner portion 4a is burned based on the small input line L1, the first and second 2 are based on the middle input line L2. The flame becomes larger than the state in which the two burner portions 4a and 4b are burned and the temperature and oxygen concentration of the flame are increased, and the first and second burner portions 4a and 4b are burned based on the middle input line L2. In the state, if the target fuel supply amount IP is the same, the flame becomes larger than the state in which the first, second and third three burner portions 4a, 4b and 4c are burned based on the large input line L3. Increases flame temperature and oxygen concentration.

  Therefore, in advance, for each of the small input line L1, the medium input line L2, and the large input line L3, the abnormality determination setting value is set according to the target fuel supply amount IP under the condition that the larger the target fuel supply amount IP is. A plurality of settings are set and stored in the control unit H.

The control unit H performs hot water supply control based on any of the input lines L1, L2, and L3 based on the open / close operation states of the three switching valves 17a, 17b, and 17c in each of the hot water supply controls for general hot water supply and hot water filling. Among the plurality of abnormality determination setting values set for the determined input lines L1, L2, and L3, the abnormality determination setting value corresponding to the current target fuel supply amount IP. Is selected, and when the frame rod current detected by the frame rod sensor 22 is smaller than the selected abnormality determination setting value, it is determined that an oxygen deficiency abnormality is present.
And if the said control part H discriminate | determines that it is an oxygen deficiency abnormality, the said stop process will be performed, the combustion of the gas burner 4 will be stopped, and the said alarm lamp 39 will be lighted.

  In the hot water supply control for hot water filling, the width of the overlap portion in the control of the fuel supply state adjusting means N is reduced in such a manner that the minimum target fuel supply amount is set larger than in the hot water supply control for general hot water supply. In hot water supply control for hot water filling, even when the target fuel supply amount becomes the minimum target fuel supply amount or close to the minimum target fuel supply amount, a flame that is as large as possible can be formed and burned. Since the flame rod current output from the flame rod sensor 22 in the normal state can be increased as much as possible, the degree of change in the output information when the combustion state changes from the normal state to the abnormal state is increased. This increases the accuracy of determining the abnormality of the combustion state.

[Another embodiment]
Next, another embodiment will be described.
(A) In the above embodiment, the case where the control unit H is configured to automatically select whether to increase or decrease the width of the overlap portion is described. It is also possible to provide an artificially operated switching means for switching between a state of increasing and a state of decreasing to artificially select whether the width of the overlap portion is increased or decreased.

(B) The specific conditions of the normal operation condition and the abnormality detection operation condition are not limited to the conditions exemplified in the above embodiment.
For example, every time the set period elapses, every time the accumulated combustion amount of the burner 4 becomes a set amount, or every time the number of ignition times of the gas burner 4 becomes a set number of times, the abnormality detection operation condition is satisfied. You may comprise so that normal driving | running conditions may be satisfy | filled.

(C) In the above embodiment, the combustion fan 5 is configured so that the combustion air is supplied to all the burner parts constituting the gas burner 4 so that the burner part to which no gas fuel is supplied is also used for combustion. The case where it is configured to be supplied with air is exemplified, but the configuration is such that the ventilation path can be switched and the supply amount can be adjusted so as to supply the combustion air only to the burner section to which the gas fuel is supplied. Combustion air supply means may be provided.
In this case, since the combustion air is not supplied to the burner portion to which no gaseous fuel is supplied, the relative relationship between the target fuel supply amount IP and the target rotational speed of the combustion fan 5 is set across a plurality of stages of the number of combustion burner portions. It can be set with one continuous line.
For example, when the number of combustion burner parts is switched to three stages, as shown in FIG. 5, the small input line L1, the medium input line L2, and the large input line L3 can be set by one continuous line.
Also in this case, as shown in FIG. 5, as shown in FIG. 5, the normal minimum target fuel supply amounts L3min and L2min are used as the minimum target fuel supply amounts for maintaining the large and medium input lines L3 and L2. The abnormality detection minimum target fuel supply amounts L3min ′ and L2min ′ are set larger than the normal overlap part and the abnormality detection overlap part having a smaller width than the normal overlap part. .

(D) The specific configuration of the combustion state detection means is not limited to the case of being configured with the frame rod 22a as illustrated in the above embodiment, and may be configured with a thermocouple, for example. .

(E) The number of stages of the number of combustion burner parts is not limited to the three stages exemplified in the above embodiment, and may be two stages or four or more stages.

(F) In the above-described embodiment, the case where the specific configuration of the combustion apparatus to which the present invention is applied is a hot water supply apparatus that supplies hot water to a bathtub or a hot water tap, but the specific configuration of the combustion apparatus to which the present invention is applied is various. It can be changed.
For example, in addition to a hot water supply heat exchanger, a heat exchanger for heating that heats hot water circulated through a bathtub circulation path, or a heating heat exchanger that heats a heating heat medium circulated through a heating circulation path It may be provided with.

Block diagram showing the overall configuration of the water heater Diagram showing the installation state of the frame rod Diagram showing the relationship between flame rod current and flame temperature Diagram showing the relationship between the target fuel supply amount and the target rotational speed of the combustion fan The figure which shows the relationship between the target fuel supply amount which concerns on another embodiment, and the target rotational speed of the fan for combustion

Explanation of symbols

2 Hot water supply heat exchanger 4 Burner 4a, 4b, 4c Burner part 22 Combustion state detection means H Control means N Fuel supply state adjustment means

Claims (3)

A burner having a plurality of burner parts;
Fuel supply state adjusting means for switching the number of combustion burner portions to be in a fuel supply state in the plurality of burner portions to a plurality of stages and adjusting the fuel supply amount to the combustion burner portion;
A combustion state detecting means provided to be located in a flame formed in the burner portion, and outputting information according to the combustion state of the burner portion;
Whether or not the burner combustion state is abnormal based on combustion adjustment control for controlling the fuel supply state adjusting means by obtaining a target fuel supply amount corresponding to the combustion load and output information of the combustion state detecting means And a control means for performing combustion state determination control for determining
In the control of the fuel supply state adjustment means, the control means increases the number of combustion burner parts as the target fuel supply amount increases, and maintains the stage in switching the number of combustion burner parts. The maximum target fuel supply amount and the minimum target fuel supply are set by setting the fuel supply amount to be larger than the minimum target fuel supply amount for maintaining the stage in the next stage on the side where the number of combustion burner parts is increased from that stage. A combustion apparatus configured to switch the number of combustion burner parts by providing an overlap part of the fuel supply amount between
The control means changes the width of the overlap portion in the control of the fuel supply state adjusting means to be larger or smaller in such a manner that the minimum target fuel supply amount for maintaining the stage in switching the number of the combustion burner portions is changed to be larger or smaller. Combustion device configured to be able to.   When the normal operation condition for increasing the width of the overlap portion is satisfied, the control means increases the width of the overlap portion and decreases the width of the overlap portion. The combustion apparatus according to claim 1, wherein when the condition is satisfied, the width of the overlap portion is reduced. The burner is provided to heat a hot water supply heat exchanger that can be switched between a hot water filling state for supplying hot water to a bathtub and a general hot water supply state for supplying hot water to a hot water consumption point other than the bathtub,
The control means assumes that the normal operation condition is satisfied in the general hot water supply state, the width of the overlap portion is increased, and the abnormality detection operation condition is satisfied in the hot water filling state. The combustion apparatus according to claim 2, wherein the width of the overlap portion is reduced.

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