JP4912326B2 - Combustion equipment - Google Patents

Description

  The present invention relates to combustion equipment.

  Conventionally, a thermocouple and a frame rod are known as means for detecting incomplete combustion. The following patent document 1 is known as a prior art in which the former thermocouple is incorporated in a combustion device, and the following patent document 2 is known as a technique in which the latter frame rod is incorporated. In both cases, the combustion operation is controlled by comparing the output value that changes depending on the combustion state with a preset threshold value.

JP-A-8-35650 Japanese Patent Laid-Open No. 10-19249

  However, it is generally known that the thermocouple used in Patent Document 1 has low responsiveness to changes in combustion conditions, and tends to cause a slight delay in detection of incomplete combustion. There is also an advantage that it does not react sensitively to the influence of disturbances. In this regard, it is pointed out that the frame rod used in Patent Document 2 has higher responsiveness than a thermocouple, but is easily affected by disturbance.

  Therefore, an object of the present invention is to provide a combustion apparatus that can detect an incomplete combustion accurately while making it difficult to be affected by disturbance as much as possible while using a frame rod having excellent responsiveness.

A combustion apparatus according to the present invention includes a pale flame outlet that ejects a relatively lean gas mixture, and a dense flame that is provided adjacent to the pale flame mouth and that emits a relatively dense gas mixture. possess a flame hole, and shading burner comprising a plurality of burners capable of selectively burning,
A flame rod that is disposed across the upper region of both the flame flame and the flame flame of the flame flame, the output value of which varies according to the combustion status of the flame burner,
A determination unit for determining whether to stop the combustion of the light and dark burner based on whether or not the output value from the frame rod is lower than a preset reference value;
The determination unit, the shading in the burner during normal combustion after a lapse of a constant time Tokoro ignited, the second to reduce the high or selecting a reference value, or lower the reference value by selecting an output value correction When the number of burners to be burned is switched in this state, a lower reference value is selected from the second process or a higher reference value is selected and output until a predetermined time elapses. It is characterized in that it can be switched to the first process for increasing the value .

  In the light and dark burner, as the amount of air increases, the rich flame set to gas rich becomes stable, and the amount of ions in the rich flame increases. For this reason, when the frame rod is disposed in the upper region of the rich flame, as shown in FIG. 5A, the output value of the frame rod increases as the air amount increases within the actual use range of the dark and light burner. On the other hand, as the amount of air decreases, the light flame set to air rich becomes stable, and the amount of ions in the light flame increases. For this reason, when the frame rod is disposed in the upper region of the light flame, as shown in FIG. 5B, the output value of the frame rod increases as the amount of air decreases within the actual usage range of the light and dark burner. Therefore, when the frame rod is disposed between the upper regions of both the rich flame and the light flame, the flame rod detects and outputs the total amount of ions in the rich flame and the light flame. As shown, the output value of the frame rod is maintained at a high value in the entire range within the actual use range of the light and dark burner. In other words, even if the air supply to the light and dark burner fluctuates due to disturbance such as wind, the output value of the frame rod is not easily affected, and a stable value is output. Can be prevented.

  When the light and dark burner is ignited, the output value of the frame rod gradually rises due to the formation of a combustion flame. On the other hand, for a while after the burner is ignited, the combustion flame is unstable and the output value is low and fluctuates. Therefore, particularly in the early stage of ignition, if there is a disturbance such as wind, the output value of the frame rod is strongly influenced and erroneous determination occurs. Therefore, in the initial stage of ignition, unless the first process is performed such that the reference value is set low or the reference value is set high and the output value of the frame rod is corrected to be increased from the actual value, There is a situation in which burner combustion stops carelessly due to erroneous determination of complete combustion.

  On the other hand, when the amount of air decreases during normal combustion and the incomplete combustion state proceeds, the output value of the frame rod gradually decreases. In such an incomplete combustion situation, the reference value set at the beginning of ignition remains low, or the reference value is set high to increase the output value of the frame rod. Otherwise, it takes time for the output value of the frame rod to fall below the reference value. On the other hand, in the present invention, during the normal combustion, the second process of switching to a high reference value or setting a low reference value and correcting the output value to decrease is performed, so that incomplete combustion is detected early. Thus, combustion can be stopped.

  Therefore, the combustion apparatus of the present invention corrects the reference value or the output value by arranging the frame rod across the upper region of both the light flame and the rich flame and performing the first process and the second process. In combination, the incomplete combustion can be detected early without erroneous determination.

  The determining unit may perform the first process on the reference value or the output value of the frame rod when the combustion of the light and dark burner is performed in a region where the gas supply amount is low during normal combustion. While combustion is performed in a region where the gas supply amount is low, the output value from the frame rod is low even during normal combustion. Therefore, in the state where the second process is performed, a situation where the combustion is inadvertently stopped may occur. However, if the first process is performed, the accidental stop of the combustion is avoided. Even if the combustion continues for a long time, the incomplete combustion does not cause a problem because of the low capacity.

The light and dark burner is composed of a plurality of burners that can be selectively burned, and when the number of burners to be burned is switched during the normal combustion, the determination unit is set to a reference value or until a predetermined time elapses. a second process on the output value of the frame rods, Ru is switched to the first processing. In this way, even when the flame immediately after the number of burners to be burned is unstable, erroneous determination due to the influence of disturbance can be made difficult to occur.

  At the time of reignition after the combustion of the light and dark burner is stopped based on the determination by the determination unit, if the predetermined time has not elapsed since the reignition is stopped, the determination unit may The second process may be performed on the value or the output value of the frame rod. It is possible that reignition is attempted immediately after the determination unit determines that incomplete combustion has occurred, and based on this, combustion of the light and dark burner is stopped. In that case, if the determination unit performs the first process, it is determined that there is a difference between the reference value and the output value of the frame rod, and the combustion state may be continued. However, if the second process is continued as it is, the determination unit makes the same determination as when the combustion is stopped, and therefore reignition after the forced stop can be prohibited.

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIGS. As shown in FIG. 1, a water heater 1 that is a combustion device of the present embodiment includes a combustion box 3 in a housing 2. The housing 2 is provided with an air intake 2A. The water heater 1 also includes a concentration burner 10, a spark plug 20 </ b> A, a frame rod 20 </ b> B, and a heat exchanger 30 inside the combustion box 3. The water heater 1 includes a combustion fan 40 connected to the lower end of the combustion box 3 and supplying combustion air to the light and dark burner 10. Furthermore, the water heater 1 includes a control device 50 that can set the gas supply amount to the light and dark burner 10 and the rotational speed of the combustion fan 40. The control device 50 includes a determination unit 51 that determines whether or not to stop the combustion of the light and dark burner 10 based on whether or not the output value from the frame rod 20B falls below a preset reference value, and a reference value. A storage unit 52 is provided.

  The light and dark burner 10 is disposed in the lower part of the combustion chamber 3 and includes a plurality of burners 11 and is divided into a first burner group 11A and a second burner group 11B. The first burner group 11A has a larger number of burners and a higher combustion capacity than the second burner group 11B. Branch gas supply paths 60A and 60B that supply gas by branching from one gas supply path 60 into two are connected to each of the burner groups 11A and 11B. The gas supply path 60 is provided with an original electromagnetic valve 61 and a gas proportional valve 62. One branch gas supply path 60A is provided with an electromagnetic valve 63A. The gas proportional valve 62 adjusts the opening degree of the gas supply path 60 and adjusts the gas supply amount to each of the burner groups 11A and 11B. In addition, by opening and closing the gas electromagnetic valve 63A, it is possible to switch between two stages: a case where both the first burner group 11A and the second burner group 11B are combusted and a case where only the second burner group 11B is combusted. . That is, the number of burners 11 to be burned can be switched.

  As shown in FIG. 2, each burner 11 is provided adjacent to the pale flame port 12 for jetting a light mixture having a relatively lean gas concentration and the pale flame port 12, and has a relatively dense gas concentration. And a rich flame outlet 13 for ejecting a rich air-fuel mixture. The flame rod 20B is disposed in the burner group 11B, and is disposed across the upper region of both the light flame 12F formed in the light flame port 12 and the heavy flame 13F formed in the heavy flame port 13. ing. For this reason, even if the air supply amount to the light and dark burner 10 fluctuates due to disturbance such as wind, the frame rod 20B detects and outputs the total amount of ions in the rich flame 13F and the light flame 12F. The output value of 20B is not easily affected, and a stable value is output. Therefore, erroneous determination of incomplete combustion can be prevented.

  As shown in FIG. 1, the heat exchanger 30 is disposed in the upper part of the combustion box 3. Water is supplied to the heat exchanger 30 through a water supply passage 71, and hot water heated by the heat exchanger 30 is discharged through a hot water supply passage 72. Connected between the water supply path 71 and the hot water supply path 72 is a bypass path 73 that branches part of the water from the water supply path 71 and joins it to the hot water supply path 72. A water supply amount sensor 74 that detects the flow rate of the water supply passage 71 is provided in the water supply passage 71.

  An operation unit 53 is connected to the control device 50. The control device 50 controls the gas proportional valve 62 and the gas electromagnetic valve 63A so that hot water at the hot water temperature (hereinafter referred to as “set temperature”) set by the operation unit 53 is discharged from the hot water supply passage 72. While setting the gas supply amount to each burner group 11A, 11B, the rotation speed of the combustion fan 40 is controlled according to the gas supply amount.

  Next, based on the flowchart shown in FIG. 3, the incomplete combustion detection operation from the start to the stop of the combustion of the light and dark burner 10 will be described.

  When a water faucet device (not shown) connected downstream of the hot water supply passage 72 is opened and the water supply amount sensor 74 detects that water of a predetermined flow rate or more has flowed through the water supply passage 71, the spark plug 20A is activated to increase or decrease the density. The burner 10 is ignited and combustion is started (S1).

When the previous combustion is determined that incomplete combustion has occurred due to a decrease in oxygen concentration in the room where the hot water heater 1 is installed as described later (S6), the concentration burner 10 is forcibly stopped (S7). After the stop, it is determined whether or not a predetermined time t ₁ (time until the oxygen concentration returns to an appropriate value, for example, 1 hour) has passed (S2). If incomplete combustion has not occurred in the past, it is considered that t ₁ time has elapsed.

When the predetermined time t ₁ has elapsed, a first process of selecting a low reference value = 0.5 μA is performed and stored in the storage unit 52 (S3). In the early stage of ignition, if there is a disturbance such as wind, the output value of the frame rod 20B is strongly affected, and the output value falls below the reference value, and it is easy to erroneously determine incomplete combustion. For this reason, the situation where the combustion of the light and dark burner 10 stops carelessly by performing the first process is avoided.

When the predetermined time t ₁ has not elapsed, a high reference value X = 5 μA is selected and stored in the storage unit 52 (S4). Immediately after it is determined that incomplete combustion has occurred (it is in an oxygen deficient state) and the user has forcibly stopped, a second process in which a high reference value is selected is performed when the user attempts to reignite. Therefore, the same judgment as when the combustion is stopped is made, and reignition is prohibited.

  Next, the control device 50 selects the combustion of the first burner group 11A in accordance with the flow rate of the water flowing in the water supply channel 71 and the set temperature, and supplies the gas proportionally so as to supply the optimum gas amount and air amount. The valve 62, the gas electromagnetic valve 63A and the combustion fan 40 are controlled (S5).

  Next, it is determined whether or not the output value from the frame rod 20B is greater than or equal to the reference value stored in the storage unit 52 (S6). At the initial stage of normal ignition, a low reference value X = 0.5 μA is selected to prevent erroneous determination. If the output value from the frame rod 20B is less than the reference value, it is determined that an ignition error or the like has occurred, and the combustion operation of the light and dark burner 10 is forcibly stopped (S7).

When the output value from the frame rod 20B is equal to or greater than the reference value, it is determined whether or not the gas supply amount to the light and dark burner 10 is equal to or greater than Y (kW / h) (for example, 5.8 kW / h) ( S8). Because the gas supply amount while the combustion takes place in a region low of less than Y (kW / h), a low output value from the flame rod 20B even during normal combustion after ignition t ₃ hours has elapsed, a low reference value X = 0.5 μA is selected and stored in the storage unit 52 (S12). Thereby, the situation of inadvertent combustion stop is avoided. Even if combustion continues for a long time, incomplete combustion is not a problem because it is under low capacity.

Next, it is determined whether t ₂ hours (for example, 30 seconds) have elapsed after switching of the burner groups 11A and 11B (S9). When t ₂ hours have not elapsed, a low reference value X = 0.5 μA is selected and stored in the storage unit 52 (S12). Immediately before and immediately after the burner groups 11A and 11B are switched and the number of burning burners 11 is switched, the air-fuel ratio is adjusted to be suitable for performing the fire transfer between the burner groups. This is because it is out of the good range and the flame is unstable, so that misjudgment due to the influence of disturbance is less likely to occur.

Next, it is determined whether t ₃ hours (for example, 60 seconds) have elapsed after the light / dark burner 10 is ignited. When t ₃ time has not elapsed, since the ignition is still in the initial stage, a low reference value X = 0.5 μA is selected (S12). On the other hand, if the time t ₃ has elapsed, a second process is performed in which a high reference value X = 5 μA is selected (S 11) and stored in the storage unit 52. As shown in FIG. 4, during normal combustion (t ₃ hours after), if, by lowering the oxygen content of the room where the water heater 1 is installed, the incomplete combustion state progresses, the output of the flame rod 20B The value gradually decreases. In this case, by performing the second process, it is possible to detect incomplete combustion earlier (Y point) in S6 compared to the time point (Z point) below the lower reference value of the first process, and the combustion It can be forcibly stopped. Thereby, combustion can be forcibly stopped at a stage where the CO concentration is low.

  Thereafter, when a normal combustion stop operation is performed by closing the faucet device, a combustion stop process (S13) is performed based on a signal from a water supply amount sensor 74 installed in the water supply channel 71. As a result, the original solenoid valve 61 is closed, and the rotation of the combustion fan 40 is stopped to stop the combustion operation (S14). When the combustion stop process is not performed, the combustion is continued.

  As described above, the water heater 1 according to the first embodiment is located between the upper regions of the light flame 12F in which the frame rod 20B is formed in the light flame port 12 and the heavy flame 13F formed in the gas flame port 13. Since the total amount of ions in the rich flame 13F and the light flame 12F is detected and output, the output value from the frame rod 20B increases over the actual usage range of the air amount, Can be less affected. Further, as shown in FIG. 4, the first process is performed at the initial stage of ignition to prevent erroneous determination, and the second process is performed at the time of normal combustion, so that incomplete combustion can be detected early and combustion can be stopped. .

  Therefore, the water heater 1 according to the first embodiment corrects the reference value by arranging the frame rod 20B across the upper region of both the light flame 12F and the rich flame 13F and performing the first process and the second process. In combination with this, incomplete combustion can be detected early without erroneous determination.

<Other embodiments>
The present invention is not limited to the first embodiment described with reference to the above description and the drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, the scope other than the following does not depart from the gist. Can be implemented with various changes

  (1) The combustion device is not limited to a water heater, but may be a heating device (gas infrared heater, gas fan heater), a bath tub, or the like.

  (2) In the first embodiment, when the first process is performed, the low reference value X = 0.5 μA is selected. However, the high reference value X = 5 μA is selected, and the output value of the frame rod 20B is increased by 4.5 μA. It may be corrected.

  (3) In the first embodiment, when the second process is performed, the high reference value X = 5 μAga is selected. However, the low reference value X = 0.5 μA is selected, and the output value of the frame rod 20B is only 4.5 μA. Decrease correction may be performed.

  (4) Also, the frame rod 20B extends in the longitudinal direction from the end of the burner in the longitudinal direction to the upper region of one of the rich flame ports 13 and then bends to obliquely cross the upper region of the pale flame port 12. You may arrange | position so that the upper area | region of the other rich flame mouth 13 may be reached.

It is the schematic which shows the water heater of Embodiment 1. FIG. It is a schematic diagram which shows the light and dark burner and frame rod of Embodiment 1. It is a flowchart which shows the detection operation of the incomplete combustion of the water heater of Embodiment 1. It is a graph which shows the relationship between the output value and CO density | concentration of a flame rod, and combustion time. It is a graph which shows the relationship between the output value of a flame rod, and air quantity.

Explanation of symbols

1 ... Hot water heater (combustion equipment)
DESCRIPTION OF SYMBOLS 10 ... Light / dark burner 11 ... Burner 12 ... Light flame outlet 13 ... Heavy flame opening 20B ... Frame rod 51 ... Determination part

Claims (4)

Relatively and light flame hole of the gas concentration is ejected pale mixture sparse, provided adjacent to a light flame hole, possess a concentrated flame hole relatively gas concentration is ejected dark rich mixture, A light and dark burner comprising a plurality of burners that can be selectively burned , and
A flame rod that is disposed across the upper region of both the flame flame and the flame flame of the flame flame, the output value of which varies according to the combustion status of the flame burner,
A determination unit for determining whether to stop the combustion of the light and dark burner based on whether or not the output value from the frame rod is lower than a preset reference value;
The determination unit, the shading in the burner during normal combustion after a lapse of a constant time Tokoro ignited, the second to reduce the high or selecting a reference value, or lower the reference value by selecting an output value correction When the number of burners to be burned is switched in this state, a lower reference value is selected from the second process or a higher reference value is selected and output until a predetermined time elapses. A combustion apparatus that is switched to a first process for increasing and correcting a value . The determination unit performs the first processing on the reference value or the output value of the frame rod in an early stage of ignition until the predetermined time elapses after the light / dark burner is ignited. Item 10. The combustion device according to Item 1. In the normal combustion, the determination unit performs the first process on the reference value or the output value of the frame rod when combustion of the light and dark burner is performed in a region where the gas supply amount is low. The combustion apparatus according to claim 1 or 2, wherein   At the time of re-ignition after the combustion of the light and dark burner is stopped based on the determination of the determination unit, the re-ignition is performed when the predetermined time has not elapsed since the stop point. The combustion apparatus according to any one of claims 1 to 3, wherein the second process is performed on the reference value or the output value of the frame rod even in an initial stage.

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