JP2005249249A - Combined combustion apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the combustion state of the other combustion part under normal combustion from being deteriorated due to excessive air when the supplied amounts of air at both combustion parts are increased. <P>SOLUTION: This combined combustion apparatus having at least two combustion parts 1 and 2 comprises a control means increasing the supplied amount of air to the combustion parts during combustion operation more than a reference air amount corresponding to the amount of combustion. The apparatus determines that the combustion state is deteriorated by the incomplete combustion of only one combustion part during the simultaneous combustion operations of both combustion parts and sets an air amount increasing coefficient for each combustion parts 1 and 2 so that the combustion state is not deteriorated due to an increase in the amount of the combustion air in a normal combustion state. When the combustion state is determined to be deteriorated, the supplied amount of the combustion air to the combustion parts 1 and 2 during the combustion operation is increased according to the set value of the air amount increasing coefficient. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a combined combustion apparatus provided with at least two combustion sections containing a burner such as a hot water supply / heating heat source machine.

  Conventionally, in this type of combined combustion apparatus, a separate blower for supplying combustion air to each combustion unit is provided, and combustion air having a reference air amount corresponding to the combustion amount of the burner is supplied to each combustion unit. I have to. In addition, when a CO sensor is arranged at the merging portion of the combustion exhaust that guides the combustion exhaust from each combustion portion to a single exhaust passage, and the CO concentration in the combustion exhaust detected by the CO sensor exceeds a predetermined value There is also known one that stops combustion in each combustion section during the combustion operation (see, for example, Patent Document 1).

  By the way, incomplete combustion due to temporary disturbances such as the discharge of combustion exhaust from the exhaust passage being hindered by the influence of outdoor wind may occur, and the CO concentration may exceed a predetermined value. Stopping the operation is inconvenient for the user.

  Here, although the combustion apparatus is provided with a single combustion section, conventionally, when the detected CO concentration of the CO sensor becomes a predetermined value or more, the supply amount of combustion air to the combustion section is increased. Is known (see, for example, Patent Document 2). According to this, when incomplete combustion due to disturbance occurs, it is highly possible that the combustion state will be improved by increasing the amount of combustion air, and the frequency of reaching the combustion stop will be low, which will inconvenience the user to the left. No need to spend.

  Therefore, even in the combined combustor, when the CO concentration in the combustion exhaust gas exceeds a predetermined value, the supply amount of combustion air to the combustion section during the combustion operation is increased so that the CO concentration becomes less than the predetermined value. It is desirable to improve the combustion state.

Here, in the combined combustion apparatus, only a part of the combustion parts may be incompletely burned during the simultaneous combustion operation of the plurality of combustion parts. However, the CO sensor disposed at the merging portion of the combustion exhaust cannot determine which combustion portion is incompletely combusted, and must increase all the supply amounts of combustion air to the plurality of combustion portions. . In this case, in the combustion part that is normally combusting, there is an excess of air, causing flames to blow out, and the combustion state may deteriorate. Therefore, even if the air supply amount is increased, the CO concentration does not decrease, and finally the combustion in each combustion section is stopped. Although it is conceivable to provide a CO sensor individually for each combustion section, this increases the cost.
Japanese Examined Patent Publication No. 4-38973 (page 3, FIG. 2, FIG. 3) JP-A-11-337060 (0014, FIG. 2)

  In view of the above points, the present invention determines the combustion state of a combustion part as a combustion part in a normal combustion state even if incomplete combustion occurs in a part of the combustion parts during simultaneous combustion operation of a plurality of combustion parts. An object of the present invention is to provide a combined combustion apparatus that can be improved without deteriorating the state.

  In order to solve the above-mentioned problems, the present invention is a combined combustion apparatus provided with at least two combustion sections with a built-in burner, each blower supplying combustion air to each combustion section, and each combustion section A CO sensor for detecting the CO concentration in the combustion exhaust disposed at the merging portion of the combustion exhaust leading the combustion exhaust from the exhaust to a single exhaust passage, and determining that the combustion state has deteriorated based on the detected CO concentration of the CO sensor And a control means for controlling the blower so that the supply amount of the combustion air to each combustion section during the combustion operation is increased from the reference air amount corresponding to the combustion amount. Air expansion coefficient set for each combustor to prevent the deterioration of the combustion state due to the increase of the combustion air in the normal combustion state, with the coefficient representing the ratio of the supply amount of combustion air to the amount as the air increase coefficient Memorize the set value Each of the combustion sections stored in the storage means for supplying the amount of combustion air supplied to each combustion section during the combustion operation when it is determined that the combustion state has deteriorated. It is configured to increase in accordance with the set value of the air increase coefficient.

  According to the above configuration, when it is determined that the combustion state has deteriorated due to incomplete combustion in some of the combustion sections during the simultaneous combustion operation of the plurality of combustion sections, the supply amount of combustion air is increased. The combustion state of the incomplete combustion state of the combustion part is improved. At this time, the combustion air supplied to the combustion section in the normal combustion state is also increased, but this increase amount is a deterioration of the combustion state due to the increase in the combustion air in the normal combustion state by setting the air increase coefficient described above. Therefore, the combustion state of the combustion part in the normal combustion state is not deteriorated. In order to improve combustion when incomplete combustion occurs, the set value of the air increase coefficient is set as large as possible within a range that does not cause deterioration of the combustion state due to an increase in combustion air in the normal combustion state. That is, it is desirable to set the upper limit of this range or a value near the upper limit.

  In addition, although the upper limit of the air increase coefficient that does not cause deterioration of the combustion state due to an increase in combustion air in the normal combustion state is not necessarily the same in all combustion parts, in the present invention, the air increase coefficient is set for each combustion part. Because it is set, there is no problem.

  When it is determined that the combustion state has deteriorated, the air increase coefficient may be increased stepwise toward the set value.

  FIG. 1 shows a hot water supply / heating heat source machine, and includes a hot water supply combustion unit 1 and a heating combustion unit 2. Each of the combustion units 1 and 2 includes a combustion casing 11 and 21, burners 12 and 22 stored in the lower part of the combustion casing 11 and 21, and heat exchangers 13 and 23 stored in the upper part of the combustion casing 11 and 21. Has been. An upstream water supply pipe 14 and a downstream hot water discharge pipe 15 are connected to the heat exchanger 13 of the hot water supply combustion section 1, and a hot water tap (not shown) at the downstream end of the hot water discharge pipe 15 is opened. When the water is passed through the heat exchanger 13, the burner 12 is ignited, and hot water at a set temperature is discharged from the hot water tap. The heat exchanger 23 of the heating combustion section 2 is connected to a heating circuit (not shown) such as floor heating via an outgoing pipe 24 and a return pipe 25, and is connected to the heating circuit via the heat exchanger 23. Circulate hot water and heat.

  Gas is supplied to the burners 12 and 22 of the combustion sections 1 and 2 via the electromagnetic on-off valves 16 and 26 and the electromagnetic proportional valves 17 and 27, respectively. Combustion is started and stopped, and the combustion amounts of the burners 12 and 22 are adjusted by the electromagnetic proportional valves 17 and 27. In addition, combustion air is supplied to the combustion casings 11 and 21 of the combustion units 1 and 2 via the blowers 18 and 28, respectively. The electromagnetic on-off valves 16 and 26, the electromagnetic proportional valves 17 and 27, and the blowers 18 and 28 are controlled by the controller 3 serving as control means. During the combustion operation of each of the combustion units 1 and 2, the combustion amount of the burners 12 and 22 corresponding to the hot water supply load and the heating load is calculated, and the opening degree of the electromagnetic proportional valves 17 and 27 is controlled in accordance with the combustion amount. At the same time, the rotational speeds of the blowers 18 and 28 are controlled so that an amount of combustion air corresponding to the amount of combustion is supplied.

  Combustion exhaust from both combustion sections 1 and 2 is discharged to the outside through a single exhaust passage 4. A CO sensor 5 for detecting the CO concentration in the combustion exhaust is disposed in the combustion exhaust merging portion 4 a that guides the combustion exhaust from each combustion unit 1, 2 to the exhaust passage 4. Input to the controller 3. When the controller 3 determines that the combustion state has deteriorated based on the detected CO concentration of the CO sensor 5, the controller 3 increases the amount of combustion air supplied to each combustion unit 1, 2 during the combustion operation, and determines the combustion state. Implement combustion improvement control to improve.

  The details of the combustion improvement control are as shown in FIG. 2. After the controller 3 is initialized at step S1 when the power is turned on, the CO sensor 5 is energized at step S2 for a predetermined time (about 40 seconds). Self-cleaning of the CO sensor 5 is performed. Next, in step S3, the air increase coefficient K1 of the hot water combustion unit 1 and the air increase coefficient K2 of the heating combustion unit 2 are both set to “1”. The air increase coefficients K1 and K2 are coefficients representing the ratio of the supply amount of combustion air to the reference air amount corresponding to the combustion amount. The controller 3 controls the blowers 18 and 28 so that the combustion air in an amount obtained by multiplying the air increase coefficients K1 and K2 by the reference air amount is supplied to the combustion units 1 and 2. The reference air amount is set to a theoretical air amount corresponding to the combustion amount or a value obtained by multiplying the theoretical air amount by a predetermined excess rate.

  Next, in step S4, it is determined whether or not at least one of the hot water combustion unit 1 and the heating combustion unit 2 is in a combustion operation. If the combustion operation is in progress, the CO sensor 5 is detected in step S5. Check if it is normal. If the CO sensor 5 is not normal, an error stop process is executed in step S6. In this stop process, the fact that the CO sensor 5 is abnormal is displayed and the combustion operation is stopped.

  If the CO sensor 5 is normal, it is determined in step S7 whether or not the detected CO concentration of the CO sensor 5 is equal to or higher than a predetermined value (for example, 300 ppm) continuously for a predetermined time (for example, 20 seconds). Specifically, there is provided a timer that starts timing when the detected CO concentration of the CO sensor 5 exceeds a predetermined value and resets to zero when the detected CO concentration falls below the predetermined value. When the time reaches a predetermined time, it is determined that the detected CO concentration of the CO sensor 5 is continuously higher than a predetermined value for a predetermined time. If the detected CO concentration of the CO sensor 5 is continuously higher than the predetermined value for a predetermined time, it is determined that the combustion state has deteriorated, and the air increase coefficients K1, K2 are set to “1” in step S8. Determine whether it is set. Note that when the detected CO concentration of the CO sensor 5 exceeds a predetermined value, it is possible to immediately determine that the combustion state has deteriorated. However, considering the stability of control, the primary CO concentration is increased. Then, it is made not to judge that the combustion state has deteriorated. When the process proceeds from step S7 to step S8, the timer is reset to zero.

  Here, after the power is turned on, when the process proceeds to step S8 for the first time, the air increase coefficients K1 and K2 are set to “1” in step S3. Therefore, the determination result in step S8 is “YES”. It becomes. In this case, the process proceeds to step S9, and the air increase coefficients K1 and K2 are set to the set values YK1 and YK2 stored in the memory 3a as storage means provided in the controller 3, and then the process returns to step S4.

  Each set value YK1, YK2 is set to an upper limit or a value in the vicinity of the upper limit in a range in which the deterioration of the combustion state due to the increase in the amount of combustion air in the normal combustion state does not occur. Here, the upper limit of the range is different between the hot water combustion unit 1 and the heating combustion unit 2, for example, “1.05” in the hot water combustion unit 1 and “1.04” in the heating combustion unit 2. May be. Accordingly, the set value YK1 in the hot water supply combustion unit 1 and the set value YK2 in the heating combustion unit 2 are individually set and stored in the memory 3a.

  As described above, when the air increase coefficients K1 and K2 are set to the set values YK1 and YK2, the supply amount of combustion air to the combustion units 1 and 2 is increased from the reference air amount, and incomplete combustion occurs. The combustion state of the burning part is improved. For example, if YK1 = 1.05 and YK2 = 1.04, the supply amount of combustion air to the hot water supply combustion unit 1 is increased by 5% of the reference air amount, and is used for combustion to the heating combustion unit 2 The supply amount of air is increased by 4% of the reference air amount. Further, during the simultaneous combustion operation of both the combustion units 1 and 2, only one of the combustion units 1 and 2, for example, only the hot water combustion unit 1 causes incomplete combustion, and the detected CO concentration of the CO sensor 5 exceeds a predetermined value. In this case, the air supply amount to the heating combustion unit 2 that normally burns is also increased. However, this increase amount is not enough to deteriorate the combustion state of the heating combustion unit 2 due to excessive air. The combustion section 2 is maintained in a normal combustion state. As a result, in many cases, the detected CO concentration of the CO sensor 5 becomes lower than a predetermined value, and it is avoided that the process proceeds to step S8 again.

  On the other hand, even if the supply amount of combustion air is increased as described above, when the detected CO concentration of the CO sensor 5 does not become lower than the predetermined value and the process proceeds to step S8 again, the air increase coefficients K1, K2 are already set. Are set to the set values YK1 and YK2, respectively, it is determined that YK1 and YK2 ≠ 1. In this case, the process proceeds to step S10 and incomplete combustion stop processing is executed. In this stop process, the fact that incomplete combustion has occurred is displayed and the combustion operation is stopped.

  In the above embodiment, the air increase coefficients K1 and K2 are set to the set values YK1 and YK2 when the process proceeds to step S9 with the first “YES” determination in step S7. It is also possible to increase each air increase coefficient K1, K2 stepwise toward each set value YK1, YK2. In this case, each time the air increase coefficient K1, K2 is increased by one step each time it is determined “YES” in step S7, each air increase coefficient K1, K2 is increased to each set value YK1, YK2. In addition, when it is determined “YES” in the step of S7, the incomplete combustion stop process is executed.

  As mentioned above, although embodiment which applied this invention to the hot water supply heating heat source machine was described, the hot water supply heat source machine provided with the combustion part for hot water supply and the combustion part for reheating of a bath, and also provided with three or more combustion parts The present invention can be similarly applied to a combined combustion apparatus.

Explanatory drawing which shows the structure of the composite combustion apparatus of embodiment of this invention. The flowchart which shows the content of combustion improvement control.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Combustion part for hot water supply, 2 ... Combustion part for heating, 12, 22 ... Burner, 18, 28 ... Blower, 3 ... Controller (control means), 3a ... Memory (storage means), 4 ... Exhaust passage, 4a ... Merge Part, 5 ... CO sensor.

Claims (2)

A combined combustion apparatus provided with at least two combustion sections with a built-in burner, each blower supplying combustion air to each combustion section, and combustion exhaust from each combustion section is guided to a single exhaust passage A CO sensor for detecting the CO concentration in the combustion exhaust disposed at the merging portion of the combustion exhaust, and each combustion unit in the combustion operation when it is determined that the combustion state has deteriorated based on the detected CO concentration of the CO sensor And a control means for controlling the blower so that the supply amount of the combustion air to the reference air amount corresponding to the combustion amount is increased,
Air increase set for each combustor to prevent deterioration of the combustion state due to the increase in combustion air in the normal combustion state, with the coefficient representing the ratio of the supply amount of combustion air to the reference air amount as the air increase coefficient Storage means for storing the set value of the coefficient;
When it is determined that the combustion state has deteriorated, the control means sets the amount of combustion air supplied to each combustion section during the combustion operation and sets the air increase coefficient of each combustion section stored in the storage means. A combined combustion apparatus configured to increase in accordance with a value.   2. The composite according to claim 1, wherein the set value of the air increase coefficient is set to an upper limit or a value in the vicinity of the upper limit of a range in which the deterioration of the combustion state due to the increase of the combustion air in the normal combustion state does not occur. Combustion device.

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