JP2008292039A - Combustion apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion apparatus capable of preventing the occurrence of a hunting phenomenon and the generation of a resonance sound at the initial time of ignition without fail. <P>SOLUTION: This combustion apparatus is provided with a burner for obtaining amounts of combustion in a plurality of stages by switching combustion parts 10a-10c, a fan 4 for supplying air for combustion into the burner 3, and a control means 25 for controlling the amount of the combustion of the burner 3. The controlling means 25 controls by providing a region of overlapping combustion where the same amount of combustion is obtained between a small amount of a combustion side at the stage of the amount of combustion where all the combustion parts 10a-10c are in combustion states and a large amount of the combustion side at the stage of the amount of combustion adjacent to a side where the number of combustion parts is reduced. The control means 25 is provided with a resonance sound avoidance control part 26 for increasing the minimum amount of combustion up to the amount of combustion set in advance to avoid a region where the resonance sound is generated from the start of the combustion of all the combustion parts 10a-10c to a time when a resonance sound avoidance time set in advance elapses when all the combustion parts 10a-10c are brought into the combustion states at the initial time of ignition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a combustion apparatus such as a water heater.

  Conventionally, in a combustion apparatus such as a water heater, there is known a combustion apparatus provided with a burner composed of a plurality of combustion sections so that a plurality of combustion amount ranges can be obtained by switching the number of combustion sections to be burned. (For example, refer to Patent Document 1).

  The switching of the combustion section in this type of burner will be described with reference to FIG. 5 in a configuration in which the combustion amount range is switched to three stages by the three combustion sections. One combustion section is combusted and controlled along the small input line A. When the target combustion amount is medium, two of the three combustion sections are combusted along the middle input line B. If the target combustion amount is large, the entire combustion part is combusted and controlled along the large input line C. Then, by making the maximum combustion amount Bmax in the medium input line B larger than the minimum combustion amount Cmin in the large input line C, the same combustion amount can be obtained between the middle input line B and the large input line C. A region Wb is provided. Similarly, by making the maximum combustion amount Amax in the small input line A larger than the minimum combustion amount Bmin in the middle input line B, the same combustion amount is obtained between the small input line A and the middle input line B. An overlapping area Wa to be provided is provided.

By the way, if the burner is cooled in the early stage of ignition, a resonance noise is generated when all the combusted parts are burned from the time of ignition in the cold burner and the minimum combustion amount Cmin in the large input line C is obtained. As shown in FIG. 5, the resonance sound generation region SL is generated at a position where it intersects with the minimum combustion amount Cmin in the large input line C at the initial stage of ignition, and disappears when the burner temperature rises. Therefore, in order to prevent the generation of resonance noise in the early stage of ignition, if the burner is a light and dark burner that obtains low NOx, the resonance noise generation region can be obtained by reducing the damper of the rich burner and changing the rich flame shape of the combustion section. Although it is conceivable that the SL is separated from the minimum combustion amount Cmin toward the large combustion amount, in this case, another resonance generation region SH generated near the maximum combustion amount Cmax in the large input line C shifts to the small combustion amount side. Therefore, since the maximum combustion amount Cmax is crossed, a resonance noise is generated during the maximum combustion of the burner. Further, it is conceivable that the minimum combustion amount Cmin in the large input line C is increased to C′min to be separated from the resonance sound generation region SL, and accordingly, the maximum combustion amount Bmax in the middle input line B, Even after the overlapping area with the minimum combustion amount C′min in the large input line C becomes narrow as Wb ′ in the figure and the burner temperature rises and the resonance sound generation area SL disappears, the medium input line B and the large input line C There is a risk of causing a hunting phenomenon in which the line C is switched while being repeatedly ignited and extinguished.
Japanese Patent Laid-Open No. 10-103668 (FIG. 1)

  Accordingly, an object of the present invention is to provide a combustion apparatus capable of suppressing the occurrence of a hunting phenomenon and reliably preventing the generation of a resonance sound at the initial stage of ignition.

  In order to achieve such an object, the present invention provides a burner that includes a plurality of combustion sections and obtains a plurality of combustion amount ranges by switching the number of combustion sections to be burned, and a fan that supplies combustion air to the burners. And a control means for controlling the amount of combustion for each stage and controlling the air volume of the fan in accordance with the amount of combustion in each stage, the control means comprising at least the combustion quantity of the stage where the entire combustion part is in the combustion state Combustion device that performs control by providing a predetermined overlapping region in which the same combustion amount is obtained between the small combustion amount side of the range and the large combustion amount side of the combustion amount range of the stage adjacent to the reduction side of the number of combustion parts In the above-mentioned control means, when all the combustion parts are in a combustion state at the initial stage of ignition, the control means is the minimum in the stage in which all the combustion parts are combusted until a predetermined resonance noise avoidance time has elapsed from the start of combustion of all the combustion parts. Combustion volume, avoiding the area where resonance noise occurs Characterized in that it comprises a resonant sound avoidance control section that increases to a predetermined combustion rate to.

  According to the present invention, when the burner is ignited by the resonance sound avoidance control unit provided in the control means and all the combustion parts are in a combustion state, the minimum combustion amount is reduced until the resonance sound avoidance time elapses. The combustion amount is increased to a predetermined amount so as to avoid the region where the resonance noise is generated. Accordingly, when the burner is cold at the time of ignition, even if combustion is performed with the minimum amount of combustion in the stage where all the combustion parts burn, the generation of resonance noise can be reliably prevented. And, when the burner temperature sufficiently rises due to the passage of the resonance noise avoidance time and the resonance noise is not generated, the increase in the minimum combustion amount is canceled, so that the predetermined overlap region is obtained, Occurrence of the hunting phenomenon can be prevented.

  Further, in the present invention, the resonance noise avoidance control unit increases the minimum combustion amount at a stage where all the combustion portions burn at the time of ignition to a predetermined combustion amount so as to avoid a resonance sound generation region, and The combustion amount is gradually decreased until the predetermined overlap region is formed within the avoidance time.

  According to the present invention, since the resonance noise avoidance control unit gradually decreases the minimum combustion amount increased at the time of ignition within the resonance noise avoidance time, a state where the overlapping region is narrow as the minimum combustion amount increases. Is gradually eliminated within the resonance sound avoidance time, and the hunting phenomenon can be made difficult to occur even during the resonance sound avoidance time.

  In the present invention, an outside air temperature detecting unit for detecting an outside air temperature is provided, and the control unit includes a correction unit that corrects the resonance sound avoidance time according to the outside air temperature detected by the outside air temperature detecting unit. It is characterized by providing.

  When the outside air temperature is low, the burner may be extremely cold due to the influence. Accordingly, in the present invention, the resonance noise avoidance time is lengthened by the correction unit to sufficiently raise the burner temperature after ignition, so that the generation of resonance noise can be reliably prevented. In addition, when the outside air temperature is relatively high, the burner temperature rises quickly after ignition, so the hunting phenomenon is shortened by the correction unit so that the predetermined overlapping region is formed earlier by reducing the resonance sound avoidance time. Can be prevented.

  Further, in the present invention, the control means includes a stop time timing unit for measuring the burner combustion stop time, and the resonance noise avoidance is determined according to the burner combustion stop time measured by the stop time timer unit. A correction unit for correcting the time is provided.

  When the burner combustion stop time is long, it is considered that the burner has cooled down, and there is a possibility that the increase in the burner temperature after ignition becomes relatively slow. Therefore, in the present invention, for example, when the burner combustion stop time measured by the stop time measuring unit is long, the resonance temperature avoidance time is lengthened by the correction unit, so that the burner temperature after ignition is sufficiently increased. It can be raised, and the generation of resonance can be reliably prevented. Further, when the burner combustion stop time is short, the burner is not completely cooled and the burner temperature rises relatively quickly after ignition. Thus, the hunting phenomenon can be prevented.

  As shown in FIG. 1, a hot water supply device 1 that is an embodiment of the combustion device of the present invention includes a burner 3, a fan 4 that supplies combustion air to the burner 3, and a hot water supply device 1. And a control device 5 for comprehensively controlling the operation. The burner 3 heats the heat exchanger 6 located above it. The heat exchanger 6 is connected between a water inlet pipe 7 whose upstream end is connected to a water pipe and the like, and a hot water outlet 8 whose downstream end is connected to a hot water currant (not shown). The control device 5 is connected to a remote controller 9 for setting the temperature of the hot water.

  The burner 3 is composed of three combustion sections (a first combustion section 10a, a second combustion section 10b, and a third combustion section 10c) having different combustion amounts, and a plurality of stages of combustion amount ranges can be obtained by combining the combustion sections. It is like that. Fuel gas is supplied to the burner 3 through a gas supply pipe 11. The gas supply pipe 11 is provided with an original gas solenoid valve 12, a gas proportional valve 13, and switching gas solenoid valves 14a, 14b, and 14c in this order from the upstream side. Each combustion part 10a, 10b, 10c is burned by opening each switching gas solenoid valve 14a, 14b, 14c. The burner 3 is ignited by a spark plug 16 driven by an igniter 15, and the ignition state after ignition is detected by a frame rod 17.

  The water inlet pipe 7 is provided with a flow rate sensor 18 for detecting the water flow rate from the water inlet pipe 7 to the hot water outlet pipe 8 and a water quantity servo 19 for adjusting the water quantity downstream thereof. The heat exchanger 6 is provided with a plurality of overheat prevention devices (bimetal switch 20 and temperature fuse 21), the outlet pipe 8 has an outlet temperature sensor 22 for detecting the hot water temperature near the outlet of the heat exchanger 6, and the downstream side. There is provided a tapping temperature sensor 23 for detecting the tapping temperature. The housing 2 is provided with an outside air temperature sensor 24 (outside air temperature detecting means of the present invention) for detecting the outside air temperature.

  The control device 5 includes combustion control means 25 (control means of the present invention) for controlling the combustion of the burner 3, and the combustion control means 25 includes a resonance noise avoidance control unit 26, a stop time counting unit 27, A correction unit 28 and a second correction unit 29 are provided. The stop time measuring unit 27 measures the time from when the combustion of the burner 3 is stopped until the next ignition. The outside temperature detected by the outside air temperature sensor 24 is input to the first correction unit 28, and the stop time measured by the stop time counting unit 27 is input to the second correction unit 29.

  Explaining the control of the combustion operation by the combustion control means 25, when the power supply is turned on and the user opens the hot water currant or the like connected downstream of the hot water discharge pipe 8, the flow sensor 18 causes the water flow. Detect and output a pulse signal. The combustion control means 25 detects the amount of ignition operation water based on the pulse signal output from the flow sensor 18 and first rotates the fan 4. Next, the combustion control means 25 opens the original gas solenoid valve 12 and the switching gas solenoid valve 14a, and operates the igniter 15. Then, the igniter 15 drives the spark plug 16 to ignite the first combustion part 10a of the burner 3.

  The combustion control means 25 adjusts the valve opening degree of the gas proportional valve 13 (fuel gas flow rate) so that the hot water temperature becomes a set temperature set by the remote controller 9 based on signals from the hot water temperature sensor 23 and the flow rate sensor 18. Supply amount), opening and closing of the switching gas solenoid valves 14b and 14c (ignition and extinguishing of the second combustion unit 10b and the third combustion unit 10c), and the rotation speed of the fan 4 (supply amount of combustion air). At this time, the combustion control means 25 opens the switching gas solenoid valve 14b and the switching gas solenoid valve 14c from the beginning of ignition according to the target combustion amount based on the set temperature set by the remote controller 9, and the first combustion unit 10a. The combustion amount range is switched to three stages by combining the combustion of the second combustion unit 10b and the third combustion unit 10c. More specifically, referring to FIG. 2, the combustion control means 25 performs control along the small input line A by burning only the first combustion section 10a when the target combustion amount is small. Further, when the target combustion amount is medium, the first combustion unit 10a and the second combustion unit 10b are burned to perform control along the middle input line B. Further, when the target combustion amount is large, the entire combustion section (all of the first combustion section 10a, the second combustion section 10b, and the third combustion section 10c) is burned and control along the large input line C is performed. Further, in such a control, the maximum combustion amount Bmax in the medium input line B is made larger than the minimum combustion amount Cmin in the large input line C, so that the same between the middle input line B and the large input line C. The overlapping region Wb in which the combustion amount is obtained is provided to prevent the hunting phenomenon in which the ignition and extinguishing of the third combustion unit 10c are repeated. Similarly, by making the maximum combustion amount Amax in the small input line A larger than the minimum combustion amount Bmin in the medium input line B, the same combustion amount is obtained between the small input line A and the medium input line B. The overlapping region Wa is provided to prevent a hunting phenomenon in which ignition and extinguishing of the second combustion unit 10b are repeated. Then, when the hot water currant or the like is closed by the user, the detection of the water flow by the flow sensor 18 is stopped, and the combustion control means 25 closes the original gas solenoid valve 12 and the switching gas solenoid valves 14a, 14b, 14c. Extinguish the burner 3.

  Here, the operation of the resonance avoidance control unit 26 will be described. When all of the first combustion section 10a, the second combustion section 10b, and the third combustion section 10c of the burner 3 are in a combustion state at the initial stage of ignition, the combustion control means 25 performs combustion along the large input line C in FIG. Control the amount. At this time, if the burner 3 is cold, as shown in FIG. 2, the resonance generation region SL is located at a position where the minimum combustion amount Cmin (approximately 13000 Kcal / h in the present embodiment) in the large input line C intersects. Exists. Accordingly, when combustion is performed with the minimum combustion amount Cmin in the large input line C in this state, a resonance sound is generated. Although another resonance generation region SH appears in the vicinity of the maximum combustion amount Cmax in the large input line C, it does not become a combustion state in which resonance noise is generated regardless of the maximum combustion amount Cmax in the large input line C. Therefore, the resonance avoidance control unit 26 performs control for avoiding the resonance in the resonance generation region SL according to the procedure shown in FIG. That is, immediately after ignition in STEP1, the process proceeds to STEP2, and when all of the first combustion part 10a, the second combustion part 10b, and the third combustion part 10c of the burner 3 are in the combustion state (switching gas solenoid valves 14a, 14b, 14c If all of the above are opened, the process proceeds to STEP3. In STEP 3, the minimum combustion amount in the large input line C is determined from Cmin to a predetermined combustion amount so as to avoid the resonance sound generation region SL until a predetermined resonance sound avoidance time elapses (in this embodiment, 10 seconds). A combustion amount lower limit increasing process for increasing to C′min (about 14500 Kcal / h in the present embodiment) is performed. Specifically, control is performed so that the opening degree of the gas proportional valve 13 does not become smaller than a predetermined opening degree. The resonance noise avoidance time used here is the time until the resonance noise generation region SL crossing the minimum combustion amount Cmin of the large input line C in FIG. 2 disappears due to the temperature rise of the burner 3, and is performed by the inventor. Based on these tests, the burner 3 is predetermined according to conditions such as the capacity (maximum combustion amount) and the type of fuel gas. Next, when the combustion amount lower limit increasing process over the resonance noise avoidance time is completed, the routine proceeds to STEP 4 where the minimum combustion amount is returned to Cmin and normal control along the large input line C is performed. Thereby, after the resonance sound avoidance time has elapsed, it is possible to ensure a wide overlapping area Wb of the medium input line B and the large input line C. Further, in STEP2, when some of the first combustion unit 10a, the second combustion unit 10b, and the third combustion unit 10c of the burner 3 are in a combustion state (a part of the switching gas solenoid valves 14a, 14b, 14c is closed). 2), the control along the middle input line B or the small input line A in FIG. 2 is performed and does not cross the resonance sound generation region SL, and there is very little possibility that the resonance sound is generated. Then, the process proceeds to STEP 4 without performing the control by the resonance sound avoidance control unit 26. Thereby, it is possible to ensure a wide overlapping area Wb between the middle input line B and the large input line C immediately after ignition.

  Further, in the combustion amount lower limit increasing process in STEP 3, the resonance noise avoidance time correction process is performed. That is, as shown in FIG. 4, when the combustion amount lower limit increasing process is started by the resonance avoidance control unit 26 in STEP 3-1, first, the process proceeds to STEP 3-2 and the first correction unit 28 is operated to When the outside air detected by the temperature sensor 24 is lower than 0 ° C., the process proceeds to STEP 3-3. When the temperature of the outside air is lower than 0 ° C., it is considered that the temperature of the burner 3 is low due to the influence. Therefore, in STEP3-3, the resonance sound avoidance time predetermined in the resonance sound avoidance control unit 26 is determined. When the corrected resonance noise avoidance time has elapsed, the process proceeds to STEP 3-4 and the combustion amount lower limit increasing process is terminated. Let

  In STEP 3-2, when the outside air detected by the outside air temperature sensor 24 is 0 ° C. or higher, the process proceeds to STEP 3-5. In STEP 3-5, the second correction unit 29 is operated, and when the stop time of the burner 3 measured by the stop time measuring unit 27 is 30 minutes or more, the process proceeds to STEP 3-3. When the stop time is 30 minutes or more, it is considered that the temperature of the burner 3 has cooled down. Therefore, in STEP3-3, the resonance sound avoidance time set in advance in the resonance sound avoidance control unit 26 is increased. Thus, when the corrected resonance sound avoidance time has elapsed, the process proceeds to STEP 3-4 and the combustion amount lower limit increasing process is terminated. Further, in STEP 3-5, when the stop time is less than 30 minutes, it is considered that the burner 3 has not cooled down. Therefore, the process proceeds to STEP 3-6, and the resonance sound set in advance by the resonance sound avoidance control unit 26 is reached. The avoidance time (10 seconds in the present embodiment) is set, and when this resonance noise avoidance time has elapsed, the routine proceeds to STEP 3-4, where the combustion amount lower limit increasing process is terminated.

  In this way, by performing the combustion amount lower limit increasing process by the resonance noise avoidance control unit 26, even if the control along the large input line C in FIG. The resonance noise is prevented from being generated during combustion, and the minimum combustion amount is returned to Cmin after the resonance noise avoidance time has elapsed and the burner 3 rises to a temperature at which resonance noise does not occur. Since normal control along C is performed, a sufficient overlap region Wb can be provided, and the hunting phenomenon can be prevented.

  Note that either the correction determination based on the temperature of the outside air shown in STEP 3-2 or the correction determination based on the stop time of the burner 3 shown in STEP 3-5 may be performed first, and only one of them may be performed. It may be.

  Further, the resonance noise avoidance control unit 26 gradually decreases the minimum combustion amount in the large input line C shown in FIG. 2 from C′min to Cmin from the ignition time to the resonance noise avoidance time in the combustion amount lower limit increasing process of STEP 3. You may make it make it. According to this, the generation of the resonance sound is less likely to occur due to the rise of the burner temperature as time elapses, so that the overlapping region Wb gradually expands within the resonance sound avoidance time, thereby making the hunting phenomenon as difficult as possible. be able to.

Explanatory drawing which shows schematic structure of the implementation apparatus of this invention. Explanatory drawing which shows the relationship between the fan rotation speed and combustion amount in this embodiment. The flowchart which shows the action | operation of a resonance sound avoidance control part. The flowchart which shows the correction process of resonance sound avoidance time. Explanatory drawing which shows the relationship between the conventional fan rotation speed and combustion amount.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Hot water supply apparatus (combustion apparatus), 3 ... Burner, 4 ... Fan, 10a ... 1st combustion part (combustion part), 10b ... 2nd combustion part (combustion part), 10c ... 3rd combustion part (combustion part), 24 ... Outside air temperature sensor (outside air temperature detecting means), 25 ... Combustion control means (control means), 26 ... Resonance sound avoidance control section, 27 ... Stop time measuring section, 28 ... First correction section (correction section), 29 ... a second correction unit (correction unit).

Claims (4)

A burner that includes a plurality of combustion sections and obtains a combustion range of multiple stages by switching the number of combustion sections to be burned, a fan that supplies combustion air to the burners, and controls the combustion volume for each stage Control means for controlling the fan air volume in accordance with the combustion amount of each stage, and the control means includes at least a small combustion amount side of the combustion amount range of the stage where all the combustion parts are in a combustion state, and a reduction in the number of combustion parts. In a combustion apparatus that performs control by providing a predetermined overlapping region where the same combustion amount is obtained between the combustion amount range of the stage adjacent to the side and the combustion amount range,
The control means is configured such that when all the combustion parts are in a combustion state at the initial stage of ignition, the minimum combustion amount in the stage where all the combustion parts are combusted until a predetermined resonance noise avoidance time elapses from the start of combustion of all the combustion parts. A combustion apparatus, comprising: a resonance sound avoidance control unit that increases a combustion amount to a predetermined combustion amount so as to avoid a resonance sound generation region.   The resonance noise avoidance control unit increases a minimum combustion amount in a stage where all combustion portions burn at the time of ignition to a predetermined combustion amount so as to avoid a region where resonance noise is generated, and within the resonance noise avoidance time, 2. The combustion apparatus according to claim 1, wherein the combustion amount is gradually decreased until a predetermined overlapping region is formed. An outside air temperature detecting means for detecting the outside air temperature is provided,
3. The combustion apparatus according to claim 1, wherein the control unit includes a correction unit that corrects the resonance sound avoidance time in accordance with an outside air temperature detected by the outside air temperature detecting unit.   The control means includes a stop time timer for measuring the combustion stop time of the burner, and a correction unit for correcting the resonance noise avoidance time according to the burner combustion stop time measured by the stop time timer. The combustion apparatus according to any one of claims 1 to 3, wherein the combustion apparatus is provided.

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