JP2017044410A - Combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform an accurate detection of engine speed even in the case that a certain noise is mixed with pulse outputted in response to a rotation of a fan motor at a combustion apparatus.SOLUTION: A combustion apparatus 1 comprises a fan motor 6; a rotation sensor 18; a motor speed detector 16 for use in detecting a motor speed of the fan motor 6 on the basis of a pulse outputted by the rotation sensor 18; and a control unit 20 for controlling combustion including control over a motor speed of the fan motor 6 on the basis of the motor speed detected by the motor speed detector 16. The motor speed detector 16 detects a motor speed of the fan motor 6 in which a time width of pulse series composed of continuous pulses of a total number of N + 2M that pulse series composed of continuous numbers N of pulses are added with the number of 2M correction pulses subsequent before or after the pulse series is applied as a time required that the fan motor 6 is rotated by a prescribed amount when the numbers of M with time width less than the prescribed time are included in the pulse series composed of continuous pulses of the number of N.SELECTED DRAWING: Figure 3

Description

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

  Conventionally, in a combustion apparatus such as a hot water supply apparatus, the rotation speed of a fan that supplies combustion air to a burner has been detected in order to perform combustion control. Specifically, a pulse is output according to the rotation of the fan motor, the output pulse is input to the control microcomputer of the combustion apparatus, and the control microcomputer detects the rotation speed based on the input pulse.

  For example, Patent Document 1 discloses a fan motor control device that detects the rotational speed of a fan motor from pulses output based on a detection signal of a Hall IC built in the fan motor. In order to maintain sufficient combustion performance in the burner, this control device sets the number of revolutions of the fan motor in advance corresponding to the amount of combustion of the burner (fuel supply amount), and controls the number of revolutions of the fan motor. To do.

JP-A-10-184588

  However, in the conventional combustion apparatus described above, there are cases where electrical noise (hereinafter, also simply referred to as noise) is mixed in pulses output in accordance with the rotation of the fan motor. For this reason, there has been a problem that an accurate rotational speed cannot be detected and combustion control is affected.

  Therefore, an object of the present invention is to accurately detect the rotational speed even when noise is mixed in a pulse output in accordance with the rotation of the fan motor in the combustion apparatus.

  A combustion apparatus according to an aspect of the present invention includes a fan motor for supplying combustion air, and a sensor that outputs a total of N high-level pulses and low-level pulses during normal operation while the fan motor rotates a predetermined amount. A rotation speed detector for detecting the rotation speed of the fan motor based on a pulse output from the sensor; and a rotation speed control for the fan motor based on the rotation speed detected by the rotation speed detector. A combustion apparatus comprising: a controller for performing combustion control, wherein the rotational speed detector includes M pulses having a time width less than a predetermined time in a pulse train including the N pulses that are continuous. The time width of the pulse train consisting of N + 2M consecutive pulses is obtained by adding 2M correction pulses preceding or following to the pulse train consisting of N consecutive pulses. The number of rotations of the fan motor is detected as the time required for the fan motor to make a predetermined rotation. Here, N is a positive integer of 2 or more, and M is a positive integer. Also, the high level pulse and the low level pulse are defined as separate pulses, respectively. That is, a portion that outputs a high level signal in one pulse is defined as a high level pulse, and a portion that outputs a low level signal is defined as a low level pulse.

  The fan rotation speed is detected based on a pulse output from a sensor attached to the motor, and the length of a pulse train for one rotation of the motor varies depending on the rotation speed of the motor. For this reason, when noise is mixed in the pulse, the end of the pulse train for one rotation is not known. According to the above configuration, when counting a pulse with a short pulse width, two more pulses are counted. The increased time width of the correction pulse is added to the total time for one rotation. As a result, even when noise is mixed in the output pulse, the accurate rotation speed can be calculated by correcting the pulse data including the noise. In addition, since the pulse following the pulse train is used as the correction pulse, the continuity of the pulse data is maintained and the correction accuracy is good.

  When the 2M correction pulses include K pulses having a time width less than the predetermined time, the rotation number detector may include a pulse train composed of consecutive N + 2M pulses before or after the pulse train. The number of rotations of the fan motor is detected using the time width of the pulse train consisting of a total of N + 2M + 2K continuous pulses, to which 2K correction pulses are added, as the time required for the fan motor to make a predetermined rotation. May be. Here, K is a positive integer.

  Since the combustion apparatus is equipped with various electrical components (power supply, fan motor, controller), electrical noise (power supply noise, electromagnetic noise, etc.) is frequently generated in the equipment. According to the above configuration, even when noise is further mixed in the correction pulse, the pulse data can be corrected by adding a new pulse.

  A combustion apparatus according to another aspect of the present invention includes a fan motor for supplying combustion air, and a sensor that outputs a total of N high-level pulses and low-level pulses during normal operation while the fan motor rotates a predetermined amount. And a rotational speed detector for detecting the rotational speed of the fan motor based on a pulse output from the sensor, and a rotational speed control of the fan motor based on the rotational speed detected by the rotational speed detector. And a controller for performing combustion control, the rotational speed detector including 2P correction pulses that precede or follow the pulse train composed of consecutive N pulses. In addition, the time width of the pulse train composed of a total of N + 2P continuous pulses is set as the time required for the fan motor to make a predetermined rotation. Note that P is the number of pulses having a time width less than a predetermined time included in the pulse train composed of the N + 2P consecutive pulses. Here, P is a positive integer.

  The rotational speed detector determines whether or not the difference between the target rotational speed of the fan motor and the detected rotational speed is within a predetermined rotational speed range, and is within the predetermined rotational speed range; In addition, when the rotation speed detected this time fluctuates more than a predetermined rotation speed from the rotation speed detected last time, the rotation speed detected last time may be regarded as the rotation speed detected this time.

  According to the above configuration, when the detected rotation speed fluctuates greatly in the steady state, it is considered that the detection is erroneous due to noise mixing, and the previous value is adopted, so that the influence of noise can be eliminated. In addition, in the transient state where the control is unstable, the determination of the fluctuation of the rotational speed is not performed, so that erroneous detection can be avoided.

  According to the present invention, accurate rotation speed detection can be performed even when noise is mixed in a pulse output in accordance with the rotation of the fan motor in the combustion apparatus.

FIG. 1 is a schematic diagram showing an example of a combustion apparatus according to an embodiment of the present invention. FIG. 2 is a flowchart showing the flow of noise correction processing included in the output pulse of the rotation sensor. FIG. 3 is a timing chart showing an example of output pulses of the rotation sensor. FIG. 4 is a table showing an example of pulse data timed according to the output pulse of the rotation sensor. FIG. 5 is a flowchart showing the flow of noise removal processing included in the detected rotation speed of the fan motor. FIG. 6 is a graph showing temporal changes in the target rotational speed and detected rotational speed of the fan motor.

  Hereinafter, preferred embodiments will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout all the drawings, and redundant description thereof is omitted. Further, the present invention is not limited to the following embodiment.

[Combustion device configuration]
FIG. 1 is a schematic diagram showing an example of a combustion apparatus according to an embodiment of the present invention. The combustion apparatus 1 of this embodiment is a gas combustion type hot water supply apparatus. As shown in FIG. 1, a burner 3 and a heat exchanger 4 are accommodated in the combustion chamber of the casing 2 of the combustion apparatus 1. An air supply unit 2 a is provided at the lower part of the casing 2. A combustion fan 7 (sirocco fan) that is rotationally driven by a fan motor 6 is disposed inside the fan case 5 that is connected to the air supply unit 2a. An exhaust part 2 b is provided in the upper part of the casing 2.

  A fuel supply pipe 8 for supplying fuel gas is connected to the burner 3, and a hot water supply pipe 9 is connected to the heat exchanger 4. A spark plug 10 that is actuated by an igniter (not shown) is disposed in the vicinity of the upper flame hole of the burner 3, and the igniter of the spark plug 10 is controlled by a hot water supply controller 12. A flow rate sensor 13 is interposed in the hot water supply pipe 9, and a detection signal of the flow rate sensor 13 is input to the hot water supply controller 12. A gas proportional valve 11 is interposed in the fuel supply pipe 8, and the gas proportional valve 11 is configured to be opened and closed by a hot water supply controller 12. The gas proportional valve 11 is composed of, for example, a proportional electromagnetic valve. The gas pressure supplied to the burner 3 is controlled by the opening degree control of the gas proportional valve 11 according to the command from the hot water supply controller 12. The amount of gas supplied to the burner 3 per unit time is controlled by controlling the gas pressure.

  The set temperature of the hot water heater is input to the hot water controller 12. Further, detection values obtained by the flow rate sensor 13, the rotational speed detector 16 and the temperature sensor (not shown) are input to the hot water supply controller 12. The hot water supply controller 12 performs combustion control so that the hot water temperature from the hot water supply pipe 9 is controlled according to the set temperature. The hot water supply controller 12 outputs a control command for controlling the opening degree of the gas proportional valve 11 to the gas proportional valve 11, and outputs the target rotational speed of the combustion fan 7 to the fan drive controller 17. The function of the hot water controller 12 is realized by, for example, a microcomputer.

  In this embodiment, the target rotational speed is the amount of air at which the air-fuel ratio with the gas amount becomes a predetermined value (for example, the ideal air-fuel ratio) when the gas amount corresponding to the final target gas pressure is supplied to the burner 3. Is equivalent to the rotation speed when the combustion fan 7 supplies the gas. That is, the target rotational speed is determined in accordance with the final target gas pressure. When the opening of the gas proportional valve 11 is set to an opening corresponding to the final target gas pressure and the rotation speed of the combustion fan 7 is equal to the target rotation speed, combustion in the burner 3 is performed with a predetermined air-fuel ratio ( It is understood that the ideal state according to (theoretical air-fuel ratio) is obtained.

  Next, the configuration of the controller 20 of the fan motor 6 will be described. The controller 20 includes a fan drive power controller 14, a current value detector 15, a rotation speed detector 16, and a fan drive controller 17.

  The fan drive power controller 14 supplies drive power to the fan motor 6 based on a control signal from the fan drive controller 17 to rotate the fan motor 6. The fan drive power controller 14 may be configured to PWM control the drive power to the fan motor 6 based on the control signal from the fan drive controller 17, or the direct current corresponding to the control signal from the fan drive controller 17. The power supply may be supplied to the fan motor 6.

  The current value detector 15 detects the drive current value of the fan motor 6 based on the drive power supplied to the fan motor 6 by the fan drive power controller 14. The current value detector 15 can be configured by a known current sensor. The current value detected by the current value detector 15 can be detected as an effective current value of the driving power of the fan motor 6 by a current transformer when the fan motor 6 is PWM-controlled. Further, in order to output a current value as a digital signal to the microcomputer, the detected current value can be pulse width modulated using a triangular wave.

  The rotation speed detector 16 detects the rotation speed of the fan motor 6 based on the output pulse of the rotation sensor 18. The rotation speed detection operation will be described later. The rotation sensor 18 outputs an output pulse corresponding to the rotation of the fan motor 6 as a detection signal to the rotation speed detector 16. In the present embodiment, the rotation sensor 18 is a Hall IC including a plurality of Hall elements built in the fan motor 6. The rotation sensor 18 is configured to output a total of N high level pulses and low level pulses during normal operation while the fan motor 6 rotates a predetermined amount. Here, N is a positive integer of 2 or more. Here, the high level pulse and the low level pulse are defined as separate pulses, respectively. That is, a portion that outputs a high level signal in one pulse is defined as a high level pulse, and a portion that outputs a low level signal is defined as a low level pulse. The rotation speed detector 16 measures the time required to detect a predetermined pulse and the high level time and low level time of each pulse in the predetermined pulse based on the pulse output from the rotation sensor 18. It has a timer function and a counter function that counts the number of times less than the predetermined time among the high level time and the low level time of each pulse in the measured predetermined pulse. Each function of the rotation speed detector 16 is realized by, for example, a microcomputer including an arithmetic circuit, a memory, an input / output interface, a timer, a counter, and the like.

  The fan drive controller 17 controls the rotational speed of the combustion fan 7 in accordance with the target rotational speed instructed from the hot water supply controller 12. Specifically, feedback control for increasing or decreasing the fan driving power is executed based on a comparison between the detected rotational speed detected by the rotational speed detector 16 and the target rotational speed.

  As described above, in the combustion apparatus 1, the fan drive controller 17, together with the hot water supply controller 12, performs combustion including the rotational speed control of the fan motor 6 based on the detected rotational speed detected by the rotational speed detector 16. It is configured to perform control. Note that the functions of the fan drive controller 17 and the hot water supply controller 12 may be realized by a common microcomputer.

[Fan speed detection operation: Noise correction]
Next, the fan rotation speed detection operation of the rotation speed detector 16 will be described. The rotation speed detector 16 performs noise correction processing included in the output pulse of the rotation sensor 18 prior to detecting the fan rotation speed. The noise correction process will be described with reference to the flowchart of FIG.

  First, the rotation speed detector 16 measures the pulse time of the output pulse of the rotation sensor 18 (step S1). FIG. 3 is a timing chart showing an example of output pulses of the rotation sensor 18. Here, the output pulses are shown as rectangular waves for the sake of simplicity, and pulse numbers are given in the oldest order. As shown in FIG. 3, the upper stage shows the output pulse train during normal operation. A total of 8 (N = 8) high level pulses and low level pulses are alternately output during one rotation of the fan motor. Although the pulse widths are ideally the same here, the pulse widths per pulse are actually different due to variations due to the effects of sensor element mounting position, switching timing, and the like.

  The middle row shows the waveform when noise at one place is mixed in the output pulse train. A third low level pulse with a short pulse width is generated during the output of the second high level pulse. The lower part shows a waveform when noise in two places is mixed in the output pulse train. A third low level pulse with a short pulse width is generated during the output of the second high level pulse. Further, an eighth high level pulse with a short pulse width is generated during the output of the seventh low level pulse. The rotation speed detector 16 sequentially measures the time width of each pulse.

  The rotation speed detector 16 determines whether or not the time width of the pulse measured in step S1 is equal to or longer than a predetermined time (step S2). In the present embodiment, the predetermined time is 250 [μs]. Since the combustion apparatus 1 is mounted with various electrical components (power supply, fan motor, controller), electrical noise (power supply noise, electromagnetic noise, etc.) is frequently generated in the equipment. When the pulse time width is less than 250 [μs], it is considered that it is caused by such noise, not due to variations in the mounting position of the sensor element. The predetermined time may be arbitrarily set according to the actually generated noise level. When the pulse width is equal to or longer than the predetermined time (YES in step S2), the timekeeping is continued successively until it reaches 8 (N = 8), which is the number of pulse times corresponding to one motor rotation (step S3). On the other hand, when a pulse having a time width less than the predetermined value is included, the pulse count is increased by two. At this time, the number M of pulses having a time width less than a predetermined time is counted. Here, M is a positive integer. And it returns to step S1 and time-measures the next pulse (step S4).

  The rotation speed detector 16 stores the pulse data timed in steps S1 to S4 in a memory. FIG. 4 is a table showing an example of data timed according to the output pulse of the rotation sensor 18. The upper, middle, and lower pulse data shown in FIG. 4 correspond to the upper, middle, and lower output pulses in FIG. 3, respectively. The numbers in the table correspond to the pulse numbers in FIG. H indicates a high level pulse, L indicates a low level pulse, and the numerical values in the table indicate the time width of each pulse. The unit of time is milliseconds (ms). Here, the pulse data of eight pulses (No. 1 to No. 8) corresponding to one rotation of the motor and the following eight correction pulses (No. 9 to No. 16) are stored in the memory. Yes. In the present embodiment, pulse data corresponding to 16 pulses is stored in the memory when detecting the fan rotation speed. In other words, the latest 16 pieces of pulse data are always stored in the memory and updated at any time.

  The rotation speed detector 16 calculates the fan rotation speed based on the pulse data stored in the memory every predetermined time (for example, 10 ms). When the pulse train composed of consecutive N pulses includes M pulses having a time width less than a predetermined time, the rotational speed detector 16 adds 2M corrections to the pulse train composed of consecutive N pulses. The number of rotations of the fan motor is calculated using the time width of the pulse train consisting of a total of N + 2M continuous pulses, plus the number of pulses used, as the time required for the fan motor to make a predetermined rotation. It is a number.

  The pulse data shown in the upper part of FIG. 4 corresponds to the output pulse during normal operation. Therefore, a pulse train composed of 8 (N = 8) continuous pulses corresponding to one rotation of the motor does not include a pulse having a time width less than a predetermined time (M = 0). The rotational speed detector 16 calculates the rotational speed of the fan motor, using the time width of the pulse train of the total of eight fan motors as the time required for one rotation of the fan motor, and sets this as the detected rotational speed. Since each pulse time width is 1.5 [ms], the time required for one rotation is 12 [ms]. In this case, the fan detection rotational speed is 5000 [rpm].

The pulse data shown in the middle part of FIG. 4 corresponds to the case where noise at one place is mixed in the output pulse train. Therefore, 8 pulses (N = 8) corresponding to one rotation of the motor include one pulse whose time width is less than a predetermined time (M = 1). The number of revolutions detector 16 is the time required for one rotation of the fan motor, with a total of 10 (N + 2M) pulse widths obtained by adding the following two correction pulses to N pulse trains. As a result, the rotation speed of the fan motor is calculated, and this is set as the detected rotation speed. The time required for one rotation of the fan motor is corrected by adding a total of 10 pulse widths as follows.
1.5 + 0.7 + 0.1 + 0.7 + 1.5 + 1.5 + 1.5 + 1.5 + 1.5 + 1.5 = 12 [ms]
Thus, even when one noise pulse is included, the fan detection rotational speed becomes 5000 [rpm] by correction.

The pulse data shown in the lower part of FIG. 4 corresponds to the case where noise at two places is mixed in the output pulse train. Therefore, 8 pulses (N = 8) corresponding to one rotation of the motor include two pulses having a time width less than a predetermined time (M = 2). The number of revolutions detector 16 is the time required for the fan motor to make one revolution for a total of 12 (N + 2M) pulse widths obtained by adding the subsequent four correction pulses to the N pulse trains. As a result, the rotation speed of the fan motor is calculated, and this is set as the detected rotation speed. The time required for one rotation of the fan motor is corrected by summing up a total of 12 pulse widths as follows.
1.5 + 0.7 + 0.1 + 0.7 + 1.5 + 1.5 + 0.7 + 0.1 + 0.7 + 1.5 + 1.5 + 1.5 = 12 [ms]
Thus, even when two noise pulses are included, the fan detection rotational speed is 5000 [rpm] by correction.

  As described above, the fan detected rotation speed is detected based on the pulse output from the rotation sensor 18 attached to the motor, but the length of the pulse train for one rotation of the motor varies depending on the rotation speed of the motor. For this reason, when noise is mixed in the pulse, the end of the pulse train for one rotation is not known. According to this embodiment, when a pulse with a short pulse width is counted, the number of pulses to be counted is further increased by two, and the time width of the increased correction pulse is added to the total time for one rotation, whereby the output pulse is Even when noise is mixed, the accurate rotation speed can be calculated by correcting the pulse data including the noise. Further, since the pulse following the pulse train is used as the correction pulse, the continuity of the pulse data is maintained and the correction accuracy is good.

  In addition, since the combustion apparatus 1 is mounted with various electrical components (power supply, fan motor, controller), electrical noise (power supply noise, electromagnetic noise, etc.) is frequently generated in the equipment. In the present embodiment, the case where noise is not included in the correction pulse has been described (see pulse data No. 9 to No. 16 in FIG. 4), but the present invention is not limited to this. When the 2M correction pulses include K pulses having a time width less than a predetermined time, the rotation speed detector 16 adds 2K corrections to a pulse train composed of consecutive N + 2M pulses. The number of rotations of the fan motor may be detected with the time width of a pulse train composed of a total of N + 2M + 2K continuous pulses added with the pulses for use as the time required for the fan motor to make a predetermined rotation. Here, K is a positive integer. Thereby, even when noise is further mixed in the correction pulse, the pulse data can be corrected by adding a new pulse.

  By the way, in this embodiment, in the combustion apparatus 1 which is a gas combustion type hot water supply apparatus, air-fuel ratio control is performed to appropriately control the air amount so as to maintain a predetermined air-fuel ratio (for example, theoretical air-fuel ratio). In the air-fuel ratio control, the gas pressure supplied to the burner 3 is adjusted by controlling the opening of the gas proportional valve 11, and the air amount is controlled by controlling the fan speed. Since the detected rotation speed of the fan is detected by counting pulses output from the rotation sensor 18 attached to the fan motor, the responsiveness of the rotational speed control of the combustion fan is the response of the opening control of the gas proportional valve 11. It becomes low compared to sex. According to this embodiment, even if noise is mixed in the pulse, the rotational speed can be detected in real time while correcting the data. Therefore, the rotational speed detection speed can be improved, and the air-fuel ratio control of the gas burner can be suitably performed.

[Fan rotation speed detection operation: Noise reduction]
The rotational speed detector 16 calculates the detected rotational speed of the fan as described above, and then performs noise removal processing included in the detected rotational speed. The noise removal process will be described with reference to the flowchart of FIG.

  First, the rotation speed detector 16 determines whether or not the fan is in a steady state (step S11). Specifically, the rotational speed detector 16 determines whether or not the difference between the target rotational speed of the fan motor 6 and the detected rotational speed is within a predetermined rotational speed range. In the present embodiment, the predetermined rotational speed range is ± 500 [rpm], but may be arbitrarily set.

  Next, when the fan is in a steady state (YES in step S11), the rotational speed detector 16 determines whether or not the detected rotational speed has changed within a predetermined time (step S12). In the present embodiment, since the detected rotational speed is calculated every 10 [ms], it is determined whether or not the difference between the detected rotational speed before 10 [ms] and the latest detected rotational speed has changed by ± 200 [rpm] or more. However, it may be arbitrarily set according to the actually generated noise level.

  When the rotation speed detected this time in step S12 fluctuates more than a predetermined rotation speed from the rotation speed detected last time, the rotation speed detected last time is regarded as the rotation speed detected this time (step S13). As a result, when the detected rotation speed greatly fluctuates within a certain period of time in a steady state, it is regarded as erroneous detection due to noise mixing, and the previous value is adopted, thereby removing the influence of noise.

  On the other hand, when the fan is not in a steady state in step S11 (NO in step S11), the current value is adopted. FIG. 6 is a graph showing temporal changes in the target rotational speed Fr and the detected rotational speed Fc of the fan motor. The vertical axis of the graph is the fan speed [rpm], and the horizontal axis is the time [s]. As shown in FIG. 6, the target rotational speed Fr changes in response to changes in the environment of the combustion apparatus 1 (set temperature, hot water supply flow rate, etc.). This change is not necessarily smooth in terms of time, and may change abruptly (discontinuously). The fan drive controller 17 controls the rotational speed of the combustion fan 7 so as to follow the change in the target rotational speed Fr. However, since the responsiveness of the rotational speed control of the combustion fan 7 is low, the rotational speed of the combustion fan 160 is low. Normally, a transient state in which the target rotational speed Fr and the actual rotational speed are greatly different occurs in the control. Therefore, the rotational speed fluctuation determination is not performed in a transient state where the control is unstable. Thereby, erroneous detection can be avoided.

In the present embodiment, correction is performed using the pulse that follows the pulse train. However, correction may be performed using the pulse that precedes the pulse train. When the noise is low, the detected rotation speed can be calculated with the latest pulse train by correcting with the pulse following the pulse train, rather than with the pulse following the pulse train. Further, correction may be made with some pulses before and after the pulse train.
In this embodiment, the number of correction pulses for one rotation is the number corresponding to one rotation, but is arbitrary. For example, eight or more may be used depending on the noise environment.

In the present embodiment, the rotation sensor 18 is a Hall IC including a plurality of Hall elements built in the fan motor 6, but is not limited to this. If it is configured to output a total of N high level pulses and low level pulses during normal operation while the fan motor 6 rotates a predetermined amount, the electromagnetic wave attached to the rotating body of the fan motor 6 A pickup type sensor may be used, for example, an optical rotary encoder or resolver.
Although the combustion apparatus 1 of the said embodiment illustrated the combustion apparatus for hot water heaters, you may apply this invention to the combustion apparatus for heaters, such as a gas fan heater.

  From the foregoing description, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention.

  The present invention can be used for noise countermeasures in pulse detection of a combustion fan.

DESCRIPTION OF SYMBOLS 1 Combustor 2 Casing 3 Burner 4 Heat exchanger 5 Fan case 6 Fan motor 7 Combustion fan 8 Fuel supply pipe 9 Hot water supply pipe 10 Spark plug 11 Gas proportional valve 12 Hot water controller 13 Flow rate sensor 14 Fan drive power controller 15 Current value Detector 16 Rotational speed detector 17 Fan drive controller 18 Rotation sensor (Hall element)
20 Controller

Claims (4)

A fan motor for supplying combustion air;
A sensor that outputs a total of N high level pulses and low level pulses during normal operation while the fan motor rotates a predetermined amount;
A rotational speed detector for detecting the rotational speed of the fan motor based on a pulse output from the sensor;
A controller that performs combustion control including rotational speed control of the fan motor based on the rotational speed detected by the rotational speed detector;
A combustion apparatus comprising:
The rotational speed detector follows the pulse train consisting of N consecutive pulses before or after the pulse sequence consisting of the N consecutive pulses when M pulses having a time width less than a predetermined time are included in the pulse train consisting of the N pulses. The number of rotations of the fan motor is detected with the time width of a pulse train composed of a total of N + 2M continuous pulses to which 2M correction pulses are added as the time required for the fan motor to make a predetermined rotation. Combustion device.   When the 2M correction pulses include K pulses having a time width less than the predetermined time, the rotation number detector may include a pulse train composed of consecutive N + 2M pulses before or after the pulse train. The number of rotations of the fan motor is detected by setting the time width of the pulse train composed of a total of N + 2M + 2K continuous pulses including the subsequent 2K correction pulses as the time required for the fan motor to make a predetermined rotation. The combustion apparatus according to claim 1. A fan motor for supplying combustion air;
A sensor that outputs a total of N high level pulses and low level pulses during normal operation while the fan motor rotates a predetermined amount;
A rotational speed detector for detecting the rotational speed of the fan motor based on a pulse output from the sensor;
A controller that performs combustion control including rotational speed control of the fan motor based on the rotational speed detected by the rotational speed detector;
A combustion apparatus comprising:
The rotation speed detector includes a pulse width of a total of N + 2P consecutive pulses obtained by adding 2P correction pulses preceding or following the pulse train including N consecutive pulses to the pulse train including N consecutive pulses. , As the time required for the fan motor to make a predetermined rotation, the number of rotations of the fan motor is detected,
The combustion apparatus, wherein P is the number of pulses having a time width less than a predetermined time included in the pulse train composed of the N + 2P consecutive pulses. The rotational speed detector determines whether or not the difference between the target rotational speed of the fan motor and the detected rotational speed is within a predetermined rotational speed range, and is within the predetermined rotational speed range; Furthermore, when the rotation speed detected this time fluctuates more than a predetermined rotation speed from the rotation speed detected last time, the rotation speed detected last time is regarded as the rotation speed detected this time. The combustion apparatus as described in.

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