JP3588197B2 - Water heater - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement of a hot water heater typified by a single function hot water heater or a multifunctional oil hot water heater such as hot water and reheating.
[0002]
[Prior art]
In this type of conventional water heater, in order to control the combustion of the combustion equipment in accordance with the state of the flame, for example, the ignition and extinction of a burner of a combustion device as disclosed in Japanese Patent Publication No. 5-7608 are measured. And a control device employing an optical flame detecting device for detecting an ion current flowing in a combustion flame of a burner and a burner body as disclosed in Japanese Patent Publication No. 4-54847. There is proposed a device for controlling a combustion device based on a detection value taken into the device. The state of the flame is confirmed by comparing the detection results (that is, detection values) of these detection devices with two or one predetermined reference value.
[0003]
[Problems to be solved by the invention]
However, when the air-fuel ratio, the surrounding environment, and the like change, the size, color, and temperature (that is, the state of the flame) of the flame formed on the burner vary according to the change. The detection values of the detection devices disclosed in these publications also change according to the state of the flame. For this reason, if the misfire determination level is set to one for each sensor, there is a problem in that accurate flame state detection cannot be performed according to changes in the surrounding environment. On the other hand, even if the detection device and the control means can determine the misfire, immediately after the misfire, the fuel supply equipment such as the fuel pump and the solenoid valve does not operate normally because the temperature of the burner heated by the flame is high. In the case of an abnormality such that fuel continues to be supplied afterwards, the continuously supplied vaporized fuel ignites again at the burner temperature, and a flame is detected after a misfire, or the surrounding of the burner is detected by flame during normal combustion (for example, combustion). There is also a problem that a so-called pseudo-flame detection, in which the detector detects light and detects the presence of a flame even without a flame due to the temperature rise or reddening due to the heating, is performed, so that a misfire cannot be determined indefinitely. Was. Due to re-ignition immediately after this misfiring or misfiring not being detected due to the detection of a simulated flame, misfiring cannot be confirmed even though combustion has actually stopped, so if the next ignition instruction is given, it is not possible to promptly shift to the ignition sequence. The amount of hot water (that is, dead water) that is not heated tends to be large, and there has been a problem that the hot water supply characteristics are poor.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described facts. By appropriately changing the determination level of the flame sensor according to the degree of change in the detection value of the flame sensor, it is possible to reliably detect misfire and to determine the time until ignition. It is an object of the present invention to provide a water heater with improved safety that can detect a simulated flame immediately after a misfire in order to shorten the time.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present invention has found that the above problem can be solved by appropriately changing the judgment level of the flame sensor according to the degree of change in the detection value of the flame sensor. Is completed.
[0006]
According to the first aspect of the present invention, a burner for heating a heat exchanger is ignited by appropriately operating an ignition device including an electromagnetic pump, an electromagnetic valve, and an ignition plug, and the presence or absence of a flame formed on the burner, the size of the burner, etc. A flame sensor for detecting a state of the flame; and control means for controlling the operation of the ignition device and other combustion equipment based on a detection value of a sensor group of the combustor such as the flame sensor to supply hot water at a desired temperature. In the water heater, the control means stores the detected value of the flame sensor during combustion as needed, determines that a misfire has occurred when the detected value of the flame sensor has changed to a reference misfire determination level, and sets a misfire determination level after the misfire determination. Is changed to the detection value + predetermined value, and then the process proceeds to a predetermined reignition operation.
[0008]
According to a second aspect of the present invention, in the water heater according to the first aspect, the control means is configured to automatically return to a standard misfire determination level after a fixed time after modifying and changing the misfire determination level. It is.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.
[0010]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a partially cutaway perspective view showing the entire configuration of a water heater according to an embodiment of the present invention, and FIG. 2 is a partially cutaway front view showing an installation state when the water heater is installed indoors. FIG. 3 is a flow chart for explaining the operation of changing the misfire determination level in the control means of the present invention; FIG. 4 is a flow chart for explaining the overall combustion operation in the control means of the present invention; FIG. 6 is a voltage waveform diagram schematically illustrating a change, particularly a level change operation.
[0011]
1 and 2, reference numeral 1 denotes a direct-pressure oil hot water heater, which is an embodiment of a hot water heater, and a heat exchanger 3 is fixed to a lower rear portion of a casing 2 serving as a main body of the hot water heater 1. A muffler 4 for silencing is connected to an upper portion of the heat exchanger 3, and a combustion device 5 including a burner 17 for heating the heat exchanger 3 in a lower portion on the front side inside the casing 2, and a combustion device taken in from an air supply pipe 7. A blower 6 for supplying the fuel to the fuel cell 5 and an electromagnetic pump 11 for supplying a liquid fuel to the combustion device 5 are housed therein.
[0012]
Further, the combustion device 5 is configured such that a liquid fuel spray nozzle 18, a spark plug 19, a burner 17 and the like are integrally accommodated in a hollow cylindrical burner tube 16, and the combustion device 5 has a distal end portion. Is attached to an outer wall (that is, a combustion cylinder 9) facing a combustion chamber 8 formed inside the heat source side heat exchanger 3. A control device 15 controls various operations of the combustion device 5, the blower 6, a circulating pump (not shown) and a controller remote controller.
[0013]
On the other hand, a finned pipe 12 having a plurality of fins for heat exchange is provided above the combustion chamber 8, and the combustion device 5 and the finned pipe 12 constitute a heating device for a water heater. The end of the upstream side (return pipe) of the finned pipe 12 constituting this heating device is connected to the outlet side of the use side heat exchanger installed in each room via the return port 10, a header and pipes not shown. Further, an end on the downstream side (hot water supply pipe) of the finned pipe 12 is connected to an inlet side of a use side heat exchanger installed in each room via a hot water outlet 13, a circulation pump, and a pipe. .
[0014]
The control device 15 incorporates control means (not shown) represented by a microcomputer (hereinafter simply referred to as a microcomputer) into which a program for controlling the entire combustion operation of the water heater of the present invention is input. Here, the outline of the control of the entire combustion operation of the water heater will be described with reference to FIGS.
[0015]
First, in FIG. 4, when an operation switch provided on a remote controller (not shown) for remotely controlling the water heater 1 is turned on, the operation lamps of the display unit of the remote controller and the main unit side display unit located near the control device 15 are turned on in step S1. The light is turned on, and it is determined in step S2 whether or not the amount of water is equal to or more than a predetermined amount (for example, the amount of twist of the faucet which controls the amount of water is 2.5 liters per minute). If so, it is determined in step S3 whether or not the burner 17 is burning on / off. If it is not burning on / off, the burner motor is turned on in step S5 and the process proceeds to step S6. It is determined in step S4 whether the OFF time has elapsed. If the OFF time has not elapsed, the process returns to step S2, and if it has elapsed, the process proceeds to step S5. .
[0016]
In step S6, it is determined whether or not the rotation speed of the burner motor is within a predetermined rotation speed (for example, the ignition rotation speed ± 150 rpm). If not, the determination time (for example, 45 seconds) of the burner rotation speed abnormality is made in step S7. It is determined whether or not the time has elapsed. If the time has elapsed, a display symbol E6 (this is referred to as an E6 error) indicating a burner rotation speed abnormality is displayed on the display unit in step S8, and the burner motor is turned off in step S9 to start. If the time has not elapsed, the process returns to step S6.
[0017]
If the rotation speed is within the predetermined rotation speed in step S6, it is determined in step S10 whether the burner motor has been operated after digestion, that is, during post-purge. If not during post-purge, the motor rotation speed is stabilized in step S11 (for example, 1 second). It is determined whether or not the time has elapsed. If the time has elapsed, the ignition operation is started in step S12, and the process proceeds to step S13, which is the main control sequence of the present invention, to detect the presence or absence of a simulated flame. If it is, the process returns to step S6.
[0018]
The detection sequence of the presence or absence of the simulated flame performed in step S13 is a process as shown in FIG. In FIG. 3, it is determined in step S61 whether or not the detection of the presence or absence of a pseudo flame during the combustion mode (ie, the burner 17 is performing normal combustion or ON / OFF combustion) is performed. If not, it is determined in step S62 whether or not the time of the switching timer for measuring the limit time (for example, 60 seconds) for changing the pseudo flame detection level (pseudo flame determination voltage) VGL has elapsed. For example, the process returns to step S61 (that is, step S13), and after a lapse of time, in step S63, the simulated flame detection level (simulated flame judgment voltage) VGL is changed to the standard simulated flame detection level (standard simulated flame judgment voltage) VRF (for example, 2.5 volts). ), And returns to step S61 (that is, step S13).
[0019]
If it is determined in step S61 that there is a pseudo flame in the combustion mode, a pseudo flame detection level (pseudo flame determination voltage) VGL is set in step S64 to the flame sensor output (ie, current flame detection voltage) VNL stored during combustion. Is changed to a value obtained by adding the additional voltage (for example, 0.04 volts) VDF, the switching timer is reset in step S65, and the process returns to step S61 (that is, step S13). Here, the detection of the presence or absence of the simulated flame in the combustion mode means determining the flame sensor output after the misfire is determined once in a sequence described later. Of course, it is determined that there is no simulated flame in the combustion mode.
[0020]
In this manner, when the flame sensor output rises above a certain width or a certain value (2.5 volts in this case) according to the degree of change of the detection value of the flame sensor during combustion, it is determined that a misfire has occurred. After the misfire is determined, the pseudo flame detection operation is started, and the flame detection level is automatically corrected and changed to a value obtained by adding the added value VDF to the last stored numerical value VNL during normal combustion. Compared with the conventional pseudo-flame detection method in which the pseudo-flame detection method is fixed to a fixed value only, the pseudo-flame judgment accuracy is improved, and the accurate pseudo-flame judgment according to the situation change is enabled.
[0021]
Further, the detected value of the flame sensor during combustion is stored as needed, and it is determined that a misfire has occurred when the detected value of the flame sensor changes to a reference misfire determination level (here, a standard pseudo-flame determination voltage = 2.5 volts). After the misfire determination, the level of the misfire determination is changed to the above-mentioned detection value + predetermined value, and then the process proceeds to a predetermined re-ignition operation. Even if a pseudo-flame occurs due to a change in the flame, it can be determined that ignition is not occurring, and it is possible to reliably determine misfire. Furthermore, even if a simulated flame occurs immediately after a misfire, the simulated flame can be confirmed as a simulated flame due to a change in the level of the simulated flame judgment, and the time until ignition after the misfire confirmation can be shortened. Suppression of water death due to detection delay, improvement of tapping characteristics and improvement of determination accuracy were achieved, and safety as a water heater was improved.
[0022]
In addition, since the detection of the simulated flame after the detection of the misfire ends in a certain time, the corrected misfire level is returned to the standard misfire determination level after a certain time slightly longer than the certain time (here, the set time of the switching timer). Thus, if there is no change in the detected value after the return, it can be determined that the sensor has failed, so that the failure of the flame sensor can be detected. In the event of a sensor failure, a fail-safe operation can be performed to provide a more excellent water heater, and the safety as a combustion device is further improved.
[0023]
Returning to FIG. 4, if there is a simulated flame in step S13, it is determined in step S14 whether or not the time of the switching timer has elapsed. If the time has not elapsed, the process returns to step S13. Displays a display symbol E3 (this is called an E3 error) indicating the detection (generation) of the pseudo-flame on the display unit, stops the ignition operation in step S16, performs the burner motor OFF processing in step S17, and returns to the start.
[0024]
If there is no simulated flame in step S13, it is determined in step S18 whether or not the detection time of the flame sensor (for example, 0.5 seconds) has elapsed. If the time has not elapsed, the process returns to step S13. In step S19, the electromagnetic valve and the electromagnetic pump 11 are turned on. In step S20, the presence or absence of a flame is determined from the voltage detected by the flame sensor. If it is determined that there is no flame, in step S21, is a retry time (for example, 5 seconds) elapsed? Steps S20 and S21 are repeated until 5 seconds have elapsed, and if 5 seconds have elapsed, the electromagnetic valve and the electromagnetic pump 11 are turned off in step S22, and the ignition operation is stopped in step S23 and the ignition is stopped. The counter value for counting the number of times of ignition is incremented or decremented by one to prepare for a retry operation, and the process proceeds to step S24.
[0025]
In step S24, it is determined whether or not the number of misfires by the counter is the number of misfire determinations (for example, twice). If not, it is determined in step S25 whether or not the operation stabilization time (for example, 10 seconds) has elapsed. Then, the process waits until 10 seconds elapse, and returns to step S6 when 10 seconds elapse. If the number of misfirings is two in step S25, a display symbol E1 (this is referred to as an E1 error) indicating two consecutive misfirings (that is, a misfiring) is displayed in step S26. Is performed.
[0026]
In step S28, it is determined whether the output sampling time of the flame sensor (for example, 200 msec) has elapsed. Steps S20 and S28 are repeated until the sampling time has elapsed. The presence or absence of a flame is determined from the detected voltage. If it is determined in step S29 that there is no flame, the process proceeds to step S34. If it is determined that there is a flame, the combustion indicator lamp on the display unit indicating that combustion is in progress is turned on in step S30, and the standby time is set in step S31. It is determined whether or not (for example, 1.5 seconds) has elapsed, and the operations of step S29, step S30, and step S31 are repeated until the time has elapsed. After the time has elapsed, the ignition operation is stopped in step S32, and in step S33. The presence or absence of a flame is determined from the voltage detected by the flame sensor. If there is no flame, the process proceeds to step S34. If there is a flame, the process proceeds to step S41. However, the determination of the presence or absence of a flame in step S33 is a determination operation for detecting the state of the flame after the end of the ignition operation, and has a different meaning from the previous two determinations.
[0027]
In step S34, it is determined whether or not the detection time (for example, 0.5 seconds) of the flame sensor has elapsed. If the time has not elapsed, the process returns to step S29. The pump 11 is turned on, the combustion indicator lamp on the display unit is turned off in step S36, and it is determined in step S37 whether or not the time since the start of detecting the presence or absence of flame is less than a predetermined time (for example, one minute). If the time is longer than the predetermined time, the process proceeds to step S25. If the time is less than the predetermined time, it is determined in step S38 whether the number of misfirings within the predetermined time is the number of fire extinguishing determinations (for example, five). Move to S25,
If it has been fired five times, a display symbol E2 (this is referred to as an E2 error) indicating a so-called halfway misfire that is not fired even if a predetermined ignition retry is performed, although the ignition is incomplete even though a predetermined ignition retry is performed, and the post-purge time ( After elapse of 5 minutes, for example, the burner motor is turned off and the operation returns to the start.
[0028]
In step S41 in which it is determined that there is a flame in step S33, the amount of twist of the faucet is set to 1 per minute as a predetermined water amount for stopping the combustion (that is, a value indicating that the faucet has been operated to the closing side smaller than the previous predetermined amount). (1.5 liters) or less. If it is 1.5 liters or less, the combustion OFF process from step S50 is performed. If it exceeds 1.5 liters, it is determined whether or not the operation switch has been turned off in step S42. Is determined, and if it is turned off, the combustion OFF process from step S50 is performed. If it is not OFF, it is determined in step S43 whether or not the burner 17 is performing ON / OFF combustion.
[0029]
If the ON / OFF combustion is not being performed in step S43, the process returns to step S33. If the ON / OFF combustion is being performed, it is determined in step S44 whether the ON time has elapsed. If the ON time has not elapsed, step S33 is performed. If the ON time has elapsed, both the electromagnetic valve and the electromagnetic pump 11 are turned off in step S45, the combustion indicator lamp on the display unit is turned off in step S46, and the process returns to step S2.
[0030]
On the other hand, when step S50 of the combustion OFF process is started, both the electromagnetic valve and the electromagnetic pump 11 are turned off in step S51, the combustion indicator lamp on the display unit is turned off in step S52, and the post-purge time (for example, 5 minutes) in step S53. After the elapse, the burner motor is turned off and the operation returns to the start.
[0031]
In the above description, an example in which an optical sensor is used as the flame sensor has been described. However, the flame sensor is not limited to this example, and may be a sensor based on a frame current or another sensor.
[0033]
【The invention's effect】
According to the water heater of the first aspect, the detected value of the flame sensor during combustion is stored as needed, and when the detected value of the flame sensor changes to a certain reference misfire determination level, it is determined that a misfire has occurred. Is changed to the detection value + predetermined value and then to a predetermined re-ignition operation. Therefore, once a misfire is determined, the level of the misfire determination changes and a pseudo flame is generated. Even if it occurs, it can be determined that ignition does not occur, and it is possible to reliably determine misfire. Also, even if a simulated flame immediately after a misfire occurs, the simulated flame can be confirmed as a simulated flame due to a change in the level of misfire determination, and the time until ignition after a conventional misfire confirmation can be shortened. It is possible to suppress the generation of water, improve the tapping characteristics, and improve the judgment accuracy, thereby improving the safety as a water heater.
[0034]
According to the water heater of the second aspect, since the detection of the simulated flame after the detection of the misfire ends in a certain time, the corrected misfire level is returned to the standard misfire determination level after a certain time slightly longer than the certain time. If there is no change in the detected value after the return, it can be determined that the sensor has failed, so that the failure of the flame sensor can be detected. Correction according to the characteristics becomes possible, and when the sensor is abnormal, a fail-safe operation can provide a more excellent water heater, thereby further improving the safety as a combustion device.
[Brief description of the drawings]
FIG. 1 is a partially cutaway perspective view showing the entire configuration of a water heater according to an embodiment of the present invention.
FIG. 2 is a front cross-sectional view of a partially cut-away state showing an installation state when the water heater is installed indoors.
FIG. 3 is a flowchart illustrating an operation for changing a misfire level in a control unit of the present invention.
FIG. 4 is a flowchart schematically illustrating the overall combustion operation of the control means of the present invention.
FIG. 5 is a voltage waveform diagram schematically illustrating an output change of a flame sensor, particularly a level change operation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hot water supply device 3 Heat exchanger 5 Combustion device 11 Electromagnetic pump 15 Control device (control means)
17 Burner 19 Spark plug

Claims (2)

A flame sensor for igniting a burner for heating the heat exchanger by appropriately operating an ignition device comprising an electromagnetic pump, a solenoid valve, and an ignition plug, and detecting the presence or absence of a flame formed on the burner and the state of a large or small flame; Control means for controlling the operation of the igniter and other combustion equipment based on a detection value of a sensor group of a combustor such as a flame sensor to supply hot water at a desired temperature. The detected value of the flame sensor during the storage is stored as needed, and when the detected value of the flame sensor changes to a reference misfire judgment level (a predetermined judgment value), it is judged that a misfire has occurred, and after the misfire judgment, the misfire judgment level is detected. A water heater characterized by shifting to a predetermined re-ignition operation after changing to a value + a predetermined value . 2. The water heater according to claim 1, wherein the control unit automatically returns to the reference misfire determination level after a predetermined time after correcting and changing the misfire determination level . 3.

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