JPH05240424A - Method for judging presence or absence of flame in combustion equipment - Google Patents

Abstract

PURPOSE:To enable an accurate judgement of presence or absence of flame to be carried out for a long period of time by a method wherein a result of sensing a flame sensor, an ignition judgement reference value and a flame diminishing judgement reference value are compared to each other to judge the presence or absence of the ignition and each of the judgement reference values is changed in response to an aging variation of the detected value of the flame sensing sensor. CONSTITUTION:In a oil hot water feeder including a combustion boiler 10 having an instantaneous heating heat exchanger 11 therein and a burner 20 having an atomization nozzle 21 for fuel oil and a blower 22 therein, the burner 20 is provided with a Cds flame sensing sensor 23 and then a hot water feeding operation control including ignition and flame diminishing under an operation of the controller 30 in response to its output signal and an instruction from a remote controller 40. In the case that the presence or absence of the ignition under the instruction of combustion and the presence or absence of the flame diminishing is judged, the controller 30 compares the detected value of the flame sensing sensor 23 with the stored ignition judgement reference value and the flame diminishing judgement reference value and then each of the judgement reference values is changed in response to the aging variation of the detected value of the flame sensing sensor 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining the presence or absence of flame in a combustor such as an oil water heater.

[0002]

2. Description of the Related Art Conventionally, in a combustor such as an oil water heater, the presence or absence of ignition or extinguishing associated with the burning operation of the burner is determined using a flame detection sensor such as a CdS flame detection sensor. .. And in that case, conventionally, the detection value of the flame detection sensor is compared with one reference value fixedly set in advance,
The size was used to determine whether it was in an ignition state or a fire extinguishing state.

[0003]

However, in a combustor, particularly in the case where combustion is performed with a large combustion capacity, a high temperature part is locally generated in the combustion can body, and after that part of combustion is stopped. For a while, it tends to shine brightly, and even if it is covered with a heat insulating material to prevent the occurrence of local high temperature parts, the part of the heat insulating material tends to stay bright for a while even after the end of combustion. was there. as a result,
The brightness at the time of ignition and the brightness at the time of extinguishing do not change much, so that there is a drawback that the presence or absence of ignition or extinguishing cannot be reliably determined even when compared with one fixed reference value as described above. In particular, if there is a variation in the performance of the flame sensor itself, or if there is a change in detection sensitivity over time due to soot, dust, etc.,
There is a problem that it is more difficult to accurately determine whether the ignition or extinguishing is to occur.

Therefore, the present invention solves the drawbacks of the above-described conventional flame presence / absence determination method in the combustor, and the difference in the brightness as the background in the combustion can body at the start of combustion and the stop of combustion, and the flame detection sensor The controller has a learning function to give an appropriate judgment reference value in a form that follows variations in performance, changes in the performance of the flame detection sensor over time, etc. The purpose is to provide a method for determining the presence or absence of flame in a container.

[0005]

In order to achieve the above object, the method of the present invention comprises a detection value detected by a flame detection sensor and a controller for the presence or absence of ignition based on a combustion command and the presence or absence of extinction based on a fire extinguishing command. A method for determining the presence or absence of flame in a combustor configured to make a determination by comparing the ignition determination reference value and the extinguishing determination reference value stored in
It is characterized in that the ignition determination reference value and the extinguishing determination reference value stored in the controller are changed in response to the secular change in the value detected by the flame detection sensor.

[0006]

[Operation] When ignition is to be started based on the combustion command,
The ignition detection reference value stored in the controller is compared with the detection value of the flame detection sensor to make a determination. on the other hand,
When the fire is to be extinguished from the combustion state based on the fire extinguishing command, the detection value of the flame detection sensor is compared with the separately stored fire extinguishing determination reference value for determination. That is, two reference values are set in consideration of the difference in the state of the inside of the combustion can (combustion chamber) when the ignition is performed from the state where the combustion is not yet performed and when the fire is extinguished after the combustion is performed. This makes it possible to more accurately determine ignition and extinguishment. Further, since the detection sensitivity of the flame detection sensor gradually changes with the passage of time, the accuracy of determination gradually deteriorates as it is, but in the present invention, the change in detection sensitivity of the flame detection sensor with time, that is, Since the ignition determination reference value and the extinguishing determination reference value are modified and changed in a form corresponding to the secular change, accurate determination can be performed for a relatively long period of time.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a schematic configuration diagram of a gun type oil water heater that implements the method of the present invention, FIG. 2 is an electric circuit diagram showing the relationship between a flame detection sensor and a microcomputer incorporated in a controller, and FIG.
Is a flow chart for determining ignition and extinguishing by a controller, FIG. 4 is a flow chart of a subroutine for determining an ignition determination reference value and an extinguishing determination reference value, and FIG. 5 is a time chart showing a temporal change in detection sensitivity of the flame detection sensor.

The oil water heater has a combustion can body 10, a burner 20, a controller 30, and a remote controller 40. An instant heating type heat exchanger 11 is provided in the combustion can body 10. Further, the lower inner wall of the combustion can body 10 is covered with a heat insulating material 12. The burner 20 includes a fuel oil spray nozzle 21 and a blower 22.
Is provided. Also, a CdS flame detection sensor 23 is provided. The controller 30 has a microcomputer 31 built-in, receives commands from the remote controller 40 and information from other sensors,
Issue operation control commands for hot water supply to each part of the water heater. Then, as a part of the operation control, the controller 30 performs ignition determination and extinction determination of the burner 20 combustion.

The value detected by the flame detection sensor 23 is A / D converted and input into the microcomputer 31 of the controller 30 via an operational amplifier, as shown in FIG. controller
At 30, the input value from the flame detection sensor 23 is compared with the previously stored ignition determination reference value or extinguishing determination reference value to determine the presence or absence of flame. This determination method is further illustrated in FIG.
The flow will be described. Now on the remote control 40,
When the operation switch of the oil water heater is turned on (S1), the hot water supply lan (not shown) is opened, and when a flow exceeding the minimum working water amount is detected, a combustion command is issued by the controller 30 (S2). A series of ignition sequences is performed by this combustion command (S3). In the sequence, first, the pre-purge by the blower 22 and the spark by the ignition electrode rod (not shown) are performed. Then, a fuel supply electromagnetic pump (not shown) is turned on so that the petroleum fuel sprayed from the spray nozzle 21 is ignited by the spark of the ignition electrode rod.

In the ignition sequence, whether or not the ignition is actually performed is determined by comparing the digital conversion detection value X _H from the flame detection sensor 23 with the ignition determination reference value H stored in the microcomputer 31 of the controller 30. A determination is made (S4). In the detection by the flame detection sensor 23, when the CdS flame detection sensor is used, the higher the brightness, the smaller the resistance from the sensor, so that the A / D converted digital conversion detection value X _H is also detected. The higher the brightness, the smaller the value. That is, when the detected value X _H is less than or equal to the ignition determination reference value H (S
If yes in 4), it is determined that the ignition has occurred. Then, the detected value X _H at that time is stored as data in the microcomputer 31 (S5). Then, after that, when a fire extinguishing command is issued from the controller 30 by closing a hot water supply run (not shown) or the like (S6), the fire extinguishing operation is performed. When doing so compared to extinguish determination reference value L of storing digital conversion detection value X _L from the flame detection sensor 23 to the microcomputer 31 determines whether or not extinguishing is made (S7). And the digital conversion detection value X
_{If L} is greater than or equal to the fire extinguishing determination reference value L (Yes in S7), it is determined that the fire has been extinguished, and the detected value X _{L at} that time
Is stored in the microcomputer 31 as data (S8). When these operations are completed, the subroutine (S9) is executed and then S1 is executed.
Return to. In the case of NO in S4 (when it is determined that the ignition has not occurred), it is determined whether the ignition sequence has been repeated a certain number of times (for example, 3 times) (S10), and in the case of NO, the process returns to the ignition sequence (S3). .. If yes,
As the ignition failure, the safety operation is started, the ignition operation such as the fuel supply and the air blowing is stopped, and the operation is stopped (S13). The S
If the answer is No in 7 (if it is determined that the fire has not been extinguished), it is further determined whether a certain time has elapsed (S1
2) If the answer is NO, the determination in S7 is further continued. If the answer is YES, the fire is not fired properly and the operation is performed safely (S13).

How to set the ignition determination reference value H and the extinguishing determination reference value L will be further described with reference to the subroutine of FIG. 4 and FIG. Keep first determine an initial value L _O of the initial value H _O and extinguishing criterion ignition criterion advance (S20). Since this value can be obtained in advance by experiments or the like, an appropriate value for ignition determination and an appropriate value for fire extinguishing determination are used.
Next, the controller controls the digital conversion detection value X _HO from the flame detection sensor 23 when the water heater is first ignited and the digital conversion detection value X _LO from the flame detection sensor 23 when the water heater is first extinguished. It is stored in the microcomputer 31 of 30 (S21)

Then, the ignition detection value X _H obtained in S5 of FIG. 3 is averaged every fixed number of times N to calculate an average value _AV X _H. Similarly the extinguishing time detection value X _L averaged every predetermined number N,
The average value _{AV XL} is calculated (S22). The average value _AV X _H ,
_{When AV XL} is calculated, the absolute values of the differences between the average values _AV X _H and _{AV XL} and the initial detection values X _HO and X _LO are calculated,
It is determined whether or not the difference is less than or equal to the constant values A and B (S
23), in the case of yes, the difference ( _AV X _H −X _HO ), (
_AV X _L -X _LO) each ignition determination reference initial value H _O, new addition to extinguishing criterion initial value L _O ignition determination reference value H, the extinguishing determination reference value L (S24). If the absolute value of the difference exceeds the constant values A and B in S23, an alarm or the like is issued (S25).

The average values _AV X _H and _{AV XL} and the initial detection value X
_HO, the difference between the _{X LO (AV X H -X HO} ), (AV X L -X LO)
Shows how the detection sensitivity of the flame detection sensor 23 changes from the initial state over time (solid line indicated by X _H , solid line indicated by X _{L in} FIG. 5). Thus the ignition determination reference value H corresponds to the difference representing the status of the change, extinguishing determination reference value L also ignition determination reference initial value H _O, to vary in the same manner from the extinguishing criterion initial value L _O (S24)
By using the solid line indicated by H and the solid line indicated by L in FIG. 5, it is possible to provide appropriate ignition and extinction reference values H and L corresponding to changes over time (aging) in the sensitivity of the flame detection sensor 23. is there. Then the difference _{(AV X H -X HO),} (AV X L -X LO)
If the value becomes too large, the deterioration of the sensitivity of the flame detection sensor 23 is large, and an alarm is issued. The alarm allows the user to replace or clean the flame detection sensor 23 and restore the initial state.

[0014]

According to the method for judging the presence / absence of a flame in the combustor according to the first aspect of the present invention, the present invention has the above-mentioned structure and operation. Since the judgment is made by comparing the detection value detected by the flame detection sensor with the ignition judgment reference value and the extinguishment judgment reference value stored in the controller, the case where the ignition is started from the state where the combustion has not yet been made When the fire is extinguished after the combustion is performed, it is possible to more accurately determine the ignition and the extinction by using two reference values that are respectively suitable. Also, since the ignition judgment reference value and the extinction judgment reference value stored in the controller are changed in response to the secular change in the value detected by the flame detection sensor, it is possible to respond to the change over time in the detection sensitivity of the flame detection sensor, that is, the secular change. It is possible to correct and change the ignition judgment reference value and the extinguishment judgment reference value in the same manner, and it is possible to eliminate the influence of deterioration of the flame detection sensor, dust, and soot, and perform accurate judgment for a relatively long period of time. ..

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a gun type petroleum water heater in which the method of the present invention is carried out.

FIG. 2 is an electric circuit diagram showing a relationship between a flame detection sensor and a microcomputer incorporated in a controller.

FIG. 3 is a flowchart for determining whether ignition or extinguishing is performed by a controller.

FIG. 4 is a flowchart of a subroutine for determining an ignition determination reference value and an extinguishing determination reference value.

FIG. 5 is a time chart showing a temporal change in detection sensitivity of the flame detection sensor.

[Explanation of symbols] 10 Combustion can body 11 Heat exchanger 12 Insulation material 20 Burner 21 Spray nozzle 22 Blower 23 Flame detection sensor 30 Controller 31 Microcomputer 40 Remote control

Claims (1)

[Claims] 1. Comparing the presence or absence of ignition based on a combustion command and the presence or absence of extinguishment based on a fire extinguishing command with a detection value detected by a flame detection sensor and an ignition determination reference value and an extinction determination reference value stored in a controller, respectively. A method for determining the presence / absence of flame in a combustor, wherein the ignition determination reference value and the extinction determination reference value stored in the controller are changed in response to the secular change in the value detected by the flame detection sensor. A method for determining the presence or absence of a flame in a combustor, which comprises: