JP2003247720A - Control device for combustor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of an unpleasant feeling given to a user when a failure of an ignitor precludes the formation of flames with igniting operation, because a fuel supplied to a burner by a fuel pump is continuously released as white smokes into air for a preset time after starting the igniting operation. <P>SOLUTION: This control device for a combustor comprises: a burner 1; a flame rod 4; flame current detecting means 5 for detecting a flame current; counting means 6 for counting a time after starting igniting operation; ignition determining means 7 for determining ignition/non-ignition; and ignition determination level switching means 8. Before the counting means 6 counts a second preset time T<SB>2</SB>shorter than a first preset time T<SB>1</SB>, even when the flame current I<SB>f</SB>detected by the flame current detecting means 5 does not reach at least a second ignition determination level I<SB>2</SB>lower than a first ignition determination level I<SB>1</SB>as an ignition determination level for generally determining ignition/non- ignition, the non-ignition is determined and combustion operation is stopped at this time. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a combustor such as an oil fan heater.

[0002]

2. Description of the Related Art Conventionally, in a control device for a combustor, if a flame is not formed due to a failure of the ignition device, a failure of a fuel pump or a blower for combustion, etc., even if a predetermined time has elapsed from the start of ignition operation, a fuel is burned. Since the fuel supplied to the burner by the pump will continue to be released into the air as white smoke (vaporized gas), a flame rod is installed near the burner to prevent the flame current flowing between the burner and the flame rod. Ignition / non-ignition is determined by detection, and if the detected flame current value does not reach the ignition determination level or more by the predetermined time from the start of ignition operation, it is determined to be non-ignition and combustion. I was trying to stop the operation.

However, if the ignition determination level is lowered to a level at which it is possible to determine the presence or absence of flame, for example,
After the ignition operation starts, even if the air-fuel ratio collapses due to a failure of the fuel pump or the blower for combustion, etc. and the flame condition such as extreme red fire combustion or lifting combustion is significantly deteriorated, it is judged as ignition and the odor The user will feel uncomfortable due to increased strength. Therefore, the ignition determination level must be set to a level at which stable combustion can be obtained after ignition so that it is not determined to be ignition when the flame condition such as extreme red-fire combustion or lifting combustion is extremely poor. is there. Further, the control device of the combustor is provided with a flame current misfire determination level for stopping the combustion when the flame disappears or the flame condition significantly deteriorates during combustion. Therefore, the ignition determination level needs to be set to a higher level including a margin than the misfire determination level so that the misfire determination is not immediately caused by the fluctuation of the flame current value after ignition.

On the other hand, since the flame current value gradually increases as the flame grows after the flame is formed, it takes some time from the start of ignition for the flame current value to satisfy the above-mentioned ignition determination level. It will be. Therefore, it is necessary to set the time for performing the ignition determination to a time (for example, 15 seconds) sufficient for the flame current value to satisfy the above-described ignition determination level.

FIG. 4 shows a conventional burner controller.
By the flame current detected through the frame rod,
It is explanatory drawing which shows a mode that a fire / non-ignition is judged, flame current
Value I _fIs the ignition determination time T₁Ignition judgment level I within₁To
If it exceeds, it is judged as ignition and shifts to normal combustion control.
And flame current value I_fIs the ignition determination time T₁Ignition judgment within
Bell I₁If it does not exceed the
The firing operation is stopped. At this time, the ignition determination level I₁
Is a flame condition, such as extreme red-fire burning or lifting burning
If is markedly worse, it will not be judged as ignition
Combustion at a level where stable combustion can be obtained after ignition
The flame disappeared or the flame condition became significantly worse.
In case of misfire,
It is set to a higher level including the margin,
Ignition determination time T₁To meet this ignition determination level
It is set to a sufficient time (for example, 15 seconds).

[0006]

However, in the above-mentioned conventional method, when the flame is not formed even if the ignition operation is performed due to the failure of the ignition device or the like, from the start of the ignition operation to the ignition determination time T ₁ . Since the fuel supplied to the burner by the fuel pump continues to be released into the air as white smoke,
This will give the user discomfort.

The present invention has been made in order to solve the above-mentioned problems, and when a flame is not formed even if an ignition operation is performed due to a failure of an ignition device or the like, the time is shorter than usual. Combustion that can stop the combustion operation, reduce the time and amount of fuel supplied to the burner by the fuel pump to the air as white smoke, and reduce the discomfort of the user for white smoke. The purpose is to provide a control device.

[0008]

A combustor control apparatus according to the present invention includes a burner for burning fuel, a frame rod disposed near the burner, and a combustion flame between the burner and the frame rod. A flame current detecting means for detecting a flame current flowing therethrough, a time measuring means for measuring the time from the start of the ignition operation, and an ignition judging means for judging ignition / non-ignition, wherein the ignition judging means is the time measuring means. When the flame current detected by the flame current detecting means is equal to or higher than the first ignition determination level until the first predetermined time is measured, it is determined as ignition and the combustion operation is continued, In a combustor control device configured to determine non-ignition and stop the combustion operation when the first ignition determination level is not equal to or higher than the first ignition determination level, the ignition determination means includes the timekeeping means and the first timing determination means.
If the flame current detected by the flame current detecting means is equal to or higher than the second ignition determination level lower than the first ignition determination level until the second predetermined time shorter than the predetermined time is measured. Even when there is no ignition, it is determined that non-ignition has occurred and the combustion operation is stopped at that time.

The combustor controller according to the present invention is
A burner that burns fuel, a frame rod arranged in the vicinity of this burner, a flame current detection unit that detects a flame current flowing through the combustion flame between the burner and the frame rod, and a time from the start of ignition operation. And a firing determination means for determining ignition / non-firing, the ignition determination means is configured to detect the flame current by the flame current detection means before the timing means measures a first predetermined time. If the detected flame current is above the first ignition determination level, it is determined to be ignition and the combustion operation is continued, and if it is not above the first ignition determination level, it is determined to be non-ignition. In a control device for a combustor configured to stop a combustion operation, an ignition determination level switching means for switching a level for determining ignition / non-ignition is provided. Until the second predetermined time shorter than the first predetermined time is measured, the second ignition determination level lower than the first ignition determination level is switched to, and the time measuring means is configured to perform the second predetermined determination. During the period from the time until the first predetermined time is measured, the first ignition determination level is switched.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. Embodiment 1 of the present invention will be described below with reference to the drawings. 1 is a block diagram of a control device for a combustor showing a first embodiment of the present invention. In FIG. 1, 1 is a burner, 2 is a fuel pump for supplying fuel to the burner, 3 is a blower for combustion that supplies combustion air to the burner 1, 4 is a frame rod arranged near the burner 1, and 5 is a frame rod. The flame current detecting means for detecting the flame current flowing through the combustion flame between the burner 1 and the flame rod 4, 6 is the time measuring means for measuring the time from the start of driving the fuel pump 2, and 7 is the flame current detecting means 5. Ignition determination means for determining ignition / non-ignition, 8 is a second ignition determination level I ₂ which is set to a lower determination level used by the ignition determination means 7 in the ignition determination as long as the presence or absence of flame can be determined. first ignition determination level switching means for switching the ignition judgment level I ₁ the second ignition judgment level stable combustion after higher ignition than is set to a high level to be obtained, 9 fuel pump 2 and the combustion air blower Combustion control unit for controlling the, 10 timer means 6, ignition determination means 7 includes a combustion control unit 9 is a microcomputer which stores a program for controlling the combustion of the burner 1.

Next, the operation of the control device according to the first embodiment described above will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of the first embodiment of the control device according to the present invention.

First, when the operation switch (not shown) is turned on, and thereafter the ignition operation is started, the combustion control unit 9
Starts the drive control of the fuel pump 2 (step 2
0). On the other hand, the microcomputer 10 is the fuel pump 2
The time from the start of driving is measured by the time measuring means 6, and it is determined whether or not the second ignition determination time T ₂ has elapsed (step 21). Until the second ignition determination time T ₂ elapses, the ignition determination means 7 determines whether or not the flame current value _If detected by the flame current detection means is equal to or higher than the second ignition determination level I _2. (Step 2
2), the ignition determination is repeated until it is determined that the second ignition determination level I ₂ or more (I _f ≧ I ₂ ). At this time,
If it is not determined that the second ignition determination level I ₂ or more (I _f ≧ I ₂ ) is reached even after the second ignition determination time T ₂ has elapsed, it is determined that the ignition is not performed and the combustion operation is stopped ( Step 23). Next, if it is determined that the second ignition determination level I ₂ or more (I _f ≧ I ₂ ) is reached before the second ignition determination time T ₂ elapses, it is determined to be ignition and the ignition determination level is determined. The ignition level / non-ignition level determined by the switching means 8 is set to the second level.
Ignition determination level I ₂ to the first ignition determination level I
₁ (I ₁ > I ₂ ) and the microcomputer 1
For 0, it is determined whether the first ignition determination time T ₁ (T ₁ > T ₂ ) has elapsed (step 25). Until passage of T ₁ first ignition determination time, the flame current is detected by the flame current sensing means value I _f the first ignition determination level I
It is judged by the ignition judging means 7 whether it is ₁ or more (step 26), and the ignition judgment is repeated until it is judged that the first ignition judgment level I ₁ or more (I _f ≧ I ₁ ). At this time, if it is not determined that the first ignition determination level I ₁ or more (I _f ≧ I ₁ ) is reached even after the first ignition determination time T ₁ , the non-ignition is determined and the combustion is stopped. (Step 27). Here, the first ignition determination time T ₁
The first ignition determination level I ₁ or higher (I
_When it is determined that _f ≧ I ₁ ) is determined, ignition is determined, the ignition operation is terminated, and the combustion operation is continued (step 2
8).

FIG. 3 is an explanatory diagram showing the relationship between the flame current value _If detected by the flame current detecting means 5 according to the first embodiment, the ignition determination level, and the ignition determination time.

[0014] In FIG. 3, the ignition judgment level of flame current value I _f to be detected by the previously described flame current detector 5 from the driving start fuel pump 2 second ignition determination time T
_{The second} ignition determination level I ₂ is up to ₂ and the first ignition determination level I ₁ is up to the first ignition determination time T ₁ . Here, the second ignition determination level I ₂ is set lower than the _first ignition determination level I ₁ which is set to a level at which stable combustion is obtained after ignition, as long as the presence or absence of flame can be determined. Therefore, the second ignition determination time T
₂ is a time sufficient for forming a flame (for example, 5 seconds), as compared with a _first ignition determination time T ₁ (for example, 15 seconds) which is a time sufficient for achieving a level of stable combustion. ) Has been shortened.

As described above, according to the first embodiment,
The second ignition determination level I ₂ is set to a level that can determine the presence or absence of flame, and the second ignition determination time T ₂ is set to a time sufficient to form a flame (for example, 5 seconds).
The ignition determination level I ₁ is set to a level which ignites after stable combustion is obtained, sufficient time to T ₁ first ignition determination time to fill the ignition judgment level I ₁ of the first (e.g., 1
5 seconds), and if the flame current value _If does not satisfy the second ignition determination level I ₂ by the second ignition determination time T ₂ , or until the first ignition determination time T _1. If the first ignition determination level I ₁ is not satisfied, it is determined that the ignition is not performed, the combustion operation is stopped, and the second ignition determination time T
_{The second} ignition determination level I ₂ is satisfied by ₂
If the first ignition determination level I ₁ is satisfied by the ignition determination time T ₁ of No. 1, it is determined that ignition has occurred and combustion is continued. When not formed at all, the combustion operation is stopped within a short time (for example, 5 seconds) up to the _second ignition determination time T _2, so that the emission time of white smoke or the like can be shortened, and
When the flame condition such as extreme red-fire combustion or lifting combustion is remarkably deteriorated, the ignition is not determined as in the conventional device, so that stable combustion can be obtained after the ignition.

[0016]

As described above, according to the present invention, the combustion operation is stopped in a short time when the flame is not formed even if the ignition operation is performed due to the failure of the ignition device or the like. The time can be shortened, and if the flame condition is extremely bad such as extreme red-fire combustion or lifting combustion, it is not judged as ignition like the conventional device, so stable combustion is obtained after ignition. You can

[Brief description of drawings]

FIG. 1 is a block diagram of a combustor controller according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the combustor control device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a relationship between a flame current value, an ignition determination level, and an ignition determination time of the combustor control device according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a relationship between a flame current value, an ignition determination level, and an ignition determination time of a conventional control device for a combustor.

[Explanation of symbols]

1 burner, 2 fuel pump, 3 blower for combustion, 4
Frame rod, 5 flame current detection means, 6 timing means, 7
Ignition determination means, 8 Ignition determination level switching means, 9 Combustion control section, 10 Microcomputer.

Claims (2)

[Claims] 1. A burner for burning fuel, a frame rod arranged in the vicinity of the burner, a flame current detecting means for detecting a flame current flowing between the burner and the frame rod through a combustion flame, and ignition. It comprises a time counting means for counting the time from the start of the operation, and an ignition determination means for determining ignition / non-ignition, wherein the ignition determination means is the time until the time counting means measures the first predetermined time. When the flame current detected by the flame current detection means is equal to or higher than the first ignition determination level, it is determined that ignition has occurred and the combustion operation is continued,
When the ignition determination level is not equal to or higher than the ignition determination level, in the control device of the combustor that is determined to be non-ignition and stops the combustion operation, the ignition determination means, the timing means,
A second ignition determination level at which the flame current detected by the flame current detection means is lower than the first ignition determination level until a second predetermined time shorter than the first predetermined time is measured. A combustor control device characterized in that even if the above does not occur, it is determined that non-ignition has occurred and the combustion operation is stopped at that time. 2. A burner for burning fuel, a frame rod arranged in the vicinity of the burner, a flame current detecting means for detecting a flame current flowing between the burner and the frame rod through a combustion flame, and ignition. It comprises a time counting means for counting the time from the start of the operation, and an ignition determination means for determining ignition / non-ignition, wherein the ignition determination means is the time until the time counting means measures the first predetermined time. When the flame current detected by the flame current detecting means is equal to or higher than the first ignition determination level, it is determined to be ignition and the combustion operation is continued. When the flame current is not equal to or higher than the first ignition determination level, In a control device for a combustor that is determined to be ignited and stops the combustion operation, an ignition determination level switching means for switching a level for determining ignition / non-ignition is provided. The clocking means switches to a second ignition determination level lower than the first ignition determination level until the second predetermined time shorter than the first predetermined time is clocked, and the timing means, A control device for a combustor, wherein the control is switched to the first ignition determination level during the period from the second predetermined time until the first predetermined time is measured.