JP2019074291A - State determination device of flame rod - Google Patents

Abstract

To early detect an abnormal state of a flame rod, such as deterioration of insulation.SOLUTION: A state detection device of a flame rod causes a determination standard time storage unit 21-6 to store first determination standard time Tdmax defined as an upper limit side boundary value within a normal range, and second determination standard time TdH defined as an upper limit side boundary value within a regular range. The state detection device comprises an ignition delay determination unit 21-3. The ignition delay determination unit 21-3 is configured to, when ignition delay time Td counted by a timer 21-2 falls between the first determination standard time Tdmax and the second determination standard time TdH, determine that the flame rod is in a failure state.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a flame rod state determination device that detects the strength of a flame by an electric current flowing to an electrode rod inserted into the flame.

  Conventionally, as a combustion system, a combustion system provided with a combustion device provided with an igniter and a burner, and a combustion control device for controlling the operation of the combustion device according to a predetermined combustion sequence (for example, Patent Document 1).

  In this combustion system, the operation sequence from startup of the combustion device to steady-state combustion is defined as a combustion sequence. For example, "start check", "pre-purge", "wait for ignition", "pilot ignition", "pilot only", "main ignition", "main stable", and the like from the start of the combustion apparatus to the steady combustion Each combustion sequence is defined as "stationary combustion".

  Also, in this combustion system, the flame intensity of the burner is detected by the flame rod, and a flame detection signal from the flame rod (a signal indicating the flame intensity of the burner) is acquired as flame voltage VF, for example. From the value of VF, the presence or absence of a flame and the ignition abnormality are judged.

  For example, the time from the start of fuel supply to the burner (the start of combustion) to the determination that there is a flame (the time until the frame voltage VF reaches a predetermined voltage value) is monitored. If it is not determined, it is determined that misfire has occurred. If it is determined that the fuel is misfired, the combustion control device closes the safety shutoff valve to shut off the supply of fuel to the burner. That is, the combustion device is brought into the lockout state.

JP, 2011-208921, A

  However, in the conventional combustion system, when an abnormality occurs in the flame rod, the flame detection is not properly performed, and it is not determined that the flame is present despite the generation of the flame, and the combustion apparatus is locked out. The phenomenon of being considered a state sometimes occurred. Once the combustion device is locked out, it may take time to restart it, which may result in significant economic loss.

  It should be noted that if it is possible to detect at an early stage that an abnormality has occurred in the flame rod, it can be dealt with before the combustion device is put into a lockout state. You need to check the status regularly. In this case, it is not clear whether or not there is an abnormality in the flame rod. For this reason, it is necessary to periodically perform maintenance on items that do not actually have an abnormality and do not require maintenance, resulting in an increase in cost.

  In addition, as the abnormality of the frame rod, for example, insulation deterioration of the frame rod, rust of the frame rod, wiring insulation failure of the frame rod, contact failure, jumping into a spark to the frame rod, and the like can be considered.

  The present invention has been made to solve such a problem, and the object of the present invention is to provide a frame rod state determination device capable of early detecting an abnormality such as insulation deterioration of the frame rod. To provide.

  In order to achieve such an object, the present invention comprises an igniter (8) for igniting the burners (6, 7), and ultraviolet light generated by the flame of the burner as the flames are generated. A flame rod state determination device (21) for determining the state of a flame rod in a combustion system (100) having a flame rod (9) to be detected, wherein the flame strength detected by the flame rod is predetermined The flame presence / absence determination unit (21-1) configured to determine the flame presence when the first reference level (VFmin) is reached, and the flame presence / absence determination unit determines the flame presence from the start of combustion to the burner A timer (21-2) configured to measure the time until it is taken as an ignition delay time (Td), and a normal range in which the ignition delay time measured by the timer is predetermined In some but if deviated from the normal range, characterized in that it comprises first ignition delay determination unit frame rod is configured to determine to be in disordered state and (21-3).

  In the present invention, the flame presence / absence determining unit determines that the flame is present when the flame intensity detected by the flame rod reaches the first reference level. The timer measures the time from the start of combustion to the burner to the determination that there is a flame as an ignition delay time. The first ignition delay determination unit determines that the flame rod is in a malfunctioning state when the ignition delay timed by the timer is within the normal range but deviates from the normal range.

  For example, when the upper limit side boundary value of the normal range is determined as the first determination reference time, and the upper limit side boundary value of the normal range is determined as the second determination reference time, the timing measured by the timer is used. If the delay time is between the first determination reference time and the second determination reference time, it is determined that the flame rod is in a malfunctioning state.

  In the present invention, for example, when the insulation deterioration occurs in the frame rod and the degree of the insulation deterioration increases, the ignition delay time becomes longer. In this case, when the ignition delay time deviates from the normal range, it is determined that the flame rod is in a malfunctioning state. This makes it possible to detect the insulation deterioration of the flame rod early.

  In the present invention, the flame strength detected by the flame rod may be a flame voltage or flame current according to the flame strength. Furthermore, in the present invention, the start of combustion in the burner is the timing that is the starting point of the start of the measurement of the ignition delay time, and may be the timing of the start of fuel supply to the burner. It may be.

  In the above description, as an example, constituent elements on the drawing corresponding to constituent elements of the invention are indicated by reference numerals in parentheses.

  As described above, according to the present invention, when the ignition delay time measured by the timer is within the normal range but deviates from the normal range, it is determined that the flame rod is in a malfunctioning state. As a result, it is possible to early detect an abnormality such as insulation deterioration of the flame rod.

FIG. 1 is a time chart for explaining the time (ignition delay time Td) from the start of fuel supply to the burner (fuel valve opening) to the determination that there is a flame (ignition delay time Td). FIG. 2 is a view showing a normal, normal, abnormal, and malfunctioning range with respect to the ignition delay time Td. FIG. 3 is a diagram showing normal, normal, abnormal, and malfunctioning ranges for the frame voltage VF. FIG. 4 is a view showing an essential part of a combustion system including an embodiment of a flame rod state determination device according to the present invention. FIG. 5 is a diagram illustrating the configuration of the combustion system in which only the main burner is used. FIG. 6 is a time chart of the combustion sequence from startup of the combustion device to steady-state combustion. FIG. 7 is a functional block diagram of the main part of the frame rod state determination device of the first embodiment. FIG. 8 is a flowchart for explaining the function of each part of the frame rod state determination device of the first embodiment. FIG. 9 is a functional block diagram showing a modification of the frame rod state determination device of the first embodiment. FIG. 10 is a diagram showing the logic of state determination in the first embodiment and the modification of the first embodiment in comparison with the prior art. FIG. 11 is a functional block diagram of the main part of the frame rod state determination device of the second embodiment. FIG. 12 is a functional block diagram of the main part of the frame rod state determination device of the third embodiment. FIG. 13 is a flowchart corresponding to FIG. 8 in the frame rod state determination device of the third embodiment. FIG. 14 is a diagram showing the contents of an abnormality occurring in a frame rod and the contents of a change in data.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings. First, an overview of the present embodiment (first and second embodiments) will be described before the description of the embodiment.

[Outline of Embodiment 1]
When an abnormality occurs in the condition of the flame rod, a change occurs in the ignition delay time. For example, when the insulation deterioration of the flame rod, the rust of the flame rod, the wiring insulation failure of the flame rod, and the contact failure occur, the ignition delay time becomes long.

  In the first embodiment, the time from the start of fuel supply to the burner (fuel valve opening) (point t1 shown in FIG. 1A) to the point when it is determined that there is a flame (point t2 shown in FIG. 1B) Time, that is, the time until the flame detection signal (frame voltage VF) from the flame rod becomes VF VF VFmin is measured by the timer (Fig. 1 (c)), and the time measured by this timer is the ignition delay time Td.

  The measurement of the ignition delay time Td is repeated each time the combustion apparatus is started, and a data range that can be taken when there is no malfunction is derived as a normal range.

  Then, during operation of the combustion apparatus, the ignition delay time Td is measured, and when the measured ignition delay time Td is within the normal range but deviates from the normal range, the flame rod is in a malfunctioning state judge.

  For example, an average value of the ignition delay time Td repeatedly measured is set as a reference ignition delay time TdB (see FIG. 2), and a normal range is determined based on the reference ignition delay time TdB. When the measured ignition delay time Td is within the normal range (Td ≦ Tdmax) but deviates from the normal range (Td <TdH), that is, when TdH ≦ Td ≦ Tdmax, the flame rod Is determined to be in a bad state.

  Note that Tdmax is a boundary value for determining an abnormality, and is set to be longer than the upper limit boundary value TdH of the normal range. Further, the reference ignition delay time TdB may not be an average value of the measured ignition delay times Td, but may be determined as an initial value at the start of operation.

  Further, in this example, although the flame detection signal from the flame rod is acquired as the flame voltage VF, the flame current is acquired as the flame current IF, and the flame rod is in a state of malfunction similarly to the flame voltage VF. It may be determined whether or not.

  In addition, it may be determined that the ignition delay time Td is in a malfunction state by a single deviation from the normal range, or it may be determined that a malfunction is in a malfunction state by a certain number of deviations or more. It is also good. In addition, during operation of the combustion apparatus, if the number of times of deviation from the normal range occurs a certain percentage or more, it may be determined that the system is in a malfunctioning state or the like. In addition, the determination as to whether or not there is a malfunction may be made in real time or may be confirmed from the operation history.

[Outline of Embodiment 2]
When an abnormality occurs in the state of the frame rod, a change occurs in the frame voltage VF. For example, when the insulation deterioration of the flame rod, the rust of the flame rod, the wiring insulation failure of the flame rod, and the contact failure occur, the flame voltage VF decreases.

  In the second embodiment, it is determined whether or not the state of the flame rod is malfunctioning not only from the ignition delay time Td but also from the flame voltage VF during steady-state combustion. That is, when there is a departure from the normal range for both the ignition delay time Td and the frame voltage VF during steady-state combustion, it is determined that the possibility that the flame rod is malfunctioning is higher.

  As a measure for this, in the second embodiment, every time the combustion apparatus is operated, measurement of the frame voltage VF during steady-state combustion is repeated, and a data range that can be taken when there is no malfunction is derived as a normal range.

  Then, during operation of the combustion apparatus, the frame voltage VF during steady-state combustion is monitored, and when the frame voltage VF during the steady-state combustion falls within the normal range but deviates from the normal range, the flame rod malfunctions. It determines that it is in the state.

  For example, the average value of the frame voltage VF during steady combustion repeatedly measured is set as a reference frame voltage VFB (see FIG. 3), and a predetermined range centered on the reference frame voltage VFB is set as a normal range. Then, when the measured frame voltage VF during steady-state combustion is within the normal range (VFmin VF VF VF VFmax) but deviates from the normal range (VFL <VF <VFH), the frame rod is out of order. It is determined that

  Note that VFmin and VFmax are boundary values for determining abnormality, and VFmin is set as a value smaller than the lower limit side boundary value VFL of the normal range, and VFmax is higher than the upper limit side boundary value VFH of the normal range Is also set as a large value. Further, the reference frame voltage VFB may not be an average value of the measured frame voltages VF during steady-state combustion, but may be determined as an initial value at the start of operation.

  Further, in this example, although the flame detection signal from the flame rod is acquired as the flame voltage VF, the flame current is acquired as the flame current IF, and the flame rod is in a state of malfunction similarly to the flame voltage VF. It may be determined whether or not.

  Alternatively, it may be determined that the vehicle is in a malfunctioning state due to a short deviation from the normal range of the frame voltage VF during steady-state combustion, or the average value of the frame voltage VF during steady-state combustion over a fixed time is taken. If this average value deviates from the normal range, it may be determined that the system is in a malfunctioning state. In addition, it may be determined that the vehicle is in a malfunctioning state when the time out of the normal range is a constant rate or more during steady-state combustion. In addition, the determination as to whether or not there is a malfunction may be made in real time or may be confirmed from the operation history.

  In this example, VFmax is defined as the upper limit boundary value of the normal range, and VFH is defined as the upper limit boundary value of the normal range. However, VFmax and VFH are eliminated, that is, the range of VFmin or more All in the normal range, and if the frame voltage VF during steady-state combustion exceeds VFL, it is determined that the normal state is in effect, and if it is between VFmin and VFL, it is determined that the abnormal state is in effect. You may

Embodiment
FIG. 4 shows the main part of a combustion system including one embodiment of the flame rod state determination device according to the present invention. The combustion system 100 includes a combustion device 1, a combustion control device 2, a fuel flow path 3, and an air flow path 4.

  The combustion apparatus 1 includes a combustion chamber 5, a main burner 6 for heating the inside of the combustion chamber 5, a pilot burner 7 for igniting the main burner 6, and an ignition device (IG) 8 for igniting the pilot burner 7. A flame rod 9 for detecting the flame intensity of the burners (pilot burner 7 and main burner 6) and a temperature sensor 10 for detecting the temperature in the combustion chamber 5 are provided.

  The fuel flow path 3 is a flow path for supplying fuel to the combustion device 1 and includes a main flow path 3a to which fuel is supplied from the outside, and a first flow path 3b and a second flow branched from the main flow path 3a. It is comprised from the path 3c. The first flow path 3 b is connected to the main burner 6, and the second flow path 3 c is connected to the pilot burner 7. Further, a gas pressure switch 15 is provided in the main flow passage 3a, safety shut-off valves 11, 12 and a damper (fuel flow rate adjustment damper) 19 are provided in the first flow passage 3b, and a second flow passage 3c is provided. The safety shutoff valves 13 and 14 are provided.

  One end of the air flow path 4 is connected to the blower 16, and the other end is connected to the first flow path 3b. Air (air) discharged from the blower 16 is supplied to the main burner 6 together with fuel (gas) via the first flow path 3b. In the air flow path 4, a wind pressure switch (air flow switch) 17 and a damper (air flow rate adjustment damper) 18 are provided.

  In the air flow path 4, the air flow control damper 18 is driven by the control motor M in linkage with the fuel flow control damper 19. The control motor M has a high opening position sensor HS that detects that the opening position of the dampers 18 and 19 has reached a predetermined high opening position, and a low that detects that the opening position has reached a predetermined low opening position. An opening position sensor LS is provided.

  The combustion control device 2 includes a gas pressure signal from the gas pressure switch 15, an air pressure signal from the wind pressure switch 17, a flame detection signal from the flame rod 9 (a signal indicating the flame intensity of the burner), and a temperature from the temperature sensor 10. A detection signal or the like is input, and a control signal is output to the safety shutoff valves 11 to 14, the ignition device 8, the blower 16, the dampers 18, 19 and the like. As a result, the operation of the combustion device 20 shown by encircling the constituent elements in the figure by a dashed line is controlled.

  Depending on the type of the combustion apparatus 20, there is a type that extinguishes the flame of the pilot burner 7 when the main burner 6 is finished, a type that continues the flame of the pilot burner 7 even after the main burner 6 is ignited, In the former type, first, the flame intensity of the pilot burner 7 is detected, and then the flame intensity of the main burner 6 is detected. In the latter type, the flame strengths of the pilot burner 7 and the main burner 6 are detected together.

  In the present specification, both the pilot burner 7 and the main burner 6 are referred to as burners, and the flame detected by the flame rod 9 is referred to as the flame of the burner. FIG. 4 is of a type in which the flame of the pilot burner 7 is continued even after the ignition of the main burner 6, and the flame rod 9 detects the flames of the pilot burner 7 and the main burner 6 as flames of the burner.

  Further, in the combustion apparatus 20, the air flow path 4, the blower 16, and the air flow rate adjustment damper 18 constitute a supply system 101 of air to the combustion chamber 5, and the fuel flow path 3 (3a, 3b, 3c) The safety shutoff valves 11 to 14 and the fuel flow rate adjustment damper 19 constitute a fuel supply system 102 to the combustion chamber 5.

  There is also a type in which only the main burner is provided without providing a pilot burner, and in this type, as shown in FIG. 5, the inlet side and the outlet side of the main channel 3a are bypassed to A flow path 3c is provided, and a fuel flow rate adjustment damper 19 is provided between the burner 6 and a junction point on the outlet side of the main flow path 3a and the sub flow path 3c. In this case, the burner 6 doubles as a main burner and a pilot burner, and the pilot burner 7 becomes unnecessary.

  In the combustion system 100 (FIG. 4), an operation sequence from start of the combustion device 20 to steady combustion is defined as a combustion sequence. For example, as the operation sequence from the start of the combustion apparatus 20 to steady combustion, "start check", "pre-purge", "wait for ignition", "pilot ignition", "pilot only", "main ignition", "main stable" Each combustion sequence is defined as “stationary combustion”.

  FIG. 6 shows a time chart of the combustion sequence from startup of the combustion device 20 to steady state combustion. When the combustion control device 2 receives a start input (t1 point shown in FIG. 6 (a)), it sends a drive command to the control motor M in the opening direction (t1 point shown in FIG. 6 (d)) The air flow to the air flow path 4 is started (point t1 shown in FIG. 6 (b)). Thereby, the dampers 18 and 19 are opened, and the pressure in the air flow path 4 is increased.

  Then, when the pressure in the air flow passage 4 increases (the pressure of air to the combustion chamber 5 increases) and the pressure in the air flow passage 4 reaches a predetermined value, the wind pressure switch 17 is turned on (FIG. 6 (c T2 point shown in). A period P1 from the point t1 to the point t2 is a time zone of "start check".

  When the wind pressure switch 17 is turned on and the high opening position sensor HS detects that the opening positions of the dampers 18 and 19 have reached the high opening position (t3 shown in FIG. 6 (e)). Point) The timing of the pre-purge time S1 is started from this time point.

  The combustion control device 2 sends a drive command in the closing direction to the control motor M after the lapse of the pre-purge time S1 (at t4 point shown in FIG. 6 (d)). Thus, the openings of the dampers 18 and 19 are closed. A period P2 from the point t3 to the point t4 is a time zone of "prepurge".

  When the low opening position sensor LS detects that the opening position of the dampers 18 and 19 has reached the low opening position (t5 point shown in FIG. 6F), the combustion control device 2 performs the predetermined waiting time S2 After that, the safety shutoff valves (pilot valves) 13 and 14 are opened (t6 point shown in FIG. 6 (g)) and the igniter (ignition) 8 is operated (t6 point shown in FIG. 6 (h)) The pilot burner 7 is ignited (t6 point shown in FIG. 6 (i)). A period P3 from the point t4 to the point t6 is a time zone of "waiting for ignition".

  When the combustion control device 2 ignites the pilot burner 7, the safety shut-off valves (main valves) 11 and 12 are opened after the lapse of time S3 which is the sum of the pilot ignition time and the pilot only time (see FIG. Ignition to the main burner 6 is performed at time t8 shown in 6 (j) (time t8 shown in FIG. 6 (k)). In this case, the period during which the igniter 8 is operating, that is, the period P4 from t6 to t7 shown in FIG. 6 (h) is the "pilot ignition" time period, and the period P5 from t7 to t8. Is the "pilot only" time zone.

  When the combustion control device 2 ignites the main burner 6, the proportional control of the opening degree of the dampers 18 and 19 is started after a lapse of time S4 which is the sum of the main ignition time and the main stabilization time (see FIG. Transition to steady-state combustion at t10 point shown in 6 (d). Of the period from t8 to t10, period P6 from t8 to t9 is the "main ignition" time period, and period P7 from t9 to t10 is the "main stable" time period. There is a period P8 after the t10 point which is a time zone of "steady combustion".

  In the present embodiment, a flame rod state determination device 21 that determines the state of the frame rod 9 is provided in the combustion control device 2 that performs an operation according to such a combustion sequence. That is, as one of the functions of the combustion control device 2, a function of determining the state of the flame rod is provided. The flame rod state determination device 21 may be provided outside the combustion control device 2 instead of the combustion control device 2.

First Embodiment
In FIG. 7, the functional block diagram of the principal part of the state determination apparatus (frame rod state determination apparatus) of the flame | frame rod of Embodiment 1 is shown. The frame rod state determination device 21 is realized by hardware including a processor and a storage device, and a program that realizes various functions in cooperation with the hardware.

  The flame rod condition determination device 21 is a functional unit unique to the present embodiment, and includes a flame presence / absence determination unit 21-1, a timer 21-2, a first ignition delay determination unit 21-3, and a second ignition. A delay determination unit 21-4, a frame voltage determination reference level storage unit 21-5, a determination reference time storage unit 21-6, and a determination result output unit 21-7 are provided.

  In the frame rod state determination device 21, the frame voltage determination reference level storage unit 21-5 stores a reference level VFmin as a threshold for determining the presence or absence of a flame. In the judgment reference time storage unit 21-6, the first judgment reference time Tdmax taken as the upper limit boundary value of the normal range as the judgment reference time for the ignition delay time Td and the upper limit boundary of the normal range A second determination reference time TdH, which is a value, is stored. The second determination reference time TdH is derived as described above with reference to FIG.

  Hereinafter, the functions of the respective parts of the frame rod state determination device 21 will be described with reference to the flowchart shown in FIG.

  In the frame rod state determination device 21, the timer 21-2 starts the timing operation with the start of fuel supply to the burner (fuel valve open) as the starting point (YES in step S101) (step S102). In this example, the timing at which the pilot valves 13 and 14 are opened (point t6 shown in FIG. 6 (g)) is taken as the fuel supply start timing to the burner.

  The flame presence / absence determination unit 21-1 monitors the flame detection signal (frame voltage VF) from the flame rod 9 (step S103), and the frame voltage VF is stored in the frame voltage determination reference level storage unit 21-5. If the level Vmin has been reached (YES in step S104), it is determined that there is a flame, and the timer 21-2 stops the timing operation (step S105). The timer 21-2 sends the measured time T at this time as the ignition delay time Td to the first ignition delay determination unit 21-3 (step S106).

  The first ignition delay determination unit 21-3 compares the ignition delay time Td from the timer 21-2 with the second determination reference time TdH stored in the determination reference time storage unit 21-6 (step S107). And when Td <TdH (YES in step S107), it is determined that the frame rod 9 is in the normal state (step S109).

  If Td <TdH is not satisfied, that is, if Td ≧ TdH (NO in step S107), the first ignition delay determination unit 21-3 determines that the flame rod 9 is in a failure state (step S108). ).

  The timer 21-2 continues the clocking operation while the frame voltage VF is VF <VFmin (NO in step S104). The second ignition delay determination unit 21-4 monitors the counting time T of the timer 21-2 (step S110), and the counting time T of the timer 21-2 is stored in the determination reference time storage unit 21-6. When the first determination reference time Tdmax is exceeded (YES in step S111), it is determined that the frame rod 9 is in an abnormal state (step S112). Then, the time counting operation of the timer 21-2 is stopped (step S113).

  In the present embodiment, the ignition delay time Td sent from the timer 21-2 to the first ignition delay determination unit 21-3 does not exceed Tdmax. Therefore, it can be said that the ignition delay time Td when it is determined that the first ignition delay determination unit 21-3 is malfunctioning is TdH ≦ Td ≦ Tdmax.

  The determination results obtained by the first ignition delay determination unit 21-3 and the second ignition delay determination unit 21-4 are sent to the determination result output unit 21-7. The determination result output unit 21-7 sends the determination results from the first ignition delay determination unit 21-3 and the second ignition delay determination unit 21-4 to the monitoring device 30, and the screen of the monitoring device 30 (monitoring screen) Display on 30-1.

  The monitoring device 30 may be in the combustion control device 2 or may be provided outside the combustion control device 2. Moreover, the monitoring apparatus 30 may be provided in the remote place via the internet.

[Modification of Embodiment 1]
In this frame rod state determination device 21, VFmin is set to the first reference level (boundary value on the lower limit side of the normal range of the frame voltage VF), and the second reference level VFmax is set to the upper limit side of the normal range of the frame voltage VF. The frame rod 9 may be determined to be in an abnormal state when the frame voltage VF exceeds VFmax.

  FIG. 9 shows a configuration example (a modified example of the first embodiment) of the frame rod state determination device 21 when it is determined that the frame rod 9 is in an abnormal state when the frame voltage VF exceeds VFmax. Show. Hereinafter, the frame rod state determination device 21 shown in FIG. 7 will be referred to as 21A, and the frame rod state determination device 21 shown in FIG. 9 will be referred to as 21B.

  In the frame rod state determination device 21B shown in FIG. 9, the first reference level VFmin and the second reference level VFmax are stored in the frame voltage determination reference level storage unit 21-5. Then, a flame level determination unit 21-8 is provided, and when the frame voltage VF exceeds the second reference level VFmax, it is determined that the frame rod 9 is in an abnormal state, and the determination result is output as a determination result output unit 21. It is sent to -7.

[Comparison of state determination logic]
FIG. 10 shows the logic of state determination in the flame rod state determination devices 21A and 21B in comparison with the prior art. 10 (a) shows the logic of the state determination of the prior art, FIG. 10 (b) shows the logic of the state determination in the frame rod state determination device 21A, and FIG. 10 (c) shows the logic of the state determination in the frame rod state determination device 21B. Indicates

  In the prior art (FIG. 10A), reference level VFmin, which is the lower limit boundary value of the normal range with respect to frame voltage VF, and determination reference time Tdmax, which is the upper limit boundary value of normal range with respect to ignition delay time Td If the frame voltage VF reaches VFmin before the measured time T exceeds the determination reference time Tdmax (T ≦ Tdmax) (VF ≧ VFmin), it is determined as “normal”, and the measured time T is determined as a determination standard When the time Tdmax is exceeded (T> Tdmax), it is determined as "abnormal". When the frame voltage VF is VF <VFmin, the determination of "normal" / "abnormal" is not performed until the measured time T exceeds the determination reference time Tdmax.

  On the other hand, in the flame rod state determination device 21A, as shown in FIG. 10B, the determination reference time Tdmax (boundary value on the upper limit side of the normal range with respect to the ignition delay time Td) is taken as the first determination reference time. A second determination reference time TdH (boundary value on the upper limit side of the normal range with respect to the ignition delay time Td) is provided before the first determination reference time Tdmax, and the measured time T is between TdH and Tdmax. If the frame voltage VF reaches VFmin (VF VF VFmin) in some cases (TdH T T T Tdmax), it is determined as "malfunction" and before time-counting time T reaches the second determination reference time TdH (T < When the frame voltage VF reaches VFmin at TdH (VFVFVFmin), it is determined as “normal”.

  That is, in the frame rod state determination device 21A, the region determined as "normal" in the determination logic of the prior art (FIG. 10 (a)) is "normal" and "out of order" in the direction of the horizontal axis showing the timekeeping time T. It divides into "judgment area".

  In the frame rod state determination device 21B, as shown in FIG. 10C, the reference level VFmin (boundary value on the lower limit side of the normal range with respect to the frame voltage VF) is set as a first reference level. A second reference level VFmax (boundary value on the upper limit side of the normal range with respect to the frame voltage VF) is provided at a position higher than VFmin, and "abnormal" when the frame voltage VF exceeds VFmax (VF> VFmax) judge.

  That is, in the frame rod state determination device 21B, in the determination logic (FIG. 10 (b)) of the frame rod state determination device 21A, in the direction of the vertical axis indicating the frame voltage VF, It divides into the determination area | region of "normal" and "abnormality", and supposes that the area | region determined as "malfunction" is divided into the determination area | region of "malfunction" and "abnormality."

Second Embodiment
In FIG. 11, the functional block diagram of the principal part of the flame | frame rod state determination apparatus of Embodiment 2 is shown. This flame rod condition determination device 21 (21C) is based on the flame rod condition determination device 21A (FIG. 7) of the first embodiment, and the flame level determination unit 21- during combustion is further added to the configuration of the flame rod condition determination device 21A. 9 is provided.

  Further, in the frame rod state determination device 21C, the first reference level VFmin (boundary value on the lower limit side of the normal range with respect to the frame voltage VF) and the second reference are stored in the frame voltage determination reference level storage unit 21-5. Level VFmax (boundary value on the upper limit side of the normal range for the frame voltage VF), third reference level VFL (boundary value on the lower limit side of the normal range for the frame voltage VF), fourth reference level VFH (frame The upper limit boundary value of the normal range with respect to the voltage VF is stored. The third reference level VFL and the fourth reference level VFH are derived as described above with reference to FIG.

  In the flame rod state judging device 21C, the in-combustion flame level judging unit 21-9 monitors the flame voltage VF in the steady combustion, and the flame voltage VF in the steady combustion is the first reference level VFmin and the third reference The frame rod 9 is out of order when it is between the level VFL (VFmin VF VF V VFL) or when it is between the second reference level VFmax and the fourth reference level VFH (VFH VF VF VF VFmax) If the frame voltage VF during steady-state combustion falls below the first reference level VFmin (VF <VFmin) or exceeds the second reference level VFmax (VF> VFmax), the flame rod 9 The frame voltage VF during steady-state combustion is determined to be in the abnormal state, and the third reference level VL and the fourth reference level VH are determined. If there between is determined that (VL <VF <VH) a flame rod 9 is in a normal state.

Third Embodiment
FIG. 12 shows a functional block diagram of the main part of the frame rod state determination device of the third embodiment. This frame rod state determination device 21 (21D) is based on the frame rod state determination device 21A (FIG. 7) of the first embodiment, and the configuration of the frame rod state determination device 21A further includes an ignition delay time storage unit 21-10. And a third ignition delay determination unit 21-11.

Every time the ignition delay time Td is counted by the timer 21-2, the ignition delay time storage unit 21-10 stores the ignition delay time Td in time series. The third ignition delay determination unit 21-11 counts the ignition delay time Tdn counted this time and the ignition delay time Tdn- ₁ counted last time every time the ignition delay time Td is counted by the timer 21-2. If it is determined that the reverse relationship is occurring in the long and short relationship, it is determined that the frame rod 9 is in an abnormal state, and the determination result is output as the determination result output unit 21- Send to 7

For example, in the case where an abnormality such as a spark jumping into the flame rod 9 occurs, the ignition delay time Td becomes long or short. In the flame rod state determination device 21D of the third embodiment, by comparing the ignition delay time Tdn counted this time and the ignition delay time Tdn- ₁ counted last time, the long and short relationship is determined by comparing it with the past. An abnormality such as a spark jumping into the frame rod 9 is also detected. FIG. 14 shows the contents of the abnormality occurring in the frame rod 9 and the contents of the change of the data.

In this embodiment, although the ignition delay time Tdn counted this time and the ignition delay time Tdn- ₁ counted last time are compared retrospectively in the past, for example, they are stored in the ignition delay time storage unit 21-10. With regard to the ignition delay time Td of the predetermined period up to the present, the ignition delay time Td before and after adjacent to each other is compared with the ignition delay time Tdn counted this time and the ignition delay time Tdn- ₁ counted last time . Then, a threshold value is set with respect to the number of times of occurrence of the reversal, and it is determined whether the reversal is occurring in the long and short relationship.

  FIG. 13 shows a flowchart corresponding to FIG. 8 in this frame rod state determination device 21D. In the figure, the processing of steps S201 to S206 corresponds to the processing of steps S101 to S106 in FIG. 7, the processing of steps S210 to S216 corresponds to the processing of steps S107 to S113 in FIG.

In the frame rod state determination device 21D, in step S207, the ignition delay time storage unit 21-10 stores the present ignition delay time Td as Tdn. Then, in step S208, the ignition delay time Tdn counted this time and the ignition delay time Tdn- ₁ counted last time are compared retrospectively in the past to determine the long / short relationship. Here, when it is determined that the reverse rotation is occurring in the long / short relationship (YES in step S209), it is determined that the frame rod 9 is in an abnormal state (step S215).

  In this manner, in the present embodiment (first, second, and third embodiments), it is possible to early know that the normal state of the flame rod 9 is in a normal but malfunctioning state before the state of the frame rod 9 becomes abnormal. Will be able to That is, it is possible to detect in advance the abnormality of the insulation rod of the frame rod 9 such as insulation deterioration and to notify the administrator of the necessity of maintenance at an early stage before becoming the abnormal state. This eliminates the need for frequent maintenance and avoids cost increases.

  In addition, although it takes time and effort to restore the combustion apparatus 20 in the lockout state, this can be prevented before the lockout state is achieved, that is, abnormality in the state of the flame rod 9 can be efficiently pre-paid. By detecting and removing it, the burden on the administrator can be reduced.

  Further, in the second embodiment, the determination results of “normal” / “abnormal” / “fault” of the flame rod 9 can be obtained for both the ignition delay time Td and the frame voltage VF during steady combustion. Here, when not only the ignition delay time Td but also the frame voltage VF is determined to be “a malfunction,” it can be determined that the possibility that the flame rod 9 is malfunctioning is higher. Thereby, the reliability of the malfunction determination can be enhanced.

  Also, as described in the "Summary of the embodiment", in the first to third embodiments described above, the flame detection signal from the flame rod 9 is acquired as the flame current IF, similarly to the flame voltage VF, It may be made to judge "normal" / "abnormal" / "fault" of the frame rod 9.

  In the first to third embodiments, the ignition delay time Td is measured with the timing at which the pilot valves 13 and 14 are opened as the fuel supply start timing to the burner, but the main valves 11 and 12 are opened. The ignition delay time Td may be measured as the timing at which the supply of fuel to the burner is started. In addition, the ignition delay time Td from the start of combustion may be measured by using the start of ignition to the ignition device 8 as the timing of start of combustion to the burner instead of the start of supply of fuel to the burner.

[Others]
If a phenomenon occurs where ignition detection is not properly performed and the combustion device is locked out, if changes in the ignition delay time and the flame voltage are confirmed, the cause of the abnormality in the flame rod may be investigated. Also available.

  In addition, it is possible to grasp the problem of the combustion state by observing the change over time of the ignition delay time and the frame voltage. For example, when an increase in the ignition delay time and a decrease in the flame voltage at the time of combustion gradually progress, it can be determined that an abnormality such as rust or insulation deterioration of the flame rod is gradually progressing. In that case, it can be determined that there is a high possibility that there is a problem in the installation environment of the flame rod. Using this, it is possible to detect an abnormality of the frame rod and prevent the reoccurrence by optimizing the installation environment.

[Extension of the embodiment]
Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the technical idea of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... combustion apparatus, 2 ... combustion control apparatus, 6 ... main burner, 7 ... pilot burner, 8 ... igniter (ignition), 11, 12 ... safety cutoff valve (main valve), 13, 14 ... safety cutoff valve (pilot Valves, 21 (21A, 21B, 21C, 21D) ... flame rod state determination device, 21-1 ... flame presence / absence determination unit, 21-2 ... timer, 21-3 ... first ignition delay determination unit, 21-4 ... 2nd ignition delay judgment unit, 21-5 ... frame voltage judgment reference level storage unit, 21-6 ... judgment reference time storage unit, 21-7 ... judgment result output unit, 21-8 ... flame level judgment unit, 21 -9 ... flame level determination unit during combustion, 21-10 ... ignition delay time storage unit, 21-11 ... third ignition delay determination unit, 100 ... combustion system.

Claims (7)

Determine the state of the flame rod in a combustion system comprising an ignition device for igniting a burner, and a flame rod for detecting the flame intensity of the burner by the current flowing to an electrode rod inserted in the flame A frame rod state determination device,
A flame presence / absence determination unit configured to determine that the flame is present when the flame intensity detected by the flame rod reaches a predetermined first reference level;
A timer configured to measure, as an ignition delay time, a time from the start of combustion to the burner to the determination as to presence of flame by the flame presence / absence determination unit;
It is configured to determine that the flame rod is in a malfunctioning state when the ignition delay time measured by the timer is within a predetermined normal range but deviates from the normal range. An apparatus for determining a condition of a flame rod, comprising: an ignition delay determining unit according to claim 1; In the frame rod state determination device described in claim 1,
Judgment reference time storage for storing a first judgment reference time determined as a boundary value on the upper limit side of the normal range and a second judgment reference time determined as a boundary value on the upper limit side of the normal range Equipped with
The first ignition delay determination unit
It is determined that the flame rod is in a malfunctioning state when the ignition delay time counted by the timer is between the first determination reference time and the second determination reference time. State determination device of. In the frame rod state determination device according to claim 2,
The first ignition delay determination unit
When the ignition delay time counted by the timer is between the first determination reference time and the second determination reference time, it is determined that the flame rod is in a malfunctioning state;
It is determined that the frame rod is in the normal state when the ignition delay time measured by the timer is less than the second determination reference time. In the flame rod state determination device according to claim 2 or 3,
A second ignition delay judging unit configured to monitor the clocked time of the timer and to judge that the frame rod is in an abnormal state when the clocked time exceeds the first judgment reference time; A frame rod state determination device characterized by comprising. In the frame rod state determination device according to any one of claims 1 to 4,
The first reference level is the lower limit boundary value of the normal range of the flame strength, and the second reference level higher than the first reference level is the upper limit of the normal range of the flame strength A determination reference level storage unit which stores the value as a boundary value of
And a flame level determination unit configured to determine that the flame rod is in an abnormal state when the flame intensity detected by the flame rod exceeds the second reference level. Frame rod state determination device. In the frame rod state determination device according to any one of claims 1 to 4,
The first reference level is the lower limit boundary value of the normal range of the flame strength, and the second reference level higher than the first reference level is the upper limit of the normal range of the flame strength A third reference level, which is higher than the first reference level and lower than the second reference level, is used as the lower limit value of the lower limit of the normal range of the flame intensity. A criterion level storage unit which stores a fourth reference level lower than the reference level and higher than the third reference level as the upper limit boundary value of the normal range;
Monitoring the flame intensity during steady-state combustion of the burner detected by the flame rod, where the intensity of the flame during steady-state combustion is between the first reference level and the third reference level Alternatively, it is determined that the flame rod is in a malfunctioning state when it is between the second reference level and the fourth reference level, and the intensity of the flame during the steady combustion is the first reference level. If the flame rod is in an abnormal state if the flame rod falls below or exceeds the second reference level, the intensity of the flame during the steady-state combustion is the third reference level and the fourth reference level. And a flame-under-combustion level determination unit configured to determine that the flame rod is in a normal state when it is between the reference level and the reference level. In the frame rod state determination device according to any one of claims 1 to 6,
Every time the ignition delay time is measured by the timer, the measured ignition delay time and the previously measured ignition delay time are compared retrospectively in the past to determine the long / short relationship, and the reverse occurs in the long / short relationship. And a third ignition delay determination unit configured to determine that the frame rod is in an abnormal state when it is determined that the frame rod is in the abnormal state.

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