JP2019074290A - State determination device of uv sensor - Google Patents

Abstract

To early detect an abnormal state of a UV sensor, such as dirt.SOLUTION: A state detection device of a UV sensor 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 UV sensor is in a failure state.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a state determination device of a UV sensor (ultraviolet sensor) that detects the intensity of a flame by receiving ultraviolet rays generated as the flame occurs.

  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 UV sensor, and a flame detection signal (a signal indicating the flame intensity of the burner) from the UV sensor is acquired as, for example, a flame voltage VF. 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 the UV sensor is contaminated, the flame detection is not properly performed, and it is not determined that the flame is present although the flame is generated, 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 that the UV sensor is dirty at an early stage, it can be dealt with before the combustion device is locked out, but for that purpose a skilled technician can You need to check the status regularly. In this case, it is not clear whether the UV sensor is contaminated or not. For this reason, it is necessary to perform maintenance regularly also for things that are not actually dirty and do not require maintenance, which leads to an increase in cost.

  The present invention has been made to solve such problems, and the object of the present invention is to provide a UV sensor state determination device capable of early detecting an abnormality such as a contamination of a UV sensor. It is 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 UV sensor state determination device (21) for determining the state of a UV sensor in a combustion system (100) having a UV sensor (9) for detecting, wherein the flame intensity detected by the UV sensor 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 the ignition delay time measured by the timer is within a normal range that is predetermined but is usually If deviated from the range, characterized in that it comprises first ignition delay determination unit which UV sensor is configured to determine to be in disordered state and (21-3).

  In the present invention, the flame determination unit determines that the flame is present when the intensity of the flame detected by the UV sensor 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 UV sensor is in a malfunctioning state when the ignition delay time counted 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 UV sensor is in a malfunctioning state.

  In the present invention, for example, when the UV sensor is contaminated and the degree of the contamination 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 UV sensor is in a malfunctioning state. This makes it possible to detect the contamination of the UV sensor early.

  In the present invention, the flame strength detected by the UV sensor 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, if the ignition delay time measured by the timer is within the normal range but deviates from the normal range, it is determined that the UV sensor is in a malfunctioning state As a result, it becomes possible to detect an abnormality such as a contamination of the UV sensor at an early stage.

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 UV sensor state determination apparatus 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 state determination device of the UV sensor according to the first embodiment. FIG. 8 is a flowchart for explaining the function of each part of the UV sensor state determination device of the first embodiment. FIG. 9 is a functional block diagram showing a modification of the UV sensor 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 UV sensor state determination device of the second embodiment.

  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]
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 UV sensor becomes VF VF VFmin (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 UV sensor 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 UV sensor 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.

  Also, in this example, although the flame detection signal from the UV sensor is acquired as the frame voltage VF, the flame current signal is acquired as the frame current IF, and the UV sensor is in a state of malfunction similarly to the frame 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]
In the second embodiment, it is determined whether or not the state of the UV sensor is malfunctioning not only from the ignition delay time Td but also from the frame voltage VF during steady-state combustion. That is, when there is a deviation 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 UV sensor 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 flame voltage VF during steady combustion is monitored, and when the flame voltage VF during steady combustion falls within the normal range but deviates from the normal range, the UV sensor 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. And, 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 UV sensor 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.

  Also, in this example, although the flame detection signal from the UV sensor is acquired as the frame voltage VF, the flame current signal is acquired as the frame current IF, and the UV sensor is in a state of malfunction similarly to the frame 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 UV sensor 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 UV sensor (ultraviolet sensor) 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 UV sensor 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 ignition of the main burner 6 is finished, and a type that continues the flame of the pilot burner 7 even after the ignition of the main burner 6 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 UV sensor 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 UV sensor 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 UV sensor state determination device 21 that determines the state of the UV sensor 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 UV sensor is provided. The state determination device 21 of the UV sensor 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 (UV sensor state determination apparatus) of UV sensor of Embodiment 1 is shown. The UV sensor 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 UV sensor state determination device 21 has a flame presence / absence determination unit 21-1, a timer 21-2, a first ignition delay determination unit 21-3, and a second ignition as functional units unique to the present embodiment. 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 UV sensor 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 units of the UV sensor state determination device 21 will be described with reference to the flowchart shown in FIG.

  In the UV sensor state determination device 21, the timer 21-2 starts the clocking operation with the start of fuel supply to the burner (fuel valve opening) 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 UV sensor 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). If Td <TdH (YES in step S107), it is determined that the UV sensor 9 is in the normal state (step S109).

  If Td <TdH, that is, if Td ≧ TdH (NO in step S107), the first ignition delay determination unit 21-3 determines that the UV sensor 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 UV sensor 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 the UV sensor state determination device 21 according to the first embodiment, VFmin is set to a first reference level (boundary value on the lower limit side of a normal range of the frame voltage VF), and a second reference level VFmax is set to a normal of the frame voltage VF. The boundary value on the upper limit side of the range may be determined, and when the frame voltage VF exceeds VFmax, it may be determined that the UV sensor 9 is in an abnormal state.

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

  In the UV sensor state determination device 21B illustrated in FIG. 9, the frame voltage determination reference level storage unit 21-5 stores the first reference level VFmin and the second reference level VFmax. 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 UV sensor 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 UV sensor state determination devices 21A and 21B in comparison with the prior art. 10A shows the logic of the state determination of the prior art, FIG. 10B shows the logic of the state determination in the UV sensor state determination device 21A, and FIG. 10C shows the logic of the state determination in the UV sensor 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 UV sensor 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 UV sensor state determination device 21A, the region determined as "normal" in the determination logic of the prior art (FIG. 10 (a)) is "normal" and "unhealthy" in the direction of the horizontal axis indicating the clock time T. It divides into "judgment area".

  In the UV sensor state determination device 21B, as shown in FIG. 10 (c), 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 UV sensor state determination device 21B, in the determination logic (FIG. 10B) of the UV sensor state determination device 21A, in the direction of the vertical axis indicating the frame voltage VF, the region determined as "normal" 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
FIG. 11 shows a functional block diagram of the main part of the UV sensor state determination device of the second embodiment. The UV sensor state determination device 21 (21C) is based on the UV sensor state 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 UV sensor state determination device 21A. 9 is provided.

  Further, in the UV sensor state determination device 21C, the frame voltage determination reference level storage unit 21-5 includes the first reference level VFmin (the lower limit of the normal range for the frame voltage VF) and the second reference. 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 UV sensor state determination device 21C, the during-combustion flame level determination unit 21-9 monitors the flame voltage VF during steady-state combustion, and the flame voltage VF during steady-state combustion is the first reference level VFmin and the third reference The UV sensor 9 has a malfunction 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) The UV sensor 9 determines that the flame voltage during steady-state combustion falls below the first reference level VFmin (VF <VFmin) or exceeds the second reference level VFmax (VF> VFmax). It is determined that the frame voltage VF during steady combustion is between the third reference level VL and the fourth reference level VH when it is determined that the abnormal state is present. The (VL <VF <VH) determines that the UV sensor 9 is in a normal state.

  In this manner, in the present embodiment (Embodiments 1 and 2), it is possible to early know that it is in a normal but malfunctioning state before the state of the UV sensor 9 becomes abnormal. It will be. That is, it is possible to detect in advance the abnormality of the UV sensor 9 such as dirt, and to notify the administrator of the necessity of maintenance at an early stage before becoming an 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, that is, contamination of the UV sensor 9 is efficiently detected in advance. By doing this, it is possible to reduce the burden on the administrator. In addition, it is possible to prevent economic loss due to being locked out.

  Further, in the second embodiment, the determination result of “normal” / “abnormal” / “fault” of the UV sensor 9 can be obtained for both the ignition delay time Td and the frame voltage VF during steady-state 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 of the UV sensor 9 having a malfunction is higher. Thereby, the reliability of the malfunction determination can be enhanced.

  Also, as described in the "Summary of the embodiment", in the first and second embodiments, the flame detection signal from the UV sensor 9 is acquired as the frame current IF, and in the same manner as the frame voltage VF, the UV sensor The judgment of "normal" / "abnormal" / "fault" may be performed.

  In the first and second 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 open. 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 the ignition detection is not properly performed and the combustion device is locked out, if changes in the ignition delay time and the frame voltage are confirmed, it is also used to investigate the cause of whether the UV sensor is affected or not. it can.

  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 the increase in the ignition delay time and the decrease in the flame voltage at the time of combustion are gradually advancing, it can be judged that the contamination of the UV sensor is gradually advancing.

  In that case, it can be inferred that the UV sensor is being contaminated because there is a lot of wrinkles at the time of combustion. Inadequate air ratio may be the cause of the increase in pressure. From this, it is possible to detect contamination of the UV sensor and prevent the occurrence of contamination again by optimizing the air ratio.

[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 Valve), 21 (21A, 21B, 21C) ... UV sensor state determination device, 21-1 ... flame presence determination unit, 21-2 ... timer, 21-3 ... first ignition delay determination unit, 21-4 ... first Ignition delay determination unit 2; 21-5: frame voltage determination reference level storage unit; 21-6 ... determination reference time storage unit; 21-7 ... determination result output unit; 21-8 ... flame level determination unit; 21-9 ... flame level determination unit during combustion, 100 ... combustion system.

Claims (6)

UV for determining the state of the UV sensor in a combustion system comprising an ignition device for igniting a burner, and a UV sensor for detecting the intensity of the flame of the burner upon generation of the flame A sensor state determination device,
A flame presence / absence determination unit configured to determine that there is a flame when the intensity of the flame detected by the UV sensor 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;
The UV sensor is configured to determine that the UV sensor is in a malfunctioning state if the ignition delay time counted by the timer is within a predetermined normal range but deviates from the normal range. 1. A state determination device for a UV sensor, comprising: an ignition delay determination unit 1; In the UV sensor state determination device according to 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
A UV sensor characterized in that the UV sensor is in a malfunctioning state when an ignition delay time counted by the timer is between the first judgment reference time and the second judgment reference time. State determination device of. In the UV sensor state determination apparatus 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 UV sensor is in a malfunctioning state,
It is determined that the UV sensor is in the normal state when the ignition delay time counted by the timer is less than the second determination reference time. In the UV sensor status determination device according to claim 2 or 3,
A second ignition delay judging unit configured to monitor the clocking time of the timer and to judge that the UV sensor is in an abnormal state if the clocking time exceeds the first judgment reference time; A UV sensor state determination device characterized by comprising. In the UV sensor 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 UV sensor is in an abnormal state when the flame intensity detected by the UV sensor exceeds the second reference level. UV sensor status determination device. In the UV sensor 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;
The intensity of the flame during steady-state combustion of the burner detected by the UV sensor is monitored, and 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 UV sensor 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 steady-state combustion is the first reference level. The UV sensor is determined to be in an abnormal state when it falls below or exceeds the second reference level, and the intensity of the flame during the steady-state combustion is the third reference level and the fourth reference level. And a flame level determination unit configured to determine that the UV sensor is in the normal state when it is between the reference level and the UV level detection unit.

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