JP5845109B2 - Flame monitoring device - Google Patents

Description

The present invention relates to a flame monitoring device that detects and alerts to ultraviolet rays emitted from a flame.

  2. Description of the Related Art Conventionally, there is known a flame monitoring device that detects ultraviolet rays emitted from a flame and gives an alarm, and is used as an arson sensor or a flame detector.

  Such a flame monitoring apparatus uses an ultraviolet detection tube as a flame detection unit. The UV detector tube has an anode and a cathode placed in a glass tube that transmits UV light and encloses a special gas, and is emitted from a flame with a predetermined high voltage applied between the anode and the cathode. When ultraviolet light having a wavelength range of 185 to 260 nanometers is incident, an avalanche discharge is caused by the emission of photoelectrons. The amount of ultraviolet rays is detected by electrically taking out and counting the discharge of this ultraviolet ray detection tube as an ultraviolet ray detection pulse signal, and when the detected ultraviolet ray amount exceeds a predetermined threshold, flame is determined, and a flame determination signal is alarmed. Alarms are sent to devices and receivers. As such an ultraviolet detection tube, for example, a commercially available product as UV TRON (R) can be used.

The flame monitoring device adjusts the detection sensitivity according to the flame to be monitored. For example, when used as an arson sensor, in order to determine and warn a minute flame such as a writer, the detection threshold is set high by lowering the threshold for flame determination. In addition, when installed in a building and used as a flame detector, the flame detection threshold is raised and the detection sensitivity is set low to prevent false alarms by judging the writer's flame accompanying smoking. .

JP-A-6-325269 JP-A-3-174699 JP-A-6-290375 JP 2009-119165 A

  By the way, the ultraviolet ray detection tube provided in the flame monitoring device causes self-discharge in a state where a high voltage is applied even if ultraviolet rays are not incident due to manufacturing variations or the like, which causes a false alarm.

  In addition, when a flame monitoring device is installed and the period of use becomes longer, the number of self-discharges tends to increase due to deterioration of the ultraviolet detection tube, which also contributes to false alarms.

  In addition, the ultraviolet detector tube causes discharge due to factors in the natural world other than ultraviolet rays generated from the flame. These factors include sunlight, welding light, plasma, radiation, and cosmic rays. Although sunlight is generally considered not to cause discharge, it may cause discharge when it receives light due to reflection or the like. Cosmic rays come from outer space and pass through the UV detector tube at a certain frequency, causing discharge. The discharge of the UV detector tube due to such natural factors is unavoidable as background noise, and is a cause of false alarms.

  The false alarm of the flame monitoring device is prevented by accumulating the flame judgment result. When accumulation is included in the flame determination result, the flame determination is finalized when the flame determination result is continuously obtained a predetermined number of times.

  However, when using a flame monitoring device as an arson sensor, it is necessary to quickly capture a small flame when the arsonist ignites the writer trying to ignite, and at that time the accumulation time is increased in the judgment result. When set, it is impossible to reliably detect ultraviolet rays that are incident only for a short time. For this reason, the flame monitoring device used as an arson sensor cannot be sufficiently accumulated, and there remains a problem that false reports are likely to occur due to self-discharge or background noise.

  In addition, the flame monitoring device may generate an alarm due to various factors such as self-discharge of the UV detector tube, an increase in the number of self-discharges due to deterioration, and discharge due to factors existing in the natural world. Even if it is output, even if it goes to the installation site and investigates, there is a problem that the true cause cannot be pursued, so that an appropriate response cannot be taken and the reliability of the flame monitoring device may be impaired.

  In order to solve this problem, there is a flame monitoring device provided with a self-diagnosis unit (Patent Document 2). The self-diagnosis unit determines whether or not it is functioning normally by detecting the self-discharge of the ultraviolet ray detector tube that is performed at intervals of several minutes (there is actually variation and cannot be specified). That is, the number of self-discharges is input at regular time intervals. If the number of self-discharges exceeds a certain number, the ultraviolet detection tube is determined to be normal, and if the number is less than the predetermined number, the ultraviolet detection tube is determined to be abnormal.

  However, there is a problem in that even if the abnormality of the ultraviolet detection tube can be determined by self-diagnosis, it is not possible to directly determine the discharge stop failure. Even if the number of discharges is less than a certain number and the abnormality of the UV detection tube is judged, if there is even one self-discharge, there is a possibility that the flame can be correctly judged by discharging when the ultraviolet rays from the flame are incident. However, it is not necessarily an abnormality, and it can be said that the accuracy of abnormality determination is low in that a discharge stop failure cannot be directly determined.

  In addition, if the UV detector tube deteriorates due to aging, the number of self-discharges increases and it becomes easy to generate false alarms. However, it is not known that the cause of the false alarm is deterioration of the UV detector tube, and it is not possible to respond appropriately. Is left.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a flame monitoring apparatus that can reliably determine a flame to be monitored, and that is also suitable for arson monitoring for monitoring a particularly short and short flame.

It is another object of the present invention to provide a flame monitoring device that can appropriately cope with a failure by determining a failure such as a discharge stop failure or deterioration of an ultraviolet detection tube.

The present invention provides a flame monitoring apparatus,
A synchronization pulse signal having a period (T2) as a quotient (T1 / Nth) obtained by dividing a predetermined flame continuation time (T1) in which ultraviolet rays from a flame to be monitored continuously enter by a predetermined flame determination threshold (Nth) An oscillation unit that generates
An ultraviolet ray detection unit that includes an ultraviolet ray detection tube, outputs an ultraviolet ray detection pulse signal by a discharge operation of the ultraviolet ray detection tube when ultraviolet rays are incident from the outside in a voltage application state based on a signal of the oscillation unit;
A flame determination unit that determines a flame and outputs a flame determination signal when the number of continuous outputs (N) of the ultraviolet detection pulse signal matches a predetermined flame determination threshold value (Nth);
A failure determination unit that counts the ultraviolet detection pulse signal over a predetermined failure determination time, determines a failure of the ultraviolet detection unit based on the count value, and outputs a failure determination signal;
Is provided.

Further, the flame monitoring device of the present invention can change the detection sensitivity or the monitoring distance by changing the flame determination threshold while fixing the synchronization pulse signal generated in the oscillating unit at a predetermined period.

  The failure determination unit determines and outputs a discharge stop failure of the ultraviolet ray detection tube when the count value is zero.

Fault determining unit, the count value is, in the case of more than a predetermined fault determination threshold set in the range of less than the maximum count value when continuously large and UV detection pulse signal over a failure determination time output than zero, UV detection Outputs after judging the deterioration of the tube.

The failure determination unit determines and outputs the degree of deterioration of the ultraviolet detection tube by setting the failure determination threshold value in a plurality of stages and comparing the failure determination threshold with the count value.

  According to the present invention, the number of output of the ultraviolet detection pulse signal output by the discharge operation when the ultraviolet detection tube is applied with a voltage synchronized with the synchronization pulse signal every predetermined period (T2) and ultraviolet rays are incident from the outside. When (N) matches a predetermined flame determination threshold value (Nth), the flame is determined and the flame determination signal is output, so that accumulation of the flame determination signal (flame determination result) is not required, It is possible to reliably determine and warn a flame having a predetermined flame duration to be monitored.

  Also, self-discharge due to the characteristics and deterioration of the UV detector tube, or noise discharge due to background noise due to natural factors, is a single occurrence and should not be a continuous discharge as when UV light from a flame is incident. In many cases, the number of outputs of the ultraviolet detection pulse signal due to self-discharge or noise discharge does not reach the flame determination threshold (Nth), so that erroneous determination of flame can be reliably prevented.

  The period (T2) of the synchronization pulse signal generated in the oscillation unit is a period obtained by dividing a predetermined flame continuation time (T1) in which ultraviolet rays from the flame to be monitored continuously enter by the flame determination threshold (Nth). By setting (T1 / Nth), it is possible to reliably determine the flame by setting an appropriate detection sensitivity corresponding to the size of the flame to be monitored (flame duration).

  For example, in the case of arson monitoring, the flame due to the ignition of the writer has a flame duration of about 500 milliseconds, and when the flame determination threshold Nth for the number of continuous outputs of the ultraviolet detection pulse signal is set to Nth = 4, for example, the period of the synchronization pulse signal T2 becomes T2 = 500/4 = 125 milliseconds, and the flame to be monitored is determined by determining the flame from four consecutive discharge operations of the ultraviolet ray detector tube by the ultraviolet ray incident from the flame having a flame duration of 500 milliseconds. Flame determination can be performed with appropriate detection sensitivity corresponding to the duration.

  In this case, if the flame determination threshold Nth is changed to Nth = 5, for example, while maintaining the flame monitoring distance, the detection sensitivity is set to a flame having a flame duration of 625 milliseconds. If the flame determination value is changed to Nth = 3, the detection sensitivity is set to a flame having a flame duration of 375 milliseconds. Thus, the detection sensitivity corresponding to the flame duration of the flame to be monitored can be easily set.

  Further, the number of discharges is obtained by counting the ultraviolet detection pulse signal over a predetermined failure determination time, for example, 5 minutes, and the failure of the ultraviolet detection tube is determined based on the number of discharges, and a failure determination signal is output to give an alarm. Because of this, the discharge stop failure (failure of the UV detector tube, oscillation circuit or high voltage generation circuit) where the number of discharges becomes zero and the discharge of the UV detector tube stops, and the deterioration of the UV detector tube where the number of self-discharges increases Thus, it is possible to appropriately respond to the occurrence of a failure.

In addition, if a false alarm is issued, the failure determination results can be used to determine whether the false alarm is due to the deterioration of the UV detector tube, and appropriate measures can be taken by knowing the misreport. And the reliability of the flame monitoring device can be improved.

Block diagram showing an embodiment of a flame monitoring device according to the present invention used as an arson sensor Explanatory drawing which showed the discharge operation of the ultraviolet ray detection tube when the ultraviolet ray incidence of the flame to be monitored and the flame judgment threshold are changed for this Time chart showing the operation of the flame monitoring device of FIG. Explanatory diagram showing the relationship between the flame duration of the flame to be monitored and the discharge operation of the UV detector tube when the flame determination threshold is changed while the oscillation pulse signal period is fixed The flowchart which showed the processing operation in the case of execution of the program of a computer circuit for the flame determination and failure determination of FIG. The block diagram which showed other embodiment of the flame monitoring apparatus by this invention used as a flame detector

[Configuration of flame monitoring device]
FIG. 1 is a block diagram showing an embodiment of a flame monitoring apparatus according to the present invention, taking as an example a case where flame is monitored as an arson sensor.

  In FIG. 1, the flame monitoring apparatus of the present invention includes an oscillation unit 10, an ultraviolet ray detection unit 12, a flame determination unit 14, a failure determination unit 16, a battery power supply 18, and a wireless communication unit 20.

  The battery power source 18 uses, for example, a lithium battery and operates by supplying, for example, DC 5V to each unit.

  The oscillation unit 10 includes an oscillation circuit 22 and a high voltage generation circuit 24. The oscillating unit 10 generates a synchronous pulse signal a having a pulse width of, for example, several microseconds at a predetermined period T2, and outputs it to the high voltage generation circuit 24. The high voltage generation circuit 24 uses a booster circuit or the like, and outputs a high voltage set in the range of 300 to 500 V to the ultraviolet detection unit 12 in synchronization with the synchronization pulse signal a. Although the synchronization pulse signal a from the oscillation circuit 22 is also supplied to the flame determination unit 14 and the failure determination unit 16 for operation, the illustration is omitted.

  The ultraviolet detection unit 12 includes an ultraviolet detection tube 26. The ultraviolet ray detection tube 26 has an anode and a cathode disposed in a glass tube that transmits ultraviolet rays and encloses a special gas. For example, a commercially available UVtron (R) is used. The output of the high voltage generation circuit 24 is connected to the anode terminal of the ultraviolet ray detection tube 26 via the resistor R1, the resistor R2 and the capacitor C are connected in parallel to the cathode terminal, and a flame determination unit is interposed between the cathode terminal and the resistor R2. 14 is connected to output an ultraviolet detection pulse signal b.

  The ultraviolet ray detection tube 26 discharges when an ultraviolet ray having an intensity exceeding a predetermined discharge start level is applied from the outside in a state where a high voltage is applied from the oscillation unit 10 in synchronization with the synchronization pulse signal a, and the resistor R1, ultraviolet ray A discharge current is caused to flow in a pulse manner through a path that becomes the detection tube 26 and the resistor R2, and ultraviolet detection pulse signals b generated at both ends of the resistor R2 are output to the flame determination unit 14.

  The ultraviolet ray detection tube 26 causes self-discharge at a certain time interval when a high voltage is applied even if no ultraviolet ray is incident. The self-discharge time interval differs depending on the ultraviolet detection tube used and is generally said to be on the order of several minutes, but varies.

  Further, as the UV detector tube 26 deteriorates, the number of self-discharges increases. Further, the ultraviolet ray detection tube 26 causes discharge in response to factors in the natural world such as sunlight, welding light, plasma, radiation, and cosmic rays in a state where a high voltage is applied even if no ultraviolet ray is incident. Since discharge due to factors in the natural world becomes background noise, it is hereinafter referred to as noise discharge.

  As described above, the ultraviolet ray detection tube 26 has self-discharge and noise discharge in addition to the discharge due to the original ultraviolet ray detection due to the ultraviolet ray incident from the flame, and the self-discharge and noise discharge are uncertain discharges, and the ultraviolet rays output by the discharge. The detection pulse signal b includes those due to self-discharge and noise discharge, and even if processed as it is, the flame cannot be accurately determined.

  The flame determination unit 14 determines that the flame is detected when the continuous output number N of the ultraviolet detection pulse signal b matches a predetermined flame determination threshold Nth, outputs the flame determination signal c to the wireless communication unit 20, and transmits it to the alarm device. Alarm. Therefore, the flame determination unit 14 includes a gate circuit 28, a shift register 30, and a continuous number determination unit 32.

  The gate circuit 28 operates in response to the synchronization pulse signal a from the oscillation circuit 22, and outputs a bit signal of logic level 1 when the ultraviolet detection pulse signal b is input, and outputs a logic signal when the ultraviolet detection pulse signal b is not input. A level 0 bit signal is output.

  The shift register 30 has a shift stage number corresponding to the flame determination threshold value Nth, operates in accordance with the synchronization pulse signal a, and sequentially shifts the bit signals from the gate circuit 28.

  The continuity number determination unit 32 receives the bit signals of the respective shift stages of the shift register 30, and when all the bit signals become logic level 1, that is, the continuity of the ultraviolet detection pulse signal b output from the ultraviolet detection unit 12. When the output number N matches the flame determination threshold Nth, the flame is determined and the flame determination signal c is output to the wireless transmission unit 20 for transmission. As the continuous number determination unit 32, an AND gate that inputs a bit signal of each shift stage of the shift register 30 in parallel and outputs a logical product can be used.

  The flame determination unit 14 is not limited to the configuration of the gate circuit 28, the shift register 30, and the continuous number determination unit 32, and the output of the ultraviolet detection pulse signal b output from the ultraviolet detection unit 12 is compared with the flame determination threshold Nth. If it can be determined as a flame, it can be configured appropriately.

  The failure determination unit 16 includes a timer circuit 34, a counter 36, and a count determination unit 38. The counter 36 counts a logical level 1 bit signal corresponding to the ultraviolet detection pulse signal b output from the gate circuit 28 at every predetermined failure determination time T3 set by the timer circuit 34, and from this, the ultraviolet detection tube 26 The number of discharges K is detected.

  The count determination unit 38 inputs the number K of discharges counted by the counter 36 to determine a discharge stop failure due to the failure of the oscillation circuit 22, the high voltage generation circuit 24 and / or the ultraviolet detection tube 26, and the deterioration of the ultraviolet detection tube 26. The failure determination signal d or the deterioration determination signal e is output to the wireless communication unit 20 and transmitted to the alarm device.

  The failure determination unit 16 is not limited to the configuration of the timer circuit 34, the counter 36, and the count determination unit 38, and the number of discharges K is set for each failure determination time T3 based on the ultraviolet detection pulse signal b output from the ultraviolet detection unit 12. If it is possible to detect the discharge stop failure due to the failure of the oscillation circuit 22, the high voltage generation circuit 24 and / or the ultraviolet ray detection tube 26 and the deterioration of the ultraviolet ray detection tube 26 from the detected number K of discharges, an appropriate configuration may be adopted. it can.

[Principle of flame judgment and how to determine the flame judgment threshold]
(Principle explanation)
Next, the principle of flame determination according to the present invention will be described by taking as an example the case of determining a small flame by a writer for arson monitoring.

  In arson monitoring, for example, it is required to determine a flame when a writer is turned on at a position where the monitoring distance is several meters. Here, the time during which the ultraviolet rays from the flame to be monitored continuously enter the ultraviolet detection tube 26 is defined as the flame duration T1. When firing with a writer, it is assumed that the writer is turned on and off several times to try to ignite it. Therefore, the flame duration T1 of the flame caused by one ignition of the writer is several meters away. For example, when it is set to 5 meters, it is about several hundred milliseconds, and for example, the flame duration T1 is set to T1 = 500 milliseconds.

  In the present invention, the flame duration T1 is divided into a plurality of times, and an ultraviolet ray detection operation (high voltage application) is performed by the ultraviolet ray detection tube 26 at each divided time, and the ultraviolet ray detection tube 26 is discharged at each division time. If it is continuous, the flame is judged. This flame determination substantially means that the flame is determined by detecting the flame duration of the flame to be monitored.

  Therefore, the number of divisions of the flame duration T1 becomes a flame determination threshold value Nth for determining a flame from the number N of continuous outputs of the ultraviolet detection pulse signal, and a value obtained by dividing the flame duration T1 by the flame determination threshold value Nth (T1 / N ) Is the period T2 of the synchronization pulse signal a oscillated by the oscillation unit 10.

(How to determine the flame judgment threshold)
The number of divisions of the flame continuation time T1, that is, the flame determination threshold Nth, is such that noise discharge due to self-discharge of the ultraviolet ray detection tube 26 or the natural world is a single occurrence, so if it is at least divided into two (Nth = 2), The original discharge due to flame can be distinguished from self-discharge and noise discharge. However, if the number of divisions is small, the degree of misjudgment of flames due to self-discharge or noise discharge increases, so the number of divisions is divided into three (Nth = 3), four (Nth = 4), and five (Nth = 5). ), The degree of misjudgment of flame can be lowered.

  On the other hand, when the number of divisions is increased in order to suppress erroneous determination, the cycle of the synchronization pulse signal a generated in the oscillation circuit 22 is shortened, and the number of operations of the circuit unit that is operating by supplying the synchronization pulse signal a is increased. However, current consumption increases and battery life is shortened. Therefore, an optimum number of divisions, that is, a flame determination threshold value Nth is determined in consideration of erroneous determination of flame and an increase in current consumption.

  FIG. 2 is an explanatory diagram showing flame determination when the flame determination threshold Nth is set to Nth = 2, 3, 4, 5 for a flame with a flame duration time T = 500 milliseconds by the writer.

  First, the ultraviolet light incident on the ultraviolet ray detection tube 26 from the flame of the writer to be monitored has a flame duration time T1 = 500 milliseconds that exceeds the predetermined discharge start level at times t1 to t2.

  When the flame determination threshold Nth = 2 is set, the period T2 of the synchronization pulse signal a is T2 = 250 milliseconds by dividing the flame duration T1 = 500 milliseconds by the flame determination threshold Nth = 2. The ultraviolet ray detection tube 26 is continuously discharged twice at an interval of 250 milliseconds when the ultraviolet ray having a flame duration T = 500 milliseconds is incident from time t1, and the number of continuous outputs of the ultraviolet ray detection pulse signal b is determined as a flame. A flame is determined by detecting that the threshold value Nth = 2.

  When the flame determination threshold Nth = 3, the period T2 of the synchronization pulse signal a is T2 = about 167 milliseconds, and the ultraviolet ray detection tube 26 is irradiated with ultraviolet rays having a flame duration T = 500 milliseconds from time t1. The battery is discharged three times continuously at an interval of about 167 milliseconds, and the flame is determined by detecting that the number of continuous outputs of the ultraviolet detection pulse signal b matches the flame determination threshold Nth = 3.

  When the flame determination threshold Nth = 4, the period T2 of the synchronization pulse signal a is T2 = 125 milliseconds. When the ultraviolet ray having a flame duration T = 500 milliseconds is incident from time t1, the ultraviolet ray detector tube 26 is continuously discharged four times at intervals of 125 milliseconds, and the number of continuous outputs of the ultraviolet ray detection pulse signal b is the flame determination threshold value. A flame is determined by detecting that Nth = 4.

  Further, when the flame determination threshold Nth = 5, the period T2 of the synchronization pulse signal a is T2 = 100 milliseconds. When the ultraviolet ray of the flame duration T = 500 milliseconds is incident from the time t1, the ultraviolet ray detection tube 26 is continuously discharged five times at an interval of 100 milliseconds, and the number of continuous outputs of the ultraviolet ray detection pulse signal b is the flame determination threshold value. A flame is determined by detecting that Nth = 5.

  Actually, the dischargeable timing of the ultraviolet ray detection tube 26 determined by the flame duration T1 of the time t1 to t2 when the ultraviolet ray exceeding the discharge start level emitted from the flame is incident and the period T2 of the synchronous pulse signal a (high A time lag occurs with respect to the voltage application timing. However, even if there is this time lag, the number of synchronization pulse signals a corresponding to the flame determination threshold value Nth is always included in the flame duration T1, and if ultraviolet rays are incident during the flame duration T1, the flame determination threshold value Continuous discharge can be performed a number of times determined by Nth.

  Here, when the flame determination threshold value is Nth = 2, that is, when the number of continuous discharges of the flame determination is two times, the flame is erroneously detected due to self-discharge or noise discharge of the ultraviolet ray detection tube 26 that occurs once. There is a problem that the degree of determination becomes high.

  Therefore, if the flame determination threshold Nth is increased and the number of consecutive flame determinations is increased, the degree of erroneous determination of flame decreases. However, for example, when Nth = 5 and the number of continuous discharges of the flame determination is five, the period T2 of the synchronization pulse signal a is as short as T2 = 100 milliseconds, and the circuit unit that operates in response to the synchronization pulse signal operates. There is a problem in that the number of operations increases and the current consumption increases accordingly.

  Therefore, the flame determination threshold Nth is appropriately set in consideration of both the erroneous determination of the flame and the increase in current consumption. Here, for example, Nth = 4 is determined with emphasis on avoidance of erroneous flame determination. Therefore, when the flame of the writer whose flame duration time T1 = 500 milliseconds is to be monitored and the flame determination threshold Nth = 4 is determined, the period T2 of the synchronization pulse signal is T2 = 125 milliseconds.

  Specifically, the period T2 of the synchronization pulse signal a generated in the oscillation circuit 22 is set to T2 = 125 milliseconds, the shift register 30 is a four-stage shift register corresponding to the flame determination threshold Nth = 4, The continuous number determination unit 32 is a 4-input AND gate.

(Fire monitoring operation)
FIG. 3 is a time chart showing the flame monitoring operation in the embodiment of FIG. 1 when the flame duration T1 = 500 milliseconds, the flame determination threshold Nth = 4, and the synchronization pulse signal period T2 = 125 milliseconds. is there.

  FIG. 3 (A) shows the intensity of ultraviolet light incident on the ultraviolet detection tube 26 from the outside, and the synchronization generated at the period T2 in FIG. 3 (B) in a state where ultraviolet light having an intensity exceeding the discharge start level is input. When a high voltage based on the pulse signal a is applied, the ultraviolet detection tube 26 is discharged, and an ultraviolet detection pulse signal b shown in FIG. 3C is output.

  Since the ultraviolet ray detection pulse signal b is output at time t1 when no ultraviolet ray exceeding the discharge start level is incident, this is a self-discharge of the ultraviolet ray detection tube 26. In this case, the content of the shift register 30 shown in FIG. 3D is “1000”, and the logical product output by the continuous number determination unit 32 is bit 0, and is not determined to be a flame.

  At time t2 to t3, ultraviolet light having an intensity exceeding the discharge start level is incident from the writer flame, and the ultraviolet ray detection tube 26 is continuously discharged in synchronization with the oscillation pulse signal a. Output continuously. Therefore, the content of the shift register 30 changes to “1000”, “1100”, “1110”, “1111”, and the logical product by the continuous number determination unit 32 based on the input from the shift register 30 by the fourth continuous discharge. The output is bit 1 and the flame is determined.

  Times t4 and t5 are cases where the ultraviolet ray detector tube 26 has been subjected to noise discharge due to natural background noise, both of which are single discharge operations, and the contents of the shift register 30 are “1000” and “1001”. The logical product output by the determination unit 32 is bit 0 and is not determined to be a flame.

(Failure judgment operation)
Next, the operation of the failure determination unit 16 will be described. The timer circuit 34 provided in the failure determination unit 16 starts resetting the counter 36 every predetermined failure determination time T3. The failure determination time T3 is set to T3 = 5 minutes, for example.

  The counter 36 counts the bit signal of logic level 1 corresponding to the ultraviolet detection pulse signal b output from the gate circuit 28 during the failure determination time T3 to detect the number K of discharges of the ultraviolet detection tube 26, and the count determination unit 38. Here, the counter 36 does not detect the amount of ultraviolet rays, but only detects the number K of discharges including the discharge due to ultraviolet rays of the ultraviolet ray detection tube 26, self-discharge, and noise discharge caused by the natural world.

  In the conventional flame monitoring apparatus, the number of discharges is counted every predetermined time with the same configuration as the timer circuit 34 and the counter 36, and this count value is regarded as the amount of ultraviolet rays, and is equal to or greater than a predetermined flame determination threshold value. In the present invention, as described in detail in the above description of the principle, such a flame determination is not performed. Can be understood to be basically different.

  The count determination unit 38 determines a discharge stop failure in which the discharge of the ultraviolet ray detection tube 26 stops and the deterioration of the ultraviolet ray detection tube 26 from the number of discharges K input as the count value. Here, for the discharge stop failure of the ultraviolet ray detection tube 26, besides the failure of the ultraviolet discharge tube 26, the failure of the oscillation circuit 22 that generates the synchronization pulse signal a necessary for the discharge operation, the high voltage generation circuit that generates the high voltage 24 failures are included.

  When the counted number K of discharges is K = 0, the count determination unit 38 determines a discharge stop failure and outputs a failure determination signal d to the wireless communication unit 20 to be transmitted to the alarm device.

  In the self-diagnosis unit provided in the conventional flame monitoring device, when the number of discharges is equal to or greater than a certain number of times, it is determined that the ultraviolet discharge tube 26 is normal. Although it is determined to be abnormal, it is different in that it does not directly determine a discharge stop failure in which the ultraviolet discharge tube 26 does not discharge at all. Even if the number of discharges is less than a certain number and the abnormality of the ultraviolet ray detection tube 26 is judged, if the number of discharges is even one, the ultraviolet ray detection tube 26 is in a state where discharge operation is possible, and ultraviolet rays from the flame are incident. In this case, there is a possibility that the flame is correctly determined and an alarm is left, and the failure determination accuracy is low in that the discharge stop failure is not determined as in the present invention.

  The count determination unit 38 determines the deterioration of the ultraviolet ray detection tube 26 when the counted number K of discharges is equal to or greater than a predetermined deterioration determination threshold value Kth. The degradation determination threshold value Kth is set to a range of less than 2400 times that is at least once and the failure determination time T3 = the maximum number of discharges Kmax of 5 minutes. In this case, it is desirable that the number of discharges at the time of shipment or installation of the flame monitoring apparatus is the minimum number of discharges Kmin including self-discharge and noise discharge, and the deterioration determination threshold value Kth is set in a range exceeding the minimum number of discharges Kmin.

The deterioration determination threshold value may be set in multiple stages. For example, the deterioration threshold is set in two stages, Kth = 800, Kth2 = 1600,
Kmin <K ≦ 800
800 <K ≦ 1600
1600 <K <2400
In accordance with the increase in the number of discharges, the degree of deterioration is determined as being divided into low, medium, and high corresponding to each range.

  In this way, by setting the deterioration determination threshold value in multiple stages, it is possible to determine the degree of deterioration from the increase in the number of self-discharges of the ultraviolet ray detection tube 26 and warn, and repair such as replacement of the ultraviolet ray detection tube 26, It is possible to appropriately perform before false alarms occur frequently due to deterioration.

  In addition, when investigating the false alarm of the flame monitoring device by visiting the site, the cause of the false alarm may be caused by checking the determination result of the failure determination unit 16 and the number of discharges K counted by the counter 36. It is possible to easily determine whether it is caused by deterioration or other background noise, and it is possible to narrow down the cause of false alarms.

[Change of flame judgment threshold]
In the flame monitoring apparatus of the present invention, as shown in FIG. 2 , for example, flame determination is performed with a flame duration T1 = 500 milliseconds, a flame determination threshold Nth = 4, and a synchronization pulse signal period T2 = 125 milliseconds. FIG. 4 shows the flame determination when the flame determination threshold Nth = 4 is changed to Nth = 3 or Nth = 5, for example, while the period of the synchronization pulse signal a is fixed at T2 = 125 milliseconds. The description will be as follows.

  FIG. 4A shows the flame determination of the embodiment of FIG. 1 with the flame determination threshold Nth = 4. The flame duration T1 of the flame to be monitored is T1 = T2 × Nth = 125 × 4 = 500 mm. Second, the flame is judged from four consecutive discharges.

  FIG. 4B shows a case where the flame determination threshold value is decreased by 1 and Nth = 3, and the flame duration T1 of the flame to be monitored is T1 = 125 × 3 = 375 milliseconds, which is three consecutive times. The flame is discriminated from the discharge.

  FIG. 4C shows a case where the flame determination threshold value is increased by 1 and Nth = 5, and the flame duration T1 of the flame to be monitored is T1 = 125 × 5 = 625 milliseconds, which is 5 consecutive times. The flame is discriminated from the discharge.

  Here, when the flame determination threshold value is reduced to Nth = 3, if there is no change in the monitoring distance, the reduction in the flame duration time T1 means that the detectable flame is reduced, and this indicates the detection sensitivity. It will be raised. Further, if there is no change in the size of the flame to be monitored, the fact that the flame duration time T1 has become short means that the monitoring distance has become long. This is because when the monitoring distance is increased, the time of the ultraviolet intensity exceeding the dischargeable level is reduced due to attenuation even in the same flame.

  Further, when the flame determination threshold is increased to Nth = 5, if there is no change in the monitoring distance, an increase in the flame duration T1 means that the detectable flame is increased, and this increases the detection sensitivity. It is lowered. Further, if there is no change in the size of the flame to be monitored, an increase in the flame duration T1 means that the monitoring distance has become shorter.

  As described above, in the flame monitoring apparatus of the present invention, the flame determination threshold Nth, that is, the discharge for determining the flame, with the period T2 of the synchronization pulse signal for setting the dischargeable timing of the ultraviolet ray detection tube 26 fixed. By changing the number of consecutive times, the detection sensitivity and the monitoring distance can be easily changed.

[Modification of the present invention]
(Computer circuit)
As another embodiment of the present invention, a computer circuit having a CPU, a memory, and various input / output ports is provided, and the flame determination unit 14 and the failure determination unit 16 of FIG. You may do it. In this case, generation of the synchronization pulse signal a by the oscillation circuit 22 can also be performed by a computer circuit.

  FIG. 5 is a flowchart showing flame monitoring processing when a computer circuit is provided. In FIG. 5, when it is determined in step S1 (hereinafter “step” is omitted) that the oscillation circuit 22 (which may be a program execution function) generates the synchronization pulse signal a, the process proceeds to S2, and the ultraviolet detection pulse due to the discharge of the ultraviolet detection tube 26. The presence or absence of the signal b is determined.

  If it is determined in S2 that there is an ultraviolet detection pulse signal, the process proceeds to S3, and bit 1 is written in the memory. In S4, the latest continuous Nth bits, for example, 4 consecutive bits are read from the memory. The flame is determined and a flame determination signal is transmitted from the wireless communication unit 20. If it is determined in S2 that there is no ultraviolet detection pulse signal, the process proceeds to S6, bit 0 is written in the memory, and the process proceeds to S7.

  In S7, whether or not the failure determination time T3 has elapsed is determined while counting the number of discharges K by counting the ultraviolet detection pulse signal. When the failure determination time T3 has been determined, the flow proceeds to S8, where failure determination processing is performed. I do.

  In this failure determination process, if the number of discharges K is K = 0, a discharge stop failure is determined and a failure determination signal is transmitted from the wireless communication unit 20. If the number of discharges K is equal to or greater than the deterioration threshold Kth, the deterioration of the ultraviolet detection tube 26 is determined, and a deterioration determination signal is transmitted from the wireless communication unit 20. In this case, the deterioration determination may be performed by setting the threshold value in multiple stages and determining the degree of deterioration.

(Flame detector)
FIG. 6 is a block diagram showing another embodiment of the present invention used as a flame detector. In FIG. 6, the flame monitoring device is provided with a non-polarization unit 40, a constant voltage unit 42, a transmission circuit unit 44, and an operation display unit 46 in order to connect a sensor line from the receiver. The unit 10, the ultraviolet detection unit 12, the flame determination unit 14, and the failure determination unit 16 are the same as those in the embodiment of FIG.

  The depolarization circuit unit 40 depolarizes the connection polarity of the terminals L and C with respect to the sensing line from the receiver. The flame monitoring device receives a voltage supply of, for example, DC 24V from the receiver, converts it to, for example, DC 5V by the constant voltage unit 42, and supplies it to each unit.

  When the flame determination signal c is input from the flame determination unit 14, the transmission circuit unit 44 transmits a flame determination signal to the receiver, for example, by operating a switching circuit to flow a predetermined flame determination current (reporting current). To do. At this time, a current also flows through the operation display unit 46, and an operation indicator lamp such as an LED is turned on.

In addition, when the failure determination signal d or the deterioration determination signal d is input from the failure determination unit 16, the transmission circuit unit 44 operates the switching circuit to flow a predetermined failure determination current or deterioration determination current different from the flame determination current. Then, each determination signal is transmitted to the receiver.

  When used as a flame detector, the monitoring distance is, for example, 20 to 30 meters, and the flame to be monitored is a relatively large flame that continues due to a fire. The flame is determined by determining the flame determination threshold Nth and the period T2 of the synchronization pulse signal.

  For example, as shown in FIG. 5, the period T2 of the synchronization pulse signal is fixed at T2 = 125 milliseconds, and the flame duration T1 is determined to determine the flame due to fire without determining the writer's flame due to smoking. For example, when T1 = 2500 milliseconds (= 2.5 seconds), the flame determination threshold Nth is set to Nth = 20, and 20 consecutive discharges are detected to determine the flame.

  Further, as a flame determination for use as another flame detector, the flame determination in FIG. 1 is not changed, and a fire is determined by detecting the number of continuous discharges four times by the continuous number determination unit 32 (500 milliseconds). The flame determination result is accumulated, and when it is detected that the flame has been output four times in succession (2500 milliseconds = 2.5 second flame determination), the flame determination is confirmed and the flame determination signal is sent. You may make it transmit to a receiver.

  The accumulation in this case is accumulated when viewed from the flame determination with the flame duration T1 = 500 milliseconds. However, the accumulation in this case is the flame determination with the flame duration T1 = 2500 milliseconds as the original fire detector. Therefore, it is necessary to note that the accumulation does not occur, and the flame determination according to the present invention is not accumulated as in the conventional apparatus.

(Other)
For a flame monitoring device that operates from a battery power source, a low battery failure in which the battery voltage drops below a predetermined voltage may be detected and alarmed.

  In addition, the flame monitoring device of the above embodiment is a device that transfers information to an external receiver or the like when a flame or failure is detected. An alarm may be given by voice or voice.

The present invention is not limited to the above-described embodiment, includes appropriate modifications that do not impair the object and advantages thereof, and is not limited by the numerical values shown in the above-described embodiment.

10: Oscillator 12: UV detector 14: Flame determiner 16: Fault determiner 18: Battery power supply 20: Wireless communication unit 22: Oscillator 24: High voltage generator 26: UV detector 28: Gate circuit 30: Shift Register 32: Continuous number determination unit 34: Timer circuit 36: Counter 38: Count determination unit 40: Depolarization unit 42: Constant voltage unit 44: Transmission circuit unit 46: Operation display unit

Claims (5)

A synchronization pulse signal having a period (T2) as a quotient (T1 / Nth) obtained by dividing a predetermined flame continuation time (T1) in which ultraviolet rays from a flame to be monitored continuously enter by a predetermined flame determination threshold (Nth) An oscillation unit that generates
An ultraviolet ray detector that includes an ultraviolet ray detector tube, and outputs an ultraviolet ray detection pulse signal by a discharge operation of the ultraviolet ray detector tube when an ultraviolet ray is incident from the outside in a voltage application state based on a signal of the oscillation unit;
A flame determination unit that determines a flame and outputs a flame determination signal when the number of continuous outputs (N) of the ultraviolet detection pulse signal matches the flame determination threshold (Nth) ;
A failure determination unit that counts the ultraviolet detection pulse signal over a predetermined failure determination time, determines a failure of the ultraviolet detection unit based on the count value, and outputs a failure determination signal;
The flame monitoring apparatus characterized by providing.
In the flame monitoring apparatus according to claim 1,
A flame monitoring apparatus , wherein a detection sensitivity or a monitoring distance can be changed by changing the flame determination threshold value while fixing a synchronization pulse signal generated in the oscillation unit at a predetermined period.
In the flame monitoring apparatus according to claim 1,
The failure monitoring unit determines and outputs a discharge stop failure of the ultraviolet ray detection tube when the count value is zero, and outputs the failure.
In the flame monitoring apparatus according to claim 1,
The failure determination unit, when the count value is greater than zero and not less than a predetermined failure determination threshold set in a range less than the maximum count value when the ultraviolet detection pulse signal is continuously output over the failure determination time In addition, a flame monitoring apparatus characterized in that deterioration of the ultraviolet ray detection tube is judged and outputted.
In the flame monitoring apparatus according to claim 4,
The failure determination unit determines and outputs the degree of deterioration of the ultraviolet detection tube by setting the failure determination threshold in a plurality of stages and comparing the failure determination threshold with the count value.

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