JPS6239473B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a first current circuit for receiving flickering frequency components of the flame radiation in the wavelength range of at least the resonant radiation of carbon dioxide by means of photoelectric means and a bandpass filter to generate a valid signal for the alarm means. Regarding a detection device. As is generally well known, most combustible materials, such as wood, benzene, oils and hydrocarbons or carbohydrates, in other words organic compounds, have a diameter of about λ=2.7 μm and especially about λ=4.4 When burned, it generates strong radiation in the wavelength range of about μm. Radiation takes place in the line and band spectra and in water and
For _CO2 , the wavelength range of 2.7 μm is characteristically correlated, and for carbon dioxide, the wavelength range of 4.3 μm is characteristically correlated. Magazine “Report of Fire Research” published in December 1969
Institute of Japan)” Volume 30, No. 55 to 60
The paper “Fire Detection by Intrared Resonance” published on page
In particular, FIG. 6 shows a flame radiation and temperature sensitive alarm or detector circuit. This detector is configured for the infrared region. However, this detector suffers from security deficiencies against false alarms. In the presence of disturbing radiation in the infrared range, e.g. from hot objects or furnaces where the thermal radiation is interrupted at certain times by a ventilator etc., alarms or detection may occur even in the absence of a flame. The device may generate an alarm, which is of course undesirable. In the device described in French Patent No. 2,151,148, two wavelength ranges or bands are evaluated for issuing an alarm in the event of a fire. The selectivity is determined by the arrangement of two narrow band optical filters that are transparent only for two wavelength ranges λ=2.7 and λ=4.3 (μm). Photovoltaic voltages generated from these two wavelength ranges are evaluated in the event of a fire alarm. Experiments have shown that this detector also has a tendency to generate false alarms in the presence of interfering radiation sources of suitable color temperature, and therefore this detector also reduces the false alarm rate less effectively. I can't. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a flame detection device which can significantly reduce the rate of false alarms and can uniquely recognize each flame as a flame and issue a fire alarm despite the presence of interference sources. There is a particular thing. The present invention further provides approximately λ=4.4μ for alarm generation.
The present invention also contemplates the evaluation of radiation in the wavelength range m. Ordinary window panes and lamp glasses are not transparent to radiation in this wavelength range. Therefore, incident sunlight and normal electric light in the room where the alarm is installed will not affect the alarm generation of the alarm. The flame detection device according to the invention can also be installed in free space, ie outdoors. This is because, as is well known, there is a so-called energy gap in the radiation spectrum of sunlight at λ = 4.3 μm. In this case as well, the sun is excluded from the processing as a source of interference. Another object of the present invention is to prevent components in a wavelength range larger than 6 μm from having any influence on alarm generation. In this way, the effects of hot objects and furnaces are eliminated. Furthermore, the flame detection device of the invention is configured in such a way that no false alarms are generated in the case of interference radiation of hot objects below λ=6 μm. The detection device of the invention generates an alarm only when there is a flame emitting radiation in the wavelength range λ=4.4 μm. This alarm is also triggered when a hot object emits interfering radiation in the wavelength range λ=6 μm. In this case, it must be ensured that the alarm is generated when the disturbing radiation of the hot object is modulated approximately at the flicker frequency of the flame. This is because the probability of a perfect match is extremely low. In order to solve the objects and problems mentioned above, according to the invention, in the flame detection device mentioned at the outset, a second flame detection device provided with coupling means is provided for eliminating the interference radiation generated by the thermal radiator. a current circuit, the second current circuit comprising a filter having a predetermined wavelength passband and photoelectric means for receiving radiation having a wavelength above the resonant wavelength region of carbon dioxide to generate a disturbance signal; a further bandpass filter having the same interference radiation flicker frequency pass band as in said first current circuit for flicker frequencies and coupling circuit means for coupling said first and second current circuits; and the coupling circuit means prevents the transmission of the signal in the first current circuit when output signals of the same polarity appear simultaneously in the second current circuit, taking into account the statistical distribution of the flame radiation and interference radiation. and configured to generate an output signal in such a way that if the output signal of the second current circuit is absent or appears with a different polarity, the signal of the first current circuit is transmitted to the alarm means. A flame detection device is proposed which is characterized by: Next, embodiments of the present invention will be described with reference to the accompanying drawings. In FIGS. 1a, 1b and 1c, pulses A, B and C are shown on the time axis t. These pulses are the pulses that appear at nodes A, B, and C in the embodiments of FIGS. 9, 10, and 11. FIG. 1a shows that a pulse is generated in the first current circuit receiving the flickering frequency of the flame and a corresponding pulse is generated at node A of the embodiment shown in FIGS. 9, 10 and 11. This is an example of what is happening. In addition, in Figure 1a,
It is assumed that a disturbance signal is simultaneously received in the second current circuit and that a rectangular pulse appears at connection point B. Figure 9, Figure 10, Figure 1
The logic combination device, which will be described in more detail below in conjunction with the various embodiments shown in FIGS. 1, 12 and 13, is in this case configured so that it does not generate an output signal. In FIG. 1, this is represented by C=0. FIG. 1b shows the case in which a flame signal is generated in the first current circuit and a corresponding pulse is present at connection point A. In this case, at the same time, no disturbance signal is received in the second current circuit, and moreover, a disturbance pulse appears at the connection point B of the second current circuit, which does not coincide in time with the effective pulse at the connection point A. It is assumed that Under these conditions, the output point C of the logic combination device of the embodiments of FIGS. 9, 10 and 11 receives a signal only if a valid signal is present at the connection point A of the first current circuit. appears. FIG. 1c shows the presence of a useful signal due to the flame at connection point A of the first current circuit and the appearance of a time-delayed interference signal in the second current circuit (connection point B). show. Under this condition, the 9th
10 and 11, a valid pulse at connection point A and a simultaneous pulse at connection point B.
generates an output signal only if there are no interfering pulses present. FIG. 1c shows that the output pulse disappears at the connection point C of the logic combination circuit due to a certain temporal superposition of the two pulses mentioned above. FIG. 2 shows the intensity distribution of a typical flame spectrum. In the same figure, the horizontal axis shows the unit μ
The wavelength range λ is scaled with m, and the intensity in each wavelength range is shown on the vertical axis. As is clear from FIG. 2, there is a large spectrum in the wavelength region λ=4.4 μm. This is the wavelength region of carbon dioxide. This spectral distribution curve is 2.8 and 4.4
It has two clearly distinguishable maxima in μm. For λ>6 μm, the strength of the flame can be ignored. Figure 3 shows the spectral distribution of a hot object at about 300°C. In the figure, the horizontal axis is scaled with wavelength in μm, and the vertical axis is scaled with the radiation intensity of a certain interfering radiator. This interference radiator corresponds, for example, to a heat radiating device, such as a heating coil or a heating plate for cooking. It is assumed here that the radiation is periodically interrupted, for example by means of a ventilation device or ventilator. Such periodic interruptions, for example in the frequency range of 4 to 15 Hz, will be discussed in more detail below in connection with the embodiments of FIGS. 9, 10, 11 and 12. Another source of interference of the same type can be considered as exhaust pipes in internal combustion engine installations. This exhaust pipe is, as is known, loosely held and undergoes movements in the frequency range of approximately 5 to 15 Hz. 9th
This frequency is within the flame flicker frequency range, as discussed in more detail below in connection with FIGS. 10, 11, and 12. Interference sources of the above-mentioned type will be described in more detail below with reference to Figures 7a-7f and the associated tables, but for convenience of explanation are designated _S1 . Another type of interference source is the interference source shown in Figure 3.
There are heating objects or radiators or furnaces that have a radiation temperature that is essentially lower than S ₁ . Heating objects such as radiators and furnaces are denoted by S ₂ for convenience of explanation. This type of S ₂ disturbance source generates radiation in the wavelength range above 5.5 μm. It should be noted that even in this type of interference source _S2, for convenience it is assumed that the radiation is interrupted within the frequency range of 4 to 15 Hz. Such interruptions can then be caused, for example, by vibrations of a ventilator, objects installed in conjunction with the disturbance source, etc. It should be mentioned beforehand that in the embodiments of FIGS. 9 to 12, such disturbing emissions are not evaluated as disturbing emissions if they are not interrupted. A detailed explanation of this will be given in connection with the embodiments. The types of interference sources S ₁ and S ₂ will be explained in detail with reference to the tables described in connection with FIGS. 7 and 8. FIG. 4 shows the filter 1 of the two current circuits of the embodiments of FIGS. 9, 10, 11, and 12.
and 9 passbands are graphically displayed. Referring to FIG. 4, the first current circuit responsive to flame radiation is provided with a filter 1 having a wavelength passband of 4.4 μm. The filter 9 disposed in front of the second current circuit in the above embodiment is 6μ
It has a wavelength pass band larger than m. In FIG. 4, the filter 9, which passes interfering radiation, has a passband with a steeply rising edge in the vicinity of 6 μm and a gradually decreasing edge over a large wavelength range. Therefore, a relatively inexpensive filter can be used as the filter 9, and as shown in FIGS.
The embodiment shown in FIG. 2 works very well. FIG. 5 graphically represents the passbands of two useful signal current circuits of the first type and of a disturbance signal current circuit of the second type. The first current circuit is approximately 2.5
It has a filter 1 having a wavelength passband of μm. Another first current circuit comprises a filter 1 with a wavelength passband of 4.4 μm. The second current circuit comprises a filter 9 with a wavelength passband greater than 6 μm. Alternatively, three current circuits can be provided according to FIG. Of course, a larger number of current circuits may be provided. The embodiments shown in FIGS. 9 to 12 will be described on the assumption that only two current circuits are provided. The filter 9 of the second current circuit has a pass band with steep edges on both sides, as shown in FIG. Such a filter may have a fourth filter which may have a less sharply defined passband width.
It is relatively more expensive than the filter shown. It should be noted here that both expensive and inexpensive filters can be used in the embodiments described in detail below. FIG. 6 graphically shows the spectral distribution characteristics of normal sunlight. The wavelength λ is scaled in μm on the horizontal axis, and the magnitude of the spectrum is scaled in relative units on the vertical axis. As is clear from FIG. 6, the sunlight has a maximum value at a few characteristic points and a minimum value at a specific location. Of particular interest is the minimum value near 4.3 μm. FIG. 7 graphically illustrates the operation of the embodiment of FIGS. 9-12 in combination with the components shown in FIGS. 8 and 13. In the individual diagrams a, b, c, d, e and f of FIG. 7, the wavelength λ is taken on the horizontal axis in μm and the filter 1
The sizes of the passbands 9 and 9 are scaled in relative units on the vertical axis. Figure 7a shows the case where there is no flame and no interfering radiation. Therefore, no pulses or voltages appear at circuit points A and B in FIGS. 9, 10, 11 and 12. Therefore, no alarm is generated. Figure 7b shows the presence of a flame in the wavelength band of Figures 4 or 5. In this case, it is assumed that there is no interfering radiation. A pulse or voltage therefore appears at circuit point A of the first current circuit in the embodiment of FIGS. 9 to 12. However, no voltage is generated at circuit point B of the second current circuit. In this case an alarm will be generated. FIG. 7c shows the case in which interfering radiation in the wavelength range of FIG. 4 or FIG. 5 is present, while no flame is present. The disturbance source is assumed to be of type S ₂ , which according to the previous definition is approximately 100 °C
It may be a radiator heat radiator or a furnace or the like having a temperature of . In the case shown in FIG. 7c, no voltage appears at circuit A of the current circuit of FIGS. 9 to 12, but a voltage or pulse appears at circuit point B. In this case, no alarm is generated. Figure 7d shows a case where both a flame and a disturbance radiation of a disturbance source of type S ₂ are present. The wavelength range is selected according to FIG. 4 or FIG. 5. In this case, voltages or pulses appear at circuit points A and B of the current circuits of FIGS. 9 to 12. If voltages and pulses appear simultaneously at the circuit points A and B, no output signal is transmitted to the circuit point C via the logical combination circuits 18, 26 and 59 with inverters 17, 25 and 58. However, the flame and jamming radiation flicker over a wide frequency range of 4 to 15 Hz, so that at circuit points A and B the flame and jamming radiation signals sometimes appear synchronously (7.
(see Figure 7d) or may not appear synchronously (see Figures 7b or 7c). During such a state, an intermediate situation therefore arises in which the voltages or pulses at circuit points A and B partially overlap. In this case as shown in FIG. 1c, an unambiguous alarm signal also occurs at circuit point C. In this way it is ensured that the flame will trigger an alarm even in the presence of interfering radiation. FIG. 7e shows a case in which the disturbing radiation of the disturbing radiation type S ₁ is emitted over a very wide wavelength range. about
Such a disturbance emitting device, which can be a heat emitting device (heating coil or heating plate) with a radiation temperature of 300° C., includes not only the circuit for receiving the disturbance radiation (filter 9) but also the circuit shown in FIGS. 9 to 12. This also affects the flame detection circuit of the embodiment. This therefore means that synchronous voltages or pulses are applied to circuit points A and B. This is part 1a
Corresponds to the case of figure. As a result of this synchronization between the active voltage and the disturbance voltage, no alarm signal is generated at the output point C of the logical combination circuit means 18, 26 and 59. But this is appropriate since there is no flame. For clarity of understanding, in FIG. 7e, the interference radiation signal component reaching the logical combination circuit via the first current circuit (effective signal circuit) is designated by A'. Another example is shown in Figure 7f. In this case, there is a flame and at the same time there is interference radiation of type S ₁ . The signal component caused by the disturbing radiation and transmitted to the first current circuit is
It is represented by A′. The disturbing radiation component reaching via the second current circuit is also indicated by B. Since both components are caused by the same disturbance source, they are in sync. That is, voltages or pulses appear simultaneously at circuit points A and B. Therefore, no alarm signal is generated at the output point C of the logical combination circuit of FIGS. 9 to 12 due to these disturbing radiation components A' and B.
This is similar to the case shown in FIG. 7e. The flame in the case of FIG. 7f generates a voltage or pulse that appears at circuit point A in the embodiment of FIGS. 9 to 12 simultaneously or asynchronously with the disturbing radiation components A' and B. Logic combination circuit 18 generates an alarm signal when a voltage or pulse corresponding to a flame is applied at circuit point A and at the same time there is no voltage signal at circuit point B due to interfering radiation. In this case, the detector will issue an alarm after a certain waiting period has elapsed. To provide a clear overview of the various cases in Figures 7a to 7f, the following table is provided. The numbers written in the notes column in the table have the following meanings. 1 No flame is present and no alarm pulse is generated. 2 Flame is present and an alarm pulse is generated. 3 Monitoring status. 4 No interference. 5 There is interference. 6 A' and B occur simultaneously in time and C=
0, A=A+A'. 7 A and B do not occur at the same time and C=
1, A=A+A'.

[Table] FIG. 8 shows an example of the structure of a filter including the photoelectric means used in the embodiments of FIGS. 9 to 12. As is clear from FIG. 8, the filter 1 of the first current circuit is composed of a germanium or silicon layer 70, an interference filter 71 and a quartz layer 72. These various layers are present in a plane-parallel relationship, with the germanium layer 70 having a thickness of about 1 mm, the interference filter 71 having a thickness of about 1 to 50 μm, and the quartz layer 72 having a thickness of about 1 mm.
It is 0.5mm. The diameter of these layers or filters 1 is approximately 8 to 12 mm. Interference filter 71
can also be composed of multiple layers. Each layer is composed of dielectric material. layers 70, 71 and 7
The filter consisting of 2 is housed in a so-called "TO-5" type casing. Such casings are commercially available under the above trade names. The casing is connected to the filter via an adhesive connection 73. A sensing element 74, optionally with a field-effect transistor, can also be provided in the casing. This element serves to convert optical radiation into electrical signals. This signal is provided via conductor 75 to the circuitry of FIGS. 9-12. The sensing element 74 can be a pyroelectric detector, for example a lithium-tantalate, lead-selenide or lead-zirconate-titanate, or an NTC-thermistor or a photoconductor or a temperature-sensitive resistor. The filter or photoelectric means 1 or 2 of FIG.
This is provided for the first current circuit in the illustrated embodiment. The filter 9 for the second current circuit of the same embodiment may have a slightly modified construction. There is no quartz layer. Dimensions are the same as stated above.
Furthermore, the sensing element 74 is configured accordingly depending on whether it is used in the first current circuit or in the second current circuit. For example, one pyroelectric detector can be used for two current circuits. It is also possible to use NTC thermistors, photoconductors and temperature-sensitive resistors in the two current circuits. If the sensing element 74 is configured as a photovoltaic cell or a UV-sensitive gas-filled tube, the photovoltaic means 2 can be used only in the first current circuit. In this case, it is also possible to omit the filter consisting of layers 70, 71, 72. FIG. 9 shows a first embodiment consisting of two current circuits. The first current circuit is provided with a filter 1 and a photoelectric means 2, through which the wavelength range λ=4.1 to 4.8 μm is passed. This wavelength range is transmitted through the flame emission filter 1 by photoelectric means (8th
The sensing element 74) in the figure is selected to reach the sensing element 74), thereby generating a corresponding electrically effective signal. This useful signal is amplified in a subsequent amplifier 3. The amplified signal is indicated by reference numeral 53 in the lower part of FIG. Subsequent band filter 4
has a passband of flame flicker frequencies between 4 and 15 Hz. This is followed by an amplitude limiter 5 which slices the amplitude of the amplified signal 53 to generate a trapezoidal signal 54. This signal 54 reaches the differentiating element 6, which generates a voltage pulse 55 at the leading edge of the signal 54. The voltage pulse 55 is rectified in a subsequent rectifier 7 so that only one polarity differential voltage pulse 56 can reach the subsequent monostable multivibrator 8 . The multivibrator 8 generates pulses of the same amplitude and width. In this case the amplitude and pulse width are independent of the flame intensity. λ
A second current circuit with a filter 9 having a wavelength passband of =6 to 6.7 μm also corresponds to the first described above.
It is constructed in the same way as the current circuit. The amplifier 11 amplifies the electrical signal of the photoelectric element 10. Bandpass filter 12 likewise has a passband for the flickering frequency of the interference source in the range 4 to 15 Hz. The amplitude limiter 13, the differentiating element 14, the rectifier 15 and the monostable multivibrator 16 operate in the same way as already described in connection with the first current circuit.
The monostable multivibrator 16 generates a pulse 51 of constant amplitude and constant pulse width. The amplitude and pulse width of these pulses are not affected by the intensity of the radiation. In operation of the apparatus of FIG. 9, it is assumed that only flame radiation is present. In this case, the first current circuit generates a pulse 50 at circuit point A. The second current circuit does not generate a pulse at circuit point B (state=0). Subsequent inverter circuit 1
7 therefore generates a logic state "1". This logic state "1" reaches a logic combination circuit configured as an AND gate, which generates a pulse at its output C. This pulse is applied to a subsequent integrator 19. This integrator 19 is controlled by a timing element 20, e.g.
It will be reset after a specific time of 15 seconds. Since the AND gate 18 is a digital element, the integrator 19 is equipped with a counter for counting the minimum width output pulses C. A series of output pulses is applied to the counter, and when a predetermined threshold value preset in the counter is exceeded, the integrator 19 generates an alarm pulse to subsequent circuit sections. This alarm pulse is generated by the integrator only if the counter threshold is exceeded prior to reset by the current circuit 20. In order to prevent the alarm from occurring too early, for example within 2 seconds, a delay element 21 is provided.
This delay element delays the generation of the alarm pulse by a few seconds, so that the alarm device 22 is activated only if the alarm signal from the integrator 19 persists during this time. The operation of the circuit shown in Fig. 9 described above is shown in Fig. 7b.
Corresponds to the example shown in the figure. Therefore, next, the case shown in FIG. 7f will be briefly explained. Since there is a flame, the monostable multivibrator is connected to circuit point A.
A pulse 50 is generated. Furthermore, since a disturbance source of type S ₁ is present, the monostable multivibrator 16 also generates a pulse 51 at circuit point B. This pulse 5
1 occurs simultaneously with pulse 50. Further types S ₁
The disturbance source has a large radiation wavelength range, so that the disturbance radiation influences the first current circuit so that the monostable multivibrator 8 emits a pulse 5 at circuit point A.
Generates 0. The pulse 50 (see component A' in FIG. 7f) caused by the interfering radiation is always applied to circuit point B synchronously with the pulse 51. Because of the inverter 17, the AND gate 18 is blocked when these two pulses 50 and 51 are present synchronously. Since the flicker frequencies of the flame and interference radiation are statistically distributed with respect to each other, at circuit points A and B the pulse 5
0 and 51, so that the AND gate 18 is open for a large portion of time and passes the useful pulse 50 to the subsequent integrator 19. In this way, the generation of an alarm is guaranteed even in the presence of flames and disturbances. All the examples shown in FIG. 7 and the cases in the table that follows can be implemented using the embodiment of FIG. Note that 2 in Figure 9
A detailed explanation of the individual electronic circuit elements of the two current circuits is not necessary. This is because such circuit elements are known from the electronics literature. For example, please refer to the documents listed below. National Semiconductor Company (National
"Lynear Applications Handbook" Volume 1, February 1977 issue, published by Semiconductor Firma, McGraw-Hill Publishing, New York.
Applications of Operational Amplifiers, published in 1977 by John Hill Verag.
``Sourcebook of Electronic Circuits'' published by Dojosha in 1968. Swiss Patent Nos. 516761 and 558577. The embodiment of FIG. 10 is essentially similar in construction to the embodiment of FIG. The difference between these two embodiments is that the pulses appearing at circuit points A and B do not have a pulse width that is influenced by the flickering frequencies of the flame and interfering radiation. In the embodiment of FIG. 10, the pulse 41 is the vibration 4
It has a width that depends on the period of 0. The period of this oscillation 40 represents the flickering frequency of the flame or interfering radiation. The pulse width or duration of pulses 41 and 43 is determined by threshold 42 of comparators 30 and 31. The two current circuits have the same electronic components. Filters 1 and 9 have the same passbands as in the embodiment of FIG. The optoelectronic means 2 and 10, the amplifiers 3 and 11 and the bandpass filters 4 and 12 are constructed in the same way as already described. Comparators 30 and 31 follow bandpass filter 4 . The output signals of these comparators, shown at the top of FIG. 10, are applied to rectifiers 32 and 33. Then comparators 30 and 3
The operation mode 1 will be described in detail. The value of the output signal is as follows. If S _A (t)>ε, then a; If S _A (t)<ε, then -a In the above equation, S _A is the amplitude of the input signals of the two comparators 30 and 31, and ε is a threshold value. As is clear from the above equation, the same input signal S _A may exist for both the first current circuit (comparator 30) and the second current circuit (comparator 31). , then the output pulses of the two comparators have constant amplitudes +a and -a. The reason for providing the threshold value ε is to effectively suppress so-called noise in the two current circuits. and·
Elements 19, 20, 21 and 2 following gate 18
The operation mode of No. 2 is the same as that of the embodiment shown in FIG. In this example as well, the integrator 19 includes a counter having a predetermined threshold value. The counter is reset after a predetermined period of approximately 5 to 15 seconds. A signal is generated in delay element 21 if the counter exceeds its threshold before this reset. A capacitor is provided in the integrator 19 instead of the counter, and this capacitor is connected to the circuit point B of the second current circuit by the pulse 4.
3 is not present, it is sequentially charged by the pulse 41 passed through the AND gate 18. Furthermore, the inverter 17 outputs the inverted pulse 44 and
The AND gate applied to the second input of gate 18 and thus generating pulse 41 is blocked or opened from the first current circuit. The embodiment of FIG. 11 also includes two current circuits with electronic components similar to those described above. Bandpass filters 4 and 12 are followed by demodulators 38 and 39. Each of these demodulators consists of a rectifier 34 or 36 and a low pass filter 35 or 37.
These demodulators 38 and 39 are followed by comparators 30 and 31 and rectifiers 7 and 1.
5 is provided. By providing the demodulators 38 and 39, it is possible to form a demodulation envelope curve 46 of the rectified half-wave signal 45 from the flickering frequency 40 of the flame and interfering radiation. Such demodulators 38 and 39 are generally known from the literature and will not be described in detail. See, for example, the publications cited above. Comparators 30 and 31 are provided with a threshold value ε in the same manner as already described in connection with FIG. As shown in FIG. 7, the first current circuit generates a corresponding envelope curve 46 when a flame is present. At circuit point A, vibration of flame flickering frequency 45
A pulse 47 is generated whose width depends on the modulation envelope curve 46 that envelops the . However, pulse 4
The amplitude of 7 is always the same. In the presence of disturbing emissions of the various cases of FIG. 7, the second current circuit likewise generates a modulation envelope curve 46. Modulator 3
1, the threshold ε is taken into account. At circuit point B there is a pulse 4 whose width depends on a modulation envelope curve 46 that envelops an oscillation 45 of the flickering frequency of the disturbance radiation.
8 occurs. A subsequent inverter 17 generates an inverted pulse 49. AND gate 18 operates in the same manner as described in connection with the previous embodiment. The integrator 19 can be equipped with a counter or can have a capacitor. The formation of the threshold value and the time limit reset by the time limit circuit 20 have already been described. The fourth embodiment shown in FIG. 12 is similarly composed of two current circuits and a logic coupling circuit 26. The logic combination circuit 26 is configured as a phase comparator in this embodiment. Filters 1 and 9 have the same passbands as in the previously described embodiments. Similarly, the photoelectric means 2 and 10 are constructed equivalently. Amplifiers 3 and 11 amplify the signals.
Filters 4 and 12 pass only flicker frequencies in the range 4 to 15 Hz. Such oscillations in the flickering frequency range of flame and interference radiation are
It is indicated by the reference numeral 60 at the top of Figure 2. These vibrations are applied to threshold detectors 23 and 24. If a flame is present, an oscillation 61 appears at circuit point A of the first current circuit. In the presence of disturbing radiation, vibrations 6 are generated at circuit point B of the second current circuit.
2 appears. The vibration 62 is connected to the subsequent phase inversion circuit 2.
5 into vibration 63. The vibration signal 61 at circuit point A is applied to the rectifier 27 and the integrator 19 through the phase comparator 26 only if the signal 63 has the same polarity as the signal 61. In other words,
Signal 62 must be of a different polarity to signal 61. Note that the terms "same polarity" and "different polarities" herein mean that signals are applied to the two input terminals of the phase comparator 26 with the same sign at the same polarity and with different signs at different polarities. The operation mode up to the generation of the alarm via the integrator 19 and the delay element 21 is the same as described above. Finally, Figures 9, 10, 11 and 1
The embodiment of FIG. 2 may comprise a plurality of current circuits of a first type for the useful signal of the flare and a single current circuit of the second type for the interference signal of the interference source. I would like to add that it is possible. Each of the effective signal current circuits therefore has a different wavelength range, for example 4 to 4.8 μm, 3 to 3.8 μm.
m, 1.8 to 2.8 .mu.m, 0.7 to 1.7 .mu.m and/or 0.1 to 0.5 .mu.m, while the jamming signal current circuit operates in the wavelength range above 6 .mu.m, as shown for example in FIG. FIG. 13 shows another embodiment of a logic combination circuit for valid signal and interference signal current circuits. This logic combination circuit is formed as a NOR gate. That is, a NOR gate 59 is provided, one input of which is provided with an inverter 58. The operation modes of the logic coupling circuits 58 and 59 are shown in FIGS. 9 and 10.
and the logic coupling circuit 17, 1 of the embodiment of FIG.
8, so there is no need to explain it in detail here.

[Brief explanation of the drawing]

Figure 1a, Figure 1b and Figure 1c are Figure 9,
10 and 11 show the operation mode of the logic coupling circuit of the embodiment, FIG. 2 is a graph showing the spectral distribution in the wavelength region of a flame, and FIG. 3 is a graph showing a typical spectrum distribution in the wavelength region of a certain high-temperature object. 4 is a graph showing the passband characteristics of filters 1 and 9 used in the two current circuits of the embodiment of the present invention, and FIG. FIG. 6 is a graph showing the passband characteristics of the disturbance signal current circuit; FIG. 6 is a graph showing the spectral distribution characteristics as a function of the wavelength of solar radiation; FIG. FIG. 8 is a schematic cross-sectional view showing an example of the structure of a filter and a photoelectric device; FIG. 9 is a schematic diagram of the entire electrical circuit of an embodiment of the first flame detection device of the present invention partially embodied in digital form; 10th schematic diagram of the circuit shown in FIG.
FIG. 11 is a schematic circuit diagram showing a second embodiment of the flame detection device of the present invention realized in part in digital form;
12 is a circuit diagram showing a third embodiment of a flame detection device partially realized in digital form; FIG. 12 is a circuit diagram showing a fourth embodiment of a flame detection device partially realized in analog form. Schematic Diagram and FIG. 13 is a circuit diagram showing another embodiment of the logical combination circuit of FIGS. 9, 10, and 11. 1, 9... Filter, 2, 10... Photoelectric means,
3,11...Amplifier, 4,12...Band filter, 6,14...Differential element, 7,15,34,3
6... Rectifier, 8, 16... Multivibrator, 10... Photoelectric element, 13... Amplitude limiter, 1
7, 25, 58... Inverter, 18... AND gate, 19... Integrator, 20... Reset circuit, 21... Delay element, 22... Alarm device, 2
3, 24...threshold detector, 26...phase comparator,
30, 31... comparator, 38, 39... demodulator,
59...Noah Gate, 71...Interference Filter,
74...Sensing element.

Claims (1)

Claims: 1. A first current circuit receiving flickering frequency components of the flame radiation in the wavelength range of at least the resonant radiation of carbon dioxide by means of photoelectric means and a bandpass filter and generating a useful signal for the alarm means. In a flame detection device comprising: a second current circuit with coupling means for eliminating interference radiation generated by the thermal radiator, the second current circuit comprising: a predetermined wavelength passage; a filter 9 having a bandpass and a photoelectric means 1 for receiving radiation having a wavelength above the resonance wavelength region of carbon dioxide and generating a disturbance signal;
0 and another band filter 12 having the same interfering radiation flicker frequency pass band as in said first current circuit for the flame flicker frequency; and a coupling coupling said first and second current circuits. circuit means 18, 26, 59, 17, 25, 58, said coupling circuit means providing an output of the same polarity to said second current circuit, taking into account the statistical distribution of said flame radiation and interference radiation. blocking the transmission of the signals of the first current circuit if the signals appear simultaneously, and blocking the transmission of the signals of the first current circuit if the output signals of the second current circuit are absent or appear with a different polarity.
flame detection device, characterized in that it is configured to generate an output signal in such a way that the signal of the current circuit is transmitted to the alarm means 22. 2. a filter 1 in which said first current circuit has a passband comprising a resonant radiation at 4.4 μm for the infrared radiation of the flame; and photoelectric means 2 for receiving the infrared radiation and generating a corresponding useful electrical signal; an amplifier 3 for amplifying the useful electrical signal of said photoelectric means 2; a bandpass filter 4 with a passband for the flickering frequency of the flame; converting and differentiating the amplified output signal of said bandpass filter and converting the same pulse a signal converter 5, 6, 7, 8 for generating an effective rectangular pulse 50 of width and amplitude, while said second current circuit has a 6 μm range of interference radiation.
a filter 9 with a larger wavelength (λ) passband; further optoelectronic means 10 for receiving said jamming radiation and generating a corresponding jamming electrical signal; and another amplifier for amplifying said jamming electrical signal. 11 and another bandpass filter 12 having a passband for the same flickering frequency of the interfering radiation as for the flickering frequency of the flame in said first current circuit, converting the amplified output signal of said further bandpass filter;
another signal converter 13, 14, which differentiates and generates a disturbance pulse 51 of the same pulse width and amplitude;
15, 16, said coupling circuit means 18 is constructed as an AND gate, receives said effective rectangular pulse 50 at its first input terminal, and receives said effective rectangular pulse 50 at its second input terminal. 17. A flame detection device according to claim 1, wherein the flame detection device is adapted to receive an inverted disturbing rectangular pulse 52 of the same pulse width and amplitude. 3. The first current circuit is resistant to infrared radiation of the flame.
a filter 1 having a passband containing the resonant radiation at 4.4 μm; photoelectric means 2 for receiving said infrared radiation and generating a corresponding useful electrical signal; and an amplifier 3 for amplifying the useful electrical signal from said photoelectric means. , a bandpass filter 4 with a passband for the flickering frequency of the flame, and an effective rectangular pulse 41 with a constant amplitude and a pulse width depending on the period of the individual oscillations 40 of the effective signal representing the flickering frequency of the flame. the second current circuit has a signal converter 30, 32 that generates a signal converter 30, 32, and the second current circuit
a further filter 9 with a passband of a larger wavelength (λ); further optoelectronic means 10 for receiving said disturbing radiation and generating a corresponding electrical signal; another amplifier 11 for amplifying and another bandpass filter 12 having a passband for the flickering frequency of the disturbing radiation which is the same as that of the flame in the first current circuit, representing the flickering frequency of the disturbing radiation; and a further signal converter 31, 33, which generates a jamming rectangular pulse 43 with a constant amplitude and a pulse width depending on the period of each individual oscillation 40 of the jamming signal, said coupling being configured as an AND gate. The circuit means 18 receives at its first input said effective rectangular pulse 41 and at its second input receives, via an inverter 17, an inverted disturbing rectangular pulse 44 with different pulse widths and constant amplitude. A flame detection device according to claim 1, adapted to receive a flame detection device. 4. Said first current circuit comprises a filter 1 having a wavelength passband for infrared radiation of the flame, including resonant radiation at 4.4 μm, and photoelectric means 2 for receiving said infrared radiation and generating a corresponding useful electrical signal. , an amplifier 3 for amplifying the effective electrical signal of the photoelectric means 2, a bandpass filter 4 having a passband for the flame flickering frequency, and an envelope curve 46 enveloping the oscillations 45 of the flame flickering frequency.
a signal converter 38,3 which generates an effective rectangular pulse 47 with a pulse width and constant amplitude depending on
0,7, said second current circuit having a further filter 9 having a wavelength (λ) passband greater than 6 μm of the disturbing radiation, and another filter 9 for receiving the disturbing radiation and generating a corresponding electrical signal. a further amplifier 11 for amplifying the interfering electrical signal from said further optoelectronic means 10 and a passage for a flicker frequency of the interfering radiation which is the same as that of said flame in said first current circuit. a further bandpass filter 12 with a band and a further signal converter 39, 31 generating a jamming rectangular pulse 48 with a constant amplitude and a pulse width that depends on an envelope curve 46 enveloping the flickering frequency oscillations 45 of said jamming radiation; ，
15, said coupling circuit means 18, configured as an AND gate, receives at its first input a valid rectangular pulse 47, and at its second input receives different pulses via an inverter 17. Flame detection device according to claim 1, adapted to receive an inverted disturbing rectangular pulse 49 having a pulse width and constant amplitude. 5. Said first current circuit comprises a filter 1 having a wavelength pass band for the infrared radiation of the flame, a photoelectric means 2 for receiving the infrared radiation and generating a corresponding useful electrical signal, and a useful electrical signal from said photoelectric means 2. an amplifier 3 for amplifying the flame, a band filter 4 having a pass band for the flickering frequency of the flame, and an electric vibration 60 representing the flickering frequency of the flame received from the band filter 4, and when a predetermined threshold value is exceeded; a threshold detector 23 for generating a useful output signal 61 for the interference radiation, while the second current circuit has a further filter 9 with a wavelength (λ) passband greater than 6 μm for the interference radiation; further photoelectric means 10 for receiving and generating a corresponding electrical signal;
a further amplifier 11 for amplifying the disturbing electrical signal from said further photoelectric means 10 and another having a passband for the flickering frequency of the disturbing radiation which is the same as that of said flame in said first current circuit; a bandpass filter 12 and another threshold detector 2 for receiving electrical oscillations representative of the flicker frequency of the jamming radiation from the further bandpass filter and generating a jamming output signal 62 if a predetermined threshold is exceeded.
4 and configured as a phase comparator, the coupling circuit means 26 receives at its first input the valid output signal 61 of the threshold detector and at its second input receives an inverter 25. 2. A flame detection device according to claim 1, adapted to receive an inverted disturbance output signal 63 from said further threshold detector 24 via a . 6. The coupling circuit means 18 is configured as a NOR circuit 59, and the inverter 5 is connected to the first input thereof.
8. The flame detection device according to claim 1, comprising: 8. 7. The coupling circuit means 18 is followed by an integrating element 19 which accumulates the valid output signal of the coupling circuit means and which resets the reset circuit 2.
0, and the reset circuit includes an integrating element 1.
7. A flame detection device according to any one of claims 1 to 6, wherein the accumulated contents of 9 are reset, thereby avoiding generation of false alarms due to discrete undesired pulses. 8. said integrating element 19 includes a counter for counting the output signal of said coupling circuit means 18, and said reset circuit 20 periodically controls said counter;
The flame detection device according to claim 7, further comprising means for resetting when there is no output signal within a predetermined time. 9. The integrating element 19 includes a capacitor for summing the output signals of the coupling circuit means 18, and the reset circuit 20 includes means for discharging the capacitor with a larger discharging time constant than when charging the capacitor with the output signal. A flame detection device according to claim 8. 10 Following the integrating element 19, a threshold switch circuit is provided, which outputs an output signal to the alarm generator 22 when the summed valid signal of the integrating element 19 exceeds a predetermined threshold value. A flame detection device according to any one of claims 7 to 9, adapted to generate a flame detection device. 11 A delay element 21 is provided between the threshold switch circuit and the alarm generator 22, and the delay element 21 temporally delays the output signal of the threshold switch circuit and supplies it to the alarm generator 22. A flame detection device according to claim 10. 12 at least two current circuits 1 of the first type,
2, 3, 4, 5, 6, 7, 8; 30, 32; 3
8, 23 is the optical wavelength range of flame λ = 4 to 4.8
μm, 3 to 3.8 μm, 1.8 to 2.8 μm, 0.7
to 1.2 μm, or 0.1 to 0.5 μm, and a second type of current circuit 9, 10, 11, 12, 1
3, 14, 15, 16; 31, 33; 39; 2
4, 25 generate a disturbance electrical signal corresponding to an optical wavelength range (λ) greater than 6 μm of the disturbance source, and said two current circuits are connected to logic coupling circuit means 18, 2.
6, 59, 17, 25, and 58. The flame detection device according to any one of claims 1 to 11. 13. Claims 2 to 4, wherein the filter 1 of the first current circuit is composed of a quartz layer 72, a semiconductor layer 70, and a broadband interference filter 71 having a wavelength range λ of 4.0 to 4.8 μm. 12
The flame detection device according to any of paragraphs. 14 The filter 1 of the first current circuit includes a quartz layer 72, a germanium layer 70, and a wavelength range λ=
The flame detection device according to any one of claims 2 to 12, comprising a broadband interference filter 71 of 4.0 to 4.8 μm. 15. Any one of claims 1 to 14, wherein the first optoelectronic means 2 are formed from a material selected from the group of lithium-tantalate (LiTaO ₄ ) and lead-selenide (PbSe). The flame detection device described in . 16. Flame detection device according to any one of claims 1 to 15, wherein the second photoelectric means 10 is formed from lithium tantalate (LiTaO ₄ ).