JPH0449482Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to an ignition detection device for detecting ignition of a pilot burner and a main burner in an industrial furnace or the like. [Prior Art] Conventionally, as the above-mentioned ignition detection device, a so-called optical type device as shown in FIG. 8, for example, has been generally used. In the same figure, 1
01 main burner, this main burner 1
An ultravision 102 is provided near 01. This ultravision 102 detects ultraviolet rays, infrared rays, visible light, etc. emitted from the flame of the main burner 101, and the energy level detected by this ultravision 102 is a preset value. If it is higher than , an "ignition" signal is output. In addition to such optical devices, there are micro-pressure detection devices that do not directly detect ignition or extinguishment, but detect minute pressure vibrations that occur during combustion, and determine the combustion state of the burner from the vibration pattern. Devices have already been proposed (for example, in Japanese Patent Application Laid-Open No. 1983-
(See Publication No. 18017). This device utilizes the characteristics of gas vibrations generated by combustion, that is, relatively high frequency components appear prominently during rapid combustion, and relatively low frequency components appear prominently during slow combustion. The device is configured to perform state detection. [Problems to be solved by the invention] First, the above-mentioned optical device has the following problems. (1) Flame detectors such as the UltraVision 102 may be used in situations where the visibility is obstructed by the above or atomized oil, etc.
There is a risk of malfunction due to the influence of (2) Since the flame must be detected directly and visually, there are restrictions on the installation location of a flame detector such as the ultravision 102 described above. (3) If the luminescence intensity is low, such as when low-calorie fuel is used, malfunctions are likely to occur and detection conditions are likely to be restricted. (4) When attempting to detect the ignition of other burners such as a pilot burner in addition to the main burner 101, it is not possible to distinguish between the flames of the two. On the other hand, if the device that detects the combustion state from minute pressure vibrations as described above is used as it is as an ignition detection device, the above problems can be solved. However, this low-pressure type device captures vibration detection signals generated by combustion over a wide range and determines whether the combustion status is good or bad, so one sensor is required to detect one combustion. is required. That is, this device requires as many sensors as the number of burners, and if it is used only for the purpose of ignition detection, it will be costly. In view of these circumstances, it is an object of the present invention to provide an ignition detection device that can appropriately detect ignition and extinguishment of a pilot burner and a main burner with a low-cost structure. [Means for Solving the Problems] The present invention is an ignition detection device that detects ignition of a pilot burner and a main burner, and includes a detection device that is provided in common to both burners and that detects minute pressure vibrations accompanying combustion. means for extracting components within a preset frequency band for the pilot burner flame and the main burner flame from the single detection signal and converting the extracted signals into effective values; The apparatus is equipped with a determination means for determining whether each burner is ignited or extinguished by comparing a preset setting value for each burner and outputting a signal. Further, the determination means outputs an ignition signal when ignition of at least one of the pilot burner and the main burner is recognized, and outputs an extinguishing signal when ignition of both is not recognized. There is. [Operation] According to the above configuration, only the components within the frequency band corresponding to each burner are individually extracted from a single detection signal related to minute pressure vibrations detected by the detection means, and each of the extracted components is individually extracted. It is determined whether each burner should be ignited or extinguished based on the signal level. [Embodiment] FIG. 1 shows an ignition detection device according to a first embodiment of the present invention. In the figure, 11 is a combustion furnace, and within this combustion furnace 11 a main burner 9 and a pilot burner 9' are arranged. A probe 8 is provided on the side wall of the combustion furnace 11 and faces inside and outside, and a microphone (detection means) 1 connected to the main body 12 of the apparatus is attached to the tip of the probe 8. As this microphone 1, the capacitor type microphone shown in the figure or the dynamic type microphone can be used. In the case of the dynamic type, although the detection level in the low frequency range is lowered, it has the advantage of omitting the applied voltage for the power supply. . The device main body 12 includes an amplifier 2, a bandpass filter (extraction means) 3, 3', an amplifier (extraction means) 4,
4', an effective value converter (extraction means) 5, 5', a comparator (judgment means) 6, 6', and alarm output terminals 7a to 7c, 7a' to 7c', and an external monitor edge. Lamps 13, 13', red lamp 14,
14', and the power supply circuit 15. The band pass filters 3 and 3' are connected to the amplifier 2 in parallel with each other, and among the detection signals inputted from these amplifiers 2, the combustion of each burner 9 and 9' is detected as described below. Only components belonging to a characteristic and unique frequency band are passed. The effective value converters 5, 5' are taken out by the bandpass filters 3, 3', respectively,
The signals amplified by the amplifiers 4 and 4' are converted into effective values, and then averaged. The comparison setters 6, 6' are the effective value converters 5, 6',
5', and each burner 9,
9' are individually compared with preset values, and if the former exceeds the latter, an "ignition" signal is output, and in the opposite case, an "extinguishing" signal is output. . Alarm output terminals 7a and 7a' are ground terminals,
The alarm output terminals 7b, 7b' are connected to the comparison setting device 6,
6' outputs a "extinguishing" signal, the edge lamps 13, 13' as well as the alarm output terminals 7a,
7a' and the power supply circuit 15. On the other hand, the alarm output terminals 7c and 7c' are
When the comparison setting devices 6, 6' output an "ignition" signal, the red lamps 14, 14', the alarm output terminals 7a, 7a' and the power supply circuit 15
connected to. The frequency band to be passed by the bandpass filters 3 and 3' is a second frequency band determined in advance through experiments.
It is set based on the combustion characteristics of the main burner 9 and pilot burner 9' as shown in FIGS. These FIGS. 2 to 5 show vibration waveforms and power spectra under the conditions shown in the following table.

[Effect of idea]

As described above, the present invention extracts only the components within a preset frequency band for each burner's flame from a single detection signal related to minute pressure vibrations, converts them into effective values, and converts these extracted signals and By comparing the preset values for each burner, it is determined whether each burner is lit or extinguished, and a signal is output.The ignition or extinguishment of both burners can be detected by a single detection means. Proper ignition of each burner, with a low-cost construction that allows
It has the effect of being able to determine whether a fire has been extinguished. Further, if ignition of at least one of the pilot burner and the main burner is detected, an ignition signal is output, and if ignition of both is not detected, an extinguishing signal is output.
Further, it is possible to determine whether to ignite or extinguish both burners with virtually no inconvenience while reducing costs.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the ignition detection device according to the first embodiment of the present invention, and FIGS. 2a and 2b are graphs showing vibration waveforms and power spectra when the main burner and pilot burner are in the extinguished state.
Figures 3 a and b are graphs showing the vibration waveform and power spectrum when only the pilot burner is ignited, Figures 4 a and b are graphs showing the vibration waveform and power spectrum when only the main burner is ignited, and Figure 5 is a graph showing the vibration waveform and power spectrum when only the main burner is ignited. Figures a and b are graphs showing vibration waveforms and power spectra when the main burner and pilot burner are ignited, Figure 6 is an overall configuration diagram of the ignition detection device in the second embodiment, and Figure 7 is the diagram in the third embodiment. FIG. 8 is a circuit diagram showing the main parts of the ignition detection device, and FIG. 8 is a side view showing the main parts of the conventional optical ignition detection device. 1... Microphone (detection means), 3, 3'...
Bandpass filter (extraction means), 4, 4'... Amplifier (extraction means), 5, 5'... Effective value converter (extraction means), 6, 6'... Comparison setting device (comparison means),
9...Main burner, 9'...Pilot burner,
10...Main frame, 10'...Pilot frame, 12...Device main body, 16...Discriminator (determination means), 17...Strain gauge (detection means).

Claims (1)

[Scope of Claim for Utility Model Registration] 1. An ignition detection device for detecting ignition of a pilot burner and a main burner, which is provided in common with both burners and includes a detection means for detecting minute pressure vibrations accompanying their combustion; extraction means for extracting components within a preset frequency band for the pilot burner flame and the main burner flame from a single detection signal and converting them into effective values; 1. An ignition detection device comprising: determination means for determining whether each burner is ignited or extinguished by comparing the set value for each burner and outputting a signal. 2. The determining means outputs an ignition signal when ignition of at least one of the pilot burner and the main burner is recognized, and outputs an extinguishing signal when ignition of both is not recognized. The ignition detection device according to claim 1.