JPS5965230A - Flame air ratio detecting device - Google Patents

Abstract

PURPOSE:To detect an air ratio quickly and accurately, by dividing the spectrum in the vicinity of the peak wavelength of light emitted from a flame, obtaining the intensity of the light rays, and obtaining the air ratio from the intensity ratio between the two different peaks. CONSTITUTION:Light emitted from a preliminarily mixed flame 1 passes through an objective lens 2 and a slit 3. The light is sequentially transmitted through windows A-C of a rotary disk 4 and inputted to a light detecting element 6. The window A can pass the light having all wavelengths. The windows B and C have interference filters, which transmit the light rays, whose peak wavelengths are in the vicinities of (3100Angstrom ) for an OH group and (5165Angstrom ) for C2 group. The detected signals are inputted to an operation circuit 8, and the detected signal intensity ratio I1/I2 between the OH group and the C2 group is computed. An air ratio is computed by a computing circuit 9 based on the computed value from the circuit 8, and the result is displayed on a display device 10. Thus the air ratio is detected quickly and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention improves the air ratio of a flame such as a premixed flame (supplied air 5 volume/
The present invention relates to a device for detecting air particles (theoretical air particles).

It is a well-known fact that the combustion characteristics of a premixed flame are determined by the air ratio, and rapid and accurate detection of this air ratio has a great influence on combustion control.

By the way, it is well known that the light emitted from the flame of ordinary hydrocarbon fuel has a spectral distribution as shown in Figure 1.
It can be seen that light emission from radicals such as 165^) and CH (λ=4315A) is remarkable. Then, the light intensity from these radicals11. It can also be investigated that Iz and Is have a multivalued function type relationship with the air ratio as shown in FIG. 2(a).

The present invention has been made in view of the above, and the intensity is determined by spectroscopy near the peak wavelength of the light emitted from the flame, and the ratio of the two different intensities to the air ratio is shown in Figure 2 (C). The air ratio is determined from the intensity ratio by paying attention to the fact that it has a substantially -transfer type as shown in FIG.

An embodiment of the present invention is shown in FIGS. 3(a) and 3(b) below.

The explanation will be based on (e).

In the figure, 1 is a premixed flame, 2 is an objective lens, 3 is a slit, and 4 is a rotating circle with an optical interference filter as a light selection means for separating the light from the flame that has passed through the slit 3 in the vicinity of the peak wavelength. The area near the peak wavelength (5165A) of windows B and C2 is installed with an optical interference filter that allows light of all wavelengths to pass through the plate at equal intervals in the circumferential direction and allows the area near the peak wavelength (3100^) of window A10H to pass through. It has a window C equipped with an optical interference filter that allows the light to pass therethrough. 5
The rotating plate 4 is rotated to sequentially open the windows A.

Electric motor that positions B and C in slit 3, 6 is window A,
A photodetection element that converts the light passing through B and C into electrical energy with an intensity corresponding to the intensity of the light; T houses an objective lens 2, a slit 3, a rotating disk 4, an electric motor 5, a photodetection element 6, etc. The main body case 8 starts operating upon receiving the signal intensity Io from the photodetector element 6 corresponding to the light that has passed through the window A, and after a predetermined time, it sequentially detects the signal intensity 11 corresponding to the light that has completely passed through the window B and the window Cfc. Signal strength adjustment 2 and 11 according to the passed light
It is an arithmetic circuit that performs the calculation η: of /I2, and functions together with the front light detection element 6 as a light intensity/summer detection means and an intensity ratio calculation means. Reference numeral 9 denotes a calculation circuit that calculates the air ratio μ according to the value of 1/I2 from the output of the arithmetic circuit 8, and acts as an air ratio determination means. A display device 10 displays the value of the air ratio μ calculated in response to the signal from the calculation circuit 9.

In the air ratio detection device having such a configuration, when the main body case 7 is positioned in front of the premix flame 1 and an operation switch (not shown) is operated, the electric motor 5 starts operating and the rotating disk 4 rotates. When the slit 3 and the window A of the rotary disk 4 match, the signal intensity Io is input to the arithmetic circuit 8 via the photodetector element 6, and the arithmetic circuit 8 starts operating. Arithmetic circuit 8 is window B
, C in order to receive the signal strength 11 of OH and the signal strength 2 of C2, and calculate their strength ratio It/I2. 3
The 1 output circuit 9 receives this calculated value and calculates the air ratio μ accordingly.
k7J- and outputs it to the display device 1o, so the display device 10 quickly displays this value. Then, when the slit 3 and the window A match again, the arithmetic circuit 8 is reset, the air ratio μ is calculated in the same way as above, and a new value is displayed on the display device 10, so that the air ratio μ can be constantly monitored.

In addition, since the light intensity is determined through one photodetection element 6, the intensity ratio is not affected by changes in the photodetection element 6 over time or adhesion of dust etc. to the light receiving surface, which improves the detection accuracy. It will not cause any deterioration.

In this example, the object for calculating the intensity ratio is OH"
The reason for this is OH”.
This is because the inventors confirmed that the intensity ratio of t and C2'' remains almost constant regardless of fluctuations in combustion conditions such as combustion amount and burner wall temperature, and found that high detection accuracy can be obtained. Yes, if you can tolerate a slight decrease in detection accuracy,
A combination of OH" and CH" or IHA02"' and CH may also be used.

FIGS. 4(a), (b), and (e) show another embodiment, which is a further improvement of the above embodiment to improve the detection accuracy. That is, on the rotating disk 4,
All wavelengths of light can pass through.Beak wavelength of window A, OH" (3
Window B is equipped with an optical interference filter that allows the 100X) vicinity to pass through, and window B' is equipped with a 2950X optical interference filter that allows the detection of a continuous spectrum in the vicinity of 3100 people.

Windows C1 and 5 are equipped with optical interference filters that allow the vicinity of the peak wavelength (51655,) of c 2+ to pass through.
530 to detect continuous spectra in the vicinity of 165 people
Windows C' to which 0X optical interference filters are attached are provided at equal intervals in the circumferential direction. Then, the peak wavelength (3100
The signal intensity factor l'' of the continuous spectrum obtained through the nearby window A' is subtracted to obtain the net signal intensity factor lII/, and the peak wavelength (5165 'A) Subtract the signal strength of the continuous spectrum obtained through the nearby window B' to obtain the net intensity I2"'c, intensity ratio Ir'
'/I z'''fn and outputs this to the calculation circuit 9. In other embodiments, even if yellow flame is present or light from an object other than flame is incident on the measuring section, a continuous spectrum can be obtained. Since it subtracts , it also has the advantage of being able to accurately detect the air ratio μ.

As explained above, according to the present invention, the intensity of the light emitted from the flame is determined by spectroscopy in the vicinity of the peak wavelength.
The configuration calculates the intensity ratio near the two peak wavelengths and detects the air ratio according to this value, so the air ratio can be quickly and accurately determined and combustion control performance can be improved. .

[Brief explanation of drawings]

Figure 1 is a diagram showing the emission spectrum distribution from a carbon-hydrogen flame, and Figure 2 (a) is a diagram showing the relationship between the emission intensities Ix, Iz, Ia of OH', Cz", CM" and the air ratio μ. ,
FIG. 2(b) shows the ratio of the above emission intensity, that is, I+ /I2
, I3 /Iz , Is /It and the air ratio μ, FIG. A front view, FIG. 3(c) is an output diagram of the signal intensity output from the same photodetecting element as above, FIG. 4(a) is a track configuration diagram showing another embodiment, and FIG. 4(b) is The front view of the rotating disk same as the above, and FIG. 4(c) is an output diagram of the signal intensity output from the light detection element same as the above. 1... Premixed flame 2... Objective lens 3...
・Slit 4... Rotating disk 5... Electric motor
6... Photodetection element 8... Arithmetic circuit 9...
・Calculation circuit A, A', B, B'... Window agent Shin Kuzuno - (#1 or 1 person) Procedural amendment! ”, (3+2'? Showa year, month, day, '41, Director-General of the License Agency, 1, Indication of the case, Patent Application No. 57-175909, 2, Title of the invention, Flame air ratio detection device 3, Compliance with the case of the person making the amendment. Relationship 91 Intercropping Applicant 6, Contents of Amendment 0) In the second line of page 3 of the specification, the phrase “Figure 2 (C)” has been changed to “
2(b)". (2) In the specification @ page 3, line 16, "rotating plate 4" is corrected to "rotating disc 4." More than 189

Claims (3)

[Claims] (1) a light sorting means such as an optical interference filter that separates light emitted from a flame near its peak wavelength, and a light intensity detection means that detects the intensity of the wavelength portion separated by the light sorting means; an intensity ratio calculation means for calculating an intensity ratio from two different intensities of the output of the light intensity detection means; an air ratio determination means for determining an air ratio based on the intensity ratio from the output of the intensity ratio calculation means; A flame air ratio detection device characterized by comprising: (2) The optical selection means is OR (3100 people) and C2'' (51 people).
65^) The flame air ratio detection device according to claim 1, characterized in that the light emitted from each radical of 65^) is spectrally analyzed in the vicinity of the peak wavelength. (3) The optical sorting means separates the continuous spectrum in the vicinity of the peak wavelength, and the calculation means calculates the difference between the intensity in the vicinity of the peak wavelength and the intensity of the continuous spectrum to calculate an intensity ratio. A flame air ratio detection device according to claim 1 or 2.