Automatic cleaning system for optical window of laser oxygen content online analyzer

Abstract

The utility model belongs to the technical field of analytical instruments, and relates to an automatic cleaning system for an optical window of a laser oxygen content online analyzer, which is characterized by comprising a laser oxygen content measuring system, a reference signal detecting system and a purging system. According to the utility model, measuring range concentration oxygen measurement of the analyzer sealed in the reference gas chamber is used as a basis for judging whether the optical window of the analyzer is polluted or not, so that the cleaning function of the optical window of the analyzer is automatically realized, and the defects of long treatment time, inconvenience in operation and certain dangerousness caused by manual cleaning are overcome; the maintenance amount of the analyzer is greatly reduced, and the measurement precision of the analyzer is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of analytical instruments, and in particular is an automatic cleaning system for an optical window of an online laser oxygen content analyzer. Background Art

[0002] In the chemical industry, the detection of oxygen content in various combustion furnaces is very important.

[0003] Traditional oxygen measurement instruments use the lead-out measurement method, which has the disadvantages of easy corrosion and clogging of the sampling pipeline, external air leakage affecting the measurement accuracy, and long response time. It cannot complete the oxygen measurement in the combustion furnace in a timely and accurate manner.

[0004] The oxygen content is measured through tunable laser spectroscopy technology. The analyzer is installed in situ on the combustion furnace body. It has the advantages of strong adaptability, fast response speed and high accuracy, and is widely used in various chemical combustion furnaces.

[0005] However, the complex process gas components in chemical combustion furnaces can easily cause dust and water vapor to contaminate the optical window of the laser analyzer, affecting laser transmission and further affecting measurement accuracy.

[0006] The high temperature and high corrosion process background brings great safety risks to the manual cleaning of the analyzer's optical window and may even affect the normal operation of the device.

[0007] It is particularly necessary to develop a self-cleaning system that can automatically determine the contamination of the optical window of the laser analyzer and then automatically purge it. Summary of the invention

[0008] The purpose of the present invention is to provide an automatic cleaning system for the optical window of a laser oxygen content online analyzer.

[0009] The technical solution to the problem of the present invention is: an automatic cleaning system for the optical window of a laser oxygen content online analyzer, which is characterized in that it includes a laser oxygen content measurement system, a reference signal detection system and a purge system; the laser oxygen content measurement system includes a laser light source, a spectrometer, a measurement window, a photoelectric sensor and a measurement signal converter; the reference signal detection system includes a reference gas chamber, a reference window, a photoelectric sensor and a reference signal converter; the purge system includes a purge gas source, a purge pipeline, a purge nozzle and a computer control unit; the laser light source is respectively connected to the process equipment and the reference gas chamber through the spectrometer, the measurement signal converter and the reference signal converter are connected to the computer control unit, and the purge nozzle is connected to the measurement window.

[0010] Generally, the spectrometer is connected to the process equipment via a stainless steel short section, and a measuring window is arranged on the outer side of the stainless steel short section. Preferably, the spectrometer comprises two stainless steel short sections, and two measuring windows are arranged on the outer side.

[0011] The spectrometer is connected to the reference gas chamber via a stainless steel short section, and a reference window is arranged on the outer side of the stainless steel short section. Preferably, the spectrometer comprises two stainless steel short sections, and two reference windows are arranged on the outer side.

[0012] The laser light source has an oxygen characteristic spectrum which is absorbed only by oxygen.

[0013] The quartz material is used for coupling the laser and the measuring window of the measured oxygen. The laser signal absorbed by the oxygen in the process equipment is converted into an electrical signal by a photoelectric sensor and then converted into a digital signal by a measuring signal converter.

[0014] The reference gas chamber of the sealed analyzer range concentration oxygen converts the laser signal absorbed by the oxygen in the reference gas chamber into an electrical signal through a photoelectric sensor and then into a digital signal through a signal converter.

[0015] The purge gas source is a nitrogen gas source, and the nitrogen gas source, the purge pipeline and the purge nozzle are connected through a purge control valve, and the purge nozzle is aligned with the center position of the laser light path in the measurement window.

[0016] The computer control unit controls the purge system by receiving the oxygen measurement signal and the reference signal.

[0017] The present invention is aimed at the automatic cleaning system of the optical window of the laser oxygen content online analyzer, and designs an automatic cleaning system including a laser oxygen content measurement system, a reference signal detection system, and a purge system. The automatic cleaning system splits the characteristic spectrum emitted by the laser light source, which is only absorbed by oxygen, and passes it through the oxygen content measurement system and the reference signal detection system respectively. The laser passing through the oxygen content measurement system is absorbed and attenuated by the oxygen in the process equipment, and the attenuated laser converts the light intensity signal into an electrical signal V through a photoelectric sensor and a measurement signal converter. 测量 The reference signal detection system is designed with a reference gas chamber sealed with a fixed concentration of oxygen (analyzer range concentration). The other laser beam after the split passes through the reference gas chamber and is absorbed and attenuated by the oxygen sealed in the reference gas chamber. The attenuated laser converts the light intensity signal into an electrical signal V through the reference photoelectric sensor and the reference signal converter. 参比 During the analyzer measurement, the measurement signal V 测量 On the one hand, it is related to the oxygen concentration. As the oxygen content increases, the absorption degree of the characteristic spectrum increases. 测量 The signal becomes smaller, but under stable process conditions, the measured oxygen content is basically stable near the design value, and the measurement signal V 测量 On the other hand, as the analyzer runs longer, the dust and water vapor in the process gas continue to pollute the measurement window, affecting the transmission of the laser and causing the measurement signal V 测量 When the measured signal V 测量When the oxygen concentration drops to a certain level and the analyzer cannot measure normally, the measuring window needs to be cleaned. The reference gas chamber with a sealed fixed concentration of oxygen (analyzer range concentration or process oxygen content design concentration) does not come into contact with the process gas and will not be contaminated by dust and water vapor in the process gas components. The detected reference signal V 参比 Relatively unchanged. Under the control of the computer control unit, by comparing the measurement signal V 测量 and reference signal V 参比 The mathematical relationship between the two can be used to determine whether the optical window of the analyzer is contaminated. 测量 Less than K (adjustable parameter set by the analyzer, set by software according to specific process systems) * reference signal V 参比 When the measurement signal V 测量 Greater than K (adjustable parameter set by the analyzer, set by software according to specific process systems) * reference signal V 参比 When the computer control unit determines that the optical window is not contaminated, the nitrogen purge system is turned off and the purge is stopped.

[0018] The present invention uses the measurement of the analyzer range concentration oxygen sealed in the reference gas chamber as the basis for judging whether the optical window of the analyzer is contaminated, and automatically realizes the cleaning function of the optical window of the analyzer, thereby avoiding the defects of long processing time, inconvenient operation and certain danger caused by manual cleaning, greatly reducing the maintenance amount of the analyzer and improving the measurement accuracy of the analyzer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of oxygen measurement system components in an embodiment of the present invention.

[0020] In the figure: 1: laser light source; 2: spectrometer; 3: measurement window 1; 4: process equipment; 5: measurement window 2; 6: photoelectric sensor 1; 7: measurement signal converter; 8: equipment short circuit 1; 9: equipment short circuit 2;

[0021] Figure 2 Schematic diagram of the reference signal detection system components in an embodiment of the present invention.

[0022] In the figure: 10: reference gas chamber; 11: reference window 1; 12: reference short circuit 1; 13: air inlet; 14: air outlet; 15: reference short circuit 2; 16: reference window 2; 17: photoelectric sensor 2; 18: reference signal converter;

[0023] Figure 3 Schematic diagram of a nitrogen purge system in an embodiment of the present invention.

[0024] In the figure: 19: gas source; 20: purge pipeline; 21: purge control valve; 22: purge nozzle 1; 23: purge nozzle 2; 24: computer control unit; DETAILED DESCRIPTION

[0025] The present invention is further described below with reference to the accompanying drawings and examples. Example

[0026] An automatic cleaning system for the optical window of the laser oxygen content online analyzer Figure 1-3 , mainly including laser oxygen measurement system, reference signal detection system and purge system.

[0027] Reference Figure 1 The laser oxygen content measurement system comprises a laser light source (1), a spectrometer (2), a measurement window, a photoelectric sensor 1 (6) and a measurement signal converter (7).

[0028] Reference Figure 2 The reference signal detection system includes a reference gas chamber (10), a reference window, a photoelectric sensor 2 (17) and a reference signal converter (18).

[0029] Reference Figure 3 The purge system includes a purge gas source (19), a purge pipeline (20), a purge nozzle and a computer control unit (24).

[0030] In the embodiment, the laser light source (1) is respectively connected to the process equipment (4) and the reference gas chamber (10) via the beam splitter (2), the measurement signal converter (7) and the reference signal converter (18) are connected to the computer control unit (24), and the purge nozzle is connected to the measurement window.

[0031] In the embodiment, the spectrometer (2) is connected to the process equipment (4) via a stainless steel equipment short section, and comprises two stainless steel equipment short sections, with two measuring windows provided on the outside. The measuring windows are made of quartz material and are used for coupling laser and measured oxygen.

[0032] In the embodiment, the spectrometer (2) is connected to the reference gas chamber (10) via a stainless steel reference nipple, comprising two stainless steel reference nipples with two reference windows provided on the outer sides. The reference gas chamber (10) is a reference gas chamber sealed with a fixed concentration of oxygen (analyzer range concentration).

[0033] Figure 1In the example shown, equipment short circuit 1 (8) and equipment short circuit 2 (9) are welded on both sides of the process equipment where the laser oxygen content online analyzer is installed. The measuring window 1 (3) and the measuring window 2 (5) are sealed and installed on the outside of the equipment short circuit 1 (8) and the equipment short circuit 2 (9), respectively. After the laser light source (1) emits a characteristic spectrum laser that is only absorbed by oxygen and passes through the spectrometer (2), a laser beam passes through the measuring window 1 (3) and is absorbed by the oxygen in the process equipment (4). The absorbed oxygen characteristic spectrum passes through the measuring window 2 (5) and is received by the photoelectric sensor 1 (6) and transmitted into an electrical signal, which is amplified and converted into a digital signal by the measuring signal converter (7).

[0034] Figure 2 In the example shown: reference short circuit 1 (12) and reference short circuit 2 (15) are welded on both sides of the reference gas chamber (10). Reference window 1 (11) and reference window 2 (16) are sealed and installed on both sides of reference short circuit 1 (12) and reference short circuit 2 (15). After the laser light source (1) emits the characteristic spectrum of oxygen through the spectrometer (2), another laser beam

[0035] The light passes through the reference gas chamber (10) and is absorbed by the fixed concentration oxygen sealed in the reference gas chamber (10). The characteristic spectrum of the absorbed oxygen is received by the photoelectric sensor 2 (17) and converted into an electrical signal, which is amplified and converted into a digital signal by the reference signal converter (18).

[0036] Figure 3 In the example shown: the computer control unit (24) receives the reference signal transmitted by the measurement signal converter (7) and the reference signal converter (18), and compares the data relationship between the two to determine the degree of contamination of the optical window. When the measurement signal Vmeasured is less than K (an adjustable parameter set by the analyzer, set by software according to the specific process system) * reference signal Vreference, the computer control system determines that the contamination of the optical window has reached the degree that needs to be cleaned, opens the nitrogen purge control valve (21), and passes the nitrogen in the nitrogen source (19) through the nitrogen purge pipeline (20) through the purge nozzle 1 (22) and the purge nozzle 2 (23). The purge nozzle 1 (22) and the purge nozzle 2 (23) are respectively aligned with the center position of the laser light path in the measurement window 1 (3) and the measurement window 2 (5), and the optical window of the analyzer is purged to achieve the purpose of cleaning. On the contrary, the computer control system determines that the degree of contamination of the optical window is not necessary, and closes the nitrogen purge control valve. The computer control unit cyclically executes the above process to achieve the purpose of automatic cleaning of the analyzer.

Claims

1. An automatic cleaning system for the optical window of a laser oxygen content online analyzer, characterized in that it includes a laser oxygen content measurement system, a reference signal detection system and a purge system; the laser oxygen content measurement system includes a laser light source, a spectrometer, a measurement window, a photoelectric sensor and a measurement signal converter; the reference signal detection system includes a reference gas chamber, a reference window, a photoelectric sensor and a reference signal converter; the purge system includes a purge gas source, a purge pipeline, a purge nozzle and a computer control unit; the laser light source is connected to the process equipment and the reference gas chamber respectively through the spectrometer, the measurement signal converter and the reference signal converter are connected to the computer control unit, and the purge nozzle is connected to the measurement window.

2. The automatic cleaning system according to claim 1, characterized in that The spectrometer is connected to the process equipment through a stainless steel short section, and a measuring window is arranged on the outer side of the stainless steel short section.

3. The automatic cleaning system according to claim 2, characterized in that It consists of two stainless steel nipples with two measuring windows on the outside.

4. The automatic cleaning system according to claim 1, characterized in that The spectrometer is connected to the reference gas chamber through a stainless steel short section, and a reference window is arranged on the outer side of the stainless steel short section.

5. The automatic cleaning system according to claim 4, characterized in that It consists of two stainless steel nipples with two reference windows on the outside.

6. The automatic cleaning system according to claim 1, characterized in that The laser light source has an oxygen characteristic spectrum which is absorbed only by oxygen.

7. The automatic cleaning system according to claim 1, characterized in that The quartz material is used to couple the laser and the measuring window of the measured oxygen. The laser signal absorbed by the oxygen in the process equipment is converted into an electrical signal through a photoelectric sensor and then converted into a digital signal by a measuring signal converter.

8. The automatic cleaning system according to claim 1, characterized in that The reference gas chamber of the oxygen in the measuring range concentration of the sealed analyzer converts the laser signal absorbed by the oxygen in the reference gas chamber into an electrical signal through a photoelectric sensor and then into a digital signal through a reference signal converter.

9. The automatic cleaning system according to claim 1, characterized in that The purge gas source is a nitrogen gas source, which is connected to the nitrogen gas source, the purge pipeline and the purge nozzle through a purge control valve, and the purge nozzle is aligned with the center position of the laser light path in the measurement window.

10. The automatic cleaning system according to claim 1, characterized in that The computer control unit controls the purge system by receiving the oxygen measurement signal and the reference signal.

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