On-line light path centering device for laser oxygen analyzer

Abstract

The utility model belongs to analytical instrument technical field relates to a kind of laser oxygen analyser online light path centering device, including coaxial centering laser emission unit and laser receiving unit being placed in the measurement pipeline both sides;Laser emission unit and laser receiving unit are connected by cable;Laser emission unit includes instrument control system and laser transmitter, and there is centering coarse adjustment mechanism between laser emission unit and measurement pipeline;Laser receiving unit includes glass window, detector assembly, and detector assembly is equipped with centering fine adjustment mechanism.The utility model can carry out light path centering coarse adjustment, and also can realize light path centering fine adjustment, can greatly improve light path adjustment efficiency, realize that light path centering accuracy reaches more than 95%, so that the measurement accuracy of laser gas analyzer is greatly improved.

Description

Technical Field

[0001] This utility model belongs to the field of analytical instrument technology, specifically relating to an online optical path alignment device for a laser oxygen analyzer. Background Technology

[0002] In the chemical industry, the detection of oxygen content in various combustion furnaces is crucial and requires precise measurement using a laser oxygen analyzer, typically a split-type in-situ laser oxygen analyzer. Laser oxygen analyzers require periodic calibration and standardization during use. The current common calibration method involves removing the analyzer from the measuring pipeline and calibrating it on a specific standard pipeline. After calibration, the analyzer is then reinstalled on the pipeline. During the reinstallation process, it is essential to ensure that the optical paths of the laser emitting unit and the receiving unit are accurately coaxially aligned.

[0003] The existing online optical path alignment method can only adjust the four M16 bolts on the transmitter unit mounting flange according to the magnitude of the light intensity signal collected by the receiver unit. The larger the light intensity signal, the better, but it should not be less than 20%. After the adjustment is completed, it is tightened by the M10 hex bolts on the transmitter unit mounting flange.

[0004] The existing laser oxygen analyzer has the following problems in online alignment: (1) When the furnace is not shut down, the gas composition is complex and there may be corrosive or toxic substances, so it is difficult to adjust the alignment by temporarily using external equipment at the flange; (2) The internal structure of the transmitting and receiving units of the existing laser oxygen analyzer is fixed, and the optical path alignment can only be achieved by manually adjusting the bolts of the transmitting unit mounting flange; (3) The existing optical path alignment method selects the light intensity signal as a reference quantity, which cannot guide the rapid adjustment of alignment; (4) The manual adjustment used in the existing optical path alignment method makes it difficult to guarantee the accuracy of the instrument's optical path adjustment.

[0005] The light intensity signal used for manual alignment is rather abstract, making it difficult to determine which bolt to tighten or loosen, resulting in significant adjustment challenges. Furthermore, manual operation makes it difficult to guarantee the accuracy of coaxial alignment of the optical path. Therefore, a high-precision online optical path alignment device for laser oxygen analyzers is needed to solve these problems. Utility Model Content

[0006] The purpose of this invention is to address the above-mentioned problems by providing an online optical path alignment device for a laser oxygen analyzer. This device can significantly improve the efficiency of optical path adjustment and the accuracy of optical path alignment, thereby greatly enhancing the measurement accuracy of the laser gas analyzer.

[0007] The main technical solution of this utility model is as follows: an online optical path alignment device for a laser oxygen analyzer, characterized in that it includes a laser emitting unit and a laser receiving unit coaxially aligned on both sides of a measuring pipe; the laser emitting unit and the laser receiving unit are connected by a cable; the laser emitting unit includes an instrument control system and a laser emitter, and a coarse alignment mechanism is provided between the laser emitting unit and the measuring pipe; the laser receiving unit includes a glass window and a detector assembly, and the detector assembly is equipped with a fine alignment mechanism.

[0008] Furthermore, the laser emitting unit is mounted on one side of the measuring pipeline via an instrument mounting flange, an air inlet valve, and an equipment flange; the centering coarse adjustment mechanism includes an elastic body and bolts placed between the instrument mounting flange and the air inlet valve flange.

[0009] More preferably, the bolts include four M16 balancing bolts and four M10 internal hexagonal retaining bolts; the elastomer is an O-ring.

[0010] Furthermore, the laser receiving unit is installed on the other side of the measuring pipeline via an instrument mounting flange, an exhaust valve, and an equipment flange.

[0011] Furthermore, the centering and fine-tuning mechanism sequentially includes a window cover plate for fixing the glass window, an elastomer, a detector base, and a power unit connected to the support platform lock nut. The window cover plate and the detector base are connected by screws. The power unit is an integral unit, including a stepper motor, a transmission device, and a lead screw mounted on the power base plate. The top of the lead screw is connected to the screw and can drive the screw to rotate.

[0012] More preferably, the transmission device includes a flexible coupling, an angular contact bearing, and a sliding telescopic shaft, etc., to achieve linear motion of the screw by driving the lead screw with a stepper motor.

[0013] More preferably, the viewing window cover is hollow and has an elastic body limiting groove on the back; the screws include 4 hexagonal screws that are adapted to the ball end of 4 lead screws; the elastic body has a certain thickness and can adjust the angle of the detector base by rotating the screws, preferably the elastic body is an O-ring; the detector base is provided with a connection structure for pluggable detector components.

[0014] More preferably, the detector base is hollow and has a groove. The front end of the detector assembly has a locking boss that matches the groove, and the rear end has a limiting boss. The limiting boss and the detector base have corresponding threaded fixing holes. Through this pluggable structure, the locking boss controls the orientation of the detector assembly inserted into the detector base, and the limiting boss controls the depth of insertion. After insertion, the two are fixed together through the threaded fixing holes, ensuring that the detector base and the detector assembly can only be fixed in one position.

[0015] More preferably, the detector assembly includes two replaceable and pluggable detector assemblies with identical appearance and concentricity, divided into a detector optical path adjustment assembly and a detector detection assembly. They can be selected for insertion according to the instrument's operational requirements.

[0016] More preferably, the detector optical path adjustment component includes a PSD displacement sensor, and the detector detection component includes a photodetector.

[0017] The working principle of the online optical path alignment device for a laser oxygen analyzer is as follows: The laser emitting unit and laser receiving unit are reinstalled in the pipeline. The detector detection component inside the laser receiving unit is removed, and the detector optical path adjustment component and power unit are installed and connected to the laser emitting unit via a cable. Power is turned on, and the optical path adjustment interface is accessed. The control system controls the stepper motor to rotate, returning the sliding telescopic shaft in the transmission device to its initial position. The optical path adjustment interface displays the spot position information transmitted by the detector optical path adjustment component (PSD displacement sensor). Clicking the optical path optimization button on the interface causes the control system to calculate the offsets ΔX and ΔY relative to the center origin based on the spot position coordinates. An algorithm generates a pulse control signal to drive the stepper motor to control the lead screw to move forward or backward to achieve linear movement of the screw. By controlling the different strokes of the four screws, the precise angular displacement of the detector component is achieved, realizing fine-tuning of the optical path alignment and ensuring the optical path is collimated to the center. The instrument is then powered off, the power unit and detector optical path adjustment component are removed, and the detector detection component is reinstalled. Power is then restored, and the instrument operates normally.

[0018] The online optical path alignment device for this laser oxygen analyzer allows for coarse optical path alignment via bolts on the instrument mounting flange. Simultaneously, it enables precise angular displacement of the detector assembly through closed-loop control based on the real-time spot position detected by the PSD displacement sensor, achieving fine optical path alignment. This device significantly improves optical path adjustment efficiency, achieving an optical path alignment accuracy of over 95%, thereby greatly enhancing the measurement accuracy of the laser gas analyzer. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the connection structure of the device in an embodiment of this utility model.

[0020] In the diagram, 1. Laser emitting unit, 2. Laser receiving unit, 3. Equipment flange, 4. Instrument mounting flange, 5. Air inlet valve, 6. Laser emitter, 7. Cable, 8. Measuring pipe.

[0021] Figure 2 This is a schematic diagram of the laser receiving unit in the embodiment.

[0022] In the diagram, 2-1. Glass window, 2-2. Window cover, 2-3. O-ring, 2-4. Detector base, 2-5. Screw, 2-6. Detector assembly, 2-7. Support platform, 2-8. Power base plate, 2-9. Lead screw, 2-10. Stepper motor, 2-11. Transmission device, 2-12. Power unit. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the embodiments and accompanying drawings. Example

[0024] Reference Appendix: Online Optical Path Alignment Device for Laser Oxygen Analyzer Figure 1 It mainly includes a laser emitting unit 1 and a laser receiving unit 2, which are coaxially aligned and placed on both sides of the measuring pipe 8; the laser emitting unit 1 and the laser receiving unit 2 are connected by a cable 7; the laser emitting unit 1 includes an instrument control system and a laser emitter.

[0025] In this embodiment, the equipment flange 3 is coaxially welded through both ends of the measuring pipe 8. The laser emitting unit 1 is installed on one side of the measuring pipe through the instrument mounting flange 4, the air inlet valve 5, and the equipment flange 3. A coarse adjustment mechanism is provided between the laser emitting unit 1 and the measuring pipe 8, including an O-ring and bolts placed between the flanges of the instrument mounting flange 4 and the air inlet valve 5. The bolts include 4 M16 balance bolts and 4 M10 internal hexagonal fixing bolts. The optical path can be coarsely adjusted by adjusting the M16 bolts (used when the optical path deviation is too large).

[0026] In this embodiment, the laser receiving unit 2 is installed on the other side of the measuring pipe 8 via the instrument mounting flange 4, the air outlet valve, and the equipment flange 3.

[0027] Reference Appendix Figure 2 The laser receiving unit 2 mainly includes a glass window 2-1 and a detector assembly 2-6. The detector assembly 2-6 is equipped with a centering and fine-tuning mechanism, which includes, in sequence, a window cover plate 2-2 for fixing the glass window 2-1, an O-ring 2-3, a detector base 2-4, and a power unit 2-12 placed on a support platform 2-7. The window cover plate 2-2 and the detector base 2-4 are connected by screws 2-5. The power unit 2-12 includes a stepper motor 2-10, a transmission device 2-11, and a lead screw 2-9 mounted on a power base plate 2-8. The top end of the lead screw 2-9 is connected to the screw 2-5 and can drive the screw 2-5 to rotate.

[0028] In this embodiment, the transmission device 2-11 includes a flexible coupling, an angular contact bearing, and a sliding telescopic shaft, etc., to enable the stepper motor 2-10 to drive the lead screw 2-9 to rotate, thereby achieving the linear motion of the screw 2-5.

[0029] In this embodiment, the viewing window cover 2-2 is hollow, and the back is provided with an O-ring 2-3 limiting groove and a screw hole corresponding to the screw 2-5; the O-ring 2-3 has a certain thickness, and the angle of the detector base 2-4 can be adjusted by rotating the screw 2-5; the detector base 2-4 and the detector assembly 2-6 are connected by a pluggable connection structure.

[0030] In this embodiment, the detector base 2-4 is hollow and has a groove, with through screw holes corresponding to the screws 2-5 around it; the detector assembly 2-6 has a locking boss on one side of its front end that matches the groove, and a limiting boss on the other side of its rear end; the limiting boss and the detector base 2-4 have corresponding threaded fixing holes. Through the above-mentioned pluggable structure, the locking boss can control the orientation of the detector assembly 2-6 inserted into the detector base 2-4, and the limiting boss can control the depth of the detector assembly 2-6 inserted into the detector base 2-4. After being inserted into place, the two can be fixed by the threaded fixing holes, thus ensuring that the detector base and the detector assembly can only be fixed in one position.

[0031] In this embodiment, screw 2-5 includes 4 hexagon socket screws that are adapted to the ball joints at the top of 4 lead screws 2-9.

[0032] In this embodiment, detector assembly 2-6 includes two replaceable and pluggable detector assemblies with identical appearance and concentricity, which are divided into detector optical path debugging assembly and detector detection assembly; detector optical path debugging assembly includes PSD displacement sensor, and detector detection assembly includes photodetector, which can be selected and plugged in according to the working requirements of the instrument.

[0033] In this embodiment, the glass window 2-1 is explosion-proof glass of a certain thickness, which is glued to the left window and fastened by the window cover plate 2-2; the back of the window cover plate 2-2 is provided with a groove to prevent the O-ring 2-3 from shifting; the O-ring 2-3 is placed between the window cover plate 2-2 and the detector base 2-4 and is connected by screws 2-5. By tightening the four screws to different degrees, the detector base 2-4 is at a certain angle, which realizes the function of fine adjustment of the optical path; there are two detector components 2-6, which can be connected to the detector base 2-4 through bosses, grooves and limiting holes, and can be positioned and inserted according to functional requirements; the power unit 2-12 is an integral unit and is connected to the support platform 2-7 through a lock nut, which is convenient for use and removal.

[0034] In the embodiment, when the laser oxygen analyzer is working normally, the detector assembly 2-6 selects the detector detection assembly (photodetector) and removes the power unit 2-12.

[0035] When the laser oxygen analyzer needs to be centered and adjusted online, the detector assembly 2-6 is selected as the detector optical path adjustment assembly (PSD displacement sensor) and equipped with the power unit 2-12. Once the instrument is powered on and the optical path debugging interface is accessed, the control system rotates stepper motor 2-10, causing the sliding telescopic shaft in transmission device 2-11 to return to its initial position. The real-time spot position information transmitted by detector assembly 2-6 can be viewed on the optical path debugging interface. If no position information is available (due to significant optical path deviation), coarse optical path alignment can be performed using the bolts on instrument mounting flange 4. If available, clicking the optical path optimization button on the interface will cause the control system to calculate the offsets ΔX and ΔY relative to the center origin based on the spot position coordinates. An algorithm will then generate pulse control signals to drive stepper motor 2-10, controlling lead screw 2-9 to move forward or backward to achieve linear motion of screw 2-5. By varying the strokes of the four screws 2-5, the precise angular displacement of detector assembly 2-6 is controlled, achieving fine-tuning of the optical path alignment and ensuring the optical path is collimated at the center. Exiting the debugging interface and powering off the instrument, the power unit 2-12 is removed, and the detector assembly (photodetector) is reinstalled. Powering on again will allow the instrument to function normally.

[0036] In this embodiment, the photodetector in the detector detection assembly has a photosensitive surface of only Ф3mm, the laser beam for oxygen measurement is Ф1~3mm, the glass window is Ф50mm, and the length of the measuring pipe is generally Ф800~1000mm. Because the pipe span is long and the photosensitive surface for receiving signals is narrow, the conventional manual adjustment of the optical path has very low light efficiency.

[0037] In this embodiment, the photosensitive surface of the PSD displacement sensor in the detector optical path debugging assembly is 25mm x 25mm. When the instrument is installed for the first time and the laser emitting unit, equipment flange and receiving unit are coaxial, the laser signal spot will be within the 25mm x 25mm receiving area when it is disassembled and reassembled. If the offset is too large, the spot can be quickly adjusted to the 25mm x 25mm receiving area by conventional manual adjustment (coarse adjustment).

[0038] Any aspects not described in this embodiment are existing technologies well-known in the field.

Claims

1. An online optical path alignment device for a laser oxygen analyzer, characterized in that... It includes a laser emitting unit and a laser receiving unit coaxially aligned on both sides of the measuring pipe; the laser emitting unit and the laser receiving unit are connected by a cable; the laser emitting unit includes an instrument control system and a laser emitter, and a coarse adjustment mechanism is provided between the laser emitting unit and the measuring pipe; the laser receiving unit includes a glass window and a detector assembly, and the detector assembly is equipped with a fine adjustment mechanism.

2. The online optical path alignment device for a laser oxygen analyzer according to claim 1, characterized in that... The laser emitting unit is mounted on one side of the measuring pipeline via an instrument mounting flange, an air inlet valve, and an equipment flange; the centering coarse adjustment mechanism includes an elastic body and bolts placed between the instrument mounting flange and the air inlet valve flange.

3. The online optical path alignment device for a laser oxygen analyzer according to claim 2, characterized in that... The bolts include four M16 balancing bolts and four M10 internal hexagonal retaining bolts; the elastomer is an O-ring.

4. The online optical path alignment device for a laser oxygen analyzer according to claim 1, characterized in that... The laser receiving unit is installed on the other side of the measuring pipeline via an instrument mounting flange, an exhaust valve, and an equipment flange.

5. The online optical path alignment device for a laser oxygen analyzer according to claim 1, characterized in that... The centering and fine-tuning mechanism includes, in sequence, a window cover plate for fixing the glass window, an elastomer, a detector base, and a power unit connected to the support platform lock nut. The window cover plate and the detector base are connected by screws. The power unit is an integral unit, including a stepper motor, a transmission device, and a lead screw mounted on the power base plate. The top of the lead screw is connected to the screw and can drive the screw to rotate.

6. The online optical path alignment device for a laser oxygen analyzer according to claim 5, characterized in that... The transmission device includes a flexible coupling, an angular contact bearing, and a sliding telescopic shaft.

7. The online optical path alignment device for a laser oxygen analyzer according to claim 5, characterized in that... The viewing window cover is hollow and has an elastic body limiting groove on the back; the screws include four internal hex screws that are adapted to the ball at the top of four lead screws; the elastic body has a certain thickness and can adjust the angle of the detector base through the screws, and the elastic body is an O-ring; the detector base has a connection structure for pluggable detector components.

8. The online optical path alignment device for a laser oxygen analyzer according to claim 7, characterized in that... The detector base is hollow and has a groove. The front side of the detector assembly has a locking boss that matches the groove, and the rear side has a limiting boss. The limiting boss and the detector base have corresponding threaded fixing holes.

9. The online optical path alignment device for a laser oxygen analyzer according to claim 1 or 7, characterized in that... The detector assembly includes two replaceable and pluggable detector assemblies with identical appearance and concentricity, which are divided into a detector optical path debugging assembly and a detector detection assembly.

10. The online optical path alignment device for a laser oxygen analyzer according to claim 9, characterized in that... The detector optical path adjustment component includes a PSD displacement sensor, and the detector detection component includes a photodetector.

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