Composite laser measurer

Abstract

The utility model discloses a composite laser measurer, which comprises a laser emitting end and a laser receiving end, the laser emitting end and the laser receiving end are symmetrically arranged on two side walls of a heating box, outer pipes are arranged on the laser emitting end and the laser receiving end, the two outer pipes are positioned in the heating box, and the laser emitting end and the laser receiving end are connected with each other. A gas distributor is arranged between the two outer pipes in a sealed mode, a mounting hole and a backflow hole are formed in the gas distributor, a sample gas inlet and a sample gas outlet are formed in the gas distributor, an inner pipe is arranged in the mounting hole in a sealed mode, an inner through hole is formed in the inner pipe, and a gas conveying pipe for conveying sample gas is connected to the sample gas inlet. A sampling pump is arranged on the gas conveying pipe, a branch pipe is connected to the gas conveying pipe, a three-way valve is arranged on the branch pipe, one end of the three-way valve is connected with a zero-point gas source, and the other end of the three-way valve is communicated with a standard gas source. The utility model has the advantage that the measuring precision can be improved.

Description

Technical Field

[0001] This utility model relates to the field of flue gas emission monitoring technology, and in particular to a composite laser measuring device. Background Technology

[0002] When using conventional analytical instruments to detect process gases in the metallurgical and coal chemical industries, it is necessary to reduce the temperature and dust content of the sample gas. Dust removal can be achieved by filtering the sample during sampling, which does not affect the content of individual gas components. However, cooling the sample gas requires passing it through washing water before drying. Gases readily soluble in water, such as ammonia, sulfur dioxide, and hydrogen sulfide, will dissolve in the washing water, making it difficult for conventional analytical instruments to accurately measure the components and their concentrations. Therefore, to solve this problem, laser measurement equipment has emerged. The process gas sample only needs to be dust-removed before being fed into the laser measurement equipment. The equipment determines the components and their concentrations by analyzing the intensity changes or scattered light characteristics after the laser passes through the gas, offering high measurement efficiency and accuracy.

[0003] Currently available laser measuring instruments include Figure 1 As shown, the device includes a laser emitter and a laser receiver. Both the laser emitter and receiver have purge holes. A measuring tube is sealed between the laser emitter and receiver. A sample gas inlet is located on the upper side wall of the measuring tube, and sample gas outlets are located at both ends of the lower side wall. The process sample gas enters the measuring tube through the sample gas inlet, while nitrogen gas is blown into the measuring tube through the purge holes on the laser emitter and receiver. The nitrogen acts as a barrier, preventing the process sample gas from contacting and damaging the optical windows in the laser emitter and receiver. Since the sample gas outlets are located at both ends of the measuring tube, both the blown nitrogen and the process sample gas are directly discharged from these outlets. This leads to excessive mixing between the nitrogen and the process sample gas, diluting the process sample gas and causing inaccurate measurements. Furthermore, the process sample gas has a higher temperature and is prone to condensation after directly entering the measuring tube. The resulting water stains can dissolve soluble gases in the process sample gas, further affecting measurement accuracy. Utility Model Content

[0004] The purpose of this invention is to provide a composite laser measuring instrument that can avoid excessive mixing of nitrogen and process sample gas and prevent condensation.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is: a composite laser measuring device, comprising: a laser emitting end and a laser receiving end, both of which are provided with purge holes. The laser emitting end and the laser receiving end are symmetrically arranged on the two side walls of a heating chamber. Both the laser emitting end and the laser receiving end are provided with outer tubes. The two outer tubes are located inside the heating chamber. A gas distributor is sealed between the two outer tubes. The gas distributor is provided with mounting holes and reflux holes. The system is equipped with a sample gas inlet and a sample gas outlet, which are respectively connected to the mounting hole and the reflux hole. An inner tube is sealed in the mounting hole, and an inner through hole connected to the sample gas inlet is provided on the inner tube. The length of the inner tube is the effective measurement optical path. A gas delivery pipe for delivering sample gas is connected to the sample gas inlet. A sampling pump is provided on the gas delivery pipe. A branch pipe is connected to the gas delivery pipe, and a three-way valve is provided on the branch pipe. One end of the three-way valve is connected to the zero-point gas source through the zero-point gas pipe, and the other end of the three-way valve is connected to the standard gas source through the standard gas pipe.

[0006] Furthermore, in the aforementioned composite laser measuring device, a pressure-pressurizing vent screw is threadedly connected to the sample gas inlet. The pressure-pressurizing vent screw abuts against the inner tube, and the through hole in the pressure-pressurizing vent screw is connected to the inner through hole on the inner tube.

[0007] Furthermore, in the aforementioned composite laser measuring device, heat insulation rings are provided on both sides of the heating box, and reducing flanges are sealed in the heat insulation rings. One end of the two reducing flanges extends into the heating box and is connected to two outer tubes respectively through the flanges. The other end of the two reducing flanges extends out of the heating box and is connected to the laser emitting end and the laser receiving end respectively.

[0008] Furthermore, in the aforementioned composite laser measuring device, a spiral heating element is provided at the end of the outer tube away from the gas distributor.

[0009] Furthermore, in the aforementioned composite laser measuring device, a heating cable is wound around the gas supply pipe.

[0010] Furthermore, in the aforementioned composite laser measuring device, the central axis of the inner tube coincides with the central axes of the two outer tubes.

[0011] Furthermore, in the aforementioned composite laser measuring device, the connection structure between the two outer tubes and the gas distributor is as follows: a flange is welded to one end of the outer tube near the gas distributor; annular grooves are provided on both sides of the gas distributor; sealing rings are fitted in the annular grooves; the flanges on the two outer tubes abut against the sealing rings on both sides of the gas distributor; the two flanges are connected by bolts, with the bolts avoiding the sample gas inlet and sample gas outlet.

[0012] The advantages of this invention are as follows: First, a standard gas containing the same components as the process sample gas to be tested, with each component at its self-prepared concentration, is introduced into the inner tube. The standard gas fills the inner tube and then diffuses into the outer tube. The diffused standard gas in the outer tube mixes with nitrogen at both ends of the inner tube, preventing nitrogen from entering the inner tube and thus reducing the amount of nitrogen mixed with the standard gas. The laser emitter and receiver can then measure and analyze the standard gas in the inner tube. By comparing the measured concentrations of each component with their self-prepared concentrations, the measurement error can be determined. Then, the process sample gas is... The sample gas is introduced into the inner tube for measurement and analysis. By combining the measured concentration of each component in the process sample gas with the measurement error, the designed concentration of each component in the process sample gas can be obtained, which greatly improves the measurement accuracy. The inner and outer tubes are placed in a heating chamber, which can heat the inner and outer tubes. When the high-temperature process sample gas enters the high-temperature inner and outer tubes, condensation will not occur. The spiral heating fins on the outer tube can further heat the injected nitrogen gas, so that the high-temperature process sample gas will not condense when it comes into contact with nitrogen gas. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a conventional laser measuring instrument.

[0014] Figure 2 This is a schematic diagram of the structure of the composite laser measuring device described in this utility model.

[0015] Figure 3 yes Figure 2 A schematic diagram of the gas distributor. Detailed Implementation

[0016] The technical solution of this utility model will be further described below with reference to the accompanying drawings and preferred embodiments.

[0017] like Figure 2 , Figure 3As shown, the composite laser measuring device of this utility model includes: a laser emitting end 1 and a laser receiving end 2. Both the laser emitting end 1 and the laser receiving end 2 are provided with purge holes 11, which are connected to a nitrogen gas source. Both the laser emitting end 1 and the laser receiving end 2 are connected with reducing flanges 31. The two reducing flanges 31 are sealed and fixed to the two side walls of the heating chamber 3 by heat insulation rings 32. One end of the two reducing flanges 31 connected to the laser emitting end 1 and the laser receiving end 2 is located outside the heating chamber 3, so that the laser emitting end 1 and the laser receiving end 2 are not affected by high temperature. The other end of the two reducing flanges 31 extends into the heating chamber 3, and an outer tube 4 is connected to this end by a flange. The two outer tubes 4 are located in the heating chamber 3, and are connected to the reducing flanges... A spiral heating element 41 is installed at the end of the outer tube 4 connected to the 31. A gas distributor 5 is sealed between the two outer tubes 4. The connection structure between the two outer tubes 4 and the gas distributor 5 is as follows: a flange 42 is welded to the end of the outer tube 4 near the gas distributor 5. Annular grooves are provided on both sides of the gas distributor 5, and sealing rings 51 are fitted in the annular grooves. The flanges 42 on the two outer tubes 4 respectively abut against the sealing rings 51 on the two sides of the gas distributor 5. The two flanges 42 are connected by bolts. The gas distributor 5 is provided with a mounting hole 52 and a return hole 53. The gas distributor 5 is provided with a sample gas inlet 54 and a sample gas outlet 55, which are respectively connected to the mounting hole 52 and the return hole 53. The gas outlets 55 are offset from the bolts. An inner tube 6 is sealed in the mounting hole 52. The inner tube 6 is coaxial with the two outer tubes 4. An inner through hole is provided on the inner tube 6, which is connected to the sample gas inlet 54. A clamping vent screw 541 is threaded into the sample gas inlet 54. The clamping vent screw 541 is pressed against the inner tube 6 to fix the inner tube 6. At the same time, the through hole in the clamping vent screw 541 is connected to the inner through hole on the inner tube 6. The length of the inner tube 6 is the effective measurement optical path of the laser measuring instrument. The laser emitting end 1 and the laser receiving end 2 can only measure the gas in the inner tube 6. A gas delivery pipe 7 for delivering sample gas is connected to the sample gas inlet 54. The gas delivery pipe 7 does not interfere with the bolts. A sampling pump and a heating cable are installed on the gas delivery pipe 7. The sampling pump and heating cable are not shown in the figure. A branch pipe 71 is connected to the gas supply pipe 7. A three-way valve 72 is installed on the branch pipe 71. One end of the three-way valve 72 is connected to the zero-point gas source through the zero-point gas pipe 73. The zero-point gas in the zero-point gas source refers to the basic gas of high-purity nitrogen or clean air that does not contain the components to be tested. The other end of the three-way valve 72 is connected to the standard gas source through the standard gas pipe 74. The standard gas in the standard gas source refers to a mixed gas with known components and concentrations of each component. In this embodiment, the components of the standard gas are the same as those of the process sample gas to be tested, and the concentrations of each component are self-prepared concentrations. An exhaust pipe 56 is connected to the sample gas outlet 55. The exhaust pipe 56 does not interfere with the bolts. The exhaust pipe 56 extends out of the heating box 3 and is connected to the tail gas collection device.

[0018] Before conducting formal measurements, the sealing performance of the inner tube 6 and outer tube 4 needs to be checked, and the measurement error needs to be calibrated. First, switch the three-way valve 72 to the zero-point gas pipe 73 passage. The zero-point gas from the zero-point gas source is delivered to the sample gas inlet 54, and then enters the inner tube 6, outer tube 4, and reducing flange 31 through the tightening vent screw 541 and the inner through hole, replacing the residual gas in the inner tube 6, outer tube 4, and reducing flange 31. During this process, the laser emitting end 1 and the laser receiving end 2 maintain measurement operation, and nitrogen is not sprayed into the purging hole 11. When the laser emitting end 1... If no analyte is measured at laser receiver 2, it indicates that the inner tube 6, outer tube 4, and reducing flange 31 are filled with zero-point gas. Then, the three-way valve 72 is switched to the standard gas pipe 74 passage, and the standard gas from the standard gas source is delivered to the sample gas inlet 54. At this time, the purge port 11 of laser transmitter 1 and laser receiver 2 is opened. The nitrogen gas sprayed from purge port 11 has a lower spray pressure than the standard gas delivery pressure. Since the inner tube 6, outer tube 4, and reducing flange 31 were originally filled with zero-point gas, and the nitrogen gas sprayed from purge port 11 mixes with the zero-point gas, the standard gas enters... After entering the inner tube 6, because the delivery pressure is greater than the nitrogen injection pressure, the standard gas gradually forces the mixture of zero-point gas and nitrogen out of the inner tube 6. Once the inner tube 6 is full of standard gas, it flows from both ends of the inner tube 6 into the outer tube 4 for diffusion. The pressure of the standard gas flowing into the outer tube 4 decreases, thus offsetting the pressure of the nitrogen. This causes the nitrogen and standard gas to mix at the end of the inner tube 6, creating a gas seal. The mixture of standard gas and nitrogen diffuses and flows in the outer tube 4, then flows through the return hole 53 into the sample gas outlet 55, and is finally discharged from the exhaust pipe 56. (Laser emission...) End 1 and laser receiving end 2 measure and analyze the standard gas in inner tube 6 to obtain the measured concentration of each component in the standard gas. At this time, because of the influence of nitrogen at the end of inner tube 6, the measured concentration of each component in the standard gas is lower than the self-prepared concentration of each component in the standard gas. A difference will appear between the measured concentration and the self-prepared concentration of each component, and this difference is the measurement error. When the process sample gas is measured and analyzed in the subsequent process, the composite laser measuring instrument will automatically combine the measured concentration of each component with the corresponding difference to obtain the self-prepared concentration of each component in the process sample gas.

[0019] After calibration, the three-way valve 72 is closed, and the sampling pump delivers the process sample gas to the gas delivery pipe 7, which then enters the inner pipe 6 for measurement and analysis. The delivery pressure of the sampling pump is consistent with the delivery pressure of the standard gas, and the nitrogen pressure in the purge port 11 is maintained at the calibration pressure value. This ensures that the mixing state of nitrogen and process sample gas is similar to that of nitrogen and standard gas during normal measurement and analysis. This allows the measurement error obtained during calibration to be combined with the measured concentration of each component in the process sample gas to obtain the actual concentration of each component in the process sample gas. During normal measurement and analysis, the process sample gas has a high temperature. If it directly enters the gas supply pipe 7 and the inner pipe 6, condensation will occur in the inner pipe 6 and the gas supply pipe 7, resulting in water output and affecting the measurement accuracy. Therefore, before normal measurement, it is necessary to start the heating cable and the heating box 3. The heating cable heats the gas supply pipe 7, and the heating box 3 heats the inner pipe 6 and the outer pipe 4. In this way, condensation will not occur when the process sample gas enters the gas supply pipe 7 and the inner pipe 6. However, when the nitrogen in the purge hole 11 is blown into the outer pipe 4 at room temperature, the high temperature process sample gas in the outer pipe 4 will come into contact with the room temperature nitrogen and condensation will occur, affecting the measurement accuracy. Therefore, when the heating box 3 is heating, the spiral heating plate 41 on the outer pipe 4 is heated so that the nitrogen can be heated when it enters the outer pipe 4, preventing the process sample gas from condensing.

[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model should be covered within the protection scope of the claims of this utility model.

Claims

1. A composite laser measuring instrument, including: The laser emitter and receiver are equipped with purge holes on both sides. The laser emitter and receiver are symmetrically arranged on the two side walls of a heating chamber. Both emitters and receivers have outer tubes located within the heating chamber. A gas distributor is sealed between the two outer tubes, containing an installation hole and a reflux hole. The gas distributor also has a sample gas inlet and outlet connected to the installation hole and reflux hole, respectively. An inner tube is sealed within the installation hole, with an internal through-hole connected to the sample gas inlet. The length of the inner tube is the effective optical path length. A gas delivery pipe for transporting sample gas is connected to the sample gas inlet. A sampling pump is installed on the gas delivery pipe. A branch pipe is connected to the gas delivery pipe, and a three-way valve is installed on the branch pipe. One end of the three-way valve is connected to a zero-point gas source via a zero-point gas pipe, and the other end is connected to a standard gas source via a standard gas pipe.

2. The composite laser measuring device according to claim 1, characterized in that: A pressure-tightening vent screw is threaded into the sample gas inlet. The pressure-tightening vent screw is pressed against the inner tube, and the through hole in the pressure-tightening vent screw is connected to the inner through hole on the inner tube.

3. The composite laser measuring device according to claim 1, characterized in that: Insulation rings are installed on both sides of the heating chamber. A reducing flange is sealed in the insulation ring. One end of the two reducing flanges extends into the heating chamber and is connected to the two outer pipes respectively. The other end of the two reducing flanges extends out of the heating chamber and is connected to the laser emitting end and the laser receiving end respectively.

4. The composite laser measuring device according to claim 1, characterized in that: A spiral heating element is installed at the end of the outer tube away from the gas distributor.

5. The composite laser measuring device according to claim 1, characterized in that: A heat tracing cable is wound around the gas pipeline.

6. The composite laser measuring device according to claim 1, characterized in that: The central axis of the inner tube coincides with the central axes of the two outer tubes.

7. The composite laser measuring device according to claim 1, characterized in that: The connection structure between the two outer pipes and the gas distributor is as follows: a flange is welded to the end of the outer pipe near the gas distributor, and annular grooves are provided on both sides of the gas distributor. A sealing ring is inserted in the annular groove. The flanges on the two outer pipes abut against the sealing rings on both sides of the gas distributor. The two flanges are connected by bolts, and the bolts avoid the sample gas inlet and sample gas outlet.

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