CN114459829A - Online sampling device and method for air-powder pipe suitable for optical detection technology - Google Patents
Online sampling device and method for air-powder pipe suitable for optical detection technology Download PDFInfo
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- CN114459829A CN114459829A CN202210091399.3A CN202210091399A CN114459829A CN 114459829 A CN114459829 A CN 114459829A CN 202210091399 A CN202210091399 A CN 202210091399A CN 114459829 A CN114459829 A CN 114459829A
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- 238000001514 detection method Methods 0.000 title claims abstract description 160
- 230000003287 optical effect Effects 0.000 title claims abstract description 129
- 239000000843 powder Substances 0.000 title claims abstract description 112
- 238000005070 sampling Methods 0.000 title claims abstract description 75
- 238000005516 engineering process Methods 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims description 20
- 238000007664 blowing Methods 0.000 claims abstract description 84
- 238000007789 sealing Methods 0.000 claims abstract description 22
- 238000011010 flushing procedure Methods 0.000 claims abstract description 20
- 238000009434 installation Methods 0.000 claims abstract description 16
- 230000002093 peripheral effect Effects 0.000 claims abstract description 7
- 230000001105 regulatory effect Effects 0.000 claims description 13
- 238000010926 purge Methods 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 6
- 238000005096 rolling process Methods 0.000 claims description 6
- 239000003245 coal Substances 0.000 description 27
- 239000002817 coal dust Substances 0.000 description 18
- 230000033228 biological regulation Effects 0.000 description 5
- 238000004140 cleaning Methods 0.000 description 5
- 230000003749 cleanliness Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003292 glue Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 229910052594 sapphire Inorganic materials 0.000 description 2
- 239000010980 sapphire Substances 0.000 description 2
- 230000001174 ascending effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/10—Devices for withdrawing samples in the liquid or fluent state
- G01N1/20—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials
- G01N1/2035—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials by deviating part of a fluid stream, e.g. by drawing-off or tapping
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N21/03—Cuvette constructions
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/85—Investigating moving fluids or granular solids
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Abstract
The invention provides an air-powder tube online sampling device suitable for an optical detection technology, which comprises: the connecting pipe is arranged below the air powder pipe; a gas seal unit; the sample loading pipe is arranged below the air sealing unit, is communicated with the connecting pipe, and contains falling powder when the air sealing unit stops air guide; the optical detection window is arranged below the sample loading pipe, and light beams of external optical detection equipment penetrate through the optical detection window so as to detect powder positioned on the optical detection window; the back-blowing unit is arranged between the sample loading pipe and the optical detection window, and is used for removing powder on the optical detection window through back blowing, and comprises a back-blowing cavity and a plurality of back-blowing air inlets; the back flushing cavity is of a multi-lobe semi-ellipsoidal structure, first focuses of all semi-ellipsoidal structures are circumferentially and uniformly distributed on a peripheral installation area of the optical detection window, and second focuses are circumferentially and uniformly distributed in the range of the optical detection window; the back-blowing air inlets are arranged on the peripheral installation area, and each back-blowing air inlet is located at a first focus of the half-ellipsoid structure.
Description
Technical Field
The invention belongs to the technical field of automatic detection equipment of a coal-fired power station, and particularly relates to an online sampling device and method for an air powder pipe, which are suitable for an optical detection technology.
Background
The coal quality of the coal as fired is particularly important for the safety, economy and environmental protection of the operation of the power plant, and determines the overall operation characteristics of the coal-fired boiler and even the coal-fired power plant to a certain extent. With the steady promotion of 'constructing a novel electric power system taking new energy as a main body' in China, the position of a main power supply of a coal-fired power station is gradually changed into an adjustable power supply, so that in order to adapt to a new operation mode with quick load change and large peak regulation requirement under a new energy power grid, quick combustion adjustment and fine control of a boiler become necessary means, and real-time monitoring of coal quality information of as-fired coal becomes a new urgent requirement.
The optical detection technology is very suitable for the field of fast and efficient online detection due to the characteristics of extremely high precision, extremely fast detection speed, small sample demand, no damage and the like, and the existing method for online detecting the coal quality by utilizing the optical detection technology is rapidly developed along with the improvement of the requirement on flexible and accurate combustion control under the background of deep peak regulation. However, optical detection places higher demands on the sampling device: on one hand, optical detection needs to maintain a window with better cleanliness, so that better laser transmittance can be maintained, and detection precision is guaranteed; on the other hand, the quantity of samples required by optical detection is small, and the optical detection is very easily influenced by residual samples, so that the accuracy of detection results is influenced.
Disclosure of Invention
The invention is made to solve the above problems, and an object of the invention is to provide an online sampling device and method for a wind-powder duct, which are suitable for an optical detection technology, and can realize efficient, rapid and accurate sampling of pulverized coal in the wind-powder duct, and simultaneously ensure cleanliness of a window and effective removal of residual samples to the maximum extent.
In order to achieve the purpose, the invention adopts the following scheme:
< apparatus >
The invention provides an online sampling device of a wind powder pipe suitable for an optical detection technology, which is characterized by comprising the following components: the connecting pipe is connected with an air-powder pipe for conveying powder (such as coal powder) and is arranged below the air-powder pipe; the air outlet is arranged around the inner wall of the connecting pipe, and external air flow is led in through the air outlet to form positive pressure in the connecting pipe so as to prevent the powder from falling; the sample loading pipe is arranged below the air sealing unit, is communicated with the connecting pipe, and contains falling powder when the air sealing unit stops air guide; the optical detection window is arranged below the sample loading pipe, and light beams of external optical detection equipment penetrate through the optical detection window so as to detect powder positioned on the optical detection window; the back-blowing unit is arranged between the sample loading pipe and the optical detection window, and is used for removing powder on the optical detection window through back blowing, and comprises a back-blowing cavity and a plurality of back-blowing air inlets; the back-blowing cavity is arranged around the bottom of the sample containing pipe and is of a multi-petal semi-ellipsoidal structure, a back-blowing space is formed, the interior of the back-blowing space is hollow and communicated with the sample containing pipe, the periphery of the back-blowing space is outward expanded towards the installation area of the optical detection window, first focuses of all the semi-ellipsoidal structures are circumferentially and uniformly distributed on the peripheral installation area of the optical detection window, second focuses are circumferentially and uniformly distributed in the range of the optical detection window, and the second focuses of the semi-ellipsoidal structures are located on the other side, opposite to the first focuses, of the center point of the window; the back-blowing air inlets are arranged on the peripheral installation area, and each back-blowing air inlet is located at a first focus of the half-ellipsoid structure.
The beneficial effect of above scheme does:
due to the structure, when sampling detection is needed, a back-blowing air inlet is adopted to introduce back-blowing air flow for multiple times to clean a back-blowing cavity and an optical detection window, then an air sealing unit stops air inlet, powder can rapidly fall and deposit on the optical detection window, and detection data can be obtained by detecting the powder through the optical detection window by using an optical detection technology to finish detection; then, a back-blowing air inlet is opened to send back-blowing air flow, the back-blowing air flow is sprayed out from a first focus of an ellipsoidal cavity (an ellipsoidal structure), then is reflected and converged to a second focus positioned on a window (an optical detection window) through a cavity wall, the position and the surrounding position are blown and swept, back-blowing air formed after the back-blowing air flow sprayed out from each back-blowing air inlet is emitted through each ellipsoidal cavity is overlapped in a main body area of the window and covers the whole window range of the back-blowing air flow, so that the air flow can be blown to the window from different circumferential directions, all areas of the window, particularly the main body area can be effectively blown and swept, all powder remained on the window is lifted and is sucked by an air sealing unit and sent back to a powder pipe, the back-feeding of the powder after detection and the blowing-off of the powder on the window can be realized, and the powder residue in the detection area can be furthest ensured, the cleanness of the window and the accuracy of an optical detection result are ensured; furthermore, the second focus of the ellipsoidal cavity is positioned on the other side of the central point of the window, so that the blown airflow can keep a large inclination angle (non-vertical) and residual powder is prevented from being pressed and adhered to the window due to back blowing.
In addition, the whole sampling device utilizes the positive pressure of the air powder pipe and the powder gravity to directly sample the air powder pipe, is simple and reliable, and has no part directly brushed by the air powder due to the existence of the air sealing unit when the sampling is not carried out, thereby ensuring the service life of the sampling device.
In conclusion, the online sampling device for the air powder pipe, which is suitable for the optical detection technology, can realize efficient, rapid and accurate sampling and optical detection of the air powder pipe powder, simultaneously furthest ensures the cleanliness of a window and the effective removal of residual samples, has a simple structure and long service life, particularly does not consume any powder when being used for sampling and detecting, does not need to take the powder out of the device for detection, avoids material loss, and greatly improves the sampling and detecting efficiency.
Preferably, the online sampling device for the wind powder pipe suitable for the optical detection technology according to the present invention may further have the following features: the installation lid sets up in blowback unit bottom for sealed installation optical detection window includes: the fixing piece is detachably used for fixedly fastening the upper cover ring and the lower cover ring of the optical detection window in a sealing and clamping manner from the upper side and the lower side; wherein, the bottom of blowback air inlet runs through the installation lid. The detachable installation of the optical detection window is realized through the structural design, and the maintenance and the replacement after long-time use are convenient.
Preferably, the online sampling device for the wind powder pipe suitable for the optical detection technology according to the present invention may further include: the back flushing cavity comprises at least four semi-ellipsoidal structures, and the more the number of the lobes is, the more the overlapped area is; the minimum inner diameter of the back flushing cavity is equal to the inner diameter of the sample loading pipe and the inner diameter of the connecting pipe.
Preferably, the online sampling device for the wind powder pipe suitable for the optical detection technology according to the present invention may further have the following features: the back-blowing cavity comprises a six-lobe semi-ellipsoidal structure, the number of lobes of the structure is moderate, the manufacture is easy, and the back-blowing effect is very good.
Preferably, the online sampling device for the wind powder pipe suitable for the optical detection technology according to the present invention may further have the following features: the semi-ellipsoidal structure is not an ellipse with a half section, but a part of the semi-ellipsoidal structure left after the intersection of the semi-ellipsoidal structure and the sample containing tube and the intersection of the adjacent semi-ellipsoidal structure are cut off.
Preferably, the online sampling device for the wind powder pipe suitable for the optical detection technology according to the present invention may further have the following features: the bottom end of the connecting pipe is arranged at a certain distance from the upper end of the sample loading pipe, the bottom end of the connecting pipe extends downwards and outwards in an inclined manner, the upper end of the sample loading pipe also extends downwards and outwards in an inclined manner to jointly enclose a circle of conical annular gas seal gas outlet, a circle of gas seal gas guide cavity is further formed below the outer side of the upper end of the sample loading pipe, and at least two gas seal gas inlet holes are uniformly formed in the outer wall of the gas seal gas guide cavity; the connecting pipe is adjustably connected with the sample containing pipe through adjusting bolts uniformly arranged on the periphery, and the adjusting bolts extend along the axial direction of the connecting pipe and the sample containing pipe; the middle part of the adjusting bolt is polygonal, the upper part and the lower part are both provided with threads, and the middle part is rotated to drive the upper and lower screw rods to rotate to adjust the relative position of the adjusting connecting pipe and the sample containing pipe, so that the size of the air outlet of the air seal is adjusted; the air seal air outlet, the air seal air guide cavity and the air seal air inlet jointly form an air seal unit. The adjusting bolts which are uniformly distributed in the circumferential direction can adjust the relative positions of the connecting pipe and the sample loading pipe in multiple directions to ensure the horizontal and vertical relation of assembly, enhance the reliability of connection, ensure the stable connection of the sampling device, reduce the space occupation to the maximum extent and ensure that the sampling device has a relatively small structure, thereby reducing the influence on the temperature of the wind powder pipe and the like; the interval between two parts of subassemblies can be changed through adjusting bolt's rotation, cooperation atmoseal air inlet and admit air current, form the ascending air current of slant to when atmoseal air inlet had suitable air current to introduce, pass through the air current with the interior wind powder of wind powder pipe and seal intraductally, and do not get into the sampling device bottom.
< method >
Further, the present invention also provides an online sampling method for an air-powder duct suitable for an optical detection technology, which adopts the online sampling device for an air-powder duct described in any one of the above < devices > to perform sampling, and is characterized in that: when the sampling is not carried out, the air seal unit is adopted to continuously introduce air flow to form air seal, so that powder of the air powder pipe is prevented from falling into the sample loading pipe; during sampling, the air sealing unit stops air inlet, keeps the back-blowing air inlet closed, quickly drops powder, deposits on the optical detection window, and then detects the powder through the optical detection window by using an optical detection technology; after the detection is finished, air flow is introduced by adopting an air seal unit, negative pressure is formed at the sample loading pipe, most of powder in the sample loading pipe is sucked into the air return powder pipe in a rolling mode, a back-blowing air inlet is opened to introduce back-blowing air flow with small air pressure, and the powder remained on the optical detection window is blown up to be sucked into the air return powder pipe in a rolling mode. This method also has the corresponding advantageous effects described in the above < device > section.
Preferably, the online sampling device for the wind powder pipe suitable for the optical detection technology according to the present invention may further have the following features: before sampling, a back-blowing air flow is introduced from a back-blowing air inlet for multiple times to clean the back-blowing cavity and the optical detection window before sampling, so that the cleanness of the window can be further ensured, and the accuracy of the detection result is further improved; after the detection is finished and the back-blowing air inlet is opened for continuous blowing for a period of time, back-blowing airflow is intermittently introduced for back blowing, and pressure and flow velocity distribution in the back-blowing cavity can be disturbed by intermittently introducing the back-blowing airflow, so that residual coal powder is cleaned more effectively.
Preferably, in the online sampling device for a dust blowing pipe suitable for the optical detection technology, the specific operation method for intermittently introducing the back blowing airflow for back blowing comprises the following steps: setting the air pressure of the back-blowing air flow to be P1, opening the back-blowing for a certain time t1, closing for a plurality of seconds, and repeating for a plurality of times; regulating the pressure regulating valve to P2, opening the back flushing for a certain time t2, closing for a plurality of seconds, and repeating for a plurality of times; regulating the pressure regulating valve to P3, opening the back flushing valve for a certain time t3, closing for several seconds, and repeating for several times; p1 < P2 < P3, t1 > (t2+3s) > (t3+3 s). During intermittent type nature blowback, blowback pressure is by little and big, through little pressure air current when remaining powder is more (for follow-up blowback condition relatively), relatively long time blowback, when can clear away remaining buggy better, effectively avoid pressing of pressing close to the window buggy to glue, when remaining powder is less, adopt the short blowback of atmospheric pressure, can stir in disorder cavity pressure rapidly, make the buggy break away from window and cavity, the negative pressure suction of cooperation atmoseal, and the remaining buggy that the pressure glued on the window also can effectively be clear away from to great atmospheric pressure, shorter blowback time can also avoid the buggy to be closely pressed to glue on the window under great atmospheric pressure. In addition, for the closing time (interval time), the low-pressure purging time is long, the interval is short, the atmospheric purging time is short, the interval is long, and the window cleaning is facilitated.
Preferably, the online sampling device for the wind powder pipe suitable for the optical detection technology according to the present invention may further have the following features: the continuous purging time is 30-60s, P1 is less than 0.5MPa, P3 is less than 1MPa, t1 is less than 30s, and t3 is less than 8s and is more than 3 s.
Preferably, the online sampling device for the wind powder pipe suitable for the optical detection technology according to the present invention may further have the following features: the control part is adopted to control the air inlet valve of the air seal unit to open and continuously introduce air flow when the sampling is not carried out, so as to form an air seal; a control part is adopted to control an air inlet valve of a back-blowing air inlet to be opened for multiple times before sampling so as to introduce back-blowing air flow and clean a back-blowing cavity and an optical detection window; the control part is adopted to control the closing of an air inlet valve of the air sealing unit and the closing of an air inlet valve of a back flushing air inlet during sampling so that the powder material quickly falls down and is deposited on the optical detection window, and then the optical detector is controlled to detect the powder material through the optical detection window; the control part is adopted to control the air inlet valve of the air sealing unit to be opened after detection is finished, negative pressure is formed at the sample loading pipe, most of powder in the sample loading pipe is sucked into the air return powder pipe in a rolling mode, then the air inlet valve of the back-blowing air inlet is controlled to be opened to introduce back-blowing air flow with small air pressure, and powder remained on the optical detection window is removed. And the specific air pressure regulation is also realized automatically by controlling the corresponding air inlet valve through the control part. Through this, realize before the sample cleaning, sample, detect, clear up the full automation operation and the accurate regulation and control of these processes after detecting, greatly improved detection efficiency for the powder detects can in time, accurately, reliably go on.
Drawings
FIG. 1 is a schematic structural diagram of an online sampling device for an air duct suitable for optical detection technology according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an installation position of an online sampling device of a wind powder pipe suitable for an optical detection technology according to an embodiment of the present invention;
FIG. 3 is a perspective view of an online sampling device for wind-powder tube suitable for optical detection technology according to an embodiment of the present invention;
FIG. 4 is a cross-sectional view of an online sampling device of a wind powder pipe suitable for optical detection technology according to an embodiment of the present invention;
FIG. 5 is a cross-sectional view of a loading tube and a blowback unit formed at the bottom of the loading tube according to an embodiment of the present invention;
FIG. 6 is a perspective view of a loading tube and a blowback unit according to an embodiment of the present invention;
FIG. 7 is a bottom view of the structure of FIG. 5;
FIG. 8 is a schematic diagram illustrating the operation of the blowback unit according to the embodiment of the present invention;
fig. 9 is a schematic view of the covering condition of the optical detection window by the blowback gas according to the embodiment of the present invention.
Detailed Description
The present invention relates to an online sampling device and method for wind powder tube suitable for optical detection technology, which is described in detail below with reference to the accompanying drawings.
< example >
As shown in fig. 1 to 4, an online sampling device 10 for pulverized coal pipes suitable for optical detection technology is installed below a pulverized coal pipe F for conveying pulverized coal in a coal-fired power plant, and includes a connecting pipe 11, an air sealing unit 12, a sample loading pipe 13, an optical detection window 14, a back flushing unit 15, and an installation cover 16.
The connecting pipe 11 is communicated with the transverse section of the wind powder pipe F and is hermetically arranged at the opening of the lower side wall of the wind powder pipe F.
The air outlet 12a of the air sealing unit 12 is disposed around the inner wall of the connection pipe 11, and external air flow is introduced through the air outlet 12a to form positive pressure in the connection pipe 11, thereby preventing the pulverized coal from falling.
The sample loading pipe 13 is arranged below the air seal unit 12 and communicated with the connecting pipe 11, and receives the falling coal powder as a sample to be measured when the air seal unit 12 stops introducing air flow. The sample loading pipe 13 is of a sandwich structure, a circle of base 13a is arranged on the periphery of the sample loading pipe, the upper part of the base 13a is arranged around the outer wall of the lower part of the connecting pipe 11, is connected with the outer convex part of the upper part of the connecting pipe 11 through an adjusting bolt 12d and is sealed by an air seal sealing ring 12e, and four air seal air inlet holes 12b are uniformly arranged on the lower part of the base 13a in the circumferential direction; a ring-shaped air seal air guide cavity 12c is formed in the interlayer; the inner wall 13b of the sample tube 13 is formed corresponding to the inner wall of the connecting tube 11, and the diameter of the inner wall 13b is equal to that of the inner wall of the connecting tube 11.
As shown in fig. 2 and 3, the bottom end of the connecting pipe 11 is spaced from the upper end of the sample holding pipe 13 by a certain distance, the bottom end of the connecting pipe 11 extends downward and inclines outward, the upper end of the sample holding pipe 13 also extends downward and inclines outward, a circle of conical annular air seal air outlet 12a is enclosed together, the outside of the air seal air outlet 12a is an air seal air guide cavity 12c, the outer wall of the air seal air guide cavity 12c is provided with an air seal air inlet 12b, and the air seal air inlet 12b is connected with an external air inlet pipe. The air current gets into air seal air guide cavity 12c through air seal inlet hole 12b, and then flows out by air seal gas outlet 12a to form the malleation above air seal gas outlet 12a and prevent that the buggy from falling into dress appearance pipe 13, form the negative pressure simultaneously below air seal gas outlet 12 a. The air seal outlet 12a, the air seal air guide cavity 12c, the air seal air inlet 12b, the adjusting bolt 12d and the air seal sealing ring 12e jointly form an air seal unit 12.
The connecting pipe 11 is adjustably connected with the sample containing pipe 13 through adjusting bolts 12d uniformly arranged on the periphery, and the adjusting bolts 12d extend along the axial direction of the connecting pipe 11 and the sample containing pipe 13; the middle part of the adjusting bolt 12d is polygonal, the upper part and the lower part are both provided with threads, and the middle part is rotated to drive the upper and lower screw rods to rotate to adjust the relative position of the connecting pipe 11 and the sample containing pipe 13, so that the size of the air seal air outlet 12a is adjusted. In this embodiment, adjusting bolt 12d circumference equipartition is four, and every adjusting bolt 12d all corresponds the setting in an atmoseal inlet port 12b top, can cooperate adjusting bolt 12d position to carry out the atmoseal regulation, forms required atmoseal.
The blowback unit 15 is arranged between the sample loading pipe 13 and the optical detection window 14, and removes the coal dust on the optical detection window 14 through blowback. The blowback unit 15 includes a blowback chamber 151 and a plurality of blowback air inlets 152.
As shown in fig. 2 to 7, the blowback cavity 151 is disposed around the bottom of the sample loading tube 13, is integrally formed with the sample loading tube 13, and has a multi-petal semi-ellipsoidal structure, so as to form a blowback space with an inner hollow portion communicated with the sample loading tube 13 and an outer periphery expanding toward the installation area of the optical detection window 14 (i.e., the blowback space is formed by excavating the multi-petal semi-ellipsoidal structure from the inner wall of the bottom of the sample loading tube 13 along the radial direction in a reverse direction). The semi-ellipsoidal structure 151a is not an elliptical shape having a half cross section, but a part of the semi-ellipsoidal structure 151a (an ellipsoidal cavity of about one quarter of an ellipsoid) remaining after being truncated at both the intersection with the loading tube 13 and the intersection with the neighboring semi-ellipsoid. In this embodiment, the blowback cavity 151 includes a six-lobe semi-ellipsoidal structure 151a, and the minimum inner diameter of the blowback cavity 151 is equal to the inner diameter of the sample loading tube 13 and the inner diameter of the connecting tube 11.
As shown in fig. 4 and 8, the first focal points of all the semi-ellipsoidal structures 151a are circumferentially and uniformly distributed on the peripheral installation region of the optical detection window 14, in this embodiment, six blowback air inlets 152 are provided, and each blowback air inlet 152 is located at the first focal point of one half of the semi-ellipsoidal structure 151 a. As shown in fig. 8 and 9, the second focal points are uniformly distributed in the middle detection area of the optical detection window 14 in the circumferential direction, and the second focal point of the semi-ellipsoidal structure 151a is located on the other side of the central point of the optical detection window relative to the first focal point. Due to the structure, after the blowback airflow introduced by the blowback air inlet 152 at the first focus enters the semi-ellipsoidal structure 151a, the airflows in all directions converge to the second focus, so that the optical detection window 14 is effectively swept to the maximum extent, and the pulverized coal on the optical detection window 14 after sampling detection is removed. The window is a coal quality detection area, so that the cleaning of the window is particularly critical, the window can be effectively cleaned by an ellipsoid chamber focusing purging method, and the detection precision is guaranteed.
As shown in fig. 4, the mounting cover 16 is disposed at the bottom of the blowback unit 15 for hermetically mounting the optical detection window 14, and includes an upper cover ring 161, a lower cover ring 162, and a plurality of fixing members 163. The upper cover ring 161 and the lower cover ring 162 clamp and fix the optical detection window 14 from the upper side and the lower side in a sealing manner, and sealing rings are arranged at the contact positions of the edge of the optical detection window 14 and the upper cover ring 161 and the lower cover ring 162. One set of fasteners 163 is used to detachably fasten the upper cover ring 161 and the lower cover ring 162, and the other set of fasteners fastens the outer edge of the mounting cover 16 and the outer edge of the blowback unit 15; in this embodiment, the fixing element 163 is a screw fixing element. The bottom of the blowback air inlet 152 penetrates the mounting cover 16 and is connected with the external air inlet pipe.
The above is the specific structure of the online sampling device 10 for wind-powder pipe provided in this embodiment, and further, this embodiment also provides a method for performing automated online detection by using the online sampling device 10 for wind-powder pipe, specifically, the following operations are performed by the control part:
when the sampling is not carried out, the air seal air inlet valve on the air seal air inlet hole 12b externally connected with the air inlet pipe is in an open state, air flow with the air flow pressure of 0.3-0.7 MPa is continuously led in, an upward positive pressure air seal is formed at the connecting pipe 11, and the coal dust of the air dust pipe F is prevented from falling into the sample containing pipe 13.
Before sampling, a blowback air inlet valve on the external air inlet pipe of the blowback air inlet 152 is opened for multiple times (3-5 times), a large blowback air flow with the pressure of 0.5-0.7 MPa (0.7 MPa is adopted in the embodiment) is introduced, the duration is 2-5 s every time, the interval is 3s, and the optical detection window 14 is cleaned before sampling.
During sampling, the air seal air inlet valve of the air seal unit 12 is closed, so that the back flushing air inlet valve on the back flushing air inlet 152 externally connected with the air inlet pipe is kept in a closed state, the coal dust rapidly falls down, deposits on the optical detection window 14 and rapidly accumulates to cover the optical detection window 14 (the sample loading pipe 13 is also rapidly filled with the coal dust), and then the laser detection equipment emits a light beam to rapidly detect the coal dust through the optical detection window 14 to obtain optical detection data.
After detection is finished, an air seal air inlet valve of an air seal unit 12 is opened to introduce 0.5-0.7 MPa of air flow, an upward positive pressure air seal is formed at a connecting pipe 11 to prevent coal dust from falling from an air powder pipe F, and correspondingly, a negative pressure is formed at a sample loading pipe 13 below the air seal, so that the coal dust at the sample loading pipe 13, a back blowing cavity 151 and an optical detection window 14 is upwards coiled and sucked and then blown back to the air powder pipe F, pre-clearing of the coal dust in previous sampling detection is realized, most of the coal dust is returned to the air powder pipe F, and certain residual coal dust is still attached to the surface of the optical detection window 14. Then, a blowback air inlet valve of a blowback air inlet 152 is opened to introduce blowback air flow of 0.3MPa of small air pressure for continuous blowing, and the pulverized coal remained on the optical detection window 14 is blown to be sucked back to the pulverized coal pipe F (the blowback air pressure is relatively small, on one hand, the pulverized coal in the blowback cavity 151 is effectively blown up by blowback, so that the pulverized coal in the cavity is accelerated to return to the pulverized coal pipe F, the retention time of the pulverized coal in the cavity is reduced, on the other hand, the smaller pressure is also used, so that the pulverized coal partially close to the optical detection window 14 is prevented from being pressed tightly on a window due to overlarge air pressure, and the subsequent cleaning difficulty is increased).
After the detection is finished and the blowback air inlet 152 is opened for continuous blowing for a period of time (30-60s), intermittently introducing blowback air flow for blowback so as to disturb the pressure and flow velocity distribution in the blowback cavity 151, thereby cleaning up the residual coal powder: regulating the pressure of the back-blowing airflow to 0.3MPa, opening a back-blowing air inlet valve for back-blowing for 15s, closing for 5s, and repeating for 3 times; adjusting the pressure regulating valve to 0.5MPa, opening a back-blowing air inlet valve for back blowing for 10s, closing for 10s, and repeating for 3 times; and adjusting the pressure regulating valve to 0.7MPa, opening a back-blowing air inlet valve for back blowing for 5s, closing for 15s, and repeating for 3 times. The principle is that the low-pressure purging time is long, the interval is short, and the atmospheric purging time period is long; the pressure is small and large, when the residual coal dust is more, the residual coal dust is blown back through small pressure airflow for a relatively long time, the residual coal dust can be well removed, meanwhile, the pressure adhesion of the coal dust close to the optical detection window 14 is effectively avoided, when the residual coal dust is less, the atmospheric pressure short back blowing is adopted, the pressure of the cavity can be quickly disturbed, the coal dust is enabled to be separated from the optical detection window 14 and the cavity, the negative pressure suction of the air seal is matched, the residual coal dust adhered to the optical detection window 14 can be effectively removed through higher air pressure, and the short back blowing time under the higher air pressure can also avoid the coal dust from being tightly adhered to the optical detection window 14.
In the process of executing the operation by adopting the control part, the sampling frequency can be controlled by regulating and controlling the formation of the air seal, and the sampling representativeness can be ensured by regulating the back flushing, so that the influence of the previous sampling coal powder on the detection is avoided, and the accuracy of the detection result is ensured.
The above is merely an illustration of the technical solution of the present invention. The online sampling device and method for the wind powder tube F suitable for the optical detection technology in the present invention are not limited to the above-described structure, but are subject to the scope defined by the claims. Any modification or supplement or equivalent replacement made by the person skilled in the art on the basis of the present invention is within the scope of the claims of the present invention.
Claims (10)
1. The utility model provides an online sampling device of wind powder pipe suitable for optical detection technique which characterized in that includes:
the connecting pipe is connected with the air powder pipe for conveying powder and is arranged below the air powder pipe;
the air outlet is arranged around the inner wall of the connecting pipe, and external air flow is led in through the air outlet to form positive pressure in the connecting pipe so as to prevent the powder from falling;
the sample loading pipe is arranged below the air sealing unit, is communicated with the connecting pipe, and contains the falling powder when the air sealing unit stops air guide;
the optical detection window is arranged below the sample loading pipe, and light beams of external optical detection equipment penetrate through the optical detection window so as to detect the powder on the optical detection window; and
the back flushing unit is arranged between the sample loading pipe and the optical detection window, and is used for clearing the powder on the optical detection window through back flushing, and comprises a back flushing cavity and a plurality of back flushing air inlets; the back-blowing cavity is arranged around the bottom of the sample loading pipe and is of a multi-petal semi-ellipsoidal structure, a back-blowing space is formed, the interior of the back-blowing space is hollow and communicated with the sample loading pipe, the periphery of the back-blowing space extends towards the mounting area of the optical detection window, first focuses of all the semi-ellipsoidal structures are circumferentially and uniformly distributed on the peripheral mounting area of the optical detection window, second focuses are circumferentially and uniformly distributed in the range of the optical detection window, and the second focuses of the semi-ellipsoidal structures are located on the other side, opposite to the first focuses, of the center point of the window; the back blowing air inlets are arranged on the peripheral installation area, and each back blowing air inlet is located at the first focus of one semi-ellipsoidal structure.
2. The online sampling device for wind-powder pipe suitable for optical detection technology as claimed in claim 1, further comprising:
installation lid, the setting is in blowback unit bottom is used for the sealed installation optical detection window includes: the fixing piece is used for hermetically clamping and fixing an upper cover ring and a lower cover ring of the optical detection window from the upper side and the lower side, and fixedly connecting the upper cover ring and the lower cover ring in a detachable mode;
wherein the bottom of the back flushing air inlet penetrates through the mounting cover.
3. The online sampling device for wind-powder tubes suitable for optical detection technology as claimed in claim 1, wherein:
the back flushing cavity comprises at least four semi-ellipsoidal structures, and the minimum inner diameter of the back flushing cavity is equal to the inner diameter of the sample loading pipe and the inner diameter of the connecting pipe.
4. The online sampling device for wind-powder tubes suitable for optical detection technology as claimed in claim 1, wherein:
wherein, the blowback chamber includes six semi-ellipsoidal structures.
5. The online sampling device for wind-powder tubes suitable for optical detection technology as claimed in claim 1, wherein:
the semi-ellipsoidal structure is not an ellipse with a half cross section, but a part of the semi-ellipsoidal structure left after being cut at the intersection of the semi-ellipsoidal structure and the sample containing tube and the intersection of the semi-ellipsoidal structure and the adjacent semi-ellipsoidal structure.
6. The online sampling device for wind-powder tubes suitable for optical detection technology as claimed in claim 1, wherein:
the bottom end of the connecting pipe is arranged at a certain distance from the upper end of the sample loading pipe, the bottom end of the connecting pipe extends downwards and outwards in an inclined manner, the upper end of the sample loading pipe also extends downwards and outwards in an inclined manner to jointly form a circle of conical annular air seal air outlets, a circle of air seal air guide cavity is further formed at the lower part of the outer side of the upper end of the sample loading pipe, and at least two air seal air inlet holes are uniformly formed in the outer wall of the air seal air guide cavity;
the connecting pipe is adjustably connected with the sample loading pipe through adjusting bolts uniformly arranged on the periphery, and the adjusting bolts extend along the axial direction of the connecting pipe and the sample loading pipe; the middle part of the adjusting bolt is polygonal, the upper part and the lower part of the adjusting bolt are provided with threads, and the middle part is rotated to drive the screw rods of the upper part and the lower part to rotate to adjust the relative position of the adjusting connecting pipe and the sample loading pipe, so that the size of the gas seal gas outlet is adjusted;
the air seal air outlet, the air seal air guide cavity and the air seal air inlet hole jointly form the air seal unit.
7. An online sampling method for an air powder pipe suitable for an optical detection technology, which adopts the online sampling device for the air powder pipe of any one of claims 1 to 6 to perform sampling, and is characterized in that:
when the sampling is not carried out, the air seal unit is adopted to continuously introduce air flow to form air seal, so that powder of the air powder pipe is prevented from falling into the sample loading pipe;
during sampling, the air sealing unit stops air inlet, keeps the back-blowing air inlet closed, quickly drops powder, deposits on the optical detection window, and then detects the powder through the optical detection window by using an optical detection technology;
after the detection is finished, the air seal unit is adopted to introduce air flow, negative pressure is formed at the sample loading pipe, most of powder in the sample loading pipe is sucked back to the air powder pipe in a rolling mode, the back blowing air inlet is opened to introduce back blowing air flow with small air pressure, and the powder remained on the optical detection window is blown up to be sucked back to the air powder pipe in a rolling mode.
8. The online sampling method for the wind powder pipe suitable for the optical detection technology as claimed in claim 7, wherein:
before sampling, a back-blowing air flow is introduced from a back-blowing air inlet for multiple times, and an optical detection window is cleaned before sampling;
and after the detection is finished and the back-blowing air inlet is opened for continuous purging for a period of time, back-blowing airflow is intermittently introduced for back blowing.
9. The online sampling method for the wind powder pipe suitable for the optical detection technology as claimed in claim 8, wherein:
the specific operation method for intermittently introducing the back-blowing airflow for back-blowing comprises the following steps: setting the air pressure of the blowback air flow to be P1, opening blowback for a certain time t1, closing for a plurality of seconds, and repeating for a plurality of times; regulating the pressure regulating valve to P2, opening the back flushing for a certain time t2, closing for a plurality of seconds, and repeating for a plurality of times; regulating the pressure regulating valve to P3, opening the back flushing valve for a certain time t3, closing for several seconds, and repeating for several times; p1 < P2 < P3, t1 > (t2+3s) > (t3+3 s).
10. The online sampling method for the wind powder pipe suitable for the optical detection technology as claimed in claim 7, wherein:
wherein, the control part is adopted to control the air inlet valve of the air seal unit to open and continuously introduce airflow when the sampling is not carried out, so as to form an air seal; the control part is adopted to control an air inlet valve of the back-blowing air inlet to be opened for multiple times before sampling so as to introduce back-blowing air flow and clean a back-blowing cavity and an optical detection window; the control part is adopted to control the closing of the air inlet valve of the air sealing unit and the closing of the air inlet valve of the back flushing air inlet during sampling so that the powder material quickly falls down and is deposited on the optical detection window, and then the optical detector is controlled to detect the powder material through the optical detection window; and the control part is adopted to control the air inlet valve of the air sealing unit to be opened after detection is finished, negative pressure is formed at the sample loading pipe, most of powder in the sample loading pipe is sucked back to the air powder pipe in a rolling mode, then the air inlet valve of the back blowing air inlet is controlled to be opened to introduce back blowing airflow of small air pressure, and powder remained on the optical detection window is removed.
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| CN202210091399.3A CN114459829B (en) | 2022-01-26 | 2022-01-26 | Online sampling device and method for air-powder tube suitable for optical detection technology |
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