A sampling device for preventing smoke particles from being adsorbed

Abstract

The present invention discloses a sampling device for preventing smoke and dust particles from being adsorbed, and belongs to the technical field of particle sampling. It comprises: a metal sampling tube group, comprising a first sampling tube, a second sampling tube, a third sampling tube and a fourth sampling tube connected in sequence; wherein the distal end of the first sampling tube extends into the flue to be detected, and the proximal end of the fourth sampling tube is connected to a particle measurement module; an electrostatic generating device, comprising a main unit and a first electrostatic output end, a second electrostatic output end and a third electrostatic output end, wherein the first electrostatic output end has the same polarity as the second electrostatic output end, and the first electrostatic output end has an opposite polarity to the third electrostatic output end, the first electrostatic output end extends into the second sampling tube, the second electrostatic output end is electrically connected to the third sampling tube; and the third electrostatic output end extends into the fourth sampling tube. The present invention solves the problem that particles in existing sampling devices are easily adsorbed on the tube wall, resulting in poor measurement accuracy.

Description

Technical Field

[0001] The invention relates to the field of fixed pollution source sampling, and in particular to a sampling device for preventing smoke and dust particles from being adsorbed. Background Art

[0002] With the improvement of the domestic environment, the concentration of smoke particles, especially the concentration of particles in fixed pollution sources, is getting lower and lower, and many enterprises have already achieved ultra-low emissions. At this time, the detection of the concentration of particles emitted by enterprises has put forward higher requirements for detection methods. The commonly used detection methods at present are the weight method and the β-ray direct reading method. The weight method has a relatively complicated process, which requires repeated drying and weighing, and the detection cycle is long. The β-ray direct reading method can read the concentration of particles on site, and it has received more and more attention. This method is to insert the sampling tube into the sampling port of the flue, and there is a β-ray concentration measuring device and a vacuum pump at the rear end of the sampling tube. The vacuum pump extracts the sample gas at the front end of the sampling tube, and the sampling tube enters the β-ray concentration measuring device to detect the concentration of particles.

[0003] At present, when the beta-ray concentration measuring device is used for air extraction, some particles will be adsorbed on the inner wall of the sampling tube when the sample gas passes through the sampling tube, which will cause the back-end beta-ray concentration measuring device to receive fewer particles, resulting in the particle concentration measurement value being lower than the actual value. Especially now that most emissions are low-concentration, or even ultra-low-concentration emissions, slight adsorption will also cause a large deviation in the particle concentration measurement value; for the problem of particle adsorption sampling tubes, metal tubes with smoother inner walls are currently used to improve it, but this method cannot solve the problem completely. Summary of the invention

[0004] The technical problem to be solved by the present invention is that in the existing beta-ray concentration measuring device, some particles are adsorbed on the inner wall of the sampling tube, resulting in poor measurement accuracy.

[0005] In view of the above technical problems, the present invention provides the following technical solutions:

[0006] The present invention provides a sampling device for preventing smoke and dust particles from being adsorbed, comprising: a metal sampling tube group, comprising a first sampling tube, a second sampling tube, a third sampling tube and a fourth sampling tube connected in sequence; wherein the distal end of the first sampling tube extends into a smoke duct to be detected, the proximal end of the fourth sampling tube is connected to a particle measurement module, and the length of the third sampling tube is greater than the length of any one of the first sampling tube, the second sampling tube and the fourth sampling tube; an electrostatic generating device, comprising a main unit and a first electrostatic output end, a second electrostatic output end and a third electrostatic output end, wherein the first electrostatic output end has the same polarity as the second electrostatic output end, and the first electrostatic output end has an opposite polarity to the third electrostatic output end, and the first electrostatic output end extends into the second sampling tube to convert the particles in the second sampling tube into charged particles with a first polarity; the second electrostatic output end is electrically connected to the third sampling tube; the third electrostatic output end extends into the fourth sampling tube to neutralize the charged particles with the first polarity to eliminate the charge of the particles.

[0007] In some embodiments of the present invention, a ceramic tube is provided in the second sampling tube, a first corona electrode is provided in the ceramic tube, the first corona electrode is connected to the first electrostatic output end, the first corona electrode is located in the center of the ceramic tube and extends along the length direction of the ceramic tube.

[0008] In some embodiments of the present invention, a second corona electrode is disposed in the fourth sampling tube, the second corona electrode is connected to the third electrostatic output end, and the second corona electrode is located at the center of the fourth sampling tube and extends along the length direction of the fourth sampling tube.

[0009] In some implementation modes of the present invention, the corona inception voltage U of the first corona electrode 50 and the second corona electrode 60 is obtained by the following formula:

[0010]

[0011] Among them, R1 is the radius of the corona electrode; R2 is the radius of the sampling tube; m is the surface roughness coefficient of the corona electrode; ρ is the air density under working conditions.

[0012] In some implementation modes of the present invention, the corona inception voltage of the first corona electrode is the same as the corona inception voltage of the second corona electrode, and the first corona electrode and the second corona electrode have the same length.

[0013] In some embodiments of the present invention, the length of the first corona electrode is the same as that of the second sampling tube, and the second corona electrode extends from the distal end of the fourth sampling tube to 1 / 2 of the fourth sampling tube.

[0014] In some embodiments of the present invention, a protective sleeve is further included which is sleeved on the outside of the metal sampling tube group. An insulating gap is provided between the protective sleeve and the metal sampling tube group and the protective sleeve and the metal sampling tube group are isolated by at least one insulating member.

[0015] In some embodiments of the present invention, the protective sleeve is located in the outer area where the first sampling tube, the second sampling tube, and the third sampling tube are located, and a first insulating member and a second insulating member are arranged between the protective sleeve and the first sampling tube, the second sampling tube, and the third sampling tube. The first insulating member is located on a side of the second sampling tube close to the first sampling tube, and the second insulating member is located on a side of the third sampling tube close to the fourth sampling tube.

[0016] In some embodiments of the present invention, the insulating gap between the first insulating member and the second insulating member is filled with insulating liquid.

[0017] In some embodiments of the present invention, an ultrasonic vibration generating device is further included, and an output end of the ultrasonic vibration generating device acts on a position of the protective sleeve close to the third sampling tube.

[0018] The technical solution of the present invention has the following technical effects compared with the prior art:

[0019] In the sampling device for preventing adsorption of smoke particles provided by the present invention, the particles in the sampling tube are combined with electrons generated by air ionization at the distal side of the metal sampling tube group to form charged particles, and at the same time, the longer third sampling tube is charged so that its polarity is the same as that of the charged particles. When the particles pass through the third sampling tube, due to the mutual repulsion of like charges, the particles will not be adsorbed on the tube wall of the sampling tube, thereby greatly improving the measurement accuracy of the sampling device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, which will help to understand the objects and advantages of the present invention, wherein:

[0021] Figure 1 A schematic structural diagram of a specific embodiment of a sampling device for preventing smoke and dust particle adsorption according to the present invention;

[0022] Figure 2 A partial enlarged view of a specific embodiment of the sampling device for preventing smoke and dust particles from being adsorbed according to the present invention;

[0023] Figure 3 Another partially enlarged view of a specific embodiment of the sampling device for preventing smoke particles from being adsorbed according to the present invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] Reference Figure 1-3 The figure shows a specific embodiment of the sampling device for preventing smoke particles from being adsorbed (hereinafter referred to as the sampling device) of the present invention, which is used to extend into the flue to be detected to obtain particles in the flue and transport the particles along the flue to the particle measurement module. The sampling device includes a metal sampling tube group of a slender tube structure. For the convenience of description, in the present invention, the side of each part of the sampling device close to the particle measurement module is defined as the proximal end, and the side close to the flue is defined as the distal end.

[0029] The sampling device includes a metal sampling tube group, including a first sampling tube 11, a second sampling tube 12, a third sampling tube 13 and a fourth sampling tube 14 connected in sequence; wherein the distal end of the first sampling tube 11 extends into the flue to be detected, and the first sampling tube 11 and the second sampling tube 12 are insulated and connected by a first insulating member 31; the second sampling tube 12 is directly connected to the third sampling tube 13 or insulated and connected by an insulating member, the third sampling tube 13 and the fourth sampling tube 14 are insulated and connected by a second insulating member 32, and the proximal end of the fourth sampling tube 14 is connected to the particle measurement module 100, wherein the length of the third sampling tube 13 is much greater than the length of any one of the first sampling tube 11, the second sampling tube 12 and the fourth sampling tube 14; specifically, the length of the first sampling tube 11 is 50 mm-150 mm, the length of the second sampling tube 12 is 30 mm-60 mm, the length of the third sampling tube 13 is 1000 mm-1500 mm, and the length of the fourth sampling tube 14 is 60 mm-150 mm. It can be seen that since the length of the third sampling tube 13 accounts for more than 90% of the total length of the metal tube group, which is much longer than the lengths of other sampling tubes, preventing particles from being adsorbed on the third sampling tube 13 can greatly improve the detection accuracy of the sampling device.

[0030] The sampling device also includes an electrostatic generating device 20, which includes a main unit and a first electrostatic output terminal 21, a second electrostatic output terminal 22 and a third electrostatic output terminal 23, wherein the first electrostatic output terminal 21 and the second electrostatic output terminal 22 have the same polarity, and the first electrostatic output terminal 21 and the third electrostatic output terminal 23 have opposite polarities, and the first electrostatic output terminal 21 extends into the second sampling tube 12 to convert the particles in the second sampling tube 12 into charged particles with a first polarity; the second electrostatic output terminal 22 is electrically connected to the third sampling tube 13; and the third electrostatic output terminal 23 extends into the fourth sampling tube 14 to neutralize the charged particles with the first polarity to eliminate the charge of the particles.

[0031] In this way, after the particles enter the metal sampling tube group through the distal end port of the first sampling tube 11, they pass through the second sampling tube 12 and combine with the electrons generated by the ionized air to form charged particles with a first polarity, such as negatively charged particles; when passing through the third sampling tube 13, since the third sampling tube 13 is connected to the second electrostatic output end 22, the charged particles will not be adsorbed on the third sampling tube 13 due to the repulsion of like charges. When the negatively charged particles pass through the third sampling tube 13 and reach the fourth sampling tube 14, the negatively charged particles are neutralized with the positive ions in the air, eliminating the charge combined with the particles. Finally, the uncharged particles enter the particle measurement module 100 (such as the β-ray particle concentration measurement module) for subsequent measurement.

[0032] The sampling device introduces an electrostatic generator 20 to generate like charges in the longer sampling tube and the particles in the sampling tube. Due to the mutual repulsion of like charges, the particles are prevented from being adsorbed on the tube wall, which greatly improves the measurement accuracy of the sampling device.

[0033] In an optional embodiment, the second sampling tube 12 and the third sampling tube 13 are directly integrated into an independent tube body, wherein a ceramic tube 40 is provided in the second sampling tube 12, a first corona electrode 50 is provided in the ceramic tube 40, the first corona electrode 50 is connected to the first electrostatic output end 21, and the first corona electrode 50 is located at the center of the ceramic tube 40 and extends along the length direction of the ceramic tube 40. Since the ceramic tube 40 is an insulating tube, the first corona electrode 50 to which high voltage is applied ionizes the air, and the charged ions generated will not charge the ceramic tube. Therefore, when the particles to be measured pass through, they will not be attracted by the ceramic tube, but will directly combine with the charges near the first corona electrode 50 to form charged particles, and then enter the third sampling tube 13.

[0034] More specifically, the length of the first corona electrode 50 is the same as the length of the second sampling tube 12 , so that the particulate matter can be fully ionized in the second sampling tube 12 .

[0035] Control the static electricity generating device 20 to gradually apply high voltage to the first corona discharge electrode 50. When the voltage increases to a certain value U, the air near the first corona discharge electrode 50 is ionized to produce positive ions and electrons. The positive ions are rapidly absorbed by the first corona discharge electrode 50 connected to negative electricity, while the electrons with negative charge are excluded and are trapped in the air. The electrons trapped in the air are surrounded by a circle centered on the first corona discharge electrode 50, and the circle diameter is d1. The larger the voltage, the larger the diameter d1. When the voltage U1 is continued to be increased to be greater than the corona initiation voltage U, the scope of air ionization is gradually expanded, so that the particulate matter is combined with the electrons trapped in the air to become negatively charged particles.

[0036] In an optional embodiment, a second corona electrode 60 is provided in the fourth sampling tube 14, the second corona electrode 60 is connected to the third electrostatic output terminal 23, and the second corona electrode 60 is located at the center of the fourth sampling tube 14 and extends along the length direction of the fourth sampling tube 14. More specifically, the second corona electrode 60 extends from the distal end of the fourth sampling tube 14 to 1 / 2 of the fourth sampling tube 14.

[0037] Wherein, the corona inception voltage U of the first corona electrode 50 and the second corona electrode 60 is obtained by the following formula:

[0038]

[0039] Among them, R1 is the radius of the corona electrode (the corona electrode is the first corona electrode or the second corona electrode); R2 is the radius of the sampling tube (the sampling tube is the ceramic tube corresponding to the first corona electrode or the fourth sampling tube corresponding to the second corona electrode); m is the surface roughness coefficient of the corona electrode; ρ is the air density under working conditions.

[0040] Among them, the air density ρ under working conditions is obtained by the following formula:

[0041]

[0042] ρ1, P1, T1 are the air density, atmospheric pressure and temperature under standard conditions; ρ1 is 1.293 kg / m 3 ; P1 is 1013 mbar; T1 is 273 K; where T and P are the temperature and pressure values ​​of the gas under operating conditions, measured by the operating condition measuring instrument.

[0043] The corona inception voltage U1 of the first corona electrode 50 is equal to the corona inception voltage U2 of the second corona electrode 60. Meanwhile, the lengths of the first corona electrode 50 and the second corona electrode 60 are equal. Through the above arrangement, on the one hand, the particulate matter can be fully ionized in the second sampling tube 12 section, and at the same time, the number of ions generated by the second sampling tube 12 and the fourth sampling tube 14 are basically the same, so that the charged particulate matter can be completely neutralized in the front section of the fourth sampling tube 14, and the charged particulate matter can be prevented from entering the particulate matter measurement module 100 as much as possible.

[0044] In an optional embodiment, a conductive wire is wound on the outer tube wall of the third sampling tube 13, and the conductive wire is connected to the second electrostatic output end 22; the conductive wire is evenly arranged on the tube wall of the third sampling tube 13, so that the charge carried by each part of the third sampling tube 13 is more uniform.

[0045] In order to protect the safety of the sampling personnel, the sampling device also includes a protective sleeve 70 which is sleeved on the outside of the metal sampling tube group. The protective sleeve 70 is an insulating sleeve, which can prevent the sampler from being damaged by static electricity during sampling. There is an insulating gap between the protective sleeve 70 and the metal sampling tube group and they are isolated by at least one insulating part.

[0046] In an optional embodiment, the protective sleeve 70 is located in the outer area where the first sampling tube 11, the second sampling tube 12, and the third sampling tube 13 are located, and the protective sleeve 70 is insulated and isolated from the first sampling tube 11, the second sampling tube 12, and the third sampling tube 13 by the first insulating member 31 and the second insulating member 32; wherein, the first insulating member 31, on the one hand, isolates the protective sleeve 70 and the first sampling tube 11 from the second sampling tube 12, and at the same time realizes the insulated connection between the first sampling tube 11 and the second sampling tube 12, and the second insulating member 32, on the one hand, isolates the protective sleeve 70 and the third sampling tube 13 from the fourth sampling tube 14, and at the same time realizes the insulated connection between the third sampling tube 13 and the fourth sampling tube 14.

[0047] In order to further prevent particles from being adsorbed on the wall of the sampling tube, the sampling device also includes an ultrasonic vibration generating device 80, which acts on the position of the protective sleeve 70 close to the third sampling tube 13. The high-frequency vibration of the ultrasonic vibration generating device 80 is used to peel off a very small amount of particles adsorbed on the inner wall of the sampling tube, thereby improving the accuracy of particle concentration detection. Since the third sampling tube 13 is relatively long, some large particles may be adsorbed on the proximal side of the third sampling tube 13. Therefore, the output end of the ultrasonic vibration generating device 80 is located close to the proximal side of the third sampling tube 13.

[0048] In order to make the ultrasonic vibration propagation more uniform, the insulating gap between the protective sleeve 70 and the metal sampling tube group is filled with insulating liquid 90 at a position between the first insulating member 31 and the second insulating member 32. For example, it is filled with electronic fluoride liquid. In this way, the high-frequency vibration force penetrating the electronic fluoride liquid can act evenly on the third sampling tube 13, the third sampling tube 13 is subjected to more uniform force, and the particles adsorbed on the inner wall of the sampling tube are more efficiently peeled off.

[0049] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A sampling device for preventing smoke particles from being adsorbed, characterized in that: include: A metal sampling tube set, comprising a first sampling tube, a second sampling tube, a third sampling tube and a fourth sampling tube connected in sequence; wherein the distal end of the first sampling tube extends into the flue to be detected, the proximal end of the fourth sampling tube is connected to the particle measurement module, and the length of the third sampling tube is greater than the length of any one of the first sampling tube, the second sampling tube and the fourth sampling tube; The electrostatic generating device comprises a main unit and a first electrostatic output terminal, a second electrostatic output terminal and a third electrostatic output terminal, wherein the first electrostatic output terminal and the second electrostatic output terminal have the same polarity, and the first electrostatic output terminal and the third electrostatic output terminal have opposite polarities, and the first electrostatic output terminal extends into the second sampling tube to convert the particles in the second sampling tube into charged particles with a first polarity; the second electrostatic output terminal is electrically connected to the third sampling tube; the third electrostatic output terminal extends into the fourth sampling tube to neutralize the charged particles with a first polarity to eliminate the charge of the particles; A ceramic tube is arranged in the second sampling tube, a first corona electrode is arranged in the ceramic tube, the first corona electrode is connected to the first electrostatic output end, the first corona electrode is located at the center of the ceramic tube and extends along the length direction of the ceramic tube; It also includes a protective sleeve sleeved on the outside of the metal sampling tube group, wherein the protective sleeve is isolated from the first sampling tube and the second sampling tube by a first insulating member, and the protective sleeve is isolated from the third sampling tube and the fourth sampling tube by a second insulating member; the insulating gap between the first insulating member and the second insulating member is filled with insulating liquid; It also includes an ultrasonic vibration generating device, the output end of which acts on the proximal end side of the protective sleeve close to the third sampling tube; A second corona electrode is arranged in the fourth sampling tube, the second corona electrode is connected to the third electrostatic output end, and the second corona electrode is located at the center of the fourth sampling tube and extends along the length direction of the fourth sampling tube.

2. A sampling device for preventing smoke particles from being adsorbed according to claim 1, characterized in that: The corona inception voltage U of the first corona electrode and the second corona electrode is obtained by the following formula: Among them, R1 is the radius of the corona electrode; R2 is the radius of the sampling tube; m is the surface roughness coefficient of the corona electrode; ρ is the air density under working conditions.

3. A sampling device for preventing smoke particles from being adsorbed according to claim 1, characterized in that: The corona inception voltage of the first corona electrode is the same as the corona inception voltage of the second corona electrode, and the first corona electrode is the same as the second corona electrode in length.

4. A sampling device for preventing smoke particles from being adsorbed according to claim 2, characterized in that: The length of the first corona electrode is the same as that of the second sampling tube, and the second corona electrode extends from the distal end of the fourth sampling tube to 1 / 2 of the fourth sampling tube.

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