CN111366513A - An air curtain protection device for laser scattering detection of particulate matter - Google Patents

Abstract

The invention discloses an air curtain protection device for detecting particulate matter by laser scattering, which includes an air chamber on which a sample gas inlet and a sample gas outlet are arranged; a laser, which is located on one side of the air chamber; and a receiver, which is located in the air chamber. The other side of the air chamber; wherein, the laser and the receiver are connected to the air chamber sequentially through a protective mirror and an air curtain chamber; the air curtain chamber is a conical air curtain chamber, and the air curtain is outside the An air inlet is provided, and the gas entering from the air inlet forms two rotating air curtains with opposite movement directions in the air curtain chamber. In the present invention, the protective gas forms a three-dimensional air curtain with two moving directions in the air curtain cavity, which can effectively isolate the sample gas to be tested and the protective gas, and at the same time, the spiral airflow can also clean the protective lens and prolong the maintenance period of the protective lens. The operating cost of the instrument.

Description

An air curtain protection device for laser scattering detection of particulate matter

technical field

The invention relates to the field of environmental monitoring, including oil fume monitoring, dust monitoring, smoke monitoring, etc., in particular to an air curtain protection device for detecting particulate matter by laser scattering.

Background technique

Existing dust measurement equipment usually uses a laser sensor as the core equipment. The gas to be measured enters the laser sensor, and the laser emits laser light through the sampling gas. The photosensitive tube on the opposite side receives the light intensity and generates an electrical signal, which is then processed by the amplifying circuit and CPU to obtain a readable signal for output and obtain the measurement value. If no protective measures (protective blowing) are taken, it will be very easy for the optical components in the laser to contact the suspended matter. When the contamination falls on the surface of the lens, it will absorb energy from the laser beam. On the one hand, the output power of the laser will be reduced, making the laser The processing ability drops sharply; on the other hand, heat is generated, which will cause damage to the lens itself and the optical coating on the surface over time.

The existing patent CN208408890U discloses an air curtain protection device for a laser working head, including an inner nozzle and an outer nozzle, the inner nozzle and the outer nozzle are in interference fit, the inner nozzle is connected with the laser working head, and the outer nozzle is provided with There is a gas inlet, the gas inlet is connected with the air compressor through a gas pipe, an annular cavity is arranged between the inner nozzle and the outer nozzle, the annular cavity is communicated with the gas inlet, and the annular cavity is provided with a gas outlet, the gas The outlet includes an air outlet provided on the inner nozzle and an annular air outlet at the bottom of the annular cavity, and the annular air outlet is formed by the gap left at the connection between the inner nozzle and the bottom of the outer nozzle. The existing patent CN105397287A discloses a dust removal device for a carbon dioxide laser drilling machine, which includes: a casing surrounding the laser and the periphery of the worktable; a first air supply unit for forming a turbulent state; a second air supply unit installed on the side wall of the housing for spraying an air curtain to the lens of the laser; and a second air supply unit installed outside the housing for blowing the an exhaust unit for sucking out the smoke and debris left by processing in the enclosure; wherein the first air supply unit and the exhaust unit are communicated with the hollow cavity of the enclosure, and the exhaust unit is arranged at the lower part of the casing.

To sum up, the existing air curtain protection solutions all form a small slit of 0.2-0.4 mm in front of the lens. On the one hand, the air curtain formed after the gas is blown out through the slit is a surface. This air curtain structure can only passively protect the lens, but cannot actively clean the lens and prevent particles from entering the laser air chamber; on the other hand, this slit structure requires extremely high processing and installation accuracy. Once deviation occurs, it will affect the Subsequent detection accuracy. Therefore, there is a need for an air curtain protection device for detecting particulate matter by laser light scattering, so as to improve the deficiencies in the prior art.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems in the prior art, the present invention provides an air curtain protection device for laser scattering detection of particulate matter, which has a simple structure, saves parts cost, simple assembly operation, improves assembly quality, prolongs the maintenance and cleaning period of the protective lens, and saves money. The operating cost of the testing instrument.

To achieve the above object, the present invention adopts the following technical solutions:

An air curtain protection device for detecting particulate matter by laser scattering, comprising:

A gas chamber, on which a sample gas inlet and a sample gas outlet are arranged;

a laser located on one side of the gas chamber;

a receiver located on the other side of the air chamber;

Wherein, the laser and the receiver are connected to the air chamber through a protective mirror and an air curtain chamber in sequence; the air curtain chamber is a conical air curtain chamber, and an air inlet is arranged outside the air curtain, The gas entering the air inlet forms two kinds of rotating air curtains with opposite moving directions in the air curtain chamber.

In some embodiments of the present invention, the included angle between the air inlet and the tangent of the air inlet on the inner wall of the air curtain is an obtuse angle.

In some embodiments of the present invention, the obtuse angle is in the range of 100-120°.

In some embodiments of the present invention, the area of the cross-section of the air curtain cavity gradually decreases in the direction close to the air chamber.

In some embodiments of the present invention, the air inlet is tangent to the inner wall of the air curtain cavity.

In some embodiments of the present invention, the two types of rotating air curtains include a cleaning air curtain that moves toward the protective mirror and an isolation air curtain that moves toward the air chamber.

In some embodiments of the present invention, the air curtain protection device further includes an air pump, and the air pump is arranged at the sample gas outlet to form a negative pressure in the air chamber to facilitate the discharge of the sample gas.

In some embodiments of the present invention, the air curtain protection device further includes an optical trap, the optical trap and the laser are disposed opposite the air chamber, and the optical trap is located above the receiver.

In some embodiments of the present invention, the light-emitting direction of the laser and the light-emitting direction of the receiver form an included angle a, where the included angle a is in the range of 10°<a<20°.

The working principle of the present invention is:

The air curtain room is filled with protective gas with a certain air pressure, and the protective gas enters the air curtain room through the air inlet to form a spiral air flow with two moving directions, that is, a rotating air curtain; under the action of the negative pressure of the air pump, part of the air curtain is isolated. Spiral movement directly toward the air chamber to prevent the sample gas from entering the air curtain chamber; the other part is the cleaning air curtain, which spirally moves toward the protective lens in the opposite direction to produce a cleaning effect; after reaching the protective lens, the same negative pressure of the air pump is applied. Under the action of the cleaning air curtain will eventually enter the air chamber.

The technical solution of the present invention has the following technical effects relative to the prior art:

1. In the present invention, a conical air curtain cavity is adopted, and the protective gas forms a rotating air curtain with two moving directions in the air curtain cavity, which can effectively isolate the sample gas to be tested and the protective gas, and at the same time, the rotating airflow can also clean the protective lens , Extend the maintenance cycle of the protective lens.

2. In the present invention, the receiver and the laser are not arranged on the same horizontal line, but are arranged at a certain angle, and the focal point of the light-emitting direction and the light-sensing direction is located on the connection line between the air inlet and the air outlet of the sample gas to be tested, Make the detection data more accurate.

3. The air curtain protection device used in the present invention has a simple structure, saves the cost of parts, and is easy to assemble. It can effectively improve the assembly quality, and can achieve a better protection effect than the previous scheme, prolong the maintenance and cleaning cycle of the lens, save money The operating cost of the testing instrument.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of an air curtain protection device for detecting particulate matter by laser light scattering in Example 1. FIG.

FIG. 2 is a schematic cross-sectional view of A-A in FIG. 1 .

FIG. 3 is a schematic cross-sectional view of B-B in FIG. 2 .

FIG. 4 is a schematic diagram of the airflow in the first air curtain chamber described in Example 1. FIG.

FIG. 5 is a schematic axial view of the structure of the air curtain protection device for detecting particulate matter by laser light scattering in Example 1. FIG.

Reference numerals: 1-laser; 2-gas chamber; 3-receiver; 4-sample gas inlet; 5-sample gas outlet; 6-first gas curtain chamber; 61-first joint; 62-first inlet 7-the second air curtain chamber; 71-the second joint; 72-the second air inlet; 8-light trap; 9-the first protection lens; 10-the second protection lens.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection connected, or integrally connected. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations. In the foregoing description of the embodiments, the particular features, structures, materials or characteristics may be combined in any suitable manner in any one or more of the embodiments or examples.

Example 1

As shown in Figures 1 and 2, an air curtain protection device for laser scattering detection of particulate matter includes a laser 1, an air chamber 2, a receiver 3, a sample gas inlet 4, a sample gas outlet 5, a first air curtain chamber 6, a first Two air curtain chambers 7 , light traps 8 , first protective lenses 9 and second protective lenses 10 .

The upper surface and the lower surface of the air chamber 2 are respectively provided with a sample gas inlet 4 and a sample gas outlet 5; the sample gas outlet 5 is provided with an air pump (not shown in the figure), and the air pump is used to form a gas pump in the air chamber 2. Negative pressure facilitates the discharge of sample gas. For the laser 1, it is located on one side of the air chamber 2; it is connected to the air chamber 2 through the first protective lens 9 and the first air curtain chamber 6 in sequence. For the receiver 3, it is located on the other side of the air chamber 2; it is connected to the air chamber 2 through the second protective lens 10 and the second air curtain chamber 7 in sequence. The air curtain protection device also includes an optical trap 8, the optical trap 8 and the laser 1 are symmetrically arranged relative to the gas chamber 2, and the optical trap 8 is located above the receiver 3, that is, the optical trap. 8 and the laser 1 are arranged on the same horizontal line, which is convenient for receiving the laser light emitted by the laser 1. In this embodiment, the light-emitting direction of the laser 1 and the light-sensing direction of the receiver 3 form an included angle a, wherein the included angle a is 15°; the focal point of the light-emitting direction and the light-sensing direction is located between the sample gas inlet 4 and the sample gas The connection of outlet 5 makes the detection data more accurate, as shown in Figure 5.

For the first air curtain chamber 6 and the second air curtain chamber 7, the structures and components of both are exactly the same. The first air curtain chamber 6 is provided with a first joint 61 and a first air inlet 62; the first joint 61 is connected with the first air inlet 62, as shown in FIG. 3, the first air inlet 62 and The included angle between the tangent lines at the air inlet on the inner wall of the first air curtain chamber 6 is an obtuse angle. In the direction close to the air chamber 2, the cross-sectional area of the first air curtain chamber 6 gradually decreases, that is, a conical air curtain chamber is formed. The first air inlet 62 is tangent to the inner wall of the first air curtain chamber 6 . After the protective gas is connected to the first joint 61, it enters the first air curtain chamber 6 through the first air inlet 62, and the protective gas charged into the first air curtain chamber 6 has a certain air pressure, which can ensure that the protective gas is in the first air curtain chamber 6. There are two three-dimensional rotating dynamic air curtains in the curtain room 6; as shown in Figure 4, one is a clean air curtain that rotates clockwise and moves toward the first protective lens 9. The spiral motion of the clean air curtain can effectively The other is the isolation air curtain that rotates clockwise and moves toward the air chamber 2, which can prevent the sample gas from entering the first air curtain chamber 6; under the action of the air pump, the cleaning air curtain reaches the first air curtain A protective lens 9 then similarly enters the air chamber 2 in the form of a spiral air curtain. On one side of the receiver 3, the structure and installation position of the second air curtain chamber 7 are the same as those of the first air curtain chamber 6; similarly, the second air curtain chamber 7 is provided with a second joint 71 and a second air inlet 72; the second joint 71 is connected to the second air inlet 72; the included angle between the second air inlet 72 and the tangent at the air inlet on the inner wall of the second air curtain chamber 7 is an obtuse angle. In the direction close to the air chamber 2, the cross-sectional area of the second air curtain chamber 7 gradually decreases, that is, a conical air curtain chamber is formed. The second air inlet 72 is tangent to the inner wall of the second air curtain chamber 7 . After the protective gas is connected to the second joint 71, it enters the second air curtain chamber 7 through the second air inlet 72, and the protective gas charged into the second air curtain chamber 7 has a certain air pressure, which can ensure that the protective gas is in the second air curtain chamber 7. Two spiral airflows formed in the curtain chamber 7; one spiral airflow can clean the second protective lens 10 in real time, prolonging the maintenance cycle of the protective lens; the other spiral airflow moves to the air chamber 2, preventing the sample gas from entering the second air curtain The chamber 7 thus avoids contamination of the second protective lens 10 and the receiver 3 .

The working principle of the present invention is:

When the air pump is started and the sample gas enters the sample gas inlet 4, a protective gas with a certain air pressure is introduced into the first joint 61 and the second joint 71, and the protective gas enters through the first air inlet 62 and the second air inlet 72 The first air curtain chamber 6 and the second air curtain chamber 7, because the inner wall of each air curtain chamber is conical and the included angle between each air inlet and the tangent at the air inlet on the inner wall of the air curtain is an obtuse angle, This embodiment is preferably 100-120°, which can ensure that the rotating airflow in both directions has a certain strength, and the airflow in the two opposite directions rotates in the air curtain room to form a three-dimensional rotating air curtain. Under the action of negative pressure, it spirals directly toward the air chamber 2 to prevent the sample gas from entering the first air curtain chamber 6 and the second air curtain chamber 7; The second protective lens 10 moves in a spiral to produce a cleaning effect; after reaching each protective lens, the cleaning air curtain will also enter the air chamber 2 eventually under the action of the negative pressure of the air pump. The air curtain protection device adopted in the present invention has a simple structure, saves the cost of parts, and is simple in assembly operation, which can effectively improve the assembly quality, and can achieve a better protection effect than the previous scheme, prolong the maintenance and cleaning cycle of the lens, and save the detection instrument. operating costs.

In the foregoing description of the embodiments, the particular features, structures, materials or characteristics may be combined in any suitable manner in any one or more of the embodiments or examples.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered. within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (9)

1. An air curtain protection device for detecting particles through laser scattering is characterized by comprising

The gas chamber is provided with a sample gas inlet and a sample gas outlet;

a laser located on one side of the gas cell;

a receiver located at the other side of the gas chamber;

the laser and the receiver are connected with the air chamber sequentially through a protective lens and an air curtain chamber; the air curtain chamber is the toper air curtain chamber, the air curtain chamber sets up the air inlet outward, follows the gas that the air inlet got into is in the indoor two kinds of rotatory air curtains that form the opposite direction of motion of air curtain.

2. The air curtain protection device for detecting the particles through laser scattering of claim 1, wherein an included angle between the air inlet and a tangent line at the air inlet on the inner wall of the air curtain chamber is an obtuse angle.

3. The gas curtain protection device for detecting particles through laser scattering as claimed in claim 2, wherein the obtuse angle ranges from 100 ° to 120 °.

4. The gas curtain protection device for the laser scattering detection of particles as claimed in claim 2, wherein the cross-sectional area of the gas curtain cavity decreases gradually in the direction close to the gas chamber.

5. The gas curtain protection device for the laser scattering detection of particles as claimed in claim 1, wherein the gas inlet is tangential to the inner wall of the gas curtain cavity.

6. The gas curtain protection device for the laser scattering detection of particles as claimed in claim 1, wherein said two kinds of rotating gas curtains include a clean gas curtain moving toward said protection lens and a separation gas curtain moving toward said gas chamber.

7. The air curtain protection device for detecting the particulate matters through laser scattering according to claim 1, further comprising an air pump, which is arranged at the sample gas outlet and is used for forming a negative pressure in the air chamber to facilitate the discharge of the sample gas.

8. The gas curtain protection device for detecting the particles through laser scattering of claim 1, further comprising an optical trap, wherein the optical trap is arranged opposite to the gas chamber relative to the laser, and the optical trap is positioned above the receiver.

9. The air curtain protection device for detecting particles through laser scattering according to claim 1, wherein the light emitting direction of the laser is at an angle a with the light sensing direction of the receiver, wherein the angle a is in a range of 10 ° < a <20 °.

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