CN112098281A - Laser dust sensor - Google Patents
Laser dust sensor Download PDFInfo
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- CN112098281A CN112098281A CN202010830246.7A CN202010830246A CN112098281A CN 112098281 A CN112098281 A CN 112098281A CN 202010830246 A CN202010830246 A CN 202010830246A CN 112098281 A CN112098281 A CN 112098281A
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- 239000000428 dust Substances 0.000 title claims abstract description 75
- 238000001514 detection method Methods 0.000 claims abstract description 64
- 230000000149 penetrating effect Effects 0.000 claims abstract description 3
- 238000005192 partition Methods 0.000 claims description 100
- 238000009423 ventilation Methods 0.000 claims description 8
- 206010010904 Convulsion Diseases 0.000 claims description 2
- 230000036461 convulsion Effects 0.000 claims description 2
- 230000002035 prolonged effect Effects 0.000 abstract description 3
- 238000004062 sedimentation Methods 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 238000004026 adhesive bonding Methods 0.000 description 2
- 238000001746 injection moulding Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 239000002386 air freshener Substances 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012986 modification Methods 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
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
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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
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/24—Suction devices
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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
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
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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
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/47—Scattering, i.e. diffuse reflection
- G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
- G01N21/53—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
- G01N15/075—Investigating concentration of particle suspensions by optical means
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Abstract
The invention relates to a laser dust sensor, which comprises a shielding cover with an air inlet and an air outlet, a middle shell fixed in the shielding cover, a circuit board fixed in the middle shell, an air draft unit, a support fixed on the circuit board, and a laser generation unit fixed on the support, wherein the circuit board is provided with a photoelectric sensor and is electrically connected with the air draft unit and the laser generation unit; the support is provided with a detection cavity, the detection cavity is provided with an air inlet and an air outlet, and the side wall close to the circuit board is provided with a through hole penetrating through the thickness of the circuit board so as to expose the photoelectric sensor; the shielding cover, the circuit board and the middle shell form an air inlet duct communicated with the air inlet and the air inlet, and a lifting structure is arranged in the air inlet duct and used for lifting the air flow entering the air inlet towards the direction away from the through hole in the axis direction parallel to the through hole, so that dust in the air flow is reduced to be accumulated on the photoelectric sensor due to natural sedimentation, the detection precision and reliability of the laser dust sensor are improved, and the service life is prolonged.
Description
Technical Field
The invention relates to the technical field of dust detection, in particular to a laser dust sensor.
Background
In recent years, with the gradual improvement of quality of life, people have higher and higher attention to air quality, and a laser dust sensor detects the concentration condition of dust in air by adopting an optical scattering principle, can quickly detect the air quality, is widely applied to equipment such as air fresheners, air purifiers, environment monitoring equipment, air conditioners, ventilation equipment, air quality detectors and the like, and is suitable for detecting indoor environments such as factories, offices, rooms and the like.
At present, laser dust sensor mainly includes laser emission device, updraft ventilator and photoelectric detection device, in operation, updraft ventilator drives the air current and gets into the dust detection zone, laser emission device aims at dust detection zone transmission laser pulse, laser can produce the scattered light when meetting the dust, partial scattered light returns photoelectric detection device, photoelectric detection device turns into the light signal who obtains and the concentration condition of dust in the signal of telecommunication and the analysis air, but dust in the air current piles up in photoelectric detection device department easily among the current laser dust sensor, it is not high to lead to laser dust sensor detection precision, the output result is inconsistent, and along with the increase sensor precision reduction of live time, and then reduce laser dust sensor's life.
Disclosure of Invention
In view of this, it is necessary to provide a laser dust sensor that addresses the problems of low detection accuracy and short service life.
The utility model provides a laser dust sensor, is including the shield cover that has air intake and air outlet, be fixed in mesochite in the shield cover, be fixed in respectively the circuit board and the convulsions unit of mesochite are fixed in the support of circuit board and be fixed in the laser generation unit of support, wherein:
the circuit board is provided with a photoelectric sensor and is electrically connected with the air draft unit and the laser generation unit;
the support is provided with a detection cavity, the detection cavity is provided with an air inlet and an air outlet, and the side wall close to the circuit board is provided with a through hole penetrating through the thickness of the circuit board so as to expose the photoelectric sensor;
the shielding cover, the circuit board reaches the mesochite forms the intercommunication the air inlet with the air intake air inlet duct, have the lifting structure in the air inlet duct, be used for entering the air current direction of air inlet is in a parallel with on the axis direction of through-hole to deviating from the through-hole lifting.
In one embodiment, a partition plate assembly is arranged on the middle shell, the partition plate assembly is positioned on the circuit board, at least one partition plate is arranged between the air vent and the air inlet of the circuit board, and a slotted hole is formed in the position, opposite to the air inlet, of the partition plate;
the lifting structure comprises a first inclined plane, wherein the inner wall of the groove hole is close to the through hole in the direction parallel to the axis of the through hole, and the first inclined plane is far away from one end of the air inlet and is lower than the height close to one end of the air inlet in the direction parallel to the axis of the through hole and away from the through hole.
In one embodiment, the number of the partition plates is multiple, the partition plates are arranged at intervals, the partition plate assembly comprises a first partition plate and a second partition plate which are positioned at two sides along the arrangement direction of the air inlets and the air outlets, the first partition plate is adjacent to the air inlets, and in the direction parallel to the axis of the through hole and away from the through hole, the height of one end, close to the air inlets, of the first inclined surface in the first partition plate is larger than the height of one end, close to the air inlets, of the first inclined surface in the second partition plate.
In one embodiment, in a direction parallel to the axis of the through hole and away from the through hole, the height of the first inclined surface of the partition plate close to the air inlet at one end close to the air inlet is greater than the height of the first inclined surface of the partition plate far away from the air inlet at one end close to the air inlet.
In one embodiment, in a direction parallel to the axis of the through hole and away from the through hole, the height of the first inclined surface of the partition plate close to the air inlet, at the end far away from the air inlet, is greater than or equal to the height of the first inclined surface of the partition plate far away from the air inlet, at the end near the air inlet.
In one embodiment, the lifting structure further includes a second inclined surface on a portion of the circuit board between the partition board assembly and the ventilation opening of the circuit board, in a direction parallel to the axis of the through hole and away from the through hole, a height of an end of the second inclined surface, which is far away from the air inlet, is smaller than a height of the second inclined surface, which is close to the air inlet, at an end of the second inclined surface, which is close to the air inlet, and is smaller than or equal to a height of the first inclined surface, which is far away from the air inlet, in the partition board adjacent to the second inclined surface at an end of the second inclined.
In one embodiment, the first inclined surface forms an angle of 4.5-9 ° with a plane perpendicular to the axis of the through hole.
In one embodiment, the lifting structure comprises a third inclined surface on the area between the ventilation opening of the circuit board and the air inlet, and the height of one end, away from the air inlet, of the third inclined surface is smaller than the height of one end, close to the air inlet, of the third inclined surface in the direction parallel to the axis of the through hole and away from the through hole.
In one embodiment, the angle between the third inclined surface and the plane perpendicular to the axis of the through hole is 4.5-9 degrees.
In one embodiment, the laser generating unit is arranged coaxially with the support, and the axial direction of the laser generating unit is located right above the through hole.
In the laser dust sensor, the circuit board controls the air draft unit and the laser generating unit to work to drive airflow to enter the air inlet duct through the air inlet, the laser generating unit emits laser pulses to the detection cavity after the airflow enters the detection cavity, laser generates scattered light when encountering dust in the airflow, part of the scattered light returns to the photoelectric sensor, the photoelectric sensor converts an obtained optical signal into an electric signal and analyzes the concentration condition of the dust in the air through the circuit board, and air quality detection is realized; and because the air inlet duct is internally provided with the lifting structure, the air flow direction is lifted towards the deviation through hole in the axial direction parallel to the through hole under the action of the lifting structure, so that the air flow direction entering the air inlet has a certain angle relative to the plane perpendicular to the axial direction of the through hole in the detection cavity, and the air flow direction entering the air inlet is inclined towards the direction deviating from the through hole, the position of the photoelectric sensor accumulated by dust in the air flow due to natural sedimentation can be reduced, the detection precision of the laser dust sensor is improved, the reliability of the detection result is higher, and the service life of the laser dust sensor can be prolonged.
Drawings
Fig. 1 is a schematic structural diagram of a laser dust sensor according to an embodiment of the present invention;
FIG. 2 is an exploded view of a laser dust sensor according to an embodiment of the present invention;
FIG. 3 is an exploded view of a module formed by a laser generating unit and a support in a laser dust sensor according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a laser dust sensor provided in an embodiment of the present invention after a shielding case is removed;
FIG. 5 is a schematic structural view of another laser dust sensor according to an embodiment of the present invention after the shielding case is removed;
FIG. 6 is a schematic structural diagram of another laser dust sensor according to an embodiment of the present invention after the shielding case is removed;
FIG. 7 is a schematic structural diagram of another laser dust sensor according to an embodiment of the present invention after removing a shielding case;
fig. 8 is a schematic structural diagram of another laser dust sensor according to an embodiment of the present invention after the shielding cover is removed.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.
As shown in fig. 1, 2, 3 and 4, the present invention provides a laser dust sensor 10 for detecting air quality, the laser dust sensor 10 includes several structures of a shielding case 100, a middle case 200, a circuit board 300, an air draft unit 400, a support 500 and a laser generating unit 600, wherein:
the shielding case 100 has an air inlet 110 and an air outlet 120, the shielding case 100 covers the outside of the middle case 200, and a conductive structure, such as a conductive sheet, is disposed between the circuit board 300 and the shielding case 100, so as to achieve full shielding and interference resistance of multiple surfaces of the laser dust sensor 10, and improve consistency and accuracy of detection results. In a specific arrangement, the shielding case 100 includes two parts, namely an upper shielding case 130 and a lower shielding case 140, and the upper shielding case 130 and the lower shielding case 140 may be made of a metal material, which not only ensures that the shielding case 100 has a light weight, but also increases the capability of resisting electromagnetic interference, and preferably, the shielding case 100 may be made of a stainless steel plate, and the thickness of the stainless steel plate is preferably 0.3mm or more.
The middle shell 200 may be fixed inside the shield case 100 by a mechanical connection manner such as a screw connection, a snap connection, a concave-convex fit, and the middle shell 200 may also be fixed inside the shield case 100 by a physical connection manner such as an adhesive connection. In specific setting, the middle shell 200 may be formed by injection molding using a plastic material to meet the requirement of structural accuracy, and of course, the material and the manufacturing process of the middle shell 200 are not limited thereto, and may be in other forms that can meet the requirement; the middle shell 200 is provided with an installation position of the exhaust unit 400 so as to facilitate the installation of the exhaust unit 400.
The circuit board 300 may be fixed inside the middle case 200 by a mechanical connection manner such as a screw connection, a snap connection, a concave-convex fit, and the like, and the circuit board 300 may also be fixed inside the middle case 200 by a physical connection manner such as an adhesive connection. The circuit board 300 includes a photoelectric sensor 310 and a processing unit 320, the photoelectric sensor 310 is electrically connected to the processing unit 320, the photoelectric sensor 310 is configured to receive an optical signal and convert the optical signal into an electrical signal, and the processing unit 320 receives the electrical signal to analyze the concentration of dust in air.
The exhaust unit 400 can be fixed on the exhaust unit 400 mounting position of the middle shell 200 through mechanical connection modes such as buckle connection and concave-convex matching, and the exhaust unit 400 can also be fixed on the exhaust unit 400 mounting position through physical connection modes such as gluing. The air draft unit 400 is electrically connected with the circuit board 300, and the air draft unit 400 is controlled by the circuit board 300 to draft air. When specifically setting up, the exhaust unit 400 can be the fan, and the exhaust unit 400 still can be other structural style that can satisfy the requirement.
The support 500 may be fixed inside the middle case 200 through mechanical connection methods such as a screw connection, a snap connection, a concave-convex fit, and the support 500 may also be fixed inside the middle case 200 through physical connection methods such as a glue connection. The support 500 is provided with a detection cavity 510, the detection cavity 510 is provided with an air inlet 511 and an air outlet 512, the side wall of the detection cavity 510 close to the circuit board 300 is provided with a through hole 513, the through hole 513 penetrates through the thickness of the side wall of the detection cavity 510 close to the circuit board 300, the through hole 513 is opposite to the photoelectric sensor 310 so as to expose the photoelectric sensor 310, the photoelectric sensor 310 receives light, when the detection cavity is specifically arranged, the support 500 can be made of plastic materials and formed through an injection molding process so as to meet the requirement of structural accuracy, and of course, the material and the preparation process of the support 500 are not limited to the above, and the support can also be in.
The laser generating unit 600 can be fixed inside the support 500 through mechanical connection modes such as snap connection and concave-convex fit, and the laser generating unit 600 can also be fixed inside the support 500 through physical connection modes such as gluing. The laser generating unit 600 is electrically connected to the circuit board 300, and the circuit board 300 controls the laser generating unit 600 to generate laser pulses. In a specific arrangement, the laser generating unit 600 may be a laser, and the laser generating unit 600 may also be in other structural forms capable of meeting the requirements.
The shielding case 100, the circuit board 300 and the middle case 200 form an air inlet duct 700, the air inlet duct 700 is communicated with the air inlet 511 and the air inlet 110, the shielding case 100 and the middle case 200 form an air outlet duct, the air outlet duct is communicated with the air outlet 512 and the air outlet 120, when the exhaust unit 400 operates, external air flow enters the air inlet duct 700 through the air inlet 511, is transmitted to the air inlet 511 through the air inlet duct 700, enters the air outlet duct from the air outlet 512 after being detected in the detection cavity 510, and is discharged from the air outlet 120 through a fan. The air inlet duct 700 has a lifting structure 800 therein, and the lifting structure 800 is used for lifting the direction of the air flow entering the air inlet 511 in the direction parallel to the axis of the through hole 513 and away from the through hole 513, so as to increase the falling time of the dust in the air flow entering the air inlet 511, and thus to discharge more dust from the air outlet 512.
In the laser dust sensor 10, the circuit board 300 controls the air draft unit 400 and the laser generating unit 600 to work, so as to drive the air flow to enter the air inlet duct 700 through the air inlet 110, after the air flow enters the detection cavity 510, the laser generating unit 600 emits laser pulses to the detection cavity 510, laser generates scattered light when encountering dust in the air flow, part of the scattered light returns to the photoelectric sensor 310, the photoelectric sensor 310 converts the obtained optical signal into an electrical signal, and the concentration condition of the dust in the air is analyzed through the processing unit 320, so that the detection of the air quality is realized; and since the air inlet duct 700 has the lifting structure 800 therein, the direction of the air flow is lifted away from the through hole 513 in the direction parallel to the axis of the through hole 513 by the lifting structure 800, the direction of the air flow entering the air inlet 511 is made to have an angle with respect to a plane perpendicular to the axial direction of the through hole 513 in the detection chamber 510, and the direction of the airflow entering the air inlet 511 inclines towards the direction deviating from the through hole 513, so that the dust in the airflow can be reduced from being accumulated at the position of the photoelectric sensor 310 due to natural sedimentation, the detection precision of the laser dust sensor 10 is improved, the reliability of the detection result is higher, moreover, the problem that the detection precision of the laser dust sensor 10 is not high due to the accumulation of dust at the position of the photoelectric sensor 310 can be alleviated, the service life of the laser dust sensor 10 is prolonged, and the long-term stability of the test precision is ensured.
The lifting structure 800 has various forms, as shown in fig. 5, 6 and 7, in a preferred embodiment, the middle shell 200 is provided with a partition assembly 210, the partition assembly 210 is integrally formed with the middle shell 200, or the partition assembly 210 is fixed on the middle shell 200 by means of a snap connection, a male-female fit, an adhesive connection, or the like. The partition plate assembly 210 is positioned above the circuit board 300, and the partition plate assembly 210 is positioned between the air vent 330 and the air inlet 511 of the circuit board 300, and the partition plate assembly 210 divides the middle case 200 into two parts along the arrangement direction of the air inlet 511 and the air outlet 512. The partition plate assembly 210 comprises at least one partition plate 211, slot holes 220 are formed in the positions, facing the air inlets 511, of the partition plates 211, and are used for air flow to pass through.
The lifting structure 800 comprises a first inclined surface 221 of the inner wall of the slot 220 close to the through hole 513 in the direction parallel to the axis of the through hole 513, when the number of the partition boards 211 is one, the lifting structure 800 is the first inclined surface 221 on the partition board 211, and when the number of the partition boards 211 is multiple, the lifting structure 800 is a structure formed by combining the first inclined surfaces 221 of the partition boards 211. In a direction parallel to the axis of the through hole 513 and away from the through hole 513, the height of the first inclined surface 221 at the end away from the air inlet 511 is smaller than the height at the end close to the air inlet 511, so that the first inclined surface 221 has an angle with a plane perpendicular to the axis of the through hole 513, and the first inclined surface 221 is inclined in a direction away from the through hole 513.
In the above laser dust sensor 10, by defining the lifting structure 800 including the first inclined surface 221 of the inner wall of the slot 220 near the through hole 513 in the direction parallel to the axis of the through hole 513, and in the direction parallel to the axis of the through hole 513 and away from the through hole 513, the height of the first inclined surface 221 at the end away from the air inlet 511 is smaller than the height at the end near the air inlet 511, so that the direction of the airflow is parallel to the first inclined surface 221 when the airflow is transmitted along the first inclined surface 221, and is lifted relative to the end away from the air inlet 511 when entering the first inclined surface 221, so that the direction of the airflow entering the air inlet 511 has an angle relative to a plane perpendicular to the axis direction of the through hole 513 in the detection chamber 510, and the direction of the airflow entering the air inlet 511 is inclined toward the direction away from the. In a specific arrangement, the slot hole 220 may be a square hole or a square groove, the first inclined surface 221 is a plane, and the height of the first inclined surface 221 in a direction close to the air inlet 511, in a direction parallel to the axis of the through hole 513 and away from the through hole 513, is gradually increased, the slot hole 220 may also be a cylindrical hole or a cylindrical groove, the first inclined surface 221 is an arc-shaped surface, and the height of the first inclined surface 221 in a direction close to the air inlet 511, in a direction parallel to the axis of the through hole 513 and away from the through hole 513, is gradually increased, of course, the structural form of the first inclined surface 221 is not limited thereto, and may also be other forms capable of meeting the requirements. When the number of the partition plates 211 is one, the partition plates 211 are disposed near the air inlet 511 to prevent the air flow from falling back.
In order to ensure the detection accuracy and the detection reliability, specifically, the angle between the first inclined surface 221 and the plane perpendicular to the axis of the through hole 513 may be 4.5 ° to 9 °. Of course, the angle between the first inclined surface 221 and the plane perpendicular to the axis of the through hole 513 is not limited to the above range, and may be other values as required.
In the laser dust sensor 10, the included angle between the first inclined plane 221 and the plane perpendicular to the axis of the through hole 513 is limited to be 4.5-9 degrees, so that the included angle between the first inclined plane 221 and the plane perpendicular to the axis of the through hole 513 is smaller, more dust is prevented from directly staying on the side wall opposite to the detection chamber 510 and the through hole 513, more dust in the airflow meets with the laser and generates scattered light, the detection accuracy is ensured, the dust staying on the side wall opposite to the detection chamber 510 and the through hole 513 can be prevented from influencing the next detection process, and the detection result is more reliable. In a specific arrangement, the angle between the first inclined surface 221 and the plane perpendicular to the axis of the through hole 513 may be 4.5 ° to 9 °, and preferably, the angle between the first inclined surface 221 and the plane perpendicular to the axis of the through hole 513 is 4.5 °, 5 °, 5.5 °, 6 °, 6.5 °, 7 °, 7.5 °, 8 °, 8.5 °, 9 °, although the angle between the first inclined surface 221 and the plane perpendicular to the axis of the through hole 513 is not limited to the above value, and may be other values within the interval of 4.5 ° to 9 °. It is noted that, when the number of the partition 211 is one, the angle between the first inclined surface 221 in the partition 211 and a plane perpendicular to the axis of the through hole 513 may be 4.5 ° to 9 °; when the number of the partitions 211 is plural, the angle between the first inclined surface 221 of each partition 211 and a plane perpendicular to the axis of the through-hole 513 may be 4.5 to 9 °, or the angle between the first inclined surface 221 of the partition 211 adjacent to the air inlet 511 and a plane perpendicular to the axis of the through-hole 513 may be 4.5 to 9 °.
The partition plate assembly 210 has a plurality of structural forms, and in a preferred embodiment, as shown in fig. 5 and 7, the number of the partition plates 211 is multiple, the partition plates 211 are arranged at intervals, and the partition plate assembly 210 includes a first partition plate 212 and a second partition plate 213 which are located at two sides along the arrangement direction of the air inlet 511 and the air outlet 512, the first partition plate 212 is adjacent to the air inlet 511, and in the direction parallel to the axis of the through hole 513 and away from the through hole 513, the height of the first inclined surface 221 of the first partition plate 212 at the end close to the air inlet 511 is greater than the height of the first inclined surface 221 of the second partition plate 213 at the end close to the air inlet 511.
In the above laser dust sensor 10, by defining the first partition 212 adjacent to the air inlet 511 and in a direction parallel to the axis of the through-hole 513 and away from the through-hole 513, the height of the first inclined surface 221 of the first partition 212 at the end close to the air inlet 511 is greater than the height of the first inclined surface 221 of the second partition 213 at the end close to the air inlet 511, so that the air flow transmitted from the second partition 213 to the first partition 212 is lifted, so that the direction of the air flow transmitted from the first inclined surface 221 of the first partition 212 at the end close to the air inlet 511 into the air inlet 511 is lifted relative to the second partition 213, so that the direction of the air flow entering the air inlet 511 has an angle relative to a plane perpendicular to the axial direction of the through-hole 513 in the detection chamber 510, and the direction of the air flow entering the air inlet 511 is inclined toward the direction away from the through-hole 513. When specifically setting up, a plurality of baffles 211 are arranged at a certain distance apart to avoid first inclined plane 221 longer, lead to the dust in the air current directly to stop on first inclined plane 221, thereby improve the precision of detection and the reliability of testing result. And at this time, the angle between the first inclined surface 221 in the first barrier 212 and a plane perpendicular to the axis of the through hole 513 may be 4.5 ° to 9 °.
In order to further improve the detection accuracy and the reliability of the detection result, in particular, in the two adjacent partition boards 211, in the direction parallel to the axis of the through hole 513 and away from the through hole 513, the height of the first inclined surface 221 of the partition board 211 close to the air inlet 511 at the end close to the air inlet 511 is greater than the height of the first inclined surface 221 of the partition board 211 far away from the air inlet 511 at the end close to the air inlet 511.
In the laser dust sensor 10, the height of the first inclined surface 221 close to the air inlet 511 in the partition 211 close to the air inlet 511 is larger than the height of the first inclined surface 221 close to the air inlet 511 in the partition 211 far away from the air inlet 511, so that the airflow direction is lifted when the airflow passes through any one of the first inclined surfaces 221, the airflow direction entering the air inlet 511 is enabled to have a certain angle relative to a plane perpendicular to the axial direction of the through hole 513 in the detection chamber 510, and the airflow direction entering the air inlet 511 is inclined towards a direction away from the through hole 513. In a specific arrangement, the angle between the first inclined surface 221 of each partition 211 and a plane perpendicular to the axis of the through hole 513 may be 4.5 ° to 9 °, or the angle between the first inclined surface 221 of the first partition 212 and a plane perpendicular to the axis of the through hole 513 may be 4.5 ° to 9 °.
In order to avoid the first inclined surface 221 from having a great influence on the flow velocity of the air flow, in two adjacent partition plates 211, in a direction parallel to the axis of the through hole 513 and away from the through hole 513, the height of the first inclined surface 221 away from the air inlet 511 in the partition plate 211 close to the air inlet 511 is greater than or equal to the height of the first inclined surface 221 close to the air inlet 511 in the partition plate 211 away from the air inlet 511.
In the laser dust sensor 10, the height of the first inclined surface 221 far away from the air inlet 511 in the partition 211 close to the air inlet 511 is greater than or equal to the height of the first inclined surface 221 near the air inlet 511 in the partition 211 far away from the air inlet 511, so that the plurality of first inclined surfaces 221 gradually lift the air flow, and the air flow is ensured to be transmitted smoothly. In a specific arrangement, in a direction parallel to the axis of the through hole 513 and away from the through hole 513, in two adjacent partition plates 211, the height of the first inclined surface 221 of the partition plate 211 close to the air inlet 511, which is away from the air inlet 511, from the end of the air inlet 511 may be greater than the height of the first inclined surface 221 of the partition plate 211 away from the air inlet 511, which is away from the air inlet 511, from the end of the air inlet 511, and the height of the first inclined surface 221 of the partition plate 211 close to the air inlet 511, which is away from the air inlet 511, from the end of the air inlet 511 may also be equal to; for example, the height of the first inclined plane 221 away from the air inlet 511 in the partition 211 close to the air inlet 511 is equal to the height of the first inclined plane 221 away from the air inlet 511 in the partition 211 close to the air inlet 511, and the included angle between the plurality of first inclined planes 221 and a plane perpendicular to the axial direction of the through hole 513 gradually increases along the direction close to the air inlet 511, so that the included angle between the first inclined plane 221 close to the air inlet 511 and the plane perpendicular to the axial direction of the through hole 513 may be 4.5-9 °, and the included angle between the first inclined plane 221 away from the air inlet 511 and the plane perpendicular to the axial direction of the through hole 513 is less than 4.5 °; for another example, the height of the first inclined surface 221 of the partition 211 close to the air inlet 511 from the end of the air inlet 511 is equal to the height of the first inclined surface 221 of the partition 211 far from the air inlet 511 from the end of the air inlet 511, and the included angles between the plurality of first inclined surfaces 221 and the plane perpendicular to the axial direction of the through hole 513 are the same and are all within the interval of 4.5-9 °.
The form of the lifting structure 800 has various forms, and in a preferred embodiment, as shown in fig. 5, the lifting structure 800 further includes a second inclined surface 340 on a portion of the circuit board 300 between the partition plate assembly 210 and the ventilation opening 330 of the circuit board 300, in a direction parallel to the axis of the through hole 513 and away from the through hole 513, a height of an end of the second inclined surface 340 away from the air inlet 511 is smaller than a height of an end of the second inclined surface 340 close to the air inlet 511, and a height of an end of the second inclined surface 340 close to the air inlet 511 is smaller than or equal to a height of an end of the first inclined surface 221 away from the air inlet 511 in the partition plate 211 adjacent thereto.
In the laser dust sensor 10, the second inclined surface 340 is arranged, and the height of the end, far away from the air inlet 511, of the second inclined surface 340 is smaller than the height of the end, near the air inlet 511, of the second inclined surface 340, and the height of the end, near the air inlet 511, of the second inclined surface 340 is smaller than or equal to the height of the end, far away from the air inlet 511, of the first inclined surface 221 of the adjacent partition 211, so that the airflow direction can be lifted under the action of the second inclined surface 340 after passing through the ventilation opening 330, and then further lifted under the action of the first inclined surface 221 of the partition assembly 210. In a specific arrangement, in a direction parallel to the axis of the through hole 513 and away from the through hole 513, the height of the end, close to the air inlet 511, of the second inclined surface 340 may be equal to the height, away from the air inlet 511, of the first inclined surface 221 in the partition 211 adjacent to the second inclined surface 511, and in a direction parallel to the axis of the through hole 513 and away from the through hole 513, the height, close to the air inlet 511, of the second inclined surface 340 may be smaller than the height, away from the air inlet 511, of the first inclined surface 221 in the partition 211 adjacent to the second inclined surface 340; for example, the height of the second inclined surface 340 near the end of the air inlet 511 may be equal to the height of the first inclined surface 221 far from the end of the air inlet 511 in the adjacent partition 211, and the included angle between the second inclined surface 340 and the plurality of first inclined surfaces 221 and the plane perpendicular to the axial direction of the through hole 513 gradually increases along the direction near the air inlet 511, so that the included angle between the first inclined surface 221 near the air inlet 511 and the plane perpendicular to the axial direction of the through hole 513 may be 4.5 ° to 9 °, and the included angle between the second inclined surface 340 and the plane perpendicular to the axial direction of the through hole 513 is less than 4.5 °; for another example, the height of the second inclined surface 340 near the end of the air inlet 511 may be equal to the height of the first inclined surface 221 of the adjacent partition 211 far from the end of the air inlet 511, and the included angles between the second inclined surface 340 and the plurality of first inclined surfaces 221 and the plane perpendicular to the axial direction of the through hole 513 along the direction near the air inlet 511 are all within the interval of 4.5 ° to 9 °.
The form of the lifting structure 800 has various forms, and in a preferred embodiment, as shown in fig. 8, the lifting structure 800 includes a third inclined surface 350 on an area between the ventilation opening 330 and the air inlet opening 511 of the circuit board 300, and in a direction parallel to an axis of the through-hole 513 and away from the through-hole 513, a height of an end of the third inclined surface 350 away from the air inlet opening 511 is smaller than a height of an end of the third inclined surface 350 close to the air inlet opening 511, so that the third inclined surface 350 forms an angle with a plane perpendicular to the axis of the through-hole 513, and the third inclined surface 350 is inclined in a direction away from the through-hole 513.
In the laser dust sensor 10, the third inclined surface 350 of the lifting structure 800 is defined, and the height of the end, away from the air inlet 511, of the third inclined surface 350 in the direction parallel to the axis of the through hole 513 and away from the through hole 513 is smaller than the height of the end, close to the air inlet 511, of the third inclined surface 350, so that the airflow direction is parallel to the third inclined surface 350 when the airflow is transmitted along the third inclined surface 350, and is lifted relative to the end, away from the air inlet 511, of the third inclined surface 350, so that the airflow direction entering the air inlet 511 is at a certain angle relative to the plane perpendicular to the axis direction of the through hole 513 in the detection chamber 510, and the airflow direction entering the air inlet 511 is inclined towards the direction away from the through hole 513. In a specific arrangement, the third inclined plane 350 may be disposed in the entire area between the air permeation opening 330 and the air intake opening 511 of the circuit board 300, and the third inclined plane 350 may be disposed in the area of the circuit board 300 between the air permeation opening 330 and the air intake opening 511, which is opposite to the air intake opening 511; the third inclined surface 350 may be a continuous surface, and the third inclined surface 350 may also include a plurality of sub-surfaces, and in a direction parallel to the axis of the through hole 513 and away from the through hole 513, a height of the sub-surface close to the end of the air inlet 511 close to the air inlet 511 is greater than a height of the sub-surface far from the end of the air inlet 511 close to the air inlet 511, or a height of the sub-surface close to the end of the air inlet 511 far from the air inlet 511 is greater than or equal to a height of the sub-surface far from the end of the air inlet 511.
In order to ensure the detection accuracy and the detection reliability, the angle between the third inclined surface 350 and the plane perpendicular to the axis of the through hole 513 is 4.5-9 degrees. Of course, the angle between the third inclined surface 350 and the plane perpendicular to the axis of the through hole 513 is not limited to the above range, and may be other values as required.
In the laser dust sensor 10, the included angle between the third inclined surface 350 and the plane perpendicular to the axis of the through hole 513 is limited to be 4.5-9 degrees, so that the included angle between the third inclined surface 350 and the plane perpendicular to the axis of the through hole 513 is smaller, more dust is prevented from directly staying on the side wall opposite to the detection chamber 510 and the through hole 513, more dust in the airflow is ensured to meet with the laser and generate scattered light, the detection accuracy is ensured, the dust staying on the side wall opposite to the detection chamber 510 and the through hole 513 can be prevented from influencing the next detection process, and the detection result is more reliable. In a specific arrangement, the angle between the third inclined surface 350 and the plane perpendicular to the axis of the through hole 513 may be 4.5 ° to 9 °, and preferably, the angle between the third inclined surface 350 and the plane perpendicular to the axis of the through hole 513 is 4.5 °, 5 °, 5.5 °, 6 °, 6.5 °, 7 °, 7.5 °, 8 °, 8.5 °, 9 °, although the angle between the third inclined surface 350 and the plane perpendicular to the axis of the through hole 513 is not limited to the above value, and may be other values within the interval of 4.5 ° to 9 °. It is noted that, when the number of the third inclined surfaces 350 is one, the angle between the third inclined surface 350 and a plane perpendicular to the axis of the through hole 513 may be 4.5 ° to 9 °; where the third inclined surface 350 comprises a plurality of sub-surfaces, each sub-surface may be at an angle of 4.5 ° -9 ° to a plane perpendicular to the axis of the through-hole 513, or the sub-surface adjacent the air inlet 511 may be at an angle of 4.5 ° -9 ° to a plane perpendicular to the axis of the through-hole 513.
In order to ensure the accuracy of laser detection, as shown in fig. 3, in a preferred embodiment, the laser generating unit 600 is disposed coaxially with the support 500, and the axial direction of the laser generating unit 600 is located directly above the through hole 513.
In the laser dust sensor 10, the laser generating unit 600 and the support 500 are coaxially arranged, and the axis direction of the laser generating unit 600 is limited to be located right above the through hole 513, so that the mounting position precision of the laser generating unit 600 is ensured, and meanwhile, the laser detection position precision can be ensured, so that the laser detection precision is higher, the detection precision is higher, and the detection result is more reliable. When the air draft unit 400 generates air flow of 0.028m/min-0.031m/min during specific setting, the cross-sectional area of the detection cavity 510 along the direction parallel to the axis of the through hole 513 is 3.9mm x 6mm, and the distance from the center of the through hole 513 to one end, close to the air inlet 511, of the lifting structure 800 is 4mm-6mm, large ion (PM5-PM10) particles in the air flow are distributed uniformly in the middle of the channel, and the detection precision is high. Preferably, the airflow generated by the ventilation unit 400 may be 0.028m/min, 0.029m/min, 0.030m/min and 0.031m/min, the distance from the center of the through hole 513 to the end of the lifting structure 800 close to the air inlet 511 may be 4mm, 4.5mm, 5mm, 5.5mm, 5.8mm and 6mm, and the specific implementation manner of the laser dust sensor 10 may be to select the above combination values.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. The utility model provides a laser dust sensor, its characterized in that, including the shield cover that has air intake and air outlet, be fixed in mesochite in the shield cover, be fixed in respectively the circuit board and the convulsions unit of mesochite are fixed in the support of circuit board and be fixed in the laser generation unit of support, wherein:
the circuit board is provided with a photoelectric sensor and is electrically connected with the air draft unit and the laser generation unit;
the support is provided with a detection cavity, the detection cavity is provided with an air inlet and an air outlet, and the side wall close to the circuit board is provided with a through hole penetrating through the thickness of the circuit board so as to expose the photoelectric sensor;
the shielding cover, the circuit board reaches the mesochite forms the intercommunication the air inlet with the air intake air inlet duct, have the lifting structure in the air inlet duct, be used for entering the air current direction of air inlet is in a parallel with on the axis direction of through-hole to deviating from the through-hole lifting.
2. The laser dust sensor according to claim 1, wherein a partition plate assembly is arranged on the middle shell, the partition plate assembly is positioned on the circuit board, at least one partition plate is arranged between the air vent and the air inlet of the circuit board, and a slot hole is formed in a position, opposite to the air inlet, of the partition plate;
the lifting structure comprises a first inclined plane, wherein the inner wall of the groove hole is close to the through hole in the direction parallel to the axis of the through hole, and the first inclined plane is far away from one end of the air inlet and is lower than the height close to one end of the air inlet in the direction parallel to the axis of the through hole and away from the through hole.
3. The laser dust sensor as claimed in claim 2, wherein the number of the partition plates is plural, the plural partition plates are arranged at intervals, the partition plate assembly includes a first partition plate and a second partition plate which are located at both sides along the arrangement direction of the gas inlet and the gas outlet, the first partition plate is adjacent to the gas inlet, and the height of the first inclined surface at one end of the first partition plate close to the gas inlet is larger than the height of the first inclined surface at one end of the second partition plate close to the gas inlet in a direction parallel to the axis of the through hole and away from the through hole.
4. The laser dust sensor as claimed in claim 3, wherein in two adjacent partitions, in a direction parallel to the axis of the through hole and away from the through hole, the height of the first inclined surface of the partition near the air inlet is greater at an end near the air inlet than at an end far from the air inlet.
5. The laser dust sensor as claimed in claim 3, wherein in a direction parallel to the axis of the through hole and away from the through hole, a height of the first inclined surface of the partition plate close to the air inlet at an end away from the air inlet is greater than or equal to a height of the first inclined surface of the partition plate away from the air inlet at an end close to the air inlet.
6. The laser dust sensor as claimed in claim 2, wherein the lifting structure further includes a second inclined surface on a portion of the circuit board between the partition plate assembly and the ventilation opening of the circuit board, in a direction parallel to the axis of the through hole and away from the through hole, a height of an end of the second inclined surface away from the air inlet is smaller than a height of an end of the second inclined surface close to the air inlet, and a height of an end of the second inclined surface close to the air inlet is smaller than or equal to a height of an end of the first inclined surface away from the air inlet in the partition plate adjacent to the second inclined surface.
7. The laser dust sensor of claim 2 wherein the first slope is at an angle of 4.5 ° -9 ° to a plane perpendicular to the axis of the through hole.
8. The laser dust sensor of claim 1, wherein the lifting structure comprises a third inclined surface on a region between the gas-permeable port of the circuit board and the gas inlet, and a height of an end of the third inclined surface away from the gas inlet is smaller than a height of an end of the third inclined surface close to the gas inlet in a direction parallel to an axis of the through hole and away from the through hole.
9. The laser dust sensor of claim 8 wherein the third slope is at an angle of 4.5 ° -9 ° to a plane perpendicular to the axis of the through hole.
10. The laser dust sensor according to claim 1, wherein the laser generating unit is disposed coaxially with the mount, and an axial direction of the laser generating unit is located directly above the through hole.
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| CN2020108062162 | 2020-08-12 | ||
| CN202010806216 | 2020-08-12 |
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