KR20220036739A - Dust sensor - Google Patents

Abstract

Provided is a dust sensor. The dust sensor according to one aspect of the present invention is the dust sensor measuring dust concentration in air and comprises: a first passage formed inside the dust sensor; a second passage formed inside the dust sensor and connected with the first passage; a detection unit disposed on the second passage; and a moisture removal unit which is disposed on the second passage and is disposed between the detection unit and the first passage. The dust sensor reduces measurement error of the dust concentration due to moisture.

Description

Dust Sensor {DUST SENSOR}

The present invention relates to a dust sensor. More particularly, it relates to a dust sensor in which a moisture removal unit is mounted in an air passage inside the dust sensor.

As the population is dense and the number of vehicles increases, air pollution becomes more severe, and interest in dust is growing, and the demand for air purifiers is also increasing. For active air cleaning, the air purifier requires a dust sensor for measuring the degree of air pollution, that is, the concentration of dust in the air.

As the dust sensor, a photoelectric dust sensor is mainly used. The photoelectric dust sensor forms an air inlet and an outlet in the housing, passes air flowing in from the inlet through the air passage path and discharges it through the outlet, and a light emitting unit disposed in the air passage allows light to enter the detection space. The light emitting unit emits light and the light receiving unit disposed in the air passage condenses the scattered light scattered by the dust, and the concentration of dust contained in the air is measured using the electric signal of the light receiving unit.

The detection unit for detecting the concentration of dust contained in the air is a space in which the light emitting unit and the light receiving unit are disposed in the air passage path between the outlet of the inlet through which air is introduced and the inlet of the outlet through which the air flows. It is a scattering space.

If there is no dust or smoke in the air passing through the air passage, almost all of the light emitted from the light emitting unit passes through the detection space to reach the light-shielding area where the light receiving unit is not disposed, so that the light receiving amount of the light receiving unit becomes very small. On the other hand, if there is dust or smoke in the air passing through the air passage, part of the light emitted from the light emitting unit is scattered by the dust or smoke in the detection space and is incident on the light receiving unit, and the amount of light received by the light receiving unit increases.

Accordingly, it is possible to detect the presence/absence of dust or smoke passing through the air passage path based on output fluctuations of the light receiving element (or photo detector) included in the light receiving unit, and also based on the output level of the photo detector It is possible to detect the concentration of dust or smoke passing through the air passage.

Dust concentration is defined as the total weight of dust particles contained in a unit volume. The scattered light incident on the light receiving unit is proportional to the size or volume of dust particles included in the air passage, and the level of the output signal of the photo detector is also proportional to the volume of the dust particles. Accordingly, the level of the output signal of the photodetector increases when particles of a large volume pass through, and the level of the output signal of the photodetector decreases when particles of a small volume pass through.

Such a dust sensor is disclosed in Korean Patent Application Laid-Open No. 10-2017-017823 A (hereinafter, Prior Art 1).

However, in such a conventional dust sensor, when the humidity in the air is high, moisture may adhere to the dust particles, thereby causing an error in measuring the volume of the dust. 11 is a graph showing the dust concentration according to time measured by the dust sensor according to the prior art. Referring to FIG. 11 , there is a large difference between the dust concentration measured using a standard measuring device and the dust concentration measured using a dust sensor according to the related art in a high humidity time zone. As such, when a large amount of dust including moisture is introduced, there is a problem that the error of the fine dust index (PM2.5, PM10) may increase.

An object of the present specification is to provide a dust sensor capable of reducing a measurement error of a dust concentration due to moisture through a structure capable of removing moisture from dust introduced into the dust sensor.

According to an aspect of the present specification, there is provided a dust sensor for measuring a concentration of dust in air, comprising: a first passage formed inside the dust sensor; a second passage formed inside the dust sensor and communicating with the first passage; a detection unit disposed in the second passage; and a moisture removal unit disposed in the second passage and disposed between the detection unit and the first passage.

In this way, it is possible to reduce the measurement error of the dust concentration due to moisture.

In an embodiment, the moisture removal unit may extend along the second passage, and the moisture removal unit may be disposed on a portion of the flow passage cross-section of the second passage.

In an embodiment, the first passage and the second passage communicate with each other so that the traveling direction changes when the dust enters the second passage from the first passage, and on the passage cross-section of the second passage, the moisture The removal unit may be disposed on a side farther from the first passage.

In an embodiment, the moisture removal unit may include a moisture absorption unit filled with a desiccant therein, an inlet unit disposed at the second passage side, and an outlet unit disposed at the detection unit side.

In an embodiment, the flow path of the inlet part and the outlet part may be formed to be narrower than the flow path of the moisture absorption part.

In one embodiment, on the flow passage cross-section of the second passage, the inlet portion may be disposed to be biased toward the far side from the first passage.

In an embodiment, the moisture removal unit may not overlap the first passage.

A dust sensor according to an aspect of the present specification for achieving the above object is a dust sensor for measuring a concentration of dust in the air, comprising: a housing including an air passage formed in a concave shape on one surface; a cover portion coupled to the outside of the housing and covering the air passage; a detection unit disposed in the air passage; and a moisture removal unit disposed on the air passage.

In an embodiment, the cover part may include an inflow path for communicating the air path with the outside, and the moisture removal unit may be disposed between the detection unit and the inflow path.

In an embodiment, the moisture removal unit may extend along the air passage, and the moisture removal unit may be disposed on a portion of the flow passage cross-section of the air passage.

In an embodiment, the inflow path may be formed through the cover part, and on the flow path cross-section of the air path, the moisture removal part may be disposed on a side farther from the cover part.

Through this specification, it is possible to reduce the measurement error of the dust concentration due to moisture.

1 is a perspective view of a dust sensor according to an embodiment of the present specification viewed from one side.
2 is an exploded perspective view of the dust sensor according to an embodiment of the present specification as viewed from the other side.
3 is a cross-sectional view taken along line X-X' of FIG. 2 of a partial configuration of a dust sensor according to an embodiment of the present specification.
4 schematically shows a detection unit of a dust sensor according to an embodiment of the present specification.
5 schematically shows a partial configuration of a dust sensor according to an embodiment of the present specification.
6 schematically shows a partial configuration of a dust sensor according to another embodiment of the present specification.
7 illustrates a light pulse emitted by a light source of a dust sensor according to an embodiment of the present specification.
8 is a diagram illustrating a signal output by a light receiving unit from a detecting unit of a dust sensor according to an exemplary embodiment of the present specification.
9 is a diagram illustrating a relationship between dust and a signal in the dust sensor according to an embodiment of the present specification.
10 is a graph showing the dust concentration according to time measured by the dust sensor according to an embodiment of the present specification.
11 is a graph showing the dust concentration according to time measured by the dust sensor according to the prior art.

Hereinafter, the embodiments disclosed in the present specification (discloser) will be described in detail with reference to the accompanying drawings, but the same or similar components are assigned the same reference numbers regardless of reference numerals, and redundant description thereof will be omitted.

In the description of the embodiments disclosed in this specification, when a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but It should be understood that other components may exist in between.

In addition, in describing the embodiments disclosed in the present specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical idea disclosed in this specification is not limited by the accompanying drawings, and all changes included in the spirit and scope of the present specification , should be understood to include equivalents or substitutes.

On the other hand, the terms of the specification (discloser) can be replaced with terms such as document, specification, description.

1 is a perspective view of a dust sensor 100 according to an embodiment of the present specification viewed from one side. 2 is an exploded perspective view of the dust sensor 100 according to an embodiment of the present specification as viewed from the other side. 3 is a cross-sectional view taken along line X-X' of FIG. 2 of a partial configuration of the dust sensor 100 according to an embodiment of the present specification. 4 schematically shows the detection unit 150 of the dust sensor 100 according to an embodiment of the present specification.

Hereinafter, the dust sensor 100 according to the present specification will be described with the photoelectric dust sensor 100 measuring the concentration of dust contained in the air introduced into the air passage 140 as an example.

The dust sensor 100 according to an embodiment of the present specification includes a housing 110 , a cover unit 120 , an inflow path 130 , an air path 140 , a detection unit 150 , and a fan unit ( 160) and the moisture removal unit 170 may be included, but may be implemented except for some of these configurations, and additional configurations are not excluded.

The dust sensor 100 may be a photoelectric dust sensor. The photoelectric dust sensor may be a device for measuring the density of dust by a photo detector receiving scattered light scattered by dust contained in air, and outputting it as an electrical signal.

The dust sensor 100 may include a housing 110 . The housing 110 may accommodate internal components such as a detector 150 for detecting a dust concentration, a power supply for supplying power (not shown), and a controller (not shown) for controlling the operation of the dust sensor 100 .

The housing 110 may include a first housing 111 and a second housing 112 . The first housing 111 may mean a housing 110 to which the fan unit 160 is coupled, and the second housing 112 may mean a housing 110 to which the cover unit 120 is coupled.

The first housing 111 and the second housing 112 may be coupled to each other while accommodating the components therein. At this time, the first housing 111 and the second housing 112 may be fitted to each other or may be fastened to each other by the second coupling member 182 . The first housing 111 and the second housing 112 may be formed of various materials such as steel, stainless steel, and plastic.

The dust sensor 100 may include an air passage 140 . The air passage 140 may mean a passage through which the air introduced into the dust sensor 100 may flow. The air passage 140 may be engraved on one surface of the second housing 112 . The cover part 120 may cover one surface of the air passage 140 formed in a concave shape while being coupled to one surface of the second housing 112 . Accordingly, the air passage 140 may be formed in a tunnel shape.

The air passage 140 may further extend to the inside of the housing 110 from the inner end of the portion formed in the concave shape of the second housing 112 . The air passage 140 may extend in various directions and lengths in response to the size of the dust sensor 100 and the arrangement of the fan unit 160 .

Alternatively, the air passage 140 may be manufactured as a separate pipe and coupled to the housing 110 . In this case, the cover part 120 may not be separately coupled to block one surface of the air passage 140 .

The air passage 140 may be formed in various shapes along one surface of the second housing 112 . Referring to FIG. 2 , in order to sufficiently secure a length of a flow path through which air introduced from the outside can pass, the second housing 112 may be formed in a curved shape on one surface. However, the present invention is not limited thereto, and the air passage 140 may extend long in one direction.

The dust sensor 100 may include a cover unit 120 . The cover part 120 may be coupled to the outside of the housing 110 and cover the air passage 140 . Specifically, the cover part 120 may be coupled to one surface of the second housing 112 . In this case, the cover part 120 may cover the air passage 140 formed in the concave shape of the second housing 112 . Accordingly, as described above, the air passage 140 may be formed in a tunnel shape.

The cover part 120 may be coupled to the housing 110 in various ways. For example, it may be coupled to the housing 110 through the second coupling member 182 , may be fitted, or may be coupled using an adhesive.

When the cover part 120 is coupled to the housing 110 by the second coupling member 182 , the second coupling member 182 includes the cover part 120 , the second housing 112 , and the first housing. All of (111) can be penetrated. That is, the first housing 111 , the second housing 112 , and the cover part 120 may be coupled at a time by the second coupling member 182 .

Since the cover part 120 is manufactured and coupled separately from the housing 110 , it may be formed of a material different from that of the housing 110 . For example, the cover part 120 may be formed of a material such as steel, stainless steel, or plastic.

The dust sensor 100 may include an inflow path 130 . The inflow path 130 may be formed through the cover part 120 . The inflow passage 130 may communicate the air passage 140 with the outside.

In order to achieve one object of the present specification, when air is introduced from the inflow passage 130 to the air passage 140 , it may be desirable to change the direction of air flow. In this case, if the length of the inflow path 130 is too short, it may be difficult to effectively change the air flow direction. Accordingly, it may be preferable that the inflow passage 130 has a certain length and communicates with the air passage 140 at the inner end of the inflow passage 130 .

As described above, in order for the inflow path 130 to have a predetermined length, the cover part 120 may be formed to have a predetermined thickness. Since the inflow path 130 is formed through the cover part 120 , if the cover part 120 has a constant thickness, the inflow path 130 may be formed to have a length corresponding to the thickness of the cover part 120 .

In this case, in the second housing 112 , a portion of one surface of the dust sensor 100 may have a step inside, and the cover unit 120 having a certain thickness is provided on a portion of one surface of the dust sensor 100 . can be combined.

The dust sensor 100 may include a detection unit 150 . The detection unit 150 may be disposed in the air passage 140 . Referring to FIG. 2 , the detection unit 150 may be disposed in the air passage 140 . The detection unit 150 includes a light emitting unit 151 emitting light to the air passage 140 inside the dust sensor 100 , and a light receiving unit condensing light scattered by dust contained in the air flowing through the air passage 140 . It may include a 152 and a detection space 153 through which dust passes. The detection unit 150 may measure the concentration of dust passing through the detection space 153 by using the electrical signal of the light receiving unit 152 .

The detection unit 150 may include a detection space 153 . The detection space 153 may be a part of the air passage 140 . That is, air introduced from the outside may pass through the detection space 153 while passing through the air passage 140 .

The detection unit 150 may be disposed in a section extending in a straight line among the air passages 140 . When the air passage 140 is formed in a curved shape, dust may be biased in one direction by centrifugal force in the curved section. When the detection unit 150 is disposed in a curved section of the air passage 140 , the dust is biased toward either side and passes through the detection space 153 of the detection unit 150 , and thus an error may occur in the measurement value. Accordingly, the detection unit 150 may be preferably disposed in a straight section of the air passage 140 .

The detection unit 150 may include a light emitting unit 151 . Assuming that the inner surface of the cover part 120 is the lower surface of the air passage 140 , the light emitting part 151 may be formed on the side surface of the air passage 140 . Light emitted from the light emitting unit 151 may be scattered by dust particles passing through the detection space 153 .

The light emitting unit 151 may include a light source for emitting light of a predetermined band and a light source lens for converting light emitted from the light source into parallel light. The light source may be a laser diode (LD) or an LED. The light source lens may be a collimating lens that converts divergent light into parallel light or a convex lens that converts parallel light into converging light.

The detection unit 150 may include a light receiving unit 152 . The light receiving unit 152 may be a photo detector that generates an electrical signal proportional to the amount of incident light. The light receiving unit 152 may include a light receiving lens for condensing incident light to the photo detector.

The light receiving unit 152 may be disposed at a different angle from the light emitting unit 151 so that the light emitted from the light emitting unit 151 is not directly received by the light receiving unit 152 . Specifically, the light receiving unit 152 includes the cover unit 120 on the inner surface of the air passage 140 so that the direction of the light emitted from the light emitting unit 151 and the direction of the light received from the light receiving unit 152 are perpendicular to each other. They may be disposed at opposite positions. Accordingly, the direction in which the air flowing through the air passage 140 flows, the direction of the light emitted from the light emitting unit 151, and the direction of the light received by the light receiving unit 152 may be perpendicular to each other.

The light emitting unit 151 emits light toward the detection space 153 in a direction perpendicular to the direction in which air flowing through the air passage 140 flows, and the emitted light is contained in the air passing through the detection space 153 . Scattered from the particles, the light receiving unit 152 may measure the intensity of light propagating toward the area occupied by the light receiving unit 152 among the scattered light, and may convert the measured light intensity into an electrical signal. This allows you to measure the concentration of dust in the air.

The detection unit 150 may include a maze unit 154 . The maze part 154 may be disposed to face the light emitting part 151 . Among the light irradiated from the light emitting unit 151 , light that does not collide with dust particles in the detection space 153 may enter the maze unit 154 . At this time, the maze unit 154 may prevent light passing through the detection space 153 from being reflected on the wall constituting the detection space 153 and returning to the light receiving unit 152 or the light emitting unit 151 again. . The maze part 154 may be disposed to face the light emitting part 151 .

The dust sensor 100 may include a fan unit 160 . The fan unit 160 may be coupled to the first housing 111 . The fan unit 160 may be coupled to the first housing 111 through the first coupling member 181 . Alternatively, the fan unit 160 may be coupled to the second housing 112 using an adhesive or the like, or may be coupled to the second housing 112 by being fitted therein.

The fan unit 160 is configured such that air is introduced through the inflow path 130 formed in the cover unit 120 , passes through the air path 140 , and then is discharged to the outside through the fan unit 160 of the first housing 111 . It can generate suction power. The fan unit 160 may include a fan, a motor (not shown) for driving the fan, and a casing (not shown) for accommodating the fan and the motor.

The fan unit 160 may be driven under the control of a controller (not shown). Since the dust sensor 100 according to an embodiment of the present specification measures the dust concentration in the air by measuring the amount of dust included in a constant flow of air, the amount of air passing through the air passage 140 is set at a constant level. It may be desirable to keep Accordingly, the fan unit 160 may generate a suction force so that air flows in the air passage 140 at a constant speed and/or pressure.

For example, when the amount of air passing through the air passage 140 decreases, the control unit transmits a signal to the fan unit 160 , and the fan unit 160 is driven to generate a greater suction force according to the signal. can do. When the amount of air passing through the air passage 140 increases, the controller may transmit a signal to the fan unit 160 and drive the fan unit 160 to generate a smaller suction force according to the signal.

The dust sensor 100 may include a connector (not shown). The connector may connect the control unit for controlling the operation of the dust sensor 100 and the detection unit 150 . The dust sensor 100 may receive a control signal for driving the light emitting unit 151, the light receiving unit 152, and the fan unit 160 from the control unit through the connector, and transmit an output signal of the light receiving unit 152 to the control unit. .

The dust sensor 100 may include a moisture removal unit 170 . The moisture removal unit 170 may be disposed in the air passage 140 . In more detail, the moisture removal unit 170 may be disposed between the detection unit 150 and the inflow path 130 . Dust included in the air introduced from the outside may be introduced into the air passage 140 through the inflow passage 130 , and may be dried while passing through the moisture removal unit 170 before entering the detection unit 150 .

High humidity in the air can cause moisture to stick to dust particles. In this case, the volume of the dust particles may increase. When the volume of the dust particles increases, the light emitted from the light emitting unit 151 may be more scattered by the increased volume of the dust particles. Accordingly, the amount of light received by the light receiving unit 152 increases, so that the dust concentration can be measured to be larger than the actual amount of dust particles.

As such, when a large amount of dust A including moisture is introduced, the fine dust index (PM2.5, PM.10) error may increase. The moisture removal unit 170 dries the dust A including moisture, thereby reducing the measurement error of the dust concentration due to moisture.

The moisture removal unit 170 may extend along the air passage 140 . As the moisture removal unit 170 extends between the inflow path 130 and the detection unit 150, the path through which the moisture-containing dust A passes through the moisture removal unit 170 becomes longer, so that the dust can be effectively dried. can

Referring to FIG. 3 , the moisture removal unit 170 may be partially disposed on the cross-section of the flow path of the air passage 140 . Air introduced through the inflow path 130 from the outside is introduced into the air passage 140 , some of which may be introduced into the moisture removing unit 170 , and the rest of the moisture removing unit 170 is not disposed. It may flow along the air passage 140 . When the moisture removal unit 170 is disposed to be completely filled on the cross section of the flow passage of the air passage 140 , the flow of air introduced from the outside may be inhibited. Accordingly, in order to selectively introduce only the dust A including moisture into the moisture removal unit 170 , it may be preferable that the moisture removal unit 170 be disposed only partially on the flow passage cross-section of the air passage 140 .

On the cross section of the flow path of the air passage 140 , the moisture removal unit 170 may be disposed on the far side from the cover unit 120 . Specifically, the inner surface of the air passage 140 may be disposed adjacent to a surface opposite to the surface on which the cover part 120 is located.

Specifically, the dust (A) including moisture may be heavier than the relatively dry dust (B). Centrifugal force is a type of inertial force, and a particle with a large mass receives a greater centrifugal force than a particle with a small mass. Accordingly, the dust containing moisture (A) has a larger radius of rotation than the dry dust (B) and the direction of travel may be changed. That is, on the flow passage section of the air passage 140 , the dust A including moisture is highly likely to be biased toward the far side from the inflow passage 130 , and the dry dust B is biased toward the near side from the inflow passage 130 . It is highly likely to proceed. Accordingly, when the moisture removal unit 170 is disposed on the far side from the inflow path 130 , the dust A including moisture can be more effectively guided to the moisture removal unit 170 .

The moisture removal unit 170 may include a moisture absorption unit 171 , an inlet unit 173 , and an outlet unit 174 . The moisture absorbing part 171 may be filled with a moisture absorbing agent 172 therein. The desiccant 172 may be silica gel. However, the present invention is not limited thereto, and various materials may be used as the desiccant 172 .

The moisture absorption part 171 may be formed in the shape of a pipe extending along the air passage 140 . Both ends of the moisture absorption portion 171 may be blocked except for the inlet portion 173 and the outlet portion 174 .

The moisture removal unit 170 may include an inlet 173 and an outlet 174 . The inlet part 173 may be disposed on the inflow path 130 side, and the outlet part 174 may be disposed on the detection part 150 side. Part of the dust introduced into the air passage 140 through the inflow passage 130 is introduced into the moisture absorption unit 171 through the inlet portion 173, and the dust dried while passing through the moisture absorption portion 171 is transferred to the outlet portion ( 174).

The flow paths of the inlet 173 and the outlet 174 may be narrower than the flow paths of the moisture absorption unit 171 . Through this, a pressure difference between the inside and the outside of the moisture absorption part 171 is generated, and the air introduced into the moisture removal part 170 through the inlet part 173 may be smoothly diffused into the moisture absorption part 171 .

On the cross section of the flow passage of the air passage 140 , the inlet portion 173 may be disposed to be biased toward the far side from the inflow passage 130 . It may be preferable that the moisture removal unit 170 selectively accommodates only the dust A including moisture. As described above, since the dust A including moisture has a large rotation radius when the traveling direction is changed, the inlet 173 of the moisture removal unit 170 is biased toward the far side of the inflow path 130 to provide moisture. The dust (A) including the can enter the moisture removal unit 170 more effectively.

The air introduced through the inflow path 130 may have a predetermined radius and change a path. At this time, if the inlet 173 of the moisture removal unit 170 is disposed at a position overlapping the path before the path is changed, it may not be possible to smoothly introduce air into the moisture removal unit 170 . Accordingly, when the path of the air path 140 is changed, the moisture removal unit 170 may preferably extend toward the detection unit 150 from a position that does not overlap with the path before the path is changed.

5 schematically shows a partial configuration of the dust sensor 100 according to an embodiment of the present specification. 6 schematically shows a partial configuration of the dust sensor 100 according to another embodiment of the present specification.

5 and 6 schematically show a process in which dust containing moisture (A) and dry dust (B) proceed to the detection unit 150 through the second passage and the first passage formed inside the sensor 100 .

The detailed configuration of the dust sensor 100 according to an embodiment of the present specification of FIG. 5 and the dust sensor 100 according to another embodiment of the present specification of FIG. 6, which is not described below, is described in this specification according to FIGS. It may be understood that the detailed configuration of the dust sensor 100 according to the embodiment is the same.

5 and 6 , the dust sensor 100 may include a second passage 240 , 340 , a first passage 230 , 330 , a detection unit 150 , and a moisture removal unit 170 . can Here, the second passages 240 and 340 may be understood as the air passage 140 described with reference to FIGS. 1 to 4 , or may be understood as a part of the air passage 140 . The first passages 230 and 330 may be understood as the inflow passage 130 described with reference to FIGS. 1 to 4 , or may be understood as a part of the inflow passage 130 .

Alternatively, the first passages 230 and 330 may be understood as a part of the air passage 140 rather than the inflow passage 130 . In this case, a part of the air passage 140 may be the second passages 240 and 340 , and the other portion may be the first passages 230 and 330 .

The dust sensor 100 may include second passages 240 and 340 . The second passages 240 and 340 may be formed in the dust sensor 100 . The second passages 240 and 340 may mean passages through which external air flows. The second passages 240 and 340 may extend inside the dust sensor 100 . However, unlike FIGS. 5 and 6 , the second passages 240 and 340 may be formed in various shapes according to the shape and size of the dust sensor 100 .

The dust sensor 100 may include first passages 230 and 330 . The first passages 230 and 330 may communicate with the second passages 240 and 340 . Air introduced from the outside may be introduced into the second passages 240 and 340 through the first passages 230 and 330 .

The second passages 240 and 340 and the first passages 230 and 330 may communicate with each other so that when dust enters the second passages 240 and 340 from the first passages 230 and 330, the traveling direction is changed. . For example, as shown in FIG. 5 , the second passage 240 and the first passage 230 may communicate by forming a predetermined angle a. 1 to 4, it can be understood that the angle (a) is approximately 90 degrees. However, the present invention is not limited thereto, and as shown in FIG. 6 , the first passage 330 and the second passage 340 may communicate with each other while forming an approximately curved path.

In the case of FIG. 5 , since the boundary portion between the first passage 230 and the second passage 240 is bent at a predetermined angle (a), the flow of dust may not be smooth in the corner portion. Furthermore, a vortex of air is formed in the corner portion, and dust may be accumulated in the corner portion. However, in the case of FIG. 6 , when the first passage 230 and the second passage 240 form an approximately curved path and communicate with each other, the air flows more smoothly from the first passage 330 to the second passage 340 . can enter.

Alternatively, a curved guide member (not shown) may be separately disposed at a portion where the first passage 230 and the second passage 240 communicate in FIG. 5 . Specifically, the guide member may be disposed at an outer portion of the rotation radius on the path of dust entering the second passage 240 from the first passage 230 . The air passage side surface of the induction member may be formed in a curved shape. Through such a guide member, it is possible to more smoothly enter the dust from the first passage 230 to the second passage (240).

One object of the present specification is to dry the dust by installing the moisture removal unit 170 at a position corresponding to the difference in the path of dust particles whose weight varies depending on the degree of moisture contained in the dust when the traveling direction is changed. will make it Accordingly, the first passages 230 , 330 and the second passages 240 and 340 are not limited to those illustrated in FIGS. 5 and 6 , and may communicate in any form as long as the path can be changed.

The dust sensor 100 may include a detection unit 150 . The detector 150 may be disposed in the first passages 230 and 330 . The detection unit 150 may measure the concentration of dust included in the air that has passed through the moisture removal unit 170 and the second passages 240 and 340 in which the moisture removal unit 170 is not disposed. From the viewpoint of an air flow path, since the detection unit 150 is disposed behind the moisture removal unit 170 , the detection unit 150 may measure the concentration of dust dried by the moisture removal unit 170 .

The dust sensor 100 may include a moisture removal unit 170 . The moisture removal unit 170 may be disposed in the second passages 240 and 340 . In more detail, the moisture removal unit 170 may be disposed between the detection unit 150 and the first passages 230 and 330 . The dust contained in the air introduced from the outside flows into the second passages 240 and 340 through the first passages 230 and 330 , and is dried while passing through the moisture removal unit 170 before entering the detection unit 150 . can be

The moisture removal unit 170 may extend along the second passages 240 and 340 . As the moisture removal unit 170 extends between the inflow path 130 and the detection unit 150, the path through which the moisture-containing dust A passes through the moisture removal unit 170 becomes longer, so that the dust can be effectively dried. can

5 and 6 , the moisture removal unit 170 may be partially disposed on the flow passage cross-section of the second passages 240 and 340 . Air introduced from the outside is introduced into the second passages 240 and 340 through the first passages 230 and 330, some of which may be introduced into the moisture removal unit 170, and the rest may be introduced into the moisture removal unit ( It may flow along the second passages 240 and 340 where 170 is not disposed.

Alternatively, the moisture removal unit 170 may be disposed to fill the flow passage cross-section of the second passages 240 and 340 . However, when the moisture removal unit 170 is disposed to be filled on the cross-section of the flow path of the second passages 240 and 340 , the flow of air introduced from the outside may be inhibited. Accordingly, it may be preferable that the moisture removal unit 170 is only partially disposed on the cross-section of the flow passages of the second passages 240 and 340 .

On the flow passage cross-section of the second passages 240 and 340 , the moisture removal unit 170 may be disposed on the far side from the first passages 230 and 330 . That is, the first passages 230 and 330 and the second passages 240 and 340 communicate with each other so that the traveling direction is changed when entering the second passages 240 and 340 from the first passages 230 and 330 . At this time, it can be understood that the moisture removal unit 170 is disposed outside the rotation radius of the dust path.

As described with reference to FIGS. 1 to 4 , since the dust A including moisture is heavier than the dry dust B, it may have a larger turning radius when the traveling path is changed. Therefore, on the flow passage cross-section of the second passages 240 and 340 , when the moisture removal unit 170 is disposed on the far side from the first passages 230 and 330 , the moisture removal unit 170 removes the dust A including moisture. can be more effectively induced.

The moisture removal unit 170 may not overlap the first passages 230 and 330 . Referring to FIG. 5 , when the air introduced through the first passage 230 enters the second passage 240 , the route may be changed with a predetermined radius. At this time, when the inlet 173 of the moisture removal unit 170 is disposed at a position that overlaps with the first passage 230 , the air introduced from the first passage 230 flows into the moisture removal unit 170 . It may not be smooth. Accordingly, it may be preferable that the moisture removal unit 170 extends toward the detection unit 150 from a position that does not overlap the first passage 230 .

From the point of view of dust, it is as follows. Dust (A) including moisture and dry dust (B) may be mixed together in the air passing through the first passages 230 and 330 . When air enters the second passages 240 and 340 from the first passages 230 and 330 , the dust A including moisture may travel with a larger radius than the dry dust B. Accordingly, dust A including moisture may flow into the moisture removal unit 170 , and dry dust B may flow into the second passages 240 and 340 where the moisture removal unit 170 is not disposed. there is.

The dust A including moisture introduced into the moisture removal unit 170 may be dried by the desiccant 172 inside the moisture absorption unit 171 . Accordingly, the dust A including moisture becomes the dust A ′ from which the moisture has been removed and may flow out from the moisture removal unit 170 . The volume may be reduced as the moisture-containing dust (A) is changed to the dehumidified dust (A'). As a result, since the dry dust B and the dehumidified dust A ′ pass through the detection unit 150 , it is possible to reduce a measurement error of the dust concentration due to the dust A including moisture.

7 illustrates a light pulse emitted by a light source of the dust sensor 100 according to an embodiment of the present specification. 8 illustrates a signal output by the light receiving unit 152 from the detection unit 150 of the dust sensor 100 according to an embodiment of the present specification. 9 illustrates a relationship between dust and a signal in the dust sensor 100 according to an embodiment of the present specification.

If there is no dust or smoke in the air passing through the air passage 140 inside the dust sensor 100 , almost all the light emitted from the light emitting unit 151 passes through the detection space 153 and the light receiving unit 152 is not disposed. A light-shielding area can be reached. In this case, the amount of light received by the light receiving unit 152 may be very small. On the other hand, if there is dust or smoke in the air passing through the air passage 140 , a part of the light emitted from the light emitting unit 151 may be scattered by the dust or smoke in the detection space 153 to be incident on the light receiving unit 152 . there is. In this case, the amount of light received by the light receiving unit 152 may increase.

As described above, the presence/absence of dust or smoke passing through the air passage 140 can be detected based on the output fluctuation of the light receiving element (or photodetector) included in the light receiving unit 152 , and also of the photodetector. The concentration of dust or smoke passing through the air passage 140 may be detected based on the output level.

The light emitting unit 151 may emit light in the form of periodic pulses as shown in FIG. 7 . The light receiving unit 152 may generate and output an electrical signal proportional to the amount of scattered light incident on the photodetector as shown in FIG. 8 .

In the photoelectric dust sensor 100 , even if there is no dust in the air passing through the air passage 140 , the light emitted from the light emitting unit 151 is diffusely reflected in the air passage 140 , and a small amount of light is transmitted to the light receiving unit 152 . can be received. Accordingly, even if there is no dust, the level of the output signal of the photo detector has a constant value, and the photo detector is a signal whose level fluctuates in proportion to the size or volume of dust particles included in the air passing through the air passage 140 . can be printed out.

Meanwhile, the dust concentration may be defined as a total weight of dust particles included in a unit volume. The scattered light incident on the light receiving unit 152 may be proportional to the size or volume of the dust particles included in the air passage 140 , and the level of the output signal of the photo detector may also be proportional to the volume of the dust particles. Accordingly, a level of an output signal of the photo director may increase when particles of a large volume pass through, and a level of an output signal of the photo detector may decrease when particles of a small volume pass through.

The dust sensor 100 may check a volume occupied by dust particles through an output signal and convert it into a dust concentration. By cutting the output signal of the photodetector to a threshold voltage of a predetermined level, calculating the time proportion occupied by the output signal above the threshold voltage, determining the total volume occupied by dust particles included in the air passing through the air passage 140, The dust concentration can be calculated by multiplying the density of the dust particles.

9 illustrates a relationship between dust and a signal in the dust sensor 100 according to an embodiment of the present specification.

FIG. 9 is a diagram illustrating the relationship between dust and signals in the dust sensor 100 using scattered light. The output signal of the photo detector is cut to a threshold voltage of a predetermined level to be a logic high and a logic low. The output result is shown.

The dust sensor 100 is the sum of the time lengths of the interval at which the logic high becomes logic high in the result of cutting the output signal of the photo detector by the threshold voltage for a predetermined operation time Top, for example, 5 to 30 seconds (in FIG. 5 ) T1+T2++T8), divided by the operation time (Top), to obtain the volume ratio (S) of the air passing through the air passage 140 and the dust contained in the air, and multiplying this by the density of dust particles concentration can be found.

Since the volume of air injected during the operation time Top can be known and the total volume of dust particles included in the air injected during the operation time Top can be known from the output signal, The volume ratio can be calculated.

10 is a graph showing the dust concentration according to time measured by the dust sensor 100 according to an embodiment of the present specification. 11 is a graph showing the dust concentration over time measured by the dust sensor 100 according to the prior art.

When the humidity is high, there may be a large difference between the dust concentration measured using a standard measuring device and the dust concentration measured using the dust sensor 100 according to the related art. Referring to FIG. 11 , on a foggy day, it can be seen that the measurement deviation between the dust concentration measured using a standard measuring device and the dust concentration measured using the dust sensor 100 according to the related art is 50% or more.

In contrast to this, referring to FIG. 10 , when the dust concentration is measured with the dust sensor 100 according to the present specification, the dust concentration and measurement deviation measured using a standard measuring device even in a time of high humidity are reduced to within 10%. it can be seen that

As described above, when the dust passes through the moisture removal unit 170 before the dust passes through the detection unit 150 like the dust sensor 100 according to the embodiment of the present specification, the measurement error of the dust concentration due to moisture is significant. It can be confirmed that the following decrease.

Any or other embodiments of the present specification described above are not mutually exclusive or distinct. Any of the above-described embodiments or other embodiments of the present specification may be combined or combined with each configuration or function.

For example, it means that configuration A described in a specific embodiment and/or drawings may be combined with configuration B described in other embodiments and/or drawings. That is, even if the coupling between the components is not directly described, it means that the coupling is possible except for the case where it is described that the coupling is impossible.

The above detailed description should not be construed as restrictive in all respects and should be considered as illustrative. The scope of the present specification should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present specification are included in the scope of this specification.

100: dust sensor 110: housing
111: first housing 112: second housing
120: cover 130: inflow path
140: air passage 150: detection unit
151: light emitting unit 152: light receiving unit
153: detection space 154: maze part
160: fan unit 170: moisture removal unit
171: moisture absorption unit 172: moisture absorbent
173: inlet 174: outlet
181: first coupling member 182: second coupling member
230, 330: first passage 240, 340: second passage

Claims (10)

In the dust sensor for measuring the concentration of dust in the air,
a first passage formed inside the dust sensor;
a second passage formed inside the dust sensor and communicating with the first passage;
a detection unit disposed in the second passage; and
and a moisture removal unit disposed in the second passage and disposed between the detection unit and the first passage. According to claim 1,
The moisture removal unit extends along the second passage,
The moisture removing part is a dust sensor disposed on a portion of the flow passage cross-section of the second passage. 3. The method of claim 2,
The first passage and the second passage communicate with each other so that the traveling direction is changed when the dust enters the second passage from the first passage,
On the flow passage cross-section of the second passage, the moisture removing unit is disposed on the far side from the first passage. According to claim 1,
The moisture removal unit includes a moisture absorption unit filled with a desiccant therein, an inlet unit disposed at the second passage side, and an outlet unit disposed at the detection unit side. 5. The method of claim 4,
The flow path of the inlet part and the outlet part is formed to be narrower than the flow path of the moisture absorption part. 6. The method of claim 5,
On the flow passage cross-section of the second passage, the inlet portion is disposed to be biased toward the far side from the first passage. According to claim 1,
The dust sensor does not overlap the moisture removal unit with the first passage. In the dust sensor for measuring the concentration of dust in the air,
a housing including an air passage formed in a concave shape on one surface;
a cover portion coupled to the outside of the housing and covering the air passage;
a detection unit disposed in the air passage; and
and a moisture removal unit disposed on the air passage,
The cover part includes an inlet for communicating the air passage with the outside,
The moisture removal unit is a dust sensor disposed between the detection unit and the inflow path. 9. The method of claim 8,
The moisture removal unit extends along the air passage,
The moisture removal unit is a dust sensor disposed on a portion of the flow passage cross-section of the air passage. 10. The method of claim 9,
The inflow path is formed through the cover portion,
On the cross section of the flow path of the air passage, the moisture removal unit is a dust sensor disposed on the far side from the cover unit.

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