Air Quality Monitoring Device

Abstract

The present disclosure relates to an air quality monitoring device for measuring the concentrations of particulate matter and gaseous substances contained in external air. According to the present disclosure, the air quality monitoring may include: a casing having a vertical inlet duct having an inlet formed at the bottom thereof to introduce the external air thereinto; a diverting duct connected to the vertical inlet duct to change an airflow direction; a vertical outlet duct connected to the diverting duct and having an outlet formed at the bottom thereof; and a heating type humidity controller placed in the inlet of the vertical inlet duct to heat the external air, to lower the relative humidity of the external air, and to make measurement air.

Description

CROSS REFERENCE TO RELATED APPLICATION OF THE DISCLOSURE

[0001] The present application claims priority to Korean Patent Application No. 10-2023-0107666 filed in the Korean Intellectual Property Office on Aug. 17, 2023, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE DISCLOSUREField of the Disclosure

[0002] The present disclosure relates to an air quality monitoring device, more specifically to an air quality monitoring device that is capable of accurately monitoring the concentrations of particulate matter and gaseous substances in the air.Background of the Related Art

[0003] Typically, light-scattering particulate matter monitoring devices are employed to measure the concentration of particulate matter suspended in the air. These devices operate by illuminating particulate matter, receiving the scattered light from the particulate matter, and measuring the concentration of particulate matter.

[0004] FIG. 1 schematically shows the configuration of a conventional particulate matter monitoring device 10. According to the conventional particulate matter monitoring device 10, as shown, external air A enters an inlet 11a formed at the top of a casing 11, and measurement air A1 is discharged from an outlet 11b formed at the bottom of the casing 11.

[0005] An air heater 13, an air quality monitoring sensor 14, a flow meter 15, and a high-power air pump 16 are sequentially positioned along the path where the external air A flows vertically from top to bottom.

[0006] The conventional particulate matter monitoring device 10 introduces the external air A at a constant flow rate into the inlet 11a using the high-power air pump 16, whereupon the air quality monitoring sensor 14 measures the concentration of particulate matter. Before the air quality monitoring sensor 14 measures the air quality, the air heater 13 increases the temperature of external air A to decrease the relative humidity of external air A, thereby dehumidifying the hygroscopic particulate matter.

[0007] However, according to the conventional particulate matter monitoring device 10, if the temperature of external air A increases by the air heater 13, buoyancy in the opposite direction to the flowing direction of external air A is generated. The high-power air pump 16 is necessitated to enable the external air A to flow against the buoyancy that is generated in the opposite direction to the flowing direction of the external air A. The buoyancy in the opposite direction to the external air A and the use of the high-power air pump 16 significantly decrease the internal air pressure within the flow path of the external air A, thereby leading to a big expansion of external air A. The expansion of external air A may cause measurement errors for particulate matter.

[0008] The temperature of external air A heated by the air heater 13 depends on the humidity of external air A. As a result, both the buoyancy of external air A and the flow rate of external air A depend on the heat generated. However, devices that measure external pollutants such as fine particulate matter must maintain a constant flow rate of air.

[0009] Furthermore, according to Bernoulli's principle, the air pressure inside the airflow path decreases in proportion to the height of the airflow path, thereby generating rising energy in the opposite direction to the airflow. To compensate for this, the high-power air pump 16 requires additional power.

[0010] In the case of the conventional device that allows the external air to flow vertically from top to bottom, heavy dust particles may deposit on the inside of the casing 11, thus requiring regular cleaning.

[0011] Additionally, the conventional particulate matter monitoring device 10 measures only the particulate matter in the air, but cannot measure the concentrations of gaseous substances in the air.SUMMARY OF THE DISCLOSURE

[0012] Accordingly, the present disclosure has been made in view of the above-mentioned problems occurring in the related art, and it is an object of the present disclosure to provide an air quality monitoring device that can maintain a constant flow rate of air, without having a control device and a high-power air pump that serve to offset the variations in the airflow rate, which are made by the degree of temperature increased by an air heater, the speed of wind passing through an inlet, and the height of an airflow path.

[0013] It is another object of the present disclosure to provide an air quality monitoring device that can allow external air to move in the same direction as buoyancy, so that the energy to offset the buoyancy generated by the heated air is not needed anymore.

[0014] It is yet another object of the present disclosure to provide an air quality monitoring device that does not require any cleaning.

[0015] To accomplish the above-mentioned objects, according to the present disclosure, there is provided an air quality monitoring device for measuring the concentrations of particulate matter and gaseous substances in external air. According to the present disclosure, the air quality monitoring device may include: a casing having a vertical inlet duct with an inlet formed at the bottom to allow external air to flow in; a diverting duct connected to the vertical inlet duct to change the direction of airflow; a vertical outlet duct connected to the diverting duct and having an outlet formed at the bottom; and a heating type humidity controller placed in the inlet of the vertical inlet duct to heat the external air, to lower the relative humidity of the external air, and to make measurement air.

[0016] According to the present disclosure, desirably, the air quality monitoring device may further include: an air quality monitoring sensor disposed on a flow path of the measurement air passing through the heating type humidity controller to measure the concentrations of particulate matter and gaseous substances in the measurement air; and an air ventilation fan disposed inside the casing to generate a negative pressure so that the external air is introduced into the inlet and then discharged from the outlet.

[0017] According to the present disclosure, desirably, the inlet and the outlet are located at the same height as each other.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the present disclosure will be apparent from the following detailed description of the preferred embodiments of the disclosure in conjunction with the accompanying drawings, in which:

[0019] FIG. 1 is a schematic view showing a conventional particulate matter monitoring device;

[0020] FIG. 2 is a schematic view showing an air quality monitoring device according to the present disclosure;

[0021] FIG. 3 is an exemplary view showing the position of an air quality monitoring sensor of the air quality monitoring device according to the present disclosure;

[0022] FIG. 4 is an exemplary view showing a monitoring method of the air quality monitoring sensor in the air quality monitoring device according to the present disclosure;

[0023] FIG. 5 is a schematic view showing a first variation of the air quality monitoring device according to the present disclosure; and

[0024] FIG. 6 is a schematic view showing a second variation of the air quality monitoring device according to the present disclosure.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, the present disclosure is disclosed with reference to the attached drawings wherein the corresponding parts in the embodiments of the present disclosure are indicated by corresponding reference numerals.

[0026] In the entire specification, when a certain portion “comprises or includes” a certain component, this indicates that the other components are not excluded and may be further included unless specially described otherwise.

[0027] FIG. 2 is a schematic view showing an air quality monitoring device 100 according to the present disclosure. As shown, the air quality monitoring device 100 includes a casing 110 having an inlet 111a into which external air A is introduced; an outlet 115a from which measurement air A1 is discharged; a heating type humidity controller 120 placed in the inlet 111a of the casing 110 to heat the external air A, to lower the relative humidity of the external air A, and to make the measurement air A1; an air quality monitoring sensor 130 for monitoring the air quality of the measurement air A1 whose relative humidity is lowered after passing through the heating type humidity controller 120; and an air circulating fan 140 disposed inside the casing 110 to generate a negative pressure so that the external air A is introduced into the inlet 111a.

[0028] The air quality monitoring device 100 according to the present disclosure monitors both of gaseous substances and particulate matter in the external air A. The gaseous substances include ozone O3, nitrogen dioxide NO2, carbon monoxide CO, sulfur dioxide SO2, and the like. The particulate matter absorbs water and increases its particle size, and the gaseous substances are melt into water when relative humidity is greater than a given level.

[0029] According to the air quality monitoring device 100 of the present disclosure, the inlet 111a and the outlet 115a are located at the same level as each other, while being placed below the air quality monitoring sensor 130. The external air A flows from bottom to top and is then heated by the heating type humidity controller 120 so that the relative humidity of the external air A becomes lowered. The grown hygroscopic particulate matter and the melted gaseous substances are dehumidified or evaporated by the heating type humidity controller 120. After that, air quality is measured by the air quality monitoring sensor 130.

[0030] Buoyancy generated by the heating type humidity controller 120 has the same direction as the flow of measurement air A1, and accordingly, additional energy to offset the buoyancy is not needed at all, thus the measurement air A1 can flow only with the low-power air circulating fan 140.

[0031] In this case, the external air A represents the air that is introduced into the casing 110 from the outside of the casing 110 through the inlet 111a, and the measurement air A1 represents the air that flows out from the heating type humidity controller 120 after the humidity of the external air A flown into the heating type humidity controller 120 is lowered to a predetermined humidity. The measurement air A1 flows from the air quality monitoring sensor 130 to the outlet 115a.

[0032] The temperature and relative humidity of the measurement air A1 are changed by the heating type humidity controller 120, thus the measurement air A1 is differentiated from the external air A.

[0033] The casing 110 serves to support the respective components for the external air A to introduce therein, for air quality monitoring sensor 130 to monitor the quality of air, and for the air to discharge to the outside. The casing 110 includes a vertical inlet duct 111 having the inlet 111a formed at the bottom thereof to introduce the external air A therein, a diverting duct 113 connected to the vertical inlet duct 111 in such a way as to change the flowing direction of the measurement air A1; and a vertical outlet duct 115 connected to the diverting duct 113 and having the outlet 115a formed at the bottom thereof.

[0034] The vertical inlet duct 111 has the inlet 111a formed at the bottom thereof so that the external air A is guided to flow from bottom to top. The vertical outlet duct 115 has the outlet 115a formed at the bottom thereof so that the external air A is guided to flow from top to bottom.

[0035] The vertical inlet duct 111 and the vertical outlet duct 115 are desirably located vertically with respect to a horizontal plane, but they may be placed slantly within a given error range. That is, they generally extend up and down nearly perpendicular to a horizontal plane.

[0036] The diverting duct 113 connects the vertical inlet duct 111 and the vertical outlet duct 115 to allow the flowing direction of the measurement air A1 to change.

[0037] In FIG. 2, the diverting duct 113 is located horizontally, that is, parallel to the horizontal plane, but it is just exemplary. Therefore, only if the diverting duct 113 connects the vertical inlet duct 111 and the vertical outlet duct 115 to allow the flowing direction of the measurement air A1 to change, it may not be restricted to as shown in the drawings. If the diverting duct 113 is titled at an angle because the level of the area where the diverting duct 113 has a connection point with the vertical outlet duct 115 is low, the dust particles falling from the measurement air A1 can move downward, which is more preferable.

[0038] Further, the vertical inlet duct 111 and the vertical outlet duct 115 have a designated length so that the inlet 111a and the outlet 115a have the same height as each other. According to Bernoulli's principle, under the condition of the inlet 111a and the outlet 115a having the same height, the height of the flowing path and the wind speed do not affect the air pressure of flowing path so that the flow rate does not change.P+12⁢ρυ2+ρ⁢gh=constant,

[0039] The above equation is Bernoulli's principle. In this case, the P represents the air pressure inside the flowing path, ρ is the air density, v is the wind speed around the inlet, g is the gravitational acceleration, and h is the height of the flowing path (air path) from the inlet to the outlet.

[0040] The pressure inside the flowing path is lowered in proportion to the square of the wind speed around the inlet and the height of the flowing path, thus the buoyant energy of air is generated. Therefore, the conventional technology in which air flows from top to bottom requires complex devices such as a high-power air pump and a flow rate control device.

[0041] According to the present disclosure, the height h of the flowing path is 0 and the wind speed has the same effect on the inlet 111a and the outlet 115a, thus the pressure of the inlet 111a and the pressure of the outlet 115a according to the wind speed cancel each other out. That is, the wind around the inlet 111a and the outlet 115a does not change the flow rate of internal air. Further, buoyancy is generated from the air by the heating type humidity controller 120, but the buoyancy forces equally generated in the vertical inlet duct 111 and the vertical outlet duct 115, which have the same height, cancel each other out. That is, the heat generated from the heating type humidity controller 120 does not affect the flow rate of internal air.

[0042] In this case, the vertical inlet duct 111, which connects the inlet 111a, the heating type humidity controller 120, and the air quality measuring sensor 130, is desirably made of an anti-static material. The anti-static material advantageously prevents the particulate matter from being attached thereto due to static electricity. To do this, desirably, the vertical inlet duct 111 is made of a material such as polytetrafluoroethylene (PTFE) with a low friction coefficient or a material coated with an anti-static material.

[0043] Further, the vertical inlet duct 111, which connects the heating type humidity controller 120 and the air quality measuring sensor 130, desirably has internal surfaces with insulation coating or made of an insulation material. This prevents the temperature of the measurement air A1, whose relative humidity has been lowered by heating, from lowering and the relative humidity from increasing again while the measurement air A1 flows up to the air quality measurement sensor 130.

[0044] The heating type humidity controller 120 heats the external air A introduced into the inlet 111a and thus lowers the relative humidity of the external air A. The heating type humidity controller 120 fits the entire width of the vertical inlet duct 111 and heats it by contacting the external air A that flows along the vertical inlet duct 111. The heating type humidity controller 120 is provided in the form in which a hot wire is wound several times along the width of the vertical inlet duct 111 so that the contact area with the external air A increases to enable the external air A to be heated in a short period of time.

[0045] The buoyancy acts upward in the measurement air A1, that is, the external air A that is heated by and contacts with the heating type humidity controller 120. In this case, the measurement air A1 flows upward by the negative pressure generated from the air circulating fan 140 located above the heating type humidity controller 120 in accordance with the buoyancy.

[0046] Further, an external temperature and humidity sensor (not shown) can be optionally located on one side of the inlet 111a to measure the temperature and relative humidity of the external air A. The external temperature and humidity sensor transmits the measured data of temperature and relative humidity to a controller (not shown).

[0047] Furthermore, an internal temperature and humidity sensor (not shown) can be located above the heating type humidity controller 120 to measure the temperature and relative humidity of the measurement air A1 heated by the heating type humidity controller 120. The internal temperature and humidity sensor transmits the measured data of temperature and relative humidity to the controller.

[0048] FIG. 3 is an exemplary view showing the position of the air quality monitoring sensor of the air quality monitoring device according to the present disclosure, and FIG. 4 is an exemplary view showing a monitoring method of the air quality monitoring sensor of the air quality monitoring device according to the present disclosure.

[0049] As shown in FIG. 3, the air quality monitoring sensor 130 is attached on the internal surfaces of the vertical inlet duct 111 to measure the concentrations of the particulate matter and gaseous substances in the measurement air A1. The air quality monitoring sensor 130 serves to measure both the particulate matter and the gaseous substances.

[0050] The air quality monitoring sensor 130 is located along the airflow direction in the vertical inlet duct 111. That is, the measurement air A1 flows in the direction of Y-axis (in the opposite direction to gravity), and the air quality monitoring sensor 130 having an air-permeable surface 130a is arranged parallel to the direction of airflow and the plane formed by the Y-axis and Z-axis.

[0051] FIG. 4 exemplarily shows a case that the air quality monitoring sensor 130 is a light-scattering fine dust monitoring sensor to measure particulate matter. As shown in FIG. 4, the air quality monitoring sensor 130 includes a light source generator 133 and a light meter 131. The light source generator 133 and the light meter 131 are located perpendicular to the opposite direction to the gravity (that is, the Y-axis). In detail, the light source generator 133 is in the direction of X-axis, and the light meter 131 is in the direction of Z-axis.

[0052] The light source generator 133 can be a laser generator, and the light meter 131 can be a photodiode. The light source generator 133 emits laser L onto the measurement air A1 flowing vertically from bottom to top, and the light meter 131 measures the amount of light scattered by a particulate contained in the measurement air A1 and thus measures the size and number of the particulates or concentration.

[0053] If a plurality of light meters 131 are placed in the air quality monitoring sensor 130, multiple scattering lights can be acquired corresponding to the sizes of particulate matter, thereby enabling the concentration of the particulate matter to be measured according to the sizes of the particulate matter.

[0054] In this case, the measurement air A1 flows from bottom to top so that the particulate matter contained therein can deposit at the bottom but cannot deposit on the surface of the air quality monitoring sensor 130, thereby advantageously ensuring easy maintenance for the air quality monitoring sensor 130.

[0055] The air circulating fan 140 is located on top of the vertical inlet duct 111 and rotates to generate the negative pressure so that the external air A is introduced into the vertical inlet duct 111 and then moves to the outlet 115a of the vertical outlet duct 115.

[0056] According to the air quality monitoring device 100 of the present disclosure, the external air A flows from bottom to top through the inlet 111a by means of the operation of the air circulating fan 140. In this process, the external air A is heated by the heating type humidity controller 120 to become the measurement air A1, and the buoyant force acts upward on the measurement air A1 according to convection, so that the air circulating fan 140 does not require much power.

[0057] According to the present disclosure, therefore, the air circulating fan 140 is provided as a low-power air circulating fan that generates only negative pressure. In this case, a tachometer can be built in the air circulating fan 140 to measure the flow rate of the measurement air A1 flowing along the vertical inlet duct 111.

[0058] In this case, the air circulating fan 140 can be located behind the inlet 111a as well as behind the air quality monitoring sensor 130.

[0059] The air quality monitoring process using the air quality monitoring device 100 according to the present disclosure will be described with FIGS. 2 to 4.

[0060] The air quality monitoring device 100 according to the present disclosure can be installed in a place where air quality is measured. In this case, the inlet 111a and the outlet 115a are located side by side at the bottom of the casing 110. If the air circulating fan 140 rotates, the negative pressure is generated to allow the external air A to be introduced into the inlet 111a. In this case, the external temperature and humidity sensor measures the temperature and relative humidity of the external air A and transmits the measured results to the controller.

[0061] The controller (not shown) adjusts the heating intensity of a heater (not shown) of the heating type humidity controller 120 according to the amount of error obtained by subtracting predetermined reference relative humidity from the relative humidity of the measurement air A1 that is measured by the internal temperature and humidity sensor in the heating type humidity controller 120.

[0062] A method to adjust the heating intensity method can be a proportional-integral-differential control method or another control method. Generally, the greater the amount of error, the stronger the heating intensity, and if the amount of error is negative, the heater does not operate.

[0063] The external air A is introduced into the inlet 111a, and next, it moves upward along the vertical inlet duct 111. The external air A passes through the heating type humidity controller 120 and is thus heated, so that it becomes the measurement air A1. The measurement air A1, whose relative humidity is lowered, is introduced into the air quality monitoring sensor 130. After the external air A is heated, it becomes the measurement air A1. In this case, water in a liquid state in which the particulate matter is deliquesced and the gaseous substances are dissolved evaporates.

[0064] The air quality (concentration or number) of the measurement air A1 whose relative humidity is lowered is measured by the air quality monitoring sensor 130, then the measured air quality is transmitted from the air quality monitoring sensor 130 to the controller. The controller outputs the received air quality to the outside.

[0065] As shown in FIG. 2, the measurement air A1 whose air quality is measured by the air quality monitoring sensor 130 passes through the air circulating fan 140, the diverting duct 113, and the vertical outlet duct 115, sequentially; and is then discharged from the outlet 115a.

[0066] In this case, the inlet 111a and the outlet 115a are located at the bottom of the air quality monitoring device 100 at the same level as each other. As a result, the flow rate of the air remains constantly irrespective of the output of the heating type humidity controller 120. This is because the buoyancy of air acts both on the vertical inlet duct 111 and the vertical outlet duct 115. According to Bernoulli's principle, the amount of the wind effect applied to the inlet 111a and the outlet 115a are the same as each other, but the directions of the said wind effect are opposite to each other, thus the pressure of the inlet 111a and the pressure of the outlet 115a according to the wind speed cancel each other out. That is, the flow rate of the air is not interfered by the wind speed.

[0067] FIG. 5 is a schematic view showing a first variation of the air quality monitoring device according to the present disclosure. An air quality monitoring device 100a as the first variation of the present disclosure further includes an outer casing 160 adapted to prevent the air discharged from the outlet 115a from being reintroduced into the inlet 111a.

[0068] The outer casing 160 has an outer inlet 161 formed thereon at the same level as the inlet 111a. An outer outlet 163 formed thereon at a higher level than that of the outlet 115a.

[0069] The outer casing 160 and the outer outlet 163 can prevent the measurement air A1 discharged from the outlet 115a from being reintroduced into the outer inlet 161.

[0070] The measurement air A1 flows along the flow path of the casing 110, contacts with various components, and absorbs the heat generated from the components, so that the relative humidity of the measurement air A1 becomes different from the external air A. Due to the additional installation of the outer casing 160, the introduction path of the external air A is spaced apart from the discharge path of the measurement air A1 to prevent the measurement air A1 from being reintroduced into the outer inlet 161.

[0071] In some cases, further, a partition wall can be located between the outlet 115a and the inlet 111a to prevent the discharged air from being reintroduced.

[0072] Otherwise, the outlet 115a and the inlet 111a are located in the casing 110 in such a way as to face opposite directions to each other, thereby preventing the discharged air from being reintroduced.

[0073] Further, as shown in FIG. 6, an air quality monitoring device 100b as a second variation of the present disclosure is configured to allow the air moving direction to move from top to bottom so that the measurement air A1 is discharged to top. That is, the casing 110 can be turned upside down. In this case, the direction of the buoyancy of the external air A heated by the heating type humidity controller 120 is opposite to the flowing direction of the external air A, the air circulating fan 140 can be, therefore, replaced with a high-power air pump 170.

[0074] Further, a flow meter 150 is located to measure the flow rate of air.

[0075] As mentioned above, the air quality monitoring device according to the present disclosure is configured to allow the external air to flow from bottom to top. Even if the buoyancy acts on the external air by the heat of the heating type humidity controller, the buoyancy is generated in the same direction as the flowing direction of the air. Therefore, the high-power air pump used in the conventional air quality monitoring device to offset the buoyancy is not required.

[0076] As a result, advantageously, airflow is performed only by the low-power air circulating fan.

[0077] As the air flows from bottom to top, further, heavy dust, pollen grains, insects, etc fall so that impurities do not deposit on the internal surfaces of the air quality monitoring device, thereby advantageously requiring no cleaning.

[0078] Since the outlet and the inlet are formed at the the bottom of the air quality monitoring device at the same level as each other, further, the flow rate of air remains constantly irrespective of the temperature increased by the heating type humidity controller. As a result, the flow rate of air can be accurately measured only with the rotational speed of the air circulating fan, and further, the flow rate of air is not affected by the wind speed, so accurate measurement is possible.

[0079] The specific embodiments of the present disclosure have been illustrated and described.

[0080] It is obvious that persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above teachings. Although the embodiments above have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications. It is therefore intended that the scope of the disclosure be limited not by this detailed description, but rather by the claims appended hereto.

Claims

1. An air quality monitoring device for measuring the concentrations of particulate matter and gaseous substances contained in external air (A), the air quality monitoring device comprising:a casing (110) having a vertical inlet duct (111) having an inlet (111a) formed at the bottom thereof to introduce the external air (A) thereinto, a diverting duct (113) connected to the vertical inlet duct (111) to change an airflow direction, and a vertical outlet duct (115) connected to the diverting duct (113) and having an outlet (115a) formed at the bottom thereof;a heating type humidity controller (120) placed in the inlet (111a) of the vertical inlet duct (111) and making measurement air (A1) by heating the external air (A) and lowering the relative humidity of the external air (A);an air quality monitoring sensor (130) disposed in a flowing path of the measurement air (A1) passing through the heating type humidity controller (120) to measure the concentrations of particulate matter and gaseous substances in the measurement air (A1); andan air circulating fan (140) disposed inside the casing (110) in such a way as to rotate and generate a negative pressure so that the external air (A) is introduced into the inlet (111a) and then discharged from the outlet (115a).

2. The air quality monitoring device according to claim 1, wherein the air quality monitoring sensor (130) has an air-permeable surface (130a) placed parallel to the airflow direction in the vertical inlet duct (111).

3. The air quality monitoring device according to claim 2, wherein the vertical inlet duct (111) is made of an anti-static material, and the internal surfaces from the heating type humidity controller (120) to the air quality measuring sensor (130) in the vertical inlet duct (111) are coated with an insulation material.

4. The air quality monitoring device according to claim 3, wherein the air circulating fan (140) has a tachometer built therein.

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