JP7103757B2 - Filtration device - Google Patents

Description

The present invention relates to a filtration device.

A filtration device equipped with a filter medium is used to purify the air by removing fine particles such as dust in the air. The filter medium is composed of, for example, a fibrous body having a plurality of fibers. The filter medium is arranged in the middle of the air passage in the filtration device, and when the air taken into the device passes through the filter medium, dust and the like collide with the fibers, so that fine particles are removed from the air. Will be done. The fine particles collected in the filter medium gradually accumulate in the filter medium as the filtration device operates, and the air flow path gradually narrows, increasing the pressure loss. When the pressure loss reaches a predetermined upper limit value (final pressure loss), it is replaced with a new filter medium as it has reached the end of its life.

In the above filtration device, fine particles are likely to be deposited near the surface of the filter medium, and surface filtration is likely to occur. Therefore, the amount of fine particles collected in the filter medium (hereinafter, also referred to as the amount of dust retention) before reaching the final pressure loss is small, and the life tends to be shortened. In particular, when filtration is performed in an environment where the concentration of fine particles having a small particle size such as PM2.5 and PM10 is high, surface filtration is likely to occur, and the life is further shortened. For this reason, there is a problem that the frequency of replacement of the filter medium increases, and the cost or labor of work increases.

By the way, conventionally, a device including a means for passing a gas containing fine particles through a filter layer and a movement control means for controlling the movement of the filter layer in a direction intersecting the passage direction of the gas has been proposed ( Patent Document 1). According to Patent Document 1, the rotation of the filter layer causes the collected fine particles to aggregate, and the centrifugal force acting on the aggregated particles increases, so that the particles are separated from the filter layer and the life of the filter is improved. Have been described.

Japanese Unexamined Patent Publication No. 2015-202425

However, the longer the life of the filter medium is, the more preferable it is, and there is a constant demand for a longer life.

An object of the present invention is to provide a filtration device having a high effect of improving the life.

As described above, Patent Document 1 describes that centrifugal force acts on the fine particles collected in the filter layer to separate the particles from the filter layer. By the way, since the centrifugal force increases as the filter medium rotates faster, it is considered that the particles can be moved in the filter medium by rotating the filter medium faster. However, the study of the present inventor has revealed that even if the rotation speed of the filter medium is adjusted, such an action may not always be obtained. As a result of further studies, the present inventor adopts a filter medium having a filling rate within a specific range, and by adjusting the rotation speed of the filter medium on the filter medium, the collected fine particles move in the filter medium. We found that it became easier and completed the present invention.
That is, one aspect of the present invention is a filtration device.
A filter medium that collects fine particles in gas,
A drive device for rotating the filter medium and
An outer frame that surrounds the filter medium from the outer peripheral side and rotates integrally with the filter medium is provided.
The filling rate of the filter medium is less than 0.05.
The drive device rotates the filter medium at a rotation speed of 1000 rpm or more so that the fine particles collected in the filter medium move in a direction away from the center of rotation of the filter medium.
The outer frame has a cylindrical guide portion extending in a direction parallel to the rotation center line of the filter medium and extending in a circumferential direction around the rotation center line, and the filter medium has the guide portion. It is characterized in that it is arranged on the inner peripheral side of .

The ratio of the radius of the filter medium to the thickness of the filter medium along the direction of the air flow is preferably 0.1 or more.

The average fiber diameter of the filter medium is preferably more than 10 μm and 100 μm or less.

The filling rate is preferably constant from the position of the filter medium passing through the center of rotation to the position of the end portion of the filter medium away from the center of rotation.

It is preferable that the guide portion is in close contact with the filter medium on the outer side in the radial direction of the filter medium orthogonal to the direction of the air flow .
The filter medium has a central portion where the center of rotation is located and an outer peripheral portion of the filter medium on the outer peripheral side of the central portion.
It is preferable that the fine particles collected in the filter medium move so that the rotation of the filter medium causes a difference in the amount of fine particles collected in the filter medium between the central portion and the outer peripheral portion.
It is preferable that the filter medium is not penetrated by the rotating shaft of the driving device that rotates the filter medium.

The filtration device of the present invention has a high effect of improving the life.

It is an exploded perspective view which shows the filtration apparatus by an example of this embodiment. It is sectional drawing along the airflow direction of a filtration device. (A) is a diagram conceptually explaining fine particles deposited on a filter medium when a conventional filtration device is used, and (b) is a diagram for using a filtration device of an example of the present embodiment. It is a figure which conceptually explains the fine particles deposited in. It is a figure which shows another example of the filtration apparatus of this embodiment.

Hereinafter, the filtration device of this embodiment will be described.

FIG. 1 is an exploded perspective view showing a filtration device 1 according to an example of the present embodiment. FIG. 2 is a cross-sectional view of the filtration device 1 of FIG. 1 along the airflow direction X.
The filtration device 1 includes a filter medium 22 and a drive device 40.

The filter medium 22 is a member that collects fine particles such as dust in a gas.
As the filter medium 22, for example, a medium-performance filter or a filter medium having filter performance as a filter for coarse dust is used. The medium-performance filter is an air filter having a medium particle collection rate mainly for particles having a particle size of less than 5 μm, and the collection efficiency measured by the colorimetric method is 50 to 95%, or the particle size is 0. It is an air filter having a collection efficiency of 50 to 95% measured by a counting method using particles of .7 μm. The coarse dust filter is an air filter mainly used for removing dust having a particle size of 5 μm or more, and the collection efficiency measured by a counting method using particles having a particle size of 0.7 μm is less than 5 to 50%. It is a filter.
The filter medium 22 is, for example, a fiber body composed of glass fiber, organic fiber, metal fiber, ceramic fiber, or a mixed fiber of two or more kinds of these, and is, for example, a non-woven fabric or felt. The form of the filter medium 22 is, for example, a sheet shape, a mat shape, or a pleated shape. The pleated filter medium 22 is produced by processing (pleating) a sheet-shaped filter medium into a zigzag shape in which mountain folds and valley folds are alternately repeated. The filter medium 22 made of glass fiber is produced, for example, by making paper by a wet method or a dry method. The filter medium 22 made of organic fibers is produced by, for example, a spunbond method, a melt blow method, a thermal bond method, a chemical bond method, or the like.

The filling rate of the filter medium 22 is less than 0.05. It was clarified that when the filling rate is within this range, the rotation speed of the filter medium 22 is appropriately adjusted so that the fine particles collected in the filter medium 22 can easily move in the filter medium 22. In the present specification, the filling rate of the filter medium 22 means the ratio of the collectors constituting the filter medium 22 to the filter medium 22, and is calculated according to the following formula.
Filling rate = volume of collector (m ³ ) / volume of filter medium 22 (m ³ )
This equation is equivalent to the following equation.
Filling rate = {1-Volume of voids contained in filter medium 22 (m ³ )} / Volume of filter medium 22 (m ³ )
Examples of the collector include a fibrous body, a porous body and a structure described later. When the collector is a fibrous body, the filling rate can be calculated by the following formula.
Filling rate = volume of fibers constituting the filter medium 22 (m ³ ) / volume of the filter medium 22 (m ³ )
= Fiber texture (g / cm ² ) / {Fiber density (g / cm ³ ) x Fiber thickness (cm)}
The thickness of the fiber body means the length of the filter medium 22 in the airflow direction.

When the filling rate of the filter medium 22 exceeds 0.05, the fine particles collected in the filter medium 22 are difficult to move to the outer peripheral side of the filter medium 22 due to the centrifugal force generated by the rotation of the filter medium 22.
The filling rate of the filter medium 22 is preferably 0.01 or less, and more preferably 0.005 or less so that the fine particles collected in the filter medium 22 can be easily moved to the outer peripheral side. The lower limit of the filling rate is, for example, 0.0001 from the viewpoint of preventing fine particles from leaking to the downstream side without being collected.
It is preferable that the filling rate of the filter medium 22 is constant from the position passing through the rotation center described later to the position of the end portion (outer peripheral portion) of the filter medium 22 away from the rotation center, that is, having no distribution.

The average fiber diameter of the filter medium 22 is, for example, 5 to 100 μm, but is preferably more than 10 μm and 100 μm or less. When the average fiber diameter exceeds 10 μm, the effect of improving the collection efficiency can be obtained by using a thick filter medium having a low collection efficiency. Further, it is possible to suppress the increase width of the pressure loss that increases due to the rotation of the filter medium 22.

The basis weight of the filter medium 22 is, for example, 30 to 500 g / m ² .
The thickness of the filter medium 22 is, for example, 1 to 60 mm. The thickness of the filter medium 22 means the length of the filter medium 22 along the airflow direction X in the examples shown in FIGS. 1 and 2.
The radius of the filter medium 22 is, for example, 50 to 175 mm.

According to one example, the filter medium 22 may be a porous body or a structure in addition to the above-mentioned fibrous body. The filter medium 22 which is a porous body is, for example, a sintering filter formed by sintering powder or fiber of metal, carbon or the like. The filter medium 22 as a structure is a honeycomb filter having a shape in which a large number of gas passages extending in one direction are arranged in a direction crossing the passages.

The filter medium 22 may have a filling rate gradient. For example, in the filter medium 22, the filling rate may change stepwise or continuously from the rotation center line Z toward the outer peripheral side. From the viewpoint of facilitating the movement of the fine particles collected in the filter medium 22 toward the outer peripheral side in the filter medium 22 as the filter medium 22 rotates, the gradient of the filling rate of the filter medium 22 is directed from the rotation center line Z to the outer peripheral side. It is preferable that the temperature is low.

According to one example, the filter body 20 may have a plurality of filter media 22. The plurality of filter media 22 are laminated, for example, in the airflow direction X, or arranged in a direction around the rotation center line Z (hereinafter, also referred to as a circumferential direction) or in the radial direction of the filter body 20 without a gap. The plurality of filter media 22 may have the same filling rate, or at least a part of the filter media 22 may be different from each other. For example, as the above-mentioned filter medium in which the gradient of the filling rate is gradually lowered from the rotation center line Z toward the outer peripheral side, a plurality of filter media 22 having different filling rates are provided without gaps in the radial direction of the filter body 20. Examples of the filter media located on the outer peripheral side are arranged so that the filling rate becomes smaller as the filter medium is located on the outer peripheral side.

The ratio of the radius of the filter medium 22 to the thickness is preferably 0.1 or more. When the ratio of the radius of the filter medium 22 to the thickness of the radius is 0.1 or more, the effect of increasing the dust retention amount increases. Further, when the space in the airflow direction in which the filtration device 1 is installed is limited, the ratio of the radius of the filter medium 22 to the thickness is preferably 1 or more, more preferably 2 or more.
The filter medium 22 has a disk-like shape in the examples shown in FIGS. 1 and 2.

As shown in the drawing, the filter medium 22 is preferably not penetrated by the rotating shaft 42, which will be described later, in that the area of the filter medium can be increased.

The drive device 40 has a rotation shaft 42 connected to an outer frame 24 described later, a motor 44 for rotating the rotation shaft 42, and a control device 60. The motor 44 rotationally drives the outer frame 24 by supplying an external or internal power source (not shown). The filter medium 22 is arranged in the outer frame 24 and is held by the outer frame 24 so that the filter medium 22 rotates integrally with the outer frame 24. Therefore, the rotation speed of the motor 44 is equal to the rotation speed of the filter medium 22. The motor 44 is supported by a plurality of supports 12 with respect to the housing 10, and the rotation shaft 42 is arranged so as to be located on the rotation center line Z described later. In FIG. 2, the support 12 of the motor 44 is not shown. The control device 60 has a control circuit designed so that the motor 44 rotates at a specified rotation speed. The rotation speed of the motor 44 can be adjusted by changing the voltage or frequency of the power supply supplied to the drive device 40 by using, for example, an inverter or a slidac.

The drive device 40 rotates the filter medium 22 at a rotation speed adjusted according to the range of the filling rate so that the fine particles collected in the filter medium 22 move toward the outer peripheral side (direction away from the rotation center of the filter medium 22). .. By rotating the filter medium 22 at such a rotation speed, the fine particles collected in the filter medium 22 can be easily moved to the outer peripheral side in the filter medium 22 and deposited on the outer peripheral portion of the filter medium 22. , As described below, the dust retention amount of the filter medium 22 can be increased. The rotation speed of the filter medium 22 adjusted according to the range of the filling rate means that when the filling rate of the filter medium 22 is less than 0.05, the fine particles collected in the filter medium 22 are on the outer peripheral side of the filter medium 22. The number of revolutions that makes it easier to move. The center of rotation of the filter medium 22 is on the center line Z of rotation. The rotation center line Z is a virtual line parallel to the airflow direction X.

As shown in the drawing, the drive device 40 is preferably arranged in the space 10a of the housing 10 on the downstream side of the filter body 20. That is, the filter medium 22 is preferably arranged on the upstream side with respect to the rotating shaft 42. According to such an arrangement mode, it is not necessary to penetrate the filter medium 22 by the rotating shaft 42, and the filter medium area can be secured. Further, it is possible to prevent a gap from being formed between the filter medium 22 and the rotating shaft 42 due to the action of centrifugal force on the filter medium 22. Further, it is possible to prevent the drive device 40 from being contaminated by the fine particles in the air and causing a problem in the rotary drive. However, according to one example, the drive device 40 may be arranged on the upstream side with respect to the filter body 20. In this case, the rotating shaft 42 penetrates the filter medium 22 and is connected to the outer frame 24.

Here, the dust retention amount of the filter medium 22 will be described with reference to FIG. FIG. 3A is a diagram conceptually explaining fine particles deposited on the filter medium when a conventional filtration device is used, and FIG. 3B is a diagram for explaining the fine particles deposited on the filter medium conceptually, and FIG. 3B is a filter medium 22 when the filtration device 1 is used. It is a figure which conceptually explains the fine particles deposited in.
In the conventional filtration device, the filter medium does not rotate, and as shown in FIG. 3A, fine particles tend to be deposited on the portion near the surface on the upstream side of the filter medium. Therefore, surface filtration is likely to occur, and the pressure loss increases in a short time. Therefore, even if a large area where fine particles can be collected (uncollected area) remains near the surface on the downstream side of the filter medium, it is necessary to replace the filter medium. In FIG. 3, the fine particles collected in the filter medium are conceptually represented by a large number of circles.
On the other hand, in the filtration device 1 of the present embodiment, the fine particles collected in the filter medium 22 receive the centrifugal force generated by the rotation of the filter medium 22 and move to the outer peripheral side of the filter medium 22, as shown in FIG. 3 (b). As shown, it is deposited on the outer peripheral portion of the filter medium 22. Therefore, at least in the central portion passing through the rotation center of the filter medium 22, surface filtration is unlikely to occur and the pressure loss is unlikely to increase, so that the time until the final pressure loss is reached is extended. Then, since the fine particles can be deposited from the outer peripheral portion of the filter medium 22 and the fine particles can be held in a wider area in the filter medium 22, the uncollected area remaining in the filter medium 22 until the final pressure loss is reached is small, and the amount of dust retained is large. In addition, the life of the filter medium 22 is extended. The amount of dust retained refers to the weight of fine particles collected on the filter medium from the start of use until the final pressure loss is reached.

On the other hand, when the filling rate of the filter medium is 0.05 or more, even if the filter medium 22 is rotated at high speed, it is difficult for the fine particles collected in the filter medium to move to the outer peripheral side, and the filtration device 1 of the present embodiment The time required to reach the final pressure loss is shorter than that in the case of using. Further, as in the case of using the filtration device 1 of the present embodiment, the amount of fine particles deposited in the filter medium 22 does not increase, the effect of increasing the amount of dust retention is suppressed, and the extension of life is small.
In the present embodiment, when the filling rate of the filter medium 22 is 0.05 or more, the rotation speed of the filter medium 22 is appropriately adjusted, so that the collected particles are moved to the outer peripheral side by centrifugal force as described above. Easy to move. Therefore, it takes a long time to reach the final pressure loss, and the amount of dust retained is increased, so that the life is extended. According to the filtration device 1 of the present embodiment, when the filtration device 1 is used in an environment where the concentration of fine particles having a small particle size such as PM2.5 and PM10 is high, it is possible to suppress an increase in the frequency of replacement of the filter medium 22. Further, even if the filter medium has a short life when used in a conventional filtration device, the life can be extended if the filling rate is within the above range and the rotation speed is appropriately adjusted. In the filtration device 1 of the embodiment, it is not necessary to use a high-performance filter medium having high collection efficiency and low pressure loss.

The rotation speed of the filter medium 22 adjusted according to the above range of the filling rate is, specifically, 1000 rotations / minute or more, and 1500 rotations / minute or more in that the effect of greatly extending the life can be obtained. It is preferably 2000 rpm or more. The upper limit of the number of revolutions is not particularly limited, but is, for example, 5000 revolutions / minute.

According to the filtration device 1 of the present embodiment, as described above, the amount of fine particles collected in the central portion and the outer peripheral portion of the filter medium is increased by moving the fine particles collected in the filter medium 22 to the outer peripheral side. There is a difference. The central portion of the filter medium 22 refers to a portion from the center of rotation of the filter medium 22 to a position separated from the outer peripheral side by a length of 50% or less (preferably 25%) of the radius of the filter medium 22. On the other hand, the outer peripheral portion of the filter medium 22 refers to a portion from the outer peripheral edge of the filter medium 22 to a length of less than 50% (preferably 25%) of the radius of the filter medium 22 and a position close to the center of rotation.

The filtration device 1 preferably further includes a housing 10, an outer frame 24, a wall member 30 (see FIG. 2), and a fan 50. In FIG. 1, the wall member 30 is not shown.

The housing 10 has a space 10a through which gas is taken in and passed. In the illustrated example, the housing 10 is a cylindrical member, and the upstream side and the downstream side in the airflow direction X are open. The airflow direction X is the direction in which the gas passes through the space 10a of the housing 10. According to one example, the housing 10 may be a duct installed in the building.

The outer frame 24 is arranged in the space 10a with a gap between it and the inner wall of the housing 10, and rotates around the rotation center line Z. The length of the gap (distance between the outer frame 24 and the inner wall of the housing 10) is, for example, 2 mm or less.

In the illustrated example, the outer frame 24 has a guide portion 25, an annular wall portion 26, and a support portion 27, which are integrally formed.

The guide portion 25 is a portion that surrounds the outer peripheral portion of the filter medium 22 from the outer peripheral side thereof. In the example shown in FIG. 2, the guide portion 25 has a cylindrical shape extending in the direction parallel to the airflow direction X and extending in the circumferential direction. The filter medium 22 is arranged on the inner peripheral side of the guide portion 25 in a state of being compressed in the radial direction, or the outer peripheral portion is adhered to the inner wall of the guide portion 25 and is arranged without a gap with respect to the guide portion 25. I'm in contact. The guide portion 25 has a function of preventing the air that has entered the filter medium 22 and flowing in the filter medium 22 on the outer peripheral side from flowing out into the gap G, and guides the air to the downstream side in the airflow direction X. The guide portion 25 is separated from the housing 10 with a gap.

The guide portion 25 preferably does not have a through hole. As a result, it is possible to prevent the fine particles collected in the filter medium 22 from passing through the through holes and flowing out into the gap between the guide portion 25 and the inner wall of the housing 10 to contaminate the downstream side. However, according to one example, the guide portion 25 may have a through hole. The guide portion 25 may have, for example, a mesh-like shape in which a large number of through holes are arranged. By providing such a through hole in the guide portion 25, the fine particles collected in the filter medium 22 can be taken out to the outer peripheral side of the filter body 20 by passing through the guide portion 25. As a result, the filter medium 22 can be used for a longer period of time. In this case, a container or the like for receiving the fine particles discharged from the filter medium 22 is arranged in the housing 10, for example, on the downstream side of the guide portion 25.

The annular wall portion 26 is a portion extending toward the rotation center line Z so as to be in contact with the filter medium 22 from the downstream side. In the illustrated example, the annular wall portion 26 has an annular shape extending from the downstream end of the guide portion 25 toward the rotation center line Z and extending in the circumferential direction.

The support portion 27 is a portion connected to the central portion of the outer frame 24 through which the rotation center line Z passes and the annular wall portion 26 so as to be in contact with the filter medium 22 from the downstream side. The support portions 27 are preferably provided in a plurality of two, three, or four or more, and are preferably arranged so as to extend radially from the central portion of the outer frame 24 as shown in the figure. The support portion 27, together with the annular wall portion 26, prevents the filter medium 22 from coming off from the outer frame 24 to the downstream side. Further, since the plurality of support portions 27 are arranged at intervals in the circumferential direction, the flow rate of air passing through the filter medium 22 is secured.

The outer frame 24 and the filter medium 22 constitute the filter body 20. According to one example, the filter body 20 does not have to include the outer frame 24 described above. In this case, the filter medium 22 is penetrated through the rotating shaft 42, which will be described later, and is fixed so as to rotate integrally with the rotating shaft 42.

According to one example, the filter body 20 may have a plurality of filter media 22. The plurality of filter media 22 are stacked, for example, in the airflow direction X, or arranged in a direction around the rotation center line Z (hereinafter, also referred to as a circumferential direction) without a gap.

The wall member 30 is a member that forms a passage 30a that throttles the flow rate of the gas taken into the housing 10. In the example shown in FIG. 2, the wall member 30 is attached to the upstream end of the housing 10 and is located upstream of the filter medium 22 arranged in the housing 10. The wall member 30 is welded to the housing 10 or connected via a sealing member such as packing, and is attached to the housing 10 without a gap. In the example shown in FIG. 2, the wall member 30 has a first wall portion 32 and a second wall portion 34.

The first wall portion 32 is an annular portion extending from the upstream end of the housing 10 to the inner peripheral side and extending in the circumferential direction. The first wall portion 32 has a wall surface 32a extending from the inner wall of the housing 10 to the end demarcating the passage 30a so as to block the flow of air to the side (upstream side) opposite to the airflow direction X. There is. In the example shown in FIG. 2, the passage 30a has a circular cross section in the direction orthogonal to the airflow direction X, and its flow path area is smaller than the cross-sectional area of the space 10a in the housing 10. In the present embodiment, the fine particles collected on the filter medium 22 easily move to the outer peripheral side and are deposited from the outer peripheral portion of the filter medium 22. Therefore, by inducing the airflow passing through the filter medium 22 to the central portion of the filter medium 22, the effect of suppressing the occurrence of surface filtration and preventing clogging is improved. In the above-mentioned conventional filtration device in which the filter medium does not rotate, fine particles are deposited from the portion on the upstream side in the thickness direction of the filter medium, so that surface filtration is likely to occur and the air flow is easily obstructed, and the filter medium is easily clogged. The wall surface 32a is a smooth surface having no dents or through holes. Further, the wall surface 32a extends in a direction intersecting the airflow direction X, and in the illustrated example, extends in a direction orthogonal to the airflow direction X. The wall surface 32a is preferably arranged close to the filter medium 22 so that the air passing through the passage 30a enters the central portion of the filter medium 22. From this point, the distance between the wall surface 32a and the filter medium 22 along the airflow direction X is set to, for example, 30 mm or less.

The radial length of the first wall portion 32 (one of both sides in the radial direction) is 5 of the inner diameter of the housing 10 from the viewpoint of guiding air to the central portion of the filter medium 22 without excessively reducing the ventilation amount. The length is preferably ~ 25%.

In the example shown in FIG. 2, the second wall portion 34 is a cylindrical portion extending upstream from the inner peripheral end of the first wall portion 32 along the airflow direction X. According to one example, the second wall portion 34 is not limited to such a form, and may have a cylindrical shape extending from the outer peripheral side end of the first wall portion 32 to the upstream side.

Further, according to an example, the shape of the first wall portion 32 is a truncated cone shape that is inclined with respect to the airflow direction X so as to continuously expand the passage 30a from the end on the inner peripheral side to the upstream side. There may be.
FIG. 4 is a diagram showing a filtration device 1 according to another example of the present embodiment.
In the example shown in FIG. 4, the inner wall of the second wall portion 34 is provided with a screw thread 34a extending in a spiral shape. In the filtration device 1 of the present embodiment, since the flow rate is throttled by the passage 30a, the ventilation amount is likely to decrease as compared with the case where the wall member 30 is not provided. However, in the filtration device 1 provided with the wall member 30 of the form shown in FIG. 4, the central portion of the passage 30a is housed while supplying air so as to flow in the direction indicated by the arrow shown along the screw thread 34a. By ensuring the flow of the airflow returning from the inside of the 10 to the upstream side, the degree of decrease in the ventilation amount can be suppressed.

The fan 50 takes in air containing fine particles and generates an air flow that passes through the housing 10. In the illustrated example, the fan 50 is connected to the rotating shaft 42 and is rotationally driven by the driving device 40. In the illustrated example, since the filter body 20 and the fan 50 are integrally rotationally driven by the drive device 40, power consumption can be suppressed as compared with the case where the filter body 20 and the fan 50 are rotationally driven by different drive devices. Can be done.

According to the filtration device 1 described above, since the filling rate of the filter medium 22 is less than 0.05, the fine particles collected in the filter medium 22 are collected in the filter medium 22 by appropriately adjusting the rotation speed of the filter medium 22. Makes it easier to move. Therefore, it takes a long time to reach the final pressure loss, and the amount of dust retained is increased, so that the life is extended.

The filtration device 1 of the present embodiment can be suitably used as a dust collector or the like that takes in and purifies the air in which the dust floats in a place where dust is likely to be generated indoors or outdoors. For example, in a work site where oil mist is likely to be generated, a work site where cutting or the like is performed, a room equipped with a cooking facility, etc., a filtration device 1 is installed, or a duct provided inside a building in contact with the room is used as a housing for filtration. The device 1 can be installed. In this case, in order to prevent the oil collected in the filter medium 22 from accumulating in the filter medium 22, water vapor is generated on the upstream side of the filtration device 1 and taken into the housing 10 together with the oil mist to prevent the filter medium 22 from accumulating. The oil collected in the filter medium 22 can be easily separated from the fibers of the filter medium 22.
Further, for example, the filtration device 1 can be installed indoors or outdoors where metal powder such as fume or other powder is likely to be generated, and welding, cutting, or the like is performed.

The filtration device 1 of the present embodiment is not limited to the case where the horizontal direction is the airflow direction X, and the vertical direction can also be the airflow direction X. For example, a duct extending in the vertical direction provided inside the building in contact with the ceiling can be used as the housing.

(Experimental example)
In order to confirm the effect of the present invention, in the filtration device of the above embodiment, the dust retention amount was measured at various different rotation speeds.
As the filter medium, a non-woven fabric made of organic fibers (PET fiber non-woven fabric DS600 manufactured by Nippon Inorganic Co., Ltd.) was used in which three layers were stacked. This filter medium had a basis weight of 0.013 g / cm ² , a fiber density of 1.38 g / cm ³ , and a thickness of 20 cm, and the filling rate of the filter medium was 0.047%.
The test method was carried out in accordance with JIS B 9908: 2011. It ended when the final pressure loss reached 498 Pa, and the dust retention amount (g / unit) per air filter was calculated. The dust retention amount was calculated from the difference between the masses of the filter media before and after the test.
In addition, as the collection efficiency, the mass method particle collection rate (%) was determined in accordance with JIS B9908 format 3.
The results are shown in Table 1.

From the comparison between Experimental Example 1 and Experimental Examples 2 and 3, it was confirmed that when the filling rate of the filter medium was less than 0.05, the dust retention amount was increased by adjusting the rotation speed. When the filling rate of the filter medium is less than 0.05, the rotation speed is adjusted so that the fine particles collected in the filter medium can easily move to the outer peripheral side, and as a result, the uncollected area of the filter medium is reduced. , It is considered that the amount of dust retained has increased.

From Experimental Examples 1 to 3, it was confirmed that when the filling rate of the filter medium was less than 0.05, the dust retention amount changed by adjusting the rotation speed.
Further, from the comparison of Experimental Examples 1 to 3, it was confirmed that the collection efficiency increases as the rotation speed increases.

Although the filtration device of the present invention has been described in detail above, the filtration device of the present invention is not limited to the above-described embodiment, and various improvements and changes may be made without departing from the gist of the present invention. Of course.

1 Filtration device 12 Support 10 Housing 10a Space 20 Filter 22 Filter material 24 Outer frame 25 Guide part 26 Circular wall part 27 Support part 30 Wall member 30a Passage 32 First wall part 32a Wall surface 34 Second wall surface 34a Thread 40 Drive Device 42 Rotating shaft 44 Motor 50 Fan

Claims (7)

A filter medium that collects fine particles in gas,
A drive device for rotating the filter medium and
An outer frame that surrounds the filter medium from the outer peripheral side and rotates integrally with the filter medium is provided.
The filling rate of the filter medium is less than 0.05.
The drive device rotates the filter medium at a rotation speed of 1000 rpm or more so that the fine particles collected in the filter medium move in a direction away from the center of rotation of the filter medium.
The outer frame has a cylindrical guide portion extending in a direction parallel to the rotation center line of the filter medium and extending in a circumferential direction around the rotation center line, and the filter medium has the guide portion. A filtration device characterized in that it is arranged on the inner peripheral side of the . The filtration device according to claim 1, wherein the ratio of the radius of the filter medium to the thickness of the filter medium along the direction of the air flow is 0.1 or more. The filtration device according to claim 1 or 2, wherein the average fiber diameter of the filter medium is more than 10 μm and 100 μm or less. The filtration device according to any one of claims 1 to 3, wherein the filling rate is constant from the position of the filter medium passing through the center of rotation to the position of the end portion of the filter medium away from the center of rotation. The filtration device according to any one of claims 1 to 4, wherein the guide portion is in contact with the filter medium without a gap on the outside in the radial direction of the filter medium orthogonal to the direction of the air flow . The filter medium has a central portion where the center of rotation is located and an outer peripheral portion of the filter medium on the outer peripheral side of the central portion.
Claims 1 to 5, wherein the rotation of the filter medium causes the fine particles collected in the filter medium to move so as to cause a difference in the amount of fine particles collected in the filter medium between the central portion and the outer peripheral portion. The filtration device according to any one item. The filtration device according to any one of claims 1 to 6, wherein the filter medium is not penetrated by a rotation shaft of a drive device for rotating the filter medium.

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