JP2018183719A - Filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter having a high effect for improving a lifetime.SOLUTION: A filter includes a filter medium for collecting fine particles in gas, and a driving device for rotating the filter medium. A filling rate of the filter medium is less than 0.05. The driving device rotates the filter medium at a rotational frequency adjusted according to a range of the filling rate so that fine particles collected by the filter medium are moved in a direction separating from a rotation center of the filter medium.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a filtration device.

  In order to remove fine particles such as dust in the air and to clean the air, a filtering device including a filter medium is used. The filter medium is made of a fibrous body having a plurality of fibers, for example. The filter medium is arranged in the middle of the air passage in the filter device, and when the air taken into the filter passes through the filter medium, dust or the like collides with the fiber, thereby removing fine particles from the air. Is done. The fine particles collected on the filter medium are gradually deposited in the filter medium as the filter device is operated, and the air flow path gradually narrows to increase 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 reaches the end of its life.

  In the filtration device, fine particles are likely to be deposited near the surface of the filter medium, and surface filtration is likely to occur. For this reason, the amount of fine particles (hereinafter also referred to as dust holding amount) collected by the filter medium until the final pressure loss is reached is small, and the life is likely to be shortened. In particular, if filtration is performed in an environment where the concentration of fine particles having a small particle diameter such as PM2.5 or PM10 is high, surface filtration is likely to occur, and the lifetime is further shortened. For this reason, the problem that the exchange frequency of a filter medium increases and the cost or the effort of work increases has arisen.

  By the way, conventionally, there has been proposed an apparatus including means for passing a gas containing fine particles through a filter layer and movement control means for controlling movement of the filter layer in a direction intersecting the gas passage direction ( Patent Document 1). In Patent Document 1, when the filter layer rotates, the collected fine particles agglomerate and the centrifugal force acting on the agglomeration increases, so that the particles are detached from the filter layer and the life of the filter is improved. Have been described.

Japanese Patent Laying-Open No. 2015-202425

  However, the longer the life of the filter medium is, the more preferable, and a longer life is constantly demanded.

  An object of this invention is to provide the filtration apparatus with the high effect of improving a lifetime.

In Patent Document 1, as described above, it is described that the particles are separated from the filter layer by the centrifugal force acting on the fine particles collected in 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, as a result of the study by the present inventor, it has been clarified that even if the rotational speed of the filter medium is adjusted, such an effect is not always obtained. As a result of further investigation, the present inventor adopted a filter medium having a filling rate within a specific range, and then adjusted the rotational speed of the filter medium, whereby the collected fine particles moved in the filter medium. As a result, the present invention has been completed.
That is, one embodiment of the present invention is a filtration device,
A filter medium for collecting fine particles in the gas;
A drive device for rotating the filter medium,
The filling rate of the filter medium is less than 0.05,
The drive device rotates the filter medium at a rotation speed adjusted according to the range of the packing rate so that the fine particles collected by the filter medium move in a direction away from the rotation center of the filter medium. And

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

  The average fiber diameter of the filter medium is preferably more than 10 μm and not more than 100 μm.

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

  Furthermore, it is preferable to provide an outer frame surrounding the filter medium from the outer peripheral side.

  The filtration device of the present invention is highly effective in improving the life.

It is a disassembled perspective view which shows the filtration apparatus by an example of this embodiment. It is sectional drawing along the airflow direction of the filtration apparatus. (A) is a figure explaining notionally the microparticles | fine-particles deposited on the filter medium at the time of using the conventional filter apparatus, (b) is a filter medium at the time of using the filter apparatus of an example of this embodiment. It is a figure which illustrates notionally the fine particles deposited on the. It is a figure which shows another example of the filtration apparatus of this embodiment.

  Hereinafter, the filtration device of the present 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 along the airflow direction X of the filtration device 1 of FIG.
The filter 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 the gas.
For the filter medium 22, for example, a medium filter or a filter medium having filter performance as a coarse dust filter 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 has a collection efficiency of 50 to 95% measured by a colorimetric method, or a particle size of 0 This is an air filter having a collection efficiency of 50 to 95% measured by a counting method using 7 μm particles. The coarse dust filter is an air filter mainly used for removing dust having a particle diameter of 5 μm or more, and the collection efficiency measured by a counting method using particles having a particle diameter of 0.7 μm is less than 5 to 50%. It is a filter.
The filter medium 22 is, for example, a glass fiber, an organic fiber, a metal fiber, a ceramic fiber, or a fiber body made of a mixed fiber of two or more of these fibers, and is, for example, a nonwoven fabric or a felt. The form of the filter medium 22 is, for example, a sheet shape, a mat shape, or a pleat 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 spun bond 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 has been clarified that when the filling rate is within this range, the rotational speed of the filter medium 22 is appropriately adjusted so that the fine particles collected on the filter medium 22 can easily move in the filter medium 22. In this specification, the filling rate of the filter medium 22 means the ratio of the trapping material constituting the filter medium 22 in the filter medium 22 and is calculated according to the following formula.
Filling rate = volume of collected material (m ³ ) / volume of filter medium 22 (m ³ )
This equation is equivalent to the following equation.
Filling ratio = {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 structural body, which will be described later. The filling factor when the collector is a fibrous body can be calculated as in the following equation.
Filling rate = volume of fiber constituting filter medium 22 (m ³ ) / volume of filter medium 22 (m ³ )
= Fiber weight per unit area (g / cm ² ) / {Fiber density (g / cm ³ ) × Fiber body thickness (cm)}
The thickness of the fibrous 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 on 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 by the filter medium 22 can be more easily moved to the outer peripheral side. The lower limit of the filling rate is, for example, 0.0001 from the viewpoint of preventing the fine particles from being collected and leaked downstream.
It is preferable that the filling rate of the filter medium 22 is constant from a position passing through the rotation center, which will be described later, to a position of an end portion (outer periphery) 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 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 in the pressure loss that increases as the filter medium 22 rotates.

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 refers to the length of the filter medium 22 along the airflow direction X in the example illustrated in FIGS. 1 and 2.
The radius of the filter medium 22 is, for example, 50 to 175 mm.

  According to an example, the filter medium 22 may be a porous body or a structure in addition to the above-described fiber body. The filter medium 22 that is a porous body is, for example, a sintered filter formed by sintering powder or fiber such as metal or carbon. 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 passage.

  The filter medium 22 may have a filling rate gradient. For example, the filling rate of the filter medium 22 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 by the filter medium 22 to the outer peripheral side as the filter medium 22 rotates, the gradient of the filling rate of the filter medium 22 increases from the rotation center line Z toward the outer peripheral side. Is preferably low.

  According to an 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) 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 may be at least partially different. For example, as a filter medium in which the gradient of the filling rate described above gradually decreases from the rotation center line Z toward the outer peripheral side, a plurality of filter media 22 having different filling rates can be provided without gaps in the radial direction of the filter body 20, Examples of the filter medium are such that the filter medium is located closer to the outer periphery side so that the filling rate becomes smaller.

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 is 0.1 or more, the effect of increasing the amount of dust retention increases. Moreover, when the space of the airflow direction in which the filtration apparatus 1 is installed has a restriction, 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 shape in the example shown in FIGS. 1 and 2.

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

  The drive device 40 includes a rotating shaft 42 that is connected to an outer frame 24 described later, a motor 44 that rotates the rotating shaft 42, and a control device 60. The motor 44 rotates the outer frame 24 by being supplied with external or internal power (not shown). The filter medium 22 is disposed in the outer frame 24 and is held by the outer frame 24, so that it rotates integrally with the outer frame 24. For this reason, the rotation speed of the motor 44 is equal to the rotation speed of the filter medium 22. The motor 44 is supported with respect to the housing 10 via the plurality of supports 12 and is arranged so that the rotation shaft 42 is positioned on a 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 designated rotational speed. The rotation speed of the motor 44 can be adjusted by changing the voltage or frequency of the power supplied to the driving device 40 using, for example, an inverter or a slider.

  The driving device 40 rotates the filter medium 22 at a rotation speed adjusted in accordance with the range of the filling rate so that the fine particles collected by the filter medium 22 move to the outer peripheral side (direction away from the rotation center of the filter medium 22). . By rotating the filter medium 22 at such a rotational speed, the fine particles collected by the filter medium 22 can be easily moved to the outer peripheral side in the filter medium 22 and deposited on the outer periphery of the filter medium 22. As described below, the amount of dust retained in the filter medium 22 can be increased. The number of rotations 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 rotations that makes it easier to move. The rotation center of the filter medium 22 is on the rotation center line Z. The rotation center line Z is a virtual line parallel to the airflow direction X.

  As shown in the figure, the driving device 40 is preferably disposed on the downstream side of the filter body 20 in the space 10 a of the housing 10. In other words, the filter medium 22 is preferably arranged on the upstream side with respect to the rotation shaft 42. According to such an arrangement mode, it is not necessary to pass the filter medium 22 through 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 rotary shaft 42 and the centrifugal force acting on the filter medium 22. In addition, it is possible to prevent the drive device 40 from being contaminated by fine particles in the air and causing problems in rotational drive. However, according to an example, the drive device 40 may be disposed upstream of the filter body 20. In this case, the rotating shaft 42 passes through 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 view for conceptually explaining fine particles deposited on the filter medium when a conventional filter device is used, and FIG. 3B is a diagram of the filter medium 22 when the filter device 1 is used. It is a figure which illustrates notionally the fine particles deposited on the.
In the conventional filtration device, the filter medium does not rotate, and as shown in FIG. 3A, fine particles are likely to be deposited near the upstream surface of the filter medium. For this reason, surface filtration easily occurs, and the pressure loss increases in a short time. Therefore, it is necessary to replace the filter medium even if many areas (uncollected areas) where fine particles can be collected remain near the downstream surface of the filter medium. In FIG. 3, the fine particles collected in the filter medium are conceptually represented by a number of circles.
On the other hand, in the filtration device 1 of the present embodiment, the fine particles collected on the filter medium 22 are subjected to 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. As shown, it is deposited on the outer periphery of the filter medium 22. For this reason, 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 the time until the final pressure loss is reached is extended. Since fine particles can be deposited from the outer periphery of the filter medium 22 and retained in a wider area in the filter medium 22, there are few uncollected areas remaining in the filter medium 22 until the final pressure loss is reached, and the amount of dust retained is This increases the life of the filter medium 22. The dust holding amount 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 rapidly, the movement of the fine particles collected by the filter medium to the outer peripheral side hardly occurs, and the filter device 1 of the present embodiment. Compared to the case where is used, the time to reach the final pressure loss is short. In addition, the amount of fine particles deposited in the filter medium 22 does not increase as much as the filtration device 1 of the present embodiment is used, the effect of increasing the dust retention amount is suppressed, and the life span is small.
In this embodiment, when the filling rate of the filter medium 22 is 0.05 or more, as described above, the collected particles are moved to the outer peripheral side by centrifugal force by appropriately adjusting the rotation speed of the filter medium 22. Easy to move. For this reason, it takes a long time to reach the final pressure loss, and the lifetime is increased by increasing the amount of dust. According to the filtration device 1 of this embodiment, when the filtration device 1 is used in an environment where the concentration of fine particles having a small particle diameter such as PM2.5 or PM10 is high, it is possible to suppress an increase in the replacement frequency of the filter medium 22. 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 with high collection efficiency and low pressure loss.

  The rotational speed of the filter medium 22 adjusted according to the above-described range of the filling rate is specifically 1000 revolutions / minute or more, and 1500 revolutions / minute or more in that the effect of greatly extending the life is obtained. Preferably it is 2000 rotations / minute or more. The upper limit value of the rotation speed is not particularly limited, but is, for example, 5000 rotations / minute.

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

  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 illustration of the wall member 30 is omitted.

  The housing | casing 10 has the space 10a which takes in and passes gas. 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 opened. The airflow direction X is a direction in which gas passes through the space 10 a of the housing 10. According to an example, the housing 10 may be a duct installed in a building.

  The outer frame 24 is disposed in the space 10 a with a gap between the outer frame 24 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 includes a guide portion 25, an annular wall portion 26, and a support portion 27, which are integrally formed.

  The guide part 25 is a part surrounding the outer peripheral part of the filter medium 22 from the outer peripheral side. In the example shown in FIG. 2, the guide portion 25 has a cylindrical shape extending in a direction parallel to the airflow direction X and extending in the circumferential direction. The filter medium 22 is disposed on the inner peripheral side of the guide portion 25 in a radially compressed state, or the outer peripheral portion is bonded to the inner wall of the guide portion 25, and there is no gap with respect to the guide portion 25. It touches. The guide portion 25 has a function of preventing the air that has entered the filter medium 22 and has flowed through the filter medium 22 to the outer peripheral side from flowing into the gap G and guides it downstream in the airflow direction X. The guide part 25 is separated from the housing 10 with a gap.

  It is preferable that the guide part 25 does not have a through-hole. Thereby, it is possible to prevent the fine particles collected by the filter medium 22 from passing through the through hole and flowing out into the gap between the guide portion 25 and the inner wall of the housing 10 and contaminating the downstream side. However, according to an example, the guide part 25 may have a through hole. The guide part 25 may have, for example, a mesh 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 on the filter medium 22 can be taken out to the outer peripheral side of the filter body 20 through the guide portion 25. Thereby, the filter medium 22 can be used longer. In this case, for example, on the downstream side of the guide portion 25 in the housing 10, a container or the like for receiving the fine particles discharged from the filter medium 22 is disposed.

  The annular wall portion 26 is a portion extending toward the rotation center line Z so as to contact 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 center portion of the outer frame 24 through which the rotation center line Z passes and the annular wall portion 26 so as to contact the filter medium 22 from the downstream side. The support portion 27 is preferably provided in a plurality of two, three, or four or more, and is preferably arranged to extend radially from the central portion of the outer frame 24 as illustrated. The support portion 27, together with the annular wall portion 26, prevents the filter medium 22 from falling out from the outer frame 24 to the downstream side. Moreover, the flow volume of the air which passes the filter medium 22 is ensured because the several support part 27 is arrange | positioned at intervals in the circumferential direction.

  The outer frame 24 and the filter medium 22 constitute the filter body 20. According to an example, the filter body 20 may not include the outer frame 24 described above. In this case, the filter medium 22 is passed through a rotation shaft 42 described later and fixed so as to rotate integrally with the rotation shaft 42.

  According to an example, the filter body 20 may have a plurality of filter media 22. For example, the plurality of filter media 22 are stacked 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 gaps.

  The wall member 30 is a member that forms a passage 30 a that restricts the flow rate of the gas taken into the housing 10. In the example illustrated 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 disposed in the housing 10. The wall member 30 is welded to the housing 10 or connected via a seal 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 that extends from the upstream end of the housing 10 to the inner peripheral side and extends 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 defining the passage 30a so as to block the air flow to the opposite side (upstream side) of the airflow direction X. Yes. In the example shown in FIG. 2, the passage 30 a 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 10 a 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 accumulate from the outer peripheral portion of the filter medium 22. For this reason, the effect | action which suppresses generation | occurrence | production of surface filtration and becomes difficult to clog by improving the airflow which passes the filter medium 22 to the center part of the filter medium 22 improves. In the above conventional filtration device in which the filter medium does not rotate, fine particles accumulate from the upstream portion in the thickness direction of the filter medium. Therefore, surface filtration occurs and the air flow is likely to be hindered and clogged easily. The wall surface 32a is a smooth surface having no dents or through holes. The wall surface 32a extends in a direction crossing the airflow direction X, and extends in a direction orthogonal to the airflow direction X in the illustrated example. The wall surface 32a is preferably disposed close to the filter medium 22 so that the air that has passed through the passage 30a enters the center 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 30 mm or less, for example.

  The length in the radial direction of the first wall portion 32 (one side 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 center of the filter medium 22 without excessively reducing the air flow rate. A length of ˜25% is preferred.

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

In addition, according to an example, the first wall portion 32 has a truncated cone shape that is inclined and extended with respect to the airflow direction X so as to continuously widen the passage 30a from the end on the inner peripheral side toward the upstream side. There may be.
FIG. 4 is a diagram illustrating a filtration device 1 according to another example of the present embodiment.
In the example shown in FIG. 4, a screw thread 34 a extending in a spiral shape is provided on the inner wall of the second wall portion 34. In the filtration device 1 of the present embodiment, since the flow rate is restricted by the passage 30a, the air flow rate is likely to decrease compared to the case where the wall member 30 is not provided. However, in the filtration device 1 including the wall member 30 having the form shown in FIG. 4, the air is supplied so as to flow in the direction indicated by the arrow along the thread 34 a, while the center portion of the passage 30 a is disposed in the housing. By ensuring the flow of the air flow returning from the inside to the upstream side, the degree of decrease in the ventilation rate can be suppressed.

  The fan 50 takes in air containing fine particles and generates an airflow that passes through the inside of the housing 10. In the illustrated example, the fan 50 is coupled to the rotation shaft 42 and is driven to rotate by the driving device 40. In the illustrated example, since the filter body 20 and the fan 50 are integrally rotated by the drive device 40, the power consumption is suppressed compared to the case where the filter body 20 and the fan 50 are rotationally driven by different drive devices. Can do.

  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 by the filter medium 22 are adjusted in the filter medium 22 by appropriately adjusting the rotational speed of the filter medium 22. It becomes easy to move with. For this reason, it takes a long time to reach the final pressure loss, and the lifetime is increased by increasing the amount of dust.

The filtration device 1 of the present embodiment can be suitably used as a dust collector or the like that takes in and cleans air in which dust is floating in a place where dust is easily generated indoors or outdoors. For example, in a work site where oil mist is likely to occur, a work site where cutting is performed, or a room equipped with a cooking facility or the like, the 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 apparatus 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 filter device 1, and is taken into the housing 10 together with the oil mist. The oil collected in the filter 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 welding, cutting, or the like, in which metal powder such as fume and other powders are easily generated.

  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 a vertical direction provided in a building in contact with the ceiling can be used as the casing.

(Experimental example)
In order to confirm the effect of the present invention, in the filtration device of the above embodiment, the amount of dust retention was measured by varying the number of rotations.
The filter medium used was a laminate of three nonwoven fabrics made of organic fibers (PET fiber nonwoven fabric DS600 manufactured by Nippon Mining Co., Ltd.). This filter medium had a basis weight of 0.013 g / cm ² , a fiber density of 1.38 g / cm ³ , a thickness of 20 cm, and a filter medium filling ratio of 0.047%.
The test method was performed according to JIS B 9908: 2011. The process was terminated when the final pressure loss reached 498 Pa, and the amount of dust retained per air filter (g / unit) was calculated. The amount of dust was calculated by measuring the mass of the filter medium before and after the test and calculating the difference.
Further, as a collection efficiency, mass method particle collection rate (%) was determined in accordance with JIS B9908 Format 3.
The results are shown in Table 1.

  From comparison between Experimental Example 1 and Experimental Examples 2 and 3, it was confirmed that the amount of dust retention was increased by adjusting the rotational speed when the filling rate of the filter medium was less than 0.05. When the filling rate of the filter medium is less than 0.05, the rotation speed is adjusted so that the fine particles collected on 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 thought that the amount of dust was increased.

From Experimental Examples 1 to 3, it was confirmed that the amount of dust retention was changed by adjusting the rotation speed when the filling rate of the filter medium was less than 0.05.
Moreover, it was confirmed from the comparison of Experimental Examples 1-3 that collection efficiency rises with the increase in rotation speed.

  As mentioned above, although the filtration apparatus of this invention was demonstrated in detail, the filtration apparatus of this invention is not limited to the said embodiment, In the range which does not deviate from the main point of this invention, you may make various improvement and a change. Of course.

DESCRIPTION OF SYMBOLS 1 Filtration apparatus 12 Support body 10 Housing | casing 10a Space 20 Filter body 22 Filter medium 24 Outer frame 25 Guide part 26 Annular wall part 27 Support part 30 Wall member 30a Channel 32 First wall part 32a Wall surface 34 Second wall surface 34a Thread 40 Drive Device 42 Rotating shaft 44 Motor 50 Fan

Claims (5)

A filter medium for collecting fine particles in the gas;
A drive device for rotating the filter medium,
The filling rate of the filter medium is less than 0.05,
The drive device rotates the filter medium at a rotation speed adjusted according to the range of the packing rate so that the fine particles collected by the filter medium move in a direction away from the rotation center of the filter medium. A filtration device.   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 airflow is 0.1 or more.   The filtration device according to claim 1 or 2, wherein an average fiber diameter of the filter medium is more than 10 µm and not more than 100 µm.   The filtration device according to any one of claims 1 to 3, wherein the filling rate is constant from a position of the filter medium passing through the rotation center to a position of an end portion of the filter medium away from the rotation center.   Furthermore, the filtration apparatus of any one of Claim 1 to 4 provided with the outer frame which surrounds the said filter medium from the outer peripheral side.

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