JP7629170B2 - Filter winding device and filter media roll - Google Patents

Description

The present invention relates to a filter winding device and a filter media roll for dust collection.

An example of a filter device equipped with a filter that purifies gas is shown in Patent Document 1. In the filter device of Patent Document 1, the filter is wound in a roll to reduce the number of times the filter needs to be replaced, and the filter is wound up at a predetermined interval.

JP 2008-44482 A

In the filter device of Patent Document 1, the filter is rolled up so that the contaminated surface that has adsorbed dust and other particles from the gas is on the outside, so when workers handle the roller that has the used filter rolled up, there is a risk that the workers will come into direct contact with contaminants.
From this perspective, an object of the present invention is to provide a filter device and a filter medium roll that are capable of appropriately taking measures against contamination during maintenance.

In order to solve such problems, the present invention provides a filter device including a gas inlet section for taking in a gas to be purified, dust collecting means for removing dust from the gas flowing in from the gas inlet section, and a gas outlet section for discharging the purified gas from which the dust has been removed. The dust collecting means includes a delivery section for rotatably holding a filter roll in which a filter material is wound in a roll shape, a winding section for winding up the filter material delivered from the delivery section, and a dust collecting section in which the filter material stretched between the delivery section and the winding section is disposed. The gas flowing in from the gas inlet section passes through the filter material in the dust collecting section, and the winding section has a drive rotating shaft that winds up the filter material so that the dust collecting surface of the filter material facing the upstream side of the gas flow is on the inside , the filter material roll has a delivery side core material around which the filter material is wound, and a covering film that covers the outer periphery of the winding roll wound up in the winding section is connected to the rear end of the filter material in the winding direction, and the rear end of the covering film in the winding direction is connected to the delivery side core material via a retaining string .
According to the filter device of the present invention, the filter medium is wound up so that the dust collecting surface faces inward, so that when an operator handles the wound roll, the operator is unlikely to directly touch the dust adhering to the dust collecting surface. By using such a filter device, it is possible to preferably take measures against contamination during maintenance. Furthermore, since the outer peripheral surface of the winding roll is covered with a covering film, the operator is even less likely to touch the dust on the dust collecting surface when removing the winding roll.

In the filter device of the present invention, it is preferable that the dust collection means is provided in a plurality of spaces spaced apart in the direction of gas flow. With this configuration, the gas passes through the filter media multiple times, improving the cleaning efficiency. Furthermore, by changing the mesh size of the filter media of each dust collection means, dust collection can be performed in a step-by-step manner and efficiently.

In the filter device of the present invention, it is preferable that an adhesive is provided at least on the rear end of the covering film in the winding direction. With this configuration, the covering film is fixed with adhesive on the outer peripheral surface where the filter material and covering film are wound up, so that the winding roll is integrated and the winding roll can be easily handled.

In the filter device of the present invention, it is preferable that in the winding section, a core around which the filter medium is wound is detachably provided on the drive shaft, and the winding roll in which the core, filter medium, and covering film are integrally fixed with the adhesive can be removed from the drive shaft and discharged as is. With this configuration, the winding roll can be removed and discharged as is, reducing the labor and time required for replacing and disposing of the filter medium.

In the filter device of the present invention, it is preferable that a barometer is installed on both the upstream and downstream sides of the filter medium. When dust clogs the dust collection surface of the filter medium, the pressure difference between the upstream and downstream sides of the filter medium increases. Therefore, by installing a barometer on both the upstream and downstream sides of the filter medium, the degree of clogging of the filter medium can be grasped, and the timing of feeding and winding the filter medium can be optimized.

In the filter device of the present invention, it is preferable that the winding section winds up the filter material at a constant length every predetermined time. With this configuration, the flow rate of the gas passing through the dust collecting section can be stabilized.

In the filter device of the present invention, it is preferable that at least one of the plurality of dust collecting means is a spare dust collecting means that is used when the other dust collecting means are not in use. With such a configuration, it is possible to continue purifying the gas even during maintenance of one dust collecting means.
In the filter device of the present invention, it is preferable that a guide string is attached to a front end portion in the winding direction of the filter material so as to be engaged with the winding-side core material.
In the filter device of the present invention, it is preferable that a first guide rod extending in the width direction of the covering film is fixed to the rear end of the covering film in the winding direction, and a second guide rod extending in the width direction of the filter material is fixed to the front end of the filter material in the winding direction.
In the filter device of the present invention, it is preferable that the front end portion of the filter material in the winding direction has corners at both ends of the filter material in the width direction chamfered to form inclined surfaces, and is formed so as to narrow toward the front end portion.
The filter device of the present invention is preferably used for removing dust containing radioactive materials from a gas.

The second invention for solving the above problem is a filter material roll comprising a core material, a covering film wrapped around the core material, and a filter material connected to the covering film , wherein the core material and the covering film are connected via a retaining string, and a retaining string is attached to the front end of the filter material in the winding direction, which is connected to a winding section that winds up the filter material .
According to the filter medium roll of the present invention, the filter medium roll can be easily installed by inserting the core material into the rotating shaft of the delivery section. In addition, after the filter medium is wound up in the winding section with the dust-collecting surface facing inward, the outer circumferential surface of the winding roll can be covered with a covering film, so that workers are less likely to come into contact with the dust on the dust-collecting surface. Therefore, when replacing a used filter medium roll, contamination countermeasures can be suitably performed.

The filter device and filter media roll of the present invention make it difficult for workers to directly touch the dust adhering to the dust collection surface of the filter media when replacing the winding roll, making it possible to carry out anti-contamination measures in an ideal manner.

1 is a schematic configuration diagram showing a filter device according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state where winding of a filter medium of a filter device according to an embodiment of the present invention is started. FIG. 2 is a perspective view showing a state in which winding of a filter medium in a filter device according to an embodiment of the present invention has been completed. 1 is a perspective view showing a winding roll formed with a filter device according to an embodiment of the present invention.

A filter device and a filter media roll according to an embodiment of the present invention will be described with reference to the attached drawings. First, the configuration of the filter device will be described. FIG. 1 is a schematic diagram showing a filter device according to an embodiment of the present invention. In this embodiment, the case of removing dust containing radioactive materials from gas will be described as an example. In this embodiment, the filter device 1 is used to purify the gas in a work room in a factory or the like where a coating layer containing radioactive materials is peeled off. Dust generated during the peeling work is suspended in the gas (air) in such a work room.

As shown in FIG. 1, the filter device 1 includes a gas inlet 2, a dust collection means 10, and a gas outlet 3. A high-performance dust collector 5 equipped with a HEPA filter 4 is provided downstream of the filter device 1, and secondary decontamination is performed by the high-performance dust collector 5. The filter device 1 performs primary decontamination to remove dust and debris from the gas before secondary decontamination.

The gas inlet section 2 is a section for taking in the gas to be cleaned. The gas inlet section 2 sends gas A from within a work room of a factory using a pump (not shown).
The dust collecting means 10 is provided continuous with the gas inlet portion 2, and removes dust from the gas A that has flowed in from the gas inlet portion 2. The dust collecting means 10 includes a delivery portion 11, a winding portion 31, and a dust collecting portion 51.
The delivery section 11 is a section that rotatably holds the filter media roll 13 formed by winding the filter media 12 into a roll shape. The filter media 12 is formed by forming a porous material such as a nonwoven fabric into a long strip shape. As shown in FIG. 2, the filter media roll 13 includes a core material 14, the filter media 12, and a covering film 15. The delivery section 11 is provided with a rotating shaft 16 that rotatably holds the filter media roll 13. The filter media roll 13 is detachable from the rotating shaft 16. The rotating shaft 16 is made of a metal rod material with a square cross section. The rotating shaft 16 is freely rotatable and rotates together with the filter media roll 13. The delivery section 11 is provided with guide rollers 19, 19 that guide the filter media 12 delivered from the filter media roll 13 to a dust collection position. The filter media 12 passes between the guide rollers 19, 19 and is delivered to the dust collection position of the dust collection section 51.

The core material 14 is a member that becomes the core of the filter media roll 13, and is composed of a square pipe with a square cross section. The length dimension of the core material 14 is approximately equal to the vertical width dimension of the filter media 12. The core material 14 is attached to a rotating shaft 16 and rotates together with the rotating shaft 16. A covering film 15 is wrapped around the outer periphery of the core material 14.
The covering film 15 covers the outer periphery of the filter medium 12 wound in the winding section 31 to separate the filter medium 12 from the outside. The covering film 15 is made of an airtight material and is formed in a band shape with a width dimension equal to the vertical width dimension of the filter medium 12. The covering film 15 has a length sufficient to cover at least one circumference of the wound filter medium 12. The filter medium 12 is connected to the front end of the covering film 15 in the winding direction.

As shown in FIG. 3, a guide rod 17 extending in the vertical direction is fixed to the rear end of the covering film 15 in the winding direction. The guide rod 17 is for reinforcing the rear end of the covering film 15 so that it does not bend, and is made of, for example, a metal bar. The guide rod 17 is fixed by folding the rear end of the covering film 15 so as to wrap around the guide rod 17 and welding it. The rear end of the covering film 15 is connected to the core material 14 via a retaining string 18. The retaining string 18 is for maintaining the tension of the filter material 12 and the covering film 15 between the delivery section 11 and the winding section 31 so that the rear end of the covering film 15 does not fall down after the covering film 15 separates from the core material 14 when the winding of the filter material 12 is completed. The retaining string 18 is wound around the core material 14 in the state of the filter material roll 13, and is sent out from the core material 14 when the winding of the filter material 12 is completed. After being fed out from the core material 14, the retaining string 18 is stretched between the rear end of the covering film 15.

A weakly viscous adhesive is applied to the surface of the covering film 15. This weakly viscous adhesive is a sealant for bonding the covering films 15 together when they are wrapped around the filter medium 12 in the winding section 31, and has a viscosity that allows the covering film 15 to be peeled off when in the filter medium roll 13 state. The weakly viscous adhesive needs to be applied to at least the surface of the rear end of the covering film 15 in the winding direction (the inner end when in the filter medium roll 13 state), and may be applied to the entire surface of the covering film 15.

The filter medium 12 has a length that allows multiple dust collections. The length required for one dust collection is equal to the width of the dust collection section 51 through which the gas to be purified flows. That is, the filter medium 12 has a length that is at least twice the width of the dust collection section 51. By lengthening the filter medium 12, the number of times the filter medium roll 13 is replaced can be reduced. As shown in FIG. 2, the front end of the filter medium 12 in the winding direction has upper and lower corners chamfered to form an inclined surface, and is formed so as to become narrower toward the front end. A guide rod 20 extending vertically is fixed to the front end of the filter medium 12 in the winding direction. The guide rod 20 is for reinforcing the front end of the filter medium 12 so that it does not bend, and is made of, for example, a metal bar. The guide rod 20 has a length obtained by subtracting the height corresponding to the upper and lower chamfered portions from the height of the filter medium 12. The guide rod 20 is fixed by folding the front end of the filter medium 12 so as to wrap around the guide rod 20 and welding it. A guide string 21 is attached to the front end of the filter medium 12. When winding of the filter medium 12 starts, the guide string 21 is engaged with a core material 34 through which a drive rotation shaft 32 of a winding unit 31 (described later) is inserted.
The guide string 21 does not have to be fixed in advance to the front end of the filter medium 12. In this case, it is preferable to form a locking hole in the front end of the filter medium 12 so that the guide string 21 can be locked.

The winding section 31 is a section that winds up the delivered filter medium 12. The winding section 31 is provided with a drive rotating shaft 32 for winding up the filter medium 12 delivered from the filter medium 12. The drive rotating shaft 32 is driven by a drive motor 32a provided in the winding section 31, and is made of a metal bar material with a rectangular cross section. The drive rotating shaft 32 rotates in a direction (counterclockwise in this embodiment) such that the dust collection surface of the filter medium 12 (the surface facing the gas inlet section 2 (the upstream side of the flow of gas A) in the dust collection section 51) faces inward.
The core material 34 is a member that is detachably attached to the drive rotating shaft 32, and is made of a square pipe with a square cross section. The drive rotating shaft 32 is inserted into the core material 34. The core material 34 is provided with a locking portion 35 for locking the guide string 21. When the drive rotating shaft 32 is rotated, the core material 34 rotates together with the drive rotating shaft 32, and the guide string 21 is wound around the core material 34. The filter medium 12 is further pulled and guided to the winding section 31 and wound around the core material 34. In this state, the filter medium 12 is stretched between the delivery section 11 and the winding section 31, and is stretched over the dust collecting section 51.
The winding section 31 is provided with guide rollers 36, 36 that guide the filter medium 12 in the dust collecting section 51 to the outer periphery of the winding roll 33. The filter medium 12 passes between the guide rollers 36, 36 and is guided to the outer periphery of the winding roll 33, the diameter of which gradually increases.

The dust collecting section 51 is a section that removes dust from the gas A that flows in from the gas inlet section 2. In the dust collecting section 51, the filter material 12 is arranged in a straight line (flat shape) between the delivery section 11 and the winding section 31. The gas A flows in a direction perpendicular to the filter material 12 arranged in the dust collecting section 51. Dust particles in the gas A that are larger than the holes in the filter material 12 are captured by the filter material 12, and dust particles smaller than the holes and gas pass through the filter material 12. The upstream surface of the filter material 12 becomes the dust collecting surface that removes dust.
The dust collecting section 51 includes a wire mesh 52. The wire mesh 52 is installed downstream of the filter medium 12. The wire mesh 52 is a pressing member for preventing the filter medium 12 from bending downstream due to the gas flow, and is formed in a flat shape. The wire mesh 52 has mesh sizes that do not obstruct the gas flow.

When dust collection is performed for a certain period of time in the dust collection section 51, the collected dust clogs the meshes of the filter medium 12, causing poor gas flow. At this point, the drive shaft 32 is rotated to wind up the old filter medium 12 (the filter medium 12 exposed to the dust collection section 51) in the winding section 31. As a result, new filter medium 12 is sent out from the delivery section 11, and the filter medium 12 in the dust collection section 51 is automatically renewed.

The dust collection section 51 is divided by the filter material 12. There is a difference in air pressure between the upstream and downstream sides of the filter material 12 (the air pressure in the downstream part is smaller), and when the mesh of the filter material 12 becomes clogged with dust, the difference in air pressure becomes larger. Therefore, in this embodiment, a barometer 55 is installed on each of the upstream and downstream sides of the filter material 12, and the drive rotation shaft 32 is rotated according to the air pressure measured by the barometer 55. Specifically, the air pressure difference between the upstream and downstream sides of the filter material 12, at which the mesh of the filter material 12 is assumed to be clogged, is set in advance, and when the air pressure difference reaches the set value, the drive rotation shaft 32 is rotated. The drive rotation shaft 32 rotates the filter material 12 so as to wind up the length of the dust collection section 51. The rotation of the drive rotation shaft 32 is automatically controlled by a control device (not shown) connected to the drive motor 32a and the barometer 55. The rotation of the drive shaft 32 may be performed manually by an operator who has confirmed that the air pressure difference has reached a set value using a lamp or buzzer.

The winding length of the filter medium 12 per rotation of the drive rotating shaft 32 increases as the outer diameter of the winding roll 33 increases. Therefore, in this embodiment, the number of rotations of the drive rotating shaft 32 per renewal is set in advance according to the renewal number of the filter medium 12 (how many times the winding work has been performed). Specifically, the fewer the renewal number, the smaller the outer diameter of the winding roll 33, so the number of rotations of the drive rotating shaft 32 required to wind the renewal length of the filter medium 12 (the length of the dust collecting section 51) increases. Therefore, the number of rotations of the drive rotating shaft 32 corresponding to the renewal number is calculated and input to the control device, and the drive rotating shaft 32 is rotated at the set number of rotations according to how many times the renewal has been performed.
The number of rotations of the drive rotating shaft 32 per update is not limited to being set according to the number of updates, and may be set according to the outer circumferential diameter of the winding roll 33. The outer circumferential diameter of the winding roll 33 may be directly measured by a sensor, or may be calculated according to the cumulative number of rotations of the drive rotating shaft 32.

After the filter medium 12 is renewed multiple times, the filter medium 12 is wound around the core material 34 in the winding section 31 to form the winding roll 33. The winding roll 33 is formed by winding the guide string 21 and the filter medium 12 around the core material 34 from the inside, and finally, the covering film 15 is wound around the outer periphery of the filter medium 12. Since a weak adhesive is applied to the surface of the covering film 15, the covering film 15 is automatically fixed in place when it is wound. It is preferable to wrap the holding string 18 around the outside of the covering film 15 and tie it down.

In the winding section 31, the core material 34 is removably attached to the drive shaft 32, so the winding roll 33 can be easily removed while still being fixed with the covering film 15. The removed winding roll 33 is inserted into a disposal bag or the like and disposed of.

1, in this embodiment, a dust collecting means 10 including a delivery section 11, a dust collecting section 51, and a winding section 31 is provided in a plurality of stages (five stages in this embodiment) at intervals in the flow direction of the gas A. That is, a plurality of rows of dust collecting sections 51 (filter media 12) are arranged between the gas inlet section 2 and the gas outlet section 3. The plurality of rows of filter media 12, 12... are arranged at intervals in the flow direction of the gas A, so that the gas A flowing in from the gas inlet section 2 passes through the plurality of rows of filter media 12, 12... in sequence.
The five-stage stack of filter media 12, 12... are configured so that the mesh size decreases from the upstream side to the downstream side. With this configuration, larger dust particles can be removed with the upstream filter media 12, and smaller dust particles can be removed stepwise and efficiently toward the downstream side.

Although a barometer 55 is provided on the upstream and downstream sides of the filter media 12, the barometer 55 is shared between adjacent filter media 12, 12. In other words, one barometer 55 is provided between the upper filter media 12 and the downstream filter media 12 as a barometer on the downstream side of the upper filter media 12 and a barometer on the upstream side of the downstream filter media 12. The control device estimates the dust collection state of each filter media 12 by calculating the differential pressure between the adjacent barometers 55, 55, and when the differential pressure reaches a set value, the drive rotation shaft 32 of the corresponding winding section 31 is rotated to renew the filter media 12.

According to the filter device 1 of this embodiment, the filter medium 12 is wound up so that the dust collecting surface faces inward, so that when an operator handles the winding roll 33, the operator is unlikely to directly touch the removed dust. Therefore, with this filter device, it is possible to preferably take measures against contamination during maintenance. In addition, since the outer peripheral surface of the winding roll 33 is covered with the covering film 15, the filter medium 12 is covered, so that when an operator removes the winding roll 33, the operator is even less likely to touch the dust on the dust collecting surface.
In addition, in the filter device 1 of this embodiment, the covering film 15 is fixed to the outer circumferential surface of the winding roll 33 with an adhesive provided on the covering film 15, so the winding roll 33 is integrated, making it easier to handle. Furthermore, the winding roll 33 is integrated at the same time as the winding of the filter medium 12 is completed, so the labor required for fixing can be reduced. Note that the winding roll 33 can be firmly fixed by wrapping and tying the outside of the covering film 15 with the holding string 18.

In the winding section 31, the core material 34 is removably attached to the drive shaft 32, so the winding roll 33 can be easily removed. In addition, the winding roll 33 can be removed and discharged as is, reducing the labor and time required to replace and dispose of the filter material.

The dust collecting means 10 is provided in multiple stages, and the gas A flowing in from the gas inlet 2 passes through multiple rows of filter media 12, 12..., improving the cleaning efficiency. Furthermore, by gradually making the mesh size of the filter media 12 of each dust collecting means 10 finer toward the downstream side, efficient dust collection can be performed in stages.
In addition, in this embodiment, a barometer 55 is installed in each of the dust collection sections 51, 51 upstream and downstream of the filter material 12, and the occurrence of an air pressure difference is detected from the barometer measurement value, so that the filter material 12 in the dust collection section 51 that is clogged with dust can be replaced with new filter material 12 at an appropriate time.

According to the filter media roll 13 of this embodiment, the filter media roll 13 can be easily installed simply by attaching the core material 14 to the rotating shaft 16 of the delivery section 11. In addition, after the filter media 12 is wound up in the winding section 31 with the dust collecting surface facing inward, the outer peripheral surface of the winding roll 33 is covered with a covering film 15, so that the removed dust is on the inside of the winding roll 33 and is not exposed to the outside. This makes it difficult for workers to directly touch the removed dust. Therefore, even with this filter media roll 13, contamination countermeasures during maintenance can be carried out appropriately.

Next, a filter device according to a modified embodiment of the present invention will be described. In the above embodiment, the gas A is purified by simultaneously using five stages of dust collection means 10, but a part (at least one) of the dust collection means 10 may be used as a spare (backup) dust collection means to be used when the remaining dust collection means 10 are not in use. That is, before starting the final winding operation of the filter medium 12 of the dust collection means 10 in use, the filter medium roll 13 of the spare dust collection means 10 is sent to the dust collection section 51, and then the final winding of the filter medium 12 is performed in the dust collection means 10 in use. The dust collection means 10 in which the filter medium roll 13 has been replaced becomes the spare dust collection means. In this way, it is possible to continue purifying the gas A even during maintenance of the dust collection means 10 in use (when replacing the filter medium roll 13).

Although the embodiment for carrying out the present invention has been described above, the present invention is not limited to the above embodiment, and appropriate design changes are possible within the scope of the present invention. For example, in the above embodiment, the differential pressure between the upstream side and the downstream side of the filter medium 12 is calculated to rotate the drive rotating shaft 32 of the winding section 31, but the present invention is not limited to this. For example, the drive rotating shaft 32 may be rotated at a predetermined number of rotations every predetermined time. Specifically, the time for which the filter medium 12 becomes clogged with dust is preset and input into the control device, and when the set time has elapsed from the time when dust collection was started, the drive rotating shaft 32 is rotated to replace the filter medium 12. With this configuration, the filter medium can be replaced periodically with a simple configuration without providing a barometer.

In the above embodiment, a wire mesh 52 is provided downstream of the filter medium 12 in the dust collection section 51 to prevent the filter medium 12 from bending downstream, but this is not limited to the above. For example, the rotating shaft 16 of the delivery section 11 may be configured to require a certain torque to rotate, and the filter medium 12 may be stretched with tension between the drive rotating shaft 32 and the rotating shaft 16.

REFERENCE SIGNS LIST 1 filter device 2 gas inlet section 3 gas outlet section 10 dust collecting means 11 delivery section 12 filter medium 13 filter medium roll 14 core material 15 covering film 16 rotating shaft 31 winding section 32 drive rotating shaft 33 winding roll 34 core material 35 engaging section 51 dust collecting section 52 wire mesh 55 barometer

Claims (12)

A filter device comprising a gas inlet portion for taking in a gas to be purified, a dust collecting means for removing dust from the gas flowing in from the gas inlet portion, and a gas outlet portion for discharging the purified gas from which the dust has been removed,
The dust collecting means includes a delivery section that rotatably holds a filter roll in which a filter material is wound in a roll shape, a winding section that winds up the filter material delivered from the delivery section, and a dust collecting section in which the filter material is disposed, the filter material being stretched between the delivery section and the winding section;
The gas flowing in from the gas inlet portion passes through the filter material of the dust collecting portion,
The winding unit includes a drive shaft that winds up the filter material so that a dust collection surface of the filter material facing the upstream side of the gas flow is on the inside,
The filter medium roll includes a delivery-side core material around which the filter medium is wound,
A covering film is provided at the rear end of the filter material in the winding direction to cover the outer periphery of the winding roll wound in the winding section,
The rear end of the covering film in the winding direction is connected to the delivery-side core material via a retaining string.
A filter device comprising: The filter device according to claim 1 , wherein the dust collecting means is provided in a plurality of portions spaced apart from each other in the gas flow direction. The filter device according to claim 1 , wherein an adhesive is provided at least on a rear end portion of the cover film in the winding direction. In the winding section, a winding core around which the filter medium is wound is detachably provided on the drive rotary shaft,
The filter device according to claim 3, characterized in that the winding roll in which the winding-side core material, the filter material, and the covering film are integrally fixed with the adhesive can be removed from the drive shaft and discharged as is. The filter device according to claim 2 , further comprising a pressure gauge disposed on each of the upstream and downstream sides of the filter medium. The filter device according to any one of claims 1 to 4 , wherein the winding section winds up the filter medium at a constant length at predetermined time intervals. 5. The filter device according to claim 1 , wherein at least one of the plurality of dust collecting means is a spare dust collecting means that is used when the other dust collecting means are not in use. A guide string is attached to the front end of the filter material in the winding direction to be engaged with the winding-side core material.
5. The filter device according to claim 4. A first guide rod is fixed to a rear end of the cover film in the winding direction, the first guide rod extending in a width direction of the cover film,
A second guide rod extending in the width direction of the filter material is fixed to the front end portion of the filter material in the winding direction.
2. The filter device according to claim 1 . The front end of the filter material in the winding direction is formed such that the corners at both ends of the filter material in the width direction are chamfered to form inclined surfaces, and the filter material is formed so as to become narrower toward the front end.
2. The filter device according to claim 1 . Used to remove radioactive dust from gases
2. The filter device according to claim 1 . The filter includes a core material, a covering film wound around the core material, and a filter medium connected to the covering film.
The core material and the covering film are connected via a retaining string,
A retaining string is attached to the front end of the filter material in the winding direction, and is connected to a winding section that winds up the filter material.
A filter media roll characterized by:

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