Fine particle collection device

Abstract

To provide a fine particle collection device where collection efficiency is increased by preventing the short circuit of a polluted air stream by the rotation of a filter with a simple structure, and maintainability is excellent.SOLUTION: A fine particle collection device comprises one or more filters to collect fine particles contained in a polluted air stream and a filter retainer being a rotor to hold the filter. The filter retainer has a filter holding part, a rotation support part connected to the driving shaft of a motor and a projection part installed at the outer peripheral side of the filter retainer and rotatably housed in a retainer storage chamber. The retainer storage chamber has a first partition plate having an opening at an upstream side and a second partition plate having an opening at a downstream side. In operation, the first partition plate and the filter retainer being the rotor are functioned as a seal when the filter retainer is rotated by the motor.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a particle collecting device that collects particles such as oil mist, oily smoke, and fumes contained in the air and discharges clean air. [Background technology]

[0002] Patent Document 1 discloses a mist collection device that is equipped with a rotating disk with air vents in the collection section to collect oil mist and the like generated when machining metals and the like with a machine tool, and causes the dust-laden airflow flowing in parallel to the rotation axis to inertially collide with the rotating disk. The centrifugal force of the rotating disk rotating at high speed causes the oil mist to fly out from the outer periphery of the rotating disk, which is perpendicular to the rotation axis, and is collected.

[0003] Patent Document 2 discloses a filtration device that uses the principle of rotating the filter layer to move the captured fine particles in a direction intersecting the gas passage direction, thereby increasing the opportunities for the fine particles to come into contact with the fibers of the filter layer, thereby improving the collection efficiency of the filtration device even with filter media that has low collection efficiency, while suppressing the generation of undesirable air currents that occur as the filter layer rotates.

[0004] Patent Document 3 discloses a method and device for treating oil mist in which an airflow containing oil mist and the like is passed through a rotary filter, so that the liquid in the airflow is collected around the rotary filter by the centrifugal force of the rotary filter, allowing it to be efficiently removed and recovered.

[0005] Non-Patent Document 1 relates to an aerosol particle collection device using a rotary filter, which rotates a filter that is a fiber-packed layer, and collects droplets accumulated in the fiber layer after moving them in the centrifugal direction and re-scattering them by centrifugal force. It discloses that, for a fiber diameter of 10 μm, increasing the rotation speed of the filter significantly improves the collection efficiency for particles with a diameter of 0.5 μm or more, and that when the rotation speed is 3000 rpm, about 80% of particles with a diameter of 1.0 μm can be collected.

[0006] [Patent Document 1] JP 2014-33974 A [Patent Document 2] JP 2018-171559 A [Patent Document 3] Japanese Patent Application Publication No. 8-243331

[0007] [Non-Patent Document 1] Hidesuke Nakajima, Collection of aerosol particles by a rotating filter, Kanazawa University, 2017, Doctoral thesis.

[0008] In Patent Document 1, there is a risk that the dust-containing airflow before the oil mist is collected may be short-circuited to the secondary side, which is a clean space.

[0009] In Patent Document 2, in order to prevent the airflow containing dust from short-circuiting to the secondary side without passing through the filter, it is necessary to minimize the gap between the rotating filter body and the inner wall of the casing or to provide a seal.

[0010] In Patent Document 3, a labyrinth seal is provided to prevent the airflow containing droplets from short-circuiting to the secondary side without passing through the filter, but the structure is complex and maintenance is time-consuming.

[0011] In Non-Patent Document 1, the device is merely for experimental use, and there is a possibility that the aerosol particles introduced may pass between the filter medium and the wall (short circuit), preventing the aerosol particles from passing through the filter, and no consideration is given to a method for replacing the filter, making it unsuitable for practical use. Summary of the Invention [Problem to be solved by the invention]

[0012] In consideration of the problems described above, the present invention has an object to provide a particulate matter collection device that rotates a filter, has a simple structure, prevents short-circuiting of the contaminated airflow, improves collection efficiency, and is easy to maintain. [Means for solving the problem]

[0013] The particulate matter collection device of the present invention comprises one or more filters for collecting particulate matter contained in a polluted airflow, and a filter retainer which is a rotating body that holds the filter, the filter retainer having a filter holding portion that holds the filter, a rotation support portion that is connected to the drive shaft of a motor, and one or more protrusions provided on the outer periphery of the filter retainer, and is rotatably housed in a retainer accommodating chamber, the retainer accommodating chamber having a first partition plate on the upstream side having an opening, and a second partition plate on the downstream side having an opening, and when the polluted airflow is caused to flow into the retainer accommodating chamber through the opening of the first partition plate and the clean airflow is caused to flow out from the opening of the second partition plate, when the filter retainer is rotated by the motor, the first partition plate and the filter retainer which is a rotating body function as a seal.

[0014] The fine particles contained in the contaminated airflow passing through the rotating filter are captured by inertial collision and are also affected by centrifugal force and thrown radially out of the filter retainer. Furthermore, by providing protrusions on the outer periphery of the filter retainer housed in the retainer housing, the protrusions function like a fan impeller, generating a rotating airflow in the retainer housing and pushing the air out in the centrifugal direction, thereby increasing the pressure in the retainer housing. The fine particles are separated from the airflow in the retainer housing, and are reliably captured without short circuits or leaks due to the sealing action. There is almost no increase in pressure loss of the filter, and it is possible to extend its life.

[0015] In addition, the filter of the fine particle collection device of the present invention is a regenerative filter, and the filter holding portion has an upstream circular member and a downstream circular member, the filter is sandwiched between the upstream circular member and the downstream circular member, and a gap is provided between the upstream circular member and the first partition plate, so that it functions as a non-contact seal when the filter retainer is rotated.

[0016] The non-contact seal reduces the load on the motor and minimizes the increase in motor power, leading to energy savings. In addition, the regenerative filter can be washed, which reduces waste, unlike disposable filters.

[0017] In addition, the rotating short tube protruding upstream from the opening of the upstream circular member and the fixed short tube protruding downstream from the opening of the first partition plate are arranged concentrically, and the tip of the rotating short tube and the tip of the fixed short tube are arranged to overlap in the axial direction to form a contaminated air flow introduction section, and a gap is provided between the tip of the fixed short tube and the tip of the rotating short tube to function as a non-contact seal when the filter retainer rotates.

[0018] Alternatively, a rotating short tube protruding upstream from the opening of the upstream circular member and a fixed short tube protruding downstream from the opening of the first partition plate are arranged concentrically, the tip of the rotating short tube and the tip of the fixed short tube are arranged so as to overlap in the axial direction, and further, a circular member for non-contact sealing is arranged horizontally concentrically on the upstream circular member at the tip of the rotating short tube or the fixed short tube to form a contaminated air flow introduction section, and a gap is provided between the opening of the circular member for non-contact sealing and the fixed short tube or the rotating short tube, so that it functions as a non-contact seal when the filter retainer rotates.

[0019] By overlapping the tips of the fixed short tube and the rotating short tube, it is possible to accommodate cases where the axial thickness of the filter changes.

[0020] The downstream circular member is further characterized in that a replacement bridge or a support member disc portion of the downstream circular member is provided on the downstream circular member, and a rotating shaft fixing portion, which is a rotating support portion to which a first rotating shaft connected to the drive shaft of the motor is fixed, is provided on the support member disc portion of the replacement bridge or the downstream circular member.

[0021] By connecting the rotation support portion of the filter retainer to the drive shaft of a motor, the rotation of the filter retainer can be freely controlled.

[0022] Furthermore, a filter replacement chamber is provided downstream within the retainer accommodating chamber via a second partition plate, a maintenance door is provided on the side of the filter replacement chamber, and a plurality of filter holding rods are provided between the upstream circular member and the downstream circular member parallel to the rotation shaft of the motor, the filters have a circular plate shape, and at least one of the filters has a through hole with a notch or cutout on its outer periphery for positioning it on the filter holding rod, and the filter holding rod also serves as a protrusion.

[0023] Since the filter can be removed from the filter holding portion without disassembling the filter retainer, maintenance (cleaning) of the regenerative filter can be easily performed.

[0024] Furthermore, a protruding portion such as a protruding rod, a protruding plate, or a protruding blade may be provided on either the outer periphery of the filter holding rod or the outer periphery of the rotating short tube. This can further increase the pressure inside the retainer housing chamber. Furthermore, the position and shape of the protruding portion can be flexible depending on the shape of the filter and the presence of an airflow introduction portion.

[0025] Furthermore, a maintenance door may be provided on the side of the retainer housing chamber, the filter holding section may have a central axis coaxial with the drive shaft of the motor, and one or more regenerative filters may be wound around this central axis. Because the filter can be attached and detached from the central axis through the maintenance door provided in the retainer housing chamber, a filter replacement chamber is not required, resulting in a more compact particulate interception device. [Brief description of the drawings]

[0026] [Figure 1] 1 is a cross-sectional view showing a particulate collection device of the present invention. [Diagram 2] FIG. 1A is a plan view of the filter, and FIG. 1B is an enlarged view of part A in FIG. [Diagram 3] 1A is a perspective view of the filter retainer as viewed from the downstream side, FIG. 1B is a perspective view of the filter retainer as viewed from the upstream side, FIG. 1C is a bottom view of the upstream circular member, and FIG. [Figure 4]1A is an enlarged cross-sectional view of a retainer housing chamber, FIG. 1B is an enlarged view of part A in FIG. 1A, and FIG. 1C is an enlarged view of part B in FIG. [Diagram 5] 11A is a schematic cross-sectional view of a retainer housing chamber of a particulate collection device according to a second embodiment of the present invention, FIG. 11B is a plan view of a filter and a protrusion, and FIG. [Figure 6] 13 is a schematic cross-sectional view of a retainer housing of a particulate collection device according to a third embodiment of the present invention. FIG. [Figure 7] 13A is a schematic cross-sectional view of a retainer housing chamber of a particulate collection device according to a fourth embodiment of the present invention, and FIG. 13B is a plan view of a protrusion. [Figure 8] 13 is a schematic cross-sectional view of a retainer housing of a particulate collection device according to a fifth embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding parts are given the same reference numerals. The side where the polluted airflow flows into the particle collector is called the upstream side, and the side where the clean airflow is discharged is called the downstream side. In addition, the side refers to the surface that is neither upstream nor downstream of the airflow.

[0028] Reference numeral 1 in Fig. 1 denotes a particulate matter collecting device according to a first embodiment of the present invention. A casing 2 is partitioned into a contaminated airflow introduction chamber 3 into which a contaminated airflow containing particulate matter such as oil mist is introduced, a retainer housing chamber 4 for collecting particulate matter contained in the contaminated airflow and turning it into a clean airflow, a filter replacement chamber 5, and a fan chamber 6. The fan chamber 6 is provided downstream of the retainer housing chamber 4 and the filter replacement chamber 5. The contaminated airflow introduction chamber 3, the retainer housing chamber 4, the filter replacement chamber 5, and the fan chamber 6 may each be an independent unit or may be provided in an integrated casing, and each chamber is partitioned by a first partition plate 7, a second partition plate 8, and a third partition plate 9. The airflow passes through openings 7a, 8a, and 9a provided in the first partition plate 7, the second partition plate 8, and the third partition plate 9, respectively.

[0029] An introduction section 10 is provided in the contaminated airflow introduction chamber 3 and is connected to a duct. Directly downstream of the introduction section 10, a punched metal or wire mesh 11 is provided to collect large chips and the like contained in the contaminated airflow.

[0030] A maintenance door 12 is provided on the side of the retainer housing chamber 4 and the filter replacement chamber 5. Here, the maintenance door 12 is provided in a manner that traverses the retainer housing chamber 4 and the filter replacement chamber 5, but a maintenance door can also be provided on the side of each of the retainer housing chamber 4 and the filter replacement chamber 5. A filter 13 and a filter retainer 20 that holds the filter 13 are housed in the retainer housing chamber 4, and the filter 13 can be removed from the filter replacement chamber 5 by opening the maintenance door 12. The filter retainer 20 is housed rotatably within the retainer housing chamber 4. The airflow that has passed through the filter 13 passes through an opening 8a provided in the second partition plate 8.

[0031] The fan chamber 6 is provided with a fan F and a motor M. The fan F is fixed to and rotates on a rotary shaft M2 connected to a drive shaft M1 of the motor M. An exhaust port 16 for discharging a clean air flow is provided downstream of the fan F.

[0032] As shown in Fig. 1, the filter 13 is a stack of three disc-shaped filters about 20 mm thick that are held in the filter retainer 20. The material used for the filter 13 is a regenerative filter that can be washed and reused, such as a nonwoven fabric filter with a fiber-packed layer, a demister, a porous body (sponge or sintered metal fiber), a metal nonwoven fabric such as metal wool, or a glass fiber nonwoven fabric. Because clogging can be eliminated by washing the filter, waste can also be reduced, unlike disposable filters.

[0033] The three filters 13 may be made of the same material, or they may all be made of different materials. Also, it is possible to select the filter material appropriately according to the fine particles to be collected, such as by using a different material for only one filter. Here, a coarse dust-grade nonwoven fabric filter used for outdoor air treatment or as a prefilter for a medium-performance filter is selected.

[0034] 2, eight through holes 17 are provided in the outer periphery 13a of the filter 13, penetrating in the thickness direction. In addition, a cut 18 is provided between the through holes 17 and the outer edge 13b of the filter 13 on a line connecting the center point of the filter 13 and the center point of the through holes 17.

[0035] Filter retainer 20 is a rotor having a filter holding portion 21 that holds filter 13, a filter replacement portion 30, a contaminated airflow introduction portion 35, a rotation support portion 40 that rotatably supports filter retainer 20, and a protrusion portion 50.

[0036] First, the filter holding section 21 will be described. The filter holding section 21 has an upstream side annular member 22 and a downstream side annular member 23, which are plate-shaped, parallel to each other, and perpendicular to a rotation axis described later. Openings 22a and 23a are provided at the center of each of the annular members 22 and 23, respectively, to serve as paths for airflow. The upstream side annular member 22 and the downstream side annular member 23 are concentric and arranged coaxially with the drive shaft M1.

[0037] The diameter of the outer periphery of the annular portion of each of the upstream circular member 22 and the downstream circular member 23 is set to be larger for the downstream circular member 23, but the openings 22a and 23a have the same diameter (but are not limited to this).

[0038] The downstream side surface 22c of the upstream side circular ring member 22 and the upstream side surface 23b of the downstream side circular ring member 23 are arranged parallel to each other so as to face each other. Eight filter holding rods 24 are arranged at equal intervals around the periphery of the openings 22a, 23a between the upstream side circular ring member 22 and the downstream side circular ring member 23 so as to be perpendicular to each circular ring member 22, 23, and connect the upstream side circular ring member 22 and the downstream side circular ring member 23. The number of filter holding rods 24 is eight, which is an example, and may be two or three as long as it is strong enough to support the upstream and downstream side circular ring members and hold the filters. Also, the number of filter holding rods may be more than eight.

[0039] The filter 13 is inserted from the opening 23a of the downstream-side annular member 23, and the filter retaining rod 24 is fitted into the through-hole 17 of the filter 13 through the notch 18 that leads to the through-hole 17. The filter retaining rod 24 serves to position the filter 13 and also serves to prevent the filter 12 from flying out of the filter retainer 20 due to rotation.

[0040] The filter outer periphery 13a, in which the through hole 17 of the filter 12 is formed, is held in a state in which it is sandwiched between the periphery of the opening 22a of the upstream circular member 22 of the filter retainer 20 and the filter support member 26, and the periphery of the opening 23a of the downstream circular member 23 and the filter holder 25.

[0041] 3(a) and (d), a filter holder 25 for preventing the filter 13 from jumping out is detachably fixed to the downstream side surface 23c of the downstream-side circular member 23. The filter holder 25 has a disk portion 25a, which is smaller in diameter than the opening 23a and is coaxial with the opening 23a, in the center of the opening 23a of the downstream-side circular member 23, and a support member 25b on a diagonal line from the disk portion 25a to the opening 23a. 25b has a fan-shaped frame shape, but is not limited to this shape.

[0042] In addition, a small gap X is provided between the downstream side surface 23c of the downstream-side annular member 23 and the upstream side surface 8b of the second partition plate 8, and the gap X is made as small as possible in order to reduce the amount of cleaning liquid for cleaning the filter 13 that flows out downstream through this gap X.

[0043] Next, the filter replacement part 30 will be described. As shown in Fig. 3(a), a replacement bridge 31 is fixed to the downstream side surface 23c of the downstream-side circular member 23 so as to straddle the center of the opening 23a. The replacement bridge 31 has a shape that bridges over the opening 23a of the downstream-side circular member 23.

[0044] The replacement bridge 31 forms the filter replacement section 30 and is designed so that, when the maintenance door 12 is opened and the filter 13 is attached or detached from the filter retainer 20, the filter holder 25 can be inserted or removed by utilizing the space 31s below the bridge girder section 31a.

[0045] By providing a filter replacement part 30 downstream of the filter retainer 20 without providing a shaft penetrating the center of the filter 13, the filter 13 alone can be removed without removing and disassembling the filter retainer 20 from the casing 2, making maintenance significantly easier.

[0046] Next, the contaminated airflow introduction section 35 will be described. A cylindrical protruding rod 51, which is a protrusion 50 connected to the end of the filter holding rod 24, is provided on the upstream side surface 22b of the upstream circular ring member 22 of the filter retainer 20. A cylindrical rotating short tube 36 which constitutes the contaminated air flow introduction section 35 which guides the contaminated air flow from the contaminated air flow introduction chamber 3 to the retainer accommodating chamber 4 is provided on the inner circumference of the protrusion 51. A non-contact sealing circular ring member 37 which is provided concentrically with the upstream circular ring member 22 is fixed to the upstream end of the rotating short tube 36 and the protruding rod 51, connecting the upstream circular ring member 22 to the non-contact sealing circular ring member 37.

[0047] An opening 7a for introducing the contaminated air flow from the contaminated air flow introduction chamber 3 into the retainer accommodation chamber 4 is provided concentrically with the drive shaft M1 of the motor M in the first partition plate 7 between the retainer accommodation chamber 4 and the contaminated air flow introduction chamber 3. A cylindrical fixed short pipe 71 extending a short distance toward the downstream side is provided in the opening 7a, and together with the rotating short pipe 36 and the upstream most circular ring member 37, this constitutes the contaminated air flow introduction section 35.

[0048] As shown in Fig. 4(b), the diameter of the fixed short pipe 71 is set to be slightly smaller than the opening 37a of the non-contact sealing annular member 37. By projecting the tip of the fixed short pipe 71 downstream from the opening 37a of the non-contact sealing annular member 37, a small gap Y is formed between the opening 37a of the non-contact sealing annular member 37 and the fixed short pipe 71. The fixed short pipe 71 and the non-contact sealing annular member 37 function as a non-contact seal by the rotation of the filter retainer 20. This will be described in detail later.

[0049] Next, a description will be given of the filter rotation support part 40. A first rotating shaft fixing part 42 is provided at the center of the bridge girder part 31a of the replacement bridge 31. The first rotating shaft 41 is connected to the rotating shaft M2 and rotates the filter retainer 20.

[0050] The first rotating shaft 41 is connected to the rotating shaft M2 by a coupling 43. The first rotating shaft 41 is further rotatably supported by a first bearing portion 44 having a bearing 44a, and the first bearing portion 44 is supported by a bearing stand 45 fixed to the upstream side surface 9b of the third partition plate 9.

[0051] Further, in addition to the first rotating shaft 41, the filter retainer 20 also has a second rotating shaft 46 disposed on the upstream side, and the rotation of the filter retainer 20 is stably supported by being supported on both sides.

[0052] 3(c), a support member 26 is provided at the opening 22a of the upstream-side circular member 22 of the filter holding portion 21, and a disk portion 26a concentric with the drive shaft M1 of the motor M is provided at the center of the opening 22a. A second rotating shaft fixing portion 47 for fixing a second rotating shaft 46 is provided on the upstream side surface 26b of the disk portion 26a.

[0053] Furthermore, a support member (not shown) (similar to the support member 26 of the upstream annular member 22) is provided at the opening 7a of the first partition plate 7 that separates the retainer housing chamber 4 from the contaminated airflow introducing chamber 3, and a disk portion 7b is provided concentric with the opening 7a. A second bearing portion 48 that rotatably supports the second rotating shaft 46 is provided on the downstream side surface of the disk portion 7b.

[0054] The drive shaft M1, the rotating shaft M2, the first rotating shaft 41, and the second rotating shaft 46 are all arranged coaxially, and the filter retainer 20 is rotatably housed in the retainer housing chamber 4 by the drive of the motor M. In Fig. 1, all the shafts are arranged vertically, and for convenience, this is called a vertical type. Although not shown, if all the shafts are arranged horizontally, this is called a horizontal type.

[0055] Next, the protrusion 50 and the non-contact seal will be described. The protruding rod 51 constituting the protrusion 50 functions like a fan impeller together with the rotation of the filter retainer 20, generating a rotating airflow within the retainer housing chamber 4 and pushing the air within the retainer housing chamber 4 in the centrifugal direction, thereby increasing the pressure within the retainer housing chamber 4.

[0056] Additionally, the filter retaining rod 24 that fits into the through hole 17 of the filter 13 is also a protrusion 50 that fulfills the same function as the protrusion rod 51. Because the filter 13 is a coarse-dust grade nonwoven fabric with a large porosity, the filter retaining rod 24 also has the function of generating a rotating airflow in the retainer housing chamber 4 like the impeller of a fan, pushing out air in the centrifugal direction, although it is less efficient than the protrusion rod 51 that directly contacts the air in the retainer housing chamber 4 due to the rotation of the filter retainer 20.

[0057] Therefore, the pressure inside the retainer housing chamber 4 becomes higher than the pressure inside the contaminated air flow introducing chamber 3 (contaminated air flow introducing portion 35). The pressure inside the retainer housing chamber 4 increases in proportion to the rotation speed of the filter retainer, but for convenience, both cases where the pressure is relatively higher than the contaminated air flow introducing chamber 3 and where the pressure is higher than the actual atmospheric pressure are referred to as positive pressure Pp1.

[0058] The inside of the contaminated airflow introduction section 35 (contaminated airflow introduction chamber 3) is at a negative pressure Pn1 lower than atmospheric pressure due to the action of the fan F. The pressure inside the filter exchange chamber 5 downstream of the retainer housing chamber 4 is immediately before the fan F and is at a negative pressure Pn2 lower than the negative pressure Pn1. The space from the downstream side of the fan F to the exhaust port 16 is for discharging the clean airflow from the fan chamber 6 to the outside, and the pressure therein is a positive pressure Pp2. The pressure relationship between the chambers is Pn2 <Pn1<Pp1<Pp2となる。

[0059] As shown in Figure 4, the pressure inside the retainer accommodating chamber 4 is higher (positive pressure Pp1) than the contaminated air flow introduction chamber 3, so that it is possible to prevent the contaminated air flow from being short-circuited into the retainer accommodating chamber 4 without passing through the filter 13 through the gap Y provided between the opening 37a of the non-contact seal annular member 37 that constitutes the non-contact seal and the fixed short tube 71.

[0060] Thanks to the role played by the protrusion 50, even if the gap Y has a clearance of about several millimeters, the positive pressure Pn1 in the retainer housing chamber 4 can reliably prevent short-circuiting of the contaminated airflow.

[0061] Generally, contact seals such as O-rings and V-rings have high sliding resistance and therefore require large motor power, but by using a non-contact seal, the increase in power of the drive motor M for the filter retainer 20 can be minimized, resulting in energy savings.

[0062] In the first embodiment, the non-contact sealing annular member 37 is fixed to the upstream end of the rotating short pipe 36, but this is not limiting and it can also be provided to the downstream end of the fixed short pipe 71. In any case, it is sufficient that a gap Y is provided between the opening 37a of the non-contact sealing annular member 37 and the rotating or fixed short pipe.

[0063] Furthermore, there are two main mechanisms by which the efficiency of capturing fine particles is increased by rotating filter 13 at high speed. First, fine particles are captured by colliding with the fibers of filter 13, which rotate at a speed relatively faster than the speed at which the fine particles pass through filter 13. Second, when fine particles pass through filter 13, a strong centrifugal force is applied to the fine particles, which pushes the fine particles strongly toward the outer periphery, where they come into contact with the fibers of filter 13 and are captured.

[0064] By rotating a coarse-dust grade filter 13 such as a nonwoven fabric, which has conventionally been used as a prefilter, at high speed, it becomes possible to capture fine particles with diameters of less than 1 μm and even fine particles with diameters of less than 1 μm to 2 μm that would otherwise pass through without being captured by inertial collision alone.

[0065] Furthermore, the fine particles captured by the filter 13 are blown away by centrifugal force toward the radially outer periphery of the filter 13, so that the fine particles captured by the filter 13 are not re-scattered downstream by the progress of the air current. In addition, there is almost no increase in pressure loss of the filter 13, and the life of the filter 13 can be extended.

[0066] The collected particles are thrown outward in the radial direction by centrifugal force, and become large droplets or aggregates in the retainer housing chamber, which are then thrown into the retainer housing chamber 4 and collected as drain or particle aggregates. The collected particle aggregates or drain are discharged into the contaminated airflow introduction chamber 3 through a drain hole (not shown) in the first partition plate 7.

[0067] The pressure Pp1 in the retainer housing chamber 4 is higher than the pressure Pn1 in the contaminated airflow introduction chamber 3, and the contaminated airflow introduction chamber 3, which is the primary chamber, is located directly below the retainer housing chamber 4. Therefore, in addition to the effect of gravity, the aggregate or drain is smoothly discharged from the high-pressure chamber to the low-pressure chamber.

[0068] A drain pipe 80 is provided in the contaminated airflow introduction chamber 3, and the air is discharged to a drain chamber (not shown). Since the pressure inside the contaminated airflow introduction chamber 3 is a negative pressure Pn1 lower than atmospheric pressure, measures such as liquid sealing are taken in the drain chamber to prevent fine particles from flowing back into the contaminated airflow introduction chamber 3.

[0069] Next, the cleaning nozzle will be described. 81 shown in Fig. 1 is a cleaning nozzle. One or more cleaning nozzles 81 are provided on the upstream side of filter 13, and are used to clean filter 13 while filter 13 is held by filter retainer 20.

[0070] If the object to be collected is only mist (droplets) with high fluidity, they will coagulate inside the filter 13 without cleaning, and the self-cleaning effect of centrifugal separation can be fully expected. However, oil mist generated by cutting machine tools contains cutting chips, so the oil mist alone does not sufficiently clean the oil, and these occasionally accumulate inside the filter.

[0071] In addition, water-soluble cutting oil for machine tools can become viscous and gel-like when only the water evaporates. In that case, it cannot be separated by centrifugal separation and can accumulate in the filter 13. In addition, when collecting oil smoke from animal and vegetable oils in a fryer, the oil can oxidize on the surface of the filter 13 and become more viscous.

[0072] The cleaning nozzle 81 cleans the filter 13 by spraying cleaning liquid towards the filter 13 while rotating the filter retainer 20. The rotation speed may be the same as that during normal operation (when capturing fine particles), or it may be a slower rotation speed than during normal operation.

[0073] In cases where cutting chips are mixed in as described above, when solid particles such as fumes are to be collected, or when the material is viscous and self-cleaning action cannot be expected, it is possible to clean filter 13 without removing filter 13 by spraying a cleaning liquid suitable for the material to be collected from cleaning nozzle 81.

[0074] The cleaning liquid may be sprayed during normal operation (when collecting fine particles), and solid fine particles such as chips and fumes, as well as highly viscous cutting oil accumulated in the filter 13, are washed out by the cleaning liquid, move in the radial direction of the filter 13 together with the cleaning liquid due to centrifugal force, are shaken off within the retainer housing chamber 4, and are discharged as drain. The cleaning liquid is appropriately selected depending on the object to be collected, such as water, warm water, detergent, chemicals, and cleaning oil.

[0075] When the rotation speed is the same as during normal operation, the cleaning liquid tends to be quickly separated by centrifugal force in the upstream filter 13, but when the rotation speed is reduced, the cleaning liquid penetrates the downstream filter 13 thoroughly and exerts a cleaning effect. After the filter cleaning by the cleaning nozzle 81 is completed, the filter retainer 20 is rotated for a while to completely centrifuge the cleaning liquid retained in the filter 13.

[0076] Incidentally, the filter 13 is a disk-shaped filter with a thickness (about 20 mm) stacked in a direction perpendicular to the air flow, but the thickness and number of filters are not limited to this. Also, in addition to the disk shape, the filter may be polygonal (preferably a polygonal shape with a divisor or multiple of the number of filter holding rods), elliptical, or other shapes. The thickness of one filter may be about 30 mm, or may be 20 mm or less, but is not limited to these.

[0077] The number of filters may be one, two, four or more depending on the thickness of the filter. It can be changed according to the properties of the particles to be collected, the collection efficiency, and the pressure loss. In any case, the first filter 13 from the upstream side collects the most particles.

[0078] However, dividing the filter in this manner has the advantage that the height of the space 31s for filter replacement can be made low, and the filter can be easily washed.

[0079] Next, a second embodiment of the present invention will be described. Fig. 5 is a schematic cross-sectional view of a filter retainer 120, which is a rotating body according to the second embodiment of the present invention. Only the parts that differ from the first embodiment will be described here.

[0080] In the second embodiment, the protrusion 50 that stirs up the air in the retainer housing chamber 4 is made up of protrusion plates 151, and one protrusion plate 151 is fixed to the upstream side of the filter holding rod 24. The protrusion plate 151 is provided on the upstream side of the filter holding rod 24, but it may be provided in the midstream portion or downstream side, or it may be provided along the entire length of the filter holding rod 24. In any case, as the filter retainer 120 rotates, the protrusion plate 151 generates a rotating airflow in the retainer housing chamber 13, pushing the air outward, and increasing the pressure in the retainer housing chamber 4.

[0081] Moreover, filter 113 installed on the most downstream side (filter replacement chamber 5 side) of the three overlapping filters has a notch 117 along the filter holding rod 24 instead of a through hole, as shown in Fig. 5(b). The filter installed on the most upstream side, in the midstream section, may be filter 13' having through hole 17 of filter 13 shown in Fig. 2(a) but without outer periphery 13a (see Fig. 5(c)). Filter 13' has its outer periphery positioned by filter holding rod 24, making it easier to attach and detach filter 13' from filter retainer 120.

[0082] The filter retaining rod 24 is exposed on the outer periphery of the filter 13', and by rotation of the filter retainer 120, it also serves as a protruding rod, functioning as the protruding portion 50. The protruding portion provided on the outer periphery of the filter retaining rod 24 is not limited to the protruding plate 151. It may be a protruding rod, or may be something like a protruding blade, which will be described later.

[0083] Furthermore, the contaminated air flow introduction section 135 of the second embodiment is composed of a cylindrical rotary short pipe 136 provided from the opening 22a of the upstream annular member 22 toward the upstream side, and a cylindrical fixed short pipe 71 provided from the opening 7a of the first partition plate 7 toward the downstream side. The diameter of the rotary short pipe 136 is slightly larger than the diameter of the fixed short pipe 71 to form a gap Y1. However, this is not limited to this, and the diameter of the rotary short pipe 136 may be slightly smaller than the diameter of the fixed short pipe 71. In any case, a gap is formed in the portion where the tip of the rotary short pipe 136 and the tip of the fixed short pipe 71 overlap in the axial direction.

[0084] In the second embodiment, the second rotation shaft may be eliminated and the rotation shaft may be cantilevered.

[0085] 6 is a schematic diagram showing a third embodiment. The filter retainer 220 of the rotor according to the third embodiment is the same as that of the second embodiment, except that it does not have a contaminated airflow introduction section 35 (135). In the third embodiment, a gap Y2 is provided between the upstream side surface 22b of the upstream annular member 22 and the peripheral edge of the opening 7a of the first partition plate 7, forming a contactless seal.

[0086] 7 is a schematic diagram showing a fourth embodiment. In the fourth embodiment, there is no filter replacement chamber, and the filter retainer 320 of the rotor is not provided with a replacement bridge 31, so that the filter cannot be replaced from the downstream side. The downstream side of the retainer housing chamber 4 is partitioned by a second partition plate 108. An opening 108a is provided in the second partition plate 108, and a gap X1 is formed between the downstream side surface 123c of the periphery of the opening 123a of the downstream annular member 123 and the periphery of the opening 108a of the second partition plate 108.

[0087] A support member (not shown) is provided at the opening 123a of the downstream-side annular member 123, and a disk portion 125a is provided at the center of the support member. A first rotating shaft 141 is fixed to a first rotating shaft fixing portion (not shown) on the disk portion 125a.

[0088] A central shaft 90 is provided coaxially with the drive shaft M1 between the disk portion 125a and the disk portion 26a of the support member of the upstream-side circular member 22. A single rectangular filter 212 is wound around this central shaft 90 like toilet paper, or multiple filters are wound and overlapped concentrically. The wound or overlapped filter 212 can be held by a transparent belt, hook-and-loop fastener, or the like (not shown).

[0089] When replacing filter 212, a maintenance door (not shown) provided on the side of retainer housing chamber 4 is opened, and filter 212 is attached and detached from filter retainer 320 from the outer circumferential direction of filter 212. In other words, filter 212 can be replaced inside retainer housing chamber 4 without providing a filter replacement chamber for replacing filter 212, thereby realizing a more compact particulate interception device.

[0090] Furthermore, as for the protrusions, as shown in FIG. 7(a), curved protruding blades 252 are provided at equal intervals on the outer periphery of the rotary short tube 136.

[0091] 8 is a schematic diagram showing the fifth embodiment. In the filter retainer 420 of the rotor according to the fifth embodiment, the protruding blades 252, which are the protrusions, can be provided on the outer periphery of the permeable belt 124 that holds the outer periphery of the filter 212.

[0092] The protruding blade 252 which is the protruding portion may be the protruding plate 151 or the protruding rod 51.

[0093] In the first to fifth embodiments, one motor M rotates both the fan F and the filter retainer 20, but it is also possible to provide separate drive motors for the fan F and the filter retainer 20. In any case, by configuring the sealing between the contaminated airflow introduction chamber 3 and the retainer housing chamber 4 to be non-contact, the increase in power of the drive motor M for the filter retainer 20 can be minimized, which also leads to energy savings.

[0094] Incidentally, the seal formed by the downstream side surface 23c (123c) of the downstream circular member 23 (123) and the peripheral edge of the opening 8a (108a) of the second partition plate 8 (108) does not necessarily have to be non-contacting, but may also be a contact seal utilizing a lip seal such as a V-ring.

[0095] Also, although not shown, for example, in the case of a horizontal type particulate collector, a drain hole can be provided directly in the retainer housing chamber 13 to discharge the particulates to the outside of the device. During normal operation, the rotation speed of the filter retainer 20 is 3000 rpm or more, and the positive pressure Pn1 in the retainer housing chamber 13 becomes higher than atmospheric pressure due to the protrusions, making it possible to discharge the particulates without sealing the drain pipe with liquid. Note that 3000 rpm is an example and is not limited to this. The rotation speed, the number, shape, and position of the protrusions can be appropriately selected so that the pressure in the retainer housing chamber 4 becomes higher than atmospheric pressure.

[0096] 1 shows an example in which the introduction section 10 of the contaminated airflow introduction chamber 3 is connected to a duct, but instead of the introduction section 19, for example, the contaminated airflow introduction chamber 3 can be directly installed on a cover (partition plate) surrounding the machining chamber of the machine tool, making it a bin-mounted type. Alternatively, the machining chamber of the machine tool itself can be used as the contaminated airflow introduction chamber, and the retainer housing chamber 4 can be installed thereon. [Explanation of symbols]

[0097] 1 Particulate collection device 2 Casing 3. Contaminated airflow introduction chamber 4 Retainer Containment Room 5. Filter replacement room 6 Fan Room 7 First Partition 8, 108 Second partition plate 9 Third partition plate 12 Maintenance door 13 Filters 16 Outlet 20, 120, 220, 320, 420 Filter Retainer 24 Filter retaining rod 25 Filter holder 31 Replacement Bridge 41, 141 First rotating shaft 46 Second Rotating Axis 50 (24, 51, 151, 252) Protrusions (filter holding rod, protruding rod, protruding plate, protruding blade) 80 Drain piping 81 Cleaning nozzle 90 center axis Medium motor M1 Motor drive shaft M2 rotation axis

Claims

1. The particulate collector is one or more filters for capturing particulate matter contained in the polluted air stream; a filter retainer that is a rotating body that holds the filter, The filter retainer includes: A filter holder that holds the filter; A rotation support portion connected to a drive shaft of the motor; and one or more protrusions provided on an outer periphery of the filter retainer, and the filter retainer is rotatably accommodated in a retainer accommodating chamber, The retainer housing has a first partition plate on an upstream side having an opening and a second partition plate on a downstream side having an opening, When the contaminated airflow is caused to flow into the retainer housing chamber from the opening of the first partition plate and the clean airflow is caused to flow out from the opening of the second partition plate, A particulate matter collecting device, characterized in that, when the filter retainer is rotated by the motor, the first partition plate and the filter retainer function as a seal for the contaminated airflow.

2. The particulate matter collection device according to claim 1, characterized in that the filter is a regenerative filter, the filter holding portion has an upstream circular member and a downstream circular member, the filter is sandwiched between the upstream circular member and the downstream circular member, and a gap is provided between the upstream circular member and the first partition plate, so as to function as a non-contact seal when the filter retainer is rotated.

3. The particulate matter collection device according to claim 1, characterized in that the filter is a regenerative filter, the filter holding portion has an upstream circular member and a downstream circular member, the filter is sandwiched between the upstream circular member and the downstream circular member, a rotating short tube protruding upstream from an opening of the upstream circular member and a fixed short tube protruding downstream from an opening of the first partition plate are arranged concentrically, the tip of the rotating short tube and the tip of the fixed short tube are arranged to overlap in the axial direction to form a contaminated air flow introduction portion, and there is a gap between the tip of the fixed short tube and the tip of the rotating short tube, which functions as a non-contact seal when the filter retainer is rotated.

4. 2. The particulate collection device according to claim 1, wherein the filter is a regenerative filter, the filter holding portion has an upstream side circular member and a downstream side circular member, the filter is sandwiched between the upstream side circular member and the downstream side circular member, a rotating short tube protruding upstream from an opening of the upstream side circular member and a fixed short tube protruding downstream from an opening of the first partition plate are concentrically arranged, the tip of the rotating short tube and the tip of the fixed short tube are arranged to overlap in the axial direction, and further, a non-contact sealing circular member is arranged horizontally concentrically on the upstream side circular member at the tip of the rotating short tube or the fixed short tube to form a contaminated air flow introduction portion, and a gap is provided between the opening of the non-contact sealing circular member and the fixed short tube or the rotating short tube, so that the particulate collection device functions as a non-contact seal when the filter retainer is rotated.

5. The particulate matter collection device of claim 1, characterized in that the filter is a regenerative filter, the filter holding portion has an upstream circular member and a downstream circular member, the filter is sandwiched between the upstream circular member and the downstream circular member, the downstream circular member is provided with a replacement bridge or a support member disc portion for the downstream circular member, and the replacement bridge or the support member disc portion for the downstream circular member is provided with a rotating shaft fixing portion which is the rotating support portion to which a first rotating shaft connected to the drive shaft of the motor is fixed.

6. The particle collection device described in claim 2, characterized in that a replacement bridge or a support member disk portion of the downstream circular member is provided on the downstream circular member, and a rotating shaft fixing portion which is the rotation support portion to which a first rotating shaft connected to the drive shaft of the motor is fixed is provided on the replacement bridge or the support member disk portion of the downstream circular member.

7. The particle collection device described in claim 3, characterized in that a replacement bridge or a support member disk portion of the downstream circular member is provided on the downstream circular member, and a rotating shaft fixing portion which is the rotation support portion to which a first rotating shaft connected to the drive shaft of the motor is fixed is provided on the replacement bridge or the support member disk portion of the downstream circular member.

8. The particle collection device described in claim 4, characterized in that a replacement bridge or a support member disk portion of the downstream circular member is provided on the downstream circular member, and a rotating shaft fixing portion which is the rotation support portion to which a first rotating shaft connected to the drive shaft of the motor is fixed is provided on the replacement bridge or the support member disk portion of the downstream circular member.

9. The particulate matter collection device described in claim 5, characterized in that a filter replacement chamber is provided downstream of the retainer accommodating chamber via the second partition plate, a maintenance door is provided on the side of the filter replacement chamber, a plurality of filter holding rods are provided between the upstream circular member and the downstream circular member parallel to the rotation shaft of the motor, the filters have a circular plate shape, at least one of the filters has a through hole with a notch or cutout in its outer periphery and is positioned on the filter holding rod, and the filter holding rod is the protrusion.

10. The particulate matter collection device described in claim 6, characterized in that a filter replacement chamber is provided downstream within the retainer accommodating chamber via the second partition plate, a maintenance door is provided on the side of the filter replacement chamber, a plurality of filter holding rods are provided between the upstream circular member and the downstream circular member parallel to the rotation shaft of the motor, the filters have a circular plate shape, at least one of the filters has a through hole with a notch or cutout in its outer periphery and is positioned on the filter holding rod, and the filter holding rod is the protrusion.

11. The particulate matter collection device described in claim 7, characterized in that a filter replacement chamber is provided downstream of the retainer accommodating chamber via the second partition plate, a maintenance door is provided on the side of the filter replacement chamber, a plurality of filter holding rods are provided between the upstream circular member and the downstream circular member parallel to the rotation shaft of the motor, the filters have a circular plate shape, at least one of the filters has a through hole with a notch or cutout in its outer periphery and is positioned on the filter holding rod, and the filter holding rod is the protrusion.

12. The particulate matter collection device described in claim 8, characterized in that a filter replacement chamber is provided downstream of the retainer accommodating chamber via the second partition plate, a maintenance door is provided on the side of the filter replacement chamber, a plurality of filter holding rods are provided between the upstream circular member and the downstream circular member parallel to the rotation shaft of the motor, the filters have a circular plate shape, at least one of the filters has a through hole with a notch or cutout on its outer periphery and is positioned on the filter holding rod, and the filter holding rod is the protrusion.

13. The particulate matter intercepting device according to claim 9 or 10, wherein the filter holding rod is further provided on an outer periphery thereof with the protruding portion being any one of a protruding rod, a protruding plate, and a protruding blade.

14. The particulate matter intercepting device according to claim 11 or 12, characterized in that the outer circumferential side of the filter holding rod or the outer circumferential side of the rotating short tube is further provided with a protruding portion, which is either a protruding rod, a protruding plate, or a protruding blade.

15. A particulate matter collection device as described in any one of claims 1 to 4, characterized in that a maintenance door is provided on a side of the retainer housing chamber, the filter holding portion has a central axis coaxial with the drive shaft of the motor, and the filter is one or more regenerative filters wound or overlappingly wound around the central axis.

16. The particle collection device described in any one of claims 2 to 4, characterized in that a support member disc portion is provided on the downstream circular member, and a rotating shaft fixing portion which is the rotation support portion to which a first rotating shaft connected to the drive shaft of the motor is fixed is provided on the support member disc portion of the downstream circular member, a maintenance door is provided on the side of the retainer accommodating chamber, the filter holding portion has a central axis coaxial with the drive shaft of the motor, and the filter is one or more regenerative filters wound or stacked around the central axis.

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