JP2024063284A - Cyclone Separator - Google Patents

Abstract

To provide a cyclone separation device that reduces pressure loss in generating a swirl airflow.SOLUTION: A cyclone separation device (ventilation port hood) comprises a plurality of fixed blades 8 for generating a swirl airflow in a housing using air flowing in from an inflow port. The plurality of fixed blades 8 respectively has: a straight shape part 81 of a prescribed thickness, which includes an end 83 of a downstream side and an end 85 on an upstream side, and which is arranged by being inclined to a prescribed angle (angle D1) relative to a straight line L1 connecting a central axis 6 and a midpoint of the end 83 of the downstream side, in a cross-sectional shape of the fixed blade 8 according to a plane view with the central axis 6 of a swirl chamber as the normal line; and a curved shape part 82 which is provided by extending to the upstream side from the straight shape part 81, and in which the end 85 of the upstream side is curved to an external surface S1 side of the fixed blade 8 beyond the straight shape part 81. The plurality of fixed blades 8 are arranged at a prescribed interval along the circumference of a cylinder (cylinder surface A1) with the central axis 6 of the swirl chamber as its center.SELECTED DRAWING: Figure 5

Description

The present invention relates to a cyclone separator that uses centrifugal force to separate foreign matter contained in the air.

Conventionally, this type of cyclone separator has been attached to the air intake vent on the exterior wall of a house to separate insects and dust (hereafter referred to as foreign matter) that are sucked in along with the outside air when it is taken into the house.

Conventionally, this type of cyclone separation device is known, for example from Patent Document 1. Figure 8 is an external perspective view of a conventional cyclone separation device.

As shown in FIG. 8, one axial end face has a circular inlet 102 with multiple fixed blades 101 arranged radially with equal intervals between them, and the other end face has a circular outlet (coaxial with the inlet 102 and on the rear side of the figure), and the space between the inlet 102 and the outlet is a cylindrical swirling chamber 103, where air entering through the inlet 102 becomes a swirling air current due to the fixed blades 101, and the air current then flows out from the outlet. Below the swirling chamber 103, there is a separation chamber 104 that contains foreign matter in the air that has been separated by the swirling air current.

JP 2008-36579 A

In conventional cyclone separation devices, the air sucked in from the inlet 102 is swirled inside the device by the fixed blades 101, which can easily cause turbulence in the airflow due to the shape of the fixed blades 101, resulting in large pressure losses. From this perspective, there is room for further improvement in the fixed blades 101.

The present invention aims to provide a cyclone separation device that can reduce pressure loss when generating a swirling airflow.

To achieve this objective, the cyclone separation device of the present invention comprises an inlet for allowing air to flow into a housing, a plurality of fixed blades for generating a swirling air current within the housing by the air flowing in from the inlet, an outlet provided on the rear surface of the housing for discharging the air that has flowed in from the inlet to the outside of the housing, a space dividing plate for dividing the interior of the housing into a swirling chamber that is connected to the inlet and is located on the inner periphery including the center of the housing, and a separation chamber that is located on the outer periphery side of the swirling chamber, a through hole provided in the space dividing plate for connecting the separation chamber to the swirling chamber, and an exhaust port provided below the separation chamber in the direction of gravity when the central axis of the housing is positioned horizontally, for connecting the separation chamber to the outside of the housing. In the cyclone separation device, each of the multiple fixed blades has a downstream end and an upstream end, and in the cross-sectional shape of the fixed blade in a plane normal to the central axis of the swirl chamber, it is configured with a linear portion of a specified thickness arranged at a specified angle with respect to a line connecting the central axis and the midpoint of the downstream end, and a curved portion extending upstream from the linear portion, the upstream end of which is curved toward the outer surface of the fixed blade more than the linear portion, and the multiple fixed blades are arranged at specified intervals along the circumference of a cylinder centered on the central axis of the swirl chamber, on the back side of the swirl chamber, thereby achieving the intended purpose.

The present invention provides a cyclone separation device that can reduce pressure loss when generating a swirling air current.

FIG. 1 is a perspective view of a ventilation hood according to a first embodiment of the present invention, as viewed obliquely from below and from the front side. FIG. 2 is a side cross-sectional view of the ventilation hood according to the first embodiment. FIG. 3 is a detailed view of a rectangular separator that constitutes the ventilation hood according to the first embodiment. FIG. 4 is a perspective view of a fixed blade that constitutes the ventilation opening hood according to the first embodiment. FIG. 5 is a front cross-sectional view of a fixed blade that constitutes the ventilation opening hood according to the first embodiment. Figure 6(a) is a front cross-sectional view showing the air flow around the fixed blades that make up the ventilation hood of embodiment 1, and Figure 6(b) is a front cross-sectional view showing the air flow around the fixed blades that make up the ventilation hood of the comparative example. Figure 7(a) is a front cross-sectional view of a fixed blade that constitutes a ventilation hood in accordance with embodiment 2 of the present invention, and Figure 7(b) is a front cross-sectional view showing the air flow around the fixed blade that constitutes the ventilation hood. FIG. 8 is a perspective view showing the appearance of a conventional cyclone separator.

The cyclone separation device according to the present invention comprises an inlet for allowing air to flow into a housing, a plurality of fixed blades for generating a swirling air current within the housing by the air flowing in from the inlet, an outlet provided on the rear surface of the housing for discharging the air flowing in from the inlet to the outside of the housing, a space dividing plate for dividing the interior of the housing into a swirling chamber which is connected to the inlet and located on the inner periphery including the center of the housing, and a separation chamber which is located on the outer periphery side of the swirling chamber, a through hole provided in the space dividing plate for connecting the separation chamber to the swirling chamber, and an exhaust port provided below the separation chamber in the direction of gravity when the central axis of the housing is positioned horizontally, for connecting the separation chamber to the outside of the housing. In the cyclone separation device, each of the multiple fixed blades has a downstream end and an upstream end, and in the cross-sectional shape of the fixed blade in a plane normal to the central axis of the swirl chamber, it is configured with a linear portion of a specified thickness arranged at a specified angle with respect to a line connecting the central axis and the midpoint of the downstream end, and a curved portion extending upstream from the linear portion, the upstream end of which is curved toward the outer surface of the fixed blade more than the linear portion, and the multiple fixed blades are arranged at specified intervals on the back side of the swirl chamber along the circumference of a cylinder centered on the central axis of the swirl chamber.

With this configuration, when air flowing into the housing from outside through the inlet is deflected by the fixed blades, it is deflected gradually along the curved portion of the fixed blade to the straight portion, suppressing separation of the air flow on the inner surface of the fixed blade. This reduces pressure loss caused by separation of the air flow. In other words, it is possible to create a cyclone separation device that can reduce pressure loss when generating a swirling air current.

In the cyclone separation device according to the present invention, the curved portion may have a predetermined curvature rate, and may be curved so that the tangent to the inner surface of the fixed blade at the upstream end is parallel to a straight line connecting the central axis and the midpoint of the upstream end. In this way, in a plane normal to the central axis of the swirl chamber, air sucked from the space outside the housing toward the central axis flows along the curved portion at the upstream end of the fixed blade, suppressing separation of the air flow on the inner surface of the fixed blade, thereby reliably reducing pressure loss.

In the cyclone separation device according to the present invention, the cross-sectional shape of the fixed blades may be configured such that the curved portion has a shorter length between the upstream and downstream sides than the straight portion. As a result, the longer the straight portion, the easier it is for the fixed blades to deflect the air, making it easier to generate a more swirling airflow. On the other hand, the shorter the length between the upstream and downstream ends of the fixed blades, the smaller the friction with the air. This makes it possible to more reliably reduce pressure loss when generating a swirling airflow to separate foreign matter.

In the cyclone separation device according to the present invention, the predetermined thickness of the linear portion may be configured to become thinner from the upstream side to the downstream side of the linear portion. This reduces the space between the airflow flowing through the downstream end of the fixed blade on the outer surface side and the airflow flowing through the downstream end of the fixed blade on the inner surface side at the downstream end of the fixed blade, suppressing turbulence caused by the airflows that meet at the downstream end of the fixed blade, and further reducing pressure loss when generating a swirling airflow.

The following describes an embodiment of the present invention with reference to the drawings.

(Embodiment 1)
In this embodiment, the cyclone separating device will be described below based on an example in which it is applied to a ventilation hood.

Figure 1 is a perspective view of a ventilation hood 1 according to embodiment 1 of the present invention, viewed from diagonally below and in front.

The ventilation hood 1 shown in Figure 1 is installed on the exterior wall of a house and is attached to an air intake that draws outdoor air into the house.

The device (not shown) that takes in outdoor air into the house includes a blower (not shown) installed inside the house and a ventilation duct (not shown), which connects the blower to the ventilation hood 1. This allows air that has passed through the ventilation hood 1 to be introduced into the room. When taking in outdoor air into the house, the ventilation hood 1 separates foreign matter contained in the air by using the centrifugal force of the swirling air current generated around the central axis 6.

The ventilation hood 1 is connected to the ventilation duct using the outlet pipe 2 and is installed protruding from the exterior wall of the house.

Next, we will explain the external configuration of the ventilation hood 1.

The ventilation hood 1 comprises a housing 5, fixed blades 8, and an exhaust section 11.

The housing 5 has a hexahedral shape and is made up of a cover 3 on the front side and a base plate 4 on the back side.

The cover 3 is a rectangular box that covers the front side of the housing 5, and the four sides have openings on the rear side as inlet ports 7. Note that the front surface in FIG. 1, i.e., the front surface of the ventilation hood 1, is flat, but it may also be dome-shaped with a protruding center.

The base plate 4 has a circular opening in the center, to which the outlet pipe 2 is connected. The air inside the cover 3 flows out from the outlet port 9 at one end of the outlet pipe 2. The base plate 4 is adjacent to the side of the cover 3, and the housing 5 forms the outer shell of the ventilation hood 1.

The fixed blades 8 are components that generate a swirling air current inside the housing 5 by the air flowing in from the inlet 7. The fixed blades 8 are arranged at equal intervals and rotationally symmetrically with respect to the central axis 6 on the downstream side of the inlet 7 as a swirling flow generating means for swirling the incoming air. Details will be described later.

In addition, netting may be provided around the inlet 7 and the outer periphery of the fixed blades 8 to prevent large insects or birds from entering the device.

The discharge section 11 is provided at the bottom of the cover 3 so as to protrude from the side when the central axis 6 is positioned substantially horizontally. More specifically, the discharge section 11 has a discharge promotion surface 10 and a discharge port 12.

The exhaust promotion surface 10 is made up of two surfaces arranged symmetrically, and is connected to two other surfaces to form an exhaust port 12 that is always open at the bottom. The exhaust promotion surface 10 is inclined in a direction in which the cross-sectional area becomes smaller toward the bottom, and is provided with an exhaust port 12 at the tip that opens to connect the inside and outside of the ventilation hood 1.

The exhaust outlet 12 is an opening provided at the lower end of the exhaust section 11 to connect the inside and outside of the ventilation hood 1, and is a rectangle that is long in the direction of the central axis 6. The long and narrow shape makes it difficult for large insects or birds to enter, and increases the area that makes it easier to exhaust separated foreign matter. Furthermore, the exhaust outlet 12 is long in the direction of the central axis 6 in order to increase the exhaust effect by natural wind, which will be described later.

The discharge promotion surface 10 has a symmetrical structure so that the same discharge promotion effect can be obtained regardless of whether the natural wind is blowing from the left or right. Also, while the discharge promotion surface 10 needs to have an incline on both the left and right sides, it does not have to be strictly symmetrical, and the angle can be slightly different. In particular, in this embodiment, the discharge promotion surface 10 has a smooth surface that gradually becomes steeper, like an inverted Mt. Fuji, so that the natural wind that hits the discharge promotion surface 10 can smoothly change direction.

Next, the internal configuration of the device will be described with reference to Figures 2 and 3. Figure 2 is a side cross-sectional view of the ventilation hood 1 according to the first embodiment. Figure 3 is a detailed view of the rectangular separator 19 that constitutes the ventilation hood 1 according to the first embodiment. Figure 3 shows the positional relationship between the cover 3 and the rectangular separator 19.

When the discharge section 11 is positioned at the bottom of the cover 3, as shown in FIG. 2, the internal space surrounded by the cover 3 and the base plate 4 contains the fixed blades 8, the inner tube 17, the space dividing plate 13, and the rectangular separator 19.

The inner tube 17 and the fixed blades 8 are connected to the base plate 4. With the inner tube 17 on the inside, the inner tube 17 and the fixed blades 8 are arranged concentrically with respect to the central axis 6.

The inner tube 17 is a tube that communicates with the outflow tube 2. The inner tube 17 is provided on the opposite side of the base plate 4 so as to communicate with the outflow port 9. The inner tube end surface 18 of the inner tube 17 is located inside the cover 3, closer to the front side of the cover 3 than the fixed blade 8. In other words, it is located on the far side of the fixed blade 8 in the direction of the central axis 6. In this embodiment, the inner diameter of the inner tube 17 is different from the inner diameter of the outflow tube 2 in the base plate 4 portion, and the inner diameter of the inner tube 17 is smaller than the inner diameter of the outflow tube 2, but they may be the same size. Since a sudden expansion occurs on the outflow tube 2 side in the base plate 4 portion, if airflow turbulence is expected, the shape may be such that it gradually expands.

As shown in FIG. 3, the rectangular separator 19 is a plate with an opening 20 in the center, which is disposed perpendicular to the central axis 6 and divides the internal space in two. As shown in FIG. 2, the rectangular separator 19 has the fixed blade 8 connected to one side and the space dividing plate 13 connected to the other side. In other words, the fixed blade 8, the rectangular separator 19, and the space dividing plate 13 are disposed in that order within the internal space surrounded by the cover 3 and the base plate 4. The inlets 7, which are provided on the four sides of the cover 3 facing the fixed blade 8, are disposed on the back side of the cover 3, with the rectangular separator 19 as a boundary, as shown in FIG. 3. As a result, the fixed blades 8 and the inlets 7 face each other.

The space dividing plate 13 is a cylinder whose axis is aligned with the direction of the central axis 6, and divides the inside of the cover 3 into an inside and an outside. More specifically, the space dividing plate 13 divides the inside of the housing 5 (cover 3) into a swirling chamber 14 that communicates with the inlet 7 and is located on the inner periphery side including the center of the housing 5 (cover 3), and a separation chamber 15 that is located on the outer periphery side of the swirling chamber 14. The cross section (plane direction perpendicular to the central axis 6) of the swirling chamber 14 formed inside the space dividing plate 13 is a truncated cone shape with an inclined side surface, with the cross-sectional area expanding toward the base plate 4 side inside the cover 3. It is to be noted that the shape may be a cylinder with a constant cross-sectional area.

As described above, the inside of the space dividing plate 13 is the swirl chamber 14 including the center of the cover 3, and the outer peripheral side closer to the side of the cover 3 on the outside of the space dividing plate 13 (the space surrounded by the space dividing plate 13 and the cover 3) is the separation chamber 15. In addition, a through hole 16 is provided in the space dividing plate 13, and the swirl chamber 14 and the separation chamber 15 are connected via the through hole 16.

The through hole 16 is an opening provided in the space dividing plate 13 that connects the separation chamber 15 and the swirl chamber 14. The through hole 16 is provided at a position on the front side of the cover 3 and above the central axis 6 when the central axis 6 is positioned approximately horizontally.

Next, the fixed blades 8 will be described in detail with reference to Figures 4 and 5. Figure 4 is a perspective view of the fixed blades 8 constituting the ventilation hood 1 according to the first embodiment. Figure 5 is a front cross-sectional view of the fixed blades 8 constituting the ventilation hood 1 according to the first embodiment. The front cross-sectional view of Figure 5 corresponds to the cross-sectional shape of a plane normal to the central axis 6 of the housing 5 (swirl chamber 14).

The fixed blades 8 are provided downstream of the inlet 7 as a swirling flow generating means for swirling the incoming air. As shown in FIG. 4, the fixed blades 8 are arranged at equal intervals in rotational symmetry with respect to the central axis 6, standing parallel to the front side of the base plate 4 and tilted at a predetermined angle (angle D1) with respect to a radial line L1 passing through the central axis 6. It can also be said that the fixed blades 8 are arranged at predetermined intervals on the rear side of the swirling chamber 14 along the circumference of a cylinder centered on the central axis 6 of the swirling chamber 14.

Each of the fixed blades 8 has an outer surface S1 facing outward (the side opposite the central axis 6) and an inner surface S2 facing inward (the side toward the central axis 6). In addition, the fixed blade 8 includes a linear portion 81 of a predetermined thickness and a curved portion 82 extending from the upstream side of the linear portion 81 and curved toward the outer surface S1.

More specifically, as shown in FIG. 5, each of the fixed blades 8 has a downstream end 83 and an upstream end 85, and is configured with a linear portion 81 of a predetermined thickness that is inclined at a predetermined angle with respect to a straight line L1 that connects the central axis 6 and the midpoint of the end 83, and a curved portion 82 that extends upstream from the linear portion 81 and has an end 85 that is curved toward the outer surface S1 of the fixed blade 8 relative to the linear portion 81.

The linear portion 81 is rectangular with a downstream end 83 and an upstream end 84. The linear portion 81 has a predetermined thickness. The midpoint of the end 83 of the linear portion 81 is at the intersection of a cylindrical surface A1 centered on the central axis 6 and a radial line L1 passing through the central axis 6, and the linear portion 81 is positioned such that a line L3 passing through the midpoint of the end 83 and the midpoint of the end 84 is inclined at an angle D1 with respect to the line L1.

The curved portion 82 is an arc shape that connects the downstream end 84 and the upstream end 85 with a predetermined curvature. In other words, the end 84 is the upstream end of the straight portion 81 and also the downstream end of the curved portion 82. The midpoint of the end 85 of the curved portion 82 is on a cylindrical surface A2 that is larger than the cylindrical surface A1 centered on the central axis 6, and is disposed on the outer surface S1 side than the straight line L3. In addition, the end 85 is tangent to the cylindrical surface A2 and is a line segment perpendicular to the straight line L2 that passes through the end 85 and the central axis 6. The curve on the outer surface S1 side and the curve on the inner surface S2 side that connect the end 84 and the end 85 each have a constant curvature, and the end 84 and the end 85 perpendicularly intersect with the outer surface S1 and the inner surface S2, respectively. In other words, the curved portion 82 is smoothly connected to the straight portion 81 at the end 84, and the tangent line L4 on the inner surface S2 side at the end 85 is parallel to the straight line L2.

The length of the curved portion 82 is configured to be shorter than that of the straight portion 81. In other words, the distance between the midpoint of end 85 and the midpoint of end 84 is smaller than the distance between the midpoint of end 84 and the midpoint of end 83.

Next, we will explain the air flow in the above configuration with reference to Figure 2.

When the blower (not shown) is operated, outdoor air containing foreign matter flows into the ventilation hood 1 through the inlet 7. It becomes a swirling air current by passing through the fixed blades 8, and because the inner tube 17 is positioned closer to the front of the ventilation hood 1 than the inlet 7, it swirls in the swirling chamber 14 while heading toward the front of the ventilation hood 1. Here, the foreign matter moves toward the space dividing plate 13 due to centrifugal force, and moves into the separation chamber 15 as it passes near the through hole 16. The air from which the foreign matter has been separated flows into the inner tube 17, passes through the outlet tube 2, and flows out of the device from the outlet 9.

The foreign matter that has moved into the separation chamber 15 is temporarily stored therein. Because the blower creates a negative pressure inside the ventilation hood 1 relative to the outside of the ventilation hood 1, air also flows into the separation chamber 15 from the exhaust port 12. The air that has flowed in passes through the through hole 16 and flows into the swirling chamber 14, where it merges with the swirling air current inside the swirling chamber 14.

When natural wind blows on the outdoor side of the discharge port 12, the static pressure on the outdoor side of the discharge port 12 drops, and when it becomes lower than the static pressure on the separation chamber 15 side, the separated foreign matter is pulled out to the outdoors. As a result, the foreign matter is automatically discharged to the outdoors, so that the foreign matter does not continue to accumulate in the separation chamber 15, and maintenance to remove the accumulated matter is not required.

Next, the air flow passing through the fixed blade 8 will be described with reference to Figure 6. Figure 6(a) is a front cross-sectional view showing the air flow around the fixed blade 8 constituting the ventilation hood 1 according to the first embodiment, and Figure 6(b) is a front cross-sectional view showing the air flow around the fixed blade 8x constituting the ventilation hood according to the comparative example.

As shown in FIG. 6(a), the airflow 30 flowing in from the inlet 7 flows toward the central axis 6 in a radial manner centered on the central axis 6. A part of the airflow 30, the airflow 31a, flows along the outer surface S1 of the fixed blade 8 and is deflected in a direction parallel to the straight line L3. Meanwhile, another part of the airflow 30, the airflow 31b, passes through the inner surface S2 side from the upstream end 85 of the fixed blade 8. That is, the airflow 31b flows into the inner surface S2 side along the tangent line L4. At this time, the area between the airflow 31b and the inner surface S2 is under negative pressure relative to the surroundings, so the airflow 31b flows along the inner surface S2 and is deflected in a direction parallel to the straight line L3 on the inner surface S2 side. Then, on the downstream side of the fixed blade 8, the airflow 31a and the airflow 31b join together and flow into the swirling chamber 14 as the airflow 32, generating a swirling airflow as the airflow 32 deflected by the multiple fixed blades 8.

In contrast, in the case of a comparative ventilation hood having fixed blades 8x that do not have curved portions and are composed only of straight portions, as shown in FIG. 6B, the airflow 40 flowing in from the inlet 7 flows radially toward the central axis 6, centered on the central axis 6. A part of the airflow 40, airflow 41a, flowing into the fixed blades 8x flows along the outer surface S3 that is the outside of the fixed blades 8x and is deflected in a direction parallel to the straight line L3. Meanwhile, another part of the airflow 40, airflow 41b, passes through the inner surface S4 side that is inside the upstream end 85x of the fixed blade 8x. In other words, the airflow 41b flows into the inner surface S2 side along the straight line L2. At this time, on the upstream side of the inner surface S4, an angle is formed between the tangent line of the inner surface S4 (a straight line parallel to the straight line L3) and the inflow direction of the passing airflow 40 (a direction along the straight line L2), so that the airflow 41b separates on the inner surface S2 side of the fixed blade 8x, and a negative pressure area SA1 is generated between the airflow 41b and the inner surface S4. The greater the flow speed of the airflow 40 (i.e., the airflow 41b), the larger the negative pressure area SA1 becomes, which causes pressure loss in the airflow 41b. Finally, the airflow 41b flows along the inner surface S2 and is deflected in a direction parallel to the straight line L3 on the inner surface S2 side. The deflected airflow 41a and the deflected airflow 41b then join together to become the airflow 42, which flows as a swirling airflow.

As described above, in the ventilation hood 1 according to this embodiment, the fixed blades 8 are provided with a curved portion 82 on the upstream side, so that the airflow 31b flows in a manner that suppresses the formation of a negative pressure area SA1 caused by the separation of the air flow between the airflow 30 (i.e., the airflow 31) and the inner surface S2 side of the fixed blades 8. In other words, the ventilation hood 1 can reduce pressure loss when generating a swirling airflow.

As described above, the ventilation hood 1 according to the first embodiment provides the following advantages:

(1) The ventilation hood 1 comprises an inlet 7 for admitting air into a housing 5 consisting of a cover 3 and a base plate 4, a plurality of fixed blades 8 for generating a swirling air current within the housing 5 by the air flowing in from the inlet 7, an outlet 9 for connecting to a ventilation duct provided on the base plate 4, a rectangular separator 19 and a space dividing plate 13 for dividing the interior of the housing 5 into a swirling chamber 14 and a separation chamber 15, a through hole 16 provided in the space dividing plate 13, and an exhaust section 11 provided at a position below the separation chamber 15 in the direction of gravity when the central axis 6 of the housing 5 is positioned horizontally, and connecting the separation chamber 15 to the outside of the housing. Each of the multiple fixed blades 8 has a downstream end 83 and an upstream end 85, and in the cross-sectional shape of the fixed blade 8 in a plane normal to the central axis 6 of the swirl chamber 14, it is configured to have a linear portion 81 of a predetermined thickness arranged at a predetermined angle D1 with respect to a straight line L1 connecting the central axis 6 and the midpoint of the downstream end 83, and a curved portion 82 extending upstream from the linear portion 81, whose upstream end 85 is curved toward the outer surface S1 of the fixed blade 8 more than the linear portion 81. The multiple fixed blades 8 are configured to be arranged at predetermined intervals along a cylindrical surface A1 centered on the central axis 6 of the swirl chamber 14 on the back side of the swirl chamber 14.

In other words, the ventilation hood 1 includes an inlet 7 for allowing air to flow into the housing 5, a plurality of fixed blades 8 for generating a swirling air current within the housing 5 by the air flowing in from the inlet 7, an outlet 9 provided on the rear surface of the housing 5 for discharging the air flowing in from the inlet 7 to the outside of the housing 5, a space dividing plate 13 for dividing the interior of the housing 5 into a swirling chamber 14 that is connected to the inlet 7 and is located on the inner periphery side including the center of the housing 5, and a separation chamber 15 that is located on the outer periphery side of the swirling chamber 14, a through hole 16 provided in the space dividing plate 13 for connecting the separation chamber 15 to the swirling chamber 14, and an exhaust port 12 provided below the separation chamber 15 in the direction of gravity when the central axis 6 of the housing 5 is positioned horizontally, connecting the separation chamber 15 to the outside of the housing 5. In the ventilation hood 1, each of the multiple fixed blades 8 has a downstream end 83 and an upstream end 85, and in the cross-sectional shape of the fixed blade 8 in a plane normal to the central axis 6 of the swirl chamber 14, the fixed blade 8 has a linear portion 81 of a predetermined thickness arranged at a predetermined angle (angle D1) with respect to a straight line L1 connecting the central axis 6 and the midpoint of the downstream end 83, and a curved portion 82 extending upstream from the linear portion 81, the upstream end 85 of which is curved toward the outer surface S1 of the fixed blade 8 more than the linear portion 81. The multiple fixed blades 8 are arranged at predetermined intervals (equidistantly) along the circumference of a cylinder (cylindrical surface A1) centered on the central axis 6 of the swirl chamber 14 on the back side of the swirl chamber 14.

With this configuration, when the air (airflow 30) flowing into the housing 5 from outside through the inlet 7 is deflected by the fixed blades 8, it is deflected gradually along the curved portion 82 of the fixed blades 8 to the straight portion 81, suppressing separation of the air flow (airflow 31b) on the inner surface S2 side of the fixed blades 8. This reduces pressure loss caused by separation of the air flow (airflow 31b). In other words, it is possible to provide a ventilation hood 1 that can reduce pressure loss when generating a swirling airflow.

(2) In the ventilation hood 1, the curved portion 82 has a predetermined curvature rate, and is curved so that the tangent line L4 on the inner surface S2 side of the fixed blade 8 at the upstream end 85 is parallel to the straight line L2 connecting the central axis 6 and the midpoint of the upstream end 85. As a result, in a plane normal to the central axis 6 of the swirl chamber 14, the air (airflow 30) sucked from the space outside the housing 5 toward the central axis 6 flows along the curved portion 82 at the upstream end 85 of the fixed blade 8, suppressing separation of the air flow (airflow 31b) on the inner surface S2 of the fixed blade 8, thereby reliably reducing pressure loss.

(3) In the vent hood 1, the curved portion 82 of the cross-sectional shape of the fixed blade 8 is configured to have a shorter length between the upstream side and the downstream side than the straight portion 81. In other words, the distance between the midpoint of the upstream end 85 and the midpoint of the end 84 is configured to be smaller than the distance between the midpoint of the end 84 and the midpoint of the downstream end 83. As a result, the longer the straight portion 81 is, the easier it is for the fixed blade 8 to deflect the air, making it easier to generate a more swirling airflow. On the other hand, the shorter the length between the upstream end 85 and the downstream end 83 of the fixed blade 8, the smaller the friction with the air. Therefore, when generating a swirling airflow (airflow 32) for separating foreign matter, pressure loss can be more reliably reduced.

(Embodiment 2)
Next, the fixed blades 8a constituting the ventilation port hood 1a according to the second embodiment of the present invention will be described with reference to Fig. 7. Fig. 7(a) is a front cross-sectional view of the fixed blades 8a constituting the ventilation port hood 1a according to the second embodiment of the present invention, and Fig. 7(b) is a front cross-sectional view showing the air flow around the fixed blades 8a constituting the ventilation port hood 1a.

The fixed blades 8a constituting the ventilation hood 1a according to the second embodiment differ from those of the first embodiment in that the linear portion 81a of the fixed blades 8a has a thickness T1 at the downstream end 83a that is thinner than the thickness T2 at the upstream end 84a. The rest of the configuration of the ventilation hood 1a is the same as that of the ventilation hood 1 according to the first embodiment. Below, the contents already explained in the first embodiment will not be explained again as appropriate, and the differences from the first embodiment will be mainly explained. Note that the straight lines L1 to L3 and the tangent line L4 in FIG. 7 are set under the conditions specified in the first embodiment.

As shown in FIG. 7(a), the fixed blade 8a constituting the ventilation hood 1a according to the second embodiment has an outer surface S1a facing outward (opposite the central axis 6) and an inner surface S2a facing inward (toward the central axis 6). The fixed blade 8a also includes a straight-line portion 81a that is thinner on the downstream side than on the upstream side, and a curved portion 82a that extends from the upstream side of the straight-line portion 81a and curves toward the outer surface S1a.

More specifically, the fixed blade 8a has a downstream end 83a and an upstream end 85a, and, like the fixed blade 8, is configured with a straight-line portion 81a that is inclined at a predetermined angle (angle D1 in FIG. 5) with respect to the straight line L1, and a curved portion 82a that extends upstream from the straight-line portion 81a, with the end 85a curved toward the outer surface S1a of the fixed blade 8a more than the straight-line portion 81a.

The linear portion 81a is rectangular with a thickness T1 at the downstream end 83a and a thickness T2 at the upstream end 84a. In other words, the linear portion 81a becomes gradually thinner from the upstream side (thickness T2) to the downstream side (thickness T1) of the linear portion 81a. More specifically, the linear portion 81a is formed so that its thickness becomes thinner from the upstream side to the downstream side by cutting the material on the inner surface S2 side compared to the linear portion 81 of the fixed blade 8.

The curved portion 82a is an arc shape that connects the downstream end 84a and the upstream end 85a with a predetermined curvature, and has the same shape as the curved portion 82 of the fixed blade 8.

The length of the curved portion 82a is also configured to be shorter than the straight portion 81a, just like the fixed blade 8.

7(b), in the ventilation hood 1a, the airflow 50 flowing in from the inlet 7 flows radially toward the central axis 6, similar to the airflow 30 in the ventilation hood 1. A part of the airflow 50, the airflow 51a, flows along the outer surface S1a of the fixed blade 8a and is deflected in a direction parallel to the straight line L3. Meanwhile, another part of the airflow 50, the airflow 51b, passes through the inner surface S2a side from the upstream end 85a of the fixed blade 8a. That is, the airflow 51b flows into the inner surface S2a side along the tangent line L4. At this time, the area between the airflow 51b and the inner surface S2a is under negative pressure relative to the surroundings, so the airflow 51b flows along the inner surface S2a and is deflected in a direction along the inner surface S2a on the inner surface S2a side (a direction further deflected than the direction along the straight line L3). Then, downstream of the fixed blades 8a, the airflow 51a and the airflow 51b merge. At this time, the turbulence of the airflow caused by the merging of the airflow 51a and the airflow 51b is suppressed. The airflow then flows into the swirling chamber 14 as the airflow 52, and is deflected by the multiple fixed blades 8a to generate a swirling airflow as the airflow 52.

As described above, the fixed blades 8a constituting the ventilation hood 1a according to the second embodiment provide the following advantages.

(4) In the ventilation hood 1a, the predetermined thickness of the linear portion 81a is configured to become thinner from the upstream side (thickness T2) of the linear portion 81a toward the downstream side (thickness T1). As a result, at the downstream end 83a of the fixed blade 8a, the space between the airflow 51a flowing through the downstream end 83a on the outer surface S1 side of the fixed blade 8a and the airflow 51b flowing through the downstream end 83a on the inner surface S2 side of the fixed blade 8a becomes smaller, and turbulence caused by the airflows intersecting at the downstream end 83a of the fixed blade 8a is suppressed, so that the pressure loss when generating a swirling airflow can be further reduced.

In other words, the airflow 51b that flows along the inner surface S2a of the fixed blade 8a flows at a greater inclination with respect to the straight line L1 passing through the central axis 6 than the airflow 31a. In addition, because the downstream end 83a is thinner, turbulence of the airflow caused by the merging of the airflows 51a and 51b is also suppressed. Therefore, the pressure loss caused by the fixed blade 8a can be further suppressed while maintaining the swirling airflow.

Although the present invention has been described above based on the embodiments, the present invention is in no way limited to the above embodiments, and it can be easily imagined that various improvements and modifications are possible within the scope of the spirit of the present invention. For example, the numerical values given in the above embodiments are merely examples, and it is of course possible to adopt other numerical values.

The cyclone separation device of the present invention can reduce the pressure loss when generating a swirling air current, and therefore the power required for the blower can be reduced, making it effective for separating foreign matter in the air supplied to homes where energy conservation and quiet operation are required, and is useful, for example, as a ventilation hood attached to an air intake on the exterior wall of a home.

REFERENCE SIGNS LIST 1 Ventilation hood 1a Ventilation hood 2 Outlet pipe 3 Cover 4 Base plate 5 Housing 6 Central axis 7 Inlet 8 Fixed blade 8a Fixed blade 8x Fixed blade 9 Outlet 10 Discharge promotion surface 11 Discharge section 12 Discharge port 13 Space dividing plate 14 Swirling chamber 15 Separation chamber 16 Through hole 17 Inner tube 18 Inner tube end surface 19 Square separator 20 Opening 30 Air flow 31a Air flow 31b Air flow 32 Air flow 40 Air flow 41a Air flow 41b Air flow 42 Air flow 50 Air flow 51a Air flow 51b Air flow 52 Air flow 81 Straight-lined portion 81a Straight-lined portion 82 Curved portion 82a Curved portion 83 End 83a End 84 End 84a End 85 End 85a End 85x End L1 Straight line L2 Straight line L3 Straight line L4 Tangent line S1 Outer surface S1a Outer surface S2 Inner surface S2a Inner surface S3 Outer surface S4 Inner surface D1 Angle A1 Cylindrical surface A2 Cylindrical surface SA1 Negative pressure region T1 Thickness T2 Thickness 101 Fixed vane 102 Inlet 103 Swirling chamber 104 Separation chamber

Claims (4)

An inlet for introducing air into the housing;
a plurality of fixed blades that generate a swirling air current within the housing by the air flowing in from the inlet;
an air outlet provided on a rear surface of the housing and configured to allow the air that has flowed in through the air inlet to flow out of the housing;
A space dividing plate that divides the inside of the housing into a swirling chamber that is in communication with the inlet and is located on the inner periphery side including the center of the housing, and a separation chamber that is located on the outer periphery side of the swirling chamber;
a through hole provided in the space dividing plate, the through hole communicating the separation chamber with the swirl chamber;
an outlet provided at a lower position in the separation chamber in a gravity direction with a central axis of the housing being horizontally disposed, the outlet communicating the separation chamber with the outside of the housing;
Equipped with
Each of the multiple fixed blades has a downstream end and an upstream end, and in a cross-sectional shape of the fixed blade taken on a plane normal to the central axis of the swirl chamber, the cross-sectional shape of the fixed blade has a linear portion of a predetermined thickness arranged at a predetermined angle with respect to a straight line connecting the central axis and a midpoint of the downstream end, and a curved portion extending upstream from the linear portion, the upstream end being curved toward the outer surface of the fixed blade more than the linear portion,
A cyclone separation device, wherein the fixed vanes are arranged at a predetermined interval along the circumference of a cylinder centered on the central axis of the swirl chamber on the back side of the swirl chamber. The cyclone separation device according to claim 1, wherein the curved portion has a predetermined curvature rate and is curved so that a tangent line on the inner surface of the fixed blade at the upstream end is parallel to a straight line connecting the central axis and the midpoint of the upstream end. The cyclone separation device according to claim 1 or 2, wherein in the cross-sectional shape of the fixed blade, the curved portion has a shorter length between the upstream side and the downstream side than the straight portion. The cyclone separator according to claim 1 or 2, wherein the predetermined thickness of the linear portion becomes thinner from the upstream side to the downstream side of the linear portion.

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