JP2013088012A - Local air purification device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a local air purification device having a simple structure.SOLUTION: This local air purification device 1 is provided with a push hood 2 having an airflow aperture surface 23 that discharges a purified uniform airflow. The push hood 2 is disposed in a manner so that the uniform airflow discharged from the airflow aperture surface 23 impinges on an air impingement surface W at the downstream side of the airflow aperture surface 23. The push hood 2 forms an open region between the air impingement surface W and the airflow aperture surface 23 of the push hood 2 by causing the airflow aperture surface 23 to face the air impingement surface W while being separated therefrom. The purified uniform airflow discharged from the airflow aperture surface 23 causes the inside of the open region to have a high level of cleanliness compared to other regions by means of impinging on the air impingement surface W and flowing out of the open region.

Description

  The present invention relates to a local air cleaning device.

  Conventionally, a clean bench is often used as an apparatus for improving the air cleanliness of a local work space. In a general clean bench, only the front surface of the work table is a work opening, and the other surfaces are enclosed to maintain cleanliness. In such a clean bench, a clean air outlet is arranged in the enclosure, and an operator works by putting his hand through the opening for work in front.

  However, since the work opening of the clean bench is narrow, there is a problem in workability when an operator performs assembly work of a precision machine. In addition, when products and manufactured parts are moved as in a production line, measures such as putting the entire line into a clean room have been taken, but this has the problem that the facility becomes large-scale. is there.

  For this reason, the air flow opening surfaces of a pair of push hoods that can blow out a uniform flow of purified air are arranged to face each other, and the air flows from the respective air flow opening surfaces collide with each other. There has been proposed a local air cleaning device that can make a region between the push hoods into a clean air space having a higher cleanliness than other regions (Patent Document 1).

JP 2008-275266 A

  By the way, depending on the type of work and the way the work is carried out, there are cases where it is desired to work using a local air cleaning device having a slightly simpler structure. For this reason, a local air cleaning apparatus having a simpler structure is desired.

  The present invention has been made in view of the above problems, and an object thereof is to provide a local air cleaning device having a simple structure.

In order to achieve the above object, the local air cleaning device of the present invention comprises:
A push hood having an air flow opening surface for blowing a cleaned uniform air flow;
The push hood is arranged so that the purified uniform air flow blown out from the air flow opening surface collides with an air collision surface on the downstream side of the air flow opening surface,
By forming the air flow opening surface of the push hood away from and facing the air collision surface, an open area is formed between the air flow opening surface of the push hood and the air collision surface,
The cleaned uniform air flow blown out from the air flow opening surface collides with the air collision surface and flows out of the open region, thereby comparing the inside of the open region with other regions. It is characterized by high cleanliness.

The push hood is formed by connecting a plurality of push hoods, for example.
The flow rate of the purified uniform air flow blown out from the air flow opening surface is preferably 0.2 to 0.5 m / s.
The width of the air flow opening surface of the push hood is 2 m or more and less than 10 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance that the uniform air flow blown from the air flow opening surface collides with the air collision surface within 4 seconds. preferable.
The width of the air flow opening surface of the push hood is 1 m or more and less than 2 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance that the uniform air flow blown from the air flow opening surface collides with the air collision surface within 3 seconds. preferable.
The width of the air flow opening surface of the push hood is 0.2 m or more and less than 1 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance that the uniform air flow blown from the air flow opening surface collides with the air collision surface within 2 seconds. preferable.

It is preferable that the air collision surface has a bent portion that is bent toward the push hood in the vicinity of a position facing the end of the air flow opening surface of the push hood.
The width of the air flow opening surface of the push hood is 2 m or more and less than 10 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance at which the uniform air flow blown from the air flow opening surface collides with the air collision surface within 6 seconds. preferable.
The width of the air flow opening surface of the push hood is 1 m or more and less than 2 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance at which the uniform air flow blown from the air flow opening surface collides with the air collision surface within 5 seconds. preferable.
The width of the air flow opening surface of the push hood is 0.2 m or more and less than 1 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance that the uniform air flow blown from the air flow opening surface collides with the air collision surface within 3 seconds. preferable.

  According to the present invention, it is possible to provide a local air cleaning device having a simple structure.

It is a figure which shows the local air cleaning apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of a push hood. It is a figure which shows another example of a local air cleaning apparatus. It is a figure for demonstrating the flow of the cleaned uniform airflow. It is a figure for demonstrating the width | variety of an airflow opening surface. It is a figure which shows the local air cleaning apparatus of other embodiment. It is a figure which shows the local air cleaning apparatus of other embodiment. It is a figure which shows the local air cleaning apparatus of other embodiment. FIG. 3 is a diagram illustrating measurement positions in Example 1.

  Hereinafter, the local air cleaning apparatus of this invention is demonstrated with reference to drawings. FIG. 1 is a diagram illustrating an example of a local air cleaning device according to an embodiment of the present invention.

  As shown in FIG. 1, the local air purification apparatus 1 of this invention is equipped with the push hood 2 arrange | positioned so as to oppose air collision surfaces W, such as a wall and a partition.

  The push hood 2 only needs to have a mechanism for blowing out a purified uniform air flow. The push hood 2 that has been used in a push-pull type ventilator has a basic structure and a cleaning filter is provided inside. A structure can be adopted.

  The uniform air flow and the uniform flow mentioned here are synonymous with the uniform flow described in “Factory ventilation” by Taro Hayashi (published in 1982 by the Society for Air Conditioning and Hygiene Engineering). It means the flow of light wind speed that does not occur. However, the present invention is not intended to provide an air blowing device that strictly defines the flow velocity and velocity distribution of air. The uniform air flow preferably has, for example, a variation in velocity distribution with no obstacles within ± 50%, more preferably within ± 30% of the average value.

  FIG. 2 shows the structure of the push hood 2. As shown in FIG. 2, the housing 21 of the push hood 2 is formed in a substantially rectangular parallelepiped shape, and an air flow suction surface 22 is formed on one surface thereof. For example, the air flow suction surface 22 includes a surface in which a plurality of holes are formed on the entire surface of the housing 21. In the air flow suction surface 22, outside air or room air that is ambient air outside the push hood 2 is taken in from this hole. An air blowing surface (air flow opening surface) 23 is formed on the other surface of the housing 21 that faces the air flow suction surface 22. For example, the air flow opening surface 23 includes a surface in which a plurality of holes are formed on the entire surface of the housing 21. On the air flow opening surface 23, a uniform air flow of clean air formed in the push hood 2 is blown out of the push hood 2 from this hole. Although the magnitude | size of the airflow opening surface 23 of the push hood 2 is not specifically limited, For example, it is 1050 mm x 850 mm.

  The push hood 2 is disposed such that the air flow opening surface 23 faces the air collision surface W such as a wall with a distance X apart. Here, the fact that the air flow opening surface 23 faces the air collision surface W is not limited to the state in which the air flow opening surface 23 of the push hood 2 and the air collision surface W face each other. As shown in FIG. 4, the push hood 2 in which the air flow opening surface 23 and the air collision surface W are slightly inclined is also included. The inclination of the air flow opening surface 23 and the air collision surface W of the push hood 2 is preferably within the range of about 30 ° formed by the air flow opening surface 23 and the air collision surface W.

A blower mechanism 24, a high-performance filter 25, and a rectifying mechanism 26 are disposed in the housing 21.
The air blowing mechanism 24 is disposed on the air flow suction surface 22 side in the housing 21. The blower mechanism 24 includes a fan for blowing air. The blower mechanism 24 takes in outside air and room air that are ambient air of the push hood 2 from the airflow suction surface 22 and blows out an airflow from the airflow opening surface 23. The blower mechanism 24 is formed so that the flow velocity of the airflow blown out from the airflow opening surface 23 can be varied by controlling the blowing force of the fan.

  The high performance filter 25 is disposed between the air blowing mechanism 24 and the rectifying mechanism 26. The high-performance filter 25 is composed of a high-performance filter according to the cleaning level such as a HEPA filter (High Efficiency Particulate Air Filter) or a ULPA filter (Ultra Low Penetration Air Filter) for filtering the ambient air taken in. . The high performance filter 25 cleans the ambient air taken in by the blower mechanism 24 to clean air having a desired cleaning level. The clean air cleaned to a desired cleaning level by the high-performance filter 25 is sent to the rectifying mechanism 26 by the blower mechanism 24.

  The rectifying mechanism 26 is disposed between the high performance filter 25 and the air flow opening surface 23. The rectifying mechanism 26 includes an air resistor (not shown), which is formed of a punching plate, a net member, or the like. The rectifying mechanism 26 is blown from the high-performance filter 25 and blown air that is biased in the air flow rate with respect to the entire air flow opening surface 23 is made uniform with no air flow rate bias in the entire air flow opening surface 23. Correct (rectify) the air flow (uniform air flow). The rectified uniform air flow is blown out of the push hood 2 from the entire air flow opening surface 23 by the blower mechanism 24.

  Further, as shown in FIG. 2, the push hood 2 is preferably provided with a pre-filter 27 between the air flow suction surface 22 in the housing 21 and the air blowing mechanism 24. An example of the prefilter 27 is a medium performance filter. By disposing the pre-filter 27 between the air flow suction surface 22 and the air blowing mechanism 24, relatively large dust contained in the ambient air sucked into the housing 21 through the air flow suction surface 22 can be removed. it can. Thus, since dust can be removed in multiple stages according to the size of the dust contained in the ambient air, the performance of the high-performance filter 25 that is likely to be clogged can be maintained for a long period of time.

  In the local air cleaning device 1 configured as described above, the ambient air in the vicinity of the air flow suction surface 22 taken in by the blower mechanism 24 of the push hood 2 is cleaned by the prefilter 27 and the high-performance filter 25 to a desired cleaning level. Cleaned with clean air. Then, the cleaned clean air is rectified into a uniform air flow by the rectifying mechanism 26, and the cleaned uniform air flow is blown out from the entire air flow opening surface 23 to the air collision surface W. The air flow blown out from the air flow opening surface 23 collides with the air collision surface W. As shown in FIG. 4, when the air flow opening surface 23 is directly opposed to the air collision surface W, the uniform air flow exhibits a behavior that changes the flow direction substantially perpendicularly when it collides with the air collision surface W. By flowing in this way, the air flow that collided with the air collision surface W flows out to the outside of the collided surface. As a result, a clean space is obtained in the region from the surface where the airflow collides to the end of the airflow opening surface 23.

  Here, the flow rate of the purified uniform air flow blown out from the air flow opening surface 23 is preferably 0.3 to 0.5 m / s. If you want to reduce the wind speed to ~ 0.3m / s or if the local air cleaning device 1 is contaminated and you want to clean it quickly, increase the wind speed to 0.5 ~ 0.7m / s or select as appropriate. It is also possible to do. When the flow rate is slowed, the rotational speed of the fan of the blower mechanism can be suppressed, so that the noise value and power consumption can be suppressed. Accordingly, the amount of air blown is reduced, so that the amount of dust accumulated on the pre-filter 27 and the high-performance filter 25 can be reduced. On the other hand, in a situation where contamination is generated in an open region formed between the air flow opening surface 23 and the air collision surface W, the flow rate of the uniform air flow is set to about 0.5 m / s. As a result, it is possible to quickly eliminate the contaminants in the open region as compared with the case where the flow velocity of the uniform air flow is set to 0.2 m / s. As described above, it is possible to freely set the flow velocity of the uniform air flow according to the intended use. In addition, if the wind speed of the uniform air flow blown out from the air flow opening surface 23 is increased too much, a vortex portion is generated, causing turbulent flow when the uniform air flow blows out from the air flow opening surface 23, and the air flow opening surface. There is a possibility that contaminants outside the open area may be caught in the open area formed between the air contact surface W and the air collision surface W. For this reason, it is preferable that the wind speed of the uniform air flow blown out from the air flow opening surface 23 is a wind speed that does not cause a vortex.

  In addition, the distance between the air flow opening surface 23 and the air collision surface W is within a distance of 4 times the flow velocity when the width of the air flow opening surface 23 is 2 m or more and less than 10 m (the air flow opening surface 23 is blown out. The distance at which the uniform air flow collides with the air collision surface W within 4 seconds is preferable. In addition, when the width of the air flow opening surface 23 is 1 m or more and less than 2 m, the distance within three times the flow velocity (the uniform air flow blown from the air flow opening surface 23 collides with the air collision surface W within 3 seconds. Within a distance). Further, when the width of the air flow opening surface 23 is 0.2 m or more and less than 1 m, the air collision surface W is within a distance twice the flow velocity (the uniform air flow blown from the air flow opening surface 23 is within 2 seconds. It is preferable to set the distance to collide with. This is because the open area between the air flow opening surface 23 and the air collision surface W can be made highly clean by setting such a distance.

  Here, when the airflow opening surface 23 is circular, the width (L) of the airflow opening surface 23 refers to the diameter of the circle as shown in FIG. In addition, when the air flow opening surface 23 is rectangular, the width (L) of the air flow opening surface 23 is the diameter of the largest inscribed circle, that is, the length of the short side, as shown in FIG. Say. Further, the width (L) of the air flow opening surface 23 is the diameter of the largest inscribed circle as shown in FIGS. 5C to 5G when the air flow opening surface 23 is elliptical or polygonal. Say. Further, the width (L) of the air flow opening surface 23 is the diameter of a circle inscribed at the position where the distance between the facing sides is the shortest, as shown in FIG. Say. Further, the width (L) of the air flow opening surface 23 is inscribed at a position where the distance between the side having the recess and the side facing the side is the shortest as shown in FIG. 5I when the opening surface is concave. The diameter of a circle.

  As described above, according to the local air cleaning device 1 of the present embodiment, the push hood 2 is disposed so as to face the air collision surface W, whereby the air flow opening surface 23, the air collision surface W, and the like. The open area between the two can be higher in cleanliness than the area outside the local air cleaning device 1. As described above, the present invention can provide the local air cleaning device 1 having a simple structure.

  Further, in a general clean room, since the entire room is cleaned, construction work is not easy, but in the local air cleaning device 1 of the present embodiment, the push hood 2 can be easily moved.

  Furthermore, in the open area of the present embodiment, there are no doors for putting in and out workers, parts, and manufacturing equipment necessary for a general clean room, and cleaning in the clean space area by opening these doors. There is no decrease in the degree, and it is possible to go in and out from the open area at any time, or to put in and out the parts. In a general clean room, when the inside of the clean room is contaminated, the contaminated air in the clean room is diluted by the clean air supplied to the clean room, and this is exhausted to gradually clean the inside of the clean room. Therefore, when the inside of the clean room is contaminated, it takes several hours to be cleaned. However, in the present invention, even if the inside of the open area is contaminated, the purified uniform air flow blown out from the air flow opening surface 23 flows so as to push out the contaminated air, so that it is cleaned in a very short time. It is possible.

  In a general clean room, clean air supplied to the clean room is exhausted through an exhaust port provided in the clean room or a slight gap formed between the wall surface and the floor surface of the clean room. This is because in a general clean room, the clearance is positively reduced and the inside of the clean room is set to a positive pressure to prevent the entry of contaminated air from the outside. However, the present invention does not require a wall surface like the clean room, can form an open region, and can clean the formed space. For this reason, it is highly convenient to use this open area as a cleaned area for the entrance and exit as described above.

  In addition, this invention is not restricted to said embodiment, A various deformation | transformation and application are possible. Hereinafter, other embodiments applicable to the present invention will be described.

  In the said embodiment, although this invention was demonstrated to the case where the push hood 2 was comprised from one push hood as an example, the number of push hoods which comprise the push hood 2 may be plural. . For example, as shown in FIG. 6, the push hood 2 may be connected to nine push hoods (3 vertical × 3 horizontal) by a connecting tool. In addition, the push hood 2 may be connected to four (two vertical × two horizontal) push hoods by a connector. When the push hoods are connected as described above, the air flow opening surfaces of the push hoods are in the same direction, and the push hoods are arranged so that the short sides and the long sides are adjacent to each other. At this time, the side surfaces of the push hoods, the upper and lower surfaces or both surfaces of the push hoods are connected in an airtight state, or between the side surfaces, the upper and lower surfaces or both surfaces of the adjacent push hoods. It is preferable to be connected in an airtight state through a sealing material such as packing. Also in these cases, the open area between the air flow opening surface 23 and the air collision surface W can be made higher in cleanliness than the area outside the local air cleaning device 1.

  In the above embodiment, the present invention has been described by taking the case where the air collision surface W has a flat plate shape such as a wall or a partition, but the air collision surface W is not limited to a flat plate shape. For example, the air collision surface W is in the vicinity of the position facing the end of the air flow opening surface 23 of the push hood 2, for example, the end of the air collision surface W, for example, as shown in FIG. It is preferable to have a bent portion W1 that is bent toward the push hood 2 side. Further, the air collision surface W may have a bent portion W1 in which all of the upper portion, the lower portion, and the side portion thereof are bent toward the air flow opening surface 23 side. Further, the bent portion W1 may be rounded (with a rounded shape) so as to have a gentle curved surface. Since the air collision surface W has the bent portion W1 in this way, air from outside the open region (outside the local air cleaning device 1) formed between the air flow opening surface 23 and the air collision surface W is obtained. It becomes easy to prevent inflow. For this reason, the region between the air flow opening surface 23 and the air collision surface W can be made higher in cleanliness than the region outside the local air cleaning device 1, and the local air cleaning device 1 having a simple structure can be obtained. Can be provided.

  In the case of the local air cleaning device 1 having such a bent portion W1, the distance between the air flow opening surface 23 and the air collision surface W is the flow velocity when the width of the air flow opening surface 23 is 2 m or more and less than 10 m. It is preferable to be within a distance of 6 times (a distance at which the uniform air flow blown from the air flow opening surface 23 collides with the air collision surface W within 6 seconds). Further, when the width of the air flow opening surface 23 is 1 m or more and less than 2 m, the distance within 5 times the flow velocity (the uniform air flow blown from the air flow opening surface 23 collides with the air collision surface W within 5 seconds. Within a distance). Further, when the width of the air flow opening surface 23 is 0.2 m or more and less than 1 m, the air collision surface W is within a distance of three times the flow velocity (the uniform air flow blown from the air flow opening surface 23 is within 3 seconds. It is preferable to set the distance to collide with. This is because the open area between the air flow opening surface 23 and the air collision surface W can be made highly clean by setting such a distance.

  The push hood 2 may have a structure in which casters are attached to the bottom surface. In this case, the push hood 2 can be easily moved. In this case, the construction is easy and the movement can be easily performed.

  Moreover, you may arrange several push hoods 2 in parallel toward the wall surface (air collision surface W), as shown to Fig.8 (a). In this case, since a clean space is formed between the push hood 2 and the wall (air collision surface W), it is possible to easily form a clean passage. Furthermore, as shown in FIGS. 8B to 8D, the wall surface (air collision surface W) is formed in an L shape, so that it can be applied even when the passage is in an L shape. Therefore, it is possible to easily form an unusual clean space.

  Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention.

Example 1
Using the local air cleaning device 1 shown in FIG. 1, the cleanliness was measured at the measurement positions 1 to 18 shown in FIG. FIG. 9 is a top view of the local air cleaning device 1. The cleanliness was measured by measuring the number of dust particles (particles / CF) with a particle diameter of 0.3 μm using KC-18, a particle counter manufactured by Lion. The degree of cleanliness was evaluated as high cleanliness when the number was 300 or less. The push hood 2 is a push hood having a width of 600 mm and a length of 600 mm. About the measurement height of the measurement positions 1-18, it was 300 mm which is a position of 1/2 of the height of the push hood 2. The measurement positions 1 to 6 were the center of the width of the push hood 2 and were positioned 200 mm downstream from the air flow opening surface 23 of the push hood 2. However, the measurement position 6 was a position 100 mm downstream of the measurement position 5. The measurement positions 7 to 12 were the same positions as the measurement positions 1 to 6 except that the measurement positions 13 to 18 were 200 mm from the center of the push hood 2 width and the measurement positions 13 to 18 were 250 mm from the center of the push hood 2 width. The distance X between the air flow opening surface 23 of the push hood 2 and the air collision surface W was 1200 mm, and the flow rate of the cleaned uniform air flow was 0.5 m / s. The results are shown in Table 1. In addition, for comparison, the case where the air collision surface W (wall) is not provided (Comparative Example 1) is shown in Table 2, and when the push hood is arranged instead of the wall and the push hood is opposed as in Patent Document 1 (Comparative Example 2) is shown in Table 3. In Comparative Example 2, the measurement positions 6, 12, and 18 are not measured.

Example 1

(Comparative Example 1)

(Comparative Example 2)

  As shown in Table 1, by disposing the push hood 2 so as to face the air collision surface W, the open area between the air flow opening surface 23 and the air collision surface W is defined as a local air cleaning device 1. It was confirmed that the degree of cleanliness can be higher than that in the outside region. For this reason, it was confirmed that the local air cleaning apparatus 1 having a simpler structure can be provided. Further, as shown in Table 1 and Table 3, by disposing the push hood 2 so as to face the air collision surface W, an open area between the air flow opening surface 23 and the air collision surface W is pushed. It was confirmed that the degree of cleanliness can be made higher than the area outside the local air cleaning device 1 like the local air cleaning device 1 of Patent Document 1 in which the hood is opposed. For this reason, it confirmed that the local air cleaning apparatus 1 of a simple structure could be provided. Moreover, as shown in Table 1 and Table 2, by providing the air collision surface W, the open area between the air flow opening surface 23 and the air collision surface W is made larger than the area outside the local air cleaning device 1. It was confirmed that high cleanliness can be achieved.

  The present invention is useful for air cleaning a local work space.

DESCRIPTION OF SYMBOLS 1 Local air purification apparatus 2 Push hood 21 Housing 22 Air flow suction surface 23 Air blowing surface (air flow opening surface)
24 Blower mechanism 25 High-performance filter 26 Rectifier mechanism 27 Prefilter W Air collision surface

Claims (10)

A push hood having an air flow opening surface for blowing a cleaned uniform air flow;
The push hood is arranged so that the purified uniform air flow blown out from the air flow opening surface collides with an air collision surface on the downstream side of the air flow opening surface,
By forming the air flow opening surface of the push hood away from and facing the air collision surface, an open area is formed between the air flow opening surface of the push hood and the air collision surface,
The cleaned uniform air flow blown out from the air flow opening surface collides with the air collision surface and flows out of the open region, thereby comparing the inside of the open region with other regions. A local air cleaning device characterized by high cleanliness.   The local air cleaning device according to claim 1, wherein the push hood is formed by connecting a plurality of push hoods.   The local air cleaning device according to claim 1 or 2, wherein the flow rate of the purified uniform air flow blown out from the air flow opening surface is 0.2 to 0.5 m / s. . The width of the air flow opening surface of the push hood is 2 m or more and less than 10 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance that the uniform air flow blown from the air flow opening surface collides with the air collision surface within 4 seconds. The local air purifier according to any one of claims 1 to 3, wherein the local air cleaner is characterized in that: The width of the air flow opening surface of the push hood is 1 m or more and less than 2 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance that the uniform air flow blown from the air flow opening surface collides with the air collision surface within 3 seconds. The local air purifier according to any one of claims 1 to 3, wherein the local air cleaner is characterized in that: The width of the air flow opening surface of the push hood is 0.2 m or more and less than 1 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance that the uniform air flow blown from the air flow opening surface collides with the air collision surface within 2 seconds. The local air purifier according to any one of claims 1 to 3, wherein the local air cleaner is characterized in that:   The said air collision surface has the bending part bent toward the said push hood side in the vicinity of the position which opposes the edge part of the said air flow opening surface of the said push hood. The local air purifier according to claim 1. The width of the air flow opening surface of the push hood is 2 m or more and less than 10 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance that the uniform air flow blown from the air flow opening surface collides with the air collision surface within 6 seconds. The local air cleaning device according to claim 7, wherein the device is a local air cleaning device. The width of the air flow opening surface of the push hood is 1 m or more and less than 2 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance that the uniform air flow blown from the air flow opening surface collides with the air collision surface within 5 seconds. The local air cleaning device according to claim 7, wherein the device is a local air cleaning device. The width of the air flow opening surface of the push hood is 0.2 m or more and less than 1 m,
The distance between the air flow opening surface of the push hood and the air collision surface is a distance that the uniform air flow blown from the air flow opening surface collides with the air collision surface within 3 seconds. The local air cleaning device according to claim 7, wherein the device is a local air cleaning device.