JP2017040419A - Local ventilator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a local ventilator of which small-sized formation can be attained and which can positively generated a helical sucked circulation flow even if it is made small.SOLUTION: A local ventilator 1 has an outer casing 2 showing a cylindrical shape as seen in a plan view to which both a discharging duct and an air supply duct are connected; an inner casing 3 arranged below an inner part of the outer casing 2, forming a cylindrical shape as seen in a plan view to form an annular air supplying flow passage space 9 in an entire circumferential direction between itself and the outer casing 1. An annular space around a discharging duct connection pipe in the outer casing 2 is applied as an air supply chamber 11, and many wind direction plates 10 are arranged side by side along a slant direction at regular intervals in a circumferential direction over the entire circumference in the annular air supplying flow passage space 9, and thereby a slant flow passage 12 having a rectangular shape in a cross section is formed, these parallel formed slant flow passages 12 are closed for every other space, and a circular pipe member 14 is arranged to be opened to an indoor side in at least an extremity end of the slant flow passage 12 not closed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a local ventilation device for effectively performing local ventilation by artificially generating a spiral suction swirl flow.

  Conventionally, a local ventilation device for locally ventilating air of a specific source such as heat generated by cooking and heating, contaminated air, cigarette smoke, and the like is known. In recent years, some local ventilation devices artificially generate tornadoes and exhaust effectively. Mechanically, a centrifugal force is generated by the swirling airflow on the air supply side, and at the same time, a negative suction core is generated in the center, thereby forming a negative pressure core that is elongated in the suction direction. A tornado is artificially generated in the suction direction while the swirling airflow in a range where the centrifugal force is balanced and converging as a vortex.

  Specifically, as this type of ventilator, for example, in Patent Document 1 below, an air supply chamber into which the inflow air from the air supply duct is introduced in a swirling direction, and a concentrically provided inside the air supply chamber, An exhaust chamber that discharges air through an exhaust duct, and a reflux type that is formed between the exhaust chamber and the air supply chamber and has a long flow path length that allows air introduced from the air supply duct to flow in a swirling state. A ventilation path, a rectifying plate provided in the reflux-type ventilation path for rectifying the air flow flowing in the swirl state, and provided at a lower end side opening surface of the air supply chamber, and swirling direction via the swirl flow generating stator Ventilation provided with an air outlet through which air is blown out, and an air inlet provided in the lower end side opening surface of the exhaust chamber and sucking air in a predetermined local area in a swirling vortex state in the exhaust chamber Location is disclosed.

  Further, in the following Patent Document 2, the air in the ventilation area is provided from the center side air suction port of the apparatus main body and is exhausted to the outside while the air introduced from the outside is provided in the apparatus main body. A ventilator that covers the outer periphery of the ventilation region from the outer peripheral side air outlet and blows out in the form of an air curtain, wherein the air blown out from the outer peripheral side air outlet of the device main body is changed from the upper side to the lower side. The spiral turning airflow that gradually descends while gradually increasing the turning radius is formed, and the air sucked from the air suction port at the center of the apparatus body is gradually increased from the lower side to the upper side correspondingly. A ventilation device is disclosed which has a spiral spiral airflow that shrinks.

Japanese Patent No. 3327247 JP 2001-317785 A

  In medical facilities such as hospitals and nursing care facilities, there are an increasing number of cases where local ventilators are installed so that odors do not spread during procedures such as changing diapers of patients. In many cases, each bed is embedded in the ceiling. Therefore, downsizing of the apparatus is required.

  However, in the case of the ventilator according to Patent Document 1 and Patent Document 2, as described in the same document, it is installed above a heating cooker in a general household kitchen or a commercial kitchen, It is installed at a contaminated dust generation location, and the size of the device itself tends to increase.

  Although it has been proved by experiments of the present inventors that it is easy to effectively generate a spiral suction swirl flow when the local ventilation device is large, the spiral suction swirl flow is reduced as the device is downsized. It has been found that it is difficult to generate.

  Specifically, the ventilator described in Patent Document 1 is provided with a large number of swirl flow generating stators (slanting wind direction plates) that give swirl direction vectors to the air flow inside the chamber. It has been found that when the apparatus is downsized, the airflows from the air outlets interfere with each other and cannot effectively generate a spiral suction swirl flow. Further, in the case of the ventilator described in Patent Document 2, it has a predetermined passage length and is continuously opened in the entire circumferential direction, and the opening diameter increases from the upper side to the lower side. It is formed obliquely at a predetermined inclination angle. A large number of swirling flow generating stators (swirling flow generating means) each having a predetermined inclination angle (radial angle) downward in the spiral direction are maintained at predetermined intervals in the entire circumferential direction. Although a side-by-side structure is adopted (see paragraph [0024]), in this case as well, when the device is downsized, the airflow from the air outlets interfere with each other and effectively spiral. It has been found that a suction swirl cannot be generated.

  Therefore, the main problem of the present invention is to provide a local ventilation device that can reduce the size of the device and can reliably generate a spiral suction swirl flow even when the device is downsized. There is.

In order to solve the above-mentioned problem, the present invention according to claim 1 is provided with an air suction port for exhausting indoor air to the outside through an exhaust duct at the center of the lower surface of the apparatus body, and concentric circles on the outer peripheral side of the air suction port. In the local ventilator provided with an air outlet that blows out the air supplied through the air supply duct in an obliquely downward direction in the same circumferential direction,
The local ventilator is connected to the exhaust duct and the air supply duct, and has an outer casing having a cylindrical shape in a plan view in which the air suction port and the air outlet are provided on a lower surface, and an inner part of the outer casing. An annular air supply passage space is formed in the entire circumferential direction over a predetermined height range between the outer casing and the outer casing, and a cylindrical shape in plan view that defines an exhaust passage. An inner casing, and an exhaust duct connecting pipe that connects the central portion of the upper surface of the inner casing and the exhaust duct, an annular space around the exhaust duct connecting pipe in the outer casing is an air supply chamber,
In the annular air supply channel space, a large number of wind direction plates along the inclined direction at predetermined intervals in the circumferential direction are arranged in parallel in the circumferential direction, thereby forming oblique channels with rectangular sections in parallel. A local ventilator characterized in that every other oblique flow path formed in parallel is closed, and a circular tube is disposed with an opening facing the room at least at the tip of the oblique flow path that is not closed. Provided.

  In the first aspect of the present invention, the local ventilation device according to the present invention has a cylindrical shape in a plan view in which an exhaust duct and an air supply duct are connected and the lower surface is provided with the air inlet and the air outlet. An annular air supply passage space is formed in the entire circumferential direction over a predetermined height range between the outer casing and the outer casing. An inner casing having a cylindrical shape in plan view that defines a flow path; and an exhaust duct connecting pipe that connects a central portion of the upper surface of the inner casing and an exhaust duct, and the exhaust duct connecting pipe in the outer casing The surrounding annular space serves as an air supply chamber.

  Then, in the annular air supply channel space, a large number of wind direction plates along the inclined direction are arranged in parallel in the circumferential direction over the entire circumference, whereby oblique channels having a rectangular cross section are formed in parallel. Each of these oblique flow paths is closed, and a circular pipe is disposed with an opening facing the room at least at the front end of the unobstructed oblique flow path.

  In the annular airflow passage space, a structure in which oblique flow passages having a rectangular cross section are formed in parallel by arranging a large number of wind direction plates along the inclined direction at predetermined intervals in the circumferential direction over the entire circumference. Is a blowout flow path structure similar to that of Patent Document 2, but in such a blowout flow path structure, the blown air from adjacent blowout ports slightly interferes and the swirl flow due to the supply air diffuses. Therefore, even if the odor source has not reached the odor source, or the swirl flow due to the supply air reaches the odor source, the vortex flow of the exhaust gas tends to diffuse due to the influence of the swirl flow of the supply air. It was discovered.

  Therefore, in the present invention, every other oblique flow path formed in parallel is closed, and a circular pipe is disposed with an opening facing the room at least at the tip of the oblique flow path that is not closed. By blocking every other oblique flow path formed in parallel, it is possible to prevent the air blown from adjacent blowout ports from interfering with each other and prevent the swirling flow of the supply air from diffusing. . Further, when the cross-sectional shape of the air outlet remains rectangular, the viscosity coefficient is not uniform in the circumferential direction of the flow path, so that air blown out from the air outlet tends to become resistance at the four corners and increase in diffusion. . On the other hand, when the cross-sectional shape of the air outlet is a circular flow path, the viscosity coefficient is uniform in the circumferential direction, so that diffusion of air ejected from the air outlet is suppressed. In addition, the effect of the structure employ | adopted by the said invention is explained in full detail in the below-mentioned experiment example.

  As a second aspect of the present invention, in the air supply chamber, a donut-shaped first rectifying plate that protrudes outward with the outer surface of the exhaust duct connecting pipe as a base end is disposed on the upper stage side. The local ventilator according to claim 1, wherein a donut-shaped second rectifying plate that protrudes inward with the inner surface of the outer casing as a base end is disposed at a lower position.

  In the invention according to the second aspect, the rectifying plate is arranged in two upper and lower stages. As a result, the swirl flow in the air supply chamber can be stabilized, the air supply air speed can be equalized, and the exhaust efficiency can be improved.

  According to a third aspect of the present invention, there is provided the local ventilator according to any one of the first and second aspects, wherein the outer casing has a diameter of 300 to 600 mm.

  In the invention according to the third aspect, the outer diameter of the outer casing is defined. The present invention is particularly preferably applied to a miniaturized local ventilation device, but can be similarly applied to a conventional medium-sized device or a large-sized device.

  According to a fourth aspect of the present invention, the annular air supply channel space has a height direction dimension of 150 to 250 mm and a width direction dimension of 20 to 50 mm. A ventilation device is provided.

  In the invention described in claim 4, the dimensions of the annular air supply passage space are defined, and even if the apparatus is downsized by setting the numerical value range, the spiral suction swirl It is possible to generate a flow reliably.

  As a fifth aspect of the present invention, there is provided the local ventilator according to any one of the first to fourth aspects, wherein the wind direction plate has an inclination angle of 35 to 55 ° and a horizontal interval of 35 to 55 mm. The

  In the invention according to the fifth aspect, the arrangement of the wind direction plates is defined, so that even when the apparatus is downsized, it is possible to reliably generate a spiral suction swirl flow. .

  As described above in detail, according to the present invention, a local ventilation device capable of reliably generating a spiral suction swirl flow even when the device can be downsized and the device is downsized. Can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is an external view of the room | chamber interior which has arrange | positioned the local ventilation apparatus 1 which concerns on this invention. The local ventilation apparatus 1 is shown, (A) is a plan view and (B) is a side view. It is sectional drawing of the local ventilation apparatus. It is the IV-IV line arrow directional view of FIG. It is the VV line arrow directional view (bottom view) of FIG. It is an inner casing external view which shows the structure of the diagonal flow path 12 part of the flow path space for air supply. The laboratory for an exhaust state verification experiment is shown, (A) is a plan view, (B) is a front view, and (C) is a side view. It is a basic structure figure of the local ventilation apparatus 20 used in an exhaust state verification experiment. It is a side view of the local ventilation apparatus which shows a test body (group I). It is a blower outlet state figure which shows a test body (case 1 of group II). It is a blower outlet state figure which shows a test body (Case 2 of group II). The test body (Case 3 of group II) is shown, (A) is a side view, and (B) is a bottom view. It is a side view which shows a test body (group III-V). It is a side view which shows the test body which concerns on the combination of the improvement plan by which the effect was seen.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  For example, as shown in FIG. 1, a local ventilation device 1 according to the present invention is provided with a local ventilation device 1 on a ceiling surface above each bed in a medical facility or a care facility such as a hospital, and a patient on the bed. While performing treatment such as changing the diaper, the swirl flow N is blown out from the local ventilation device 1 corresponding to the bed, and at the same time, the indoor air is sucked into the space below the local ventilation device 1 to generate the vortex T toward the local ventilation device 1. It is designed to provide individual local ventilation so that odors such as excreta are not diffused into the room. In addition, this local ventilation apparatus 1 can be similarly used also for the ventilation | gas_flowing of the heat | fever which generate | occur | produces at the time of use of the cooking heater used conventionally, and the ventilation of polluted air, and smoke smoke.

  As shown in FIG. 2, the local ventilation device 1 includes an air suction port 8 for exhausting indoor air to the outside through an exhaust duct 6 at the center of the lower surface of the device body, and an outer peripheral side of the air suction port 8. The air outlet 7 which blows off the air supplied concentrically through the air supply duct 5 in an obliquely downward direction in the same circumferential direction.

  Specifically, the local ventilation device 1 has a cylindrical shape in plan view in which the exhaust duct 6 and the air supply duct 5 are connected and the air suction port 8 and the air outlet 7 are provided on the lower surface. An annular air supply passage space 9 is formed between the outer casing 2 and the lower side of the outer casing 2 and has a predetermined height range between the outer casing 2 and the outer casing 2. The inner casing 3 having a cylindrical shape in plan view defining the exhaust flow path, and the exhaust duct connecting pipe 4 connecting the central portion of the upper surface of the inner casing 3 and the exhaust duct 6. An annular space around the exhaust duct connecting pipe 4 is an air supply chamber 11.

  In the annular air supply passage space 9, as shown in detail in FIG. 3, there are a large number of wind direction plates 10, 10,... Along the inclined direction at predetermined intervals in the circumferential direction over the entire circumference. As a result of the parallel arrangement, the oblique channels 12, 12,... Having a rectangular cross section are formed in parallel, and the oblique channels 12, 12,. , 12... Are provided with circular tubes 14 with an opening facing the room at least at the tip.

  This will be described in more detail below.

  The outer casing 2 is a box having a cylindrical lower surface opened in a plan view in which the air suction port 8 and the air outlet 7 are provided on the lower surface, and an air supply duct 5 and an exhaust duct on the upper side surface. 6 are connected to each other. As shown in FIG. 2 (A), the air supply duct 5 moves outward from the center position so that the air supplied into the air supply chamber 11 turns into a swirl flow around the exhaust duct connection pipe 4. It is connected to an eccentric position. The exhaust duct 6 is connected to a position orthogonal to the air supply duct 2 and toward the center. The outer casing 2 has a diameter of 300 to 600 mm, preferably 300 to 400 mm.

  The inner casing 3 is a box that is concentrically disposed on the lower side of the outer casing 2 and has a cylindrical bottom surface in plan view, and has a predetermined height between the inner casing 3 and the outer casing 2. An annular air supply channel space 9 is formed over the entire range and along the entire circumferential direction. A height direction dimension H of the annular air supply passage space 9 is 150 to 250 mm, preferably 180 to 220 mm, and a width direction dimension B is 20 to 50 mm, preferably 20 to 30 mm. In addition, since the height dimension of the inner casing 3 is the same as the dimension H in the height direction of the annular airflow passage space 9, it is set to 150 to 250 mm, preferably 180 to 220 mm. An exhaust duct connection pipe 4 for connecting the central portion of the upper surface of the inner casing 3 and the exhaust duct 6 is provided. The exhaust duct connection pipe 4 is provided on the upper side of the inner casing 3 and around the exhaust duct connection pipe 4 in the outer casing 1. An annular space serves as an air supply chamber 11. A louver is provided on the lower surface of the inner casing 3 (not shown), and an air suction port 8 is formed.

  In the annular air supply passage space 9, as shown in detail in FIGS. 3 to 5, the wind direction plates 10, 10 along the inclined direction at a predetermined interval P in the circumferential direction over the entire circumference. Are arranged in parallel to form the oblique flow paths 12, 12... Having a rectangular cross section. A front end opening of the oblique flow path 12 constitutes the air outlet 7.

  The wind direction plate 10 is fixed so as to protrude outward with the outer surface of the inner casing 3 as a base end, but may be fixed so as to protrude inward with the inner surface of the outer casing 2 as a base end. The wind direction plate 10 is disposed with an inclination angle θ of 35 to 55 °, preferably 40 to 50 °, and a horizontal interval P of 35 to 55 mm, preferably 40 to 50 mm.

  And in this local ventilator 1, while closing the diagonal flow path 12,12 ... formed in parallel every other with the closing board 13, and at least the front-end | tip part of the diagonal flow path 12,12 ... not closed, A circular tube 14 is disposed with the opening facing the room. In the illustrated example, a blocking plate 13 is fixed to the front end portion of the oblique channel 12 (exit of the oblique channel) by welding or the like to close the oblique channel. It may be arranged at the entrance to or in the middle. In addition, it is preferable that the circular pipe material 14 is independently arranged with an outer diameter dimension inscribed in the oblique flow path 12 having a rectangular cross section in a 1: 1 relationship with the oblique flow path 12 having a rectangular cross section. The arrangement position is relatively short (10 to 30% length) with respect to the flow path length of the oblique flow path 12 and is arranged at the tip (exit part) so that the opening faces the room. Is good. Further, when the circular pipe member 14 is installed in an inscribed state in the oblique channel 12 having the rectangular cross section, a slight gap is formed at the four corners. However, the gap may be closed or may not be closed.

  On the other hand, in the air supply chamber 11, as shown in FIGS. 2 (B) and 3, a donut-shaped second protrusion projecting outward from the outer surface of the exhaust duct connection pipe 4 at the upper stage side. It is preferable to dispose the first rectifying plate 15 and the donut-shaped second rectifying plate 16 protruding inward with the inner surface of the outer casing 2 as the base end at the lower position. By arranging the rectifying plates 15 and 16 in two upper and lower stages, the swirl flow in the air supply chamber 11 can be stabilized, the air supply air speed can be equalized, and the exhaust efficiency can be improved. Can be improved.

  Next, an exhaust state verification experiment conducted to develop the local ventilation device according to the present invention will be described in detail.

(1) Experimental environmental conditions As shown in FIG. 7, assuming a hospital room, the experimental space is W4000mm × D6000mm × H2700mm, the local ventilation device 20 is installed on the ceiling surface in the center, and the bed 21 is placed below it. installed. The size of the bed 21 was 1800 mm × 900 mm and the height was 500 mm. In order to visualize the odor, a smoke generator 22 (device name: smoked scene [MODEL: Z1000II]) was installed below the bed 21 to generate smoke from the center of the bed 21.

  When the basic structure of the local ventilation device 20 is compared with the structure shown in FIG. 8, that is, the local ventilation device 1 according to the present invention shown in FIGS. 2 to 6, the first rectifying plate 15 and the second rectifying plate 16 are provided. All of the channels are effective without being obstructed by the oblique channels 12, and the circular tube 14 is omitted. The dimensions of the outer casing 2 are φ375 mm, the diameter of the air supply duct 5 and the exhaust duct 6 is φ175 mm, the annular airflow passage space 9 is 200 mm in height and 25 mm in width, No. 10 has an inclination angle of 45 ° and a horizontal interval of 45 mm.

表１に示されるように、条件No.１〜６については、煙が真上に上昇せずに拡散した。これは、給気の回転エネルギーがトルネード現象を発生させるベッドまで届いていないため煙が淀んでしまうことに原因していると思われる。また、条件No.７〜９については、煙が大きな回転で上昇するが、ほとんど拡散した。これは、給気の回転エネルギーがベッド上までほぼ届いているが、給気の吹出風が排気の範囲にも影響を及ぼしているため、上昇した煙を拡散させてしまうためと思われる。 (2) Exhaust Situation with Basic Structure Local Ventilation Device 20 First, with the local ventilation device 20 with the basic structure shown in FIG. The results are shown in Table 1 below.

As shown in Table 1, with respect to the conditions No. 1 to 6, the smoke diffused without rising right above. This seems to be due to the fact that the rotational energy of the supply air does not reach the bed where the tornado phenomenon occurs, so that smoke smokes. Moreover, about conditions No. 7-9, although smoke rose by big rotation, it spread | diffused almost. This is probably because the rotational energy of the supply air has almost reached the bed, but the blowout air of the supply air also affects the exhaust range, so that the rising smoke is diffused.

  As described above, in the local ventilation device 20 having the basic structure shown in FIG. 8, ideal exhaust cannot be achieved even if the supply / exhaust air volume is variously changed.

(3) Improvement to Basic Structure Therefore, various improvement proposals were tried for the local ventilation device 20 having the basic structure shown in FIG. 8, and the exhaust performance was verified.

グループＩケース(1)の整流板を上下二段で二重にで配置するというのは、図９に示されるように、基本構造の局所換気装置２０に対して本願発明のように上下二段で整流板を取り付けた試験体である。グループＩケース(2)は整流板をパンチング板とした場合の試験体である。グループIIケース(1)は図１０に示されるように、吹出口７の内周側半分を塞いた試験体である。グループIIケース(2)は、図１１に示されるように、斜め流路１２を一つ置きに塞いだ試験体であり、グループIIケース(3)は図１２に示されるように、斜め流路を一つ置きに塞ぐとともに、塞がれていない斜め流路の先端部に室内に開口を臨ませてパイプを配置した試験体である。グループIII〜Ｖについては、纏めて図１３に示す。グループIIIケース(1)は空気吹出口７の内側に給気案内板を取り付けた試験体であり、グループIIIケース(2)は空気吹出口７の外側に給気案内板を取り付けた試験体であり、グループIVは排気の補助のために排気口内部にプロペラファンを取り付けた試験体であり、グループＶは排気風速向上のために排気口に小口径管を取り付けた試験体である。 The improvement plan was divided into groups I to V. Group I is an improvement plan related to equalization of the supply air speed, Group II is an improvement plan related to the blowout structure for stabilizing the supply air wind, and Group III is an improvement plan related to installation of a guide plate for stabilizing the supply air wind. Group IV is an improvement plan related to the installation of an exhaust propeller fan for assisting tornado ventilation, and Group V is an improvement plan related to the installation of a small exhaust pipe for increasing the exhaust air speed. The specific contents of these improvements are shown in Table 2 below.

The dual arrangement of the rectifying plates of the group I case (1) in two upper and lower stages, as shown in FIG. It is a test body with a rectifying plate attached. Group I case (2) is a test specimen in which the current plate is a punching plate. The group II case (1) is a test body in which the inner peripheral half of the air outlet 7 is closed as shown in FIG. As shown in FIG. 11, the group II case (2) is a test body in which every other oblique channel 12 is closed, and the group II case (3) is shown in FIG. Is a test body in which every other pipe is closed and a pipe is arranged with the opening facing the interior of the tip of the oblique flow path that is not closed. Groups III to V are collectively shown in FIG. Group III case (1) is a test body with an air supply guide plate attached to the inside of the air outlet 7, and Group III case (2) is a test body with an air supply guide plate attached to the outside of the air outlet 7. Yes, Group IV is a test body in which a propeller fan is attached to the inside of the exhaust port for assisting exhaust, and Group V is a test body in which a small-diameter pipe is attached to the exhaust port for improving the exhaust air speed.

以上の結果より、排気性能に効果が見られたのは、グループＩケース(1)、グループIIケース(2)及びケース(3)であった。そこで、これらを組み合わせた図１４に示される局所換気装置によって排気状態の検証を行った。その際の給気風量：３００m³/h、排気風量：５００m³/hとした。トルネード（排気旋回流）は拡散することなく煙が回転しながら上昇して綺麗に排気された。また、トルネードが安定して形成されるようになり排気が安定した。 Table 3 shows the results of exhaust state verification experiments performed on the test specimens of these groups I to V.

From the above results, it was Group I Case (1), Group II Case (2) and Case (3) that had an effect on the exhaust performance. Therefore, the exhaust state was verified by the local ventilation device shown in FIG. The supply air volume at that time was 300 m ³ / h, and the exhaust air volume was 500 m ³ / h. Tornado (exhaust swirl) was exhausted neatly without smoke spreading and rotating while rotating. Also, the tornado was formed stably and the exhaust was stable.

  DESCRIPTION OF SYMBOLS 1 ... Local ventilation apparatus, 2 ... Outer casing, 3 ... Inner casing, 4 ... Exhaust duct connection pipe, 5 ... Air supply duct, 6 ... Exhaust duct, 7 ... Air outlet, 8 ... Air inlet, 9 ... Ring-shaped Air supply channel space, 10 ... Air direction plate, 11 ... Air supply chamber, 12 ... Oblique flow channel, 13 ... Blocking plate, 14 ... Circular pipe, 15 ... First rectifier plate, 16 ... Second rectifier plate

Claims (5)

An air suction port for exhausting room air to the outside through an exhaust duct is provided at the center of the lower surface of the apparatus main body, and the air supplied through the air supply duct concentrically on the outer peripheral side of the air suction port is inclined in the same circulation direction. In a local ventilator with an air outlet that blows out downward,
The local ventilator is connected to the exhaust duct and the air supply duct, and has an outer casing having a cylindrical shape in a plan view in which the air suction port and the air outlet are provided on a lower surface, and an inner part of the outer casing. An annular air supply passage space is formed in the entire circumferential direction over a predetermined height range between the outer casing and the outer casing, and a cylindrical shape in plan view that defines an exhaust passage. An inner casing, and an exhaust duct connecting pipe that connects the central portion of the upper surface of the inner casing and the exhaust duct, an annular space around the exhaust duct connecting pipe in the outer casing is an air supply chamber,
In the annular air supply channel space, a large number of wind direction plates along the inclined direction at predetermined intervals in the circumferential direction are arranged in parallel in the circumferential direction, thereby forming oblique channels with rectangular sections in parallel. A local ventilator characterized in that every other oblique flow path formed in parallel is closed, and a circular pipe is disposed with an opening facing the room at least at the tip of the oblique flow path that is not closed.   In the air supply chamber, a donut-shaped first rectifying plate that protrudes outward from the outer surface of the exhaust duct connecting pipe is disposed on the upper stage side, and the inner surface of the outer casing is based on the lower stage position. The local ventilation device according to claim 1, wherein a donut-shaped second rectifying plate protruding inward as an end is disposed.   The local ventilator according to claim 1, wherein the outer casing has a diameter of 300 to 600 mm.   The local ventilation apparatus according to any one of claims 1 to 3, wherein the annular air supply channel space has a height direction dimension of 150 to 250 mm and a width direction dimension of 20 to 50 mm.   The local ventilation apparatus according to any one of claims 1 to 4, wherein the wind direction plate has an inclination angle of 35 to 55 ° and a horizontal interval of 35 to 55 mm.

Images