A method for forming a zone surrounded by an air-stream

Abstract: The present invention relates to a zone-forming apparatus. This apparatus is adapted to direct a jet-stream (A) in a radial direction by means of a guide member (1), the jet-stream being emitted from jet-stream generating means (2) which is arranged above the apparatus, and an air curtain thus formed is utilized to define a working space.

Description: The present invention relates to a method which is suitable for forming in the air a zone surrounded by an air-stream. A radiative dust removal apparatus as shown in Fig. 9 is known from the Japanese Utility Model Application No. SHO62-111700 Publication Official Gazette. In this radiative dust removal apparatus, an air which has been purified in a treatment device 01 is forced by an air fan 02 to flow through a path 06 defined between the outer tube 04 and the inner tube 05 of the dual duct 03 and is supplied into the central portion of the canopy-like hood 07. The air is raidially diffused while it flows through an internal fluid path 013 and is blown-out downwardly through an air blown-out port 08 in an outer circumference and thereby forming an air curtain 09. A local working space 011 is thus formed in a chamber 010, which is surrounded by the air curtain 09 and a contaminated air in he working space 011 is withdrawn through an air receiving inlet 012 which opens downwardly to the central undersurface of the canopy-like hood 07 into the inner tube 05 for transfer into the treatment apparatus in which the air is subsequently separated into contaminated solids and a purified air. In the above-described traditional apparatus, the air is blown out downwardly in a film-like configuration through the air blown-out port 08 defined in the outer circumference of the canopy-like hood 07, and since the volume of air to be blown out through the air blow-out port 08 is equal to that of the contaminated air to be withdrawn through the air receiving inlet 012, a short-circuit in a flow occurs easily between the outlet air stream and the inlet air stream. Consequently, it is not only difficult to form a local working space 011 surrounded by the air curtain 09, but also the canopy-like hood 07 must be enlarged in diameter in order to enlarge this local working space 011, and thereby significantly increasing the flow velocity of the film-like air stream which is blown-out through the air blown-out port 08. Furthermore, such arangement results in a canopy-like hood 07 with a complicated structure, and the need of double-duct 03 not only incurrs added costs, but also entails cumbersome handling and installing works. A portable type air conditioner, i.e., a so-called spot cooler has been suggested in the prior art for the purpose of cooling a limited local space in the air. This spot cooler, however, is designed to blow out a cooling air directly against humans and objects, and can serve for only a very limited space, and besides humans feel uncomfortable for a cooling air passing around them at a high velocity. Patent document DE-A-1803 740 describes a zone-forming apparatus, wherein said apparatus comprises jet-stream generating means (1), and a guide member (1d) having a canopy-like guide surface for diffusing a jet-stream which is emitted from said jet-stream generating means to guide it in contact with and along the central portion toward the outer circumference. Cited reference is intended to produce an expanded flow by means of conventional mixed-flow fans la and lf. However, still because of insufficiency of its operation, said reference provides a deviation plate ld to deflect the fan-discharged flow further outwardly so that the fan-discharged flow can strike said deviation plate 1d, thus expanding the flow forcibly. Therefore, said reference, DE-A-18 03 740 attempts to deflect the flow under force, as explained above so that the irregularities of the flow are enormous and the direction of the flow is diffucult to become steady until it tends to easily mix with the surrounding flow downstream of said deviation plate 1d, the reach of the discharged flow becomes unsatisfactory and the formation of a flow zone becomes worsened. The present invention has been made in order to solve the above-described problems and its purport resides in a method for forming a zone surrounded by an air stream where in the film-like annular stream can form a zone of a diameter larger than that of the circumferential edge of a guide member. The method makes use of known means of an apparatus comprising air jet-stream generating means and a flow guide member. Said flow guide member has a canopy-like guide surface forming an almost spherical or conical surface in part. The steps are: generating a jet-flow by means of said jet-flow generating means; causing said jet-flow to impinge upon the central portion of the canopy-like guide surface in order to create a stream in contact with the guide surface which diffuses outwards and in a radial direction towards the circumferential edge of the guide member; causing said stream to flow out from the entire circumferential edge in an angular lower direction so as to create a film-like annular stream which encloses a zone of recirculating air in the webside space immediately underneath said canopy-like guide surface. In a suitable embodiment of the invention the diameter of flow out of the jet from said jet-generating means is smaller or larger, or almost equal to, than that of flow out of the jet from said flow guide member. In an other suitable embodiment said jet-generating means are positioned at the concave or convex side of curved surface of said flow guide member. According to the present invention, a jet-stream which has been emitted from the jet stream generating means is diffused to flow along the central portion of the guide member toward its outer circumference, while being guided to flow in contact with and along the canopy-like guide surface of the guide member. Thus, the jet stream flows out in a film-like configuration from the entire outer circumference of guide member toward the webside direction, i.e., in a radial direction of the guide member. This film-like fluid flow is attracted toward each other, and thus a zone is formed in a space located at the webside of the guide member and surrounded by the fluid stream. Thus, though the method is inexpensive, it can serve to form a zone with a diameter larger than that of the guide member in an easy manner. By utilizing this method, it is made possible to arrange a wall surface on a webside of the guide member, the wall surface being in opposition with the web with a predetermined spacing maintained relative to the latter. Thus, a zone of increased diameter can be formed between the guide member and the wall surface. The method also permits the jet-stream generating means to be arranged either on the concave side or the convex side of the guide member. When the jet-stream generating means is provided on the convex side of the guide member, a zone with an increased diameter can be formed, which is larger than in the case that the jet-stream generating means is provided on the concave side of the guide member. By arranging a diffusion plate which covers the canopy-like guide surface, it is possible to make even the thickness of the film-like fluid stream which flows out of the outer circumference of the guide member, and thereby shilding the zone completely from the space. Furthermore it is possible to arrange a diffusion plate which is in opposition with the jet-stream emitted from the jet-stream generating means, and the outer circumference of the diffusion plate is faced toward the canopy-like guide surface of the canopy-like guide member with a spacing maintained ralative to the latter. In this manner, the fluid can be guided to flow along the canopy-like guide surface by means of this diffusion plate which is provided to be in opposition with the jet-stream emitted from the jet-stream generating means and having its circumferential portion located so as to face toward the canopy-like guide surface of the guide member with a spacing maintained relative to the latter. Moreover, the jet-stream generating means may be provided with an axial impeller. Furthermore, the guide member may allow its canopy-like guide surface to be formed as a rotary surface to be rotatable about the central axis of the guide member. An alternative embodiment of the present invention has been made in order to solve the above-described problem, and its purport resides in that, the apparatus according to inventive method comprises a guide member having a inclined canopy-like guide surface which is arranged on a fixed surface so as to be in opposition with the fixed surface with a predetermined spacing maintained relative to the latter, the guide surface being inclined from the central portion to extend along the outer circumference toward the fixed surface, a stream generating means for withdrawing a fluid from outside and inside the guide member and emitting the same toward the central portion of the guide surface, and a jet-stream regulating means located in a zone surrounded by a film-like jet-stream which flows out from the outer circumference of the guide member. According to the present invention, the fluid is withdraw from outside and inside of the guide member and then emitted toward the central portion of the canopy-like guide surface by the jet-stream generating means, and the jet-stream is diffused to flow along the canopy-like guide surface from the central portion toward the outer circumference of the guide surface, so that a zone may be formed between the guide member and the fixed wall and surrounded by a film-like jet-stream which flows out from the outer circumference. The fluid inside the zone is regulated by means of fluid regulating means provided inside the zone. In this case, the film-like annular jet-stream is forced to flow in a radial direction along the outer circumference toward the fixed wall, and therefore a zone may easily be formed between the guide member and the fixed wall and having dimensions larger than those of the guide member. Because the re-circulation of the fluid takes place within the zone under the forcing action of the film-like annular jet-stream, the fluid in the zone may be regulated efficiently by means of fluid regulating means provided in the zone. Moreover, the apparatus can permit the guide member and the jet-stream generating means to be integrally formed and still allow them supported or suspended in the air downwardly by means of strut. Other features of the method of the invention will be clear from the following discription of variants given by way of examples and illustrated by the drawings in which Fig. 1 is a cross-sectional view conceptionally illustrating the the invention; Fig. 2 is a cross-sectional view conceptionally illustrating another aspect of the invention; Fig. 3 is a cross-sectional view conceptionally illustrating the jet-stream generating means and the guide member. Fig. 4 is a cross-sectional view conceptionally illustrating the jet-stream generating means, guide member and the cover plate. Fig. 5 is a cross-sectional view conceptionally illustrating the jet-stream generating means, guide member and the diffusion plate; Fig. 6 is a cross-sectional view conceptionally illustrating the jet-stream generating means, guide member and the diffusion plate. Fig. 7 is a cross-sectional view conceptionally illustrating the impeller and the guide member. Fig. 8 is a cross-sectional view conceptionally illustrating the jet-stream generating means and the guide member Fig. 9 is a cross-sectional view conceptionally illustrating by way of example a prior art apparatus. Fig.1 illustrates the invention, wherein there are shown a canopy-type guide member 1 and jet-stream generating means 2 which serve to generate a fluid jet stream and is located behind the guide member 1. The jet-generating means 2 comprise a cylindrical casing 21, an impeller 22 provided in and coaxially with the cylindrical casing 21, a motor 23 for driving the impeller 22, and a stay 24 for fixing the motor 22 on the casing 21. The guide member and the jet-generating means 2 are supported in a space 4 by suspending them from a ceiling etc., or alternatively supported by utilizing a strut and other suitable means. Upon the jet-generating means 2 being operated, however, a jet stream A which is emitted from the jet-stream generating means 2 impinges against the central portion of the canopy-like guide surface 1a located behind the guide member 1 and thus is diffused to flow in a stream B in contact with the guide surface 1a toward a circumferential edge 1c from which it then flows out in a film-like annular stream C toward an angular lower direction, i.e, toward and in the radial direction of the web of the guide member 1. The annular jet-stream has its diameter enlarged as it flows further, and then has its diameter reduced to merge again into a stream E. Thus, a local closed space, i.e, a zone 3 is formed in the space 4 which is surrounded by the stream C, and a recirculating stream D is created in the zone 3. That is, the pressure in the zone 3 is lower than that in the space 3, because the annular stream C has the property of entrainment, that is, of withdrawing and dragging its surrounding air therealong while it flows. Thus, the stream C attracts each other to bend the stream line of the jet-stream C with the result that the stream line of the jet-stream C may be determined such that a negative pressure may be balanced with centrifugal forces (diffusion forces) which act upon the jet-stream C. Fig. 2 illustrates a situation where a wall surface 5 of the floor or the ground and the like is arranged at the webside of the guide member such that the surface 5 may be opposed with a predetermined space maintained relative to the web, and thereby forming a zone 3 between the wall surface 3 and the guide member 1. Otherwise the situation is as figure 1. When the annular jet-stream C impinges against the wall surface 5, it is split into a stream F which is then diffused outwardly to flow along the wall surface 5, and a stream G which then flows inwardly into the zone 3. The stream G which flows inwardly into the zone 3 acts to reduce a negative pressure in the zone 3, and thereby increasing the dimension of the zone 3 larger than that when the zone 3 is clear of wall surface 5. Fig. 3 illustrates an arrangement the same as those in figs 1 and 2, excepting that the jet-stream generating means 2 is provided at the webside of the guide member 1. The jet-stream which is emitted from the jet-stream generating means 2 impinges against the central portion of the canopy-like guide surface 1b located at the webside of the guide member 1 and then flows along the guide surface 1b. The negative pressure in the zone 3 is elevated higher in this embodiment than in the first and second arrangements, because the jet-stream generating means 2 withdraws the air from the interior of the zone 3, and consequently the size of the zone is rendered smaller than in the arrangements of figs 1 and 2. Fig. 4 illustrates an arrangement wherein a cover plate 11 is provided above the canopy-like guide surface 1a behind the guide member 1 with a slight clearance maintained therebetween so as to cover the canopy-like guide surface 1a. The inner circumferential edge of the cover plate 11 is jointed with the outlet end of the casing 21 or the jet-stream generating means 2. The stream B which flows along the canopy-like guide surface 1a is not sensitive to a disturbance, such as for example, a motion of the air inside the space 4, and thereby making it possible to make even the thickness of the film-like jet-stream C which flows out of the outer circumferential edge 1c, whereby completely shielding the zone 3 from the space 4. In fig. 5 a diffusion plate 6 is arranged to precisely oppose with the jet-stream A which is emitted from the jet-stream generating means 1, the diffusion plate 6 having its circumferential portion faced toward the canopy-like guide surface 1b located at the webside of the guide member 1 with a slight clearance maintained therebetween. The guide member 1 has its inner circumferential edge jointed with the outlet end of the casing 21. The jet-stream A which is emitted from the jet-stream generating means 2 impinges against the diffusion plate 6 and then is diffused. The diffused stream is guided by the diffusion plate 6 to flow along the canopy-like guide surface 1b located at the web side of the guide member 1. This arrangement is less sensitive to disturbance, and because the jet-stream generating means 2 withdraws the air from the space 2, the zone is not small in dimensions. In fig. 6 an arrangement which is the same as that of fig 5 except that the jet-stream generating means 2 is arranged at the webside of the guide member 1 so that an air stream may flow along the canopy-like guide surface 1a. In Fig. 7 an arrangement wherein the jet-stream generating means comprises an axial impeller 9 driven by a motor 8 is shown. An air stream which flows out from the axial impeller 9 flows along the canopy-like guide surface la located behind the guide member 1. Fig. 8 illustrates an arrangement wherein the canopy-like guide surface 1a is located behind the guide member 1 and formed to provide a conical surface. The configuration of the guide surface 1a affects the diameter of the zone 3 and a position where the jet stream C merges each other, but any conical, spherical and a hyperbolic curved surface etc., may be used as long as it is defined as a rotary surface to be rotatable about the central axis of the guide member 1. The present invention has thus been described as to the formation of a zone which is surrounded by an air stream in an ambient air, but air is not the sole zone-forming medium, and such zones may naturally be formed in any gas, and fluid etc., by emitting it as a jet-stream.

Claims: A method for forming a zone surrounded by an air-stream by means of an apparatus, comprising: air jet-stream generating means (2); a flow guide member (1) said flow guide member (1) having a canopy like guide surface (1a) forming an almost spherical or conical surface in part, characterized by the steps of: generating a jet-flow (A) by means of said jet-flow generating means; causing said jet-flow (A) to impinge upon the central portion of the canopy-like guide surface (1a) in order to create a stream (3) in contact with the guide surface (1a) which diffuses outwards and in a radial direction towards the circumferential edge (1c) of the guide member (1); causing said stream (B) to flow out from the entire circumferential edge (1c) in an angular lower direction so as to create a film-like annular stream (C) which encloses a zone (3) of recirculating air in the webside space immediately underneath said canopy-like guide surface. A method for forming a zone surrounded by an air-stream according to claim 1, characterized in that the diameter of flow out of the jet from said jet-generating means (2) is smaller than that of flow out of the jet from said flow guide member (1). A method for forming a zone surrounded by an air-stream according to claim 1, characterized in that the diameter of flow out of the jet from said jet-generating means (2) is larger that, or almost equal to, that of flow out of the jet from said flow guide member (1). A method for forming a zone surrounded by an air-stream according to claim 2 or 3, characterized in that said jet-generating means (2) is positioned at the concave side of curved surface of said flow guide member (1). A method for forming a zone surrounded by an air-stream according to claims 2 or 3, characterized in that said jet-generating means (2) is positioned at the convex side of curved surface of said flow guide member (1).

Inventors: AOKI YOSHIAKI C O NAGOYA TECHN, IMAIDA TSUYOSHI C O NAGOYA TEC, KONDO FUMIO C O NAGOYA TECHNIC, MAKI YUJI AIR-CONDITIONING REF, NOZOE HIROKI AIR-CONDITIONING, WATABE SHIN AIR-CONDITIONING R, AOKI, YOSHIAKI, C/O NAGOYA TECHNICAL INSTITUTE, IMAIDA, TSUYOSHI, C/O NAGOYA TECHNICAL INSTITUTE, KONDO, FUMIO, C/O NAGOYA TECHNICAL INSTITUTE, MAKI, YUJI, AIR-CONDITIONING & REFRIG. MACH. WORKS, NOZOE, HIROKI, AIR-CONDITIONING & REFRIG. MACH. W., WATABE, SHIN, AIR-CONDITIONING & REFRIG. MACH. W., Maki, Yuji, Air-Conditioning &amp; Refrig. Mach. Works, Nozoe, Hiroki, Air-Conditioning &amp; Refrig. Mach. W., Watabe, Shin, Air-Conditioning &amp; Refrig. Mach. W.
Applicants: MITSUBISHI HEAVY IND LTD, MITSUBISHI JUKOGYO KABUSHIKI KAISHA
Application year: 1990
Main classification: F24F7
IPC codes: F24F9