Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
  • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
  • F24F3/16—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by purification, e.g. by filtering; by sterilisation; by ozonisation
  • F24F3/163—Clean air work stations, i.e. selected areas within a space which filtered air is passed

Definitions

• the present invention relates to close protection of a ho ⁇ zontal work plan by means of a clean air flow.
• the invention relates to both a method and a device providing such protection.
• the invention relates more precisely to the protection of a work surface which is free, and therefore accessible, both on top and on at least one side, called the free side, of this work surface.
• a clean room - in which the air is filtered and treated so as to present a given level of cleanliness.
• the main drawback of this solution is the difficulty of maintaining air quality in a large volume at acceptable economic conditions.
• Another drawback is the fact that the staff must be dressed in a special outfit, itself sté ⁇ le, whose cleanliness is difficult to maintain flawless and to control, and whose wearing is tedious.
• the personnel and materials present in the work room can be sources of air pollution.
• the work surface is thus protected by a clean air shield which protects objects from external contamination, although the rest of the room in which the work surface is located contains air likely to be polluted. , the personnel assigned to tasks relating to said objects which may therefore be subject to less strict hygienic constraints.
• This work plan can be a fixed tray, on which are placed articles to undergo treatment or be subjected to any operation, either manual or automated.
• It can also consist of a conveyor, for example a movable mat, which successively brings articles to be treated to the work station, and then evacuates them, when the operation is finished.
• a conveyor for example a movable mat
• the articles are, for example, containers which are transported in line with the moving conveyor, and the filling of which is effected by a dispensing head arranged in the protected area, so that the product filling is free from contamination.
• the state of the art in this area can be seen in the documents FR-A- 1 257 562 and EP-A-0 375 343.
• the document FR-A- 1 257 562 relates to a device for maintaining an atmosphere having characteristics determined in a room open on one side.
• This room has a floor constituting a horizontal work surface above which flows a stream of clean air.
• the chamber is open on only one of its sides, accessible to an operator, and this side is traversed by a second stream of clean air, which takes the form of an approximately vertical water, diverged from top to bottom.
• the air is sucked in at the front edge (side or side of the chamber) of the working surface and is recycled via an atmosphere regeneration device, so that it travels in a closed circuit.
• the device which is the subject of document EP-A-0 375 343 comprises a horizontal work plan which is exposed both on the top and on one of its sides.
• This chamber produces a double flow, namely a horizontal flux passing over the work surface, and a multi-directional lux formed of a plurality of small jets produced by holes formed in the various partitions of the chamber
• Cylinder arc shaped guides lining the interior of this chamber ensure the deflection of the air coming from the box to produce the above-mentioned horizontal flow. If this known device has the advantage of its accessibility at the time by one of the sides of the worktop key from above, it nevertheless has the disadvantage that the distribution of the velocities of the horizontal flow, above the work plan, is constant.
• the close protection method object of the invention which aims to protect, by means of a f lux of clean air, a horizontal work plan clear and accessible both on the top and on at least one side, called free side, is remarkable :
• clean air is continuously blown over the worktop from the side opposite to said free side, and called upstream side, in the form of a substantially horizontal flow which sweeps the worktop transversely, towards the free side, and which has a speed gradient such that the upper layer - or upper vein - has a speed significantly greater than that of the air circulating in the vicinity of the upper face of the work surface;
• the subject of the invention is also a device for close protection of a horizontal work surface by means of a clean air flow, in which the work surface is clear and accessible on the top and on the surface. at least one side, called the free side.
• This device is remarkable for the fact that it includes:
• upstream side means for continuously blowing clean air above the work surface from the side opposite to said free side, and called upstream side, in the form of a substantially vertical flow which sweeps the work plane transversely, in the direction of the free side, and which has a speed gradient such that the upper layer - or high layer - has a speed substantially greater than that of the air circulating in the vicinity of the upper face of the work surface,
• - suction mouth extending along and in the immediate vicinity of the edge of the worktop; - suction means connected to said mouth.
• a single flow generator such as a fan (or a group of juxtaposed fans), ensures the blowing of clean air upstream side and its suction on the free side, at least part of the flow being recycled by a circuit path closed ;
• - Insufflation of air is carried out by means of a flow generator, such as a fan downstream of which is disposed at least one filter, or other means of purification.
• a flow generator such as a fan downstream of which is disposed at least one filter, or other means of purification.
• a flow generator such as a fan
• a substantially vertical flow which is deflected at 180 ° to the level on the upstream side by a tubular guide of semi-cylind ⁇ que, or approximately semi-cylind ⁇ que shape
• Said air blowing means comprise a vertical duct, or approximately vertical, disposed on the upstream side, the lower end of which is connected to an air flow generator such as a fan, while its upper end opens out , substantially at the level of the working plane, in a tubular guide in the form of a quarter cylinder, or approximately in the form of a quarter cylinder, capable of deflecting the flow to give it a substantially horizontal direction;
• Said vertical duct or approximately vertical, is provided internally with at least one deflector forming an acute angle relative to the vertical, and capable of deflecting part of the flow towards the outside (relative to said working plane) in order to constitute said high vein;
• the duct is provided with several deflectors, which are constituted by juxtaposed flat plates arranged in a fan, so as to diverge from the bottom to the top;
• tubular guide is internally lined with at least one deflector in the form of an arc of a cylinder, coaxial with the guide;
• Said air insufflation means are provided with an overhanging part, forming a visor, which overhangs the upstream area of the work surface and is adapted to fold down the upper vein slightly;
• suction mouth is subdivided into two secondary suction mouths: the upper one, able to capture the air flow corresponding to the upper vein and to let it pass without - or practically without - pressure drop, l 'other lower, able to brake the ⁇ ux located under the upper vein, for example by means of a constriction; - the worktop is a fixed tray;
• the work plan is a transporter.
• transporter is meant both a single transporter and a group of two or more of two transporters arranged side by side, for example several adjoining belts.
• FIG. 1 is a schematic view, cut by a transverse vertical plane, of a first embodiment of a device according to the invention, the cutting plane being referenced I-I in FIG. 2.
• FIG. 2 is a top view of the device of Figure 1;
• FIG. 3 is a schematic view, similar to Figure 1, of a second embodiment of the device;
• - Figure 4 is a diagram showing a third embodiment, also cut by a vertical transverse plane
• - Figures 5 and 6 are diagrams, respectively in perspective and in section, through a transverse vertical plane, of a part of the insufflation and air deflection system capable of equipping the devices;
• FIGS. 7 and 8 are diagrams, respectively in perspective and in cross section, of a fourth possible embodiment of the device;
• - Figure 9 is a curve representative of a possibility of variation of the speed within the clean air flow above the work plane, as a function of the distance from the measurement point relative to this plane;
• FIGS 10 and 1 1 are perspective diagrams showing two carriers capable of being associated with a device according to the invention
• FIGs 12, 13 and 14 are illustrations showing the configuration of the flow of air in three devices of different geometry, the representations resulting from simulations made by computer, the appreciation of the speeds becoming easier with reference to a gray scale, which goes from the lightest to the darkest, in the direction of the increasing speeds your.
• Figures 1 and 2 which represent a first possible embodiment of the device, there is designated by reference 1 a work surface which, in this case, is a ho ⁇ zontal t ixed tray, of rectangular shape, supported by a piememcnl S.
• the upper face 10 of the work surface is intended to receive articles to be subjected to any manipulation and / or treatment which must take place in a clean atmosphere.
• the longitudinal edges of the plate 10 have been designated by the references 10a and 10b. These preferably have a rounded profile (without sharp edges)
• transverse edges 10c are in abutment against a pair of transverse partitions 12 which extend upwards over a certain height relative to the level of the work surface 1.
• a box 2 Under the tray 1 is installed a box 2. It is a tubular conduit extending under the entire tray 1, and ensuring transverse communication from one side to the other of the device.
• the box 2 is fixed to the plate 1 and / or to the base 1 1 by appropriate members, not shown.
• a system 4 for generating an air flow consisting of one or more electric fan (s) capable of sucking air at the inlet 20 of the box, edge side 10b, to inject it on the other side, on the edge side 10a.
• the air inlet portion 20 of the box has a smaller section than the main portion 22 which receives the generator 4.
• This portion 20 constitutes a suction mouth located under the plate 1, j uste near the rim 10b.
• the transition between the narrowed portion 20 and the main portion 22 takes place via a divergent portion 21.
• the main portion 22 opens into a semi-cv lind ⁇ quc guide 3, whose radius corresponds to the height of the portion 22, and whose axis of revolution is located at the location of the edge 10a.
• the guide 3 whose inner wall is referenced 30, opens above the plate 1, plumb with the edge l dua.
• box 2 and the guide 3 are closed on their transverse sides, by suitable transverse walls.
• an air purification or filtration device 5 composed for example of one or more filter pads.
• the filter elements are of known type, adapted to retain impurities or particles present in the air supplied by the generator 4.
• composition and porosity of these elements are chosen according to the application, and in particular according to the degree of cleanliness required.
• the operation of the device is illustrated in FIG. 1, arrows symbolizing the path of the air intended to protect bottle A on the worktop.
• the length of the various arrows was chosen so that it is approximately proportional to the speed of the air flow at the location considered.
• the device shown in FIGS. 1 and 2 constitutes a work station for a person (not shown) assigned to a certain task on article A, this person standing on the free side of the device, referenced 100, which side corresponds to the edge 10b.
• This side 100 will conventionally be called “free side”.
• the other side, referenced 101, where the guide 3 is located will be called “upstream side”, with reference to the direction of movement of the clean air flow above the work surface.
• upstream side reference to the direction of movement of the clean air flow above the work surface.
• the spaces 100 and 102 being clear and accessible, the operator can place himself without difficulty near the work surface, ⁇ manipulate the articles to be treated, and can involve various instruments or materials, for example mobile filling devices located in the upper space 102
• the generator 4 having been started, it will continuously suck a flow of air through the mouth 20, as symbolized by the arrow a
• the external vein which becomes the upper vein - or high vein - V j, has a speed significantly greater than the rest of the tlux .
• the radius of the guide 3 which determines the height of the air flow supplied by the guide above the work surface, is preferably chosen according to the height of the articles A considered, so that these articles bathe in the flowixiel é ⁇ eur V 0
• the axis of revolution of the semi-cylindrical guide 3 substantially coincides with the boid 10a.
• this arrangement is not compulsory.
• the position of the axis could be shifted, up or down, and the radius modified to adjust the intensity of the speeds of V 0 and V j
• High V i vein acts as a shield f elm vault which protects all the space located above the surf ace 10, that it makes safe from pollution from the ambient air, located in the open upper space 102 and on the open side 100.
• the contamination particles which may be present and which come near the vein Vi are immediately swept away by this flow, and transferred at high speed to the free side 100.
• the air flows from the lower vein V 0 and the upper vein V i are respectively symbolized by the arrows d and e These two flows meet on the downstream side, beyond the free edge 10b, and at least part of the overall flow goes down around the edge 10b - as symbolized by the arrows f - to enter the mouth 20.
• This bypass is f enhanced by the rounded form of the edge 10b.
• the air is thus recycled, at least for the most part; as it is practically clean air, or for the most part clean, the fouling of the filter elements takes place slowly.
• This air circulation is continuous, as long as there are articles to protect on the work surface. Thanks to the transverse partitions 12, the flow of the clean air flow over the work surface is not disturbed, or is practically not disturbed, in the vicinity of the transverse sides 10c of the working plane.
• the device illustrated in Figure 3 comprises a work plan 1 which is constituted not by a fixed plate, but by a conveyor, and more precisely by the upper strand - or strand "go" 13 - of a carpet without l in mobile.
• the return strand extends under the outward strand 13.
• the upper strand 13 transports objects, for example bottles A. These objects must be subjected, at some stage of their journey, to any treatment - for example filling - in a space which must be protected from contamination by the 'ambiant air.
• the device according to the invention is installed on the tra j ectoire carrier, af in the protection of a portion thereof
• the suction mouth 20, at the entrance of the housing 2 has its opening directed horizontally, facing the space j ust above the worktop 1.
• This suction port 20 is bent downwardly along a quarter of cvlmdrc, to connect to a portion lubulairc v crticalc 200 extending along the free side 100
• the tubing 200 connects itself has housing parts 21 and 22 which are similar to those of the first embodiment, and which are installed below the return belt strand 13 'and its support rollers 14', near the ground S.
• the generator 4 is mounted, composed of one or more fans. Via a right angle bend 23, the box 22 itself opens into a tube, or chimney, vertical 6 disposed on the upstream side 101.
• the tube 6 is connected, in its supe ⁇ cure part, to a guide 7 in the form of a quarter cylinder which opens out near the work surface 1, upstream side
• One or more f ⁇ ltrc (s) 5 is (are) monlé (s) at the outlet of the fan or fans 4, for example at the base of the chimney 6.
• the guide 7 which channels the flow of clean air at its entry above the work surface deflects the air only on a quarter of circumference (90 °)
• the speed gradient is such that it there is no significant difference between the velocities measured in the high flow V ⁇ and in the rest of the flow V 0 This is why, in order to obtain a frank increase in the speed distributions in the upper part of the flow, it is expected u in this embodiment, lining the vertical chimney 6 with a series of deflectors 60. These are flat blades, the large faces of which are parallel to the longitudinal edges of the work surface 1, that is to say to the lateral edges of the mat 13.
• a series of three deflectors 60 is provided.
• the internal deflector - that is to say facing the work surface -, referenced 60a, in the figures 5 and 6 is a vertical plane piac.
• the external plate referenced 60c in this same figure is composed of a vertical mfé ⁇ eure zone, of limited height, its main part making an acute angle with respect to the vertical, of direction directed upwards and outwards.
• the intermediate deflector 60b is a plate also inclined with respect to the vertical, in the same direction as the deflector 60c, but with a smaller angle.
• the series of deflectors 60 therefore presents, seen from the side (FIG. 6) the general appearance of the members of a fan which diverges upwards, that is to say downstream if we consider the displacement of the air in the chimney 6 observation of the IGURES 5 and 6 enables to understand the role of spoilers.
• the air flow at the base of the chimney 6 has been designated by the arrows F.
• the guide 7 is also provided with a set of three deflectors 70.
• the internal deflector is assigned the index a, the intermediate deflector of the index b and the external deflector of the index c.
• deflectors are curved plates, in the form of an arc of a cylinder coaxial with the guide 7.
• the deflector 70a is positioned so as to channel the most interior vertical flow F, to give it a horizontal orientation (arrow F ').
• the deflectors 70a and 70b are channeled the major part of the air flow coming from the space located between the deflectors 60a and 60b (arrow G '), while the deflectors 70b and 70c channel between them the major part of the current d 'air from between deflectors 60b and 60c (arrows H').
• the stream of air I of higher speed, which circulates near the internal wall 60 of the chimney 6, after having been channeled by the deflector 60c is guided in the channel formed by the internal wall of the guide 7 and the outermost deflector 70c.
• the operation of the device forming the object of the second embodiment of FIG. 3 is entirely similar to that of the first embodiment, the air being mainly recycled after scanning the work surface, by suction through the mouth 20, passage in the fan 4 and in the filter 5, deflection and channeling in the chimney 6 and the guide 7.
• the air is not recycled.
• the generator - for example a fan - 41 sucks in the ambient air to pulp it after filtration or purification, via a box 8, above the work surface 1
• the suction mouth 20 is connected, via a conduit 2, to a vacuum cleaner 40 separate from the fan 41.
• the box 8 is arranged on the upstream side of the work surface 1 - which can be either a fixed plate or a conveyor -.
• the fan 41 is located at the base of the box.
• the box has a flared portion 81 which opens upwards into a substantially vertical duct 8a extended by a guide approximately in quarter of a cylinder 8b.
• An internal deflector composed of a flat part 800a extending obliquely upwards and outwards and extending, in the guide 8b, by an arc-shaped portion of cylinder 800b, coaxial with the wall of the guide 8b, ensures the correct speed distribution above the work surface
• the air flow is composed of a high vein V], of high speed, which protects a lower vein of reduced speeds V
• V the dimensions of the device according to the invention will of course be adapted to the application concerned, and in particular the size of the articles to be treated
• the air flow generated by the fan (s) will of course be directly dependent on these dimensions, as well as the speed of circulation of the flow.
• the fourth embodiment illustrated in FIGS. 7 and 8 comprises an air insufflation system 6, 7 similar to that of Liguria 5 and 6, and the same references have been used to designate therein identical or similar elements.
• the guide 7 which channels the air above the work surface 1 is extended at the outlet by an overhanging part - or visor 71 - which overhangs the upstream border zone of the plane 1 and is slightly inclined towards the low compared to the ho ⁇ zontale
• the function of this visor 71 is to slightly fold down the high vein V j to orient it towards the top of the suction mouth 20 and to reduce the air leaks above from that mouth
• the partition 24 is disposed in the upper part of the pipe 200, near its outer wall.
• the shape of the partition 24 is similar to that of the portion of the external wall opposite which it is located, these two elements forming a channel whose upper part forms a quarter-dc-ccrcle and whose lower part is rectilinear and vertical.
• the element 25 is fixed against the internal wall of the tube 200 II comprises, from top to bottom, an upper face 250 forming a dihedral converging with the lower portion of the partition 24, a vertical face 251 substantially in the extension of this portion, and a divergent face 252.
• the elements 24 and 25 subdivide the suction mouth 20 into two secondary mouths, one upper and external 20b of constant section and the otherêtlé ⁇ cure and internal 2 ⁇ a of decreasing section until a throttle located at the level of the zone of out of the mouth 20b.
• This arrangement has the advantage of creating in the suction pipe 200 a vertical distribution of speed homologous to that which has been created on the blowing side.
• the suction by the mouth 20 is done with a higher air speed in its upper part
• the vein V t of high speed is stabilized and its tendency to rise under the effect of external disturbances (air currents), or to fall back before the work plan, is reduced.
• the upper secondary mouth 20b in which the air flow is direct (without pressure drop) captures almost all of the upper vein V j.
• the slowing down of the lux in the mouth 20a forms an air mattress which prevents the upper vein V i from falling back down.
• Figure 9 shows, simply by way of example, a possible distribution of the speeds above the work surface in the central zone thereof, within a clean air flow having a height of 0 , 30 m.
• the outside air is assumed to be stationary
• the curve in FIG. 9 represents the distance (height) X, in meters, from the measurement point in relation to the upper face of the work plane.
• the ordinate shows the speed v in meters per second.
• This range corresponds to the low speed vein V 0 .
• the diagram in FIG. 10 represents an installation for depositing topping products on a base which is moved continuously by means of a conveyor belt 13.
• the advance of the conveyor is referenced Di, while the tablecloth removal tool is referenced 90.
• the conveyor 13 has a width of 1.5 m and an advance speed of 5 to 10 m / min.
• the transporter passes inside a protected area by means of a device in accordance with the invention, the outline of which is shown diagrammatically by a broken line, and which is designated D
• the installation illustrated in FIG. 11 includes a conveyor belt 13, the advance of which is done step by step, as symbolized by the arrow D 2
• the belt 13 carries thermoformed trays B intended to receive a product, by example a food product, which is supplied by hand dosing or filling tools 91.
• Each tool 91 is assigned to a tray, the latter being transported in adjacent rows by the mat 13
• the close protection device D is installed at the tools
• FIGS. 12 to 14 relate to modeled flows, calculated by computer
• the air enters the guide according to a uniform distribution of the speeds, the value of the speed being E.
• white arrows are represented, the length of which is proportional to the intensity of speed.
• the distribution of the speeds is represented by a gradation of g ⁇ s, going from the lightest to the darkest in the direction of increasing the speed.
• the speed value is given by the scale shown on the drawing.
• the diagram of FIG. 12 corresponds to a configuration similar to that of the first embodiment, using a semi-cyhndric guide.
• the height of the flow leaving the guide is 0.30 m; the width of the work surface 1 is 0.60 m; the thickness of the worktop is 6 cm; the height of the suction mouth is 9 cm.
• the drawing makes it possible to note the existence of an almost static space (light gray) above the work plan and to visualize the high vein, of high speed (very dark gray) which forms a butcher overhanging the work plan and surrounding the free edge up to the suction mouth.
• FIGS. 13 and 14 relate to devices similar to the second embodiment (FIG. 3). These two views make it possible to distinguish the high and low veins, respectively of dark tone (high speed) and light tone (low speed).
• FIGS. 13 and 14 are on different scales, the height of the flow produced by the guide, upstream side of the work surface, being the same in both cases, namely equal to 0.30 m.
• the width of the work plan is
• the device in accordance with the invention is not necessarily associated with a processing operation for articles supported or transported by the work surface.
• the invention can also be implemented to equip a simple transfer installation, from one hour to another, of sensitive products, so that the products transported are protected from the external environment, possibly polluted.

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• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Ventilation (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
• Grinding Of Cylindrical And Plane Surfaces (AREA)
• Electronic Switches (AREA)
• Sewing Machines And Sewing (AREA)
• Prevention Of Fouling (AREA)
• Processing Of Stones Or Stones Resemblance Materials (AREA)
• Cleaning In General (AREA)

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• 1996
  • 1996-06-21 FR FR9607961A patent/FR2750199B1/fr not_active Expired - Lifetime
• 1997
  • 1997-06-20 ES ES97930559T patent/ES2146108T3/es not_active Expired - Lifetime
  • 1997-06-20 EP EP97930559A patent/EP0906546B1/de not_active Expired - Lifetime
  • 1997-06-20 US US09/202,580 patent/US6095918A/en not_active Expired - Fee Related
  • 1997-06-20 AT AT97930559T patent/ATE192228T1/de not_active IP Right Cessation
  • 1997-06-20 PT PT97930559T patent/PT906546E/pt unknown
  • 1997-06-20 DK DK97930559T patent/DK0906546T3/da active
  • 1997-06-20 CA CA002259455A patent/CA2259455C/fr not_active Expired - Fee Related
  • 1997-06-20 WO PCT/FR1997/001106 patent/WO1997049955A1/fr not_active Ceased
  • 1997-06-20 JP JP10502438A patent/JP2000512730A/ja not_active Ceased
  • 1997-06-20 DE DE69701803T patent/DE69701803T2/de not_active Expired - Fee Related
• 2000
  • 2000-07-19 GR GR20000401666T patent/GR3033981T3/el not_active IP Right Cessation

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