Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F9/00—Use of air currents for screening, e.g. air curtains
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F9/00—Use of air currents for screening, e.g. air curtains
  • F24F2009/007—Use of air currents for screening, e.g. air curtains using more than one jet or band in the air curtain

Definitions

• the present invention relates to a device for separating a first and a second zone in which different atmospheres prevail.
• Atmosphere here designates the aeraulic conditions, the gas and particulate concentrations, and in particular the concentration of contaminating agents, the pressure and temperature conditions, the hygrometry, etc.
• the invention finds a particularly advantageous application in the industrial fields of the food industry, medicine, biotechnology, electronics, nuclear, and chemistry, in which it is necessary to maintain different atmospheres in areas communicating with each other, while allowing frequent passage of objects or products from one area to another.
• Protection by mechanical airlock consists in interposing between two zones to be isolated from each other, an area where the air is controlled, separated from said areas by watertight doors that can be actuated for their opening and closing.
• the main drawback of such a mechanical airlock is that the transfer of products or objects from one zone to another via said airlock can only be done at low rates due to the opening and closing doors of it.
• ventilation protection In the case where the area to be protected contains a product liable to be contaminated by ambient air, ventilation protection consists in injecting into the area to be protected, a laminar flow which blows towards the outside through the opening access to this area. In the opposite case, where it is a question of protecting the personnel and the environment located outside of a contaminated space, dynamic containment is ensured by implementing extraction ventilation in this contaminated space. In both cases, a rule of thumb imposes a minimum speed of the ventilated air from the or ⁇ Ve of 0.5 m / s in the opening plane through which the two zones communicate, in order to avoid transfer, contamination in the protected area.
• this ventilation protection technique requires treating and controlling, as the case may be, the entire area to be protected, whether it is the clean area or the contaminated area.
• this ventilation protection technique provides only one-way protection, that is to say that it acts only when contamination transfers are only possible in one direction.
• the air curtain protection technique consists in simultaneously injecting, into the separation zone by which the two zones communicate, one or more jet of clean air, adjacent (s) and in the same direction, which forms ( nt) a fictitious door between the area to be protected and the contaminating area.
• the documents FR - A - 2 530 163 and FR - A - 2 652 520 propose systems which use an air curtain to separate a polluted zone and a clean zone.
• the air curtain is formed by two adjacent clean air jets in the same direction.
• the dynamic separation is here ensured by a first relatively slow air jet, the sting of which covers an entire opening.
• the second relatively fast jet compared to the slow jet, is positioned between the slow jet and the clean area. Its function is to stabilize the slow jet, by a suction effect which presses the latter against the fast jet.
• Document FR-A-2 652 520 proposes simultaneously injecting clean air for ventilation, at the temperature adapted to the need, inside the clean air curtain to be protected.
• this clean ventilation air must be injected at a flow rate substantially equal to the flow rate induced by the face of the rapid jet of the air curtain, which is in contact with the clean ventilation air. Furthermore, in document FR - A 2 659 782, it is proposed to add a third relatively slow clean air jet to the two clean air jets used in the systems described in documents FR - A - 2 530 163 and FR - A - 2 652 520, so that the fast jet is located between two adjacent slow jets of the same direction
• the problem of transferring objects or products at high speed between the two zones in which different atmospheres prevail, without breaking the confinement of said zones , is absolutely not resolved satisfactorily by any of the known devices, in particular in the case where there is a risk of cross contamination between the two zones.
• the air curtain technique does not make it possible to correctly solve the problems in particular of transfer of contamination linked to a possible overpressure in one of the zones to be separated.
• document DE 1 087 787 discloses an airlock for separating a first and a second zone in which different atmospheres prevail
• this airlock has the form of a channel which is bounded externally by the ground, a side wall and a horizontal cover wall. A flow of protection is blown into this channel by slots supplied with air and distributed in the side wall, the ground and the honzontale wall of cover This flow of protection is breathed in so that when it leaves the canal, it fills the entire section of said canal
• the protection flow has a sufficiently high speed to form a barrier to an air path directed through the channel in the opposite direction to it.
• the invention provides a new improved device for separating a first and a second zone in which different atmospheres prevail, which has great efficiency and makes it possible to create an insurmountable barrier between the two zones, resistant to the flow of air, in particular to block the passage of contamination from one zone to the other while allowing the high-speed transfer of objects or products between the two zones without to do this, break their confinement, including in the case where there is a risk of cross-contamination between them.
• the separation device is characterized in that it comprises:
• a buffer zone which extends along a longitudinal axis X between the first and second zones, which communicates by an entry with the first zone and by an exit with the second zone, and which is delimited by two vertical walls facing the one of the other which extend along the axis X, comprising perforated sheets,
• insufflation means capable of blowing sterile and clean air into said buffer zone through said perforations of said vertical walls
• - air injection means emerging at the entrance to the buffer zone, and capable of injecting on either side of said longitudinal axis X, in the direction of the exit from said buffer zone, two jets of clean air at high speed, extending in directions oblique to the X axis, which intersect in a region between the entrance and the central region of said buffer zone so as to form an impassable barrier which separates said first zone of said second zone.
• This impassable barrier according to the invention is created in a first part of the buffer zone located between its entrance and its central region.
• the barrier created in the separation device according to the invention can advantageously also constitute a brake between an overpressure zone and the outside in order to limit the flow of air leaving the overpressurized area towards the outside.
• the longitudinal axis X of the buffer zone is a horizontal axis
• the air injection means comprise vertical slots provided on the internal faces of the walls vertical delimiting said buffer zone, said slots being positioned at the entrance to the buffer zone, on either side of said longitudinal axis X facing each other, and supplied with clean air.
• four vertical slots may be provided on each of the vertical internal faces opposite the buffer zone.
• the pressure resistance capacity of the separation device according to the invention and more particularly of the buffer zone of this device is substantially proportional to the flow of air blown through said slots or even to the square of the speed. blowing clean air injected through said slots.
• the buffer zone is delimited by two opposite vertical walls, a bottom and a ceiling which form a rectangular parallelepiped whose cross section is of the order of 0 , 2 m2, and the air injection means inject through said slots jets of clean air at a rate of the order of 400 m3 / h so that the impassable barrier formed inside said zone of buffer is capable of withstanding a pressure difference between the outlet and the inlet of the buffer zone of between approximately 5 and 10 Pascals.
• the insurmountable barrier created inside said buffer zone further reduces the rate by a factor of 10 contamination transferred between entry and exit.
• the ratio between the flow of sterile and clean air injected through said perforations and the flow of clean air jets injected at the inlet of said buffer zone in the direction of its exit is between approximately 0, 5 and 1.
• FIG. 1 is a schematic perspective view of the separation device according to the invention
• FIG. 2 is a schematic view in longitudinal section of the device of FIG. 1, positioned between a first and a second zone,
• FIG. 3 is a schematic front view of a test bench of the separation device according to the invention.
• FIG. 4 represents curves of test results carried out on the test bench of FIG. 3.
• FIGS. 1 and 2 show a device 100 for separating a first and a second zone 10, 20 in which different atmospheres prevail
• the first zone 10 is ICI a zone to be protected, for example a clean area in which the air is sterile and which usually prevails a slight overpressure t
• the second area 20 is for example a dirty zone at the atmospheric pressure, wherein the air is loaded with contaminants
• the separation device 100 represents in FIGS. 1 and 2 HERE has two vertical walls 110a facing each other, a ceiling 110c and a bottom 110b which form a rectangular parallelepiped and delimit between them a buffer zone 110
• This zone buffer 110 extends along a longitudinal axis X, HERE horizontal, between the first and second zones 10, 20
• the buffer zone 110 has a length of approximately 0.8 m and a cross section of the order of 0.2 m2.
• the buffer zone 110 communicates by an entrance 111 with the first zone 10 to be protected. or to be confined and by an outlet 112 with the second zone 20
• the surfaces of the inlet 111 and the outlet 112 of the buffer zone 110 are identical and correspond to the cross section thereof.
• the separation device 100 includes air injection means 120, 120a which open at the level of the inlet 111 of the buffer zone 110 and which are capable of injecting on either side of the axis.
• longitudinal X of said buffer zone 110 in the direction of its outlet 112 two jets of clean air 121, 122 at high speed in oblique directions Y1, Y2 relative to said axis X so that these two jets of clean air 121, 122 meet approximately in a central region 113 of said buffer zone 110
• the air injection means comprise vertical slots 120a, here four vertical slots 120a, provided on each of the internal faces of the vertical walls 110a delimiting said buffer zone, positioned at the entry 111, on the one hand and on the other of said longitudinal axis X facing each other and facing towards said buffer zone 110
• the slots 120a are supplied with clean air by means of conduits 120 connected to inlets clean sterile air 101 provided on the upper part of the vertical walls 110a of the separation device 100.
• the air flow injected through said slots 120a is of the order of 430 m3 / h, which corresponds to a flow rate in the buffer zone of 0.7 m / s.
• FIG. 2 shows more particularly the ventilation operation of the separation device 100.
• This air jet 123 cannot stably remain in the middle of the buffer zone 110 and moves laterally to catch on one of the two vertical walls 110a of the separation device 100, according to a conventional behavior of the jets.
• This phenomenon of catching the air jet 123 on one of the walls 110a of the separation device 100 creates two recirculation zones 124, 125 of the air coming from the second zone 20, one of the recirculation zones being closed 124 by the clean air jet 123, the other recirculation zone 125 being open and communicating with the second zone 20.
• FIG. 3 which incorporates the separation device 100, tests carried out on a test bench shown in FIG. 3, which incorporates the separation device 100, have shown that the barrier created inside the separation device as shown in Figures 1 and 2, was able to withstand a pressure difference of between about 5 and 10 Pascals, for a flow of air injected into the slots of the order of 400 m3 / h, preferably, 430m3 / h, the cross section of the buffer zone being of the order of 0.2 m2 and preferably equal to 0.17 m2. .
• This injected air flow corresponds to a flow rate in the buffer zone 110, of the order of 0.7 m / s.
• the pressure resistance capacity of the separation device is approximately proportional to the flow of blown air or to the square of the speed of blowing the air through the slots.
• the vertical walls 110a facing each other comprise perforated sheets and supplied by means of insufflation with sterile and clean air so as to blow clean air into said buffer zone 110 through said perforations
• the supply of sterile air to said perforations 110a ′ takes place via the air inlets 101 provided on the upper part of the vertical walls 110.
• the air inlets 101 provide the sterile air to said perforations, are distinct from those supplying the air ducts 120 to the slots, and vice versa.
• the flow of sterile and clean air injected through the perforations 110a ' is different from that of the air jets 121, 122 injected into the buffer zone 110 via the slots 120a, the ratio of the two flows being between approximately 0.5 and 1, preferably equal to 0.5.
• the flow of clean air injected through the perforations 110a ′ is of the order of 200m3 / h .
• This clean air arrives directly in the recirculation zones 124, 125, which makes it possible to increase the efficiency of the impassable barrier created by the clean air jets, planes 121, 122 in the central zone of the buffer zone 1
• FIG. 3 a schematic assembly of a test bench of the separation device 100 has been shown.
• a clean enclosure 10 equipped with an absolute ceiling filter 3 surmounted by a fan 2 and a prefilter 1.
• This absolute ceiling filter 3 makes it possible to create in the clean enclosure a vertical unidirectional flow of air, towards the floor of this enclosure.
• the floor of this clean enclosure 10 consists of removable perforated sheets. This makes it possible to vary its resistance to the passage of air.
• a dirty enclosure 20 supplied with air contaminated by a ceiling fan 12 to put the dirty enclosure possibly under pressure, the ceiling fan of course having no filter.
• the floor of the dirty enclosure is also made of perforated sheets.
• windows 11 and 21 are provided for viewing what is happening inside the enclosures 10 and 20 respectively.
• a filtration box 13 associated with a fan 14 which feeds the arrivals 101 (see Figure 1) provided on the. vertical walls 110a of the suction device 100, for injecting clean air via the conduits 120 of the injection means, through the slots 120a towards the interior of the buffer zone 110 of the separation device 100.
• a conveyor 5, the geometry of which is adapted to that of the buffer zone 110 passes through said buffer zone 110 of the suction device 100 to transfer products or objects from the clean enclosure 10 to the dirty enclosure 20 at high speed, and vice versa .
• the assembly is mounted on supports 4 placed on the floor of the test room. By playing on the air flow rates created by the fans 2 and 12, it is then possible to modify the pressures in each of the chambers and thus create a pressure difference across the terminals of the separation device 100.
• the operating conditions of the suction device 100 in the test bench as shown in FIG. 3 are as follows:
• the air flow leaving the slots is of the order of 432 m3 / h, - no supply of the perforated vertical walls.
• FIG. 4 The results obtained during these tests appear in FIG. 4 on which various curves are represented for different values of pressure difference between the inlet and the outlet of the buffer zone of the separation device 100, the dirty enclosure 20 being overpressure.
• the impassable barrier created in the central part (located at about 0.4 m abscissa) of the buffer zone of the separation device according to the invention is capable of withstanding a pressure difference of around 10 Pascals, which is quite interesting.
• the pressure difference between the inlet and the outlet of the buffer zone is 21 Pascals, it can be verified that the separation device according to the invention makes it possible to reduce by a factor of 10 the rate of contamination transferred between the dirty enclosure and clean enclosure.

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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)
• Air Bags (AREA)
• Separation By Low-Temperature Treatments (AREA)
• Housing For Livestock And Birds (AREA)
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• 1997
  • 1997-03-03 FR FR9702486A patent/FR2760199B1/fr not_active Expired - Fee Related
• 1998
  • 1998-02-27 US US09/380,479 patent/US6146267A/en not_active Expired - Fee Related
  • 1998-02-27 EP EP98912564A patent/EP0966638B1/de not_active Expired - Lifetime
  • 1998-02-27 CA CA002283129A patent/CA2283129C/fr not_active Expired - Fee Related
  • 1998-02-27 ES ES98912564T patent/ES2175695T3/es not_active Expired - Lifetime
  • 1998-02-27 JP JP53822098A patent/JP3851355B2/ja not_active Expired - Fee Related
  • 1998-02-27 WO PCT/FR1998/000388 patent/WO1998039604A1/fr not_active Ceased
  • 1998-02-27 AT AT98912564T patent/ATE217069T1/de not_active IP Right Cessation
  • 1998-02-27 DE DE69805169T patent/DE69805169T2/de not_active Expired - Fee Related

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