Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B15/00—Preventing escape of dirt or fumes from the area where they are produced; Collecting or removing dirt or fumes from that area
  • B08B15/02—Preventing escape of dirt or fumes from the area where they are produced; Collecting or removing dirt or fumes from that area using chambers or hoods covering the area
  • B08B15/023—Fume cabinets or cupboards, e.g. for laboratories
• • 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 a method and apparatus for eliminating eddy currents in the corners of spaces with laminar air flow, and the use of such apparatus.
• Fig. 1 illustrates how eddy currents occur in a corner, such as is formed by two machines, 2,4 placed in juxtaposition.
• Fig. 2 illustrates how this eddy current formation can be eliminated by separating the apparatuses 2,4, so that the air flow can pass between them and be sucked out via the floor 6.
• FIGS. 3 and 4 there are other examples of the prior art applied to the elimination of eddy currents in laminar air flow.
• a work table 8 is illustrated as being situated in a special cabinet 10 in two different embodiments, with the air supply coming from the upper part of the cabinet. In these examples air exhaustion takes place at 12, 14 and 16 to the side of, and underneath the work table 8.
• FIG. 5 A further, comparatively complicated way of reducing eddy currents in laminar air flow is shown in Fig. 5.
• a space 20 having a work table 18. Air is supplied to the space through the ceiling, this supply being of different magnitudes in different zones I, II, III of the ceiling, as illustrated in the figure.
• an air flow IV is supplied through one of the walls. Examples of the flow rates are given in the figure.
• a special air exhaust cover 22 is arranged above the table 18, and a valve 26 is disposed in a duct 24 conveying air from this cover 22 for regulating the amount of air removed.
• the space under the work table 18 is also in communication with the exhaust space via a perforated wall 28 to the rear of the table. The formation of eddy currents around the work table 18 may be reduced by this arrangement of the air supply and exhaust.
• the object of the present invention is to provide a generally utilisable, simple method of eliminating eddy currents in corners of spaces where laminar air flow is desired, and to achieve a similarly simple, generally utilisable apparatus for this purpose.
• the apparatus in accordance with the invention can be used for the elimination of eddy current formation when air is exhausted as well as when it is supplied, and comprises a baffle formed with a flat or curved, perforated surface. If the surface is flat the optimum angle of inclination of the surface is 30 - 45° in relation to the direction of the laminar flow. Cleaning of the baffle is facilitated by using a curved surface, and further spreading of the air is achieved when air is delivered or blown out through the baffle.
• FIG. 6 illustrates the apparatus in accordance with the invention used for eliminating eddy currents at a work table
• Fig. 7 illustrates the apparatus in accordance with the invention used for eliminating eddy currents when air is supplied to a space via its ceiling.
• a laminar flow cabinet 30 is illustrated in fig. 6, the cabinet being supplied with a laminar air flow via the ceiling 32 thereof.
• a work table 34 is disposed inside the cabinet 30.
• an suction baffle 36 provided with an inclined, perforated surface 38. The corners between the table top and cabinet wall will thus be bridged by the perforated surface 38, through which air is sucked from the space above the work table 34.
• the suction ramp 36 is in turn connected to un illustrated apparatus for removal of the air. An effective elimination of eddy currents in the air at the upper side of the work table 34 is achieved by this exhaust baffle 36.
• the inventive apparatus is also illustrated in Fig. 7, and here it is used at the ceiling through which a laminar air flow is supplied to the space 40 under the ceiling.
• Air is supplied through the ceiling, suitably with the aid of so-called HEPA filters 42.
• the corner region 44 is not accessible for supplying air, due to the construction of the building. This gives rise to the formation of eddy currents in the corner which interfere with the laminar air flow in the space 40.
• This eddy current formation can be eliminated with the aid of the apparatus in accordance with the invention by installing an air exhaustion baffle in the corner between the ceiling 42 and wall 46, so that the inclined, perforated surface of the baffle covers the corner.
• the air exhaustion baffle is configurated and installed such that a certain part of the air blown out through the HEPA filters 42 is taken in behind the baffle and is blown out into the space 40 via the inclined, perforated surface, a substantially laminar air flow thus being obtained from the corner region as well.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Lasers (AREA)
• Ventilation (AREA)
• Air-Flow Control Members (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20383211

Family Applications (1)

Country Status (3)

Citations (5)

• 1991
  • 1991-07-01 SE SE9102038A patent/SE512255C2/sv not_active IP Right Cessation
• 1992
  • 1992-06-26 WO PCT/SE1992/000480 patent/WO1993001455A1/en active Application Filing
  • 1992-06-26 AU AU22912/92A patent/AU2291292A/en not_active Abandoned

Patent Citations (5)

Non-Patent Citations (1)

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