Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L1/00—Enclosures; Chambers
  • B01L1/04—Dust-free rooms or enclosures
• • 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
  • F24F3/167—Clean rooms, i.e. enclosed spaces in which a uniform flow of filtered air is distributed

Definitions

• This invention relates to cabinets of the kind requiring a clean and/or sterile internal air environment.
• a containment dispensing cabinet used for the safe handling of hazardous pharmaceutical preparations, such, for example, as cytotoxic drugs.
• a sterile " isolation cabinet is a sterile " isolation cabinet, usually made from flexible film, and used for medical and pharmacological purposes and being adapted to isolate technicians from processes being carried out therein and substances being used therein, and vice versa.
• a clean air cabinet having an internal worksurface and, associated with the cabinet, a fan system adapted to deliver to the worksurface a uni-directional downward sterile airflow, whereby the whole worksurface is provided and covered with sterile air.
• the fan system recycles the air downwards through grilles from the worksurface through a recycling duct system to a fan chamber via decontamination filter means, usually a HEPA (high efficiency particulate air) filter.
• decontamination filter means usually a HEPA (high efficiency particulate air) filter.
• a clean air cabinet provided with a pass through box having inner and outer doors and fitted with top filter means through which external air can flow into and through the pass through box in downward sterile air flow and from thence under the cabinet worksurface via duct means, under the control of a fan means, into a recycling duct system.
• the clean air cabinet is provided with a working region through which is delivered a unidirectional downward sterile airflow controlled by a recycling fan system which incorporates the fan means for handling the airflow through the pass through box.
• the top fitted filter means comprises a prefilter and HEPA filter.
• Clean air cabinets are also known having filtered clean/sterile turbulent air flows and it is another object of the present invention to provide such a clean air_ cabinet with a unidirectional sterile air flow facility.
• This second aspect of the present invention is achieved by providing a turbulent air flow clean air cabinet, within its working region, with a canopy defining a predetermined zone of the working region for unidirectional downward sterile air flow, the canopy being open at its bottom and provided at its top with air filter means and a recycling fan means.
• the recycling fan means is housed in a chamber which communicates with the canopy interior and with the cabinet working region via HEPA filter means, and with external atmosphere via a prefliter.
• Figs. 1 and 2 illustrate a clean air cabinet in accordance with the first aspect of the present invention in four different operational modes A to D;
• FIGs. 3 and 4 illustrate in front view a clean air cabinet in accordance with the second aspect of the present invention in a first operational mode E and a second operational mode F respectively;
• Figs. 5 is a sectional view on the line X-X of either Fig. 3 or Fig. 4;
• Fig. 6 illustrates a modified clean air cabinet similar to that of Figs. 3 and 4;
• Fig. 7 is a sectional view of a further modified clean air cabinet in an operational mode El;
• Fig. 8 is a fragmentary sectional view corresponding to Fig. 7 in an operational mode Fl;
• Fig. 9 is a fragmentary sectional view of yet another modified clean air room.
• FIG. 1 and 2 illustrate a clean air cabinet in the form of a containment dispensing cabinet which is generally designated 10.
• the cabinet 10 comprises a horizontal work surface 11.
• the cabinet 10 is provided at the front with a door (not shown) horizontally hinged at the top, the door incorporating a glove system (not shown) known to those skilled in the art.
• a pass through box generally indicated at 12, which box has a front outer door “ (not shown) and an inner lateral door 13.
• a fan chamber 14 which communicates with the internal working region 15 of the cabinet 10 via a HEPA filter 16.
• the work surface 11 of the cabinet 10 is provided at the rear, front and sides with grilles for downward passage of air into a duct 17 which communicates via a " HEPA filter 18 with a recycling duct system generally indicated at 19 which is in communication with the fan chamber 14.
• the grilles are such that the major portion of the air flow into the duct 17 is through the side grilles.
• the fan chamber 14 houses a pair of recycling fans 20 and an exhaust fan 21.
• each pass through box 12 is provided at its top with a filter arrangement comprising a prefilter 22 and a lower HEPA filter 23.
• Each pass through box 12 has a perforated floor 24 under which is a duct 25 communicating with the duct 17 by a bridging or connecting duct 26.
• Air is delivered by the fans 20 through the HEPA_ filter 16 into the work region 15 of the cabinet 10 in a unidirectional downward sterile air flow as a result of which the whole of the worksurface 11 is provided and covered with sterile air. This air then passes into the duct 17 and through the HEPA filter 18 into the recycling duct system 19 back to the fan chamber 14.
• the arrangement of the fans 20 and associated recycling duct system 17, 19 and the fan chamber 14, ensures that the external carcase of the cabinet 10 is held under ' negative pressure to prevent cabinet leaks.
• the cabinet 10 is caused to operate at internal negative pressure by increasing the suction effect of the fan 21.
• the fan 21 is either rendered non- operational or is omitted. In the latter instance, a pre- filter (not shown) for incoming surrounding environmental air may be substituted for the fan 21.
• a negative operational internal pressure, or a neutral operational internal pressure, within the cabinet 10 will involve a negative operational pressure within the pass boxes.
• the pass through boxes 12 operate in a manner known to those skilled in the art and the essential discipline is that only one of the inner and outer doors is open at any one time.
• the inner door 13 of a pass through box 12 is closed and the outer door is open.
• the product is introduced into the pass through box 12 and the outer door is closed.
• a sterilising medium can be introduced into the pass through box 12 with the inner door 13 either open or closed.
• the inner door 13 is then opened and the technician using the glove system transfers the product from the pass through box 12 onto the working surface 11 of the cabinet 10 and the inner door 13 ' is then closed. This sequence of actions is reversed to remove a product from the cabinet 10.
• Mode C shows the condition where the inner door 13 of a pass through box 12 is open and in this instance the sterile vertical air flow passes downwards through the pass through box 12 and is constrained to pass into the duct and recycling systems mentioned above due to the action of the fan 21 and the presence of the main downward sterile air flow in the working region 15.
• Mode D illustrates the condition where pass through box discipline has been breached, i.e. both inner and outer doors open, and in this instance, unfil-tered incoming air through the outer door 27 again passes through the floor 24 of the pass through box 12 into the duct and recycling systems as in mode C.
• An evacuated box ensures that there is no over pressure to contaminate the working region 15 of the cabinet 10. 2) There is a high air change rate which ensures fast cleaning of the pass through boxes 12.
• the perforated floors 24 of the pass through boxes 12 assist in the dissipation of sterilising media from the boxes 12 and it is to be noted that ' these floors are removable for periodic cleaning purposes.
• the inner doors 13 are sloped in order to minimize their intrusion into the work region 15 when open.
• the clean air cabinet of Figs. 1 and 2 can be supplied either in a portable condition or as a fixture and is capable of adaptation for either laboratory recycling or direct exhaust to atmosphere.
• Figs. 3 to 5 illustrate a clean air cabinet in the form of a sterile isolation cabinet made from flexible film.
• the sterile isolation cabinet is generally indicated by the reference 30.
• This cabinet 30 has a glove system (three gloves) generally indicated at 31 and has, in general terms, a turbulent sterile air flow through the working region 32 as can be seen in the left hand side of Figs. 3 and 5.
• a pass through box having only one door (the outer door) is indicated at 33 and at its top it is provided with a HEPA filter 34.
• Mode F shows the condition prevailing when the door of the pass through box 33 is open and in this condition there is an increased loss of air to the laboratory as a result of an increased flow of air into the fan chamber 38 through the pre-filter 42 caused by depressurisation of the canopy 30. This ensures that surrounding environmental air does not enter the open pass box 33.
• the present invention is concerned with providing within the sterile isolation cabinet 30, .which normally has a turbulent sterile air flow, a work area generally indicated at 35 having a unidirectional downward vertical sterile air flow.
• a canopy 36 defining the work area 35.
• the canopy has a back and two side walls which extend almost to the worksurface 37 -of the cabinet 30. It also has a front wall which stops at a higher level to allow access to be gained to the work region 35 by a technician using the glove system 31 and_ this can be clearly seen in Figs. 4 and 5.
• the cabinet 30 above the canopy 36 is provided with a fan chamber 38 incorporating a fan 39 and a delivery duct 40.
• the chamber 38 communicates with the canopy 36 through the intermediary of a HEPA filter 41 in both the E and F modes.
• the working regions 32 and 35 of the cabinet 30 communicate with the fan chamber 38 via a minor section 41A of the HEPA filter 41.
• In mode E air is recycled from the cabinet 30 into the fan chamber 38 where it mixes with incoming external air and is passed back into the working regions 35 and 32 through the HEPA filter 41.
• This aspect of the present invention therefore provides the advantage in a conventional clean air cabinet having a turbulent sterile air flow of a dedicated area of unidirectional downward sterile air flow.
• Fig. 6 illustrates a sterile isolation cabinet 50 identical to cabinet 30 save that it has two pass boxes 51 and 52 and a four glove system 53. identical parts to those in Figs. 3 and 4 have the same references with the suffix "A".
• This sterile isolation cabinet 50 operates in the same way as cabinet 30.
• the clean air cabinet of Figs. 1 and 2 can be made to operate in modes E and F.
• the fan 21 is rendered non-operational or even omitted. In the latter case, it can be replaced by a ' prefilter.
• Mode E operation in this instance, is air flow from working region 15 via ducts 17 and 26 through the perforated floor 24 into the pass box 12 and out of the HEPA filter 18.
• Mode F operation in this instance, is air flow from working region 15 via ducts 17 and 26 through the perforated flow 24 into the pass box 12 and out of the open outer door and possibly the HEPA filter 18. There is also direct air outflow via the open inner and outer doors.
• the clean air room 50 is a flexible film isolator similar to that illustrated in Figs. 3 to 6 which has a generally turbulent sterile air flow with an internal canopy 51 provided a unidirectional downward sterile air flow.
• the canopy is an open-bottom square or rectangular transparent plastics box with the front wall 52 shorter than the back wall 53 and side walls 54 to facilitate access.
• a top HEPA filter 55 covers the air inflow area of both the turbulent air working region and the zoned unidirectional downward air working region defined by the canopy 51.
• Environmental air is sucked into the isolator via a pre-filter 56, a system closure valve 57 and a duct 58 by a fan 59 housed in a fan chamber 60, the air being pushed through the HEPA filter 55 into the aforesaid working regions.
• Air is pulled out or exhausted from the working regions via a HEPA filter 61 by an exhaust fan 62 housed in a fan chamber 63, the latter being connected to an exhaust duct 64 incorporating a system closure valve 65.
• the isolator 50 is provided with one or more pass boxes 68 (only one shown) having an outer door 69 (no inner door) and a top HEPA filter 70.
• Operational mode El corresponds to operational mode E of Fig. 3, and in Fig. 7 it can be seen that there is partial air exhaustion through the HEPA filter 70, the door 69 being closed.
• Operational mode Fl corresponds to operational mode F of Fig. 4, and in Fig. 8 it can be seen that the door 69 is open with increased loss of air to the laboratory, air also being exhausted by the fan 62 and supplied by the fan 59.
• the isolator 50 operates at positive pressure only.
• a fumigation facility may be provided for the isolator 50.
• the system closure valves 57 and 65 serve, inter alia, to close if fan failure occurs.
• one or more pass boxes 81 are provided (only one shown) with inner and outer doors 82, 83 and no top HEPA filter.
• the isolator 80 can operate at either positive or negative pressure.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Clinical Laboratory Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Ventilation (AREA)

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• 1988
  • 1988-11-16 GB GB888826827A patent/GB8826827D0/en active Pending
• 1989
  • 1989-11-16 WO PCT/GB1989/001354 patent/WO1990005549A1/en not_active Application Discontinuation
  • 1989-11-16 EP EP19890912653 patent/EP0444079A1/de not_active Withdrawn

Non-Patent Citations (1)

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