BACKGROUND OF THE INVENTION

This invention is concerned with a system for transferring articles between controlled environments, especially for transporting sterile pharmaceutical products between sterile areas of a manufacturing plant. The system is also suitable for transporting electronic components between clean rooms. For example, goods may need to be transported in sterile conditions between rooms at different locations in a factory through corridors that are maintained at a lower category of sterility or cleanliness. As the products leave and enter the rooms, there must be a minimal transfer of air into the room from the corridor.

In an existing system, for example as described in EP-A- 0586307, products are transported manually in sealed containers . A closed circular port on the container is engaged via a bayonet fitting with a corresponding closed port in the wall of a sterile area. The doors of the two ports are locked together. The wall port can be then be opened from inside the sterile area, simultaneously removing the door of the container port. This allows access to the interior of the container from the sterile area, so that the contents of the container can be removed. The ports are engaged, by a rotary movement of the bayonet connections, bringing profiled seals into contact, to prevent the external atmosphere penetrating the sterile room. The rotary engagement between the bayonet fittings and the seals may result in abrasion and the risk of generating particles that will contaminate the product. Also the profiled seals are difficult to clean, and the system has a low capacity, because of the need for manual handling.

SUMMARY OF THE INVENTION

The present invention provides a system with improved sealing arrangements that avoid rotary contact and abrasion and also offer more secure sealing. Further, the system is capable of offering high capacity transfers, and is susceptible to mechanisation and automated control .

According to the present invention there is provided a system for use in the transfer of articles between atmosphere- regulated environments, comprising :

(i) a transfer container having a removable door giving access to the container and sealing means to provide an airtight seal between the container and its door,

(ii) a door frame for insertion in the wall of an atmosphere-regulated environment,

(iii) a door for insertion in the door frame, having sealing means to provide an airtight seal between the door and the frame, the container and/or the frame having means for latching the container to the frame so that the container door and wall door are juxtaposed, and means for forming an airtight seal between the container and the frame, the container door and/or the wall door having means for latching the container door to the wall door, and sealing means to isolate the air space formed between the container and wall doors when latched together, characterised in that the seals between the door frame and the wall door and between the door frame and the transfer container are expandable seals, the seal between the wall door and the container door is an expandable seal or a compressible seal, and the seal between the container door and the container is a compressible seal.

Preferably the seals between the door frame and the wall door, between the door frame and the transfer container, and between the wall door and the container door are all expandable seals, since they may all be located on the door frame or wall door,

from which they can receive air and electricity services from within the sterile room. The seal between the container and its door is more conveniently a compressible seal, since this avoids the need to provide a power source within the container.

The various latching means may be located on only one of the members to be engaged, if for example friction clamps are used However for secure latching, a latching member will preferably be provided on each surface for interlocking engagement, typically between a static member on one component and a moving member on the other component.

The container may be dimensioned so that it can be carried manually between the regulated environments, but more suitably, for efficient load transfer it will be of a size that will be transported on a sledge or trolley, so that it may be pushed or driven. Most conveniently the container will be mounted on its own wheeled chassis.

Typically the door frame has peripheral frame members defining a central door aperture, and the door is located in the aperture, and the door frame has a first expandable seal extending around the aperture to seal against the door and a second expandable seal extending around the aperture to seal against a transfer wagon brought into a docking relationship with the door, and has means for latching to the transfer wagon, and the door has means for latching to the door of the transfer wagon, and a third expandable seal extending around its periphery to seal against the wagon door to isolate the airspace between the doors when latched.

The transfer wagon may be a wheeled chamber having an access aperture closed by a hingeless door, means releasably holding the door against a peripheral compressible seal extending around the aperture, means on the door for latching with the door in the wall of a regulated environment, and means on the container for latching to the frame containing the wall door.

In another aspect the present invention provides a process for transferring articles between controlled atmospheres, in which a wagon with a hingeless door is secured to a wall of a controlled atmosphere room so that the wagon door is opposed to a door in the wall and an expandable seal in the frame of the wall door is inflated to form a seal between the wagon and the wall to isolate the opposed doors from the external atmosphere, and the wagon door is latched to the wall door, and an expandable seal around the periphery of the wall door is inflated to contact the wagon door to isolate the air trapped between the doors, whereby the wall door may be opened into the room, thereby removing the hingeless door from the container and allowing articles to be transferred from the room to the container, and vice versa.

In a further aspect the present invention provides a process for transferring articles between atmosphere-regulated environments, comprising: a. providing :

(i) a transfer container having a removable door giving access to the container and sealing means to provide an airtight seal between the container and its door,

(ii) in the wall of an atmosphere-regulated environment, a frame defining an aperture, the frame having first inflatable sealing means to provide an airtight seal between the frame and a door located in the aperture, means for latching the container to the frame so that the container door and wall door are juxtaposed, second inflatable sealing means forming an airtight seal between the container and the frame,

(ii) on the wall door and /or the container door, means for latching the container door to the wall door and sealing means to isolate the air space between the latched container and wall doors, b. bringing the transfer container to the wall door, c. latching the container to the wall door frame and inflating the first inflatable sealing seams so as to form an

airtight seal between the container and the frame and isolate the doors from the external atmosphere, d. latching the container door to the wall door so that the sealing means isolates the air space between the latched container and wall doors, e. releasing the second inflatable sealing means between the frame and the wall door and opening the wall door into the regulated environment so as to remove the latched container door from the container, f. passing articles from the regulated environment through the wall aperture into the container, g. closing the wall door to locate the latched container door with its sealing means and inflating the second inflatable sealing means to reseal the wall door to the frame, h. unlatching the container door from the wall door and releasing the seal between the doors, i. releasing the first inflatable sealing seams between the frame and the container and unlatching the container from the frame.

Subsequently the process comprises : j . transporting the container to a second regulated environment, k. repeating steps c to f of above at a second wall and a second wall door so that the container is in communication with the second regulated environment, and

1. transferring articles from the container into the second regulated environment.

Further features and advantages of the invention will become apparent from the following detailed description of a preferred embodiment of the invention.

BRIΞ? DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view showing the general arrangement of a transfer wagon and wall door in accordance with the invention.

Figure 2 is a schematic plan view of a corridor showing potential wagon movements.

Figure 3 is a horizontal cross section showing the wagon docked with the wall door.

Figure 4 is an enlarged cross-section through the lateral block that latches the wagon to the door frame.

Figure 5 is schematic cutaway view (not to scale) of the wagon door and wall door showing locking members securing the wagon door and the wall door.

Figure 6 is partial cross section through the wall door showing the mechanism for latching the doors.

Figure 7 is a frontal elevation of the wagon showing an external cylinder for initiating release of the wagon door and the mechanism for securing the wagon door.

Figure 8 is a partial cross section through the wagon showing the mechanism for securing the wagon door.

Figure 8a is a partial external view of the section shown in the preceding Figure.

Figure 9 is an enlarged cross section showing the arrangement of the seals when the wagon is docked with the wall door frame.

Figure 10 is a horizontal cross section as in Figure 3 but showing interlocked wagon and wall doors opening into the sterile room.

DETAILED DESCRIPTION

Referring to Figure 1 of the drawings, a wall 1 separates a sterile room from an area maintained at a lower level of cleanliness, such as a service corridor. Mounted in the wall is a stainless steel frame 2 with a central aperture closed by a door 3 which allows access into the sterile room. Products for use in the sterile room are transported to the wall door 3 in a wagon 4 comprising a stainless steel transfer container body 5 sealed with a door 6. A glass panel 60 allows the interior of the container to be inspected. To maximise the load that can be carried, the container is mounted on a chassis 7 with castor wheels for easy movement. Lateral grab bars 8 assist staff to manoeuvre the wagon to dock with the door 3.

In brief, the operation of the system is that the wagon is manoeuvred so the wagon door is face to face with the wall door. The wagon is locked to the door frame by bolts in lateral guide blocks 9 secured to the door frame, and at the same time latches 10 in the wall door engage with rods 11 mounted over recesses 12 in the wagon door. Seals in the wall door frame 2 and wall door 3 contact the wagon body 5 and wagon door 6 respectively to isolate the latched doors 3 , 6 from the surrounding atmosphere. An upright cylinder 13 secured to the base of the wall door frame 2 forces out a piston 14 to actuate a mechanism in the wagon body 4 to release the wagon door 6. The wall door 3 may then be opened into the sterile room carrying the wagon door 6 with it. Personnel in the sterile room can then load products into the interior of the wagon body 5 or remove its contents, without allowing the atmosphere of the sterile room to be contaminated by the atmosphere of the area in which the wagon 4 is operating. Reversing the above sequences allows the wagon 4 to be undocked from the wall door frame 2 for movement to another area.

Possible wagon movements are shown in Figure 2, where sterile production areas A, B, C are self-contained and isolated from each other, and are maintained at a high classification of cleanliness. The areas A, B, C all have docking ports in the form of wall frame/door systems as described above, giving access to a service corridor D, which can be maintained at a lower cleanliness classification than the production areas. The production area could for example be an area A in which vaccines are filled into vials, and areas B and C containing freeze dryers for processing the filled vials. Therefore, using the service corridor, products may be transported between the production areas A, B, C via the corridor D using the transfer wagon described above, without endangering the integrity of the production areas or continuity of the transferred products. In Figure 2, a wagon is shown docked with a wall frame of area A but with both doors closed. In area B the wall door is closed and a sealed wagon approaches

for docking. At area C, a wagon has been docked with wall frame, and after appropriate latching and sealing, the wall door has been opened into area C, at the same time removing the wagon door and allowing access to the interior of the wagon from the sterile area C. Alternatively, the wagons can be moved to a holding area or cold area at the end of the corridor. Here the wagons can be maintained at a desirable low temperature and, if necessary connected to a power supply to run internal fans, all while securely sealed.

The structure and operation of the system will now be described in more detail, referring firstly to Figure 3. The door frame members 2 are of hollow stainless steel construction and are flush with the surface of the wall 1. The hollow construction allows compressed air ducting and electrical wiring services to be carried to seals and other components mounted on the frame 2. The wall door 3 is located within the aperture defined by the door frame 2. The wall door 3 is hollow to contain a mechanism for latching to the wagon door and seals to contact the wagon door. Compressed air and electrical services are conveyed into the door 3 through hollow hinge bars 15 positioned near the top and bottom of the door 3 and attached to the door frame 2. The offset mounting of the hinge arms 15 allows the wall door 3 to be swung well clear of the door aperture to give access to a docked wagon 4. The wall door 3 is sealed to its door frame 2 by an inflatable silicone rubber seal 16 extending around the periphery of the door frame 2 and located in a recess in the frame . The hollow door 3 has a depth that occupies only part of the thickness of the wall 1, leaving a recessed area in front of the wall door 3 in which the front surface of the wagon 4 can be inserted during docking. This arrangement allows a further inflatable seal 17 to be located in a second peripheral recess in the door frame 2, beyond the front surface of the wall door 3, where it can be inflated to contact the side surface of the wagon body 5 when docked. The position of the seals is shown in more detail in Fig. 9.

The front surface of the wagon body 5 is preferably configured with a peripheral rebate 18 around the wagon door 6 so that the door 6 itself is mounted on a projecting island that mates with the recessed area in front of the wall door 3. The rebate 18 on the wagon front surface is dimensioned so that when the rebate 18 contacts the door frame 2, the wagon door 6 is optimally positioned relative to the wall door 3, but not in contact with the wall door 3. Thus any physical shocks during the docking procedure are absorbed by the wall door frame 2 or the wagon structural elements and not by respective doors 3, 6.

Referring also to Fig. 7, the body or ^' container portion 5 of the wagon 4 is constructed from stainless steel with a hollow external frame 19 defining an internal cavity, which contains posts 20 with support elements for shelves or to receive directly trays containing pharmaceutical products such as vials or syringes. The frame 19 is provided with ducting to provide a laminar air flow across the shelved products . An electrically powered fan is located in the base of the frame and circulates air across the internal cavity and shelved products through a laterally positioned supply filter 21 and exhaust filter 22. The power for the fan may be provided by on-board batteries, or through a power lead 45 connected to the electrical supply in the wall door frame 2 (see Fig. 1) .

When docking the wagon 4 with the wall door 3 , ^• the front surface of the wagon is guided into position by inclined surfaces 23 on the lateral blocks attached to the door frame 2. As shown in Figure 4, the lateral blocks 9 contain a protruding bolt 24 which is biased by a spring 25 into the protruding position. When the wagon moves into the docking position an inclined abutment block 26, secured to each side surface of the wagon, engages the inclined end surface 27 of the protruding bolt and pushes it to one side, allowing the abutment block 26 to pass the bolt position. As the wagon reaches the docking position, the end surface of. the abutment block 26 passes the edge of the bolt 24, which springs back into position so as to

lock the wagon in the docked position. A sensor 28 checks that the abutment block 26 is in the locked position, so confirming that the wagon is in the docked position. A further sensor 29 checks that the bolt is in the locked position. The protruding portion of the wagon front surface is now within the recessed area in front of the wall door 3. The seal 17 in the recessed area in front of the wall door 3 is then inflated to contact the wagon side surface and isolate the opposed doors 3 , 6 from the corridor atmosphere. The power lead 45 trailing from the door frame 2 is connected to an electric socket on the wagon body 5. The electrical supply powers the on-board fan to maintain an overpressure in the wagon during the docking procedure (or to charge on-board batteries) .

The wagon door 3 is a single sheet of stainless steel clamped to the front peripheral surface of the wagon body 5 to compress a tubular silicone rubber seal 30 secured to the front surface with a silicone adhesive. The steel plate is mounted on a rigid frame 31. Four apertures in the steel plate, positioned towards the corners of the door 6, open into recesses 12 secured to the door frame 31. The apertures are spanned by horizontal locking bars 11. Protruding from the wall door 3 towards each recess 12 are four locking arms 10 with hooked end portions which are pivoted within the door to allow vertical movement. The locking arms 10 are spring biased into the horizontal position, as shown in Figs. 5 and 6. As docking takes place, the arms 10 come into contact with the locking bars 11 on the wagon door. The inclined front surface of each locking arm 10 rides up over its opposed bar 11, moving into the recess 12 behind the bar 11. At the optimum docking position the hooked end portion of the locking arm 10 drops behind the bar 11 under the influence of the biassing spring to lock the wall door 3 to the wagon door 4. A sensor detects that the position of the locking arms 10 is such that the hook portion is in the locking position. While the upper locking arms are lifted upwardly and fall behind the locking bars, the lower locking arms are preferably positioned in the opposite

sense, so they are pushed below their co-operating bars and rise to the locking position. This opposed gripping action provides the optimum clamping effect.

When the sensors confirm the presence of the wagon 4 in front of the wall door 3 and the clamping of the doors 3, 6 to each other, an inflatable seal 32 located in a peripheral recess in the wall door 3 is inflated to seal against the wagon door 6 (see particularly Fig. 9) . This isolates a portion of corridor air that was trapped between the doors 3, 6 on inflation of the frame to wagon seal 17.

The wagon door 6 is hingeless and is secured to the wagon body by clamps so that the door 6 compresses the tubular seal 30 and seals the interior cavity of the wagon. When the wagon 4 is sealed to the door frame 2 by seal 17, and the two doors 3, 6 are clamped together, the wagon door can be released from its clamps . The piston 14 in the cylinder 13 attached to the base of the door frame in the corridor is raised by compressed air supplied through the door frame. As shown in Figs. 7 and 8, the piston 14 engages a short lever 33 mounted on the end of a rotatable bar 34 passing across the base of the wagon body in the hollow frame 19. The rotary movement caused by the piston 14 lifting the lever 33 is transmitted by pivotable levers 35 on each end of the base bar 34 through rods 36a,b and levers 37a,b, positioned vertically in the hollow frame of' the wagon body, to rotate clamping eccentrics 38. The eccentrics have part-circular surfaces that engage circular studs 39 mounted on pins extending laterally adjacent each corner of the rigid frame 31 of the wagon door 6. The raised piston 14 maintains the eccentrics 38 in the undamped position against spring pressure biassing the eccentrics 38 into the clamping position. A sensor confirms the piston position. The rotating of the eccentrics 38 so that the part-circular portion lies behind the circular studs 39 means that the wagon door 6 is free to be pulled away from the wagon body 5.

With confirmation of the correct positioning of the clamps 10, 38 and seals 17, 32, the inflatable seal 16 between the wall door 3 and its frame 2 is deflated. The wall door 3 can then be pulled away from its frame 2 and swung into the sterile room, carrying the wagon door 6 with it as shown in Figure 10. It can be seen that the only risk of contamination arises from the corridor air trapped in the small volume defined between the seals 16, 17, 30, 32. If desired this could be purged by sterile air or inert gas, or air containing a sterilising agent. Alternatively a device could be positioned on the frame 2 above the wall door 3 to provide a laminar flow of sterile air across the wall door 3 as docking takes place. However, in practice, with appropriate positioning of the seals 16, 17, 30, 32 to minimise the volume between the seals, the amount of corridor air that is transferred to the sterile room is within acceptable limits.

After emptying or loading or reloading the wagon body 5 through the central aperture in the door frame 2, the combined doors 3 , 6 are swung back into position so that the rear surface of the wagon door 3 compresses the tubular seal 30. When sensors note that the combined doors are in place within the door frame 2, the inner peripheral seal 16 is inflated to seal the frame 2 against the wall door 3 and isolate the wagon from the sterile room.

Then pressure is released from the pneumatic cylinder 13 at the base of the door frame 2 outside the sterile room to withdraw the piston 14. This allows the rods and levers 36,37 within the container frame to move under the pressure of the internal springs to re-engage the part circular portions of the eccentrics 38 in front of the circular studs 39 mounted on each corner of the support frame 31 of the wagon door 6. When it is confirmed by sensors that the piston 14 has been returned to its housing, so that the wagon door 6 is engaged with the container frame, the seal 32 in the peripheral recess on the wall door 3 is deflated to break the seal between the two doors

3, 6. Actuation of pneumatic cylinders 40 within the wall door moves rods 41 to make the locking arms 10 move out of engagement with the locking bars 11 on the wagon door 6, against the biasing spring pressure. When position sensors on the mechanism confirm that the locking arms 10 are disengaged, the outer peripheral ^' seal 17 in the wall frame 2 is deflated, breaking the seal between the wagon body 5 and the door frame 2. The bolts 24 in the lateral blocks 9 are then withdrawn under pneumatic pressure. As seen from Fig. 4, a piston 42 within the lateral guide block 9 pushes arm 43 secured to each bolt 24 to move them against the action of the biasing springs 25. After disengaging the electrical connecting cord 45 which provides power to the wagon systems, the wagon 4 can then be wheeled away from the wall door 3. Releasing pneumatic pressure in the wall door cylinders 40 and the piston 42 allows the biasing springs to return the bolt 25 and locking arms 10 to their rest position, ready for engagement with another wagon.

The use of sensors to detect that appropriate components are in place before operating any of the seals or locking devices means that the docking procedure is susceptible to automation and control by a PLC (programmable logic controller) system. The sensors may rely on magnetic induction, operation of reed switches, or light detection, depending on their location. The operation of the electrical systems may also be monitored by a computer system to log and control movements of wagons to different doors. This can be coupled with a system for identifying each wagon so that the docking procedure can be initiated only if the wagon is programmed to give the correct identification appropriate to the room to which access is required.

Alternatively, a simple mechanical identification system can be provided by locating shaped blocks on the front surface of the wagon. The shaped blocks must be mated with an appropriately shaped aperture in a template mounted over the wall door before

the wagon can approach the wall doors closely enough to activate the position sensors.

As the system described above ^' is intended for use in a sterile pharmaceutical environment, it is manufactured from stainless steel and silicone rubber, and structured to allow easy removal of broken products and easy cleaning. This means that all areas to be cleaned are formed with rounded corners and with no inaccessible recesses. All tray racks need to be removable for cleaning and to provide full access to the internal cavity of the transfer container. Equally, the filters must be removable for cleaning and the air ducts accessible for cleaning after removal of the filters.

The embodiment shown has been designed to carry two stacks of trays which are loaded between the ergonomic height limits of 60 and 150 centimetres from the ground. The laminar flow across the products within the chamber is typically at an air flow velocity of around 0.2 meters per second through HEPA filters on the supply and extraction sides. When the fan is in operation an internal over-pressure (relative to the corridor) of 15 pascals is desirable, which may be monitored by an external meter display. If on-board batteries are provided, a laminar flow of air can be maintained at all times within the wagon.

For pharmaceutical use the internal temperature is preferably kept at around 4°C and this may be monitored by a temperature display outside the wagon. If the wagon is provided with an on¬ board power system, then it may be possible to provide an onboard cooling system to control the temperature. Otherwise, the external temperature display may be used to advise the operator when the wagon needs to be moved to a cold area to maintain the temperature.

INDUSTRIAL UTILITY

The invention has been illustrated above by reference to the handling of sterile pharmaceutical products. It will be recognised that similar procedures and apparatus will find use in any situations where secure transfer between regulated environments is needed. For example, apparatus within the scope of this invention may be used for moving silicone wafers or printed circuit boards between clean rooms, or moving photo masks or printing plates between clean rooms or dark rooms (or "yellow" rooms) .