The present invention relates to an assembly for loading or unloading a freeze dryer or the like.
Freeze dryers typically incorporate a pressure vessel having a freeze drying chamber for receiving a plurality of containers or vials typically containing sterile material to be freeze dried. Access to the chamber for automated loading and removal of vials is through a rectangular opening, or slot, formed in a wall or in the main door of the chamber. The slot is closed by a slot door which, with the chamber, forms a vacuum seal around the slot.
To enable vials to be inserted into the chamber, the slot door is vertically raised relative to the slot by moving the slot door along guide tracks. A loading mechanism provided opposite the slot door pushes vials from a conveyor on to a shelf of the chamber. The vials may be loaded row by row on to a shelf, a number of rows at a time, or a complete shelf full at a time. The loading mechanism is subsequently withdrawn and the slot door closed to enable the contents of the vials to be freeze dried. The vials can be subsequently removed from the chamber, typically in the same manner (row by row or shelf by shelf) as they were loaded into the chamber, using an unloading mechanism.
Pharmaceutical freeze dryers are usually at least partially housed in a clean room, with the loading and unloading mechanism being located in a sterile environment, for example an isolator, adjacent the clean room environment. The size of these loading and unloading mechanisms can contribute greatly to the overall size of the foot-print of the freeze dryer. As the cost of maintaining the sterile environment generally increases with size, conventional loading and unloading mechanisms, typically requiring around 2 m2 and 1 m2 of floor space respectively, can significantly increase running costs.
An embodiment of the present invention is to provide a mechanism for loading or unloading a freeze dryer which can significantly reduce the size of the overall foot-print of the freeze dryer.
In a first aspect, the present invention provides an assembly for loading vials into or unloading vials from a chamber of a freeze dryer or the like, the assembly comprising a bar for engaging vials, and means for effecting lateral movement of the bar, characterised in that, in a retracted position of the bar, at least part of the moving means is wound around a wheel, the assembly comprising drive means for rotating the wheel to unwind the moving means from the wheel and effect the movement of the bar.
As used herein, the term “wheel” connotes any structure rotatable about an axis.
The invention can thus provide a compact assembly for unloading vials from, or loading vials into, a chamber of a freeze dryer, which can significantly reduce the overall size of the foot-print of the freeze dryer.
In order to provide a compact assembly, a greater proportion of the moving means is wound around the wheel in the retracted position of the bar than in an extended position of the bar. In the retracted position, the moving means is preferably wound at least 180° around the wheel, more preferably at least 270° around the wheel.
Said at least part of the moving means preferably comprises a chain or other plurality of linked members wound about the wheel, the chain being attached to a pusher head for engaging the bar. In the preferred embodiment, the linked members are hinged together, and are in the form of tubular members hinged at each end thereof to a respective adjacent tubular member. With this structure, wires or the like for supplying control signals to the drive means for the wheel can be conveniently passed through the tubular members. The wheel is preferably in the form of a sprocket, having a plurality of radially extending teeth profiled to receive the hinges of the chain.
The assembly preferably comprises guide means for guiding the moving means during rotation of the sprocket. The guide means may be arranged to align the members of the chain relative to the bar, for example, orthogonally thereto, as they are unwound from the sprocket. The guide means may comprise a guide track extending about at least part of the sprocket, the chain carrying a plurality of rollers for engaging the guide track. For example, a roller may be provided at or towards one end of each tubular member.
In order to isolate the sprocket and drive means from the sterile environment of an isolator or the like, the sprocket and drive means are preferably located within a housing having an opening through which the moving means passes during rotation of the wheel. Bellows or the like may be provided to isolate the chain from the ambient atmosphere as it passes through the opening with rotation of the sprocket. These bellows may be conveniently formed from plastics material.
The present invention also provides a freeze dryer comprising a chamber and at least one assembly as aforementioned. One assembly may be provided on one side of the chamber for loading vials into the chamber, and another assembly may be provided on the other side of the chamber for unloading vials from the chamber.
Preferred features of the present invention will now be described with reference to the accompanying drawings, in which:
a) and (b) illustrate respective arrangements of vials prepared for loading into the freeze dryer of
With reference to
An assembly for loading and unloading the chamber 12 is formed from several modules supported by a supporting frame located in an isolator cabinet 18. The assembly enables automated loading of the freeze dryer 10 with vials received from a filling machine, and automated unloading of those vials from the freeze dryer for subsequent conveyance to a capping machine.
The supporting frame is bolted to the frame of the freeze dryer 10, and to the floor of the isolator. The supporting frame is formed from strong stainless steel plates. Within the isolator 18, the external surfaces of the supporting frame and the modules of the assembly for loading and unloading the chamber are designed so as to be readily accessible for cleaning and sterilising in situ using, for example, vaporised hydrogen peroxide.
The modules of the assembly for loading and unloading the chamber 12 will now be described.
An in-feed conveyor 20 collects the vials coming from a filling machine (not shown) located outside the isolator and conveys the vials to an in-feed star wheel 22 mounted on the supporting frame. Appropriate guiding ensures a smooth transition between the in-feed conveyor 20 and the in-feed star wheel 22 with correct feeding of the in-feed star wheel 22. For small vials subject to tipping, a mechanical reject system may be provided upstream from the in-feed star wheel 22 to reject fallen vials. The in-feed conveyor 20 is driven by a motor located beneath the supporting frame.
The in-feed star wheel 22 serves to position the vials received from the in-feed conveyor on to a pusher conveyor 24. The in-feed star wheel 22 and the pusher conveyor 24 are driven by respective servomotors located beneath the supporting frame. The rotational speed of the in-feed star wheel 22 can be synchronised with the speed of the pusher conveyor 24. Control of the starting, acceleration, deceleration and stopping of the in-feed star wheel 22 relative to the pusher conveyor 24 can be used to convey the required number of vials on to the pusher conveyor 24 and to control the pitch of those vials.
A loading pusher 26 pushes vials from the pusher conveyor 24 on to an accumulation table 28. As shown in
With reference to
A motor is provided for rotating the sprocket 106, the sprocket 106 and motor being contained within a housing 118 having an opening 120 through the pusher head 100 protrudes when the mechanism 34 is in the retracted position shown in
The mechanism 34 is also provided with guides for guiding both the pusher head 100 and the tubular members 104 as the sprocket 106 is rotated. This can ensure that the mechanism 34 is correctly aligned relative to the pusher bar 32 as the pusher bar 32 is moved into the chamber 12. The guides comprise rollers 124 for guiding initially the pusher head 100 and then the tubular members 104 as they unwound from the sprocket 106, and a guide track 126 extending, as shown in
A number of sensors 130 are also provided for detecting that the mechanism is in one of a home position, a fully extended position and a fully retracted position, by sensing the presence of detection points provided on the sprocket 106.
Returning to
As shown in
The bridge plate 38 is located between the accumulation table 28 and the intermediate plate 40. The bridge plate 38 can be rotated from the stowed, raised position shown in
The free ends of the ribbons 46, 48 of each reel assembly 44 are connected to the transfer bar 42 via a connecting member 62 attached to the transfer bar 42 and extending substantially orthogonal therefrom. The free end of the lower ribbon 48 is rigidly attached to a first linking member 64, the first linking member 64 being pivotally attached to the connecting member 62 via pivot 66. The free end of the upper ribbon 46 is rigidly attached to a second linking member 68. The second linking member 68 is pivotally attached to a linking arm 70 via pivot 72, the linking arm being in turn pivotally attached to the connecting member 62 via pivot 74.
Movement of the first and second linking members 68, 64 as the coils are unwound from the drums is guided by guide members 76, 78, 80, 82 located on each side of the transfer bar 42. Each guide member comprises upper and lower slots, movement of the first linking member 68, and thus the free end of the upper ribbon 46, being guided by the upper slots and the movement of the second linking member 64, and thus the free end of the lower ribbon 48, being guided by the lower slots. Guide members 76 are attached to the sides of the accumulation table 28, guide members 78 are attached to the sides of the bridge plate 38, and guide members 80 are attached to the sides of the intermediate plate 40. Guide members 82 are moveable between a stowed position, shown in
The drive shafts 58 of the reel assemblies 44 are connected to a common servomotor located beneath the supporting frame 18. Each drive shaft 58 is connected directly to the upper drum 50 of the respective reel assembly 44, the drums 50, 52 being configured such that rotation of the upper drum 50 causes both drums 50, 52 of the assembly 44 to be rotated synchronously. This enables the upper and lower ribbons 46, 48 to be simultaneously unwound from, or wound on to, the drums 50, 52 to move the transfer bar 42 into, or out from, the chamber 12 as required. The lower drum 52 can also be rotated independently from the upper drum, for example, by short stroke air cylinders provided beneath the supporting frame 18, to effect lowering and raising of the transfer bar 42.
Returning now to
A typical sequence for loading the chamber 12 using the assembly shown in
First, the slot door 16 is raised to allow vials to be inserted into the chamber 12 through the slot formed in the chamber wall. The bridge plate 38 is rotated from the raised position shown in
Vials from the filling line arrive on the in-feed conveyor 20, which acts as a buffer. When a sensor detects that the number of vials in the buffer is sufficient, the in-feed star wheel 22 transports the required number of vials to the synchronized pusher conveyor 24. This mechanism eliminates the linear errors caused by diametrical tolerance of the vials. The sprocket 106 is rotated anticlockwise to cause the pusher bar 32 to push the complete row of vials forward against the previous row of vials (if any) on the accumulation plate 28, and push the whole pack forwards by the equivalent of one vial diameter. The sprocket 106 is then rotated clockwise to withdraw the pusher bar 32 ready to push forward the next row of vials. When sufficient rows of vials to fill a shelf 14 have been assembled, the sprocket 106 is rotated anticlockwise to cause the pusher bar 32 to push the pack clear of the accumulation plate 28 and the bridge plate 38 and position the pack on the shelf 14. Alternatively, for cold shelf filling, the vials may be pushed row by row on to the shelf 14, or a number of rows of vials may be pushed at a time on to the shelf 14.
After retraction of the pusher bar 32, the moveable guide members 82 are raised and the bridge plate 38 is rotated to enable the freeze dryer to position the next empty shelf for loading. While the shelf is being positioned the next rows of vials are being assembled.
The sequence is repeated until the last shelf to be loaded. When all of the shelves have been loaded with vials, the moveable guide members 82 are raised, the intermediate plate 40 is retracted, the bridge plate 38 is raised and the slot door 16 is closed.
In the embodiment described above, the transfer bar 42 is used to subsequently unload the vials from the chamber 12. In a second embodiment shown in
A typical sequence for unloading the chamber 12 using the assembly shown in
In summary, a freeze dryer comprises a chamber having a rectangular slot through which vials are inserted into the chamber. An assembly for loading the chamber comprises a bar extending across the slot to engage vials to be inserted into the chamber. The bar is attached to a mechanism for moving the bar laterally into and out from the chamber. In a retracted position of the bar, at least part of the mechanism is wound around a sprocket. Rotation of the sprocket unwinds the mechanism to move the bar into the chamber.
While the forgoing description and drawings represent the preferred embodiments of the present invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the true spirit and scope of the present invention.
Number | Date | Country | Kind |
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0413115.7 | Jun 2004 | GB | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/GB2005/002209 | 6/6/2005 | WO | 00 | 9/24/2007 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2005/121672 | 12/22/2005 | WO | A |
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Number | Date | Country | |
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20080134537 A1 | Jun 2008 | US |