GB2500639A

GB2500639A - Method and apparatus for sealing an array of tubes

Info

Publication number: GB2500639A
Application number: GB1205437.5A
Authority: GB
Inventors: Justin Michael Owen
Original assignee: Tap Biosystems PHC Ltd
Current assignee: Tap Biosystems PHC Ltd
Priority date: 2012-03-28
Filing date: 2012-03-28
Publication date: 2013-10-02
Also published as: GB201205437D0

Abstract

An apparatus (10) for sealing an array of tubes 42 comprises a rack support 30 for supporting the array of tubes with their upper rims 43 disposed in a horizontal plane, an anvil plate (200; fig4) having an array of holes (206) for placement over the tubes 42, a punch station 60 comprising a punch tool (62; fig 9) having a column of punch pins (66; fig 9), a sealing station 70 comprising a sealing tool (72; fig 9) having a column of heated pins (76; fig 9) and a sealing membrane transport mechanism for delivering sealing material to the punch station. The membrane is disposed between the punch pins and the anvil plate with the punch pins configured to pierce through a membrane so as to separate individual discs from the membrane to overlie associated tube rims. The heated pins are configured to pass from above into the through holes to apply heat to the individual discs to seal the discs to the rims of the tubes. The punch tool has multiple punch pins and the sealing tool has multiple heated pin arranged in a linear array corresponding to a column of the array of tubes. A method of operating the apparatus is also disclosed.

Description

I

METHOD AND APPARATUS FOR SEALING AN ARRAY OF TUBES

Field of the Invention

The present invention relates generally to the sealing of tubes and, in particular, to sealing small tubes within large arrays.

Background to the Invention

In biological and chemical assay processes and systems which operate with tubes containing samples of biological or chemical material it is important that the contents of the tubes remain isolated from the atmosphere in the lab and during storage so that the contents do not evaporate or become contaminated with foreign bodies. Therefore, it is common practice to seal tubes. This may be performed with a sealing membrane that, once punctured must be replaced, or it may be with a resealable membrane.

When the samples contained within the tubes are not subjected to frequent access, then a sealing membrane that is not resealable is sufficient. The sealing membrane may take the form of a foil, backed with an adhesive that may be heat or pressure sensitive. In order to apply such a sealing membrane to a tube, it is usual to bring the top of the tube into contact with a sealing membrane that has been treated with such an adhesive and then to apply heat or pressure, as applicable, to cause the adhesive to adhere to the top of the tube. In general it is often necessary to seal a large number of tubes at the same time and therefore the sealing membrane is applied to an array of tubes that are localised in a supporting storage rack. However, the racks in which the tubes are placed are designed to make the most economical use of space possible and therefore the upper rims at the tops of the tubes are often in close contact. Very accurate registration and positioning of the tubes is essential.

As technology advances it is possible to process smaller samples and therefore there is a growing demand for smaller tubes, exacerbating these problems. This has led to the situation where it is difficult to seal and separate a large number of very small tubes held in a rack.

In order to separate the sealed tubes in such close contact it has been found to be necessary to use an array of spring-loaded pins arranged beneath the storage rack for pressing a number of the tubes out of the rack into contact with a sealing membrane disposed above the plate, a hot platen relatively movable into contact with the sealing membrane to melt the sealing membrane to the tops of the tubes that have been raised from the rack by the pins, and a die plate with holes movable relatively past the tops of the newly sealed tubes in order to cut the sealing membrane around each tube and thus separate the sealed tubes from the remainder of the sealing membrane.

In order for there to be enough scrap sealing membrane left for it to remain intact with sufficient strength to be easily removed from the device without disintegration after the sealing and separation steps, the pins may be actuated to raise the tubes from the rack in a checkerboard pattern. This facilitates the use of the sealing membrane in the form of a continuous web that can be fed from a reel into the apparatus with the resultant scrap sealing membrane being wound onto a second reel.

Such automation of the sealing and separation of large arrays of small tubes requires relatively complex equipment, and in particular requires complex, moving, precision parts to be located both above and below a rack holding the array of tubes.

The use of a checkerboard pattern also results in a significant proportion of the continuous web of sealing membrane being wasted.

Accordingly, it is an object of the invention to provide a simplified apparatus and associated method for sealing tubes within large arrays. Another object of the invention is the reduction of waste sealing membrane.

Summary of the Invention

According to a first aspect of the invention, there is provided an apparatus for sealing an array of tubes and for separating individual tubes from the sealed array, the apparatus comprising: a rack support for supporting an array of tubes within a storage rack within the apparatus, wherein upper rims of the tubes are disposed in a plane; an anvil plate having upper and lower surfaces and an array of through holes corresponding to the array of tubes, the anvil plate being placed on the array of tubes in a placement position in which the lower surface of the anvil plate is below the plane and the upper surface of the anvil plate remains above the plane; a punch station comprising a punch tool having an array of punch pins each having a cutting edge, wherein the punch tool is moveable relative to the rack support to a position in which the array of punch pins is brought into registration with a corresponding array of the holes through the anvil plate, and wherein the cutting edges are moveable perpendicular to the plane relative to the rack support between a position above the plane and a position below the upper surface of the anvil plate; a sealing station comprising a sealing tool having an array of heated pins each having a lower surface, wherein the sealing tool is moveable relative to the rack support to a position in which the array of heated pins is brought into registration with a corresponding array of the holes through the anvil plate, and wherein the lower surfaces of the heated pins are moveable perpendicular to the plane relative to the rack support between a position above the plane and a position in the through holes substantially aligned with the plane; and a sealing membrane transport mechanism for supplying a web of sealing membrane to the punch station, whereby at least a portion of the web of sealing membrane is disposed between the cutting edges of the punch pins and the upper surface of the anvil plate; wherein the relative movement of the cutting edges and the rack support punches respective portions of the sealing membrane to overlie the associated tube rims; and wherein the relative movement of the lower surfaces of the heated pins and the rack support seals the respective punched portions of the sealing membrane overlying the associated tube rims to those tube rims.

As described above, in the prior art, arrays of tubes have typically been sealed and then separated, with apparatus requiring hardware operative both from above and from below the array of tubes. By first placing an anvil plate over the array of tubes, the actions can be reversed -first cutting individual portions from the sealing membrane to overlie associated tube rims, and then sealing those individual portions to the associated tube rims. This results in a vastly reduced waste of the sealing membrane. This also obviates the need to separate the individual tubes from the sealing membrane. It furthermore enables the membrane piercing and sealing steps each to be carried out without requiring anything other than a support beneath the array. The apparatus can be used on arrays in which the tube rims are closely packed.

Another advantage of the anvil plate is that it can space the rims of the tubes apart sufficiently to prevent their welding together during the sealing process.

The anvil plate may be placed manually over the array of tubes. However, for a fully automated process, the apparatus may further comprise an anvil plate placement station, in which the anvil plate is releasably coupled to a mechanism that is moveable between a parked position in which the lower surface of the anvil plate is above the plane and the placement position. The anvil plate may be releasably coupled to the anvil plate placement station mechanism by an array of stripper pins received in the array of through holes.

Typically, the rack support supports the array of tubes within a storage rack horizontally within the apparatus, the upper rims of the tubes being in a horizontal plane. The tubes cannot be supported at too great an angle from horizontal because their contents would then be liable to spilling over the upper rims.

Whereas it is envisaged that the punch station and/or the sealing station and/or, where included, the anvil plate placement station may be moved relative to a fixed storage rack, typically the anvil plate placement station, the punch station and the sealing station will each be at respective fixed locations, with the apparatus further comprising a rack support transport assembly for transporting a storage rack containing an array of tubes within the rack support in the apparatus, to the anvil plate placement station, on to the punch station and then on to the sealing station. Where the rack is supported horizontally, the punch station and the sealing station will each be at respective fixed horizontal locations, and the rack support transport assembly would transport the storage rack horizontally.

The array of tubes typiGally comprises a regular array of x columns by y rows of tubes. This is standard in the industry. For example, a 12x8 array contains 96 tubes. The tubes in a single column may be aligned on a common column axis or, alternatively, the tubes in a single column may be aligned on a parallel adjacent pair of column sub-axes, the tubes on one of the sub-axes being staggered with the tubes on the other sub-axis. The latter arrangement is useful to more closely pack an array of circular-rimmed tubes into a given space. One example is a 6x8 array, in which each column comprises 8 rows of staggered tubes, in two sub-axes containing 4 tubes each.

With an x by y array of tubes, the punch tool may comprise an array of y punch pins, corresponding to a column of the array of tubes. By having arrays of punch pins corresponding to a single column of the array of tubes, the punch tool is able to punch a corresponding plurality of portions of sealing membrane individually and simultaneously from the remainder of the sealing membrane to overlie the associated tube rims of a whole column in a single action. This arrangement only requires relative motion between the punch tool and the rack support along an axis perpendicular to the columns in the array to punch respective portions of the sealing membrane to overlie the associated tube rims of all the tubes in the array. However, the array of punch pins may comprise just a portion of the column, even just a single pin, in which case there would be a need for relative motion between the punch tool and the rack support along axes both perpendicular to and parallel with the columns in the array. The array of punch pins may comprise a 1D array, or a 2D array spanning across more than a single column of the array of tubes.

Likewise, the sealing tool may comprise an array of y heated pins, corresponding to a column of the array of tubes, with the advantage of enabling the sealing of a whole column of tubes with a single action. Again, the array of heated pins may, like the punch pins, comprise a partial columnar array, either lDor2D.

The rack support transport assembly may be further configured to index the storage rack at the punch station by the pitch of a column so as to align the punch tool with the next column in the array of through holes.

The sealing tool is preferably located an integer number of indexed steps from the punch tool so that the sealing pins are aligned with a column of tubes in the array at the same time as the punch pins are aligned with another column of tubes in the array, so that the punch and seal operations can be carried out simultaneously on different columns of tubes. In this manner, the rack support transport assembly also indexes the storage rack at the sealing station by the pitch of a column.

Whereas the apparatus could work by supplying a series of sheets of sealing membrane to consecutive arrays of tubes, it would be operationally more efficient for the web of sealing membrane to be supplied from a continuous roll and for the sealing membrane transport mechanism to be configured to move the continuous web at least the same distance as, but preferably further than, the storage rack during the indexing of the storage rack at the punching station.

This arrangement ensures a synchronised movement of the array of tubes with the sealing web, such that there is sufficient sealing membrane material bordering the area between the punch pins and the aligned holes in the anvil plate to ensure a clean punch and hence an effective seal. The arrangement also facilitates the management of waste portions of the sealing membrane material, by ensuring that, apart from the lid portions, the cut material remains integral with the web for transport away from the punch station, rather than resulting in difficult to manage separated portions of waste material.

The sealing membrane transport mechanism may further be configured to move the continuous web past the sealing tool, whereby a portion of the web of sealing membrane is disposed between the lower surfaces of the heater pins and the upper surface of the anvil plate. This arrangement enables a compact apparatus, with the heater pins being able to move through the sealing membrane where the individual portions have previously been punched.

Where the apparatus includes a rack support transport assembly configured to transport a storage rack within the rack support in the apparatus, to the punch station and on to the sealing station, the rack support transport assembly may comprise a rack nest for receiving a storage rack, the nest including an alignment pin extending perpendicular to the plane for engagement in a corresponding hole in the anvil plate to align the anvil plate to the storage rack.

The punch tool may further comprise a compression plate surrounding the array of punch pins and having a flat lower surface resiliently mounted to the remainder of the punch tool so as to be urged against the web of sealing membrane with a predefined force. This compression plate, or shoe', ensures that the sealing membrane near the punch pins is held with a sufficient tension to prevent distortion. This helps to ensure a clean cut.

The heated pins may be resiliently mounted to the remainder of the sealing tool so as to be urged against the tube rims with a predefined force. This arrangement helps to ensure a good seal at each of the tubes and allows for some vertical misalignment between the individual tubes in the array.

The lower surface of the anvil plate is preferably profiled, having tapered projections interspersed on the lands between the through holes. The projections help to align the tubes in the array to the holes through the anvil plate. The through holes may be spaced at slightly greater intervals than the tubes in the storage rack, not least because of the need for a sufficient thickness of material between the through holes. The projections help to splay' the tubes on placement of the anvil plate over the tubes.

The cutting edge of each punch pin is typically profiled and configured to cooperate with the upper edge of the associated through hole so as to cut through the sealing material in a progressive shearing action. This keeps the punching force required to pierce and cut the sealing membrane to a minimum, which is especially important where a large number of portions are being separated from the membrane simultaneously. This also helps to maintain a clean cut and hence to ensure proper sealing of the tubes.

To further assist in aligning the punch tool to the tubes in the array, the punch tool may include a datum spike for receipt in a mating hole in the anvil plate for alignment of the punch tool with the anvil plate. This ensures that the holes through the anvil plate, which are critical for a clean cut, are not damaged by out-of-alignment punch pins.

The punch tool may be mounted to the apparatus with lateral float so as to accommodate some initial misalignment of the punch tool, specifically the punch pins, with the tubes in the array.

Similarly, to further assist in aligning the sealing tool to the tubes in the array, the sealing tool may include a datum spike for receipt in a mating hole in the anvil plate for alignment of the sealing tool with the anvil plate. This ensures that the holes through the anvil plate are not damaged by out-of-alignment heated pins.

The sealing tool may also be mounted to the apparatus with lateral float so as to accommodate some initial misalignment of the sealing tool, specifically the heated pins, with the tubes in the array.

According to a second aspect of the invention, there is provided a method of sealing an array of tubes, the method comprising the steps of: supporting an array of tubes within a storage rack, upper rims of the tubes being disposed in a horizontal plane; placing an anvil plate having upper and lower surfaces and an array of through holes corresponding to the array of tubes over the tubes to a placement position in which the lower surface of the anvil plate is below the plane and the upper surface of the anvil plate remains above the plane, the tubes being received in the corresponding through holes; translating the storage rack with anvil plate relative to a punching station; at the punching station, piercing through a web of sealing membrane overlying the anvil plate so as to cut an array of portions of the sealing membrane from the remainder of the sealing membrane, the respective portions of the sealing membrane overlying the associated tube rims; translating the storage rack with anvil plate relative to a sealing station; and at the sealing station, sealing the respective portions of the sealing membrane to the associated plurality of the rims of the tubes in the array simultaneously by the application of heat and or pressure.

The punching and sealing stations may be at fixed locations, the method including the steps of translating the storage rack with anvil plate to the punch station and on to the sealing station.

The method may further include a step of supplying a continuous web of sealing membrane to the sealing station.

The anvil plate placement step may comprise: translating the storage rack relative to an anvil plate placement station; and at the anvil plate placement station, lowering the anvil plate relative to the storage rack from a parked position in which the lower surface of the anvil plate is above the plane of the upper rims of the tubes to the placement position.

The method may yet further include a step of, after sealing the array of tubes, raising the anvil plate relative to the storage rack to the parked position. The step of raising the anvil plate relative to the storage rack may include a step of pushing the tubes out of the through holes of the anvil plate, thereby stripping the tubes from the anvil plate and ensuring the tubes remain in the storage rack whilst the anvil plate is raised clear of the rack.

The method may be carried out using the apparatus of the first aspect of the invention.

Brief Description of the Drawings

The invention will be described, by way of example, with reference to the accompanying drawings, in which: Fig.1 is a perspective view of an apparatus for individually sealing an array of tubes; Fig. 2 corresponds to Fig. 1, but with the outer cover removed to show interior mechanisms; Fig. 3 is a cross-section through the apparatus; Fig. 4 is a top perspective view of an anvil plate for an 8x12 array used in the apparatus of Figures 1-3; Fig. 5 is a bottom perspective view of the anvil plate of Figure 4; Fig. 6 is a top perspective view of an anvil plate for a 6x8 array used in the apparatus of Figures 1-3; Fig. 7 is a bottom perspective view of the anvil plate of Figure 6; Fig. 8 is a schematic cross-section through an anvil plate placement station; Fig. 9a is a schematic cross-section through punch and sealing stations, with a first column of an array of tubes aligned under the punch tool; Fig. 9b corresponds to Fig. 9a, but with the punch tool actuated to pierce a sealing membrane; Fig. 9c corresponds to Fig. 9b, but with the array indexed on a further three columns, showing the punch tool actuated to pierce a sealing membrane at the fourth column whilst the sealing tool is actuated to seal the cut portions of membrane in the first column; Fig. 9d corresponds to Fig. 9c, but with the array indexed on a further eleven columns, showing the sealing tool actuated to seal the cut portions of membrane in the last, twelfth column; Fig. 10 corresponds to Fig. 8, but showing an anvil plate stripper engaged to remove the anvil plate from the now sealed array of tubes; Fig. 11 is a perspective view from below (for clarity) of a punch tool for an 8x12 array used in the apparatus of Figures 1-3; Fig. 12 is a cross-section view through punch pins and alignment dowels of the punch tool of Fig. 11; Fig. 13 is a compound cross-section view through the punch pins and mounting screws of the punch tool of Fig. 11; Fig. 14 is a perspective view from below (for clarity) of a sealing tool for an 8x12 array used in the apparatus of Figures 1-3; Fig. 15 is a cross-section view through heater pins and alignment dowels of the sealing tool of Fig. 14; Fig. 16 is a perspective view from below (for clarity) of a punch tool for a 6x8 array used in the apparatus of Figures 1-3; Fig. 17 is a cross-section view through punch pins and alignment dowels of the punch tool of Fig. 16; Fig. 18 is a compound cross-section view through the punch pins and mounting screws of the punch tool of Fig. 16; Fig. 19 is a perspective view from below (for clarity) of a sealing tool for a 6x8 array used in the apparatus of Figures 1-3; Fig. 20 is a cross-section view through heater pins and alignment dowels of the sealing tool of Fig. 19; and Fig. 21 is a plan view of a section of sealing web membrane material having been punched.

Detailed Description

As shown in Figure 1, an apparatus 10 for automated sealing and separation of an array of tubes comprises, generally, an outer cover 12 surrounding an interior. A control panel 14 is positioned on a front side of the apparatus for a user to control operation of the apparatus. A hinged hatch 16 on the front side provides access to the interior of the apparatus. A removable bin 18 is provided at the opposite, rear side of the apparatus.

Figures 2 and 3 show the interior of the apparatus 10. In Figure 3, the hatch 16 is hinged open, with a rack support 30 projecting out of the interior for loading and unloading of a storage rack 40 containing an array of tubes 42 in an x by y array. The storage rack 40 is mounted to the rack support 30 via a rack nest 44, with respective datum features provided to ensure proper alignment of the rack with the support 30. The rack 40 may also be retained in the rack nest 44 with a clamp (not shown). The rack nest 44 has a pair of vertically projecting alignment pins 46 having chamfered ends 48 for a purpose to be described below.

For the most part, the invention will be described in the context of an 8x1 2 array of 96 tubes 42 -the 96-way' embodiment, although an alternative embodiment, corresponding to a staggered array of 48 tubes -the 48-way' embodiment will also be described.

The rack support 30 comprises a carriage 31 that is moveable into and out of the apparatus 10 by means of a stepper motor-driven lead screw 32 parallel to the rows of the tubes 42 in the rack 40, perpendicular to the columns thereof The rack support carriage 31, and therefore the array of tubes 42 within a storage rack 40 is thus translated horizontally in the apparatus with upper rims 43 of the tubes 42 in the array being disposed in a horizontal plane. Movement of the rack support carriage 31 out of the apparatus automatically opens the hinged hatch 16, against the closing action of a spring 17. When the rack support carriage 31 is moved back into the interior of the apparatus, the spring 17 urges the hatch 16 to close behind it.

The apparatus 10 is for placing an anvil plate 200 on to the array of tubes 42 within the storage rack 40. The anvil plate 200, as shown in Figures 4 and 5 in particular, has upper and lower surfaces 202, 204 and an array of through holes 206 corresponding to the array of tubes 42. The lower surface 204 is profiled, having tapered projections 211 interspersed on the lands 212 between the through holes 206. The through holes 206 of a single column are aligned on a common column axis 207. The anvil plate 200 also includes a series of pairs of registration holes 208a and 208b extending through the anvil plate 200 at either end of a column in the array of through holes 206, typically on the column axis 207. At one end, the anvil plate 200 further includes a pair of holes 210 to receive the vertically projecting alignment pins 46 of the rack nest 44, the chamfered ends 48 assisting with the insertion to accommodate slight misalignment.

Figures 6 and 7 illustrate an alternative anvil plate 200', for use with the 48-way embodiment. The anvil plate 200' essentially corresponds in all respects apart from the configuration of the through holes to the anvil plate 200, so like parts are referenced by like numerals, suffixed with a prime (). In this alternative embodiment, rather than the through holes of a single column being aligned on a common column axis, the through holes 206' of a single column are aligned on a parallel adjacent pair of column sub-axes 207'a, 207'b, the through holes 206' on one of the sub-axes 207'a being staggered with the through holes 206' on the other sub-axis 207'b, each column therefore comprising 8 rows of staggered through holes 206', in two sub-axes 207'a, 207'b containing 4 tubes each.

An anvil plate placement station 50 comprises an array of stripper pins 52 corresponding to the array of tubes 42 for engagement in the corresponding array of through holes 206 in the anvil plate 200 so as to releasably couple the anvil plate 200 in the anvil plate placement station 50. The anvil plate 200 is moveable in conjunction with the stripper pins 52 between a parked position, in which the lower surface 204 of the anvil plate is above the plane of the upper rims 43 of the tubes 42 (as seen in Figure 8), and a placement position, in which the lower surface 204 of the anvil plate is below the plane of the upper rims 43 of the tubes 42 and the upper surface 202 of the anvil plate remains above the plane (as seen in Figures 9a-d). The anvil plate placement station 50 includes a pair of downwardly projecting chamfered datum spikes or alignment dowels 54 for engagement with a pair of the registration holes in the anvil plate 200 to assist in proper alignment of stripper pins 52 to the holes 206 through the anvil plate 200. The chamfered profile of the dowels 54 aids in their insertion into the registration holes, allowing for slight misalignment.

A punch station 60 comprises a punch tool 62 having a tool body 64 and an array of vertically moveable punch pins 66 each having a cutting edge 67 on a lower end thereof. Each punch pin 66 has a dished lower surface, defining the cutting edge 67. The cutting edge 67 preferably includes spikes 67a and ramps 67b so that the cutting edge 67 cuts through the sealing material with a progressive shearing action, beginning at the spikes 67a, and progressing along the ramps 67b. Other blade profiles Gould of course be envisaged.

As best seen in Figures 11 to 13, the punch tool 62 has a plurality of punch pins 66 in a linear array. The illustrated punch tool 62 for the 96-way embodiment has 8 punch pins 66, corresponding to the 8 tubes 42 in a single column of a 12x8 array of tubes. Of course, other numbers of punch pins 66 may be used instead, either to correspond to a single column of a differently configured array of tubes, or to correspond to just a portion of a column, or to correspond to multiple columns or parts thereof.

For an array of tubes 42 having circular rims 43, each punch pin 66 and through hole 206 comprises a corresponding circular profile. Of course, other rim profiles are envisaged, with corresponding punch pin and through hole profiles.

The punch tool 60 includes a compression plate or shoe' 80 surrounding the cutting edges 67 on the punch pins 66 and having a flat lower surface 82. The compression plate 80 is mounted to the punch tool body 62 via springs 84 so as to be urged away from the tool body 62 with a predefined force.

An alternative punch tool 62' is shown in Figures 16 to 18, for use with the 48-way embodiment and the corresponding anvil plate 200'. The punch tool 62' essentially corresponds in all respects apart from the configuration of the punch pins to the punch tool 62, so like parts are referenced by like numerals, suffixed with a prime ().

A sealing station 70 comprises a sealing tool 72 having a body 74 and an array of vertically moveable heated pins 76. The heated pins 76 are resiliently mounted to the sealing tool body 74 via springs 78, as shown in Figures 14 and 15.

An alternative sealing tool 72' is shown in Figures 19 and 20, for use with the 48-way embodiment and the corresponding anvil plate 200'. The sealing tool 72' essentially corresponds in all respects apart from the configuration of the heated pins to the sealing tool 72, so like parts are referenced by like numerals, suffixed with a prime ().

A sealing membrane transport mechanism supplies a web of sealing membrane to the punch station 60 such that at least a portion of the web 90 is disposed horizontally between the upper surface 202 of the anvil plate 200 and the cutting edges 67 of the punch pins 66. The web is typically supplied in continuous form from a roll 92, with suitable tension-adjustment mechanisms such as a dancing arm 94 and a friction disc 96, the web 90 being pulled through the apparatus by a drive mechanism 98, such as a pinch roller. A guillotine 100 downstream of the web drive mechanism 98 is actuated to chop the waste web material into pieces for receipt in the removable bin 18.

The anvil plate placement station 50, the punch station 60 and the sealing station 70 are each mounted to a cradle assembly 300. The cradle assembly 300 is mounted on vertical rails 302 for movement between a raised position and a lowered position.

In operation, an operator specifies the type of rack to be sealed, for example specifying the number of tubes 42 in the array, their configuration as an array, and their size. One or more of these specifications may be detected automatically by the provision of appropriate sensors.

At a first step, with the cradle assembly 300 in the raised position (as shown in Figures 2 and 3), the rack support carriage 31 is moved out of the apparatus to a loading position. The operator loads a storage rack 40 full of tubes 42 into a rack nest 44 on the support carriage 31. The loaded carriage is then translated horizontally, by operation of the lead screw 32, into the interior of the apparatus and to a position at the anvil plate placement station 50 such that the anvil plate 200 is overlying the rack support 30, with the through holes 206 at least in approximate registration with the array of tubes 42. See Figure 8.

The cradle assembly 300 is then moved to the lowered position, moving the anvil plate 200 from the parked position to the placement position, during which the chamfered ends 48 of the vertically projecting alignment pins 46 of the rack nest 44 engage with the pair of holes 210 in the anvil plate 200 thereby aligning the anvil plate 200 more accurately to the array of tubes 42 in the storage rack 40 in the rack nest. The array of through holes 206 in the anvil plate 200 is typically on a greater pitch than the tubes 42 in the array on the storage rack 40, to allow for sufficient material between the through holes. Accordingly, placement of the anvil plate 200 on to the array of tubes 42, particularly due to the action of the tapered projections 211 on the lower surface 204, also splays the tops of the tubes apart somewhat. This may not be necessary in embodiments in which the tubes 42 are more widely spread in the rack 40, such as the 48-way embodiment. Once placed over the array of tubes 42, the stripper pins 52 are actuated to release the anvil plate 200 from the anvil plate placement station 50.

Next, the rack support 30 with the anvil plate 200 secured over the array of tubes is translated horizontally, by operation of the lead screw 32, further into the interior of the apparatus to a position at the punch station 60 such that first column of the array of tubes 42 is in at least approximate registration with the cutting edges 66 of the punch tool 62. The punch station 60 is actuated to be lowered from a raised position towards the rack support 30.

During the lowering movement, datum spikes 65 projecting downwardly from opposite ends of the punch tool 62 are received in the registration holes 208a, 208b in the anvil plate 200 for more accurate alignment of the punch tool with the anvil plate.

The compression plate 80 comes into contact with the sealing web 90 over the upper surface 202 of the anvil plate 200 and hence over the tube rims 43.

Continued downward motion of the punch tool 62 compresses the compression plate springs 84 against the tool body 64. The flat lower surface 82 of the compression plate 80 is therefore urged against the web of sealing membrane with the predefined force of the springs 84. This tensions the membrane near the cutting edges 67 so that it is held with a sufficient tension to prevent distortion.

The punch pins 66 are actuated to bring the cutting edges 67 into contact with the tensioned portion of web membrane 90, piercing, in a shearing action in conjunction with the edges of the through holes 206, circular portions 99 of the sealing membrane to overlie each tube rim 43 in the column. Those circular portions 99 will be sealed to the rims at the sealing station to become the tube lids. In the illustrated embodiments, a whole single column of the array is punched simultaneously.

Once a column of tube lids has been punched (separated from the remainder of the sealing membrane), the punch tool 62 is raised back to its initial raised position.

The rack support 30 is then indexed the pitch of a column to a position in which the next column in the array of tubes lies beneath the punch tool 62.

During the indexing movements of the rack support 30 at the punch station 60, the sealing membrane transport mechanism is actuated in conjunction with the rack support transport mechanism to ensure that an unpunched section of the web of sealing membrane 90 is brought into position beneath the punch pins 62 ready for the next punching operation. Typically, in order for the lemaining sealing membrane to have sufficient strength to tolerate the next punching operation, the web of sealing membrane 90 is in fact indexed further than the rack support, for example being indexed 1.5 x the pitch of the columns in the array whilst the rack support is indexed by a single column pitch. By indexing the web of sealing membrane 90 greater than a single column pitch, management of the waste web material is also improved. Without the additional indexing movement, diamond-shaped waste portions corresponding to the lands 212 on the anvil plate 200 would either be separated from the web, requiring waste management at the punch station 60, or would be left attached by only a very thin portion of material that could become detached from the remainder of the web, again requiring waste management. With the additional indexing movement, the punched section of web 90 looks like that shown in Figure 21, having a ladder-like appearance, with rungs' 91 spanning the web between the punched sections from which the lid portions 99 have been cut.

The sealing station 70 is located three column pitches away from the punch station 60. Accordingly, as shown in Figure 9c, once the first three columns of lid portions 99 have been punched, the next index of the rack support 30 brings the first column of tubes 42 into at least approximate registration with the sealing tool 72, and in particular with the heated pins 76.

The sealing tool 72 is lowered to bring the heated pins 76 into the through holes 206 and into contact with the circular portions 99 of sealing membrane overlying each tube rim 43 in the column. During the lowering movement, datum spikes projecting downwardly from opposite ends of the punch tool 72 are received in the registration holes 208a, 208b in the anvil plate 200 for alignment of the sealing tool with the anvil plate. The springs 78 accommodate slight vertical misalignment of the tube rims 43 and ensure a predetermined pressure is applied by the heated pins 76 during the sealing process.

Each pin 76 is individually heated. Whereas each pin 76 could have a temperature sensor to operate a feedback loop temperature control, a more economical alternative is to have a single temperature sensor associated with just one of the heated pins 76 and to use an algorithm to determine the control of both that and the other pins on the basis of the sensed temperature. A predetermined amount of heat is applied to each circular portion 99 to ensure that it is fully sealed to the associated tube rim 43. The pressure, heat and duration of contact can all be controlled to ensure a proper seal. To account for edge effects, more power could be supplied to the more exposed outer pins to ensure an even application of heat through each pin 76. In the illustrated embodiments, a whole single column of the array is sealed simultaneously.

Once a column of tube lids has been sealed, the sealing tool 72 is raised back to its initial raised position.

The rack support 30 is then indexed the pitch of a column to a position in which the next column in the array of tubes lies beneath the sealing tool 72 and the process is repeated until all columns have had the lid portions 99 sealed to their associated tube rims 43. Because of the location of the sealing tool 72 three column pitches away from the punch station 60, the final three columns of lid portions 99 are sealed at the sealing station 70 whilst the punch station 60 is no longer in registration with a column of the array.

The punching and sealing operations result in an array of individual sealed tubes, at which point the rack support 30 is returned to the anvil placement station 50 for removal of the anvil plate 200. In a reversal of the anvil plate placement procedure, the rack support carriage 31 is translated horizontally, by operation of the lead screw 32, back to the anvil placement station 50. There, the placement station 50 is lowered, bringing the stripper pins 52 into engagement with the thiough holes 206 in the anvil plate 200. See Figure 10.

The stripper pins 52 are actuated to pass into the through holes 206 to grip the anvil plate 200 and to push the sealed tubes out of the through holes 206 as the anvil plate 200 is lifted from the array of tubes. The push from the stripper pins 52 is needed because of the likelihood of the tubes having swollen within the through holes 206 during the heating of the sealing operation.

The cradle assembly 300 is then raised, lifting the anvil plate 200 clear of the array of tubes 42 to enable the rack support carriage 31 to then be ejected from the interior of the apparatus through the hatch for unloading of the finished rack by the operator.

The punch tool 62 is preferably mounted to the apparatus 10 with lateral (e.g. horizontal) float so as to accommodate some initial misalignment of the punch tool, specifically the punch pins 66 thereof, with the rims 43 of the tubes 42 in the array. This is typically achieved by mounting the tool body 64 to the rest of the punch station 60 via mounting screws 69 having shafts 69a received in larger diameter holes 63 through the tool body 64 (see Figure 13).

Similarly, the sealing tool 72 is preferably mounted to the apparatus 10 with lateral (e.g. horizontal) float so as to accommodate some initial misalignment of the sealing tool, specifically the heated pins 76 thereof, with the rims 43 of the tubes 42 in the array. This is typically achieved by mounting the tool body 74 to the rest of the sealing station 70 via mounting screws (not shown) having shafts received in larger diameter holes 73 through the tool body 74 (see Figure 15).

Instead of the anvil plate placement station 50, the punch station 60 and the sealing station 70 being at fixed horizontal locations in the apparatus, and the rack support carriage 30 translating the array of tubes 42 therebetween, the rack support 30 may be fixed in the interior of the apparatus with the anvil plate placement, sealing and punch stations 50, 60, 70 being translated horizontally into positions overlying the tubes for the respective anvil plate placement (and removal), punching and sealing operations.

Likewise, rather than the cradle assembly 300 being lowered towards the rack support 30 to position the anvil plate placement, sealing and punch stations 50, 60, 70 to perform their respective operations, the rack support 30 may instead be raised towards fixed anvil plate placement station 50, punch tool 62 and sealing tool 72. It is the relative motion of the stripper pins 52 or the punch tool 62 or the sealing tool 72 and the support 30, and hence the rims 43 of the tubes 42 in the array that is important.

Whereas the web 90 is described as being supplied on a continuous roll 92, it may instead be supplied in single sheets, each transported individually to the punch station 60 by an adapted web transport mechanism.

In the foregoing description, the processing of fully populated racks of tubes has been described. It will be appreciated that that is not necessary and that instead only partially populated racks -i.e. racks having gaps where tubes could have been received -could be processed using the same apparatus and techniques.

Also, whereas the description has concentrated on sealing new, unused tubes, it would be possible to re-seal used tubes with the apparatus and methods described, simply cutting a new lid portion to overlie the pierced lid of a previously sealed tube and sealing the new lid portion over the old lid.

Claims

CLAIMS1. Apparatus for sealing an array of tubes and for separating individual tubes from the sealed array, the apparatus comprising: a rack support for supporting an array of tubes within a storage rack within the apparatus, wherein upper rims of the tubes are disposed in a plane; an anvil plate having upper and lower surfaces and an array of through holes corresponding to the array of tubes, the anvil plate being placed on the array of tubes in a placement position in which the lower surface of the anvil plate is below the plane and the upper surface of the anvil plate remains above the plane; a punch station comprising a punch tool having an array of punch pins each having a cutting edge, wherein the punch tool is moveable relative to the rack support to a position in which the array of punch pins is brought into registration with a corresponding array of the holes through the anvil plate, and wherein the cutting edges are moveable perpendicular to the plane relative to the rack support between a position above the plane and a position below the upper surface of the anvil plate; a sealing station comprising a sealing tool having an array of heated pins each having a lower surface, wherein the sealing tool is moveable relative to the rack support to a position in which the array of heated pins is brought into registration with a corresponding array of the holes through the anvil plate, and wherein the lower surfaces of the heated pins are moveable perpendicular to the plane relative to the rack support between a position above the plane and a position in the through holes substantially aligned with the plane; and a sealing membrane transport mechanism for supplying a web of sealing membrane to the punch station, whereby at least a portion of the web of sealing membrane is disposed between the cutting edges of the punch pins and the upper surface of the anvil plate; wherein the relative movement of the cutting edges and the rack support punches respective portions of the sealing membrane to overlie the associated tube rims; and wherein the relative movement of the lower surfaces of the heated pins and the rack support seals the respective punched portions of the sealing membrane overlying the associated tube rims to those tube rims.
2. The apparatus of claim 1, further comprising an anvil plate placement station, in which the anvil plate is releasably coupled to a mechanism that is moveable between a parked position in which the lower surface of the anvil plate is above the plane and the placement position.
3. The apparatus of claim 2, wherein the anvil plate is releasably coupled to the anvil plate placement station mechanism by an array of stripper pins received in the array of through holes.
4. The apparatus of claim 1, 2 or 3, wherein the punch station and the sealing station are each at respective fixed locations, the apparatus further comprising a rack support transport assembly configured to transport a storage rack within the rack support in the apparatus, to the punch station and on to the sealing station.
5. The apparatus of claim 4, when dependent on claim 3, wherein the rack support transport assembly is further configured to transport the storage rack containing an array of tubes to the anvil plate placement station.
6. The apparatus of any preceding claim, wherein the array of tubes comprises a regular array of x columns by y rows of tubes.
7. The apparatus of claim 6, wherein the tubes in a single column are aligned on a common column axis.
8. The apparatus of claim 6, wherein the tubes in a single column are aligned on a parallel adjacent pair of column sub-axes, the tubes on one of the sub-axes being staggered with the tubes on the other sub-axis.
9. The apparatus of any of claims 6 to 8, wherein the punch tool comprises an array of y punch pins, corresponding to a column of the array of tubes.
10. The apparatus of any of claims 6 to 9, wherein the sealing tool comprises an array of y heated pins, corresponding to a column of the array of tubes.
11. The apparatus of any of claims 6 to 10, wherein the rack support transport assembly is further configured to index the storage rack at the punch station by the pitch of a column so as to align the punch tool with the next column in the array of through holes.
12. The apparatus of claim 11, wherein the sealing tool is located an integer number of indexed steps from the punch tool.
13. The apparatus of claim 11 or claim 12, wherein the web of sealing membrane is continuous and the sealing membrane transport mechanism is configured to move the continuous web at least the same distance as, but preferably further than, the storage rack during the indexing of the storage rack at the punching station.
14. The apparatus of claim 13, wherein the sealing membrane transport mechanism is further configured to move the continuous web past the sealing tool, whereby a portion of the web of sealing membrane is disposed between the lower surfaces of the heater pins and the upper surface of the anvil plate.
15. The apparatus of any preceding claim, when including the features of claim 4, wherein the rack support transport assembly comprises a rack nest for receiving a storage rack, the nest including an alignment pin extending perpendicular to the plane for engagement in a corresponding hole in the anvil plate to align the anvil plate to the storage rack.
16. The apparatus of any preceding claim, wherein the punch tool further comprises a compression plate surrounding the array of punch pins and having a flat lower surface resiliently mounted to the remainder of the punch tool so as to be urged against the web of sealing membrane with a predefined force.
17. The apparatus of any preceding claim, wherein the heated pins are resiliently mounted to the remainder of the sealing tool so as to be urged against the tube rims with a predefined force.
18. The apparatus of any preceding claim, wherein the lower surface of the anvil plate is profiled, having tapered projections interspersed on the lands between the through holes.
19. The apparatus of any preceding claim, wherein the cutting edge of each punch pin is profiled and configured to cooperate with the upper edge of the associated through hole so as to cut through the sealing material in a piogressive shearing action.
20. The apparatus of any preceding claim, wherein the punch tool includes a datum spike for receipt in a mating hole in the anvil plate for alignment of the punch tool with the anvil plate.
21. The apparatus of any preceding claim, wherein the punch tool is mounted to the apparatus with lateral float.
22. The apparatus of any preceding claim, wherein the sealing tool includes a datum spike for receipt in a mating hole in the anvil plate for alignment of the sealing tool with the anvil plate.
23. The apparatus of any preceding claim, wherein the sealing tool is mounted to the apparatus with lateral float.
24. The apparatus of any preceding claim, wherein the tubes have substantially circular upper rims.
25. A method of sealing an array of tubes, the method comprising the steps of: supporting an array of tubes within a storage rack horizontally, upper rims of the tubes being disposed in a plane; placing an anvil plate having upper and lower surfaces and an array of through holes corresponding to the array of tubes over the tubes to a placement position in which the lower surface of the anvil plate is below the plane and the upper surface of the anvil plate remains above the plane, the tubes being received in the corresponding through holes; translating the storage rack with anvil plate relative to a punching station; at the punching station, piercing through a web of sealing membrane overlying the anvil plate so as to cut an array of portions of the sealing membrane from the remainder of the sealing membrane, the respective portions of the sealing membrane overlying the associated tube rims: translating the storage rack with anvil plate relative to a sealing station; and at the sealing station, sealing the respective portions of the sealing membrane to the associated plurality of the rims of the tubes in the array simultaneously by the application of heat and or pressure.
26. The method of claim 25, wherein the punching and sealing stations are at fixed locations, the method including the steps of translating the storage rack with anvil plate to the punch station and on to the sealing station.
27. The method of claim 25 or claim 26, further including a step of supplying a continuous web of sealing membrane to the sealing station.
28. The method of any of claims 25 to 27, wherein the anvil plate placement step comprises: translating the storage rack relative to an anvil plate placement station; and at the anvil plate placement station, lowering the anvil plate relative to the storage rack from a parked position in which the lower surface of the anvil plate is above the plane of the upper rims of the tubes to the placement position.
29. The method of claim 28, further including a step of, after sealing the array of tubes, raising the anvil plate relative to the storage rack to the parked position.
30. The method of claim 29, in which the step of raising the anvil plate relative to the storage rack includes a step of pushing the tubes out of the through holes of the anvil plate.
31. The method of any of claims 25 to 30, using the apparatus of any of claims ito 24.
32. Apparatus for sealing an array of tubes and for separating individual tubes from the sealed array substantially as hereinbefore described and with reference to the accompanying drawings.