Cartridge Sealing Apparatus
20210284368 · 2021-09-16
Inventors
Cpc classification
B65B7/28
PERFORMING OPERATIONS; TRANSPORTING
B29C66/53461
PERFORMING OPERATIONS; TRANSPORTING
International classification
B65B7/28
PERFORMING OPERATIONS; TRANSPORTING
B29C65/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
There is provided a cartridge sealing apparatus (1) comprising a sealing head (10) having a sealing surface (12), the sealing head being adapted in use to hold a sealing member (70) against a surface of a cartridge (100) by application of pressure to the sealing member at the sealing surface across a portion of the sealing member, a bonding layer being present between the sealing member and the cartridge thereby causing the sealing member (70) to seal the cartridge when held against the surface of the cartridge; and a cutting edge (20) arranged around the sealing head (10). The cutting edge is configured to move when the sealing member is held against the surface of the cartridge by the sealing head, from an unextended position, in which the cutting edge is located adjacent the sealing head, to an extended position, in which the cutting edge is adapted to cut the sealing member.
Claims
1. A cartridge sealing apparatus comprising: a sealing head having a sealing surface, the sealing head being adapted in use to hold a sealing member against a surface of a cartridge by application of pressure to the sealing member at the sealing surface across a portion of the sealing member, a bonding layer being present between the sealing member and the cartridge thereby causing the sealing member to seal the cartridge when held against the surface of the cartridge; and a cutting edge arranged around the sealing head, wherein the cutting edge is configured to move when the sealing member is held against the surface of the cartridge by the sealing head, from an unextended position, in which the cutting edge is located adjacent the sealing head, to an extended position, in which the cutting edge is adapted to cut the sealing member.
2. The cartridge sealing apparatus according to claim 1, wherein the cartridge is a chemical cartridge suitable for holding one or more chemical reagents.
3. The cartridge sealing apparatus according to claim 1, wherein the sealing head and cutting edge are adapted to move in a single continuous movement relative to each other to seal the sealing member to the cartridge and cut the sealing member.
4. The cartridge sealing apparatus according to claim 1, further comprising a heater configured to provide heat to the sealing head in use, wherein the heater is thermally coupled to the sealing head.
5. (canceled)
6. The cartridge sealing apparatus according to claim 4, wherein the heater is a heating pad having a shape corresponding to the shape of the sealing surface.
7. The cartridge sealing apparatus according to claim 4, wherein the heater is configured to heat the sealing surface to about 200 degrees centigrade (° C.).
8. The cartridge sealing apparatus according to claim 4, wherein the sealing head further comprises a heat sink.
9. The cartridge sealing apparatus according to claim 4, further comprising a temperature sensor coupled to the sealing head.
10. The cartridge sealing apparatus according to claim 1, wherein the cutting edge is a knife blade with a chisel grind having a first side parallel to a side of the sealing head and a second side at an angle to the first side, and wherein the second side is on a proximal side of the cutting edge to the sealing head.
11. (canceled)
12. The cartridge sealing apparatus according to claim 1, wherein the cutting edge is arranged around the perimeter of the sealing surface so as to cut the sealing member at the perimeter of the sealing surface.
13. The cartridge sealing apparatus according to claim 1, wherein the sealing head and cutting edge form a unitary body, the sealing head being moveable relative to the cutting edge to move the cutting edge between the unextended position and the extended position, and wherein the sealing head is pushed by a biasing member to a first position in which the cutting edge is in the unextended position, and wherein the biasing member is a resiliently deformable member comprising an array of compression springs.
14. (canceled)
15. (canceled)
16. (canceled)
17. (canceled)
18. The cartridge sealing apparatus according to claim 14, wherein the sealing head is moveable from the first position to a second position by the application of a first force having a component perpendicular to the sealing surface when the sealing head is holding the sealing member against the cartridge thereby sealing the cartridge, the cutting edge being closer to the sealing surface in the second position than in the first position, and wherein the sealing head is adapted to apply uniform pressure to the sealing member on movement of the sealing head from the first position to the second position.
19. (canceled)
20. The cartridge sealing apparatus according to claim 18, wherein the sealing head is moveable from the second position to a third position by application of a second force having a component perpendicular to the sealing surface when the sealing head is holding the sealing member against the cartridge, movement of the sealing head from the second to the third position causing the cutting edge to move from the unextended position to the extended position, wherein the second force is greater than the first force.
21. The cartridge sealing apparatus according to claim 18, wherein the sealing head is made of Invar.
22. (canceled)
23. The cartridge sealing apparatus according to claim 1, wherein the sealing head is adapted to apply a pressure of about 0.90 Newtons per square millimetre (N/mm.sup.2) at the sealing surface to seal the cartridge.
24. The cartridge sealing apparatus according to claim 1, wherein the sealing head is adapted to apply a pressure of about 1.89 N/mm.sup.2 at the sealing surface when the cutting edge moves from the unextended position to the extended position.
25. A method of sealing a cartridge, the method comprising: applying pressure to a sealing member at a sealing surface of a sealing head to hold a portion of the sealing member against a surface of the cartridge, a bonding layer being present between the sealing member and the cartridge thereby causing the sealing member to seal the cartridge when held against the surface of the cartridge; and cutting the sealing member with a cutting edge arranged around the sealing head while the sealing member is held against the surface of the cartridge by moving from an unextended position, in which the cutting edge is located adjacent the sealing head, to an extended position, in which the cutting edge cuts the sealing member.
26. The method according to claim 25, wherein the sealing member is sealed to the cartridge before the sealing member is cut.
27. The method according claim 25, wherein the sealing head and cutting edge move in a single continuous movement relative to each other to seal the sealing member to the cartridge and cut the sealing member.
28. The method according to claim 25, wherein a first pressure is applied to the sealing member when sealing the sealing member to the cartridge, and the method further comprising applying a second pressure to the sealing member at the sealing surface when cutting the sealing member, and wherein the second pressure is greater than the first pressure.
29. (canceled)
Description
BRIEF DESCRIPTION OF FIGURES
[0039] An example of a cartridge sealing apparatus is described in detail below, with reference to the accompanying figures, in which:
[0040]
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[0050]
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DETAILED DESCRIPTION
[0055] We now describe one example of a cartridge sealing apparatus and a method of sealing a cartridge. The cartridge sealing apparatus is part of a larger production line used to fill and seal a chemical cartridge.
[0056] In this example the cartridge is a chemical cartridge, and as such, the sealing apparatus is a chemical cartridge sealing apparatus. As shown in
[0057] Before being sealed, each chemical cartridge 100 is placed underneath a chemical reagent dispensing array nozzle. Reagents are then dispensed into each of the wells 120, 130 as required for the purpose for which the chemical cartridge is intended to be used.
[0058] The chemical cartridge 100 is then removed from underneath the array nozzle and is placed underneath the chemical cartridge sealing apparatus 1, which is generally illustrated, inverted, in
[0059] As is shown in
[0060] The base plate 30 provides support for the retaining plate 22 and the sealing head 10. Support is provided by the base plate for the sealing head in that the sealing head 10 is biased by compression springs 60 (shown in
[0061] In order to provide suitable support, in this example, the base plate is made of En24T steel. This is becauseEn24T steel is a high tensile alloy steel that is suitable for high stress environments and has low thermal expansion (of about 12 microns per metre Kelvin (pm/m.Math.K)).
[0062] The isolation plate 40 provides thermal and electrical insulation to the base plate 30, the retaining plate 22 and the sealing head 10. This is achieved by the isolation plate being made of polyether ether ketone (PEEK) in this example.
[0063] The sealing head 10 is shown in more detail in
[0064] The heating pad 14 is also is in contact with a sheet of ceramic paper 16 on the opposite side of the heating pad to that in contact with the pressure plate 13. The ceramic paper provides thermal insulation between the heating pad and a backing plate 18 to which the opposing side of the ceramic paper is in contact and thereby forms an interference fit with. This causes the heat to be directed towards the sealing surface and ensures good contact between the heating pad and the sealing surface due to the compression the ceramic paper applies to the heating pad. The backing plate 18 acts as a heat sink so that any heat that passes to the backing plate is spread across the plate. This helps keep the temperature of the sealing head 10 as uniform as possible when heat is applied using the heating pad.
[0065] The heating pad 14 is an electrical heating pad to which power is supplied by wires 50. To monitor the temperature of the heating pad, a sensor 19, shown in
[0066]
[0067] As shown in
[0068]
[0069] As mentioned above, this produces an interference fit between the backing plate and the ceramic paper.
[0070] When the chemical cartridge apparatus is assembled, one of the springs 60 is located in each recess. As shown in
[0071] The arrangement of the recesses 11 in the array on the backing plate 18 allows the springs 60 to apply force evenly across the backing plate so that pressure is able to be applied evenly at the sealing surface 12. In total, there is a deflection across the backing plate caused by the force applied by the springs of about 0.02 mm at room temperature and pressure when the chemical cartridge sealing apparatus is assembled. The ceramic paper 16 and the heating pad 14 are able to be compressed. Because of this, and the interference fit between the backing plate, the ceramic paper 16, heating pad 14 and the pressure plate 13 the maximum deflection of the pressure plate at room temperature when the chemical cartridge sealing apparatus is assembled is about 20 microns (μm).
[0072] The electrical connection by wires 50 to the heating pad 14 is also show in
[0073] As mentioned above,
[0074] The pressure plate 13 also has a protrusion 134 around its side. When assembled, the protrusion extends outwardly from the side of the pressure plate to a distance at which it matches the perimeter around the backing plate 18 provided by the upstanding wall 182. As explained in more detail below in relation to
[0075]
[0076] A portion of the sealing head 10 is shown in
[0077] As mentioned above, there is a gap between the upstanding wall 182 and the protrusion 134. The size of the gap varies depending on the amount of pressure that is applied to the backing plate due to compression of the ceramic paper 16 and the heating pad 14. When no pressure is applied, the heating pad has a thickness of about 0.14 mm and the ceramic paper has a thickness of about 0.80 mm, which gives a combined thickness of about 0.94 mm. When a pressure is applied to the backing plate equivalent to of about 0.34 N/mm.sup.2 (about 340 kilopascals (kPa)) at the ceramic paper, which corresponds to a pressure of about 0.90 N/mm.sup.2 (about 900 kPa) at the sealing surface 12, the combined thickness of the heating pad and the ceramic paper is reduced to about 0.54 mm. At these pressures the distance between the upstanding wall and the protrusion is about 0.40 mm.
[0078] As is explained in more detail below, the pressure of about 0.34 N/mm.sup.2 at the ceramic paper and about 0.90 N/mm.sup.2 at the sealing surface is only the initial pressure applied during the chemical cartridge sealing process. The final pressure applied during the chemical cartridge sealing is about 0.71 N/mm.sup.2 (about 710 kPa) at the ceramic paper, which corresponds to a pressure of about 1.89 N/mm.sup.2 (about 1890 kPa) at the sealing surface.
[0079]
[0080] The example shown in
Example of Chemical Cartridge Sealing Apparatus in Use
[0081] An example of the chemical cartridge sealing apparatus in use is now described.
[0082] Initially the sealing head is heated using the heating pad located between the pressure plate and the backing plate of the sealing head. The sealing head is heated to a final temperature of about 160° C. to 240° C. as measured by the sensor. This is achieved by providing about 150 Watts (W) of power to the heating pad. When the temperature of the sealing head is about 20° C. before being heated, the sealing head takes about 540 seconds to reach the final temperature.
[0083] When the sealing head reaches the final temperature, its temperature is maintained at the final temperature. This is achieved by switching the power to the heating pad off and on sequentially based on the temperature monitored by the sensor. This allows reduction in the temperature of the sealing head due to the effect of heat loss, for example though the springs, through which there is a heat flux loss of 5 Watts per square metre (W/m.sup.2), to be kept to a minimum.
[0084] Due to the material of the pressure plate and backing plate, only a small amount of expansion occurs due to the increase in temperature. The material used for these components is Invar 36 (also known as FeNi36 or 64FeNi), which is a nickel-iron alloy. The coefficient of thermal expansion of each of the pressure plate and backing plate is about 4.2 μm/m.Math.K. This is low compared to ordinary steels, which have a coefficient of thermal expansion of about two and a half to about three and a half times larger than that of the Invar used for the pressure plate and backing plate, and prevents the pressure plate and backing plate from expanding and becoming jammed or stuck against the inside of the retaining plate, which itself (along with the base plate) is made of a steel (a P20S steel with a Brinell Hardeness (BH) of about 300).
[0085] The sealing plate and the backing plate also have a thermal conductivity of about 10 Watts per metre Kelvin (W/m.Math.K) and a specific heat capacity of about 515 Joules per kilogram Kelvin (J/kg.Math.K). As a comparison, the heating pad, which is an All Polyimide heater made with copper, has a thermal conductivity of 390 W/m.Math.K and a specific heat capacity of about 390 J/kg∜K, the ceramic paper, which is a silicon paper in this example, has a thermal conductivity of about 1.5 W/m.Math.K and a specific heat capacity of about 877 J/kg.Math.K; and the isolation plate, which, as mentioned above is made of PEEK, has a thermal conductivity of about 00.25 W/m.Math.K.
[0086] Once the sealing head has reached the final temperature it is ready to be used to seal a chemical cartridge. This is achieved by positioning a chemical cartridge underneath the sealing surface of the pressure plate and placing a sealing member over the chemical cartridge covering the wells in the chemical cartridge. In this example, the foil sheet sealing member has a lacquer coated on the side that is to be sealed to the chemical cartridge.
[0087] At this stage the driver of the sealing apparatus 1, shown in
[0088] When the sealing apparatus 1 is held in this position, the springs 60 push the backing plate and pressure plate as far forward within the retaining plate 22 as possible. This causes the sealing surface 12 to extend beyond the cutting edge 20 leaving the cutting edge located around the side of the sealing plate 13. The forward movement of the sealing plate is limited due to the protrusion 134 of the sealing plate abutting an inwardly projecting shelf 222 of the retaining plate (shown in
[0089] To seal the sealing member to the chemical cartridge, the sealing surface 12 is brought into contact with the sealing member. This is achieved, as shown by
[0090] When the sealing surface comes into contact with the sealing member, as shown in
[0091] The pressure applied to the sealing member at the sealing surface rises to about 0.90 N/mm.sup.2 at which point the springs are caused to compress. This causes a constant pressure to be applied to the sealing member with each spring providing a force of about 263 Newtons (N) to the backing plate. As indicated in
[0092] Due to the compression of the springs, the cutting edge 20 moves closer to the sealing member. However, it does not come into contact with the sealing member at this stage. This movement of the cutting edge towards the sealing member is due to the protrusion 134 of the pressure plate 13 no longer abutting the shelf 222 of the retaining plate 22 as springs get compressed and the distance between backing plate 14 and the base plate 30 is reduced moving the shelf of the retaining plate away from the protrusion of the pressure plate.
[0093] By the end of the 7.6 seconds over which pressure is applied, the sealing member is sealed to the chemical cartridge. This is achieved due to the applied heat and pressure causing the lacquer coat on the sealing surface to bond with the chemical cartridge.
[0094] As shown in
[0095] Once the cutting edge 20 has cut the sealing member, the springs are fully compressed with the backing plate 18 in contact with the base plate 30. Accordingly, the cutting edge extends past the sealing surface 12.
[0096] The pressure in the upper portion of the chamber 304 is then released and the sealing apparatus 1 is raised out of contact with the chemical cartridge and sealing member by providing a higher gas pressure in the lower portion of the chamber than in the upper portion of the chamber. The chemical cartridge with the sealing member sealed thereto is then moved away for packing or further processing and a further chemical cartridge is put in its place with a new sealing member placed over it as described above.
[0097] In an example not shown in the diagrams, the retaining plate has a plurality of cutting edges and a plurality of sealing plates. Each of the cutting edges is located around one of sealing plates and the method described above is used to seal a plurality of chemical cartridges at the same time.
[0098] As a further example, the cutting edge is shaped so as to act as a guillotine. This is achieved by having a longer blade at one point around the cutting edge and a shorter blade at an opposing point around the cutting edge with a tapered blade between the two opposing points. This provides a leading edge of the cutting edge that pierces the sealing member before other parts of the cutting edge and a trailing edge that pierces the sealing member last.
[0099] Additionally, in any example the cutting edge is able to be jig ground to provide a cutting edge that is hardened for toughness.
[0100] In another example, the same cartridge, sealing apparatus and sealing method as set out above can be used for a non-chemical application. Such an application includes cartridges suitable for food, dry goods or to package items like electronics.
[0101] While in the examples described above the cartridge has a plurality of wells (such as the cartridge 100 shown in