WO2009013505A1

WO2009013505A1 - Packaging system

Info

Publication number: WO2009013505A1
Application number: PCT/GB2008/002544
Authority: WO
Inventors: Simon Kew; Alexander James Marshall; Christopher Creasey; Michael Roger Cane; Jeremy Peter Clements
Original assignee: Smart Holograms Limited
Priority date: 2007-07-24
Filing date: 2008-07-24
Publication date: 2009-01-29
Also published as: GB0714420D0; WO2009013505A8

Abstract

A storage unit (10) for water-sensitive sensors comprising: a support plate (11); a plurality of wells (12), each well attached to said support plate, and each well so sized as to be able to house, in use, a water-sensitive sensor; a piercable, water- impervious sheet (17), attachable to said support plate, to seal each well; and desiccant (19, 20), located in each well. Preferred embodiments of the invention have fins (14) to grip a desiccant tablet (19), desiccant coatings (20) within the wells and markings (21, 22) to indicate how to open the pack.

Description

PACKAGING SYSTEM

Field of the Invention

The invention relates to packaging systems for the storage and transport of water-sensitive sensors, especially sensors employing holographic film, and sensors for the detection of low levels of water.

Background and Prior Art known to the Applicant

Water-sensitive sensors have been in use in a number of industries for many years. As an example, water detectors are used to detect the presence of dispersed water in aviation fuels to ensure that the levels are below the recommended limit of 30ppm. If higher levels of water are present in such fuels it may lead to operational difficulties with aircraft engines. Such sensors are not only sensitive to water dispersed within fuels, but react gradually to water vapour in the air, and contamination from environmental water sources during storage and transport. For many years, the sensors have been stored and packaged in systems illustrated in cross-section in figure 1. Individual sensors 1 are stored within a deep-drawn aluminium tube 2, which is closed with a threaded aluminium lid 3. Located at one end of the tube is a small sachet of desiccant 4 such as silica gel. For transport and storage, the tube 2 is sealed with the lid 3 by means of the interacting threaded portions 5. A resilient pad 6 is located within the lid 3 to stop the sensors 1 from rattling around when the tube is full. In use, a single sensor 1 is removed from the tube 2 by unscrewing the lid 3, and the sensor 1 is placed on the end of a syringe, which is used to draw aviation fuel through the body of the sensor 1 in order to effect the test.

Aviation fuel poses hazards to operators carrying out the tests and to mitigate these risks operators will wear heavy kerosene-resistant gloves when performing the tests. The tests may also have to be carried out on airfields and in all weathers, including rain.

It is particularly difficult for operators to be able to remove the cap 3 whilst wearing these heavy gloves in order to remove a sensor 1 from the tube 2. Also, during this operation, there is a possibility that droplets of water might enter the tube 2 so contaminating any sensors 1 remaining therein. After a sensor 1 has been removed, the lid 3 must, of course, be screwed back onto the tube 2 to protect the integrity of the remaining sensors 1.

Furthermore, each time the tube is opened, damp air and/or water droplets may enter the tube before it is resealed, thus leading to increased degradation rates of the sensors 1 despite the effect of the desiccant 4.

It is an object of the present invention to attempt a solution to these and other problems.

Summary of the Invention

Accordingly, the invention provides a storage unit for water-sensitive sensors comprising: a support plate; a plurality of wells, each well attached to said support plate, and each well so sized as to be able to house, in use, a water-sensitive sensor; a piercable, water- impervious sheet, attachable to said support plate, to seal each well; and desiccant, located in each well.

Preferably, said support plate comprises a raised portion surrounding each well. In any aspect of the invention, it is preferable that said desiccant comprises a tablet of water-absorbing material and each well further comprises inwardly-projecting fins, preferably deformable, so arranged as to grip said tablet.

Also in any aspect of the invention, it is preferable that said desiccant comprises a coating on the inside of said wells. More preferably, said coating covers all, or substantially all, of the inside of said wells.

When said desiccant comprises a coating on the inside of said wells, it is particularly preferred that said wells are of injection-moulded construction, and said desiccant is co- moulded with said wells.

Also, in any aspect of the invention, it is preferable that said wells are so sized as to be able to house, in use, only a single such sensor. In that way, the protective effect of the pack is not compromised each time a sensor is removed from the pack.

Also in any aspect of the invention, it is preferable that said sheet is marked to indicate the position of the inner wall of each well.

Also included within the scope of the invention is a storage unit substantially as described herein, with reference to and as illustrated by, any appropriate combination of Figures 2 to 13.

Brief Description of the Drawings

The invention and the prior art will be described with reference to the accompanying drawings in which:

Figure 1 is a cross-sectional view of a storage unit of the prior art;

Figures 2-3 are perspective views of a storage unit of the present invention; Figures 4-5 are top and bottom plan views respectively of a storage unit of the present invention;

Figures 6-7 are elevation reviews of a storage unit according to the present invention;

Figures 8-11 are vertical sections of wells of a storage unit of the present invention;

Figure 12 is a horizontal cross-section of a well and a desiccant tablet according to the present invention; and

Figure 13 is a top plan view of a storage unit according to the present invention.

Description of Preferred Embodiments

Figures 2 and 3 illustrate in perspective view the top and underside respectively of a storage unit according to the present invention generally indicated by 10. The storage unit comprises a support plate 11 that supports ten wells 12 each sized to house, in use, a water sensitive sensor. Other embodiments envisaged might have more, or fewer, such wells. It is envisaged that between four, and twenty such wells might be included in a single pack. Fewer than four wells has been found to result in a pack size that is either difficult to hold in a heavily-gloved hand or is wasteful of materials. Similarly, more than twenty well results in both a large pack size, and increases the likelihood of inadvertent damage to the packs during the consequent extended useful life of the pack. This embodiment is designed to hold sensors of approximately cylindrical form having a diameter of approximately 14mm and a height of approximately 8mm. Each well 12 has the form of a slightly tapered cylinder having a 4.0° of taper and a diameter at the base of 16.5mm.

The storage unit 10 is of injection-moulded plastics construction formed using polypropylene, for example polypropylene sold under the trade name MOPLEN, for example MOPLEN 548N (Basell AF SCA). Polyproplylene is particularly suitable due to its ease of mouldablity, its resistance to kerosene, and its low moisture vapour transmission rate. The overall width 13 of the storage unit is approximately 55mm allowing it to be held comfortably yet securely in a gloved hand. It is envisaged that the pack could be narrower than this, for example by having just a single row of wells or a staggered series of wells, but is preferably less than a total width of 100mm, again to allow it to be held comfortably and securely. In other envisaged embodiments, wells can be provided on a roll or in concertina form, advantageously in a dispenser that may for example, be attached to refuelling apparatus such as a tanker. The walls of the storage unit 10 are approximately 1.5mm thick. This has at least three basic advantages: firstly this thickness of polypropylene adds to the overall moisture impermeability of the pack once sealed as described below. Secondly, this thickness leads to a rigid construction of each of the wells thus positively preventing them being deformed when the pack is subjected to mechanical forces; without this rigidity, a sensor 1 would be able to be pushed through the covering sheet (not illustrated, but described below as e.g. a piercable water-impervious sheet) sealing the pack, by the kind of mechanical forces it would most likely encounter during the product lifetime. At very least, the wells are preferably rigid enough to prevent a user pushing a sensor through the covering sheet by exertion of manual pressure. Thirdly, the rigidity of the support plate allows a user to pierce the covering sheet above a well (e.g. with the end of a syringe) whilst holding the complete pack, perhaps at only one end.

Each well 12 is approximately 17.8mm deep, allowing it to accommodate both a water sensor, and a tablet of desiccant described below. Within each well 12 is located a number of inwardly-projecting fins 14 that serve to grip a tablet of desiccant located at the base of each well 12. The fins may be rigid, cutting into an outside surface of a tablet to grip it, or may be deformable, and preferably resiliently deformable, to grip a tablet by frictional forces alone.

As illustrated in figure 3, the underside of the support plate 11 is provided with a series of raised ribs 15 that serve to stiffen the support plate 11.

Running around the periphery of each of the wells 12 and formed as part of the support plate 11, is a raised portion 16 that serves as a bonding surface for a pierceable, water- impervious sheet that may be attached thereon using a suitable adhesive system. This will be described in more detail below.

Figures 4 and 5 show respectively top and bottom plan views of the embodiment of figures 2-3. It can be seen in figure 4 that each well 12 is equipped with three inwardly- projecting fins 14 to grip a tablet of desiccant.

Figures 6 and 7 show side and end elevational views of the storage unit of figures 2-5.

Figure 8 is a cross-sectional view through the line A-A of figure 6. The cross-section illustrates the location and height of the inwardly-projecting fins 14 used to hold a tablet of desiccant (not illustrated). It can be seen that the fins 14 only extend part way up the height of the well 12 thus allowing, in use, a water-sensitive sensor to sit on top of the fins 14 and thus be separated from the tablet of desiccant.

Figure 9 again shows a cross-section through a well 12 of a storage unit. The figure illustrates the raised portion 16 extending above the top surface of the support plate 11. Also illustrated in figure 9 is a pierceable water-impervious sheet 17 attached to the support plate 11 and on top of the raised portions 16, by means of glue 18. The sheet 17 is made of aluminium foil of 20micron thickness coated with a heat seal lacquer. In manufacture a desiccant tablet 19 is pressed into the well 12 and onto the inwardly- extending ribs 14 that may either flex to allow the tablet 19 to be pushed towards the base of the well, or cut into the outside surface of the tablet 19, in either case thereby securing the tablet 19 in the well 12. A water-sensitive sensor is then placed within the well and the sheet 17 heat sealed or otherwise affixed onto the support plate 11. A particular advantage of having the raised portions 16 on the support plate 11 is that any irregularities in the thickness or bowing of the support plate 11 do not interfere with the proper sealing of the well 12 by the sheet 17. By appropriate choice of the height of the raised portion 16 (in this embodiment 0.4mm) to be greater than any expected deviations in height of the support plate, a good seal between the sheet 17 and the well is ensured. Figure 10 is a cross-sectional view of an alternative embodiment of a well 12 of a support unit wherein a desiccant 20 comprises a coating on the base of the well.

Figure 11 shows a yet further embodiment of such a well where a coating of desiccant 20 covers all or substantially the entire inside of the well 12. This configuration is particularly advantageous as any moisture that diffuses through the wall of the well 12 meets the layer of desiccant 20 before it comes into contact with a water-sensitive sensor contained therein. Further advantages are also apparent with this configuration: as no desiccant tablet is required, the depth of the wells can be reduced, saving materials and reducing the overall bulk and weigh of the pack. This is particularly important as the devices are often shipped by air to their place of use, in airfields. Using the example of an 8mm deep sensor, the overall well depth could readily be reduced to only about 10mm.

hi either of the embodiments of figure 10 or figure 11, the desiccant can be co-moulded with the wells 12 as part of an injection moulded construction.

Figure 12 is a horizontal cross-section along the line B-B of figure 9 and illustrates the location of a tablet of desiccant 19 held in position within a well 12 by three radially spaced apart inwardly-projecting fins 14. By holding the desiccant tablet within the well in this way, a water-sensitive sensor may be removed from the storage unit after removing the protective sheet 17, by inverting the opened well; the sensor will fall from the well leaving the desiccant 19 held firmly in place.

Figure 13 illustrates a top plan view of a storage unit according to the present invention with a layer of pierceable water-impervious sheet 17 sealing each of the wells 12 of the storage unit. Water-sensitive sensors of the type stored in such a unit are often connected to a syringe or other suction device by means of a connector such as a Luer connector located in the central region of the sensor. To open the package, the sheet, such as foil, may be pierced with the end of the syringe to introduce the syringe end into the Luer connector. To an operator in a hurry, and perhaps working in poor light conditions, the obvious way of piercing the sheet would be to stab the end of the syringe into the centre of the foil covering a well. However, there is a chance that piercing the foil in this way will result in a portion of the foil blocking the fluid connection between the syringe and the sensor. In the embodiment of figure 13, therefore, the sheet 17 is marked, in this case with a dot 21 to indicate the location of the inner wall of each well. For clarity, only two such dots are illustrated in figure 13. The provision of such markings ensures that an operator does not puncture the foil in the central location. A further such marking, e.g. a curved arrow 22 is also provided to indicate that, when an operator has pierced the foil at the position of the dot 21, they should drag the syringe end around the inside edge of the well as indicated by the arrow 22 in order to open the well.

The invention also provides, therefore, a method of dispensing a water-sensitive sensor, from a pack having a piercable covering, comprising the steps of: piercing said covering, preferably with the tip of an aspiration apparatus, adjacent a side wall of a sensor enclosure; tearing said covering by movement of the tip around the side wall, so exposing the sensor; and forming a connection between said aspiration apparatus and said sensor.

Claims

1. A storage unit for water-sensitive sensors comprising: a support plate; a plurality of wells, each well attached to said support plate, and each well so sized as to be able to house, in use, a water-sensitive sensor; a piercable, water-impervious sheet, attachable to said support plate, to seal each well; and desiccant, located in each well.

2. A storage unit according to claim 1 wherein said support plate comprises a raised portion surrounding each well.

3. A storage unit according to either preceding claim wherein said desiccant comprises a tablet of water-absorbing material and each well further comprises inwardly-projecting fins so arranged as to grip said tablet.

4. A storage unit according to any of claims 1 and 2 wherein said desiccant comprises a coating on the inside of said wells.

5. A storage unit according to claim 4, wherein said coating covers all, or substantially all, of the inside of said wells.

6. A storage unit according to either of claim 4 or 5 wherein said wells are of injection- moulded construction, and said desiccant is co-moulded with said wells.

7. A storage unit according to any preceding claim wherein said wells are so sized as to be able to house, hi use, only a single such sensor.

8. A storage unit substantially as described herein, with reference to and as illustrated by, any appropriate combination of Figures 2 to 13.