RELATING TO, HEATING PADS FOR BULK CONTAINERS

Abstract

The invention is for a heating pad for a container to lie against at least one external surface of the container, and apply thermal energy to the container, and any material therein, when needed. The pad consists of a foamed resilient substrate with a first presenting major surface substantially equal in area to the at least one external surface of the container. A heating cable is located on the first presenting major surface to form an electrical circuit that when energised provides the thermal energy. A planar sheet material is above the first presenting major surface, and below a second presenting major surface of the substrate, the planar sheet material extends past the first and second presenting major surfaces and sealed at a periphery to form an encapsulation of the substrate and heating cable. There is an electrical connection from the heating cable internally of the encapsulation to external of the encapsulation. Such that the heating pad can be located against the at least one external surface of the container to move with that container, and when connected to a source of electricity can supply thermal energy to the container and any material contained therein.

Claims

1. A heating pad for a container to lie against at least one external surface of the container, and apply thermal energy to the container, and any material therein, when needed, comprising or including, a foamed resilient substrate with a first presenting major surface substantially equal in area to the at least one external surface of the container, a heating cable located on the first presenting major surface to form an electrical circuit that when energised provides the thermal energy, a planar sheet material above the first presenting major surface, and below a second presenting major surface of the substrate, the planar sheet material extending past the first and second presenting major surfaces and sealed at a periphery to form an encapsulation of the substrate and heating cable, wherein the planar substrate has a pathway formed on the first presenting major surface as a recess into the planar substrate to receive the heating cable, an electrical connection from the heating cable internally of the encapsulation to external of the encapsulation, such that the heating pad can be located against the at least one external surface of the container to move with that container, and when connected to a source of electricity can supply thermal energy to the container and any material contained therein.

2. The heating pad according to claim 1 wherein the resilient substrate is planar or curved when manufactured to match the contour of the container.

3. (canceled)

4. The heating pad as claimed in claim 1 wherein the pathway is a series of preformed connected radial or parallel grooves.

5. The heating pad as claimed in claim 1 wherein a thermal output of the heater cable is below a thermal capacity of the planar substrate and planar sheet material to prevent it from burning.

6. The heating pad as claimed in claim 1 wherein the planar substrate and planar sheet material have a thermal dissipation rate that is greater than the thermal output rate of the heating cable when energised.

7. The heating pad as claimed in claim 1 wherein the second presenting major surface is parallel to the first major presenting surface.

8.-9. (canceled)

10. The heating pad as claimed in claim 1 wherein the electrical connection is also physically connected to the planar substrate or planar sheet material such that it can also be used as a handle to manoeuvre at least the heating pad without pulling out from the heating pad or affecting the connection to the heating cable.

11. The heating pad as claimed in claim 1 wherein the seal at the periphery lies substantially between the first presenting major surface, and the second presenting major surface.

12.-14. (canceled)

15. The heating pad as claimed in claim 1 wherein the heating pad can flex in and out of plane of the major surfaces without breaking.

16. The heating pad as claimed in claim 1 wherein the planar substrate can deform at least in part to contour to the underside of the container to improve transfer of the thermal energy.

17. The heating pad as claimed in claim 1 wherein the container is an intermediate bulk container (IBC), or drum.

18. The heating pad as claimed in claim 1 wherein the heating pad lies between the container on top and a pallet system below, the pallet allowing ease of lifting and transport.

19. The heating pad as claimed in claim 1 wherein the heating pad may be held against one or more sides and top of the container.

20. The heating pad as claimed in claim 1 wherein a thermal control device within the encapsulation controls the energisation of the heating cable.

21. A method of manufacture of a heating pad for location at least against at least one external surface of a container to apply thermal energy to the container when connected to an electrical source, comprising or including the steps of, providing a foamed resilient substrate with an first presenting major surface substantially equal in plan area to the underside of the container, forming a pathway in the planar substrate on the first presenting major surface as a recess into the planar substrate, locating a heating cable on the first presenting major surface to form an electrical circuit that when energised provides the thermal energy, surrounding the substrate and heating cable with a planar sheet material above the first presenting major surface, and below a second presenting major surface of the substrate, the planar sheet material extending past the major surfaces, sealing the planar sheet material at a periphery to form an encapsulation of the substrate, and the heating cable, providing an electrical connection from the heating cable internally of the encapsulation to external of the encapsulation, such that the substrate, heating cable and in part the electrical connection are sealed from the environment external to the planar sheet material to provide a heating pad that when needed is connected to a source of electricity to supply heat to the container and any material contained therein.

22.-24. (canceled)

25. The method as claimed in claim 15 including the step of physically connecting the electrical power cord to at least a part of the heating pad such that it can also be used as a handle to manoeuvre at least the heating pad without pulling out from the heating pad or affecting the connection to the heating cable.

26. The method as claimed in claim 15 including where the connection is by at least one anchor to the planar substrate, directly or indirectly.

27. The method as claimed in claim 15 including the step where the seal at the periphery lies between the first presenting major surface, and the second presenting major surface.

28.-36. (canceled)

37. The method as claimed in claim 15 including the step of locating and electrically connecting a thermal control device within the encapsulation to control the energisation of the heating cable.

38. A container in combination with a heating pad against at least one external surface of the container, the heating pad comprising or including, a foamed resilient substrate with a first presenting major surface substantially equal in area to the at least one surface of the container, the foamed resilient substrate having a pathway in the planar substrate on the first presenting major surface as a recess into the planar substrate, a heating cable located on the first presenting major surface to form an electrical circuit that when energised provides the thermal energy, a planar sheet material above the first presenting major surface, and below a second presenting major surface of the substrate, the planar sheet material extending past the major surfaces and sealed at a periphery to form an encapsulation of the substrate and heating cable, an electrical connection from the heating cable internally of the encapsulation to external of the encapsulation, such that the heating pad can be located against the external surface of the container to move with that container, and when needed connected to a source of electricity can supply thermal energy to the container and any material contained therein.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Preferred forms of the present invention will now be described with reference to the accompanying drawings in which;

[0080] FIG. 1 shows an exploded view of an intermediate bulk container, heating pad of the present invention, and pallet for the heating pad and container to rest on,

[0081] FIG. 2 shows a side view of the arrangement of FIG. 1,

[0082] FIG. 3 shows a cut away view in plan of the heating pad in accordance with the present invention,

[0083] FIG. 4 shows a vertical partial cross section of the heating pad from FIG. 3 in isometric form,

[0084] FIG. 5 shows an exploded view of FIG. 4, and

[0085] FIG. 6 shows an end view of the detail from FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0086] Preferred embodiments will now be described with reference to FIGS. 1 through 6.

[0087] The general shape of one form of the heating pad 1, when located under a container 2 and above a pallet 14, is shown in FIGS. 1 and 2. It should be understood that when the term container is used, it means a rigid container within which the bulk product is contained, as well as a flexible container, such as a liner bag, plastic or otherwise, which is then contained in a frame or similar to restrain it. The heating pad 1 in this case will sit against the flexible container, between it and any restraining frame, secondary container, or similar.

[0088] In the embodiment shown the heating pad 1 is substantially the same plan area as the underside of the container 2. The container 2 could be rigid, semi-rigid or flexible, for example a bag with a supporting structure for the container. The heater is normally inside the supporting structure against the container 2(whether rigid, semi-rigid or flexible). This ensures uniform heating of the container 2 and its contents. In some embodiments it is sufficient to heat only the underside of the container 2 due to the rate of heating, and that once a thermal current is present then the lowest part of the container typically has the coolest material. Therefore, from an efficiency of heating aspect, and to not overheat the material this makes sense. However, in other embodiments the heating pad 1 may be located on other surfaces, for example the top or side, or may be on more than one side, and in some embodiments may be located on all sides, top and bottom. This works easily when the container 1 is an intermediate bulk container of parallel or planar sides. However the container 1 may also be cylindrical or other shape. In all these use scenarios the heating pad 1 may be formed to cover the area desired and conform to its shape. For example where the container 2 is cylindrical then the heating pad 1 may be shaped to conform to the curved sides, and also have a circular component to cover the top and or bottom. When the heating pad is located on a side or other surface of the container where it is not held in place by gravity, for example on the top or bottom of the container, then straps or other methods known in the art may be used to hold the heating pad to the required amount against the container.

[0089] In the embodiments where there are two or more heating pads 1, these are connected to each other to heat the container 2 at the same time, and they may have a controller within them to allow control of the supply of the thermal energy. Alternatively the heating pads 1 may each be connected to a separate, or linked external controller (not shown), to control their energisation and thermal energy application. Such control may simply be energisation without feedback, or may feedback the temperature, whether a proportional feedback from inside the heating pad, or by on off energisation control from within the heat pad.

[0090] The general features of the heating pad 1 are visible also in FIGS. 1 and 2, as is the electrical connection 11, in this case as a plug 16 which terminates a length of electrical power cord 17. The heating pad 1 has a periphery 10 and the electrical connection 11, via the electrical power cord 17 passes from external of the periphery 10 and the external environment to internally of the periphery 10. The heating pad 1 has a first external surface 20 and a second external surface 21. In the embodiment shown these are substantially planar in form, and in the orientation shown the first external surface 20 is upwardly presenting and is the face that locates against the surface of the container, and the second external surface 21 is lowermost presenting, and is the face that locates, for example against the pallet 14. As discussed surfaces 20 and 21 could for example be curved or similar to match the contours of the container 1 to be thermally controlled normally heating, but in some embodiments it may be cooling for example by using the thermoelectric or Peltier effect, so it is to be understood that thermal energy could be addition of energy to heat the material, or removal of thermal energy to cool the material.

[0091] The container 1 normally is of a standardised size, for example an intermediate bulk container 1 is normally a cubic metre. As such there is sufficient mass to form a high pressure between the underside (in this case) of the container 1 and the upward presenting major surface 4 of the heating pad 1 and the heating cable 5. Application of pressure reduces the thermal resistance across the interfaces between the heating cable 5, thermal spreading layers 18, sheet material 7A and the container 1.

[0092] The internal components of the heating pad 1 are visible in FIG. 3 which is a plan cut-away view. The external layers are formed from a thin flexible sheet material 7 which has a seal 9 (visible in FIG. 4-6) at the periphery 10. Preferably the sheet material is in the range of 0.2 mm to 3 mm thick, and ideally is in the range of 1 mm to 2 mm thick. The sheet material 7 is flexible and preferably airproof, and preferably waterproof, and preferably foodsafe. The sheet material 7 is also preferably inert and un-reactive with the agents and environments it typically comes into contact with, for example gasses and liquids. Further the sheet material preferably keeps these properties over a wide range, or the range, of temperatures the heating pad is expected to encounter. As an example the sheet material may be a woven material which is then plastic material coated, such that it is flexible strong, waterproof, airproof, foodsafe and inert.

[0093] The sheet material 7 preferably is capable of being sealed to itself, to, for example form the seal 9 at the periphery 10. Such a seal may be achieved by high frequency sonic welding, bonding, adhesives, gluing or thermally or other techniques known in the art for joining such materials. In the preferred form as shown in FIGS. 4-6 the seal lies between the upper most surface of the upper sheet material 7A, and lower most surface of the lower sheet material 7B, and preferably lies between the first presenting major surface 4 and the second presenting major surface 8.

[0094] Underneath the sheet material 7 is, in the preferred embodiment, an upper thermal spreading layer 18A. This material performs the function of dissipating the heat from the heating cable 5 across a greater area, and then passes it to the underside of the upper sheet material 7A, to at least in part help avoid hotspots. In other embodiments the heating cable may be replaced with an equivalent element, such as those known in the art, for example a printed or etched circuit, carbon fabric element and other equivalents known in the art.

[0095] Any material that performs a thermal spreading function may be used for 18A and 18B, and in the preferred embodiment this is a metallised foil, for example aluminium, or aluminium alloy foil. Any material that is malleable or that otherwise can conform to the heating cable 5, the substrate below and sheet material above to reduce the thermal resistance can be used.

[0096] Below the upper thermal spreading layer 18A is a heating cable 5. This is laid out in a desired pattern to form an electrical circuit. In the form shown, the heating cable 5 runs in long parallel runs up and down the length, or across the width of the heating pad. The exact layout pattern will vary as desired for the shape of heating pad, for example it may take a circular form when the heating pad is circular, the path will also take account of any bending that may occur, for example when applied to a curved surface, to put the least strain on the heating cable.

[0097] Below the heating cable 5, is a lower thermal spreading layer 18B, again to perform a similar function as 18A. The two layers 18A and 18B may just be laid in place, or may be sealed at their periphery's, or in addition between the cables, to hold the heating cable 5 in place, and/or to provide additional functionality such as water proofing or similar. The malleability of the layers 18A and 18B will allow them to deform about the heating cable 5 to increase thermal conductivity, and to hold the cable 5 in place.

[0098] Below the lower thermal spreading layer 18B is a planar substrate 3. The substrate is preferably within the range of 2 mm to 20 mm thick, and ideally is within the range of 5 mm to 15 mm thick. This has the function of imparting a majority of the shape retention, whether planar, curved or otherwise, to the heating pad 1. In the preferred the planar substrate is stiff but may bend or flex as needed, and may also be locally deformable. In other forms the substrate 3 may be bend out of plane, for example to form a cylinder for applying heat to a drum or other curved container. What ever form, planar, curved or otherwise, the substrate, and thus the heating pad is formed into, it is also resilient to allow bending as needed. For example the pallet that a heating pad 1 is located on may warp or bend, likewise a curved heating pad may need to be opened up to apply or remove it from a curved container such as a drum. In these situations the substrate and resulting heating pad 1 are sufficiently resilient to allow such bending without failure of permanent deformation. Such deformation may also be due in some part to handling, for example sliding over an uneven surface. It is desirable that that heating pad in this case does not fail, but is resilient to deal with such deformation. The heating pad may allow deformation between 0 mm to 100 mm over a 1 m width of heating pad, and ideally the heating pad will only suffer between 1 mm to 30 mm out of plane bending. Similar figures apply for a curved heating pad.

[0099] The substrate, and resulting heating pad 1 can also deform or dent by local compression. Ideally such compression is not permanent and is recoverably after removal of the force, for example the load of the container, is removed.

[0100] This local and global deformation resilience allows the resultant heating pad 1 to contour to the container 1 and, for example to the pallet 14 it is sandwiched between for example if the container has local deformations for example from manufacture or subsequent handling. It also gives the heating pad 1 resilience when being handled, stored and shipped, for example is the container, or pallet or similar has a gross deformation, for example it is bent or otherwise deformed over its width or length. Further, being locally deformable, will allow it to dent and thus reduce or prevent damage to the heating cable 5, where otherwise such an impact would sever or similar, the heating cable 5. In doing so the planar substrate 3 acts to protect the heating cable 5 and helps to prevent damage to it or breakage.

[0101] In the preferred form the planar substrate also has high thermal resistance. This helps it to prevent wastage of thermal energy to and through the lower presenting major surface 8, which in turn helps the efficiency of the pad 1 and drives the thermal energy into the container 1. In the preferred form the planar substrate is a foamed material, ideally closed cell, such as a high density polyurethane foam or similar. The planar substrate 3 may be cast in the particular form as needed, or may be heated and then formed, and/or may be machined as desired.

[0102] There is only a substrate below the heating cable, there is no substrate located above the heating cable. This results in a thin heating pad that reflects the thermal energy upwards and there is little blocking transmission of the thermal energy from the heating cable to the container and material therein.

[0103] Shown in FIG. 4 and in particular in 5, the planar substrate 3 has pre-formed recesses 13 as a series of connected radial or parallel grooves in its upper or first presenting major surface 4. These are to receive the lower thermal spreading layer 18B and in particular the heating cable 5. As they are connected they act as a guide for placing the heating cable during manufacture, and in use provide a permanent relief for the heating cable into the substrate, and reduce the load on the heating cable. In the preferred form the recesses 13 follow the pathway 12 of the heating cable 5. This provides further protection for the cable, and also reduces the localised pressure on the cable, planar substrate and upper sheet material 7A when in use. The result is a reduction in hot spots and also the chance of breakage of the heating cable 5 and or its rubbing through the upper sheet material 7A. The recesses may be moulded or machined into the substrate.

[0104] In the preferred form the materials for the planar substrate, thermal spreading layer and sheet material are chosen such that their thermal dissipation or thermal capacity, taking into account also the resistance of the thermal interfaces between each layer, is greater than the thermal input or output rate from the heater cable 5 when energised, this prevents the creation of hotspots and therefore reduces the chance of early degradation or failure of the heating pad or its components. Ensuring there are no, or few hotspots will prevent damage to thermally sensitive material contained in the container.

[0105] The electrical power cord 17 is also anchored to the planar substrate 3. This can be achieved by one or more physical connections 19 between the electrical power cord 17 and the substrate, and may for example involve winding the electrical power cord through a labyrinth to further increase the anchoring. The result, when all assembled is the electrical power cord 17 is securely attached to the heating pad 1 and reduces the likelihood of it be pulled out or otherwise threatening the integrity of the electrical circuit 6. The electrical power cord then also forms a handle for manoeuvring of at least the heating pad 1 itself

[0106] When manufacturing the heating pad 1, the planar substrate 3 with its recess pathway 13 for the thermal cable 5 is presented and the lower thermal spreading layer 18B is laid over the top of the planar substrate 1. The heating cable 5 is then laid on top and into or above the recesses 13. The heating cable is then connected to any thermal control device 15 (optional) and that in turn is connected to the electrical power cord 17 to thus form the electrical circuit 6. The top thermal spreading layer 18A is then laid over the top. In other forms there may be a subassembly of the heating cable 5 already sandwiched between the bottom and top thermal spreading layers 18B and 18A. The resulting assembly then has the upper and lower sheet materials 7A and 7B located about it and the periphery 10 is then sealed to form the seal 9. Any plug needed is also connected to the electrical power cord 17.

[0107] The foregoing description of the invention includes preferred forms thereof. Modifications may be made thereto without departing from the scope of the invention.