TECHNICAL FIELD The present invention relates to a thermal element for the accumulation and emis- sion of thermal energy for thermally influencing the environment, according to the preamble of the appended claim 1.

The present invention also relates to a thermal wrapping for the accumulation and emission of thermal energy for thermally influencing the human body, according to the preamble of the appended claim.

The present invention also relates to a method and a machine for the manufacture of a thermal element, according to the preamble of the appended claims 5 and 7, respectively.

The present invention also relates to a cooling device for cooling the thermal ele- ments or wrappings, according to the preamble of the appended claim.

BACKGROUND ART It is previously known to arrange thermal elements constructed from plastic films enclosing reservoir spaces containing water and a chemical cooling agent.

However, the known kind of thermal element becomes rather stiff when frozen down, i. e. when using the thermal element for cooling purposes, due to the stiffness of the plastic films at low temperatures. With known solutions, one has thereby had to resort to cooling agents with a freezing-point reducing effect, in order for the fluid not to freeze and thus further reduce the pliability of the element.

DISCLOSURE OF INVENTION The object of the present invention is to provide a thermal element or wrapping that is highly flexible, without, to that end, resorting to costly, freezing-point reducing cooling agents.

Said object is achieved by a thermal element or a wrapping according to the char- acterising parts of claims 1 or 11. Said object is also achieved by a method and a device for the manufacture of a thermal element according to claims 5 or 7, respec- tively, or by a cooling device according to claim 17.

BRIEF DESCRIPTION OF DRAWINGS The invention will be explained further below, by way of some embodiment exam- ples, with reference to the enclosed drawings, in which Fig. 1 illustrates, in a partially cut-through perspective view, an example of the thermal element ; Fig. 2 illustrates, in a perspective view, a machine for manufacturing the thermal element ; Figs. 3 and 4 show a front view and a side view, respectively, of a first section of the machine ; Fig. 5 illustrates, in a partially cut top view, the thermal element comprised in the thermal wrapping according to the invention ; Fig. 6 shows a partially cut section through the thermal element according to fig.

5 ; Fig. 7 shows a top view of the thermal wrapping according to the invention, in the form of a waistcoat, in an outspread state ; Fig. 8 shows the waistcoat ready for use ; and Fig. 9 shows a refrigerating box for cooling the thermal wrapping or element.

PREFERRED EMBODIMENT Fig. 1 thus illustrates an example of the thermal element 1, showing that the basic structure of the element consists of two plastic films of a highly flexible and tem- perature-indifferent material. An example of such a film is based on polythene, where each film is constructed from a laminate consisting of several film layers. The two plastic films 2,3 are connected to each other along elongated connecting seams, comprising a first set of connecting seams 4-8, extending, in the embodi- ment shown, in one and the same general direction, and a second set of connecting seams 9-12, running across the first set and thus extending in a different general direction, for example transversely in relation to the first set. The connecting seams

of the first set thus cross the connecting seams of the second set at a multitude of crossings. The connecting seams are entirely sealed and thus continuous, for delimiting together a multitude of reservoir spaces 14, created through the two plas- tic films thus being separable from each other between the connecting seams, as the plastic films are not completely stretched but the films can define, between each adjacent seam, biconcave reservoir walls 15,16. Each reservoir space 14 is thus delimited by a portion of the connecting seams ; more specifically, if one of the reservoir spaces is studied, a portion 17 of the connecting seam 5 of the first set of connecting seams, a portion 18 of the connecting seam 6 of the first set, a portion 19 of the connecting seam 11 and a portion 20 of the connecting seam 10 of the second set. The reservoir spaces 14 thus obtain a generally pillow-shaped form and are, seen from above, substantially square, more specifically rectangular, in the illustrated example. The connecting seams preferably consist of welding seams and are for example 3-4 mm wide. The connecting seams 4,8, 9,12 define exterior edges of the thermal element.

The reservoir spaces 14 are filled with a fluid acting as thermal heat carrier, capable of accumulating and slowly emitting thermal energy through the plastic films 2, 3 ; for example, the fluid substantially consists of water. The water may either be cooled down, e. g. be frozen in a refrigerating box, see below, or a deep-freezer, or be heated in water in a cooking pot. Water is cost saving and environment-friendly. The reservoir spaces 14 and the film walls 15,16 will certainly be very rigid when freez- ing the water, but the connecting seams 4-8, 9-12 will remain highly pliable and flexible and may serve as hinges for folding the element about each connecting seam, about folding axes in their longitudinal direction, whilst simultaneously bend- ing it into a curved shape for adaptation to e. g. a double-curved area, for example a knee, for cooling down an injury on the human body. This is possible by selecting the highly flexible and even at low temperatures somewhat elastic plastic film mate- rial, which has a very high strength and will withstand a lot of folding and bending.

The basic element described above may, in a preferred embodiment, be supple- mented by two exterior films 21,22, joined with the two interior films 2,3 along the exterior edges 4, 8,9, 12 of the element. The two exterior films 21,22 will create a surrounding cover, like a bag, and are provided with at least a couple of aeration

holes to allow enclosed air to escape. Thus, the exterior films do not follow the exact shape of the reservoir spaces, but will provide a smoother exterior surface and will furthermore protect the inner films against damage.

The reservoir space 14 thus consists of an enclosed cavity 23, delimited by the wall sections 15,16 of the two films.

With reference to Figs. 2,3 and 4, the machine and the method will be described in the following. The machine for manufacture of the thermal elements is constructed of a frame 24, supporting a multitude of rollers cradled in the frame, of which a first section of the machine, for producing the basic element without the exterior plastic films 21,22, will initially be described. The inner plastic films 2,3 are each unwound in steps from a storage roll 25,26 and passed over a common conducting roller 27 at the top of the first section of the machine, which is substantially supported by two vertical frame parts 28. The two plastic films unwound in steps then run downwards, generally vertically, on each side of a ramp 29 extending transversely between the films, to which ramp a number of feeding lines are leading, corresponding to the number of rows of reservoir spaces. The feeding lines 30,31, 32,33 come from a feeding device with a valve unit 100 functioning to dispense water amounts. The valve unit 100 is in turn controlled by a control unit, to be further described below.

From the ramp 29, elongated, substantially parallel filling tubes 35, 35'36, 37" extend, at their lower ends provided with mouths 38-41 at a predetermined level in the machine. Below the ramp 29 a first welding device 42 is arranged for providing the first set of connecting seams. The welding device 42 is for example comprised of a heating unit having two welding jaws, one on each side of the films to be welded and exhibiting welding means for e. g. during stepwise feeding of the plastic films 2, 3, i. e. the forward feeding steps, being brought into contact with the films and creat- ing the first set of weld seams along a length corresponding to the length of the cooling element. Hereby, elongated ducts are created, into which the filling tubes 34-37 extend. Forward feeding of the plastic film is performed by means of a feeding device using hydraulic or pneumatic cylinders 43,44, turning feeder rolliers 45,46 on each side of the plastic films, said rollers being in contact with the films during each

forward feeding step, and being separated therefrom during the retraction move- ment.

At the lower end of the machine, a second welding device 47 is arranged for trans- verse weiding of the two plastic films. The second welding device 47 also exhibits, see Fig. 4, two welding jaws 48, 49, one on each side of the films, with welding means for creating the second set of weld seams 9-12. In the illustrated example, having weld jaws providing one transverse weld at a time, the whole forward feeding of the plastic films occurs in steps corresponding to the distance between said weld seams.

For each transverse connecting seam 9-12 created, the elongated ducts form a pocket having a bottom, enabling the filling with water through each filling tube 34- 37, in an amount corresponding to the volume of each reservoir space. A sensing device controlling the valve unit 100 performs the dosing of the water volume for each reservoir space very accurately. In the illustrated example, the sensing device is a level gauge for sensing the filling level and controlling the valve unit 100.

Through the transverse welding, the reservoir spaces are delimited, and after a pre- determined number of transverse welds, determining the length of the element, the element is finished and cut along a connecting seam defining the external edges 9, 12. The cutting is performed by means of a cutter device 50 that is advanced towards the films between each forward feeding step and performs the cutting, whereupon the finished product will fall down onto a feeder device 51 in the form of a conveyor, running generally horizontally through the second section of the machine.

The second section of the machine is shown in Fig. 2 and is arranged along the horizontal feeder device, and is mainly supported by a basic structure of horizontal frame girders 53 extending throughout the entire machine. The feeder device 51 thus consists of a conveyor belt 54 that is endless and is linked around guide rollers 55 at the ends of the machine. At the starting end 56 of the machine, there is a coil roll 57 for one of the exterior films, in the illustrated example consisting of the lower film. This film is fed forward and placed onto the conveyor belt 54 for supporting the

finished basic element, which is guided down at an angle relative to the conveyor belt and the film by an incline guide plate 58, see Figs. 3 and 4. From a further storage roll 59, located downstream of the first section of the machine, producing the basic element, the second exterior film 22 for creating the upper exterior film is guided via guide rollers down towards the top side of the basic element, which is fed forward on the conveyor belt. 54. A welding device 61 is arranged for providing a transversal connection between the exterior films, before and after the basic ele- ment, respectively. The transversal connections can be performed directly at the connection with the transversal exterior edges 4,8 of the basic element, or just out- side thereof. At a further welding device 62, longitudinal connecting seams are pro- duced between the exterior films in order finally to seal the exterior films into an exterior cover. This creates the bag-like cover. The aeration holes may be pre- manufactured in the fiim or may be performed at some location before the films are connected to the basic element. Adjacent to the last welding device 62, a cutting off of the bag-like exterior cover is performed with a spacing thus exceeding the length of the basic element. The two welding devices 61,62 are controlled with a cycle frequency that is thus lower than the other forward feeding steps of the device, which are determined by the unit having the shortest step movement, i. e. the trans- verse welding, which has to be performed in steps equal to the spacing of the trans- verse welds, i. e. the length of the reservoir spaces in the forward feeding direction.

The finished products will leave the conveyor belt 54 at the finishing end 63 of the machine, where the products can be allowed to slide down along an inclined guide plate 64.

In the foregoing, the machine, and, in connection therewith, to a certain extent also the method according to the invention for manufacturing the thermal elements, has been described. The method can be summarised by the main steps of : a) feeding two plastic films 1,2 forward in a downwards direction, on both sides of a multitude of filling ducts 34-37, b) connecting the two plastic films longitudinally, outside and between each filling duct, respectively, for fluid-tight seating between the individual ducts, c) connecting the plastic films transversely, below the mouths of the filling ducts, by fluid-tight connecting seams, created one at a time,

d) filing of water, via the filling ducts, with a carefully determined volume of water through each filling duct ; after creating each transverse connecting seam. e) cutting off the connected plastic films along certain ones of the trans- verse connecting seams, after creating a preselected number of water-filled reser- voir spaces.

In a second step, the method may be complemented by a method for enclosing the basic thermal elements in a bag-like exterior cover, locating the basic thermal elements somewhere between two exterior plastic films 21,22, enclosing the basic thermal elements by connecting the two exterior plastic films adjacent to the exterior edges of the basic element, whereby transversal and longitudinal connecting seams are created.

The connecting seams can, in principle, be created by heating the plastic films by means of electrically heated welding jaws, whereby the plastic film material is melted together. Alternatively, so-called high frequency welding may be used. In principle, the connection can also be achieved by other means, through adding strings of adhesive and gluing the plastic films together to create the connecting seams.

In principle, the step feeding can be performed in various ways, but it is always required to create one transverse weld at a time below the water filling location in order to allow the filling of water into each transversal row of reservoir spaces. In principle, a continuous feeding velocity is also conceivable, however it must be selected so as to allow sufficient time for completion of the transverse welding and the water filling.

The thermal element can be used in a number of different ways through being com- bined with some form of suitable cover or through being located in a suitable way for either cooling or heating of some area, body, or a space containing air or fluid. Thus, the basic element may also be used entirely separately, by being immersed into a fluid for changing the temperature thereof. The thermal element can be placed inside a cover where one side is thermally insulating and the other side consists of e. g. a thin material that will allow passage of the thermal energy ; either cold or heat.

Examples of such products are cooling bandages for cooling injuries to the human body, for example sports injuries, whereby the element is placed in a pocket-like cover, for example complemented by Velcro fasteners. A similar, pocket-like cover could enclose a beverage bottle, for either cooling or heating thereof. Other applica- tion areas would be salvaging vests, provided with a heat-insulating and reflecting extemal cover and on the inside being provided with pockets, into which the thermal elements are placed, after being stored in a freezer, for cooling down a human body during fire-fighting.

The reservoir spaces 14 thus consist of closed chambers, delimited by the wall sections 15,16 of the two films and containing a fluid, preferably water, storing the thermal energy and emitting it successively to the environment, in this case the human body, for cooling or heating thereof.

The thermal element described above is for example intended for use in the thermal wrapping according to the invention which, according to the example in Figs. 7 and 8 is illustrated in the form of a waistcoat 121, shown in Fig 7 in an outspread, flat state. The waistcoat is made of a highly flexible material, for example a textile mate- rial forming a cover, and is provided with an exterior that is preferably moisture and heat repellent. In an application as a protective waistcoat for fire fighting, the flexible material is flameproof. The waistcoat can be regarded as comprising three portions, named after their location on the human body, i. e. a chest portion 122, a back portion 123 and an intermediate shoulder portion 124. The chest portion and the back portion may in principle be identical. The unit could have a generally rectan- gular principal shape, but preferably with a larger width across the chest portion and the back portion, allowing them to meet during use with as little clearance as possi- ble, see Fig. 8. The chest portion and the back portion are provided with connection members 125 in the form of e. g. Velcro straps along their longitudinal edges, allow- ing the chest portion and the back portion to be connected to each other in a vari- able manner, depending on the body size of the bearer. In this manner, the waist- coat can in principle be produced in one size only, or in only a few sizes. The shoul- der portion 124 is provided with a neck opening 126, large enough to allow the waistcoat to be pulled over the head of the bearer. In certain embodiments, the shoulder portion can however be opened at least in one direction, altematively in

both directions, along a joint 127, which is held together by e. g. Velcro straps and can be opened to facilitate putting on the waistcoat. Such an application might be the use as a cooling waistcoat for medical purposes, for cooling the human body in case of accidents.

The thermal properties of the thermal wrapping, in the illustrated example of the waistcoat, are obtained through arranging a number of thermal elements of the ini- tially described kind on the inside of the flexible wrapping or cover. In the illustrated example, four thermal elements are provided in pockets 128, 129,130 and 131 on the inside of the flexible cover. More precisely, in the illustrated example two pock- ets are provided on the inside of the chest portion 122 and two pockets are provided on the inside of the back portion 123. It is conceivable to arrange similar pockets on the inside of the shoulder portion 124. The pockets are designed to cover a maxi- mum area of the chest portion and the back portion, respectively, and are made of a material more penetrable for thermal energy than the exterior coating, i. e. thermally only to a iimited extent, or not at all insulating material. This will allow the thermal energy to pass at an appropriate rate through the inside of the pocket towards the body, in order to maintain said body at a temperature deviating from the ambient temperature on the outside of the wrapping. The dominant application relates to cooting, i. e. the thermal elements consist of cooling elements intended either for protecting the body against temperature increase due to a high ambient tempera- ture, e. g. a fire, or for lowering the body temperature below the ambient tempera- ture, e. g. during cardiac trouble or for storage of recently deceased persons. In order to avoid excess cooling whilst simultaneously achieving as extended a cooling effect as possible, a certain insulation of the inside of the pockets may in some cases be appropriate. The technical effect should however mainly be directed towards the body of the bearer.

The pockets exhibit, in connection with their upper sections, i. e. the sections turned towards the shoulder portion 24, an opening 132 in the form of an opening edge, from which an attachment section 33 of the thermal element protrudes, se also Figs. 5 and 6. At one end of the thermal element, one edge portion is wider than the other edge portions and defines this attachment section, by the two film layers 2,3 being connected to each other over an area or by a seam running around the attachment

section. The attachment section is provided with fastening members intended for interaction with fastening members on the inside of the flexible cover surface of the waistcoat at the opening edge 132. In an advantageous embodiment, said fastening members are Velcro straps, one part being fastened to the attachment section 133 and the other part extending across the chest and the back portions, respectively, of the waistcoat at the opening edge 132. Advantageously, the thermal element is sized so that the attachment section 133 at least partly, or fully, protrudes from its pocket 128-131, and that the Velcro strap 135 on the cover is likewise located above the opening edge 132. With advantage, the pocket may be sized so that the thermal element will not stand on the bottom of the pocket, but remains hanging inside the pocket, thus achieving maximum flexibility. In practice, however, the bottom of the pocket will, together with the attachment section 133, carry the load from the thermal element. The thermal element has a width that is slightly smaller than the width of the pocket, i. e. substantially corresponds to that width, thus achieving maximum cooling surface.

According to the arrangement described above, the thermal elements can be easily exchanged for e.g. cooling in a refrigerating box or a deep-freezer, or removed for cleaning of the waistcoat. Alternatively, the waistcoat or the wrapping, together with the thermal elements, can be cooled as a unit, to be quickly exchanged for a waist- coat, the cooling effect of which has ceased.

Fig. 9 illustrates an example of a refrigerating box for storage and cooling of thermal wrappings according to the invention. The refrigerating box 136 is preferably con- structed as a thermally insulated box having a lid 137 and an enclosed space 138 for storing the thermal wrappings or elements 1, which can be stacked in a number depending on the volume of the refrigerating box. Inside the refrigerating box a refrigerating device 139 is provided, in the illustrated example consisting of an orifice manifold exhibiting a multitude of orifices or outlet openings 141 directed towards the elements 1, and being provided with a connection to the outside of the box through a connection nipple 140. Via the nipple, a coolant, such as carbon-dioxide snow from a carbon-dioxide cartridge 141, as partly hinted in the figure, can be sup- plied to the orifice manifold 139, which cartridge can be connected via the nipple 140 for injection of coolant to the interior of the box, i. e. to the thermal elements or

wrappings. Through this, the temperature in the space 138 can be maintained at a very low level, for example -80°C, so that the cooling medium, substantially water, in the thermal elements, is frozen into ice and will create a cold magazine having a very high cooling effect.

The invention is not limited to the embodiment example described above and illus- trated in the drawings, but can be varied within the scope of the appended patent claims. For example, the exterior cover could be eliminated, and the number of res- ervoir spaces could be varied to a large extent. The shape could also be varied. It is conceivable that the welding seams would not be entirely parallel or would not cross each other at right angles. The essential feature is that the thermal elements are provided with seams that are so flexible, pliable and also longitudinally somewhat flexible, that the thermal elements can be bent, not just into a single-curved shape but into a double-curved shape, so that each connecting seam not only serves as a bending joint but can also be arched, for example for following a double-curved surface.

In case a quick recharging of the cooling effect is needed, the waistcoat with its cooling elements may be placed on any surface and sprayed with carbon-dioxide snow from a fire extinguisher. The wrapping does not have to be designed like a waistcoat, but may have arms with or without cooling elements. The wrapping can also be designed like a blanket having a multitude of pockets for the cooling ele- ments or the heating elements. Independently of the design, the wrapping cover can be provided with a heat-insulating layer outside of the thermal elements.