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(11) | EP 3 381 830 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | ISOTHERMAL BAG |
| (57) The invention relates to an improved isothermal bag, made up of a containing part
(P) and a cover (T), the containing part made up of walls (1, 2), joined together
by at least one seam (3) and made up of an outer fabric (11, 21), an inner fabric
(12, 22) and insulation (A) arranged between the outer fabric (11, 21) and the inner
fabric (12, 22), the seam (3) of which passes through the outer fabrics (11, 21),
the inner fabrics (12, 22) and the insulation (A).
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TECHNICAL FIELD
[0001] The present invention relates to an isothermal bag, the purpose of which is to transport products that require a controlled temperature. Specifically, it is a bag for sectors that are primarily focused on distributing temperature-sensitive products.
[0002] The main characteristic of the invention, to ensure the proper functioning thereof, is that the bags have the lowest possible heat transfer coefficient (effective thermal conductivity) between the interior and exterior of the same. In other words, it is sought that the rate of heat exchange between the interior and exterior of the same be the lowest possible during a previously established evaluation time. This way, the bag will have greater autonomy when maintaining its interior temperature within a specific range, with or without the use of hot or cold thermal accumulators, which may or may not be based on eutectic gels, which, in turn, will allow for optimal planning with regard to the distribution of products contained in the bag.
[0003] Moreover, with regard to their use in multiple work cycles, the bags must have qualities such as resistance, hygiene and durability in intensive conditions of use.
BACKGROUND
[0004] The rapid rise and perfection of hot and cold chains, increasingly controlled in greater detail, requires the development of thermally insulated containers, such as boxes and bags. Some sectors stand out in this regard, such as meal delivery services, the distribution of pharmaceutical and biotechnology products, and sectors related to the vastly extended world of e-commerce (electronic commerce), such as the distribution of food products, both refrigerated and frozen.
[0005] The present invention falls within the sector of isothermal or thermally insulated bags and has two significant advantages compared to other conventional solutions.
[0006] The first advantage consists of the lightness (under 1 Kg of weight when empty, for a capacity of 36 liters), maneuverability, bendability and ability to be stacked of the present invention, compared to rigid containers based on conventional cellular polymeric insulation, which allows costs associated with storage to be optimized, a key for sectors with a high turnover.
[0007] The second advantage consists of optimization in the distribution and sewing of the insulating materials, in order to avoid the presence of thermal bridges affecting thermal effectiveness.
[0008] All of the isothermal bags have a containing part and generally comprise a cover. In a specific type of bag, bendable and with a parallelepiped shape, the containing part is made up of walls which are joined together by seams.
[0009] The walls of the thermal bags are usually made up of an outer fabric and an inner fabric, which are structural fabrics, and insulation arranged between the outer fabric and the inner fabric.
[0010] However, the seams of the known bags constitute thermal bridges, since at the edges there is discontinuity with respect to the insulation layers that make up the bottom and the inner walls.
DESCRIPTION OF THE INVENTION
[0011] To overcome the drawbacks of the state of the art, the present invention proposes an isothermal bag, made up of a containing part and a cover, the containing part made up of walls joined together by at least one seam and formed by an outer fabric, an inner fabric and an insulation arranged between the outer fabric and the inner fabric, wherein the seam passes through the outer fabric, the inner fabric and the insulation.
[0012] Therefore, according to the invention, the seam or seams pass through the insulation layers and reduce the distance between both, eliminating the distance "d" that separates said layers, which is found in bags of the state of the art and shown in Figure 2. The inventors have found that in a 30-60 liter bag the heat flow rate is reduced by up to 30% with respect to a bag of the state of the art or, that is to say, the amount of time the thermal conditions are maintained inside the bag is extended by up to 40%. In other words, the invention consists of extending the insulation layer beyond the seams.
[0013] Preferably, the invention is applied to a bag in which a front wall, a rear wall, two lateral walls and a bottom are defined.
[0014] In some embodiments, the front and rear walls comprise additional insulation which has greater rigidity than the insulation of the lateral walls.
[0015] This way, the user can have the bag in two extreme configurations, one with greater volume which has a parallelepiped configuration, and another with less volume which has a triangular elevation cross-sectional configuration. Apart from these two configurations, others in which the elevation cross-section is trapezoidal can be defined. The closure means will be designed so that the bag can be closed at least in the two extreme configurations, for example, providing strips of Velcro at different positions of the front face, as will be seen further on.
[0016] In some embodiments, the additional insulation for the front and rear walls is XPS (extruded polystyrene).
[0017] In general, the bags are designed with front and rear walls that are larger than the lateral walls. This allows transportation to be more comfortable, either for carrying it on one's back or in one's hand. Therefore, the more extensive surfaces correspond to the front and rear wall in order for rigid insulation to be applied, which is cheaper and provides less heat conductivity. And for the lateral walls, intended to be bent so that they can take on different configurations, a material may be used that is flexible with low density, having less insulating ability, but with less impact on losses, given that it has a smaller surface. To compensate for the lower insulating ability of the lateral walls, the lateral insulation may be provided in two layers.
[0019] In some embodiments, the insulation of the front, rear and lateral walls is made up of a single piece.
[0020] This way, the insulating capacity can be further improved. In this embodiment, a pretreatment of the insulation layer may be carried out, consisting of loosening the edges, for the purpose of facilitating the definition thereof. In another embodiment, it may be envisaged that the insulation of the bottom has continuity with the lateral insulation. Preferably, on the edges in which there is no continuity, the main inventive concept shall be applied, consisting of sewing the insulation layer.
[0022] In some embodiments, the insulation is a flexible foam, preferably low-density polyethylene foam (less than 30 Kg/m3).
[0024] In some embodiments, the cover is extended at the free edges thereof by means of three flaps, the flaps and the edges being free from the mouth of the container provided with closure means.
[0026] Advantageously, the bag comprises straps joined to the upper and lower edges of the rear wall.
[0028] In some embodiments, the bag comprises inner pouches intended to contain heat or cold accumulators.
[0029] Lastly, the front and rear walls have a height comprised between 35 and 45 cm, a base comprised between 30 and 40 cm, and the lateral walls have a height comprised between 35 and 45 cm and a base comprised between 20 and 25 cm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] As a complement to the description, and for the purpose of helping to make the characteristics of the invention more readily understandable, in accordance with various practical embodiments of the bag, said description is accompanied by a set of figures constituting an integral part thereof, which by way of illustration and not limitation represent the following:
Figure 1 is a perspective view of a bag to which the present invention is applicable.
Figure 2 shows a seam according to the state of the art.
Figure 3 shows a seam of an edge of the bag, according to the invention.
Figure 4 shows a section of a bag, according to an embodiment of the present invention, wherein each wall is sewn to the adjacent wall.
Figure 5 is an embodiment wherein the insulation is continuous throughout the perimeter and only one seam is necessary, made according to the principle of the present invention.
Figure 6 is an embodiment that is provided with flexible insulation, which requires continuity, in combination with rigid insulation arranged on the larger walls of the bag, which must not be bent when storing the bag.
Figure 7 is a perspective view of a practical embodiment of the bag when it is shaped in a trapezoidal configuration.
Figure 8 is a perspective view of the bag in Figure 7 when it is shaped in a parallelepiped configuration.
Figure 9 is a perspective view of the bag in Figure 7 when it is shaped in a triangular configuration (smallest volume).
DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
[0031] Figure 1 shows an isothermal bag made up of a container part P, defining a front wall P1, a rear wall P3, two lateral walls P2, P4 and a bottom F, as can be seen in Figure 4 in a cross-sectional view.
[0033] The bag is preferably made of fabrics that can be adapted to the configuration illustrated, in other words, in a parallelepiped shape.
[0035] In a known manner, these walls are made up of an outer fabric 11, 21, an inner fabric 12, 22, and an insulation A arranged between the outer fabric 11, 21 and the inner fabric 12, 22. In other words, the inner and outer fabrics make up the structural part and the insulation A is arranged between them.
[0036] However, according to the present invention, as shown in Figures 3, 4, 5 and 6, the seam 3 passes through the outer fabrics 11, 21, the inner fabrics 12, 22, the insulation A and, eventually, a protective lining on the edges 4. In the figures, at the level of the seams, the layers are represented with a space between them, for the purpose of distinguishing them. It must be stated that it is obvious that said space does not exist, since the seam will press the layers together.
[0037] Therefore, if on the edges of bags of the state of the art there is a thermal bridge of a width "d", as indicated in Figure 2, according to the present invention, that distance is reduced to 0. The result, as has been proven by the inventors, is a 30% reduction in the total insulation coefficient of the bag for a bag with a 36-liter capacity, transporting a frozen product (with a temperature below -14°C) (obviously measured with the bag correctly closed) and in comparison with a bag model that is similar in everything except in the extension of the insulation layer beyond the seam.
[0038] According to an especially preferred variant of the invention, the cross-section of which is shown in Figure 6, all of the walls comprise the flexible insulation A, the ends of which are sewn to configure the edges, but in which the front walls P1 and rear walls P3 comprise additional insulation A2 which has a greater rigidity than the insulation A of the lateral walls P2, P4.
[0039] This way, the user can have the bag in two different configurations, one with greater volume which has a parallelepiped configuration, shown in Figure 8, and another with less volume which has a triangular elevation cross-sectional configuration, as shown in Figure 9. Halfway between the two is the configuration shown in Figure 7. The different rigidity between the materials, in other words, flexible on the sides and rigid on the front and rear walls, guides the user in the process of bending the bag.
[0040] As an additional insulating material A2 of the front wall P1 and rear wall P3, XPS may be used.
[0041] According to a preferred embodiment illustrated in Figure 5, the insulation A of the front wall P1, rear wall P3 and lateral walls P2, P4, is a single piece, meaning it is continuous except at one of the edges. In this case, the edges can be loosened, or the inner and outer fabrics can be joined by seams. Obviously, it may be envisaged that the pattern of insulation also includes the bottom F of the bag and the top cover, taking the shape of a cross, or equivalent shapes.
Materials:
[0042] Nylon is the preferred material for the outer fabric 11, 21 and the inner fabric 12, 22. For the flexible foam that constitutes the insulation, low-density closed cell polyethylene foam is preferred.
[0043] With respect to the cover T, it is extended at its free edges by means of three flaps T1, as shown in Figure 1. These flaps T1 and the free edges of the mouth of the container P are provided with closure means 5, which in an especially preferred embodiment are Velcro, which allow for a sufficiently insulating closure, which is at the same time versatile.
[0044] Moreover, as can be seen in Figures 7 to 9, the bag comprises straps 6, joined to the upper and lower edges of the rear wall P3. This way it may be carried like a backpack, especially adapted for use on bicycles. Likewise, a handle 7 joined to the central part of the upper edge is envisaged, enabling the user to carry the bag in their hand.
[0045] Envisaged on the inner surface of the walls are inner pouches intended to contain thermal accumulators, for either heat or cold, for example containing containers with gels, hydrogels, eutectic salts or PCMs (phase change materials). The inner pouches are preferably made of a mesh-type fabric.
[0046] As preferred dimensions, it is envisaged that the front wall P1 and rear wall P3 have a height comprised between 35 and 45 cm, a base comprised between 30 and 40 cm, the lateral walls P2, P4 having a height comprised between 35 and 45 cm and a base comprised between 20 and 25 cm.
[0048] Specifically, a procedure for manufacturing a bag is described, the bag made up of a containing part P and a cover T, which comprises the steps of:
- a) providing at least two walls 1, 2, each one made up of an outer fabric 11, 21, and an inner fabric 12, 22;
- b) providing insulation A intended to be arranged between the outer fabrics 11, 21 and inner fabrics 12, 22;
- c) compressing the strips of insulation A corresponding to the ends intended to be in the seams, such that the thickness thereof is reduced;
- d) sewing the edges by means of at least one seam 3 that passes through the outer fabrics 11, 21, the inner fabrics, 12, 22 and the insulation A, such that the seams pass through the compressed strips.
[0049] In other words, to facilitate the production of the bag, object of the present invention, in particular to achieve the seams, the ends which will be in the seam are pressed before sewing, and therefore the sewing process is facilitated, with hardly any effect on the insulation at corners.
[0050] The invention has been explained in relation to a bag with a capacity of 35 to 40 liters and with the shapes shown in Figures 1, 7, 8 or 9.
[0051] However, it may be applied to many other forms, such as a "flatter" form, for example, for a bag for transporting pizzas.
1. An isothermal bag, made up of a containing part (P) and a cover (T), the containing
part (P) being made up of walls (1, 2) joined together by at least one seam (3) and
formed by an outer fabric (11, 21), an inner fabric (12, 22) and an insulation (A)
arranged between the outer fabric (11, 21) and the inner fabric (12, 22), characterized in that the seam (3) passes through the outer fabric (11, 21), the inner fabric (12, 22)
and the insulation (A).
2. The isothermal bag according to claim 1, wherein a front wall (P1), a rear wall (P3),
two lateral walls (P2, P4) and a bottom (F) are defined.
3. The isothermal bag according to claim 2, wherein the front wall (P1) and rear wall
(P3) comprise additional insulation (A2) which has greater rigidity than the insulation
(A) of the lateral walls (P2, P4).
4. The isothermal bag according to claim 3, wherein the additional insulation (A2) of
the front wall (P1) and rear wall (P3) is extruded polystyrene, an aerogel blanket,
wrapped or unwrapped, or a vacuum insulated panel (VIP).
5. The isothermal bag according to any of the preceding claims, wherein the seams (3)
comprise a lining on the edges (4).
6. The isothermal bag according to claim 2, wherein the insulation (A) of the front wall
(P1), rear wall (P3) and lateral walls (P2, P4) is a single piece.
7. The isothermal bag according to any of the preceding claims, wherein the outer fabric
(11, 21) and the inner fabric (12, 22) are nylon.
8. The isothermal bag according to any of the preceding claims, wherein the insulation
(A) is a flexible foam, preferably polyethylene foam.
9. The isothermal bag according to any of the preceding claims, wherein the cover (T)
is a continuation of one of the walls.
10. The isothermal bag according to any of the preceding claims, wherein the cover (T)
is extended at the free edges thereof by means of three flaps (T1), the flaps (T1)
and the edges being free from the mouth of the container (P) provided with closure
means (5).
11. The isothermal bag according to claim 10, wherein the closure means (5) are Velcro.
12. The isothermal bag according to claim 2 and any of the dependent claims thereof, comprising
straps (6) joined to the upper and lower edges of the rear wall (P3).
13. The isothermal bag according to claim 2 and any of the dependent claims thereof, comprising
a handle (7) joined to the central part of the upper edge.
14. The isothermal bag according to any of the preceding claims, comprising inner pouches
intended to contain thermal accumulators.
15. The isothermal bag according to claim 2 and any of the dependent claims thereof, wherein
the front wall (P1) and rear wall (P3) have a height comprised between 35 and 45 cm,
a base comprised between 30 and 40 cm and the lateral walls (P2, P4) have a height
comprised between 35 and 45 cm and a base comprised between 20 and 25 cm.