Patent Description:
<CIT> discloses a dual container that can maintain effective heat insulation and reduce a used amount of thermoplastic resin. The dual container has an inner container provided with a tubular barrel portion having a curled portion formed at the upper circumferential edge thereof, and a bottom portion arranged at the lower end of the barrel portion so as to close the lower surface thereof. An exterior sleeve covers the barrel portion so as to form a heat insulating space between the outside of the barrel portion. The exterior sleeve is fixed to the barrel portion. On the outer surface of the barrel portion of the inner container, a plurality of elongated projection portions each of which is made of plastic resin extending elongatedly in the circumferential direction and projecting by <NUM> to <NUM> are arranged in line over the entire circumference in the circumferential direction, at intervals from one another.

<CIT> discloses a double-walled container including an inner sleeve, an outer sleeve and a base. The inner sleeve is positioned within the outer sleeve. A sidewall cavity may be formed between an inner sleeve sidewall and an outer sleeve sidewall. The lower end of the outer sleeve forms an elongated loop located below a lowermost edge of the inner sleeve. A flange may extend from the elongated loop upwardly above the lowermost edge of the inner sleeve and is attached to the inner sleeve. The elongated loop may form a loop cavity. The loop cavity may be in fluid communication with the sidewall cavity.

<CIT> discloses a container with an inner wall and an outer wall wrapped therearound so as to define a double-wall container construction. A plurality of spacer elements are interposed between the inner and the outer walls so as to maintain a minimum thickness of an air space defined therebetween. In normal use conditions, the spacer elements do not contact the inner wall; however, the spacer elements prevent the outer wall from contacting the inner wall during non-standard use conditions.

These prior art containers, however, still leave room for improvement.

According to various aspects disclosed herein, the invention is generally directed to containers, sidewall constructs, and methods, as recited in the independent claims. Further embodiments are recited in the dependent claims.

According to one aspect of the disclosure, a container for containing a fluid comprises a sidewall construct, a closed bottom, and insulating features. The sidewall construct comprises an inner sidewall extending at least partially around an interior of the container, an outer sleeve attached to the inner sidewall, and a cavity defined between the inner sidewall and the outer sleeve. The closed bottom defines a bottom of the interior of the container. The insulating features comprise the cavity and a plurality of annular bands, each annular band of the plurality of annular bands comprises a plurality of spacers and a plurality of gaps separating respective adjacent spacers in a respective annular band, each spacer extends in the cavity from the inner sidewall to the outer sleeve.

According to another aspect of the disclosure, a sidewall construct for forming a fluid container comprises an inner sidewall for extending at least partially around an interior of a fluid container formed from the sidewall construct, an outer sleeve attached to the inner sidewall, and a cavity defined between the inner sidewall and the outer sleeve. The sidewall construct further comprises insulating features comprising the cavity and a plurality of annular bands, each annular band of the plurality of annular bands comprises a plurality of spacers and a plurality of gaps separating respective adjacent spacers in a respective annular band, each spacer extends in the cavity from the inner sidewall to the outer sleeve.

According to another aspect of the disclosure, a method of forming a container for containing a fluid comprises obtaining an inner sidewall and an outer sleeve and attaching the outer sleeve to the inner sidewall to form a sidewall construct with a cavity defined between the inner sidewall and the outer sleeve. The attaching comprises forming insulating features in the sidewall construct, the insulating features comprise the cavity and a plurality of annular bands, each annular band of the plurality of annular bands comprises a plurality of spacers and a plurality of gaps separating respective adjacent spacers in a respective annular band, each spacer extends in the cavity from the inner sidewall to the outer sleeve. The method further comprises forming an interior of the fluid container by positioning the sidewall construct so that the inner sidewall extends at least partially around the interior. The method further comprises positioning a closed bottom relative to the sidewall construct to define a bottom of the interior.

Containers according to the present disclosure can accommodate fluids, e.g., beverages, of different sizes and compositions. For the purpose of illustration and not for the purpose of limiting the scope of the disclosure, the following detailed description describes a container for heated fluids, e.g., coffee or coffee-based products, tea, hot chocolate, cider, soup, etc. It will be understood that the containers described herein can hold cold beverages or room temperature beverages, and can hold at least partially solid food products, without departing from the disclosure.

In this specification, the terms "lower," "bottom," "upper," and "top" indicate orientations determined in relation to fully erected and upright containers. As described herein, containers can be formed from blanks by overlapping multiple portions, panels, and/or end flaps. Such portions, panels, and/or end flaps may be designated herein in terms relative to one another, e.g., "first", "second", "third", etc., in sequential or non-sequential reference, without departing from the disclosure.

<FIG> is a perspective view, and <FIG> is a schematic cross-sectional view, of a fluid vessel or fluid container <NUM> according to a first exemplary embodiment of the disclosure. In one embodiment, the container <NUM> is a cup having the general shape of a truncated cone, with an open top <NUM>, a closed bottom <NUM>, and a sidewall construct <NUM> extending from a bottom edge to a top edge of the container <NUM>. The closed bottom <NUM> and the sidewall construct <NUM> define an interior space <NUM> of the container <NUM> that is for holding fluids, e.g. hot beverages such as tea, coffee, cider, hot chocolate, etc..

In the illustrated embodiment, the sidewall construct <NUM> comprises an annular inner sidewall <NUM> (broadly, "inner wall") and an outer sleeve <NUM> (broadly, "outer wall") attached to the inner sidewall <NUM> such that the sidewall construct <NUM> can be referred to as a double wall structure. As described herein, the container <NUM> includes insulating features in the sidewall construct <NUM> that include radially adjacent spacers <NUM> separated by respective radial gaps <NUM>. The spacers <NUM> can be at least partially formed from an adhesive, such as a hot melt glue or other glue, and can extend from the inner sidewall <NUM> to the outer sleeve <NUM> to adhesively attach the outer sleeve <NUM> to the inner sidewall <NUM>. In one embodiment, the spacers <NUM> can be formed from a different polymeric material.

As discussed further herein, the insulating features of the container <NUM> are arranged such that cost and materials savings can be realized, and so that an insulation profile of the container <NUM> can be selected so as to be enhanced, for example, so that the fluid in the container <NUM> can be maintained at a selected or desired temperature or temperature range, and such that a customer can be provided with a more comfortable surface about which to grasp the container <NUM>.

As shown in <FIG>, the bottom <NUM> of the container <NUM> includes a generally circular bottom panel <NUM> and an annular leg <NUM> foldably connected to and downwardly-depending from the bottom panel <NUM> at a circular line of weakening <NUM>. The annular inner sidewall <NUM> extends upwardly from the bottom panel <NUM> to define the interior <NUM> of the container <NUM>. As also shown, the inner sidewall <NUM> extends downwardly below the bottom panel <NUM> to define a lower edge margin <NUM> thereof, along a portion of which the annular leg <NUM> is adhesively attached to secure the bottom panel <NUM> to the inner sidewall <NUM> and to form the bottom <NUM> of the interior <NUM> of the container <NUM>.

As shown, the lower edge margin <NUM> of the inner sidewall <NUM> extends along the outer surface of the annular leg <NUM>, wraps under a bottom edge or lower edge thereof, and extends upwardly along the interior surface of the annular leg <NUM> toward the bottom panel <NUM>. The lower edge margin <NUM> of the inner sidewall <NUM> can be an at least partially flexible portion of the inner sidewall <NUM> configured to engage the annular leg <NUM>, and can include surface features to facilitate such engagement, for example, an adhesive treatment and/or frictionally-enhancing patterning. As described herein, the portion of the lower edge margin <NUM> of the inner sidewall <NUM> overlying the lower edge of the annular leg <NUM> will define a bottom edge or lower edge <NUM> of the inner sidewall <NUM>. In one embodiment, the lower edge of the annular leg <NUM> can define the lower edge of the coupled inner sidewall <NUM> and the bottom <NUM>. The bottom <NUM> can be secured to the sidewall construct <NUM> in a different configuration without departing from the disclosure.

As shown, an upper portion of the inner sidewall <NUM> is curved or curled to define a top or upper rim <NUM> of the container <NUM> that circumscribes an opening <NUM> in communication with the interior <NUM> of the container <NUM>. The rim <NUM> and/or an upper portion of the container <NUM> can be flanged or otherwise configured to engage a lid or other top container closure structure.

In one embodiment, the bottom <NUM> of the container <NUM> can be integrally formed with the inner sidewall <NUM>, e.g., such that the annular leg <NUM> is integrally formed with the inner sidewall <NUM>, or the bottom <NUM> can be otherwise attached to a portion of the inner sidewall <NUM> by other attachment means, for example, crimping, heat sealing, etc..

In one embodiment, the illustrated configuration of the truncated conical shape of the container <NUM> can be achieved by forming the inner sidewall <NUM> from a flat blank that is folded around a mandrel such that an overlapping seam is provided, and which can be secured, for example, with an adhesive such as glue. The generally truncated conical shape of the sleeve <NUM> can be formed in a similar manner, or can be formed through a different process without departing from the disclosure.

The arrangement of the bottom panel <NUM> and the annular leg <NUM> of the closed bottom <NUM> of the container <NUM> can be formed, in one example, by providing a generally circular blank having an outer periphery that is downwardly folded to provide the annular leg <NUM> that intersects the bottom panel <NUM> at the line of weakening <NUM>. It will be understood that the container <NUM> can have a different configuration and can be formed by other methods and mechanisms without departing from the disclosure.

Still referring to <FIG> and <FIG>, the outer sleeve or sleeve <NUM>, e.g., a wrap or other layer, is disposed in at least partial circumferential engagement with the inner sidewall <NUM> such that the sleeve <NUM> presents an outer surface of the container <NUM> for engagement by a customer, e.g., such that the customer can wrap his or her fingers around a portion of the sleeve <NUM>. The sleeve <NUM> can be formed, for example, from materials that include single layer structures, multi-layer structures (with or without inserts therebetween), corrugated materials, etc..

As shown, the sleeve <NUM> includes an upper edge <NUM> proximate the rim <NUM> and a lower edge <NUM> proximate the lower portion of the inner sidewall <NUM> generally adjacent the bottom <NUM>. As described herein, at least the interface between the sleeve <NUM> and the inner sidewall <NUM> provide insulating features of the container <NUM> that include a cavity <NUM> defined between the inner sidewall <NUM> and the outer sleeve <NUM>. The insulating features of the container <NUM> can also include one or more portions of the inner sidewall <NUM> and/or the sleeve <NUM>.

Referring additionally to <FIG>, a front view of the container <NUM> with the sleeve <NUM> removed is illustrated. As shown, a plurality of annular bands B1, B2, B3, B4, B5, B6, and B7 of adhesive are applied around the circumference of the inner sidewall <NUM> and are positioned between the inner sidewall <NUM> and the outer sleeve <NUM> to attach the outer sleeve <NUM> to the inner sidewall <NUM> and to form the spacers <NUM>. One or more of the annular bands B1, B2, B3, B4, B5, B6, and B7 can be a discontinuous pattern of adhesive such that the bands comprise adhesive that form the spacers <NUM> that each extend from the inner sidewall <NUM> to the outer sleeve <NUM>, and the gaps <NUM> are radially spaced between adjacent spacers <NUM> along the circumferential length of each of the respective bands around the inner sidewall <NUM>. In one embodiment, the gaps <NUM> are sections of each respective band that can be voids, interruptions, or discontinuities of the material that forms the spacers <NUM> along the bands B1, B2, B3, B4, B5, B6, and B7. It will be understood that a different numbers of bands of spacers <NUM> can be provided without departing from the disclosure.

The spacers <NUM>, as shown, can be elongate members, for example, beads, dots, dashes, tracks, trails, and/or other arrangements of material. The spacers <NUM> can be formed of a composite material or polymeric material, such as a hot melt adhesive or other type of adhesive or glue, though the spacers <NUM> could be material other than adhesive and the outer sleeve <NUM> could be attached to the inner wall <NUM> by means other than the annular bands without departing from the disclosure.

In the illustrated embodiment, the spacers <NUM> can provide and/or maintain spacing between the inner sidewall <NUM> and the sleeve <NUM>, and can additionally provide an attachment, e.g., adhesion, between the inner sidewall <NUM> and the sleeve <NUM>. As shown, the spacers <NUM> have a length L1 corresponding to the length of an arc around the circumference of the portion of the inner sidewall <NUM> covered by the spacer <NUM>, with the length L1 extending between respective first and second ends 29a, 29b of a spacer <NUM>. Similarly, the gaps <NUM> have a length L2 corresponding to the length of an arc around the circumference of the portion of the inner sidewall <NUM> corresponding to the location of the gap that is a portion of the corresponding band that is void of the material that forms the spacers <NUM>, with the length L2 extending from a second end 29b to a first end 29a of adjacent spacers <NUM>. In one embodiment, the length L1 can be greater than the length L2. In another embodiment, the length L2 can be greater than the length L1.

The sum of the lengths L2 of respective gaps <NUM> of a respective annular band of spacers <NUM> can correspond to a materials savings of the respective annular band, and by extension, the container <NUM>. Such material savings can be represented as a percentage of the material of a comparative annular band having a continuous spacer (i.e., with substantially no gaps therealong), for example, between about <NUM>% and about <NUM>% of such material, such as <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or other integer or non-integer numbers therebetween. Accordingly, the materials savings of the entire container <NUM> can be determined by the summation of the material corresponding to the respective lengths L2 of all gaps <NUM> in the annular bands B1, B2, B3, B4, B5, B6, B7, and can represented as a percentage of material of a summed comparative set of annular bands having respective continuous spacers as described above.

While the spacers <NUM> and the gaps <NUM> have been shown as having a generally uniform configuration along the container <NUM>, it will be understood that one or more spacers <NUM> and/or gaps <NUM> can have a different configuration without departing from the disclosure.

Still referring to <FIG>, the spacers <NUM> and the gaps <NUM> of the bands B1, B2, B3, B4, B5, B6, B7 are arranged along the inner sidewall <NUM> such that a plurality of fluid pathways F1, F2 are presented around the spacers <NUM> and through respective gaps <NUM> between the upper edge <NUM> of the sleeve <NUM> and the lower edge <NUM> of the sleeve <NUM> (shown with broken lines in <FIG> for reference). While two fluid pathways F1, F2 are illustrated, the configuration of the annular bands B1, B2, B3, B4, B5, B6, B7 provide much more than two possible fluid pathways. The configuration of the fluid pathways F1, F2 can be at least partially defined by the arrangement and relative offset of spacers <NUM> and gaps <NUM> in adjacent bands B1, B2, B3, B4, B5, B6, B7, which can be uniform or non-uniform, such that the fluid pathways F1, F2 can have a substantially linear (e.g., vertical or oblique) or curved configuration. As shown, vertically-adjacent gaps <NUM> are generally offset from one another, though vertically adjacent gaps <NUM> in one or more of the bands B1, B2, B3, B4, B5, B6, B7 can be aligned without departing from the disclosure. In one embodiment, the fluid pathways F1, F2 can follow a substantially torturous or serpentine path. It will be understood that the fluid pathways F1, F2 can be defined around spacers <NUM> through gaps <NUM> that are not necessarily adjacent, e.g., such that fluid pathways F1, F2 can extend at least partially around the inner sidewall <NUM> between one or more of bands B1, B2, B3, B4, B5, B6, B7 before traveling through a vertically-adjacent gap <NUM> without departing from the disclosure.

According to the invention, the configuration of the bands B1, B2, B3, B4, B5, B6, B7 that create the tortious pathways F1, F2 help create resistance to air flow from the cavity <NUM> between the inner sidewall <NUM> and the outer sleeve <NUM>, to the environment outside the cavity <NUM> which helps maintain the temperature of the beverage in the container by reducing the amount of heat transfer from the cavity <NUM> to the atmosphere E (<FIG>).

As shown in <FIG>, a pocket P1 is formed in the cavity <NUM> between the inner sidewall <NUM> and the sleeve <NUM> between the band B1 and the band B2, a pocket P2 is formed in the cavity <NUM> between the inner sidewall <NUM> and the sleeve <NUM> between the band B2 and the band B3, a pocket P3 is formed in the cavity <NUM> between the inner sidewall <NUM> and the sleeve <NUM> between the band B3 and the band B4, a pocket P4 is formed in the cavity <NUM> between the inner sidewall <NUM> and the sleeve <NUM> between the band B4 and the band B5, a pocket P5 is formed in the cavity <NUM> between the inner sidewall <NUM> and the sleeve <NUM> between the band B5 and the band B6, and a pocket P6 is formed in the cavity <NUM> between the inner sidewall <NUM> and the sleeve <NUM> between the band B6 and the band B7. At least the pockets P1, P2, P3, P4, P5, P6 provide insulating gaps or spaces between the inner sidewall <NUM> and the sleeve <NUM>.

In one embodiment, each pocket P1, P2, P3, P4, P5, P6 can have a width measured from the inner sidewall <NUM> to the sleeve <NUM> and at least partially determined by the size of the spacers <NUM>, which also have such width between about <NUM>,<NUM> (<NUM> mils) and about <NUM>,<NUM> (<NUM> mi1s).

The arrangement of the spacers <NUM> and the gaps <NUM> along the inner sidewall <NUM> is such that the gaps <NUM> provides for fluid communication/air flow between the respective pockets at various locations along the container <NUM>. In one embodiment, the fluid pathways F1, F2 comprise one or more of the respective pockets P1, P2, P3, P4, P5, P6.

In this regard, the arrangement of the spacers <NUM> and the gaps <NUM> of the annular bands B1, B2, B3, B4, B5, B6, B7 provide the one or more fluid pathways. The disclosed arrangement of insulating features is such that heat H generated or held by a fluid in the interior <NUM> of the container <NUM> can transfer, for example, through conduction, convection, and/or radiation, through the inner sidewall <NUM> and/or spacers <NUM> into one or more of the pockets P1, P2, P3, P4, P5, P6, and can be released into the external environment E via the one or more fluid pathways, e.g., F1, F2. Such insulating features can maintain the temperature of the fluid inside the container <NUM> by resisting heat transfer from the cavity <NUM> between the inner sidewall <NUM> and the sleeve <NUM> to the atmosphere E while still maintaining a desired surface temperature of the sleeve <NUM> to facilitate grasping by a customer.

Further, in one embodiment, the surface temperature of the sleeve <NUM> can be higher at points along the sleeve <NUM> that are aligned with the spacers <NUM>, for example, due to thermal conduction of heat H through the solid material of the spacers <NUM>, i.e., such that the spacers <NUM> are formed of a thermally-conductive material. Accordingly, regions of the sleeve <NUM> aligned with the gaps <NUM> and/or the pockets P1, P2, P3, P4, P5, P6 present surface regions of lower temperature at which a user can grasp the sleeve <NUM>, for example, by shifting the placement of his or her fingers along the sleeve <NUM> to provide for more comfortable use of the container <NUM>. In this regard, the dimensioning and arrangement of the spacers <NUM> and the gaps <NUM> can be selected to provide a desired thermal profile along the outer surface of the sleeve <NUM> when the container <NUM> is filled with a hot fluid such as tea, coffee, cider, hot chocolate, etc. In one embodiment, the fluid in the container <NUM> can have a temperature up to, including, or greater than about <NUM>° C (<NUM>° F).

The aforementioned reduction in material for forming the annular bands B1, B2, B3, B4, B5, B6, B7 of spacers <NUM> with gaps <NUM> can provide material and cost-saving benefits as compared to annular bands of continuous spacers with no gaps, e.g., by reducing the cost and materials required to form the container <NUM>, and can also provide streamlining in product production and waste management. In addition to or in the alternative, the relative configuration of the spacers <NUM> and the gaps <NUM> can impart desired structural properties to the container <NUM>, for example, by providing a desired pattern of rigidity such that an optimal pattern of flexion is provided to the container <NUM> during use. For example, upon grasping of the sidewall construct <NUM> by a customer, portions of the sleeve <NUM>/inner sidewall <NUM> can bend or flex inwardly into one or more of the gaps <NUM> or pockets P1, P2, P3, P4, P5, P6 to provide a textured or irregular surface configuration to enhance the customer's grip on the container <NUM>. In one embodiment, the rigidity of the container <NUM> can be between about <NUM> kgf and about <NUM> kgf, for example, <NUM> kgf, <NUM> kgf, <NUM> kgf, <NUM> kgf, <NUM> kgf, <NUM> kgf, <NUM> kgf, <NUM> kgf, <NUM> kgf, <NUM> kgf, <NUM> kgf, or other integer or non-integer values therebetween, with the rigidity being the amount of force applied to the container <NUM> to cause bending or flexing of the sidewall construct <NUM>.

In addition to the insulative and materials-saving properties of the container <NUM> described above, the container <NUM> is further provided with a configuration that can realize significant space savings, for example, during storage and transport. Referring additionally to <FIG>, the inner sidewall <NUM> (and the sleeve <NUM> disposed therearound) of the container <NUM>, as shown, have a tapered configuration such that the inner sidewall <NUM> and the sleeve <NUM> extend at an α relative to a vertical centerline CL of the container <NUM>. The arrangement of the inner sidewall <NUM>, the sleeve <NUM>, and the bottom <NUM> can be such that, upon nesting of multiple containers <NUM>, e.g., such that a container <NUM> is at least partially disposed in the interior space <NUM> of a respective container <NUM> below, the bottom edge <NUM> of the inner sidewall <NUM> of the upper container <NUM> contacts the bottom panel <NUM> of the lower container <NUM> before the respective sidewall constructs <NUM> substantially frictionally engage one another. In this regard, uncoupling of the nested containers <NUM> is not substantially inhibited by frictional resistance. Accordingly, such a nested arrangement of containers <NUM> provides significant space savings for the transport and/or storage of multiple containers <NUM> because the interior <NUM> of a respective container <NUM> can be utilized to at least partially receive the sidewall construct <NUM> and bottom <NUM> of a vertically-adjacent container <NUM>. It will be understood that the container <NUM> can have a different configuration and can be formed by other methods and mechanisms without departing from the disclosure.

The containers and/or the blanks that form the containers according to the present disclosure can be, for example, formed from coated paperboard and similar materials. For example, the interior and/or exterior sides of the blanks can be coated with a clay coating. The clay coating may then be printed over with product, advertising, price coding, and other information or images. The blanks may then be coated with a varnish to protect any information printed on the blank. The blanks may also be coated with, for example, a moisture barrier layer, on either or both sides of the blank. In accordance with the above-described embodiments, the blanks may be constructed of paperboard of a caliper such that it is heavier and more rigid than ordinary paper. The blanks can also be constructed of other materials, such as cardboard, hard paper, or any other material having properties suitable for enabling the container to function at least generally as described herein. The blanks can also be laminated or coated with one or more sheet-like materials at selected panels or panel sections.

In accordance with the above-described embodiments of the present disclosure, a fold line can be any substantially linear, although not necessarily straight, form of weakening that facilitates folding there along. More specifically, but not for the purpose of narrowing the scope of the present disclosure, fold lines include: a score line, such as lines formed with a blunt scoring knife, or the like, which creates a crushed portion in the material along the desired line of weakness; a cut that extends partially into a material along the desired line of weakness, and/or a series of cuts that extend partially into and/or completely through the material along the desired line of weakness; and various combinations of these features.

Claim 1:
A container (<NUM>) for containing a fluid, comprising:
a sidewall construct (<NUM>) comprising an inner sidewall (<NUM>) extending at least partially around an interior (<NUM>) of the container (<NUM>), an outer sleeve (<NUM>) attached to the inner sidewall (<NUM>), and a cavity (<NUM>) defined between the inner sidewall (<NUM>) and the outer sleeve (<NUM>); and
a closed bottom (<NUM>) defining a bottom of the interior (<NUM>) of the container (<NUM>),
the container (<NUM>) comprises insulating features comprising the cavity (<NUM>) and a plurality of annular bands (B1, B2, B3, B4, B5, B6, B7), each annular band of the plurality of annular bands (B1, B2, B3, B4, B5, B6, B7) comprises a plurality of spacers (<NUM>) and a plurality of gaps (<NUM>) separating respective adjacent spacers (<NUM>) in a respective annular band, each spacer extends in the cavity (<NUM>) from the inner sidewall (<NUM>) to the outer sleeve (<NUM>) and one or more of the spacers having a width between about <NUM>,<NUM> (<NUM> mils) and about <NUM>,<NUM> (<NUM> mils),
the gaps (<NUM>) of the respective annular bands define a plurality of fluid paths (F1, F2) through the cavity (<NUM>), the respective gaps (<NUM>) of respective adjacent annular bands are offset from one another, at least one fluid path of the plurality of fluid paths (F1, F2) extends from a lower edge (<NUM>) of the outer sleeve (<NUM>) to an upper edge (<NUM>) of the outer sleeve (<NUM>), the cavity is open to an external environment at each of the upper edge of the outer sleeve and the lower edge of the outer sleeve such that the at least one fluid path of the plurality of fluid paths is in communication with the external environment.