Capsule with expandable chamber

Abstract

The present invention relates to a capsule (100) characterized by being subdivided into at least two chambers, wherein at least one expandable chamber (101) and at least one retractable chamber (103) are separated by at least one flexible membrane (102). There is also the possibility of having at least one pressure relief hole (104) in the retractable chamber (103). This invention addresses two distinct challenges: the controlled positioning of a material contained within the interior of an expandable chamber (101), and the ability to more efficiently contain materials that expand and contract, generating volume variations and consequent changes in a internal pressure of the capsule (100) without altering its external geometry or compromising its integrity.

Description

CAPSULE WITH EXPANDABLE CHAMBER

[0001] This invention relates to a capsule which, due to its internal geometry, allows substances to be contained in an exact and desired position, regardless of the positioning or orientation of the capsule when included in any system. Furthermore, the capsule allows, due to the presence of an internal flexible membrane, the accommodation of predetermined materials within its internal geometry that are subject to volume changes and / or the self-regulation of the capsule’s internal pressures without altering its external geometry. In this way, the use of this capsule can prevent catastrophic failure such as bursting or leaking of any material contained inside when it is subjected to volume or pressure changes due to external factors such as temperature variations. It is also characteristic of this capsule to be produced as a single piece, using a combined process of 3D printing and simultaneous filling.

[0002] Document US20220243998A1 discloses 1) the use of a 3D printing system capable of depositing polymer filament that contains a PCM (Phase Change Material) core, and 2) discloses the design of geometries created through simultaneous extrusion, by a single nozzle, of two distinct and differentiated materials (polymer and PCM), resulting in a design with a polymer shell and a PCM core, with the aim of producing macrocapsules containing PCM for incorporation into temperature conditioning / thermal control systems. The invention disclosed in the present document differs from document US20220243998A1 in that the latter proposes a PCM-embedded filament and a 3D printing method using a combined tool to create PCM macrocapsules and fill them simultaneously. The invention disclosed in this document aims to protect a configuration of a capsule that, regardless of its external geometry, contains internal chambers that allow the precise positioning of the material it holds, such as PCM, and that compensate for possible internal variations in volume and pressure of the material contained in the capsules.

[0003] Document US8683803B2 discloses an apparatus and a method for generating energy, using PCM and a mechanism that involves an expandable chamber that moves according to the phase change of the PCM, thereby generating energy. The invention disclosed in this document differs from document US8683803B2 in that the latter refers to a complex mechanical system that uses PCM and an expandable chamber to generate energy, whereas the patent disclosed in the present document seeks to protect a single-component capsule with an expandable chamber, intended to encapsulate materials such as PCM, while maintaining the positioning of said material and compensating for possible variations in internal volume and pressure without compromising the integrity of the capsule.

[0004] The technical problems that this invention addresses are: 1) to precisely control the positioning of the material contained within the chambers of the capsule, making the material’s position unaffected by the state of matter said material is at and the effects of gravity, and 2) to compensate for possible increases in volume and internal pressure generated inside the chamber where the encapsulated material is located, in order to ensure the integrity and usability of the capsule, and 3) eliminate the need for the chamber to be partially filled with air, allowing for the expandable chambers to be fully filled with the desired material, increasing performance of the thermal system.

[0005] There are numerous situations where it is necessary to encapsulate materials in order to contain them within a space so that they do not spill or interfere with other substances or components in a given system. One example is the encapsulation of phase change materials (PCM, from the English phase change materials). To be useful and fulfill their function of thermally regulating systems that require temperature conditioning, PCMs, as the name indicates, change phase, most commonly from liquid to solid and vice versa. Therefore, it is necessary to contain them within a closed space so that there is no mass loss of the PCM. However, this needs to enclose the PCM raises several challenges, as the phase changes generate volume variations and, consequently, pressure variations inside the capsules that contain them. Taking this into account, several consequences may occur. For example, if the pressure exceeds the mechanical limits of the capsule, it may become deformed or fail and leak its internal contents. Another possible consequence, if there is no way for the PCM to expand, is that the phase change may not occur, as a pressure so high is created inside the capsule that the PCM may be unable to change phase, or else it alters the conditions under which it changes phase, such as the melting temperature. Thus, the PCM changes its physical state within an atypical and unknown temperature range, compromising its applicability and jeopardizing the proper functioning of the system in which it is integrated.

[0006] The objective of the present invention is to disclose the use of chambers created by flexible membranes inside a rigid capsule, said chambers may comprise any type of material within it in specific positions, which enable the self-regulating internal pressure increases that the capsule may experience due to external factors such as temperature changes that expand or contract the material retained in the chambers of the capsule.

[0007] This capsule is intended for use in containing any type of material, whether in solid or liquid state, such as phase change materials (PCM), forming macrocapsules that can be embedded in energy systems for temperature regulation, with the benefit of increasing the longevity of the capsules and enabling precise control over the positioning of the material, thereby increasing the potential to further optimize the systems and enhance their efficiency. A practical case of the usefulness of this technology is the encapsulation of PCM.

[0008] The present invention describes a capsule to support and surround a section of a thermal system, comprising one side surface that partially fits and surrounds said thermal system, being characterized by comprising internally at least one expandable chamber and at least one retractable chamber, said chambers being separated by flexible membranes.

[0009] In a proposed embodiment of present invention, the at least one expandable chamber comprises material such as PCM, air, or other adequate with a thermal expansion coefficient greater than 1×10-3°C-1.

[0010] Yet in another proposed embodiment of present invention, the at least one retractable chamber comprises at least one pressure relief hole.

[0011] Yet in another proposed embodiment of present invention, the capsule comprises a combination of polymer families, derivatives, and respective fiber-reinforced composites like: polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), polyamide (PA), polysulfone (PSU), polyphenylene sulfide (PPS), polypropylene (PP), polycarbonate (PC), polycyclohexylene dimethylene terephthalate (PCTG), polyaryletherketone (PAEK), polyetherimide (PEI), polyvinylidene fluoride (PVDF), and polystyrene (PS).

[0012] Yet in another proposed embodiment of present invention, the combination of polymer families, derivatives, and respective fiber-reinforced composites are integrated into a single piece or in multiple interlocked pieces with the polymers used in the various constituents of the capsule fused together, forming sealed cavities.

[0013] The current invention also teaches about a method of production of the capsule which comprises a combined Fused Deposition Modeling process of 3D printing of additive manufacturing of multiple polymers with simultaneous filling of the chambers with different materials in its various chambers.General Description of the Invention

[0014] The present invention concerns a capsule with multiple internal chambers, some of which are expandable, bounded by flexible membranes, making it possible to store any materials, such as PCM materials, within these internal chambers. These characteristics enable a well-defined positioning of the encapsulated material, without compromising either the external geometry of the capsule or its mechanical integrity when subjected to external conditions that cause the materials stored in the internal chambers to expand or contract.

[0015] A flexible membrane may be understood as any geometry such as simple flat walls, diaphragms, bladders, or complex foldable geometries, as long as they fulfil the function of being an internal structural element of the capsule, said membrane being flexible and / or deformable so as to accommodate volume changes from the chambers, without compromising the physical integrity of the capsule, and without leaking its contents comprised within said chambers.

[0016] For explanatory purposes, but without in any way limiting the geometry of the capsule or the type of system into which it can be incorporated, this document demonstrates one possible geometry of the capsule inserted into a system that allows the exploitation of the capsule’s capabilities.

[0017] The preferred production method of this capsule is the additive manufacturing with simultaneous filling of the chambers, and it may be composed of multiple polymers and contain different materials in its various chambers.

[0018] Some advantages of the present invention include: - Precise positioning of materials incorporated within the capsule expandable chamber. - Regulation of internal pressure of the capsule, in particular, of the internal capsule expandable and retractable chambers. - Increased the longevity of the capsule. - Incorporation of multiple materials in the structure of the capsule without mixing. - Preserving the external geometry of the capsule.

[0019] For easier understanding of the invention, the following figures represent preferred embodiments of the invention, which are not intended to limit the scope of the present invention.

[0020] illustrates a sectional view of the proposed capsule (100) with an internal flexible membrane (102) in a relaxed state.

[0021] illustrates a sectional view of the proposed capsule (100) with the internal flexible membrane (102) in an expanded state due to the pressure and expansion of the material (or air) inside the expandable chamber (101).

[0022] illustrates an isometric view of a tubular thermal system (200) being involved by two of the proposed capsules (100).

[0023] As illustrated in, the present invention describes a capsule (100) which comprises an internal expandable chamber (101), bounded by a flexible membrane (102), which enables the storage of various materials within said internal chambers (101) in a well-defined position. Due to the deformability of the flexible membrane (102), it becomes possible to store materials, preferably PCM materials (or air), under conditions that may cause their volume to increase or decrease. This is possible due to the existence of a retractable chamber (103) which, through pressure relief holes (104), is capable of relieving internal pressure increases inside the capsule (100), maintaining its mechanical integrity and preserving its external geometry.

[0024] In a possible embodiment of the invention, as illustrated throughout the figures, the capsule comprises a external geometry (squared in the provided example) with one side surface (concave in the provided example), more rigid than the flexible membrane (102) comprised within the interior of the capsule (100). The illustrated example proposes a squared external geometry, but other geometries can be considered. The side surface of the external geometry is meant to, partially or totally, fit or adapt to a thermal system (200). The illustrated example proposes a tubular thermal system, but other geometries can be considered. The concave side of the external geometry can, thus, have any other shape that allows it to partially or totally fit or adapt to a thermal system. The flexible membrane (102) is comprised within the interior of the capsule (100), and in the preferred illustrated embodiment, is positioned parallelly to side surface of the external structure that partially surrounds the section of the thermal system (200). In, the flexible membrane (102) is in a normal, original relaxed state, since the encapsulated material, air or vacuum, contained within the expandable chamber (101), created by the space between the external structure of the capsule (100) and the flexible membrane (102), is not under any form of temperature pressure or stress, nor volume increase. On the other hand, in, the material contained within the expandable chamber (101) is under pressure due to the increase of volume the material (or air) therein comprised, which leads the flexible membrane (102) to deform and expand due to the material volume expansion, occupying a portion of space of the retractable chamber (103), said chamber (103) decreasing its interior hollow available volume, which lead to a release of air through the pressure release hole (104). In both illustrations of Figures 1 and 2, the size and volume of the expandable chamber (101) and retractable chamber (103) may vary, and may hollow, just comprising air.

[0025] The capsule (100) may contain multiple expandable chambers (101), retractable chambers (103), flexible membranes (102), and incorporated pressure relief holes (104).

[0026] A flexible membrane (102) is defined as any type of internal wall that: a) has low stiffness, thus being elastic and deformable, either due to its geometric properties (such as thickness or shape) or due to material properties, and / or b) changes its geometry when subjected to any type of mechanical force. A flexible membrane (102) may be any geometry such as simple flat walls, diaphragms, bladders, or complex foldable geometries, among others, as long as it fulfills the function of being a structural element that bounds an expandable chamber (101) of the capsule and is flexible and / or deformable in order to accommodate volume changes in the expandable chambers (101) caused by internal pressure increases due to the expansion or contraction of the embedded materials, preferably PCM materials, without compromising the physical integrity of the capsule or leaking its contents.

[0027] An expandable chamber (101) is defined as any chamber belonging to the capsule (100), bounded by one or more flexible membranes (102), whose function is to contain the encapsulated material.

[0028] A retractable chamber (103) is defined as any chamber whose purpose is to act as a buffer, redistributing and absorbing the effects of pressure from the expansion of the expandable chambers (101). The expandable chamber (101) may also be under vacuum or contain compressible materials such as air, among others.

[0029] A pressure relief hole (104) is defined as one or more holes in the retractable chamber (103) that aim to relieve the pressure of the retractable chamber (103).

[0030] A thermal system (200) is defined as any system that requires thermal regulation, in any of its forms (convective, radiative or through conduction), in which this type of capsule (100) can be applied.

[0031] Capsules (100) such as the one illustrated this become attractive for the encapsulation of materials such as PCM (phase change materials), as they allow absorption of the cyclic volume variations and the resulting pressure variations that arise from the phase changes of these materials during their operating cycle in thermal systems.

[0032] The capsule described in this invention description has as its ideal manufacturing process multimaterial 3D printing, combined with the simultaneous filling of the capsule. In this way, it is possible to create a multimaterial capsule as a single piece, with various types of polymers fused into one component (for example, using a rigid polymer for the outer shell of the capsule and a flexible polymer for the flexible membrane (102)). Combining the various elements of the invention described in this document favors sealing and reduces production complexity compared to an alternative that would require the assembly of multiple components by screwing or gluing. In addition, combining the various components that make up the invention into a single piece eliminates the need for maintenance. Taking into account the inherent benefits of the chamber system previously described in this document, along with the advantages of the ideal production process of the capsule and the integration of its components into a single piece, it allows for a theoretical 100% volume occupancy rate of PCM (or any other material contained within the capsule), eliminating the presence of thermal barriers due to residual air inside the expandable chamber (101), which would otherwise reduce system efficiency.

[0033] Some examples of polymers, polymer families, derivatives, and associated composites (such as carbon fiber and fiberglass infusions, for example) that may be used in the manufacture of these capsules include: polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), polyamide (PA), polysulfone (PSU), polyphenylene sulfide (PPS), polypropylene (PP), polycarbonate (PC), polycyclohexylene dimethylene terephthalate (PCTG), polyaryletherketone (PAEK), polyetherimide (PEI), polyvinylidene fluoride (PVDF), and polystyrene (PS).

[0034] The capsule (100) is designed and recommended to be manufactured through FDM (Fused Deposition Modeling) 3D printing technologies, but not exclusively using this type of technology. The use of this technology allows the capsule’s (100) structure to be produced in a single component, where the material that comprises the external rigid structure of the multiple expandable chambers (101) of the capsule to fuse with the material that comprises the flexible membrane (102). Furthermore, in a scenario where the material that comprises the expandable chamber (101) is not compatible with the material that comprises the flexible membrane (102), both components may be mechanically interlocked with design features where the wall / shell of the expandable chamber (101) encompasses protrusions of the flexible membrane (102) or vice versa, resulting in a sealed system capable of embedding other materials in any physical state.

[0035] As previously mentioned, the flexible membrane (102) may possess flexible properties (i.e., the ability to deform easily to allow the expansion of the material it encapsulates, attenuating high pressure increases) that result from three distinct factors, namely: 1) the membrane’s thickness, 2) the membrane’s geometry, and 3) the material from which the membrane is made. 1) Regarding the thickness of the membrane (102) (>0.01mm): the thinner the membrane (102), the more easily it deforms, requiring less force to do so, regardless of the material’s stiffness. For this reason, it is possible to produce a capsule (100) with the characteristics presented using a single polymer. 2) Regarding the geometry of the membrane (102): the membrane may have a complex structure with multiple joints / flex points that allow it to be foldable when subjected to pressure or temperature, as in the case of materials with shape memory or origami-like behavior. In this way, the membrane can expand and contract as needed, regardless of the material used. 3) Regarding the material of the membrane (102): more flexible polymers such as TPU and TPE may be used to facilitate the deformation of the capsule.

[0036] The three parameters above-mentioned, isolated or combined, when used together with a more rigid shell (in the same line of thought), rigidity provided by a more rigid material – such as PETG or PPS –, a thicker shell or more robust geometry, can be used to produce components of the capsule such as the expandable chamber (101), having the possibility of comprising multimaterial capsules produced as a single piece with variable inner geometries / properties.Application Examples

[0037] 1) Capsules such as this become especially attractive for the encapsulation of materials that, during their use, exhibit significant volume changes, such as—but not limited to phase change materials (PCM). These capsules allow absorption of the cyclic volume variations and resulting internal pressure changes that occur during the phase transitions of these materials throughout their operation in thermal systems.

[0038] 2) Beyond PCM, these capsules are ideal for encapsulating materials subjected to large thermal amplitudes, which cause their volume to vary solely due to heating or cooling, without undergoing a phase change, due to their high thermal expansion coefficients (greater than 1×10-3°C-1).

[0039] 3) Capsules such as this can be embedded in a wide variety of thermal systems (200), increasing its thermoregulatory efficiency. They offer two major advantages: a) when encapsulating certain materials—specifically materials that undergo volume changes, such as the previously mentioned PCM—cyclic pressure variations are generated inside the capsules (101); b) they allow precise positioning of where the PCM is stored. Due to the effect of gravity, within any capsule, the material it contains will always settle at the bottom of the capsule, leaving any less dense material, usually air, to occupy the upper part of the capsule's interior. In thermal systems (200) like the one shown in, the capsule (100) located above the thermal system (200) presents no constraints, since the material embedded in the capsule (100) is immediately in contact with the boundary of the capsule (100) that directly surrounds the thermal system (200) through its concave external geometry side. However, when it comes to a generic capsule in that same position, bellow the thermal system (200), gravity causes the material embedded in the capsule to settle down, accumulation in the bottom of the capsule, and the air to rise, creating a thermal barrier between the embedded material and the side surface of the capsule that directly contacts the thermal system, reducing heat transfer and, consequently, the system’s response speed. With the use of a capsule (100) as herein described, thanks to the precise positioning of the material embedded in the expandable chamber (103), bounded by the flexible membrane (102), the embedded material can remain in direct contact with the surface of the capsule (100) that directly surrounds the thermal system (200), increasing heat transfer and directly improving the thermal efficiency of the system.

[0040] 4) The subject matter described above is provided as an embodiment of the present invention and should not be interpreted as limiting it. The terminology used to describe specific embodiments according to the present invention should not be interpreted to limit the invention.

[0041] 5) It will be understood that the term "comprises," when used in this description, specifies the presence of the features, elements, components, steps, and operations referred to, but does not exclude the possibility of the presence of other features, elements, components, steps, and operations.

[0042] 6) The invention should in no way be considered limited to the described embodiments, and a person skilled in the art will foresee many possibilities for modifications thereof.

[0043] 7) The embodiments described above are combinable.

[0044] 8) The following claims further establish particular embodiments of the invention.

[0045] 100 – Capsule

[0046] 101 – Expandable chamber

[0047] 102 – Flexible membrane

[0048] 103 – Retractable chamber

[0049] 104 – Pressure relief hole

[0050] 200 – Thermal system

Claims

Capsule (100) to support and surround a section of a thermal system (200), comprising one side surface that partially fits and surrounds said section of the thermal system (200), being characterized by comprising internally at least one expandable chamber (101) and at least one retractable chamber (103), said chambers (101, 103) being separated by flexible membranes (102).Capsule (100) according to previous claim 1, characterized by the at least one expandable chamber (101) comprising material such as PCM, air, or other adequate with a thermal expansion coefficient greater than 1×10-3°C-1.Capsule (100) according to previous claim 1, characterized by the at least one retractable chamber (103) comprising at least one pressure relief hole (104).Capsule (100) according to any of the previous claims, characterized by comprising a combination of polymer families, derivatives, and respective fiber-reinforced composites like: polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), polyamide (PA), polysulfone (PSU), polyphenylene sulfide (PPS), polypropylene (PP), polycarbonate (PC), polycyclohexylene dimethylene terephthalate (PCTG), polyaryletherketone (PAEK), polyetherimide (PEI), polyvinylidene fluoride (PVDF), and polystyrene (PS).Capsule (100) according to the previous claim, characterized by the combination of polymer families, derivatives, and respective fiber-reinforced composites being integrated into a single piece or in multiple interlocked pieces with the polymers used in the various constituents of the capsule fused together, forming sealed cavities.Method of production of the capsule (100) according to any of the previous claims, comprising a combined Fused Deposition Modeling process of 3D printing of additive manufacturing of multiple polymers with simultaneous filling of the chambers (101, 103) with different materials in its various chambers (101, 103).

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