Patent Description:
According to one aspect of the present disclosure, a vacuum insulated structure for a refrigerating appliance, includes an inner liner, an outer wrapper coupled to the inner liner and defining an insulating cavity, and an insulation composition disposed within the insulating cavity. The insulation composition includes a plurality of porous walled hollow glass microspheres. The porous walled hollow glass microspheres include a wall defining an interior and an outer surface. The wall further defines a plurality of interconnected pores, wherein the pores are sized in a range of about <NUM>-<NUM> (<NUM>-<NUM>Å).

According to another aspect of the present disclosure, a vacuum insulated structure for a refrigerating appliance, includes an inner liner, an outer wrapper coupled to the inner liner and defining an insulating cavity, and an insulation composition disposed substantially throughout the insulating cavity. The insulation composition includes a plurality of porous walled hollow glass microspheres. The porous walled hollow glass microspheres include a wall defining an interior cavity and an outer surface. The wall further defines a plurality of channels, wherein the channels are sized in a range of approximately <NUM>-<NUM> (<NUM>-<NUM>,<NUM>Å) and fluidly couple an exterior space with the interior cavity.

Like numerals in the description and drawings represent like elements.

The terms "including," "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a. " does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

Referring to <FIG>, aspects of the present disclosure relate to an insulation composition <NUM> for an appliance <NUM>. The insulation composition <NUM> includes a plurality of porous walled hollow glass microspheres <NUM>. The porous walled hollow glass microspheres <NUM> include a wall <NUM> defining an interior cavity <NUM> and an outer surface <NUM>. The wall <NUM> further defines a plurality of interconnected pores <NUM>. The pores <NUM> are sized in a range of about <NUM>-<NUM> (<NUM>-<NUM>,<NUM>Å) and fluidly couple an exterior space E with the interior cavity <NUM>.

Referring to <FIG>, reference numeral <NUM> generally refers to a vacuum insulated structure for the appliance <NUM>. The vacuum insulated structure <NUM> of the present disclosure may be in the form of a vacuum insulated structural cabinet, as illustrated, or a vacuum insulated panel that may be used as an insulation member for the appliance <NUM>. The appliance <NUM> can be in the form of a refrigerating appliance having a refrigeration compartment <NUM> and a freezer compartment <NUM>, as illustrated. The appliance <NUM> can include first and second insulated door assemblies <NUM> and <NUM> for selectively providing access to the refrigeration compartment <NUM> and the freezer compartment <NUM>, respectively. The first and second insulated door assemblies <NUM> and <NUM> can be configured to rotate and/or slide between an open and closed position with respect to the appliance <NUM> to allow for selective access to the refrigeration compartment <NUM> and the freezer compartment <NUM>, respectively.

The appliance <NUM> can have additional components based on the type of appliance, the details of which are not germane to the aspects of the disclosure, examples of which include a controller, user interface, lights, a compressor, a condenser, an evaporator, an ice maker, a water dispenser, etc. The appliance <NUM> can also be in the form of a refrigerating appliance including only a refrigeration compartment, only a freezer compartment, or any various combinations and configurations thereof. For example, in non-limiting examples, the refrigerating appliance can be a bottom mount refrigerator, a bottom mount French door refrigerator, a top mount refrigerator, a side-by-side refrigerator, a four-door French door refrigerator, and/or a five door French door refrigerator. While the vacuum insulated structure <NUM> is described in the context of a refrigerating appliance, it is understood that the vacuum insulated structure <NUM> can be used in a variety of appliances, examples of which include ovens, dishwashers, water heaters, laundry appliances, and any other appliances that may benefit from thermal and/or sound insulation.

The vacuum insulated structure <NUM> can include an inner liner <NUM> coupled with an outer wrapper <NUM> to define an insulating cavity <NUM> of a cabinet body <NUM> of the appliance <NUM>. In some embodiments, a trim breaker <NUM> can be provided for coupling the inner liner <NUM> with the outer wrapper <NUM>, as illustrated. The inner liner <NUM>, outer wrapper <NUM>, and optional trim breaker <NUM>, can be considered a structural wrapper that defines the insulating cavity <NUM>. The insulation composition <NUM>, or core material, is disposed in the insulating cavity <NUM>.

In some aspects, the first and/or second insulated door assemblies <NUM> and <NUM> can include a vacuum insulated structure 38a and 38b, respectively, that includes the insulation composition <NUM> as described with respect to the vacuum insulated structure <NUM>. The structure and/or materials of the inner liner and outer wrapper components of the first and second insulated door assemblies <NUM> and <NUM> defining the insulating cavity within which the insulation composition <NUM> can be housed may be different than those of the body of the appliance <NUM>, and thus are labeled with the suffix "a" and "b. " The first insulated door assembly <NUM> can include a first door inner liner 60a and a first door outer wrapper 64a, which together define a first door insulating cavity 68a. The second insulated door assembly <NUM> can include a second door inner liner 60b and a second door outer wrapper 64b, which together define a second door insulating cavity 68b. The insulation composition <NUM> may be present in one or both of the first and second door insulating cavities 68a, 68b. In some aspects, the insulation composition <NUM> may be the same in the insulating cavity <NUM> and the first and second door insulating cavities 68a, 68b. In other aspects, at least one of the insulating cavity <NUM>, the first door insulating cavity 68a, and the second door insulating cavity 68b may have a different insulation composition <NUM> and/or different insulation material than the other of the insulating cavity <NUM>, the first door insulating cavity 68a, and the second door insulating cavity 68b.

The inner liner <NUM>, outer wrapper <NUM>, optional trim breaker <NUM>, first and second door inner liners 60a, 60b, and first and second door outer wrappers 64a, 64b, can be made from any suitable metal, metal-alloy, and/or polymeric material, and may be the same or different. The inner liner <NUM>, outer wrapper <NUM>, and optional trim breaker <NUM> can be made from materials suitable for maintaining a vacuum within the insulating cavity <NUM> (i.e., maintain a predetermined lower pressure within the insulating cavity <NUM>, relative to ambient pressure). Likewise, when the first and second insulated door assemblies <NUM>, <NUM> include the vacuum insulated structure 38a, 38b, the first and second door inner liners 60a, 60b, and first and second door outer wrappers 64a, 64b can be made from materials suitable for maintaining a vacuum within the respective first and second door insulating cavities 68a, 68b.

While aspects of the insulation composition <NUM> are described with respect to the vacuum insulated structure <NUM> used to form the cabinet body <NUM> of the appliance <NUM>, it will be understood that aspects of the insulation composition <NUM> can be used with one or both of the vacuum insulated structures 38a, 38b of the first and second insulated door assemblies <NUM>, <NUM>, respectively.

Referring now to <FIG> and <FIG>, the insulation composition <NUM> includes the plurality of porous walled hollow glass microspheres <NUM>. The insulation composition <NUM> may further include one or more additives <NUM> intermixed with the porous walled hollow glass microspheres <NUM>. In some examples, the insulation composition <NUM> includes approximately <NUM>-<NUM> wt. % of the porous walled hollow glass microspheres <NUM> and approximately <NUM>-<NUM> wt. % of one or more additives <NUM>, but is not limited to such ratios. For example, the insulation composition <NUM> may include approximately <NUM>-<NUM> wt. % of the porous walled hollow glass microspheres <NUM> and approximately <NUM>-<NUM> wt. % of one or more additives <NUM>. Non-limiting examples of additives <NUM> include opacifiers, colorants, electrical conductivity additives, radiant energy reflectivity additives, infrared absorbing additives, etc. The insulation composition <NUM> may be tightly packed within the insulating cavity <NUM> such that that various porous walled hollow glass microspheres <NUM> of the plurality of porous walled hollow glass microspheres <NUM> are in direct physical contact with at least one other adjacent porous walled hollow glass microsphere <NUM>.

Referring to <FIG>, the porous walled hollow glass microspheres <NUM> include the wall <NUM> defining the interior cavity <NUM>, or interior, an inner surface <NUM> and the outer surface <NUM>. The interior cavity <NUM> is hollow and may be vacant or include a filler material. The filler material may include opacifiers, such as carbon black, colorants, electrical conductivity additives, radiant energy reflectivity additives, infrared absorbing additives, etc. Further, as the interior cavity <NUM> may be evacuated, a pressure within the interior of the porous walled hollow glass microspheres <NUM> may be less than ambient pressure.

The porous walled hollow glass microspheres <NUM> are generally spherical in shape. An outer diameter, Do, of the porous walled hollow glass microspheres <NUM> may be in a range of approximately <NUM>-<NUM>. In some examples, the outer diameter, Do, of the porous walled hollow glass microspheres <NUM> may be approximately <NUM>. However, it is within the scope of aspects described herein for the outer diameter, Do, to be greater than <NUM> or less than <NUM>. Additionally, the wall <NUM> of the porous walled hollow glass microspheres <NUM> may include a thickness of approximately <NUM> (<NUM>,<NUM>Å).

The wall <NUM> defines a plurality of channels <NUM>, which may be in the form of pores, such that the wall <NUM> is porous and includes a high-degree of porosity. In some aspects, the channels <NUM> are interconnected. In this way, various channels <NUM> of the plurality of channels <NUM> are in fluid communication with an adjacent channel <NUM> of the plurality of channels <NUM>. The plurality of channels <NUM> fluidly couple an exterior space, E, with the interior cavity <NUM>. The channels <NUM> may be sized in a range of approximately <NUM>-<NUM> (<NUM>-<NUM>,<NUM>Å) as measured by mercury intrusion porosimetry. This high-degree of porosity of the walls <NUM> permits the interior cavity <NUM> to be evacuated such that the interior cavity <NUM> may be at least partially, or completely evacuated. As such, gas conduction of heat may be reduced. Further, the high-degree of porosity of the walls <NUM> results in a reduction of solid conduction of heat on the walls <NUM> compared to a hollow glass microsphere (HGM), which does not include walls having pores. Therefore, the high-degree of porosity of the walls <NUM> significantly reduces thermal conductivity for increased thermal performance of the insulation composition <NUM>.

Still referring to <FIG>, the wall <NUM> is made of a glass composition <NUM> which is resistant to thermal shock. In some aspects, the glass composition <NUM> is almost entirely SiO<NUM> (silicon dioxide). More specifically, the glass composition <NUM> may be a borosilicate glass having SiO<NUM> and B<NUM>O<NUM> (boric oxide) as the main glass-forming constituents. The glass composition <NUM> may be in the form of a mixture further including, but not limited to: Na<NUM>O (sodium oxide), Li<NUM>O (lithium oxide), CaO (calcium oxide), ZnO (zinc oxide), P<NUM>O<NUM> (phosphorus pentoxide) and Al<NUM>O<NUM> (aluminum oxide). For example, the glass composition <NUM> may include approximately <NUM>-<NUM> wt. % SiO<NUM>, approximately <NUM>-<NUM> wt. % B<NUM>O<NUM>, approximately <NUM>-<NUM> wt. % Na<NUM>O, approximately <NUM>-<NUM> wt. % Li<NUM>O, approximately <NUM>-<NUM> wt. % CaO, approximately <NUM>-<NUM> wt. % ZnO, approximately <NUM>-<NUM> wt. % P<NUM>O<NUM>, and approximately <NUM>-<NUM> wt. % Al<NUM>O<NUM>. The glass composition <NUM> may include additives other than those previously listed. For example, the glass composition <NUM> itself may include opacifying properties due to additives, such as transition metal oxides (TMOs), including, but not limited to: oxides of manganese, iron, cobalt, copper, nickel, etc. In other examples, the glass composition <NUM> can include: colorants, electrical conductivity additives, radiant energy reflectivity additives, infrared absorbing additives, etc..

The insulation composition <NUM> containing porous walled hollow glass microspheres <NUM> can be used to address several challenges associated with forming vacuum insulated structures. In some aspects, insulation composition <NUM> provides sufficient mechanical strength while also having desired thermal performance. Traditional hollow glass microspheres may include sufficient mechanical strength while thermal performance may be reduced due to the solid nature of the walls. The insulation composition <NUM> can be configured to inhibit or decrease vacuum bow (deformation of the inner liner <NUM> and outer wrapper <NUM> during evacuation) as the insulation composition <NUM> may have a high flowability and high mechanical strength due to the nature of the porous walled hollow glass microspheres <NUM>. Accordingly, insulation composition <NUM> provides a vacuum insulated structure having a thermal conductivity and mechanical strength suitable for use in a refrigeration appliance, which is configured to inhibit or decrease vacuum bow.

<FIG> illustrates a non-claimed method <NUM> for forming porous walled hollow glass microspheres <NUM> according to aspects of the present disclosure. The method <NUM> can be used to form porous walled hollow glass microspheres <NUM> for use in the insulation composition <NUM> of <FIG>, however it is within the scope of the disclosure for the porous walled hollow glass microspheres <NUM> to be formed using any suitable method(s).

The method <NUM> of <FIG> includes melting a glass composition, such as the glass composition <NUM> (in a raw form), or the constituents of the glass composition <NUM>, at step <NUM>, thereby forming a frit material at step <NUM>. Optionally, the method <NUM> can include a size reduction process to reduce the coarseness of the frit material. At step <NUM>, the frit material is sized such that particles having similar sizes are collected. Step <NUM> may include a screening technique such that undersized particles are separated out and may be collected for re-use. A series of screening steps can be employed to produce frit particles having a controlled, or desired, size. Once the frit material has been sufficiently sized, a flame process is performed at step <NUM> to transform the frit particles into a spherical shape. The flame process may consist of spraying the frit material with a blowing agent into a gas-fueled flame. This rapid heating transforms the frit particles into the spherical shape, and, in time, a cavity is formed that can continue to expand during the flame process. This results in the formation of traditional hollow glass microspheres at step <NUM>. Optionally, the method <NUM> can include a sizing process to separate the hollow glass microspheres by diameter, or size.

In order to convert the hollow glass microspheres into porous walled hollow glass microspheres <NUM>, the method <NUM> continues at step <NUM> with a heat treatment procedure. The heat treatment procedure separates the glass composition of the hollow glass microspheres into two glass phases. One glass phase is chemically stable and another glass phase is extractable, such that it may dissolve in acid. At step <NUM>, an acid leach process is executed where the extractable phase is leached from the chemically stable phase, thereby forming pores, or channels. For the acid leach process, any suitable strong mineral acid may be used, including hydrochloric acid (HCl). Step <NUM> results in the formation of the porous walled hollow glass microspheres at step <NUM>. The method <NUM> may include one or more microscopy steps at any suitable point during the process to view samples for ensuring quality control.

<FIG> illustrates a non-claimed method <NUM> for forming a vacuum insulated structure <NUM> containing the insulation composition <NUM> according to aspects of the present disclosure. The method <NUM> can be used to form an insulation composition <NUM> for use in the vacuum insulated structures <NUM>, 38a, and/or 38b of <FIG>, and any other vacuum insulated structure suitable for use in insulating an appliance.

The method <NUM> of <FIG> includes providing the insulation composition <NUM> at step <NUM>. The plurality porous walled hollow glass microspheres <NUM> can be formed according to any suitable process, including, but not limited to, the method <NUM>. The plurality of porous walled hollow glass microspheres <NUM> can be intermixed with the additives <NUM>, if present, in a desired ratio as previously discussed. The inner liner <NUM> can be sealed with the outer wrapper <NUM> at step <NUM> such that the walls of the inner liner <NUM> are spaced from the adjacent walls of the outer wrapper <NUM> to form the insulating cavity <NUM>. The trim breaker <NUM> can be coupled with the open ends of the inner liner <NUM> and the outer wrapper <NUM> to seal the insulating cavity <NUM>. Sealing the inner liner <NUM>, outer wrapper <NUM>, and optional trim breaker <NUM> can include any suitable combination of welds, adhesives, gaskets, seals, and/or connecting structures.

In other examples, the vacuum insulated structures <NUM>, 38a, and/or 38b can be in the form of individual vacuum insulated panels having an inner liner and an outer wrapper defining an insulating cavity including the insulation composition <NUM>. These vacuum insulated panels can then be inserted within the insulating cavity <NUM> of the cabinet body <NUM>, first insulated door insulating cavity 68a, and/or second insulated door insulating cavity 68b, respectively.

Claim 1:
A vacuum insulated structure (<NUM>) for a refrigerating appliance (<NUM>), comprising:
an inner liner (<NUM>);
an outer wrapper (<NUM>) coupled to the inner liner (<NUM>) and defining an insulating cavity (<NUM>); and
an insulation composition (<NUM>) disposed within the insulating cavity (<NUM>), the insulation composition (<NUM>) comprising a plurality of porous walled hollow glass microspheres (<NUM>), the porous walled hollow glass microspheres (<NUM>) comprising a wall (<NUM>) defining an interior (<NUM>) and an outer surface (<NUM>), the wall (<NUM>) further defining a plurality of pores (<NUM>),
characterised in that the pores (<NUM>) are interconnected and are sized in a range of about <NUM>-<NUM> (<NUM>-<NUM>Å).