WO2006005002A2

WO2006005002A2 - Insulated vessel

Info

Publication number: WO2006005002A2
Application number: PCT/US2005/023496
Authority: WO
Inventors: Cheryl R.P. Kull; Michael Walden
Original assignee: Kull Cheryl R P; Michael Walden
Priority date: 2004-06-30
Filing date: 2005-06-29
Publication date: 2006-01-12
Also published as: WO2006005002A3

Abstract

An insulated vessel is disclosed. The vessel includes an outer shell (11) with an opening (12) having an area substantially smaller than the maximum area of a normal section of the outer shell. An inner liner (14) of having a maximum area of a normal section of the inner liner that is substantially greater than the area of the opening of the outer shell is disposed inside the outer shell. Insulation is provided in the space between the outer shell and the inner liner.

Description

INSULATED VESSEL

RELATED APPLICATIONS

This application is a corresponding non-provisional application of US Provisional Patent Application no. 60/584,363, filed on June 30, 2004.

FIELD OF THE INVENTION

This invention relates to insulated vessels for consumable materials such as teapots, soup tureens or similarly shaped containers made of moldable material such as ceramic or porcelain and a method of producing the same.

BACKGROUND OF THE INVENTION

Typical vessels for serving food or beverages such as teapots, tureens and the like have a typical somewhat spherical shape with an opening at the top. The advantage of the somewhat spherical (spheroid) shape is that it approximates a sphere, and a sphere is the most efficient shape in terms of its volume to surface area ratio. These vessels are generally of single wall construction, made of various materials, such as glass, ceramic, plastic, and metal. One of the drawbacks of the single wall construction is that such vessels are not efficient in maintaining the temperature of the contents. There are a few teapots that are composed of an inner and outer chamber, insulated by some material that acts to trap or reflect back the heat of the inner chamber. There are also some teapots that have an inner glass or metal, two walled vacuum chamber within an outer protective shell or case. This construction is of the best design to retain heat over a long period of time, hi some instants the vacuum chamber may be made of metal, but this design is not as effective as the glass design. In either of the two latter designs, the physical design of the vessel appears much like a tall and narrow pitcher for reasons of cost and efficiency of heat retention.

For example, US Patent No. 4,595,437 (Yamamoto, June 17, 1986) discloses a ceramic or porcelain composite vessel with an airtight hollow chamber under reduced pressure. The composite vessel is formed from an inner vessel and an outer vessel. The hollow chamber is maintained airtight by an enamel bonding of the inner and outer vessel. The reduced pressure in the hollow chamber is produced by heating. The vessels disclosed in the Yamamoto patent include an inner and outer vessel that are characterized by the outer vessel having an opening with a diameter that is greater than the maximum external diameter of the inner vessel. Consequently, the vessel shapes derived for the method described are not the elegant, substantially spheroid teapot shapes desired by many consumers that have the added benefit of providing the more efficient volume to surface area ratio.

SUMMARY OF THE INVENTION

The present invention provides a vacuum insulated vessel with the desired aesthetic shape and functional volume to surface area characteristics found in classical teapots. The vessel includes an outer shell having an external surface; an internal surface and an outer shell opening having an area that is substantially smaller than the maximum area of a normal section of the external surface of the outer shell. The vessel further includes an inner liner disposed inside the outer shell, said inner liner having an external surface, an internal surface and a liner opening having an area that is substantially smaller than the maximum area of a normal section of the external surface of the liner, said liner opening being of substantially the same shape and dimension as the outer shell opening. Means are provided for drawing a vacuum in the space between the outer shell and inner lining.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a cross-sectional view of a vessel of the present invention.

Fig. 2 is an illustration of a cross-section of an exemplary structure for joining the outer shell and inner liner in accordance with the invention

Fig. 3 is an illustration of a cross-section showing an alternate structure for the vessel of the invention.

Fig. 4 is an illustration of an alternate embodiment of an insulated vessel having a plurality of vacuum form inserts.

Fig. 5 is an illustration of a cross-section of a vacuum form insert. Fig. 6 illustrates a vessel 10 in the form of a teapot with a spout.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Fig. 1 illustrates the structural elements of a vessel 10, such as a tea pot, of one embodiment of the present invention. The vessel 10 includes an outer shell 11 having at least a portion of spheroid shape and including an opening 12 with a maximum dimension dl and a substantially flat bottom 13 that serves as a base for the vessel 10. In the case of a circular opening the dimension dl would be the diameter of the opening. The vessel also includes an inner liner 14 having at least a portion of spheroid shape As better illustrated in Fig.2, the inner liner 14 of the teapot is an integral component, with an air tight seal at the intersection of the inner liner and the outer shell 11. In the embodiment illustrated in Fig. 1 and 2 the inner liner 14 is supported by a portion of the outer shell 11. The inner liner 14 is designed and sized to fit within the outer shell and to provide a space 15 between the outer surface of the inner liner 14 and the inner surface of the outer shell 11 and has an external dimension d2 that is substantially larger than the opening 13 with dimension dl . The airtight seal between the inner liner 14 and the outer shell 11 provides the ability to draw down a vacuum between the inner liner and the outer shell. The vacuum insulates the inner liners hot contents from the outer shell, so as not to lose any heat to the surrounding environment.

The shape of the vessel 10 may be of any spheroid shape with pleasing aesthetics. For example, a vessel in the form of a teapot may have the characteristic and distinctive shape of a conventional English teapot. Alternately, it may have the shape of any of the various ethnic configurations, such as French, Chinese, Japanese, etc. The spheroid shape is desirable because a sphere has the lowest surface-to-volume ratio of any geometric solid. In addition, spheroid shapes in containers tend to maximize the strength of the container. Since spheroid shapes tend to minimize the surface area of a container for the volume of liquid contained, the shape minimizes the rate of heat transfer since the rate of heat transfer is dependent on the area that contacts the liquid. Although the embodiment described above makes use of certain advantages of spheroid shapes, it should be noted that the invention is not limited to spheroid shapes. Any vessel having an outer shell opening with an area that is substantially smaller than the maximum area of a normal section of the external surface of the outer shell would be suitable. For example the outer shell may be a cube with a rectangular opening having an area substantially smaller than the area of a normal section of the outer shell.

The vessel 10 may be formed from a select blend of slip and glazes to provide a non- porous air tight material to contain the vacuum. In ceramics, slip is a diluted clay solution used for decorating or coating pottery or for casting in a mold. Slip cast ceramics have an even thickness and smooth interior. Glazing is the process of coating the piece with a thin layer of a glassy material (often a mix of dolomite, frit, silica/flint, feldspar, sodium borate, clay and whiting plus metal oxides or carbonates). This is important for functional earthenware vessels, which would otherwise be unsuitable for holding liquids due to porosity. Fig. 3 Illustrates a section of the vessel 10, showing the outer shell 11 and inner liner 14 defining a space 15. A glaze 19 is applied in the exterior surface of the outer shell. Similarly, a glaze 21 is applied to the interior surface of the inner liner 14. The glaze may be applied by dusting it over the clay, spraying, dipping, trailing or brushing on a thin slurry of glaze and water.

The vessel 10 may be formed in two sections, a top and bottom, or two haves, either of which may be affixed to each other to form a complete vessel 10 with an inner liner 14. The vessel 10 may also be assembled by first casting the inner liner 14 as a single piece and then placing the inner liner 14 within a mold to cast the outer shell 11 around the inner liner 14. Either method makes it possible for the inner liner diameter d2 to be larger than the opening 12 in the outer shell 11. This means that the inner "bole" of the pot may be any size regardless of the access opening 12 and lid of the pot. This makes for a more efficient insulation of the inner liner.

A vacuum is produced in the space 15 between the inner liner 14 and the outer shell 11 after the pot is fully fired. Preferably the vessel 10 and may have a layer of glaze or enamel. The glaze coating may be applied inside and outside of the vessel 10. Fig. 3 illustrates a cross- section through a portion of the vessel 10 showing a layer of glazing 19 applied to the outer surface of the outer shell 11, and a layer of glazing 21 applied to the inner surface of the inner liner 14. This helps to seal the vessel from any leaks.

The outer shell 11 of the vessel 10 may be provided with a small hole 23 in its bottom (see Fig. 1). This hole 23 is provided in order that a vacuum may be drawn down through the hole. After the vacuum is drawn down to the desired amount, the hole may be sealed to retain the vacuum. The seal may be facilitated by using a luer, like that used on hermetically sealed medicine vials. This is a self sealing closure, usually made of some elastomer, and pierced by a hypodermic needle. When the needle is removed the elastomer seals the hole. To ensure that the elastomer does not leak a second sealant may be applied, such as epoxy or some other type of suitable sealant type. Alternately, a closure may be inserted in hole 23 in the form of a suitable valve that can act as a "one way valve" allowing gases to escape in one direction and not in the other. Using this valve method, each teapot may have the chamber between the inner liner and the outer shell pumped down to evacuate the air providing an insulating barrier. Any suitable means of creating a partial vacuum within the chamber between the inner lining and the outer shell, such as a vacuum pump and valve, capable of retaining the created vacuum after removal of the vacuum pump. It is also conceivable that the inner liner may be cast in a first mold as a single separate piece, and then inserted within a second mold and an outer shell is then cast around it, leaving a physical gap between the inner liner and the newly cast shell. The physical gap is to be evacuated to provide the insulation zone.

The insulated vessel may be of any physical design or shape and decorated in any desired manner. The technology and method of fabrication may also be used to produce other types of vessels, such as soup tureens, serving trays, coffee pots, etc.

Fig. 4 illustrates yet another embodiment of the present invention, hi this embodiment that vessel 10 is formed from two sections, 10(a) and 10(b). It should be understood that although the the two sections illustrated in Fig. 4 are a top and bottom, the two sections amy also be sctions along a vertical axis (e.g. right side and left side). Similarly, the two sections may preferably be disposed so that the inner liner 14 is wholly formed (ie not sectioned) and the outer liner is sectioned only in the bottom. The outer shell 11 and the inner liner 14 of each section of the vessel (10(a) and 10(b)) may be molded as intergral piece as further described below. A plurality of molded vacuum form inserts 25 are disposed between the the outer shell 11 and the inner liner 14. The vacuum insert structure 25 is illustrated in Fig. 5 and may be formed of thermal insulation material 27. Many types of thermal insulation materials are well known in the art, for example polystyrene, polurethane and fiberglass. One type of insulating material 27 that may be particularly desirable is a porous material such as nanoporous silica, fiberglass or porous carbonous material (commonly known as carbon foam) or similar porous materials. The vacuum barrier structure also comprises an impermeable outer layer 29 which hermetically seals the thermal insulating material after a vacuum has been drawn. As shown in Fig 5 the vacuum barrier structure 25 may be comprised of multiple outer layers such as an outer heat resistant plastic layer 31 and a metallic coating 33. Each vacuum form insert 25 becomes somewhat stiff upon the drawing of the vacuum but remains sufficiently pliable to be insertable in the space 15.

Fig.6 illustrates a vessel 10 in the form of a teapot. The vessel 10 includes the outer shell 11 and inner liner 14. An opening 35 is provided and a spout 37 is attached at the opening. The 1 inner liner 14 should continue up the spout 37 as far as possible, providing a vacuum space between the inner liner and the outer shell. The actual distance that the vacuum space travels up the spout 37 is important as to the amount of insulation provided to the tea pot.

It is to be noted that the girth of the tea pot is larger than the neck.

To manufacture this configuration of tea pot, the mold must have special mold parts. The inner chamber of the teapot, having a larger diameter than the top cover hole, requires the use of an articulated mold piece to form the inner chamber. This makes it possible to remove the mold piece through the small top opening, once the molding process is complete. This method of molding means that the outer shell and inner chamber are cast simultaneously, in one piece.

To accomplish this process, the articulated mold piece is designed to collapse after pouring the slip, so it may be removed through a smaller diameter, that of the top opening for the tea pot cover. After the slip casting has become sufficiently firm, it may be removed from the mold, allowed to further harden and then fired in a kiln. Upon cooling, any insulation may be inserted between the two walls to provide the necessary heat retention of the finished tea pot. This would be accomplished most likely through the bottom of the pot, and then sealing the pot bottom to complete the process. This method of molding, using an articulated mold piece, is well known by one skilled in the art.

The information describing the invention herein is described by example only and is not intended to be limiting to design, application, method of fabrication, or any other limitation.

Claims

wnat is Claimed:

1. An insulated vessel comprising:

a) an outer shell having an internal surface and an outer shell opening having an area that is substantially smaller than the maximum area of a normal section of the external surface of the outer shell;

b) an inner liner disposed inside the outer shell, said inner liner having an internal surface and a liner opening having an area that is substantially smaller than the maximum area of a normal section of the external surface of the liner, said liner opening being of substantially the same shape and dimension as the outer shell opening;

c) means for insulating the space between the outer shell and inner lining.

2. The vessel of claim 1 where said means for insulating comprises means for drawing a vacuum in the space between the inner liner and the outer shell.

3. The vessel of claim 2 where said means for drawing a vacuum comprises a vacuum fitting.

4. The vessel of claim 2 wherein said means for drawing a vacuum comprises a one way valve closure.

5. The vessel of claim 1 wherein said means for insulating comprises inserting a plurality of vacuum form inserts in the space between the inner liner and outer shell.

6. The vessel of claim 5 wherein each vacuum form insert comprises

a) A supporting core; and

b) An impermeable layer encapsulating said supporting core.

7. The vessel of claim 6 wherein said supporting core is under a vacuum.

8. The vessel of claim 1 wherein said outer shell is made of ceramic material.

9. The vessel of claim 1 wherein inner liner is made of ceramic material.

10. An insulated vessel comprising:

b) an inner liner disposed inside the outer shell, said inner liner having an internal surface and a liner opening having an area that is substantially smaller than the maximum area of a normal section of the external surface of the liner, said liner opening being of substantially the same shape and dimension as the outer shell opening; and

c) a plurality of molded vacuum form insert disposed between the inner liner and the outer shell.

11. The insulated vessel of claim 10 wherein each of said vacuum form insert comprises:

a) a layer of insulating material and

b) an impermeable layer surrounding said layer of insulating material.

12. The insulated vessel of claim 11 wherein said layer of insulating material is porous.

13. The insulated vessel of claim 12 wherein said porous layer of insulating material is in a vacuum contained by said impermeable layer.

14. The insulated vessel of claim 11 wherein said impermeable layer comprises:

a) a first heat resistant polymer laminate and

b) a metal coating on said heat resistant polymer laminate.

15. A method for forming an insulated vessel comprising the steps of: a) forming an outer shell with an opening at the top, said opening having a substantially smaller area than the maximum area of a normal section of the outer shell;

b) forming an inner liner with an opening at the top, said inner liner having a maximum area of a normal section of said inner line that is substantially larger than the area of opening in inner liner

c) attaching the inner liner to the outer shell so as to form a hermetic seal; and

d) forming a means for drawing a vacuum in the space between the inner liner and outer shell.

16. The method of claim 14 wherein said steps of forming and outer shell and forming an inner liner comprise:

a) Disposing an articulated mold piece to form the inner liner and outer shell; and

b) Pouring a slip into the articulated mold piece;

c) Collapsing the articulated mold piece after the slip has become sufficiently firm;

d) Removing the articulated mold piece through the outer shell opening.

17. The method of claim 14 wherein said steps of forming an inner liner and outer shell comprise:

a) forming a first section of a vessel having an inner liner and an outer shell and an opening thereon;

b) forming a second section of a vessel having an inner liner and outer shell; and

c) joining the first and second section of the vessel.

18. The method of claim 16 further comprising of the intermediate step of inserting a plurality of vacuum form inserts in the space between the inner liner and outer shell.