US20260174217A1
2026-06-25
19/428,103
2025-12-20
Smart Summary: A water bottle features a hard outer layer and a soft inner bag that holds the water. Users can squeeze the soft inner bag directly through openings in the hard shell. The inner bag is made from a special type of silicone that is flexible yet durable. The outer shell is constructed from stainless steel, making it strong and long-lasting. This design allows for easy access to the water while keeping the bottle sturdy. π TL;DR
A water bottle is presented that has a stiff outer shell and a flexible inner bladder, where the flexible inner bladder fills the stiff outer shell. There are cutouts in the stiff outer shell, and through these cutouts the flexible inner bladder may be directly squeezed by a user. The inner bladder is made from Platinum-Cured Polydimethylsiloxane (PDMS) with a shore hardness between a40 and a70. The stiff outer shell may be made from stainless steel.
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A45F3/18 » CPC main
Travelling or camp articles ; Sacks or packs carried on the body; Water-bottles; Mess-tins; Cups of rigid material
A45F3/20 » CPC further
Travelling or camp articles ; Sacks or packs carried on the body; Water-bottles; Mess-tins; Cups of flexible material; Collapsible or stackable cups
B65D23/0885 » CPC further
Details of bottles or jars not otherwise provided for; Coverings or external coatings Rigid shells for receiving the bottle or part of it
B65D43/0229 » CPC further
Lids or covers for rigid or semi-rigid containers; Removable lids or covers without integral tamper element secured by rotation only on the inside, or a part turned to the inside, of the mouth of the container
B65D2543/00046 » CPC further
Lids or covers essentially for box-like containers; Details of lids or covers for rigid or semi-rigid containers; Overall construction of the lid Drinking-through lids
B65D2543/00092 » CPC further
Lids or covers essentially for box-like containers; Details of lids or covers for rigid or semi-rigid containers; Overall construction of the lid; Shape of the outer periphery curved circular
B65D2543/00518 » CPC further
Lids or covers essentially for box-like containers; Details of lids or covers for rigid or semi-rigid containers; Contact between the container and the lid on the inside or the outside of the container on the inside, or a part turned to the inside of the mouth of the container Skirt
B65D2543/00546 » CPC further
Lids or covers essentially for box-like containers; Details of lids or covers for rigid or semi-rigid containers; Contact between the container and the lid on the inside or the outside of the container on the outside, or a part turned to the outside of the mouth of the container NO contact
B65D23/08 IPC
Details of bottles or jars not otherwise provided for Coverings or external coatings
B65D43/02 IPC
Lids or covers for rigid or semi-rigid containers Removable lids or covers
The present invention generally relates to water bottles, also called hydration bottles.
Water bottles are used for many sporting activities. These can also be called hydration bottles, since they are primarily intended to be used to hydrate athletes.
Some examples of existing water bottles include squeezable bottles that are squeezed to cause fluid to exit the bottle. There are also water bottles where the bottle is rigid, which do not allow the user to cause fluid to exit the bottle through squeezing.
Other examples of water or hydration bottles use design features in the lids or nozzles to permit or close off flow of the fluids in the bottle.
Previous water bottles had various undesirable features. Some bottles were made of plastic, and so the water they dispensed had microplastics, which poses health and environmental risks. Some bottles were not easy to wash or sanitize between uses. Some bottles would not work well when used in a hockey context: they were not stiff enough to be comfortably grasped when wearing hockey gloves, which are bulky and relatively non-flexible, or if they were sufficiently stiff it was difficult to squeeze and control the flow of water from the bottle while wearing bulky hockey gloves. Such issues with hockey gloves are compounded when considering use by children and younger teenagers, who may not have the physical strength to squeeze with control while wearing relatively bulky, inflexible hockey gloves.
Considering these issues, the inventors designed a water bottle with the following characteristics:
In accord with the invention, there is provided a water bottle, comprising: a stiff outer shell of a roughly cylindrical shape with a curved surface, the curved surface having cutouts on opposite sides of the curved surface and threads on the inner part of a first end of the stiff outer shell; a flexible inner bladder of a roughly cylindrical shape, the flexible inner bladder having an opening at a first end and having an opposite second end and the flexible inner bladder being shaped so, when placed inside the stiff outer shell the first end of the flexible inner bladder reaches the threads, and the flexible inner bladder fills the inside of the stiff outer shell and fills the cutouts; the flexible inner bladder being placed inside the stiff outer shell and the flexible inner bladder and the inner part of the first end of the stiff outer shell being configured so when a lid is screwed onto the threads, the first end of the flexible inner bladder forms a gasket; where the flexible inner bladder is made from Platinum-Cured Polydimethylsiloxane (PDMS) with a shore hardness between a40 and a70; and the flexible inner bladder is removable from the stiff outer shell.
In an aspect of the invention, the water bottle of claim 1 further comprising the lid being screwed onto the threads. In another aspect of the invention, the second end of the flexible inner bladder is shaped to form a stable base to support the water bottle. In still another aspect of the invention, the flexible inner bladder is shaped so that the inner bladder when filling the cutouts extends slightly outside the stiff outer shell. In another aspect of the invention, the first end of the flexible inner bladder has a lip, and the inner surface of the first end of the stiff outer shell has a shelf, and further comprising a lid, where the lip and shelf and lid are configured so, when the lid is screwed onto the threads, the lip and shelf form a gasket. In another aspect of the invention, the distance from the second end of the flexible inner bladder to the first end of the stiff outer shell is around 210 mm+/β10%; the second end of the stiff outer shell is 66 mm+/β10% in diameter; the first end of the stiff outer shell is 80 mm+/β10% in diameter; the second end of the flexible inner bladder extends approximately 5 mm+/β10% below the second end of the stiff outer shell in the axial direction of the stiff outer shell; the cutouts are located between 24 mm +/β10% from the first end of the stiff outer shell and 25 mm+/β10% from the second end of the stiff outer shell; and the cutouts are 156 mm+/β10% long in the axial direction of the stiff outer shell.
In accord with the invention, there is provided a kit for assembling a water bottle, comprising: a stiff outer shell of a roughly cylindrical shape with a curved surface, the curved surface having cutouts on opposite sides of the curved surface and threads on the inner part of a first end of the stiff outer shell; and a flexible inner bladder of a roughly cylindrical shape, the flexible inner bladder having an opening at a first end and having an opposite second end and the flexible inner bladder being shaped so, when placed inside the stiff outer shell the first end of the flexible inner bladder reaches the threads, and the flexible inner bladder fills the inside of the stiff outer shell and fills the cutouts; where the flexible inner bladder and the inner part of the first end of the stiff outer shell being configured so when a lid is screwed onto the threads, the first end of the flexible inner bladder forms a gasket; and where the flexible inner bladder is made from Platinum-Cured Polydimethylsiloxane (PDMS) with a shore hardness between a40 and a70.
In an aspect of the invention, the second end of the flexible inner bladder is shaped to form a stable base to support the water bottle when assembled. In another aspect of the invention, the flexible inner bladder is shaped so that the flexible inner bladder when filling the cutouts extends slightly outside the stiff outer shell. In still another aspect of the invention, the first end of the flexible inner bladder has a lip, and the inner surface of the first end of the stiff outer shell has a shelf, and further comprising a lid, where the lip and shelf and lid are configured so, when the lid is screwed onto the threads, the lip and shelf form a gasket.
In accord with the invention, there is provided a method of assembling a water bottle, comprising placing a flexible inner bladder inside a stiff outer shell, where the stiff outer shell is of a roughly cylindrical shape with a curved surface, the curved surface having cutouts on opposite sides of the curved surface and threads on the inner part of a first end of the stiff outer shell; the flexible inner bladder is of a roughly cylindrical shape, the flexible inner bladder having an opening at a first end and having an opposite second end and the flexible inner bladder being shaped so, when placed inside the stiff outer shell the first end of the flexible inner bladder reaches the threads, and the flexible inner bladder fills the inside of the stiff outer shell and fills the cutouts; the flexible inner bladder and the inner part of the first end of the stiff outer shell being configured so when a lid is screwed onto the threads, the first end of the flexible inner bladder forms a gasket; where the flexible inner bladder is made from Platinum-Cured Polydimethylsiloxane (PDMS) with a shore hardness between a40 and a70; and the flexible inner bladder is removable from the stiff outer shell. In an aspect of the invention, the lid is screwed onto the threads.
In accord with the invention, there is provided a method of using a water bottle, where the water bottle comprises: a stiff outer shell of a roughly cylindrical shape with a curved surface, the curved surface having cutouts on opposite sides of the curved surface and threads on the inner part of a first end of the stiff outer shell; a flexible inner bladder of a roughly cylindrical shape, the flexible inner bladder having an opening at a first end and having an opposite second end and the flexible inner bladder being shaped so, when placed inside the stiff outer shell the first end of the flexible inner bladder reaches the threads, and the flexible inner bladder fills the inside of the stiff outer shell and fills the cutouts; the flexible inner bladder being placed inside the stiff outer shell, and the flexible inner bladder and the inner part of the first end of the stiff outer shell being configured so when a lid is screwed onto the threads, the first end of the flexible inner bladder forms a gasket, and the lid being screwed onto the threads; where the flexible inner bladder is made from Platinum-Cured Polydimethylsiloxane (PDMS) with a shore hardness between a40 and a70; and the flexible inner bladder being removable from the stiff outer shell; comprising directly squeezing the flexible inner bladder by squeezing the part of the flexible inner bladder that fills the cutouts.
Embodiments herein will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the scope of the claims, wherein like designations denote like elements, and in which:
FIG. 1 is a perspective view of a stiff outer shell;
FIG. 2 is a perspective view of a flexible inner bladder;
FIG. 3 is a perspective view of the water bottle including the stiff outer shell and the flexible inner bladder;
FIG. 4 is a bottom perspective view of the water bottle including the stiff outer shell and the flexible inner bladder;
FIG. 5 is a bottom view of the water bottle showing section 6-6;
FIG. 6 is a cutaway view of the water bottle from the side along section 6-6;
FIG. 7 is a detailed view of the flexible inner bladder and the stiff outer shell at the top of the water bottle;
FIG. 8 is a top view of the water bottle with a lid showing section 9-9;
FIG. 9 is a cutaway view of the water bottle with a lid from the side along section 9-9; and
FIG. 10 is a detailed view of the flexible inner bladder and the stiff outer shell at the top of the water bottle with a lid, forming a gasket.
The inventive water bottle includes two parts: a stiff outer shell, and a flexible inner bladder. When in use, a third part, a lid, is added, which allows access to the water in the flexible inner bladder and also interacts with the top of the flexible inner bladder and a shelf on the inner top part of the stiff outer shell to form a gasket.
FIG. 1 is a perspective view of a stiff outer shell. Turning to FIG. 1, there is a stiff outer shell 10. The stiff outer shell is of a roughly cylindrical shape, with a first end 12, a second end 14, and a curved surface 16. Roughly cylindrical means that while the stiff outer shell can be a perfect cylinder, stiff outer shells with small deviations from a perfect cylinder may also be used. The first end 12 of the stiff outer shell and the second end 14 of the stiff outer shell are open. The inner surface of the first end 12 has threads 18 and a shelf 20. Shelf 20 includes a notch 17. On opposite sides of the curved surface 16 are cutouts 22 and 24.
FIG. 2 is a perspective view of the flexible inner bladder. Turning to FIG. 2, there is a flexible inner bladder 30. The flexible inner bladder is of a roughly cylindrical shape, with a first end 32 and a second end 34 and a curved surface 35. Roughly cylindrical means that while the flexible inner bladder can be a perfect cylinder, flexible inner bladders with small deviations from a perfect cylinder may also be used. The first end 32 of the flexible inner bladder is open, and the second end 34 of the flexible inner bladder is closed and flat. The external surface of the first end 32 has a lip 36. Lip 36 includes a key 37. On opposite sides of the curved surface 35 are raised portions 38 and 39.
FIG. 3 is a perspective view of the water bottle including the stiff outer shell and the flexible inner bladder. Turning to FIG. 3, the flexible inner bladder 30 is now placed inside stiff outer shell 10. Flexible inner bladder 30 is shaped so as to fill stiff outer shell 10, and raised portions 38 and 39 are shaped so as to fill cutouts 22 and 24. In a preferred embodiment, the flexible inner bladder 30 is shaped so that raised portions 38 and 39 protrude past the curved surface 16 when the bottle is assembled. In a preferred embodiment, the flexible inner bladder 30 is shaped so that raised portions 38 and 39 protrude past the curved surface 16 when the bottle is assembled, by a distance of around 1.5 mm for the raised edge 38a around raised portions 38 and 39 and around 0.8 mm in the main surface 38b of the raised portions 38 and 39. In this paragraph, around means that the measurements given are +/β10%.
Although not pictured in FIG. 3, when assembled, the key 37 (of lip 36 of the flexible inner bladder) fits into notch 17 (of shelf 20 of the stiff outer shell 10).
FIG. 4 is a bottom perspective view of the water bottle including the stiff outer shell and the flexible inner bladder. Turning to FIG. 4, the flexible inner bladder 30 is placed inside stiff outer shell 10. Flexible inner bladder 30 is shaped so as to fill stiff outer shell 10, and raised portions 38 and 39 are shaped so as to fill cutouts 22 and 24. In a preferred embodiment, the flexible inner bladder 30 is shaped so that raised portions 38 and 39 protrude past the curved surface 16 when the bottle is assembled. In a preferred embodiment, the flexible inner bladder 30 is shaped so that raised portions 38 and 39 protrude past the curved surface 16 when the bottle is assembled, by a distance of around 1.5 mm for the raised edge 38a around raised portions 38 and 39 and around 0.8 mm in the main surface 38b of the raised portions 38 and 39. In this paragraph, around means that the measurements given are +/β10%.
The second end of flexible inner bladder 30 is a flat surface 40. In a preferred embodiment, flat surface 40 of flexible inner bladder 30 is shaped and configured so that the assembled water bottle will be stable when placed down upon flat surface 40.
FIG. 5 is a bottom view of the water bottle showing section 6-6.
FIG. 6 is a cutaway view of the water bottle from the side along section 6-6. Turning to FIG. 6, there is stiff outer shell 10 and flexible inner bladder 30. Flexible inner bladder 30 has bottom 40 and raised portions 38 and 39.
The first end of stiff outer shell 10 has a shelf 20, and the first end of flexible inner bladder 30 has a lip 36, and lip 36 and shelf 20 are shaped to interlock as shown in FIG. 6. This is seen in greater detail in FIG. 7, which is indicated by circle 7 in FIG. 6.
FIG. 7 is a detailed view of the flexible inner bladder and the stiff exterior at the top of the water bottle. Turning to FIG. 7, the first end of stiff outer shell 10 has a shelf 20, and the first end of flexible inner bladder 30 has a lip 36, and lip 36 and shelf 20 are shaped to interlock as shown in FIG. 7.
FIG. 8 is a top view of the water bottle with a lid showing section 9-9. Turning to FIG. 8, there is a lid 50 which has been attached by screwing into threads 18.
FIG. 9 is a cutaway view of the water bottle with a lid from the side along section 9-9. Turning to FIG. 9, there is stiff outer shell 10 and flexible inner bladder 30. Flexible inner bladder 30 has bottom 40 and raised portions 38 and 39. The first end of stiff outer shell 10 has a shelf 20, and the first end of flexible inner bladder 30 has a lip 36, and lip 36 and shelf 20 are shaped to interlock as shown in FIG. 9 and to form a gasket when lid 50 is screwed onto threads 18. This is seen in greater detail in FIG. 10, which is indicated by circle 10 in FIG. 9.
FIG. 10 is a detailed view of the flexible inner bladder and the stiff exterior at the top of the water bottle with a lid, forming a gasket. Turning to FIG. 10, the first end of stiff outer shell 10 has a shelf 20, and the first end of flexible inner bladder 30 has a lip 36, and lip 36 and shelf 20 are shaped to interlock as shown in FIG. 10. When lid 50 is screwed onto threads 18, a lower portion 52 of lid 50 presses into lip 36, forming a gasket.
One advantage of this approach is that the flexible inner bladder 30 can be removed from outer shell 10, and washed and cleaned, and then flexible inner bladder 30 can be placed back within outer shell 10 to re-assemble the water bottle. When re-assembling the water bottle, the key 37 (of lip 36 of the flexible inner bladder) fits into notch 17 (of shelf 20 of the stiff outer shell 10).
Stiff outer shell 10 is stiff in that it needs to provide structure to the water bottle when assembled and allow the water bottle to be grasped in a clumsy manner when grasped by someone, including children and young teenagers, wearing relatively bulky, inflexible hockey gloves. The stiffness should also aid in the bottle standing upright when placed down on bottom 40, and should allow the creation of a gasket when lid 50 is screwed into threads 18. In a preferred embodiment, the stiff outer shell 10 is made from stainless steel.
In a preferred embodiment, the stiff outer shell is made from stainless steel with a Young's modulus of 195 GPa, Poisson's ratio of 0.3, density of 8000 kg/m{circumflex over (β)}3, a bending stiffness measure (squeezing the stiff outer shell from the sides) of around 233 KN/m, and a torsion stiffness measure (twisting via a cap) of around 705 Nm/rad.
In use, the flexible inner bladder 30 of the assembled water bottle has water or some other liquid placed inside. To access the water or other liquid, the lid 50 is opened (for clarity, while not unscrewing lid 50 from threads 18) and flexible inner bladder 30 is squeezed by directly squeezing raised portions 38 and 39. When the user has finished dispensing the water or other liquid, the user stops squeezing raised portions 38 and 39, and the flexible inner bladder expands back to its default shape as illustrated in FIGS. 2-10, where raised portions 38 and 39 fill cutouts 22 and 24.
A wide variety of lids 50 may be used with the water bottle, as long as the lid is shaped and configured to form a gasket when screwed onto threads 18 as described above. The lid 50 also must have a way to be opened without unscrewing the lid 50 from threads 18, to allow the user to access the water or liquid in flexible inner bladder 30.
In a preferred embodiment, the water bottle also includes a carrying strap or mechanism. This can allow the water bottle to be more easily and conveniently carried (such as through a shoulder strap), or to be attached to a bag (such as a hockey bag or sport bag or backpack). This is particularly important for athletes, many of whom have their hands full carrying their sports equipment and bag; for example, a hockey player carries into the rink a large bag of equipment and a stick, in addition to their water bottle.
The choice of material for flexible inner bladder 30 is critical, as the material should not release microplastics into the water in the bladder, should be flexible enough to allow the flexible inner bladder to be squeezed and force liquid out of the flexible inner bladder, should be elastic enough to return to its original shape when the user has finished squeezing the flexible inner bladder, must be durable enough to not deteriorate through continuous washing and use, must be capable of forming a gasket as discussed above, should have these properties in a wide range of temperatures, and in particular cold temperatures as encountered in a hockey or skating rink. After testing and experimentation, the preferred material for the flexible inner bladder is Platinum-Cured Polydimethylsiloxane (PDMS). After testing and experimentation, the preferred shore hardness is between a40 and a70. In another preferred embodiment, the preferred shore hardness is between a30 and a80. Platinum-Cured Polydimethylsiloxane with a shore hardness between a40 and a70 has the following properties:
| Property | Specification |
| Temperature | β60Β° C. to 200Β° C. (β76Β° F. to 392Β° F.). Some |
| Range | formulations can withstand up to 250Β° C. (482Β° F.). |
| Hardness | Typically 20 to 80 Shore A (a20 to a80). |
| Tensile Strength | 6-10 MPa, ensuring durability under repeated flexing |
| and squeezing. | |
| Elongation at | 200-700%, providing excellent elasticity for robust |
| Break | use. |
| Compression Set | <10% after 24 hours at 150Β° C. (302Β° F.), ensuring |
| long-term shape retention. | |
| Tear Resistance | 15-40 kN/m, ideal for applications prone to frequent |
| wear. | |
| Chemical | Resistant to water, alcohol, weak acids, and some oils. |
| Resistance | Avoid prolonged exposure to strong acids, bases, |
| or solvents. | |
The choice of materials and the design of the water bottle have been chosen with end of life and recycling and reuse in mind. The flexible inner bladder can be removed from the stiff outer shell and replaced with a new flexible inner bladder without the need to purchase a new stiff outer shell. This is further reinforced by avoiding bonding between the stiff outer shell and the flexible inner bladder. In addition, the flexible inner bladder is manufactured as one piece (in a single part mold) and the use of glue is avoided, as the glue could lead to more rapid deterioration of the flexible inner bladder and/or could result in particles being released into the fluid in the bottle to the detriment of the user. The choice of Platinum-Cured Polydimethylsiloxane (PDMS) as the material of the flexible inner bladder is also chosen with recyclability and compressibility in mind.
In a preferred embodiment, the water bottle is designed to hold 750 ml of water or another liquid, and is designed to fit in a cup holder or knapsack slot. Its dimensions are:
In another preferred embodiment, the water bottle is designed to hold 750 ml of water or another liquid, and is designed to fit in a cup holder or knapsack slot. Its dimensions are approximately:
In another preferred embodiment, the water bottle is designed to hold 500 ml of water or another liquid.
1. A water bottle, comprising:
a stiff outer shell of a roughly cylindrical shape with a curved surface, the curved surface having cutouts on opposite sides of the curved surface and threads on the inner part of a first end of the stiff outer shell;
a flexible inner bladder of a roughly cylindrical shape, the flexible inner bladder having an opening at a first end and having an opposite second end and the flexible inner bladder being shaped so, when placed inside the stiff outer shell the first end of the flexible inner bladder reaches the threads, and the flexible inner bladder fills the inside of the stiff outer shell and fills the cutouts;
the flexible inner bladder being placed inside the stiff outer shell and the flexible inner bladder and the inner part of the first end of the stiff outer shell being configured so when a lid is screwed onto the threads, the first end of the flexible inner bladder forms a gasket;
where the flexible inner bladder is made from Platinum-Cured Polydimethylsiloxane (PDMS) with a shore hardness between a40 and a70; and
the flexible inner bladder is removable from the stiff outer shell.
2. The water bottle of claim 1 further comprising the lid being screwed onto the threads.
3. The water bottle of claim 1, where the second end of the flexible inner bladder is shaped to form a stable base to support the water bottle.
4. The water bottle of claim 3, where the flexible inner bladder is shaped so that the inner bladder when filling the cutouts extends slightly outside the stiff outer shell.
5. The water bottle of claim 3, where the first end of the flexible inner bladder has a lip, and the inner surface of the first end of the stiff outer shell has a shelf, and further comprising a lid, where the lip and shelf and lid are configured so, when the lid is screwed onto the threads, the lip and shelf form a gasket.
6. The water bottle of claim 5, further comprising:
the distance from the second end of the flexible inner bladder to the first end of the stiff outer shell is around 210 mm+/β10%;
the second end of the stiff outer shell is 66 mm+/β10% in diameter;
the first end of the stiff outer shell is 80 mm+/β10% in diameter;
the second end of the flexible inner bladder extends approximately 5 mm+/β10% below the second end of the stiff outer shell in the axial direction of the stiff outer shell;
the cutouts are located between 24 mm+/β10% from the first end of the stiff outer shell and 25 mm+/β10% from the second end of the stiff outer shell;
and
the cutouts are 156 mm+/β10% long in the axial direction of the stiff outer shell.
7. A kit for assembling a water bottle, comprising:
a stiff outer shell of a roughly cylindrical shape with a curved surface, the curved surface having cutouts on opposite sides of the curved surface and threads on the inner part of a first end of the stiff outer shell;
and
a flexible inner bladder of a roughly cylindrical shape, the flexible inner bladder having an opening at a first end and having an opposite second end and the flexible inner bladder being shaped so, when placed inside the stiff outer shell the first end of the flexible inner bladder reaches the threads, and the flexible inner bladder fills the inside of the stiff outer shell and fills the cutouts;
where the flexible inner bladder and the inner part of the first end of the stiff outer shell being configured so when a lid is screwed onto the threads, the first end of the flexible inner bladder forms a gasket; and where the flexible inner bladder is made from Platinum-Cured Polydimethylsiloxane (PDMS) with a shore hardness between a40 and a70.
8. The kit of claim 7, where the second end of the flexible inner bladder is shaped to form a stable base to support the water bottle when assembled.
9. The kit of claim 8, where the flexible inner bladder is shaped so that the flexible inner bladder when filling the cutouts extends slightly outside the stiff outer shell.
10. The kit of claim 8, where the first end of the flexible inner bladder has a lip, and the inner surface of the first end of the stiff outer shell has a shelf, and further comprising a lid, where the lip and shelf and lid are configured so, when the lid is screwed onto the threads, the lip and shelf form a gasket.
11. A method of assembling a water bottle, comprising placing a flexible inner bladder inside a stiff outer shell,
where the stiff outer shell is of a roughly cylindrical shape with a curved surface, the curved surface having cutouts on opposite sides of the curved surface and threads on the inner part of a first end of the stiff outer shell;
the flexible inner bladder is of a roughly cylindrical shape, the flexible inner bladder having an opening at a first end and having an opposite second end and the flexible inner bladder being shaped so, when placed inside the stiff outer shell the first end of the flexible inner bladder reaches the threads, and the flexible inner bladder fills the inside of the stiff outer shell and fills the cutouts;
the flexible inner bladder and the inner part of the first end of the stiff outer shell being configured so when a lid is screwed onto the threads, the first end of the flexible inner bladder forms a gasket;
where the flexible inner bladder is made from Platinum-Cured Polydimethylsiloxane (PDMS) with a shore hardness between a40 and a70; and
the flexible inner bladder is removable from the stiff outer shell.
12. The method of claim 11, further comprising the lid being screwed onto the threads.
13. (canceled)