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(11) | EP 0 374 066 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A cork for thermos flask |
| (57) This invention relates to a cork for thermos flask. It comprises a number of plastic
rings , which are deformable with inner wall of the flask under heat, as compared
to ordinary cork for thermos flask , thus the sealing condition is strengthened. It
put an end to convective heat transfer between inside and outside of glass liner of
the thermos flask , as well as, it also improves the gradient of conduction of heat.
Then the object of the present invention is achieved , i. e. , the loss of heat is
reduced and the period for heat preservation is prolonged. In accordance with the
present invention the daily index of heat preservation will be increased about 10°C
relative to present international I. S. O. standard and the standard of the Ministry
of Light Industry of P.R.C. QB 8₁ - 8. The cork of this invention comprises a cork
(1), a plastic spacer (2)and a plastic bowl-like sleeve(3)( or a plastic base frame
(12), a plastic cover(13) of the base frame , a plastic handle(14), plastic spacers
(2, 2′) and a plastic bowl-like sleeve(3). |
[0001] This invention relates to a cork for thermos flask , in particular , to an efficient cork for thermos flask.
[0002] In the past , people put emphasis throughout on enhancing the quality of glass liner to improve the performance of heat preservation for the thermos flask, for example , by increasing vacuum , improving the silver-plating , or varying the prescription of the liner etc. The result is that an expensive cost has to be paid for heightening each degree of temperature. In fact , the cork is also a key factor which can effect the performance of heat preservation. As a result of the inconsistent shape and the greater dimensional error of the mouth of the glass liner , it is difficult to fit an ordinary cork with the mouth in a sealing condition , the heat is transferred by convection and greater conduction between inside and outside of the glass liner , so that , some additional losses of heat are present , therefore after 24 hours the boiling water kept by the thermos flask with an ordinary cork should not be used to make tea or coffee etc..
[0003] The object of the present invention is to improve the sealing condition between the cork and the mouth of flask thus to reduce the loss of heat and prolong the period for heat preservation.
[0004] The object is achieved by means of the following way. A number of plastic ring , which are deformable under heat , are fixed on the cork, to put an end to heat transfer by convection between inside and outside of the glass liner and improve the gradient of conduction of heat. The thermos flask manufactured according to the way of the present invention , the daily index of heat preservation will be increased about 10°C relative to present international I. S.O. standard and the standard of the Ministry of Light Industry of P.R.C.: QB 8₁-8.
[0005] This invention will be apparent now from the following detailed description of certain typical embodiments and the accompanying drawings, in which:
Fig. 1 is a sectional elevation of the plastics-corkwood composition form and structure in accordance with the present invention.
Fig. 2 is a sectional elevation of all plastics composition form and structure in accordance with the present invention.
Embodiment 1
[0006] Referring to Fig.1, the cork of present invention comprises a cork 1, whose height is between 15-50mm, a plastic spacer 2 and a plastic bowl-like sleeve 3. In cork 1 there is a funnel through hole 11 . The spacer 2 assumes a shape of wheel boss , where an end is sealed. There is a resilient ring 8 at outer circumference of said spacer and there is a chamfer β between 15°-90° at the edge of said ring. Furthermore, there is a through hole 9 at the centre of said spacer. Said plastic spacer 2 is formed by means of injection moulding on its first make. There is a bowl-like ring 6 on the plastic bowl-like sleeve 3, which bevels by an angle α between 15°-75° . The wheel boss 5 and cylinder 10 of said bowl-like sleeve 3 are formed by means of injection moulding on their first make.
[0007] The cylinder 10 on the plastic bowl-like sleeve 3 passes through said through hole 9 in said plastic spacer 2 and said funnel through hole 11 in the cork 1 and then the top of the cylinder 10 is hot-pressed and formed. Thus, said cork 1 , plastic spacer 2 and bowl-like sleeve 3 are hot riveted to an integral whole. The spaces 4 and 7 are air heat insulation layers formed by hot riveting separately.
Embodiment 2
[0009] Referring to Fig. 2, the cork of present invention comprises plastic spacers 2, 2′ , a plastic bowl-like sleeve 3 , a plastic base frame 12, a plastic cover 13 of the base frame and a plastic handle 14. There are resilient rings, 8, 8′ each on the spacer 2 , 2′ respectively. The cylinder 10 on the plastic bowl-like sleeve 3 passes through the cylindrical holes , which include holes in said plastic spacers 2, 2′ , in said base frame 12, in said plastic cover 13 and in said handle , and all of them will be hot riveted to an integral whole, the space 4 , 7 , 7′ , 15 are air heat insulation layers formed by hot riveting separately. The outer diameter of said plastic base frame 12 is φ 30-150mm, and the smaller diameter of the taper portion is φ 25-100mm.
[0010] Referring again to Fig.1 and 2 , while the upper end of said cork 1 or said plastic handle 14 is held by hand , the cork in accordance with the present invention should be inserted into the mouth of the thermos flask vertically. In this case , the bowl-like ring 6 and the resilient ring 8 (or resilient rings 8 , 8′ ) will be crushed out of shape with said mouth of flask due to heat , thereby the three or four layers of sealing ring are formed by said rings 6 and 8 together with said cork 1 or said plastic base frame 12, so that the sealing condition is strengthened, the gradient of conduction of heat is improved , then the object of the present invention is achieved, i.e, the loss of heat is reduced and the period of heat preservation is prolonged.
1. A cork for thermos flask , characterized in that it comprises cork , spacer and
bowl- like sleeve , wherein there is a cylindrical through hole at the center of the
said cork and said spacer, the cylinder on said bowl-like sleeve passes through said
cylindrical through hole ; said spacer assumes a shape of wheel boss and has a resilient
ring at its outer circumference ; there are a bowl-like ring , a wheel boss and a
cylinder on the said bowl-like sleeve; and said spacer is at least one in number.
2. A cork for thermos flask according to the claim 1 , characterized in that said
cork is made from corkwood.
3. A cork for thermos flask according to the claim 1 , characterized in that said
cork is made from plastics and is composed of base frame , cover of the base frame
and handle.
4. A cork for thermos flask according to the claim 1 , characterized in that the edge
of said resilient ring is with a chamfer β between 15° -90° .
5. A cork for thermos flask according to the claim 1 , characterized in that the bevel
angle α of said bowl-like ring is between 15° -75°.
6. A cork for thermos flask according to the claim 2, characterized in that there
is a funnel through hole at the center of said cork , and the height of it is between
15-50mm.
7. A cork for thermos flask according to the claim 1 and 2, characterized in that
the top of said cylinder is hot-pressed and formed to join said cylinder and said
cork.
8. A cork for the thermos flask according to the claim 3 , characterized in that the
outer diameter of the said plastic base frame is φ 30-150mm , the smaller diameter
of the taper portion is φ25-100mm.
9. A cork for thermos flask according to the claim 1 , 2 and 3 , characterized in
that said spacer , bowl-like sleeve, base frame and its cover are made from polyethylene
or other nonpoisonous thermoplastics by means of injection moulding.