EP0374066B1

EP0374066B1 - A cork for thermos flask

Info

Publication number: EP0374066B1
Application number: EP19890440130
Authority: EP
Inventors: Li-Fang Wang; Shu-Xing Deng
Original assignee: SHENZHEN LIU HUA HOSPITAL
Current assignee: SHENZHEN LIU HUA HOSPITAL
Priority date: 1988-12-10
Filing date: 1989-12-08
Publication date: 1993-03-31
Anticipated expiration: 2009-12-08
Also published as: DE68905780D1; RU1774859C; JPH02271815A; CN1043254A; EP0374066A1

Description

This invention relates to a cork for thermos flask, in particular, to an efficient cork for thermos flask.
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 termos flask with an ordinary cork should not be used to make tea or coffee etc..
It is known from GB-A-784 917 a cork for thermos flask, comprising a cork body, at least one spacer and a sleeve, each spacer having a resilient ring at its outer circumference and wherein there is a cylindrical through hole at the center of said cork body and said spacer.
The object of the present invention is to provide a new structure of the cork and improve the sealing condition between the cork body and the mouth of the flask thus to reduce the loss of heat and prolong the period for heat preservation.
The object is achieved by means of the following way. A number of plastic rings, which are deformable under heat, are fixed on the cork body, 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 8,-8.
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

Referring to Fig. 1, the cork of present invention comprises a cork body 1, whose height is between 15-50 mm, a plastic spacer 2 and a plastic truncated sleeve 3. In the cork body 1 there is a funnel-shaped 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 center of said spacer. Said plastic spacer 2 is formed by means of injection moulding on its first make. There is a tapered ring 6 on the plastic truncated sleeve 3, which bevels by an angle α between 15° -75°. The wheel boss 5 and cylinder 10 of said truncated sleeve 3 are formed by means of injection moulding on their first make.
The cylinder 10 on the plastic truncated sleeve 3 passes through said through hole 9 in said plastic spacer 2 and said funnel-shaped through hole 11 in the cork body 1 and then the top of the cylinder 10 is hot-pressed and formed. Thus, said cork body 1, plastic spacer 2 and truncated 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

This embodiment has substantially the same elements and structure with embodiment 1.
Referring to Fig. 2, the cork of present invention comprises plastic spacers 2, 2′, a plastic truncated 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 truncated 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 spaces 4, 7, 7′, 15 are air heat insulation layers formed by hot riveting separately. The outer diameter of said plastic base frame 12 is ⌀ 30-150 mm, and the smaller diameter of the taper portion is ⌀ 25-100 mm.
Referring again to Fig. 1 and 2, while the upper end of said cork body 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 tapered 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 body 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 for heat preservation is prolonged.
In accordance with present invention, said plastic spacer 2, 2′, plastic truncated sleeve 3, plastic base frame 12 and plastic cover 13 of the base frame are made all the same by polyethylene or other nonpoisonous thermoplastics by means of injection moulding.
This invention has the effect that the loss of heat is reduced and the period for heat preservation is prolonged.

Claims

A cork for thermos flask, comprising a cork body (1), at least one spacer (2, 2′) and a truncated sleeve (3), each spacer (2, 2′) having a resilient ring (8, 8′) at its outer circumference and wherein there is a cylindrical through hole (9) at the center of said cork body (1) and said spacer (2, 2′), characterized in that said truncated sleeve (3) comprises a tapered ring (6), a wheel boss (5) and a cylinder (10), which passes through said cylindrical through hole (9), and said spacer (2, 2′) assumes a shape of wheel boss.
A cork for thermos flask according to claim 1, characterized in that the cork body (1) is made from corkwood.
A cork for thermos flask according to claim 1, characterized in that the cork body (1) is made from plastics and is composed of base frame (12), cover (13) of the base frame (12) and handle (14).
A cork for thermos flask according to claim 1, characterized in that the edge of said resilient ring (8, 8′) is with a chamfer β between 15° -90°.
A cork for thermos flask according to claim 1, characterized in that the bevel angle α of said tapered ring (6) is between 15° -75°.
A cork for thermos flask according to claim 2, characterized in that there is a funnel-shaped through hole (11) at the center of said cork body (1) and the height of it is between 15-50 mm.
A cork for thermos flask according to claims 1 and 2, characterized in that the top of said cylinder (10) is hot-pressed and formed to join said cylinder (10) and said cork body (1).
A cork for thermos flask according to claim 3, characterized in that the outer diameter of the said plastic base frame (12) is ⌀ 30 - 150 mm, the smaller diameter of the taper portion is ⌀ 25-100 mm.
A cork for thermos flask according to claims 1 and 3, characterized in that said spacer (2, 2′), truncated sleeve (3), base frame (12) and its cover (13) are made from polyethylene or other non-poisonous thermoplastics by means of injection moulding.