CA1242980A

CA1242980A - Preserving tin

Info

Publication number: CA1242980A
Application number: CA000440141A
Authority: CA
Inventors: Johannes A. Glerum
Original assignee: Thomassen and Drijver Verblifa NV
Current assignee: Thomassen and Drijver Verblifa NV
Priority date: 1982-11-04
Filing date: 1983-11-01
Publication date: 1988-10-11
Also published as: DK484083A; DK162344B; DE3382498D1; DK484083D0; DK162344C; NL8204283A; EP0108462B1; EP0108462A1; AU583469B2; AU2044083A

Abstract

ABSTRACT

The invention relates to a preserving tin having a wall provided with a contraction extending around the circumference.
Such a wall-ironed container is known and used for packing inter alia products filled in the hot state. As a result of the subatmospheric pressure occurring in the tin after closure and cooling the known tin tends to collapse, that is to say, to exhibit indentations in the body. For this purpose said, at least one contraction is provided, which serves as a reinforcing element, However, the great disadvantage of such a contraction is that the axial resistance is drastically reduced so that the stacking height of the tins is limited.
The invention has for its object to construct a preserving tin in a manner such that there is no risk of collapsing, whilst nevertheless the axial resistance is fully maintained.
Thereto the invention proposes a preserving tin of the kind set forth in the preamble, in which the edges of the contraction are pressed substantially one against the other.

Description

X Sch/lh/48 ~2~2~

Short title: Preserving tin.
____.__________________~____ The invention relates to a preserving tin having a wall provided with a contraction extending around the circumference.
Such a wall-ironed container is known and used for packing inter alia products filled in the hot state.
As a result of the subatmospheric pressure occurring in the tin after closure and cooling the known tin tends to collapse, that is to say, to exhibit indentations in the body.
For this purpose said, at least one contraction is provided, which serves as a reinforcing element. However, the great disadvantage of such a con-traction is that the axial re-sistance is drastically reduced so that the stacking height of the tins is limited.
The invention has for its object to construct a preserving tin in a manner such that there is no risk of collapsing, whilst nevertheless -the axial resistance is fully main-tained. In -this respect the invention proposes a preserving tin of the kind set forth in the preamble, in which the edges of the contraction are pressed substantially one against the other.
In general i-t will be necessary to exert an,~."~.
' YJ~

2--axial force on the preserving tin in order to cause the edges of the contraction to approach one another. This requires an additional produc-tion step. ~ccording -to the invention, in order to avoid said addit.ional production step, the or each contraction may be dimensionecl such that after the tin is filled with a ho-t mass, the subsequent closure of khe tin and the cool.ing of the filled tin the ecl~es o:E the contraction are pressed against or substantiall.y against one another by the sl1batmospheric ~ressure caused by cooling.
Af-ter the ti.n is filled and closed the edges of the con-traction can be advantageously pressed towards one another either by a mechanical operation or under the influence of the pressure difference between the atmosphere and the interior of the tin. Since the volume of the tin is reduced, the pressure in the tin becomes accordingly higher so that a smaller wall thickness will be sufficient. In all cases the tin is stiffened axially and radially.
The invention will now be described more fully with reference to the drawing showing an arbitrary embodiment.
Fig. 1 a cylindrical preserving tin having a contraction extending around the circumference, Fig. 2 a detail II of Fig. 1, Fig. 3 the tin of FigO 1 in the state in which the edges of the con-traction are substantially pressed against one another and Fig. 4 shows a cylindrical preserving tin 1 having a cylindrical wall 3 provided with a contraction 2 extending around the circttmEerence.
Fig. 2 shows the contraction 2 on an enlarged scale. The arrows 4 indicate the distance between the edges of the contraction.
Fig. 3 shows the same tin 1. However, in the state shown in Fig. 3 the edges of the contraction 2 are pressed towards one another. To ind:Lcate the difference from Fig. 1 -the contraction is designated by reference symbol 2'. It should be noted that pressing the edges towards one another may take place in a separate production s-tep, 12~29~3~

in which an axial force is exerted on the tin either prlor to or after filllng and the closure thereof or as a result of the occurrence of subatmospheric pressure in the tin owing to filling the tin with a hot mass, the subsequent closure of the tin and the subsequent cooling of the filled tin.
Fig. 4 shows the contraction 2' on an enlarged scale. The ~istance ~' between the edges, as will be apparent ~rom a comparison between 4 and 2, is appreciably smaller than the distance designated by 4 in Fig. 2. When stacking a plurality of tins, the edges can be pressed agalnst one another so that the axlal resistancé becomes equal to that of a tin not provided with a contraction.
It is noted that the distance 4' may even be zero. For obtaining a satisfactory stackability it is, however, sufficient for the edges to be relatively near one another so thab when a stack is formed the edges are pressed against one another.
The invention is not limited to a preserving tin with only one recess of the kina described. Other numbers of recesses may be used.
Other shapes of the contraction provide the same desired result. Therefore, the invention is not limited to the shape shown in the drawing. It is furthermore possible to subject the preserving tin to an aftertreatment such that the contraction formed is pressed substantially against the inner face of the cylinder wall. In this way a substankially flat wall can be obtained, which has nevertheless all technical advantages of the invention.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A metal can having a body wall provided with an internal bead extending around the circum-ference characterized in that the edges of said bead are pressed substantially one against the other to the extent said edges contact one another under a stacking load, and said bead is proportioned so that after filling the can with a hot mass, the subse-quent closure of the can and the cooling of the filled can, the edges of said bead are pressed sub-stantially against one another by sub-atmospheric pressure caused in the can by cooling and contrac-tion.

2. A can according to claim 1, wherein said bead is initially defined by annular walls connected by an annular arcuate cross-sectional. portion, and wherein when said bead collapses with said edges of said bead moving together, said annular walls con-verge with said arcuate cross-sectional portion reducing in diameter.

3. A metal can according to claim 1, wherein said edges are in touching relation.

4. A metal can according to claim 1, wherein said bead edges are further pressed together by mechanical shortening of said body wall.

5. A method of canning a hot fill product, said method comprising the steps of providing a can including a body having at least one internally pro-jecting bead formed therein, filling the can with a hot product, closing the can while the product is hot, and permitting the product and the can to cool.
with the pressure within the can decreasing to the degree that external-internal pressure differential will cause said bead to collapse with edges of said bead moving into substantially contacting relation.

6. A method according to claim 5, wherein the can is additionally subjected to mechanical. axial pressure and said bead edges are brought into posi-tive contacting relation.