CN1777546A - Drums including foil seals - Google Patents

Abstract

The invention relates to a tank comprising a membrane seal (5) having a continuous flange (3) in a tank shell (1), said flange facing inwards in the vicinity of a tank rim (8), preferably at a distance of between 1mm and 10mm from said rim. The flange is connected in a sealing manner to a sealing film (5), for example a foil film, in particular a tear-open foil. When the tank is viewed vertically, the upper part (3a) of the flange facing the edge of the tank and the lower part (3b) of the flange facing the interior of the tank extend horizontally or obliquely inwards in a uniform or staggered manner. The flange (3) may have a substantially semi-circular or triangular cross-section and preferably has an inclined lower portion (3b) to allow for complete emptying of the tank. In one embodiment, the lid (7) engages the flange (3) in a direct fit through the rim thickness (6).

Description

Drums including foil seals

technical field

The present invention relates to a can comprising a membrane seal, wherein the sealing membrane is sealed on a bead which is completely continuous in the top area of the tank shell, thereby creating the possibility of excessive pressure inside the can The case effectively counteracts the peel force generated on the contact surface of the film and the can shell.

Background technique

Some cans are resealable with closures after opening, while other cans, especially discarded cans, become empty after they are opened and are disposed of as waste depending on the material from which they are made. Drums are usually made of cardboard, plastic or sheet metal material.

Membrane foils, usually made of paper or made of aluminium, are often used as sealing material for cans. There are many known solutions for this purpose, only a few of which are listed here. Typically, a membrane foil in the form of a disc, which seals the can opening and has a raised ring, is sealed to the inner wall of the can by the ring in the region of the can opening. Thus, for example, EP 0 700 838 discloses a can with a conical can shell which flares upwards slightly in the top region and on which a sealing membrane seals on the inside. The object of EP 0 700 838 is firstly to replace the traditional sheet metal lid by a membrane, and secondly to avoid sealing the membrane completely vertically on the inner wall of the tank and avoiding the use of U-shaped There are technical difficulties associated with prefabricated membranes.

When pressure is exerted on the membrane from the inside, for example during tank filling or during air transport, a peel force acts at the connection of the membrane foil to the flange. Therefore, the connection must be relatively strong to be able to counteract the peeling force, which in turn makes it more difficult to tear off the foil.

Although currently in the case of tab-tab sheet metal lids a flange in the can shell is commonly used to prevent injury, the prior art only discloses some cans with flanges for other purposes, however, this Different from the present invention by having other objects and other measures. Thus, for example FR 917 018 tries to ensure a fixed position of the membranous disc and thus uses a flange as a stop for the membranous ring during sealing. GB 532 834 attempts to seal the tank barrel by a membrane disc. The inwardly curled can rim keeps the disc rim on the horizontal flange portion.

Another can with a flange and with a membrane seal is described in document CH-A5-643.502. In the case of this known solution, the opening of the can is covered by a membrane that is sealed on a continuous flange formed by flattening the material of the can shell. Such a flange has a number of disadvantages and is therefore not practically used at all in practice: the flange is difficult to manufacture, which in practice can only be made in a number of operations; it weakens the can shell material due to sharp bends; it Residue-free emptying of the can is hindered; it yields in an elastic manner when the membrane is sealed thereon. In one embodiment an additional flange is provided for ensuring that the can lid remains securely in the can body in the closed position of said can lid, which embodiment is even more complex to produce and require more material. The additional material required may seem insignificant in the case of individual cans, but in the case of mass production for such cans the material required is quite significant. With fierce competition in the field, every extra requirement, even a little bit, is a drawback that should be avoided as much as possible.

Contents of the invention

The object of the present invention is therefore to eliminate said disadvantages of the known prior art in the case of cans with membrane seals. According to the invention, the above object is achieved by in particular providing a can having an inwardly directed flange in the top region, directly below the rim of the can, preferably at a distance of 1 mm to no more than 10 mm below the rim of the can , the flange extends along the entire perimeter of the can and the sealing membrane is sealed on top of the flange.

In this context, the term "top" should be understood as the side of the flange facing the rim of the can. The "bottom" of the flange is to be understood as the side of the flange facing the interior of the can.

Further developments and advantageous developments of the invention are described in the characterizing clauses of the dependent claims.

The flange according to the invention has a sufficient axial extension and can optionally be produced by crimping (in a manner known per se) in a single operation. Furthermore, the flange has little elasticity when a sealing film (eg a membrane foil) is sealed thereon. This makes the connection of the membrane foil sealing the can to the can shell more stable and, nevertheless, does not make tearing the membrane more difficult. Thanks to the formation of the flange according to the invention, as shown in Figures 1, 2 and 3b, the can can be emptied virtually without leaving residues and with minimal weakening of the can shell. Due to the configuration of the flange directly below or immediately below the rim of the can, maximum use can be made of the interior volume of the can.

The invention relates to a tank comprising: a membrane seal having a flange in the tank shell, in the region of the tank opening, preferably at a distance of 1 mm to 10 mm from the tank edge, The flange extends around the entire circumference of the tank and is sealed by a sealing film (for example, a film foil), especially a tearable foil, the top of the flange faces the tank opening or faces the edge of the tank, the edge of the flange The bottom faces the inside of the tank, and considering that the tank is vertical, the flanges extend inward uniformly or staggered horizontally or obliquely. In principle, any combination of horizontal and/or inclined flange tops and bottoms is within the scope of the invention. Preferably, however, at least a portion of the bottom of the flange is sloped to facilitate emptying of the tank. A tight seal between the closing membrane and the can flange can be obtained by suitable measures such as adhesive bonding or heat sealing.

The invention makes it possible to bond a membrane foil (which preferably consists of paper or aluminium) to the flange also by means of an adhesive applied on the sloping or horizontal top of said flange (after its initial or cooling, followed by heating). Partial sealing, or said membrane foil sealing by means of a heat-sealing layer applied to the membrane. However, this also ensures better retention of the membrane foil, preventing accidental removal (peeling) of the foil from the inner flange, since only a part of the upwardly directed internal force acts in a direction which lifts the bonding surface.

Description of drawings

Further features, advantages and details of the invention will be explained in more detail with reference to the accompanying drawings. In the attached picture:

Figure 1 shows a first embodiment comprising the fastening of the membrane foil to the semicircular flange and the vertical part of the inner wall of the tank by means of an annular portion of the membrane foil;

Figure 2 shows a second embodiment comprising the fastening of a membrane foil without an annular portion to a triangular flange arranged just below the edge of the upper can; and

Figures 3a and 3b show further embodiments of flanges according to the invention.

Detailed ways

As shown in FIG. 1 , the can shell 1 has a bead 4 at the upper can edge 8 . Slightly below the upper can rim 8 , ie preferably at a distance of 1 to 10 mm from the can rim, an inwardly facing semicircular flange 3 is formed. On the side 3 a of the flange 3 facing the upper can rim 8 , a membrane foil 5 is sealed at reference numeral 2 in a manner known per se, which may have a tear-off, not shown, known per se. Pull ring (tab). According to the invention, however, the membrane foil at least partially seals the top of the flange, preferably at the top of the flange and an adjacent, linear portion of the inner wall of the can.

According to a second embodiment as shown in Figure 2, the can body 1 is provided with a triangular flange 3, however, its border or transition with the can shell is preferably rounded. The membrane foil 5 is sealed at 2 to the flange 3 at a portion 3 a pointing towards the upper can edge 8 . Because this part is inclined, the internal force acting on the membrane foil 5 due to the can pressure is only partly as a peeling force. Thus, the metal foil 5 is able to provide a relatively great resistance to accidental and undesired detachment. In addition, the can shell 1 can be closed by a lid 7 held in an interlocking manner on the upper part by its snapping onto the can rim 8 and its at least partial engagement with the flange 3 , preferably with the rim flange 6 On the edge 8 of the tank barrel.

In the case of the flange according to the embodiment of Figures 3a and 3b, the peeling force acting on the sealing film due to the internal pressure of the can is even smaller than in the case of the flange shape according to Figures 1 and 2, so that Resistance to diaphragm peeling is even greater.

Furthermore, the flange 3 of the embodiment according to Fig. 3b has an inclined bottom 3b, so that the can contents can be completely emptied without residue. The curvature of the flange between the horizontal linear top 3a (in case the tank is vertical) and the sloping bottom 3b may be angled or rounded. For a sloping bottom 3b, either linear or curved, the angle (in the case of a vertical tank) with respect to the horizontal linear portion 3a of the flange 3 does not matter, and in any case the bottom 3b is aligned with the Any deviation in the horizontal path facilitates complete emptying of the tank. A flange according to the invention may have, for example, an inner (axial) height of 50%, optionally approximately 100 to 150%, of its radial depth. However, the flange can also have a smaller inner height, especially in the case of the horizontal top 3a of the flange 3 according to Figures 3 and 3b (with the can vertical).

According to the invention, it is also ensured that the resistance to peeling forces offered by the joint is increased without having to exert a greater force for tearing the joint. Thus, an optimization of the solution to two partially conflicting technical requirements is provided.

According to the invention, it is not necessary to form and use the second flange which is otherwise required in the case of this type of can. As a result, the quantitative change of reducing the number of flanges becomes a qualitative change: using a single flange for two different purposes.

It will be appreciated that the measures according to the invention not only provide a simple and economical solution, but also help to eliminate tolerance problems without the use of complex tools.

Claims (7)

1. A tank comprising a tank shell (1), a tank rim (8) and a membrane seal (5), characterized in that the tank is in the vicinity of the tank rim, preferably at a distance from the tank rim At a distance of 1 mm to 10 mm from the edge there is a continuous, inwardly facing flange (3) in the tank shell which is connected by a seal to a sealing film (5), for example a membrane foil, in particular a tear-off On the open foil, the top (3a) towards the rim of the tank and the bottom (3b) of the flange towards the inside of the tank extend inwards inwards uniformly or staggered horizontally or obliquely when the tank is vertical. 2. The canister of claim 1, wherein the flange has a generally semicircular or triangular cross-section. 3. A can according to claim 1, wherein the flange has a horizontal top and a sloped or curved bottom when the can is upright. 4. A can according to any one of claims 1 to 3, wherein the slope is approximately 45°. 5. Can according to any one of claims 1 to 4, characterized in that the sealing membrane is additionally connected by a seal to the part of the can shell adjacent to the top of the flange (1a )superior. 6. A can according to any one of claims 1 to 5, characterized in that the sealing membrane is connected to the flange and is optionally adhesively bonded or heat-sealed with a seal And it is connected with the adjacent part (1a) of the tank shell (1). 7. A tank according to any one of claims 1 to 6, characterized in that it further comprises a tank cover (7) snapped onto the edge of the tank, the tank cover passing through the edge flange ( 6) Engaging at least partially with said flange (3).

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