Holder for a fluid product and method for producing such a holder

Abstract

Method for forming a holder (1), by blow moulding, with a wall (3), whereby a preform is pushed against a first and second mould part (10, 11) to form an intermediate form, in which the second mould part (11) is moved and takes the intermediate form with it in order to form an edge (5) between the first and second mould part (10, 11), whereby the mould parts (10, 11) are such that the edge (5) includes a first and second edge part (13, 14)), of which the second (14) is closer to the wall (3) than the first, of which the first (13) makes an angle () to the direction of movement of the second mould part (11) and of which the second (14) makes a larger angle () to it.

Claims

1. A holder for a fluid product, the holder comprising: a wall configured to form a storage space for the product; and an edge, formed integrally with the wall, protruding outside the wall, the edge consisting of three straight edge parts, from top to bottom, a first edge part having a first edge length L1, a second edge part having a second edge length L2, and a third edge part having a third edge length L3, the edge extending over a distance D=L1+L2+L3, the second edge part being closer to the wall than the first edge part, the first edge part making a first angle to a central longitudinal axis of the holder, the second edge part making a larger angle to the longitudinal axis than the first angle to the longitudinal axis, the first edge part making the first angle to the longitudinal axis greater than 10, the first edge part and the second edge part connecting, the first edge part and the second edge part being straight in a vertical cross-section, the second edge part connecting to the wall via the third edge part that is shorter than the second edge part, wherein the holder is manufactured by blow molding, making use of a mold with at least a first mold part and a second mold part, the second mold part moving during manufacture such that the edge is formed in a space between the first mold part and the second mold part.

2. The holder according to claim 1, wherein the first edge part is at a free end of the edge.

3. The holder according to claim 2, wherein the distance between the location at which the edge connects to the wall and the free end of the edge is at least 20 mm and a maximum of 70 mm.

4. The holder according to claim 2, wherein the second edge part extends over at least 12% and a maximum of 35% of the distance between the location at which the edge connects to the wall and the free end of the edge.

5. The holder according to claim 2, wherein the first edge part extends over at least 15% and a maximum of 85% of the distance between the location at which the edge connects to the wall and the free end of the edge.

6. The holder according to claim 1, wherein the first edge part makes an angle of between 70 and 115 to the wall at the location at which the edge connects to the wall.

7. The holder according to claim 1, wherein the second edge part makes an angle of between 10 and 50 to the wall at the location at which the edge connects to the wall.

8. The holder according to claim 1, wherein the wall extends on both sides of the edge.

9. The holder according to claim 1, wherein the second edge part makes the larger angle of greater than 80 to the longitudinal axis.

10. The holder according to claim 1, wherein the holder is configured to hold a fluid that is at an overpressure of 1 bar or more.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) With the intention of better showing the characteristics of the invention, a preferred embodiment of a holder according to the invention and a method according to the invention are described hereinafter by way of an example, without any limiting nature, with reference to the accompanying drawings, wherein:

(2) FIG. 1 shows a cross-section of a conventional holder for fluid;

(3) FIG. 2 shows the part of FIG. 1 indicated by F2 on a larger scale;

(4) FIGS. 3 to 5 show successive states of the manufacture of the part of the holder of FIG. 1 shown in FIG. 2;

(5) FIG. 6 shows a cross-section of a holder for fluid according to the invention;

(6) FIG. 7 shows the part of FIG. 6 indicated by F7 on a larger scale;

(7) FIG. 8 shows the part of FIG. 7 indicated by F8 on a larger scale and without shading; and

(8) FIGS. 9 to 11 show successive states of the manufacture of the part of the holder of FIG. 6 shown in FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(9) The holder 1 shown in FIGS. 1 and 2 is a keg for beer and is thus intended to be at an overpressure of approximately to 5 bar during use. The holder 1 has a vertical longitudinal axis L and has a round shape in the cross-section perpendicular to this longitudinal axis L.

(10) The holder 1 comprises a storage space 2 for a fluid. This storage space 2 is formed and defined by the wall 3 of the holder. The storage space 2 is provided with a mouth 4 on the top, on which a tap installation can be connected.

(11) The holder 1 is provided with a base to place the holder 1 stably on a support. This base is formed by an edge 5 that protrudes obliquely downwards from the wall 3, at the underside of the holder 1, at an angle of approximately 90 to the wall and an angle of approximately 30 to the longitudinal axis.

(12) The wall 3 and the edge 5 are made of polypropylene and are integrated, thus formed from one part.

(13) An undesired consequence of the manufacture is that the holder 1 has a thickening 6 on the inside of the wall 3, close to the point where the edge 5 protrudes outside the wall 3. Next to this thickening 6 there is a constriction 7. The point of attachment of the edge 5 on the wall 3 turns out to be the weakest point of the holder 1 in practice.

(14) Such a holder 1 is produced by blow moulding. This is done in an orientation and direction in which the holder 1 is produced with the mouth 4 downwards and thus the base upwards.

(15) To this end, a polypropylene 8 shell is produced in a known way by means of an extruder that acts as a preform for the holder 1. This shell is at such a temperature that the polypropylene 8 is plastic. The formed shell is squeezed closed on its top so that it is only open on the underside.

(16) The shell is then placed in a mould 9 and its underside, with the part that will form the mouth 4, is pushed around a compressed air inlet pipe. Then as a result of the introduction of compressed air the shell is pushed against the mould 9, so that the polypropylene 8 takes on the shape of the mould. This situation is shown in FIG. 3. The plastic mass of polypropylene 8 hereby forms an intermediate form for the manufacture of the holder 1.

(17) This is the case because the mould 9 comprises a first mould part 10 and a second mould part 11, whereby the second mould part 11 is movable with respect to the first mould part 10 and is not yet in the position in which the first mould part 10 and the second mould part 11 together define the desired shape of the holder 1.

(18) Simultaneously or immediately after the shell is placed under pressure, the second mould part 11 is pushed vertically downwards towards the inside, i.e. inwards to the mould cavity. Hereby the mould parts 10, 11 are formed such that in the end position of the second mould part 11, i.e. at the end of its movement, the desired shape of the holder 1 is obtained by the combined mould parts 10, 11. The position of the mould parts 11 and the polypropylene 8 in this end position is shown in FIG. 5, whereby FIG. 4 shows an intermediate position.

(19) Hereby, in the said end position, a space 12 is provided between the first mould part 10 and the second mould part that corresponds to the desired shape of the base. During the movement of the second mould part 11, this space 12 becomes increasingly small as shown in the sequence of FIGS. 3,4 and 5, so that a part of the polypropylene 8 in this space 12 is squeezed out of it and forms the thickening 6 on the inside of the wall 3.

(20) Due to the flow characteristics of the polypropylene 8, combined with gravity, the constriction 7 is also formed.

(21) The mould 9 is cooled, so that through contact between the mould 9 and the polypropylene 8, this last-mentioned cools and solidifies.

(22) The said first mould part 10 and second mould part 11 normally each consist of a number of sub-parts, which can be left undiscussed for the purpose of the present invention. For example, as is well known in the art, the first mould part 10 is made to open sideways in at least two sub-parts, firstly to push the polypropylene 8 around the inlet pipe so that it fits well, and also to be able to take the holder 1 out of the mould 9 after manufacture.

(23) The holder 1 according to the invention, as shown in FIGS. 6 and 7, differs from the holder 1 described above in the following way.

(24) In this case the protruding edge 5 that forms the base consists of three straight edge parts, i.e. from top to bottom a first edge part 13, a second edge part 14, and a third edge part 15.

(25) The first edge part 13 runs obliquely downwards away from the wall of the holder 1, at an angle of approximately 90 to it, and at an angle of approximately 30 to the longitudinal axis L. The second edge part 14 runs horizontally, thus at an angle to the longitudinal axis L that is greater than the first-mentioned angle , and more specifically is 90 in this example.

(26) The third edge part 15 is a very short edge part, with a non-constant thickness so that a distinct angle to the longitudinal axis L cannot be defined, nor is it important. This third edge part 15 can also be considered as a transitional part between the second edge part 14 and the wall 3.

(27) In this holder 1 according to the invention, there is also a thickening 16 of the wall 3 on the inside of the wall 3 at the location of the attachment of the edge 5. However, this thickening 16 is not as thick and is more spread out, compared to the thickenings 6 in the known holders 1. This thickening 16 is not accompanied by a constriction either.

(28) The length L1 of the first edge part 13 is 35 mm, measured over the centre of this first edge part from the free end 17 of the edge 5, as shown in FIG. 8.

(29) The length L2 of the second edge part 14 is 11 mm, also measured over the centre of this second edge part 14, also shown in FIG. 8.

(30) The length L3 of the third edge part 15 is 5 mm, measured from the connection with the second edge part 14 to the projection 18 of the wall 3 at the location of the edge 5.

(31) This means that the distance L1+L2+L3 over which the edge 5 extends, from the location where the edge 5 connects to the wall 3 and the free end 17 of the edge 5, is 51 mm.

(32) The first edge part 13 makes an angle of 86 to the wall 3 at the location where the edge 5 connects to the wall 3.

(33) The second edge part 14 makes an angle of 24 to the wall 3 at the location where the edge 5 connects to the wall 3.

(34) The holder 1 shown in FIGS. 6 and 7 has no appreciable weakening at the place of attachment of the edge 5 to the wall 3.

(35) The producing method of a holder 1 according to the invention, as shown in FIGS. 8 to 10, only differs from the method described above by the mould parts 10, 11 having a different shape, corresponding to the desired shape of the holder 1.

(36) This shows that due to the changed flow direction and flow velocity of the polypropylene 8 that is pushed out of the space between the first mould part 10 and the second mould part 11, combined with gravity, the excessive thickening 6 and constriction 7 of the known method do not occur, but that this polypropylene 8 spreads out relatively evenly.

(37) The present invention is by no means limited to the embodiment described as an example and shown in the drawings, but such a method and holder can be realised according to different variants without departing from the scope of the invention.