CONVEYING OF PLASTIC BOTTLES

Abstract

A conveying system (1), comprising a modular conveyor belt (2) supported on a conveyor track (3) so that top surfaces (4) of the modules (5) of the conveyor belt present a conveying face (6) that in use moves along the track in a conveying direction, and at least one plastic bottle supported at its bottom on the conveying face via one or more textured surfaces at a bottom of the bottle. The disclosure also includes a method of conveying bottles, wherein plastic bottles are supported with their bottoms on a moving conveying face of a conveyor, and wherein the conveying face and the bottom of the bottle are conveyed via one or more textured surfaces (12) at a bottom of the bottle. The disclosure further includes use of at least one textured bottom surface of a plastic bottle for conveying, and a blow mold for blow molding a plastic bottle.

Claims

1. A conveying system, said conveying system comprising: a plurality of modules forming a modular conveyor belt supported on a conveyor track so that top surfaces of the modules of the conveyor belt present a conveying face that in use moves along the track in a conveying direction; and at least one plastic bottle, said at least one plastic bottle having at least one textured surface and being supported on the conveying face via said at least one textured surface at a bottom of the bottle.

2. The conveying system of claim 1, wherein the at least one plastic bottle is supported on the conveying face via the at least one textured surface free of external lubrication between the at least one plastic bottle and the conveying face.

3. The conveying system of claim 1, wherein the at least one textured surface includes projections that project from one or more base surfaces at the bottom of the at least one plastic bottle.

4. The conveying system of claim 3, wherein the projections engage the conveying face to form together a combined contact area that is smaller than a base area of the engaged projections.

5. The conveying system of any of claim 2, wherein the one or more base surface are part of a bottom wall of the at least one plastic bottle.

6. The conveying system of any of claims 1, wherein the at least one textured surface is a plurality of textured surfaces provided at ends of support feet projecting downward at the bottom of the at least one plastic bottle.

7. The conveying system of claim 1, wherein the at least one textured surface includes polyethylene terephthalate (PET).

8. The conveying system of claim 1, wherein the top surfaces of the modules are made of plastic.

9. The conveying system of claim 1, wherein the top surfaces of the modules are provided with a smooth, nontextured surface.

10. The conveying system of claim 1, wherein the modular conveyor belt is arranged to recirculate between first and second divert elements, a top run of the conveyor extending between the first and second elements and being supported on the conveyor track, so that in the top run, top surfaces of the modules of the conveyor belt present the conveying face that in use moves in the conveying direction from the first divert elements towards the second divert elements.

11. A method of conveying bottles, said method comprising: supporting at least one plastic bottle on a moving conveying face of a conveyor, said at last one plastic bottle having at least one textured surface, wherein the at least one plastic bottle being supported on the conveying face via said at least one textured surface at a bottom of the bottle.

12. The method of claim 11, wherein the at least one plastic bottle is conveyed without external lubrication between the at least one plastic bottle and the conveying face.

13. (canceled)

14. A blow mold for blow molding a bottle, said blow mold comprising: at least two mold parts that in a closed position cooperate to form a cavity defining an outer shape of a bottle, and in an open position allow a bottle to be taken out of the cavity, wherein the cavity is provided with a counterform for providing a textured surface at a part of the cavity corresponding to a bottom of the bottle to be formed.

15. The method of claim 11, in which said conveyor is a modular conveyor belt formed from a plurality of modules supported on a conveyor track so that top surfaces of the modules of the conveyor belt present the conveying face that in use moves along the track in a conveying direction.

Description

[0027] FIG. 1 shows a schematic perspective view of a conveying system presenting a conveying face comprising a plurality of plastic bottles, each supported at its bottom on the conveying face via one or more textured surfaces at the bottom of the bottle,

[0028] FIG. 2 shows a schematic perspective bottom view of a plastic bottle of the system of FIG. 1, and

[0029] FIGS. 3a-3e show a detail of the bottle of FIG. 2 including one of its textured surface.

[0030] It is noted that the figures are merely schematic representations of a preferred embodiment of the invention. In the figures, identical or corresponding parts are represented with the same reference numerals.

[0031] FIG. 1 shows a conveying system 1. The conveying system comprises a modular conveyor belt 2 supported on a conveyor track 3. Top surfaces 4 of the modules 5 of the conveyor belt 2 present a conveying face 6. The conveying face 6 in use moves along the track 3 in a conveying direction, indicated with arrow P. The modular conveyor belt 2 is typically arranged to recirculate between first divert elements and second divert elements. A top run 9 of the conveyor belt 2 then extends between the first and second elements and is supported on the conveyor track 3. The conveying face 6 in use moves in the conveying direction P from the first divert elements towards the second divert elements. The modules 5 of the conveyor belt 2 are in this example made of plastic, and can be injection molded, e.g. from PBT, and the top surfaces of the modules can be provided with a smooth, substantially flat non textured surface.

[0032] The conveying system comprises a plurality of plastic bottles 10. Each bottle is supported at its bottom 11 on the conveying face 6 via a number of textured surfaces 12 at the bottom 11 of the bottle 10. Although the bottle 10 in the embodiments shown here comprises five textured surfaces 12, alternative bottles can comprise more or less than five textured surfaces, e.g. one, two, four or six textured surfaces. The bottles 10 are in this example supported on the conveying face 6 via the textured surfaces 12 free of external lubrication between the bottle 10 and the conveying face 3, i.e. without added lubrication. Hence, dirtying the conveyor system 1, e.g. its conveyor belt 2 and/or dirtying the bottles 10 can be counteracted.

[0033] The bottles 10 in this example are made of PET, and have been blow molded in a mold from a standard injection molded preform. The bottles in this example are 1.5 l carbonated soft drink bottles having a height of about 30 cm, and a base diameter of about 8 cm. The bottles are thin walled, and have a wall thickness of about 0.8 mm at the bottom, and have a volume of 1.5 l. The bottles 10 include downwardly projecting feet 13 at their bottoms. The blow mold used for blow molding the bottles includes two mold halves. In a closed position the mold halves cooperate to form a cavity defining the outer shape of a bottle, and in an open position they are spaced apart to allow a bottle to be taken out of the cavity. In the closed position of the mold, the preform is positioned within the mold cavity, and positioning means position the preform in the cavity, so that it can be blown against the cavity walls to form a bottle. The cavity is provided with a counterformed, inverted texture at a the bottom of the cavity, so as to provide a corresponding textured surface at the bottom of the feet 13 of the bottle 10 to be formed. The texture may be provided in the mold cavity using electronic discharge machining.

[0034] The textured surface 12 is in the example integrally formed with the bottom wall 14 of the bottle 10, and is provided at the extremities of support feet 13 projecting downward at the bottom 11 of the bottle 10.

[0035] As can be seen in FIGS. 3, in particular FIG. 3e, the textured surface 12 includes projections 15 that project from a base surface 16 at the bottom 11 of the bottle 10. The projections 15 are designed to engage the conveying face to together form a combined contact area that is smaller than a base area of the engaged projections, i.e. an area covered by the base surface 16 from which the projections 15 project. In use, fresh plastic bottles 10 are placed on the top run 9 of the conveyor belt 2, and are conveyed in the conveying direction P. The plastic bottles 10 are supported with their bottoms 11 on the moving conveying face 6 of the conveyor 2, and are conveyed via the textured surfaces 12 at the bottom 11 of the bottle 10. The textured surfaces are relatively fresh and clean during conveying. This because in the conveying process, the PET bottles are for example only conveyed for 1-10 minutes on the conveying face 6 formed by the flat, smooth top surfaces 4 of the plastic conveyor modules 5, so that during conveying deterioration of the textured surfaces 12 at the bottom 11 of each bottle 10 is negligible, and the coefficient of friction remains constant at about 0.06-0.18. The friction between the bottles and the conveying face can thus be reliably constant and low, without need for external lubrication.

[0036] The invention is not limited to the exemplary embodiment represented here. For example, the conveyor belt may be embodied as a mat or chain, and may even be of continuous, non modular construction. In addition, the conveyor belt may be part of a series of conveyor belts in the system. The conveyor belt may be made of hard material, e.g. steel or hard plastic, but may also be made of resilient material, e.g. rubber or elastomer. The bottles may have various shapes and sizes, and may be made of many different types of plastic materials, or compositions including plastic. Such variations shall be clear to the skilled person and are considered to fall within the scope of the invention as defined in the appended claims.

LIST OF REFERENCE SIGNS

[0037] 1. Conveying system

[0038] 2. Modular conveyor belt

[0039] 3. Conveyor track

[0040] 4. Top surface of module

[0041] 5. Module

[0042] 6. Conveying face

[0043] 7. First divert elements

[0044] 8. Second divert elements

[0045] 9. Top run

[0046] 10. Plastic bottle

[0047] 11. Bottom

[0048] 12. Textured surface

[0049] 13. Support foot

[0050] 14. Bottom wall

[0051] 15. Projection

[0052] 16. Base surface

[0053] P. Conveying direction