EP0838405A1 - Container and blowing mould for production of the same - Google Patents

Container and blowing mould for production of the same Download PDF

Info

Publication number
EP0838405A1
EP0838405A1 EP97850099A EP97850099A EP0838405A1 EP 0838405 A1 EP0838405 A1 EP 0838405A1 EP 97850099 A EP97850099 A EP 97850099A EP 97850099 A EP97850099 A EP 97850099A EP 0838405 A1 EP0838405 A1 EP 0838405A1
Authority
EP
European Patent Office
Prior art keywords
container
bottom portion
point
wall
blowing mould
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP97850099A
Other languages
German (de)
English (en)
French (fr)
Inventor
Mikael Quasters
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rexam AB
Original Assignee
PLM AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by PLM AB filed Critical PLM AB
Publication of EP0838405A1 publication Critical patent/EP0838405A1/en
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D1/00—Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material
    • B65D1/02—Bottles or similar containers with necks or like restricted apertures, designed for pouring contents
    • B65D1/0223—Bottles or similar containers with necks or like restricted apertures, designed for pouring contents characterised by shape
    • B65D1/0261—Bottom construction
    • B65D1/0276—Bottom construction having a continuous contact surface, e.g. Champagne-type bottom

Definitions

  • the present invention relates to a container, especially for drinks, of the type defined in the preamble to claim 1.
  • the invention also concerns a blowing mould for producing such a container.
  • the invention is particularly, but not exclusively, directed to blow-moulded bottles of a plastic material, which are refillable and intended for aerated soft drinks.
  • Examples of such bottles are disclosed in e.g. EP-A-0 521 841 and EP-A-0 247 566. This kind of bottle is thus produced from a preform which is heated and blow-moulded to a finished bottle.
  • Refillable containers of the above-mentioned type must be inspected after each filling operation for detecting impurities or cracking in the container bottom.
  • Equipment for such inspection is disclosed in e.g. EP-A-0 647 846, which describes a method for inspecting a transparent container having a bottom which curves to the interior of the container.
  • the container is arranged between a direct or indirect light source and a detector, which is a digital camera, a so-called CCD camera.
  • the light source illuminates the bottom of the container, which thus is penetrated by light, and part of the light passing through the container is caught by the detector, which registers this light as an image.
  • Defects in the bottom such as cracks, or impurities on the bottom inside the container, such as liquid or particles, deflect the incident light and thus result in small amounts of light reaching the detector from these areas.
  • the resulting image therefore presents darker portions in the area of a defect or an impurity.
  • this image is digitised at a number of intensity levels, whereupon the image is processed in a computer assigned to the camera.
  • a threshold value in respect of the intensity levels of the image, the threshold value being selected so that the container is considered unacceptable if the intensity of light within an area of the image is less than this threshold value. If the intensity of light over the entire image or a selected part thereof is greater than the threshold value, the container is determined to be acceptable.
  • containers of the above-mentioned type must be washed, which usually takes place in an alkaline solution and at a temperature of about 58-60°C.
  • the higher temperature used the better washing result, but the plastic material implies restrictions.
  • the market demands containers that withstand washing temperatures of up to about 75°C.
  • the object of the invention is to provide a container that withstands temperatures of up to about 75°C and has improved strength in its bottom portion and which can be inspected by radiation of the bottom of the container.
  • the container bottom will obtain improved strength compared with corresponding prior-art bottom constructions.
  • the internal pressure that may prevail inside the container and that is established, for instance, when filling the container with an aerated soft drink, is efficiently counteracted in the inventive container by the modified bottom with an annular reinforcement in the transition between the curved portions.
  • Fig. 1 illustrates an example of an arrangement, as described by way of introduction, for inspecting an arbitrary container 1, the container being shown in cross-section for reasons of clarity.
  • the container 1 has a transparent bottom 2, a body 3 which is extended from the bottom 2 and passes into an opening 4.
  • the invention is particularly directed to containers for drinks, and the container shown in Fig. 1 may be, for instance, a refillable bottle of thermoplastic material, intended for aerated drinks.
  • the container 1 is arranged between a light source 5, which illuminates the bottom 2 of the container 1, and a detector 6, e.g. an electronic camera, which registers light passing through the bottom 2.
  • the bottom 2 of the container 1 is preferably illuminated for a short space of time, for example by making the light source 5 generate a flash of light.
  • the light rays passing through the bottom 2 of the container 1 and falling on the detector 6 are registered by the detector in the form of an image.
  • Fig. 2 is a sectional view of the lower part of a container 1 which is designed according to the invention.
  • the bottom 2 of the container 1 has a first wall portion 7, a so-called dome, which curves to the interior of the container 1.
  • the dome 7 is formed coaxially with the longitudinal centre axis 8 of the container 1, and the outer circumference of the dome 7 substantially coincides with the outer circumference of the bottom 2.
  • the bottom 2 has a second dome 9, which curves to the interior of the container 1 and which is formed coaxially with and within the first dome 7.
  • Fig. 2 shows how three essentially parallel rays of light S1, S2, S3, which fall on the outside of the bottom 2, pass through the material of the bottom and leave the inside of the bottom 2.
  • the designations used henceforth will be explained below in connection with the ray S1 in Fig. 2.
  • the ray S1 falls on the outside of the bottom 2 at the point a at an angle of incidence ⁇ relative to the normal to the wall surface at this point.
  • n 1 sin ⁇ n D sin ⁇ , where n 1 is the refractive index ( ⁇ 1) of the air on the outside of the container 1, n D is the refractive index of the material of the container at the point a, and ⁇ is the refractive angle in relation to the normal to the wall surface at the point a.
  • This ray S1 passes on in the material and falls on the boundary layer towards the interior of the container 1 at the point b at the angle of incidence ⁇ , whereupon it is refracted according to the refraction law. If the wall surfaces of the bottom 2 are parallel at the points a and b, the angles ⁇ and ⁇ are the same, and therefore the ray leaving the inside of the bottom 2 is parallel with the incident light ray. If this is not the case, and if the light ray experiences an increased inclination at the point b compared with the one at the point a, ⁇ will be greater than ⁇ .
  • creased inclination for a surface is meant a surface which is more parallel with the centre axis 8.
  • the ray S1' arrives at too steep a portion of the bottom 2 of the container 1 and therefore experiences such a great increase ⁇ of the inclination between the wall surface of the bottom 2 at the point a and the wall surface of the bottom 2 at the point b that the condition for total reflection is satisfied at the point b, and therefore the ray S1' does not reach the detector 6, which registers a dark annular portion in the area of the second dome 9.
  • Fig. 3a besides suffers from the drawback that the outside of the bottom 2 in the area of the second dome 10 is essentially parallel with the centre axis 8 of the container 1. This results in only a fraction of the incident ray S1' being refracted into the material in this steep area, whereas the main part of the radiation will be reflected towards the outside of the bottom 2 since the reflectance of a surface is essentially equal to 1 for angles of incidence close to 90°. This contributes to the detector 6 registering a dark annular portion in the area of the second dome 9. According to a preferred embodiment, the outside of the bottom portion 2 therefore is formed with an inclination which all over exceeds about 10° relative to the centre axis 8.
  • Fig. 3b shows a further examples of a container which is not designed according to the invention.
  • the wall thickness of the bottom 2 increases in the direction of the centre axis 8, and therefore the incident ray S1" experiences such an increased inclination ⁇ between the points a and b that total reflection arises at the point b.
  • the detector 6 thus registers a dark portion which cannot be distinguished from impurities on the bottom surface and which prevents the demonstration of defects in the actual material of the bottom.
  • thermoplastic materials for the production of a container according to the invention are e.g. polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP) or polyamide (PA). Of course, also mixtures of different plastic materials can be used.
  • the invention is also not connected to the use of a particular method for radiation of the bottom of the container.
  • the most important thing is that defects and/or impurities can be demonstrated in such a radiation, preferably as dark portions.
  • the method of inspection may utilise either directed or diffuse radiation.
  • the invention also concerns a blowing mould (not shown) for producing a container of the above-mentioned type.
  • the mould comprises a first curved portion for moulding the first dome 7 (cf. Fig. 2), and a second curved portion, which is formed within and coaxially with the first portion and which is adapted to mould the second dome 9.
  • the outside of the blowing mould is inclined in relation to a centre axis of the blowing mould.

Landscapes

  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Containers Having Bodies Formed In One Piece (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
EP97850099A 1996-06-27 1997-06-19 Container and blowing mould for production of the same Ceased EP0838405A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9602551 1996-06-27
SE9602551A SE509009C2 (sv) 1996-06-27 1996-06-27 Återfyllbar behållare med transparent bottenparti som inspekteras genom genomlysning

Publications (1)

Publication Number Publication Date
EP0838405A1 true EP0838405A1 (en) 1998-04-29

Family

ID=20403190

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97850099A Ceased EP0838405A1 (en) 1996-06-27 1997-06-19 Container and blowing mould for production of the same

Country Status (4)

Country Link
EP (1) EP0838405A1 (sv)
CZ (1) CZ200697A3 (sv)
NO (1) NO972965L (sv)
SE (1) SE509009C2 (sv)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016217825A (ja) * 2015-05-19 2016-12-22 キリンテクノシステム株式会社 容器検査装置及び検査方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2807185A1 (de) * 1977-03-02 1978-09-07 Solvay Hohlkoerper aus thermoplastischem kunststoff
WO1995006593A1 (en) * 1993-09-02 1995-03-09 Rhodia-Ster Fipack S/A. A plastic bottle for hot filling
WO1995025041A1 (fr) * 1994-03-16 1995-09-21 Societe Anonyme Des Eaux Minerales D'evian Bouteille moulee en matiere plastique et moule de fabrication

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2807185A1 (de) * 1977-03-02 1978-09-07 Solvay Hohlkoerper aus thermoplastischem kunststoff
WO1995006593A1 (en) * 1993-09-02 1995-03-09 Rhodia-Ster Fipack S/A. A plastic bottle for hot filling
WO1995025041A1 (fr) * 1994-03-16 1995-09-21 Societe Anonyme Des Eaux Minerales D'evian Bouteille moulee en matiere plastique et moule de fabrication

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016217825A (ja) * 2015-05-19 2016-12-22 キリンテクノシステム株式会社 容器検査装置及び検査方法

Also Published As

Publication number Publication date
NO972965D0 (no) 1997-06-25
SE9602551D0 (sv) 1996-06-27
SE9602551L (sv) 1997-12-28
CZ200697A3 (cs) 1998-01-14
SE509009C2 (sv) 1998-11-23
NO972965L (no) 1997-12-29

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