GB2035430A - Method of manufacturing tubes - Google Patents

Method of manufacturing tubes Download PDF

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Publication number
GB2035430A
GB2035430A GB7928137A GB7928137A GB2035430A GB 2035430 A GB2035430 A GB 2035430A GB 7928137 A GB7928137 A GB 7928137A GB 7928137 A GB7928137 A GB 7928137A GB 2035430 A GB2035430 A GB 2035430A
Authority
GB
United Kingdom
Prior art keywords
tube
metal
injected
expandable
cardboard
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.)
Withdrawn
Application number
GB7928137A
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.)
AMENGUAL ROTGER
Original Assignee
AMENGUAL ROTGER
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 AMENGUAL ROTGER filed Critical AMENGUAL ROTGER
Publication of GB2035430A publication Critical patent/GB2035430A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/22—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/20—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of indefinite length
    • B29C44/32—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements
    • B29C44/322—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements the preformed parts being elongated inserts, e.g. cables
    • B29C44/324—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements the preformed parts being elongated inserts, e.g. cables the preformed parts being tubular or folded to a tubular shape
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L9/00—Rigid pipes
    • F16L9/14—Compound tubes, i.e. made of materials not wholly covered by any one of the preceding groups
    • F16L9/147—Compound tubes, i.e. made of materials not wholly covered by any one of the preceding groups comprising only layers of metal and plastics with or without reinforcement

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Laminated Bodies (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)

Abstract

In manufacturing tubes a portion of steel 1, 2 or cardboard 3, 4 or other material is rolled to form a tube with a simultaneous injection 6, 7 of an expandable synthetic material such as polyurethane polyethylene or PVC. Alternatively the expandable material is injected into the interior of a preformed tube 8. The thus reinforced tube can be provided with an external coating 13, 14 of plastics material and may be cut the lengths 16 and provided with an external or internal threading 17. <IMAGE>

Description

SPECIFICATION Improvements in or relating to a method of manufacturing tubes This invention relates to a method of manufacturing tubes which are internally reinforced with synthetic material and also relates to reinforced tubes when manufactured by such a method.
According to one aspect of this invention there is provided a method of manufacturing a reinforced member, said method comprising the steps of forming a tube, and during or after the step of forming the tube injecting an expandable synthetic material into the space defined in the interior of the tube, the injected material being such that the material will expand reaching a maximum volume after filling the tube, thus lining the interior of the tube.
It is to be appreciated that the tube may be formed of any suitable material such as sheet metal, which may be initially in the form of sheets or a roll, cardboard, which may be initially in the form of sheets or a roll, a laminated material, which may be in the form of sheets or a roll, or a plastics material or a ceramic material.
Preferably the expandable synthetic material is polyurethane, polyethylene or PVC (polyvinyl chloride).
The tubes used in the method of the invention may be cylindrical, oval or may have a square, rectangular or any other cross-section.
Where the tube is formed from a deformed sheet of metal preferably adjacent edges of the metal are connected by welding by resistance or high frequency welding, and preferably the tube is subsequently cooled, calibrated and straightened.
Where a tube in accordance with the invention is formed from cardboard or the like preferably the cardboard, after the expandable material is injected, is formed to shape and is secured by adhesive tape, adhesive or some other system.
Where the tube is formed before the expandable material is injected, and where the tube is of metal, preferably the interior of the tube is thoroughly cleaned before the synthetic material is injected. In such an embodiment the synthetic material may be injected at high pressure at one end of the tube.
Preferably the tube is subsequently covered with one or more layers of rigid, semi-rigid or flexible synthetic material having a desired thickness. The synthetic material may have any desired colour and may be phospherescent. Conveniently the tube may be covered with plastics material by an injector or plastics extruder and may preferably be covered with plastics material having a number of colours.
In such an embodiment the tube surface may be decorated in stripes in various colours of varying widths.
It is to be appreciated that where a tube has been externally coated with plastics material the tube may be conveyed to a polymerization chamber for polymerization of the plastics coating.
It will be appreciated that tubes made by method as described above may be cut to any desired length for transportation purposes, and the tube, if made of metal or plastics material can be provided with internal or external threaded portions at the ends thereof.
This invention also relates to a tube when made by the above described method.
In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described by way of example with reference to the accompanying drawing which is a flow diagram representing various methods of manufacturing reinforced members in accordance with the invention.
The method of the present invention relates to the manufacture of reinforced members which comprise tubes which are reinforced internally with a synthetic plastics material.
In a method in accordance with the present invention various initial starting materials may be utilised. For example, a rolled strip of sheet metal 1, may be utilised or flat cut metal sheets 2, or a rolled strip of cardboard 3, or flat cut lengths of cardboard 4, or alternatively, a tubular member which is formed by winding a spiral from a strip of cardboard or metal. Of course, other materials may be utilised if desired such as laminated synthetic materials laminated paper or any other appropriate substantially flat material.
Where the starting material is a rolled strip of sheet metal, flat cut metal sheets, a strip of rolled cardboard or lengths of cut cardboard or the like the next step in the method in accordance with the invention is to cut the strip or sheet to length, if appropriate, and to roll or otherwise form the sheet or strip into the configuration of a tube, whilst simultaneously injecting expandable material such as polyurethane or polyethylene of PVC (polyvinyl chloride) into the space defined within the tube 6, 7. The injected material expands and hardens in about 10 seconds, and thus adheres tightly to the walls of the tube. It is to be noted that the injected material expands strongly, reaching its maximum volume after filling the tube, thus efficiently lining the interior of the tube.
Immediately after the injecting step it is necessary to weld the seam 9, if the tube is of metal, or to secure the adjacent edges of the sheet defining the tube together 10, by means of adhesive tape, or by means of adhesive or glue if the sheet is of cardboard or similar material. If sheets of metal are utilised it is necessary to weld the adjacent edges of the sheet metal together, and the welding may be performed by resistance welding or high frequency welding, or any other appropriate welding process. Any excess heat supplied is dissipated by a cooling device II.
Subsequently the metal tube may be passed through a calibrating and strengthening device 12.
It is to be appreciated, of course, that where the tube is formed 5 before the expandable material is injected, if the tube is formed of metal it may well prove to be advantageous to clean at least the interior of the tube before the expandable material is injected, at high pressure, at one end of the tube. Any oxide formed on the interior of the tube will be removed during the cleaning process and the interior of the tube will then virtually immediately be covered by the expandable plastics material, thus eliminating oxidation from the interior of the tube.
The intermediate product of all the above described processes comprises a tube that is filled with an expanded reinforcing synthetic material. Irrespective of the precise method utilised in manufacturing the tube, the tube may then be provided with an external coating of a plastics material, and thus the tube may be conveyed to an injector or plastics extruder 13 where it is covered with a single plastics material of a single colour. Alternatively the tube may be conveyed to a multiple injector or plastics extruder 14 where the tube is provided with a coating comprising a number of colours.After leaving the injector or extruder 13 or 14 the tube may either pass through a polymerization chamber where the tube is treated to assist the polymerization of the coating applied to the tube, the tube then passing to a station 16 at which the tube is cut to size for transport or, alternatively, the tube may pass directly from the injector or extruder 13 or 14 to the cutting station 16. If desired the ends of the tubes may be threaded, 17, either internally or externally, and then the tubes may be transported 18 from the factory.
It is to be appreciated that the exterior plastics coating applied to the tube may be rigid or semi-rigid or flexible, and may have any desired thickness. The exterior coating may comprise one or more colours which may be phosphorescent and, where a plurality of colours are provided the colours may be in the form of stripes of various colours and of various widths.
Whilst the invention has been specifically described with reference to embodiments in which the tube is formed of metal or cardboard or laminated material it is to be appreciated that the tube may be formed of any appropriate material such as ceramic or paper derivatives or PVC or similar synthetic substances.
Since the material injected into the tube expands after it has been injected it is envisaged that the reinforcement constituted by the hardened injected material will remain firmly attached to the interior of the tube.
Consequently it will not be necessary to galvanize or paint the interior of the tube. The injected material will serve to increase the mechanical strength of the tube but will facilitate bending of the tube in that it will prevent flattening of the tube during a bending operation. It is to be appreciated that the infection of the expandable material does not significally increase the duration of the tube manufacturing process and only represents a low additional cost. The presence of the reinforcement within the tube will help prevent or minimise corrosion or oxidation on the interior of the tube.
The invention can, of course, be applied to tubes made of metal, cardboard or other material such ceramics and facilitates the subsequent cutting of cardboard, synthetic or similar reinforced tubes.

Claims (17)

1. A method of manufacturing a reinforced member,said method comprising the steps of forming a tube, and during or after the step of forming the tube injecting an expandable synthetic material into the space defined in the interior of the tube, the injected material being such that the material will expand reaching a maximum volume after filling the tube, thus lining the interior of the tube.
2. A method according to claim 1 wherein the tube is formed of sheet metal, cardboard, a laminated material, or a plastics material or a ceramic material.
3. A method according to claim 1 or 2 wherein said expandable synthetic material is polyurethane, polyethylene or PVC (polyvinyl chloride).
4. A method according to any one of the preceding claims wherein the tube is formed from a deformed sheet of metal and adjacent edges of the metal are connected by welding, by resistance or high frequency.
5. A method according to claim 4 wherein, after the welding step, the tube is subsequently cooled, calibrated and straightened.
6. A method according to any one of claims 1 to 3 wherein the tube is formed from cardboard or the like and wherein the cardboard or the like, after the expandable material is injected, is formed to shape and is secured by adhesive tape or adhesive.
7. A method according to any one of claims 1 to 3 wherein a metal tube is formed before the expandable material is injected, comprising the step of clearing the interior of the tube before the synthetic material is injected.
8. A method according to any one of the preceding claims wherein the tube is covered with one or more layers of rigid, semi-rigid or flexible synthetic material having a desired thickness.
9. A method according to claim 8 wherein the synthetic material used to cover the tube is phospherescent.
10. A method according to claim 8 or 9 wherein the tube is covered with plastics material by an injector or plastics extruder.
11. A method according to claim 10 wherein the tube is covered with a plastics material having a number of colours, in stripes of varying widths.
12. A method according to any one of claims 8 to 11 wherein, when the tube has been externally coated with synthetic material the tube is conveyed to a polymerization chamber for polymerizations of the coating.
13. A method according to any one of the preceding claims comprising the step of cutting the tube to a desired length.
14. A method according to any one of the preceding claims wherein the tube made of metal or plastics material comprising the steps of providing the tube with internal or external threaded portions at the ends thereof.
15. A method of making a tube substantially as herein described with reference to the accompanying drawing.
16. A tube whenever made by a method according to any one of the preceding claims.
17. Any novel feature or combination of features disclosed herein.
GB7928137A 1978-08-03 1979-08-13 Method of manufacturing tubes Withdrawn GB2035430A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
ES78472313A ES472313A1 (en) 1978-08-03 1978-08-03 Method of manufacturing tubes

Publications (1)

Publication Number Publication Date
GB2035430A true GB2035430A (en) 1980-06-18

Family

ID=8476613

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7928137A Withdrawn GB2035430A (en) 1978-08-03 1979-08-13 Method of manufacturing tubes

Country Status (5)

Country Link
DE (1) DE2931425A1 (en)
ES (1) ES472313A1 (en)
FR (1) FR2432670A1 (en)
GB (1) GB2035430A (en)
PT (1) PT70011A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2042288A1 (en) * 2007-09-26 2009-04-01 REHAU AG + Co Composite body and method for its manufacture

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI77102C (en) * 1981-05-25 1989-01-10 Kabel Metallwerke Ghh Process for producing a heat insulated conduit
CA2135322C (en) * 1993-11-10 2001-02-06 Hiroshi Sugahara Method for producing a fiber-reinforced thermoplastic resin foamed product
BE1011075A3 (en) * 1997-03-28 1999-04-06 Solvay Forms duct metal jacket tube.

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2042288A1 (en) * 2007-09-26 2009-04-01 REHAU AG + Co Composite body and method for its manufacture

Also Published As

Publication number Publication date
PT70011A (en) 1979-09-01
DE2931425A1 (en) 1980-03-27
ES472313A1 (en) 1979-02-16
FR2432670A1 (en) 1980-02-29

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)