EP0035999A1 - Assembly for extruding pipe - Google Patents

Assembly for extruding pipe

Info

Publication number
EP0035999A1
EP0035999A1 EP80901700A EP80901700A EP0035999A1 EP 0035999 A1 EP0035999 A1 EP 0035999A1 EP 80901700 A EP80901700 A EP 80901700A EP 80901700 A EP80901700 A EP 80901700A EP 0035999 A1 EP0035999 A1 EP 0035999A1
Authority
EP
European Patent Office
Prior art keywords
mandrel
feed screw
cylindrical
annular nozzle
assembly
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Withdrawn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
EP80901700A
Other languages
German (de)
French (fr)
Inventor
Per Boen
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.)
Sonnichsen Rorvalseverket AS
Original Assignee
Sonnichsen Rorvalseverket AS
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 Sonnichsen Rorvalseverket AS filed Critical Sonnichsen Rorvalseverket AS
Publication of EP0035999A1 publication Critical patent/EP0035999A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/30—Extrusion nozzles or dies
    • B29C48/32—Extrusion nozzles or dies with annular openings, e.g. for forming tubular articles
    • B29C48/33—Extrusion nozzles or dies with annular openings, e.g. for forming tubular articles with parts rotatable relative to each other
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/13—Articles with a cross-section varying in the longitudinal direction, e.g. corrugated pipes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2023/00—Tubular articles
    • B29L2023/003—Tubular articles having irregular or rough surfaces

Definitions

  • the present invention relates to an assembly for extruding circular, cylindrical plastic piping, comprising an extruder with a feed screw for transporting and softening the mass, and an annular nozzle with a central mandrel ⁇ which constitutes a circular, cylindrical, coaxial extension of the feed screw.
  • the mandrel is secured centrally by means of spokes fixed in the outer mold section of the annular nozzle.
  • the spokes thus divide the softened plastic, and even though the plastic flows together after having passed the spokes, axial flow lines will arise which can constitute a weakening of the pipe wall. This is a particulax drawback if the pipe is to be subjected to radially-directed pressure, for instance, an internal water pressure. Bursting of the pipes most often occurs along such weakened portions.
  • the purpose of this invention is to produce by extrusion a pipe having external, helical reinforcing ribs and a smooth interior.
  • a pipe having external, helical reinforcing ribs and a smooth interior One has never before been able to produce such pipes by direct extrusion.
  • Such pipes have previously been made in the form of corrugated pipes , a thin-walled pipe being extruded which thereafter is given a corrugated config ⁇ uration downstream of the extruder by means of pressure or
  • a massive pipe having external ribs and a smooth interior confers great advantages in such applicat as, for instance, ground water drainage pipes (sewer pipes) other pipes which must withstand internal pressure. Because the pipe is provided with rein orcing ribs, one can obtain a large savings of plastics material and thus manufacture a le expensive product.
  • a further feature of the invention is that the oute
  • «£ ⁇ JRE OMPI mold section is provided with lubricating means for lubrication of the sliding surface for the plastic. This is naturally needed primarily when the outer mold section has a threaded groove and the plastic is supposed to rotate during its passage through the nozzle.
  • the lubrication can be effected in several differ ⁇ ent ways, as may readily be imagined; for instance, a portion of the nozzle's outer mold might be made of a porous material and the lubricant pressed through this material.
  • the outer mold might also be made of massive metal, with lubrication bores being provided over all or a portion of the outer mold section.
  • a second embodiment of the invention in which the outer mold section is of a straight, circular, cylindrical con ⁇ figuration is characterized in that the rotating mandrel, is provided with helical grooves on its outside surface and that lubrication of the sliding surface is provided on the extension.
  • Such ' pipes can be utilized in connection with a coupling system for pipes having external helical ribs, short lengths of a pipe with an internal ' thread serving as a threaded collar for connecting the pipes.
  • Such pipes could also be used, for instance, as vertical trunk pipes for the sewer lines in houses. Owing to the internal threaded rib, the water will flow along the pipe wall to a greater extent and there will be better airing of the pipes, and noise will be reduced.
  • Figure 1 shows a cross section through an extruder according to the invention for the production of circular, cylindrical pipes with external ribs
  • Figure 2 shows an extruder in accordance with the invention for the production of pipes with internal ribs.
  • the extruder as is conventional, has a feed screw 1 with a surrounding cylindrical housing 2.
  • the annular nozzle of the extruder consists of a stationary outer section 3 * and a mandrel 4.
  • the mandrel 4 is a direct extension of the feed screw 1 and has in Figure 1 the same diameter as the stem 5 of the feed screw.
  • the outer mold section 3 in the annular nozzle has grooves 6 disposed along a helical line, or in other words, a threaded groove.
  • the mold section 3 can be provided in the conventional manner (although this is not show in Figure 1) with a heating device at its first portion (to th left on the drawing1. At the middle portion 7, it can be pro ⁇ vided with a lubricant under pressure for lubricating the slid surface between the stationary mold section and the plastic.
  • the last portion can be provided with water cooling 8.
  • the plastic 9 is transported and softened owing to heat and pressure in the feed screw 1,2.
  • the softened plastic is given a rotary movement by the rotating mandrel 4 , and by suitably adapting the rate of feed and rotation, the plastic mass will be given a helical rotation such that it will be screwed out through the threaded outer mold section, producing a plastic pipe 10 with external ribs 11 and a smooth interior 1
  • Figure 2 shows a modification of the assembly in Figure 1.
  • this assembly too, there is an extruder with a feed screw 1 and cylinder 2.
  • the outer mold section 3' does not have a threaded groove, but has a smooth mold surface 13.
  • the extension 4' is provided with a threaded groove 14. The plastic mass will in this case move rectilinearly out through the annular nozzle while the mandrel 4 1 is screwed through the mass, producing a pipe 15 with inter ⁇ nal ribs 16.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Meat, Egg Or Seafood Products (AREA)

Abstract

Un ensemble d'extrusion de tubes circulaires, cylindriques en plastique, comprend une extrudeuse (1, 2) avec une vis d'alimentation (1) pour transporter et ramollir la masse (9), et un ajutage annulaire avec un mandrin central (4) qui constitue une extension circulaire, cylindrique, coaxiale (4, 4') de la vis d'alimentation (1). La section du moule stationnaire exterieur (3) de l'ajutage annulaire est pourvue d'une ou plusieurs rainures paralleles helicoidales (6), le sens du filetage etant dans le sens de rotation de la vis (1) et du mandrin (4). Le mandrin (4) possede une surface rugueuse ou est pourvu de rainures axiales ou de nervures sur au moins une partie de sa longueur. De plus, un autre ensemble d'extrusion de tubes circulaires, cylindriques, en plastique, comprenant une extrudeuse (1, 2) avec une vis d'alimentation (2) pour transporter et ramollir la masse, et un ajutage annulaire avec un mandrin central qui constitue une extension circulaire cylindrique coaxiale (4, 4') de la vis d'alimentation (2), le mandrin de rotation (4) est pourvu de rainures helicoidales (14) sur sa surface exterieure. La lubrification se fait sur la surface de glissement, et la section de moules stationnaires exterieurs de l'ajutage annulaire est uniformement cylindrique.An extrusion set of circular cylindrical plastic tubes includes an extruder (1, 2) with a feed screw (1) for transporting and softening the mass (9), and an annular nozzle with a central mandrel (4 ) which constitutes a circular, cylindrical, coaxial extension (4, 4 ') of the feed screw (1). The section of the external stationary mold (3) of the annular nozzle is provided with one or more parallel helical grooves (6), the direction of the thread being in the direction of rotation of the screw (1) and the mandrel (4) . The mandrel (4) has a rough surface or is provided with axial grooves or ribs over at least part of its length. In addition, another extrusion set of circular, cylindrical, plastic tubes, comprising an extruder (1, 2) with a feed screw (2) for transporting and softening the mass, and an annular nozzle with a central mandrel which constitutes a coaxial cylindrical circular extension (4, 4 ') of the feed screw (2), the rotation mandrel (4) is provided with helical grooves (14) on its outer surface. Lubrication takes place on the sliding surface, and the section of external stationary molds of the annular nozzle is uniformly cylindrical.

Description

ASSEMBLY FOB EXTRUDING PIPE
The present invention relates to an assembly for extruding circular, cylindrical plastic piping, comprising an extruder with a feed screw for transporting and softening the mass, and an annular nozzle with a central mandrel^ which constitutes a circular, cylindrical, coaxial extension of the feed screw.
In the hitherto known extruders for producing plastic piping, the mandrel is secured centrally by means of spokes fixed in the outer mold section of the annular nozzle. The spokes thus divide the softened plastic, and even though the plastic flows together after having passed the spokes, axial flow lines will arise which can constitute a weakening of the pipe wall. This is a particulax drawback if the pipe is to be subjected to radially-directed pressure, for instance, an internal water pressure. Bursting of the pipes most often occurs along such weakened portions.
The purpose of this invention is to produce by extrusion a pipe having external, helical reinforcing ribs and a smooth interior. One has never before been able to produce such pipes by direct extrusion. Such pipes have previously been made in the form of corrugated pipes , a thin-walled pipe being extruded which thereafter is given a corrugated config¬ uration downstream of the extruder by means of pressure or
OMPI WIPO .Λ, vacuum. The corrugations will then be of the same configur both on the inside and outside of the pipe. Such pipes hav been used as so-called electrician's piping and, for example as drainage pipes. Such pipes, however, are poorly suited f transporting a medium, e.g., as waste pipes, because the resistance of the pipe is. much too great. It has hitherto n been possible to produce pipes with relatively thick walls immediately in extruders. Where there has been a need for p having external ribs and a smooth interior, it has previousl been necessary to extrude a corrugated pipe while at the sam time producing a smooth-walled pipe in a second extruder. T two pipes are then formed and welded together in a common to complex with the corrugated pipe lying outside the smooth pi Another method is to machine the outer surface of the pipe w cutting tools. Both of these methods are naturally costly a are suited only for certain types of plastics.
A massive pipe having external ribs and a smooth interior, however, confers great advantages in such applicat as, for instance, ground water drainage pipes (sewer pipes) other pipes which must withstand internal pressure. Because the pipe is provided with rein orcing ribs, one can obtain a large savings of plastics material and thus manufacture a le expensive product.
This is obtained in accordance with the invention by the assembly mentioned in the introduction to the specifi¬ cation, which is characterized in that the stationary outer mold section of the annular nozzle is provided with one or more parallel, helical grooves,_with the direction of the thread being in the direction of rotation of the screw and mandrel. It is a further feature of the invention, that the outside surface of the rotating mandrel is roughened or pro¬ vided with axial grooves or ribs over at least a portion of i length. By means of this feature, the mandrel or extension w more easily carry the plastic mass along and bring it into rotation. In order to obtain a satisfactorily smooth interio surface on the pipe, it is a feature of the invention that th outer portion of the mandrel is smooth.
A further feature of the invention is that the oute
«£\JRE OMPI mold section is provided with lubricating means for lubrication of the sliding surface for the plastic. This is naturally needed primarily when the outer mold section has a threaded groove and the plastic is supposed to rotate during its passage through the nozzle. The lubrication can be effected in several differ¬ ent ways, as may readily be imagined; for instance, a portion of the nozzle's outer mold might be made of a porous material and the lubricant pressed through this material. The outer mold might also be made of massive metal, with lubrication bores being provided over all or a portion of the outer mold section.
A second embodiment of the invention in which the outer mold section is of a straight, circular, cylindrical con¬ figuration is characterized in that the rotating mandrel, is provided with helical grooves on its outside surface and that lubrication of the sliding surface is provided on the extension. With this modification, one can produce pipes having a smooth exterior surface and a ribbed interior. Such' pipes can be utilized in connection with a coupling system for pipes having external helical ribs, short lengths of a pipe with an internal' thread serving as a threaded collar for connecting the pipes. Such pipes could also be used, for instance, as vertical trunk pipes for the sewer lines in houses. Owing to the internal threaded rib, the water will flow along the pipe wall to a greater extent and there will be better airing of the pipes, and noise will be reduced.
The invention will be elucidated further hereinbelow with reference to the accompanying schematic illustrations, where ___
Figure 1 shows a cross section through an extruder according to the invention for the production of circular, cylindrical pipes with external ribs, and
Figure 2 shows an extruder in accordance with the invention for the production of pipes with internal ribs.
The extruder, as is conventional, has a feed screw 1 with a surrounding cylindrical housing 2. The annular nozzle of the extruder consists of a stationary outer section 3* and a mandrel 4. The mandrel 4 is a direct extension of the feed screw 1 and has in Figure 1 the same diameter as the stem 5 of the feed screw. In Figure 1, the outer mold section 3 in the annular nozzle has grooves 6 disposed along a helical line, or in other words, a threaded groove. The mold section 3 can be provided in the conventional manner (although this is not show in Figure 1) with a heating device at its first portion (to th left on the drawing1. At the middle portion 7, it can be pro¬ vided with a lubricant under pressure for lubricating the slid surface between the stationary mold section and the plastic. The last portion can be provided with water cooling 8.
The plastic 9 is transported and softened owing to heat and pressure in the feed screw 1,2. The softened plastic is given a rotary movement by the rotating mandrel 4 , and by suitably adapting the rate of feed and rotation, the plastic mass will be given a helical rotation such that it will be screwed out through the threaded outer mold section, producing a plastic pipe 10 with external ribs 11 and a smooth interior 1
Figure 2 shows a modification of the assembly in Figure 1. In this assembly, too, there is an extruder with a feed screw 1 and cylinder 2. Here, however, the outer mold section 3' does not have a threaded groove, but has a smooth mold surface 13. Conversely, the extension 4' is provided with a threaded groove 14. The plastic mass will in this case move rectilinearly out through the annular nozzle while the mandrel 41 is screwed through the mass, producing a pipe 15 with inter¬ nal ribs 16.

Claims

1. An assembly for extruding circular, cylindrical plastic piping, comprising an extruder (1,21 with a feed screw (2) for transporting and softening the mass (91, and an annular nozzle with a central mandrel (4). -which constitutes a circular, cylin¬ drical, coaxial extension (4, 4'1 of the feed screw (2), characterized in that the stationary outer mold section (3) of the annular nozzle is provided with one or more parallel, helical grooves (6) , with the direction of the thread being in the direction of rotation for the screw (l)and mandrel (4) .
2. An assembly as claimed in claim 1, characterized in that the mandrel (4)"has a roughened surface or is provided with axial grooves or low ribs over at least a portion of its length.
3. - - An assembly as claimed in claim 2, characterized in that the outer portion is smooth.
4. An assembly as claimed in one or more of the preceding claims, characterized in that the outer mold section (3) is provided with lubrication means (71 for lubricating the sliding surface for the plastic.
5. An assembly as claimed in one or more of the preceding claims, characterized in that the outer portion of the outer mold section, in a manner known per se, is water cooled (8) .
6. An alternate assembly for extruding circular, cylin¬ drical plastic piping, comprising an extruder (1,2) with a feed screw (2) for transporting and softening the mass, and an annular nozzle with a central mandrel which constitutes a circular, cylindrical, coaxial extension (4, 4') of the feed screw (2), characterized in that the rotating mandrel (41) is provided with helical grooves (14) on its outside surface and that lubrication is provided on the sliding surface, and that the stationary outer mold section of the annular nozzle is smoothly cylindrical.
OMPI
EP80901700A 1979-09-28 1981-04-08 Assembly for extruding pipe Withdrawn EP0035999A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO793128 1979-09-28
NO793128A NO793128L (en) 1979-09-28 1979-09-28 DEVICE FOR EXTRUSION OF ROES.

Publications (1)

Publication Number Publication Date
EP0035999A1 true EP0035999A1 (en) 1981-09-23

Family

ID=19885063

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80901700A Withdrawn EP0035999A1 (en) 1979-09-28 1981-04-08 Assembly for extruding pipe

Country Status (11)

Country Link
EP (1) EP0035999A1 (en)
JP (1) JPS56501237A (en)
AR (1) AR222724A1 (en)
BE (1) BE885352A (en)
BR (1) BR8008849A (en)
DK (1) DK226781A (en)
FI (1) FI802996A (en)
IT (1) IT1154744B (en)
NO (1) NO793128L (en)
RO (1) RO88508A (en)
WO (1) WO1981000823A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2212256B (en) * 1987-11-12 1992-04-22 James Gray Improvements in and relating to heat exchangers
WO2016005810A1 (en) * 2014-07-10 2016-01-14 Zehnder Group International Ag Tube bank for a heating element or a cooling element

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB618536A (en) * 1946-07-30 1949-02-23 Bx Plastics Ltd Improvements in or relating to extrusion apparatus
FR1308929A (en) * 1961-12-26 1962-11-09 Union Carbide Corp Finned tubes, and their manufacturing process
US3496605A (en) * 1965-10-26 1970-02-24 Yasuyoshi Onaka Apparatus for extruding ribbed plastic pipe
CH472957A (en) * 1967-04-26 1969-05-31 Agk Betr Sgesellschaft Ag Seepage or drainage pipe made of plastic, method for producing such a pipe and device for carrying out the method
JPS5240337B2 (en) * 1973-01-29 1977-10-12
US4053274A (en) * 1975-01-28 1977-10-11 Lemelson Jerome H Tube wall forming apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8100823A1 *

Also Published As

Publication number Publication date
DK226781A (en) 1981-05-22
IT1154744B (en) 1987-01-21
BE885352A (en) 1981-01-16
BR8008849A (en) 1981-07-21
WO1981000823A1 (en) 1981-04-02
IT8083441A0 (en) 1980-09-26
NO793128L (en) 1981-03-31
RO88508A (en) 1986-02-28
JPS56501237A (en) 1981-09-03
FI802996A (en) 1981-03-29
AR222724A1 (en) 1981-06-15

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19810518

AK Designated contracting states

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STAA Information on the status of an ep patent application or granted ep patent

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18D Application deemed to be withdrawn

Effective date: 19830410

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Inventor name: BOEN, PER