DE2359746A1 - METHOD FOR MANUFACTURING PIPE ELBOWS FROM THERMOPLASTIC PLASTIC AND DEVICE FOR CARRYING OUT THE METHOD - Google Patents

Description

DipL-Ing. E E. Finkener - Granges Essern Plast A / S, Storgaten 7o, Dipl.-Ing. W. Emesti N-39OO Porsgrunn, Norway

Patent attorneys - ~ - "-

463 Bochum _x

.Heinrieh-KBrdg-Strasse 12

Femspred \ er «I550,42327. '.''-, Telegram address: Radipatent Bodium

73 168

Process for the production of pipe bends from thermoplastic material and device for. Implementation of the procedure "· - ' -

The invention relates to a method for producing Elbows made of thermoplastic material with essentially constant wall thickness and with a ratio large diameter to the radius of curvature of the pipe bend. Furthermore "the invention relates to a device for Implementation of the procedure.

Several methods of manufacturing pipe bends are already known. Among the most commonly used procedures the pipe bends are welded from segments. These methods incur high labor costs because they are common must be done by hand; in addition, the control of the weld seams causes difficulties. With another known method is a straight pipe as Aus ^. used material that is heated and then bent. However, this method has the disadvantage that Additional stresses occur in the pipe bend - and different Wall thicknesses arise. .

Another way of making elbows is this Injection molding. Elbows made by injection molding usually have smaller dimensions. Since the pipe bends "are often welded to extruded pipes, it is it is necessary to use an extrusion-quality material. However, this makes them difficult to manufacture. Furthermore has shown in practice that the quality of injection molded plastic pipe bends in extrusion quality increases

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is bad to the application of such elbows for Allow pressure pipe systems.

■ From the DT-PS 529 54-8 is a method for production of curved hoses or pipes of uniform wall thickness known. This process uses an extrusion head and the curvature of the extruded tube achieved by braking or compressing the extrusion mass at certain points on the circumference. This is going through Narrowing of the passage cross-section brought about in front of the nozzle opening. The uneven material speed is intended to cause the extruded tube to be bent outside the nozzle opening depending on the speed distribution.

The known from the aforementioned patent method requires an apparatus that is both impractical as is also complicated because a special tool is required for each individual pipe dimension. It is also for Every tool type and for every pipe dimension a series of run-in tests and adjustments to the tool parts necessary before the desired curvature and wall thickness of the product can be achieved. this leads to Additional costs "in purchasing the parts that make up the device, apart from the labor costs associated with Retraction of the device are relatively high. In addition, it is doubtful whether the known device readily can be used for the production of pipe bends made of thermoplastic material, since the production of thermoplastic Products usually require further measures, e.g. in terms of cooling technology.

The NO-PS 1o7 o62 describes a plastic semi-finished product for stiffening rings for table-top devices, whereby according to the teaching of this patent specification the product is a helical, should be extruded hollow strand. In this product, the diameter of the strand is small in relation to the Diameter of the helix. It's in this reference

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nothing says about how this semi-finished product is made will. Since it does not seem to have an exact curvature, to an exact diameter and an exact wall thickness' of the strand arrives, .can. use the information in these parts of the literature cannot be used to produce pipe bends.

The invention is based on the object of a method for Manufacture of elbows made of thermoplastic material to develop with which it is possible to produce elbows with large Manufacture pipe diameters with good quality and relatively inexpensive manufacturing costs. Still pursued the invention aims to provide a simple device for Implementation of the procedure to create.

The aforementioned object is achieved according to the invention in that in a pipe extrusion head, its mandrel and its nozzle in a manner known per se in relation to one another are eccentric, a pipe with different wall thicknesses, but with a uniform width around the nozzle opening of the Extrusion head around distributed outlet speed is extruded and that the tube is directly in a cooling jacket is introduced with the desired constant curvature, with that jacket area of the pipe that is in the nozzle opening shows the greatest wall thickness, the greatest. Radius of curvature receives in the cooling jacket, so: that in the cooling jacket a Elbow with the desired curvature and essentially constant wall thickness is created.

According to a development of the invention it is provided that the curved pipe emerging from the cooling jacket is pulled out by a pulling device with pulling wheels, whose circumferential speed corresponds to the radius of curvature of the surface line of the pipe on which the respective wheel rests, is adapted.

Another development of the invention bestfct that the curved pipe emerging from the cooling jacket is bent in a direction at right angles to the plane of curvature,

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so that a continuous helical E-ear is extruded, which is separated at the desired angular distances to form finished bends.

A device for carrying out the method with an Eohrstrangpreßkopf, its mandrel and its nozzle in the ratio- ' nis can be adjusted eccentrically to each other, is designed according to the invention so that a curved cooling jacket adapted to the extrusion head and associated with the cooling jacket a drawing device for curved tubes.

Compartment of a further development of the invention contains the pulling device Pulling wheels whose circumferential speeds are adapted to the bending radii and diameters of the curved tube can be.

Further details and advantages of the invention are provided below explained in more detail using an embodiment shown in the drawing. Show it;

FIG. 1 shows a longitudinal section of a device according to the invention for producing pipe bends and Figure 2 is a side view of the device.

1 shows an extrusion screw 1 which is rotatable about its horizontal longitudinal axis in a cylinder 2 is stored. The cylinder 2 is connected to a drill extrusion head 3, with interconnected between them a perforated disk 2 'is provided. The extrusion head 3 consists of a fixedly arranged funnel-shaped Tool holder 3 · '· »a torpedo-shaped mandrel 4, which is attached to the tool holder 3' by a mandrel holder with a holding frame 5 is attached, and a funnel-shaped tool nozzle 8. An air duct 6 extends through one. Inlet nozzle 7? through one of the holding arms 5 and further radial in the. Thorn 4- in to its center and from there along the longitudinal axis to the end of the mandrel.

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The nozzle 8 is adjustable on the tool holder 3 '. It is by a pressure ring 9, which is not shown with Fastening organs is pressed against an outer extension 1o on the nozzle 8, held in place, wherein the front edge 11 is held by friction on an inner shoulder 12 in the tool holder 3 '. The mandrel 4 is in the embodiment by means of the holding arms 5 in its location set while the nozzle 8 in proportion to the mandrel 4 is eccentric adjustable. Let through it Different widths of the gap 13, which is annular in cross section, are set between the mandrel 4 and the nozzle 8. The wall thickness d'es Eohrprqfils that comes out of the extrusion head 3 thus changes with the Width of the gap 13. ·

A curved cooling jacket is attached to the nozzle 8 on the flanges 14 15 attached ,, which is held by its flanges 16 and fastening elements (not shown) on the flanges 14 is »The cooling jacket 15 cools through the extrusion head 3 exiting liquid thermoplastic extrusion mass / from and gives the pipe bend the desired geometric shape Shape. In the drawing, the cooling jacket 15 is with double walls 17 and 18 ', between which the entering through an inlet nozzle 19 and through one Drainage pipe from flowing cooling water circulates.

In the direction of movement of the emerging from the cooling jacket .15 A pulling device 21 is arranged in the tube and consists of a pulling chain 22, a pulling wheel 23 and further pulling wheels 24.

Fig. 2 shows schematically the pulling device 21 and the drive device for the pulling wheels 23 and 24. The drive device consists of a motor 25 with variator, which drives the chain 22 via a shaft 26 with a drive wheel 27, which in turn drives the pulling wheels 23 and 24 Sprockets 23 ^r and 24 'and shafts 23 ■ "and 24" drives.

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The thermoplastic extrusion material, for example, HD (high density) - may be polyethylene, is "inserted into the cylinder 2 as zähe.Masse at a temperature of about 200 ⁰ C, the rotating Strangp.re ßschraube 1 presses the mass through the perforated disc 2 'in the extrusion head 3. From there, the mass passes the holding arms 5 into the gap 13 between the mandrel 4 and the nozzle 8, so that the extruded material has a tubular shape when it enters the curved cooling jacket 15, the gives the resulting drill the desired curvature. During the creation

inside the ear there is an overpressure of 0.5 ρ

up to 0.6 kp / cm available, which by means of, the channel 6 supplied air is generated. In order to keep the Eohr tight during the extrusion process, is on its front A plug inserted at the end.

The finished extruded curved ear can be used during of the extrusion into finished drilling arcs at desired angles, for example 45 or 90, are cut. If necessary, the ear can be bent so that you get turns that are next to each other and one Forming a helix «, when cutting off the thread, that becomes The ear is first clamped airtight, so that the excess pressure inside the ear is not lost due to the cutting, After cutting, the plug is reattached to the anterior end of the exiting ear during the ear is still clamped together. If necessary, the plug can also be pushed into the ear before being cut off the drill bit lying outside the plug must be cut off.

ITm to give the Eohrbogen an even wall thickness, the mandrel 4 · and the nozzle 8 must be adjusted eccentrically to one another, so that the annular nozzle opening 13 has the largest gap width at the point where the larger amount of material is required for the drill to be extruded will. The eccentricity of the mandrel 4- with respect to the nozzle 8 can be calculated in advance, but must be in

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the practice depending on the present manufacture conditions must be set precisely afterwards «, at large wall thicknesses or high production speeds can be an additional. Cooling through the cooling jacket created cooling turn out to be necessary, which e.g. by means of a water shower between the cooling jacket and the pulling device. 21 can be effected «," ■.

During extrusion, that part of the surface of the pipe bend on which the pulling wheels 24 engage is always moves at a greater speed than the one Part on which the pull wheel 23 rests. To for the Pulling wheels ensure a peripheral speed that corresponds to the radius of curvature of the surface line of the Eohrbogen, on 'the the respective Eohr rests, is adapted, a correspondingly larger diameter is for the pulling wheels than for the Pull wheel 23, as shown in FIG. 1, is selected. It there is also the possibility; pulling wheels of the same size use and this through the interposition of transmission gears between the drive motor and the wheels to give different speeds of rotation.

When the pulling wheels 23 and 24 on those surface lines of the pipe flange that have the smallest or (largest Have a radius of curvature, the ratio \ der..circumferential speed en of the pulling wheels by the ratio (Em + o, 5 D) / (Em - o, 5D), where Em is the radius of the arc to the center line and D is the diameter of the ear arch. .. "■".

Claims

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Claims (4)

- α - Claims M.) Process for the production of pipe bends from thermoplastic Plastic with an essentially constant wall thickness and with one in relation to the radius of curvature of the pipe bend large pipe diameter, characterized in that in one Pipe extrusion head, the mandrel and nozzle of which are eccentric in relation to one another in a manner known per se, a tube with different wall thicknesses, but with a uniform pattern around the nozzle opening of the extrusion head is extruded around distributed outlet speed and that the tube is directly in a cooling jacket with the desired constant curvature is introduced, with that jacket area of the pipe that is in the nozzle opening has the greatest wall thickness, receives the largest radius of curvature in the cooling jacket, so that a pipe bend in the cooling jacket is formed with the desired curvature and essentially constant wall thickness « 2. The method according to claim 1, characterized in that the curved pipe emerging from the cooling jacket is pulled out by a pulling device with pulling wheels, whose peripheral speed corresponds to the radius of curvature of the surface line of the tube on which the respective wheel rests, is adapted. 3- The method according to claim 1 or 2, characterized in that that the curved pipe emerging from the cooling jacket in a direction perpendicular to the plane of curvature is bent so that a continuous helical tube is extruded into desired Angular distances to finished pipe bends is separated. 4. Device for performing the method according to one of claims 1 to 3 with a pipe extrusion head, 409824 / 1003- whose well and whose nozzle 'can be adjusted eccentrically in relation to one another, characterized in that that a curved cooling jacket (15) the extrusion head (3) adapted and the cooling jacket (15) a pulling device (21) is assigned for curved tubes. 5. Device according to claim 4, characterized in that that the pulling device (21) contains pulling wheels (23, 24) whose TJmf angspeedaadeii bending radii and! diameters of the curved pipe can be adjusted. 409824 / 10Q3 Blank page