DE1192396B - Method and device for the continuous production of plastic pipes reinforced with fibers - Google Patents

Description

Method and device for the continuous production of with Fiber-reinforced plastic pipes The invention relates to a method and a Device for the production of seamless pipes from thermosetting plastics in any dimensions.

It is quite a process for the continuous production of with Fibers reinforced plastic pipes became known, in which a hardenable plastic and fibrous reinforcement material on an extrusion core be applied, which is moved in the axial direction and from a low-melting point Material consists, which melted out after solidification of the plastic pipe will. In the previously known method, the tubes are before the melting of the metallic The core is divided into pieces of the desired length, followed by the metallic Core is melted out of each of the pieces. Precisely this process step, in which the individual sections of the plastic pipe are individually melted must be subjected, causes a considerable increase in the cost of the previously known Method, since he, if at all, only with extremely complex devices can be performed automatically.

The invention is now based on the object of creating a method with its help, ready-to-install plastic pipes are produced fully automatically can be.

This task is according to a method of the known type the invention achieved in that the core produced as a tube, the melting continuously made and the melted core material through the interior of the still solid core is discharged. In this way, the advantage is achieved that the core of the continuously produced plastic pipe before it is divided can be melted continuously, so that following the melting Manufactured sections of the plastic pipe no longer require any further treatment.

The removal of the molten core material is particularly simple made in that the core moves vertically upwards and that through the core melted material flowing back from the extruder for the renewed formation of the Kernes is fed back. This eliminates the need for special devices for Discharge of the molten core material and it becomes more continuous at the same time Cycle guaranteed.

The method according to the invention therefore allows a particularly time- and cost-saving production of seamless plastic pipes.

To make the return of the molten core material particularly easy To design a device for carrying out the process can be an extrusion press Od. Like. For the production of the core and an induction heater for continuous Has melting out of the core, so in an advantageous development of the invention be designed so that the nozzle core of the extruder is tubular.

In the manufacture of plastic pipes from using a thermosetting Reinforcement sheets soaked in plastic, it was customary to use the od on spools. Like. Wrapped reinforcement webs around the core. However, this is disadvantageous insofar as devices in which these coils together with their holders able to rotate the core, relatively complex in their construction are. To avoid this disadvantage it is therefore proposed according to the invention, to arrange the core rotatably about its longitudinal axis together with the extruder. the Coils or conveying devices for the reinforcement webs can with such a Device can be arranged stationary.

The melting point for the preferably eutectic metal alloy for the production of the core is expediently chosen so that it is between the Curing temperature and the highest allowable temperature for the cured Resin lies.

In the drawings are exemplary embodiments of the invention Devices shown in a schematic manner. 1 shows an exemplary embodiment the device according to the invention in section, Figure 2 shows another embodiment in section, FIG. 3 a hardening furnace, as it is for the devices according to FIG. 1 and 2 is used, and FIG. 4 shows an overall view of the system according to the invention.

The device for the continuous production of a metal pipe 10 consists of a hollow cylindrical spray nozzle and a pressure pump 17, which is coupled to an electric motor 20 and arranged within a crucible 14 is. This crucible is arranged below the spray nozzle 11 and contains the liquid Alloy 15, which with the help of a thermostatically controlled heating element 16, the is also arranged in the crucible 14, is liquefied. All of these parts are housed in a cylindrical housing9, which is arranged on a perpendicular Hollow shaft21 is mounted. The hollow shaft 21 is in the two bearings 22, which are both absorb radial and axial forces, stored.

About a drive unit not shown in the drawings can the whole device rotated in a known manner at the desired speed will. In this case, the power supply for the motor 20 and the heating element 16 takes place in a known manner via the sliding contacts 23. By a remote-controlled speed control The two motors can continuously manufacture the one from a fusible Alloy existing pipe, its upward movement and at the same time also its Rotational speed can be regulated and adapted to the respective requirements.

Above the spray nozzle equipped with a cooling device 13 11, the mouthpiece of which is denoted by 12, is the tape impregnated with synthetic resin or the fiber strand made of glass fiber 25 is applied. As a result of the axial feed and the rotation of the metal tube 10, the tape or strand is wound onto it, where the thickness of the applied layer depends on the speed of rotation, the Feed speed and also on the thickness and number of layers of the tape or Strand is dependent. In this way, 10 is applied to the metal tube serving as the core applied a fiberglass reinforced synthetic resin layer 24, which then must be hardened.

In the case of the use of fiber strands, provision can also be made that the material feed a controlled oscillation movement in the vertical direction executes, whereby the strands can be applied in crossed layers. Through this an increase in tensile strength in the longitudinal direction of the synthetic resin pipes is achieved.

It is possible to use the synthetic resin and the fiberglass one after the other, known methods, such as. B. to apply by spraying, rolling or pressing, glass fiber can be added to the synthetic resin in crushed form.

In contrast to the arrangement according to FIG. 1 are parts 11, 14, 17 and 20 in the embodiment according to FIG. 2 fixed. Here too, the metal pipe is used 10 cast upright. Above the spray nozzle 11 there is an additional nozzle 26, which via a supply pipe 28 with a mixture 27 of plastic resin and crushed Fiberglass is loaded.

As the metal tube 10 moves in the direction of the arrow, it will open a layer 29 of fiberglass and synthetic resin is applied to him through the nozzle 26.

The process by which the tube used as the core is produced in the continuous Casting process is established and evenly melted again, with tapes or strands of synthetic resin-soaked glass fiber is wound, can also be carried out in this way that the material feed moves around the stationary pipe.

The device according to FIG. 3, both with the fixtures according to Fig.1 and Fig.2 can be combined, is arranged above the point on which the task of the synthetic resin-soaked fiberglass takes place. A cylindrical one Hardening furnace or tunnel 30 concentrically encloses the metal pipe 10 with the one on it applied layer of synthetic resin soaked fiberglass. This curing oven can be electric be heated, the temperature required to harden the resin through an automatic control device is kept constant. The length of the curing oven 30 is determined by the feed speed and is designed so that the Tube remains inside the hardening furnace until the hardening process is complete.

An electric induction furnace 31 is arranged above the hardening furnace, in such a way that the tube coated with synthetic resin-soaked fiberglass from the active zone of the induction furnace is enclosed. By the induced electrical Eddy currents melt the metal pipe 10 as it passes through the induction furnace and drips through the still solid lower part of the metal tube 10 and the hollow Spray nozzle 11 into crucible 14.

This is how the finished and cured synthetic resin pipe comes out 24 continuously out of the induction furnace 31 and is from the metal pipe 10, which still served as a core in its soft state, completely freed.

A complete, automatically operating system for manufacturing glass fiber reinforced synthetic resin pipe is mounted on a base 33 as shown in Fig. 4, which carries an upright frame 34 with the upper cross members 35. On the Base 33 is a casing 36 mounted in which the bearings for the hollow main shaft 21 and the gearbox of the machine are housed. By means of this gear, the can be designed for different, adjustable speeds, the Main shaft offset in rotation. A switch box 38 is located above the housing 36 arranged in which the slip rings and sliding contacts of the power supply and for the control pulses described below. Located in the control box38 There are also the stuffing boxes for the supply of the coolant with which the spray nozzle 11 is cooled. The electrical supply lines and the supply line for the coolant run through the hollow main shaft 21. On the main shaft 21 is also located a housing 19 for the motor 20 (FIG. 1), the speed of which can be regulated. This motor drives a gear pump 17 (FIG. 1), which is located in a crucible 14 in which the metal is melted. The crucible is also with a thermostatically controlled heating element and is, as described above, with molten metal one easily Fusible alloy filled. The pump 17 (FIG. 1) supplies the pressure required at the spray nozzle 11. In this Spray nozzle, the metal is cooled and occurs, as described above, as a metal tube from the top of the nozzle.

Immediately above the spray nozzle there are two immersion vessels 39, through which the fiberglass strands between rollers into a bath of liquid synthetic resin be guided so that the roving fibers are impregnated with synthetic resin while At the same time, the air is squeezed out of the web and excess synthetic resin is wiped off will. The ribbons made of fiberglass web are made from the center of reel-less rolls 41 unwound, passed through the heating channels 40 and through openings in the left side walls the immersion device 39 passed through against the metal pipe 10.

Two mixers 42 ensure the alternating supply of activated Synthetic resin with additives of dye and other components.

One of the containers supplies the resin mixture while the other from the main tank 43 with liquid synthetic resin and with the other components the additional tank44 is filled. The activated resin is shown along the dashed line Lines on both belts of the diving devices 39 distributed.

Care must be taken that the temperature with which the fiberglass web is preheated in the heating channels 40, the critical temperature, in which the liquid bath of the synthetic resin in the dipping device 39 gels, not These diving devices 39 are interconnected by the piston rod 48 connected and with the help of the cylinder and the piston 47 perform a hydraulic controlled oscillatory movement, its frequency and amplitude by a control device (not shown in the drawing) can be influenced.

The synthetic resin-soaked ones emerging from the dipping devices 39 Fiberglass webs are made by the rotation and the simultaneous advance of the Metal tube 10 wound on this, where it is due to the oscillating movement of the immersion device 39 so that the individual layers partially overlap and cover.

Here, the metal pipe 10 is impregnated with a mesh made of synthetic resin Glass fiber fabric covered.

By the movement of the diving devices 39, the strength and number the layers of fiberglass is also determined by the speed of the metal tube 10 and the amount of resin applied, the quality, strength and wall thickness of the synthetic resin pipes produced determined in a known manner.

The synthetic resin pipe 24 then passes through a nozzle designed as a nozzle Ring 46 with which a thin layer of synthetic resin is applied to the outer wall of the pipe which smoothes its surface.

It should also be mentioned that it is also possible to use a thermoplastic tape Material both in the application zone at 39 and above or below it Place to apply, whereby a fiberglass-reinforced synthetic resin pipe is made can be whose inner or outer wall made of a layer of thermoplastic material consists. This thermoplastic material can also be used as an intermediate layer in the wall be arranged of the pipe. Based on the experience gained in the manufacture of glass fiber stronger Plastic pipes were made, such a security layer can be in certain Cases prove beneficial.

The metal pipe passes together with the still uncured synthetic resin pipe then an electric induction furnace 31 '. By doing this in the metal pipe induced eddy currents, it is heated up to the melting point of the metal, wherein the synthetic resin layer of the applied plastic pipe 24 from the inside out is heated. Then the two RohrelO and 24 are through a heating tunnel 49, where the fiberglass-reinforced synthetic resin pipe continues to be heated by infrared radiation will. The amount of heat that the fiberglass-reinforced synthetic resin material in the heating channels40, the induction furnace 31 'and the infrared heating tunnel 49 must be taken into account the exothermic heat development of the synthetic resin can be adjusted so that the desired Hardening temperature is reached.

It should be noted that the hardening temperature is one of the most important Factors for the dimensioning of the curing time, as these are the case with such continuous manufacturing process is of paramount importance. When the fed If the amount of heat has been set correctly, the pipe will be completely cured and remains even after exiting the heat-insulated tunnel 30 and the infrared heating tunnel 49 hard.

After the two tubes 10 and 24 have passed the heat-insulated tunnel 30 have happened, they are led into another induction furnace 31, which Metal tube 10 heated so far by the development of eddy currents that it melts. The molten metal can then pass through a funnel that is placed inside the Metal tube 10 is arranged, and with webs or another device is attached to the inner ring of the spray nozzle. The funnel is connected to a heated pipe that leads into the crucible4 so that the molten Metal is fed back and, as mentioned above, switched back into the cycle will. (This arrangement cannot be seen from the drawing.) Now that of his Core-freed, fiberglass-reinforced plastic pipe is self-supporting and continues to rise upwards, with rollers that are arranged within a ring 50, is supported and centered. Above this ring is an automatic circular saw58 arranged, which participates in the axial feed movement of the finished synthetic resin pipe 24 '. With this circular saw, the finished plastic pipe can be cut to a predetermined length will. Before the resin pipe is cut, it will free itself from you detected rotating gripper 51 which is attached to an arm 52 of a carriage 53 and can move with the carriage on vertically arranged rails. The carriage 53 is via a chain 55, which is guided over a guide pulley56, with a counterweight 57 connected, the guide roller 56 being rotatably attached to the cross member 35 of the frame 34 is. With the help of this balance weight, the gripper exerts a pull on the plastic pipe 24 and pushes it to the side during the cutting process. The saw blade 58 is mounted on the shaft of a motor 59, which is also mounted on a carriage 60 in the The same rails run in which the carriage 53 also travels. As soon as the saw blade touches the finished plastic pipe24 ', it will as long as the cutting process takes along with the motor 59 and the carriage 60 by the pipe. the with respect to the pipe lateral feed movement of the saw blade can by a any automatic device can be triggered and controlled.

After the finished plastic pipe has been cut off, will it is moved to the side by the gripper 51. For this purpose, the arm52, the Gripper carries, composed of two articulated parts, one of which can be swung out (not shown in the drawings).

The finished plastic pipe is placed on a slide by the gripper 61 placed, from which it slides onto a transport means, preferably a conveyor belt62.

It goes without saying that the gripper 51 with the cutting device 58, 59 and 60 work together in a predetermined sequence and with the help of mechanical Devices can be returned to their original position.

All speeds, temperatures and others for the procedure important variable sizes can be done at a control panel63, which is located on the platform 64 is mounted, read and adjusted. In addition, the machine can be equipped with safety stop switches and / or warning systems to prevent malfunctions can be displayed during the work process.

The machine is designed in such a way that when passing from one Pipe diameter on another only the spray nozzles 11 and 46 and the pole pieces of induction furnaces 30 and 31 'need to be changed and some other settings must be done on control panel 64. For the changes regarding various For the quality of the plastic pipes of the same diameter, a few changed settings are sufficient at the control panel 64.

One machine for making 2 to 6 inch tubes and one capacity of about 2 m per minute has a total height of about 16 m and can depending on the Type of system operated by one or two workers. The annual output one such machine depends on the diameter and wall thickness of the plastic pipes dependent, but can easily reach 1000t and more per year.

Claims (4)

Claims: 1. Process for the continuous production of plastic pipes reinforced with fibers, in which a hardenable plastic and fibrous Reinforcing material is applied to a core produced by extrusion molding, which is moved in the axial direction, preferably upwards, and consists of a low-melting point Material consists, which melted out after solidification of the plastic pipe is, d a d u r c h g e - indicates that the core is manufactured as a tube, the melting continuously made and the melted core material through the interior of the still solid core is discharged. 2. The method according to claim 1, characterized in that the core moved vertically upwards and the molten material flowing back through the core is fed back to the extruder to re-form the core. 3. Apparatus for performing the method according to claim 1 or 2 with an extruder or the like for producing the core and an induction heating device for continuously melting out the core, characterized in that the nozzle core (11) the extruder for the purpose of returning the melted material to a Crucible (14) is tubular. 4. Apparatus according to claim 3, characterized in that the tubular Core is arranged rotatably about its longitudinal axis together with the extruder. Documents considered: French patent specification No. 1,096,597; U.S. Patent No. 2,829,699.