JPS608876B2 - A device that continuously forms a plastic coating layer on a longitudinal body. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a heating means for heating a hollow body or other elongated body, a coating means for supplying plastic powder to the elongated body, and a coating means for heating the coated elongated body. The present invention relates to an apparatus for continuously forming a plastic coating on hollow or other elongate bodies, such as conduits, each provided with cooling means for cooling the body.

The coating of hollow bodies, especially conduits, with plastics has become widespread in recent years.

For this purpose, coating methods are increasingly being used in which the melting of the powder is carried out in two stages. In this method, a predetermined amount of plastic is melted on the metal surface of a conduit that has been preheated to a predetermined temperature, and this conduit is reheated in a subsequent process step, thereby completely melting the molten powder. A smooth covering layer of plastic is formed. A device for carrying out such a method is described in Austrian Patent No. 342,738. The device is equipped with an induction coil so that the continuous conduit to be coated is heated to the surface temperature necessary to melt the plastic. The heated conduit is guided through the coating head and is brought into contact with a turbulent mixture of plastic powder and air inside the coating head. The continuous conduit with the molten plastic powder coating is then passed through a second induction coil and is sufficiently heated by the second induction coil to form the molten plastic powder coating. is completely and uniformly dissolved. The coated conduit is cooled in a water bath, as described below, and is removed from the apparatus after passing through suitable cutting or winding means. The remainder of the plastic powder flowing through the coating head described above is separated from the air stream in a cyclone. On the other hand, in the case of thick-walled conduits, the molten plastic coating layer can be heated by the first induction coil to a high temperature at which it completely melts, so that no further auxiliary heating is necessary when the conduit exits the coating head. . It will be appreciated that the plastic powder is fed into a heated hollow body and is blown onto this hollow body in an electrostatic field.

Such devices have the disadvantage that coating can only be carried out at relatively moderate speeds. For this reason, German Patent Application No. 2616
No. 292 teaches providing a traction means following the cooling device and comprising two rotating belts,
The rotating belt engages the top and bottom of the conduit and serves to pull the conduit a predetermined distance and at a predetermined speed without damaging the plastic coating. If the traction force exceeds the limit, the rotating belt for traction begins to slip relative to the conduit to be towed, which disadvantageously limits the speed at which this conduit can be towed by the above-mentioned traction means. .

The method described above also has the disadvantage that the traction means can only move conduits with a circular cross section.

It is an object of the invention to coat hollow bodies with a cross-section different from circular at high speed through the coating means of the above-mentioned formation with a plastic coating which is respectively uniform in thickness, uniformity and strong adhesion to the elongated body. It is possible to move the layer without adversely affecting the formation of the layer.

If necessary, it is also possible to carry out a final shaping of the coated elongate. This objective is achieved by using traction means that can be used to shape or deform elongated bodies such as wires or conduits. The traction means comprises at least two traction slides pivoted by a shaft having at least two cam means and having a clamping member. In order to transfer the elongated body from one slider to another, the control means controls these sliders so that these sliders move an appropriate distance while respectively engaged with the elongated body. It looks like this. Further, the slider is configured to disengage from the elongated body during its return movement. By means of the two slides that alternately engage the elongate body, this elongate body is pulled reliably and continuously.

As a result, the elongate body continues to move during alternating connections with the elongate body between the traction slides, and the coating operation is not adversely affected by vibrations or shocks.
Preferably, the towing clamping member is configured to be replaceable so that elongated bodies having different cross sections can be towed.

The elongated bodies of different cross-sections can be towed with one edge located downwards in order to prevent water droplets from the cooling means from running down and forming streaks in the plastic covering layer. The traction force exerted by the traction means used in the present invention is determined by the
The traction force of No. 292 is 10 times greater than that of the traction means. For this reason, the elongate body to be coated can be moved over larger spans. This is especially important when the operation is required to be carried out at very high speeds, especially in powder melting processes where sufficient time should be allowed for cooling the elongate. By using such a traction slide, it is possible to modify the shape of the coated hollow body, in particular its cross section, since a drawing die can be attached to the tip of the traction slide. Next, one embodiment of the present invention will be described based on the accompanying drawings.

An endless or very long conduit 1 with a diameter of 12 ribs and a wall thickness of 1 willow is manufactured by forming and welding endless or very long strips, first of all by chemical or mechanical treatment. After the preliminary treatment has been carried out at 2 in FIG. 1, the solvent is subsequently removed from the conduit 1 in a drying chamber 3.

Thereafter, the endless conduit 1 to be coated is
It is preheated in the induction coil 4 to a temperature of over 18,600 degrees Celsius, which is necessary to melt the plastic to be coated on top. The heated conduit 1 is transferred to a coating head 5, inside which it is contacted with a mixture of plastic powder and air. The flow rate of the mixture at this time was 45/sec.
．． and the mixture has a density of 1.5k9, for example.
Contains polyamide 11 powder having a particle size of 20 to 80 microns. A continuous conduit 1 coated with molten plastic to a thickness of 140 microns passes through the coating unit via an outlet 6 and is coated with polyamide-11 by a second induction coil 7.
is heated again to a temperature above the melting point of , thereby completely and uniformly melting the molten plastic coating layer. The coated continuous conduit 1 is cooled by a subsequent water bath 8 and then fed by a traction mechanism 16 to suitable cutting or winding means. The continuous conduit 1 is about 110 units' min. move within this device at a speed of In the coating head 5 of the device there is a flow of a mixture of plastic powder and air. That is, the powdered plastic is fluidized by raising air to form a fluidized bed, which is then led to the coating head 5 via an annular nozzle. Air from the outside is drawn in through the outlet 6 to increase the velocity of the plastic powder introduced into the coating head 5 and to spread it evenly. Passing through the coating head 5, the plastic powder is separated in a cyclone 9 from an air stream which is sucked in via a filter 10 by a blower 11. The plastic powder separated in cyclone 9 is recycled from this cyclone 9 via valve 12 to fluidized bed 15. Replenishment plastic powder from the powder dissolver 13 is intermittently supplied to the fluidized bed 15 via a valve 14, thereby replacing the consumed plastic powder. The traction mechanism 16 includes a plurality of, for example two, traction sliders 17 and 18, which move back and forth along the direction of movement of the conduit 1. These sliders 17, 18 operate alternately. That is, while the slider 7 is engaged with the conduit 1 and is moving the conduit 1 in the direction of movement, the slider 8 is disengaged from the conduit 1 and engages with the conduit 1 to move it in a predetermined direction. The slider 17 is moved in the opposite direction to prepare for movement in the moving direction. These sliders 17 and 18 are provided with sandwich members 31 and 32, respectively, shown in FIG. Further, as shown in FIG. 3, the sliders 7 and 18 are configured to engage with cams 24 and 25 and move in response to these cams 24 and 25, respectively. It is mounted on cam drums 22, 23 which can rotate together. Note that the shaft 21
The rotation is performed by a motor (not shown). Furthermore, these sliders 7 and 18 are connected to guide rails 19 and 20.
1 will guide you. Each cam 24,
25 is interposed between two rollers 26, 27 for the cam and two rollers 28, 29 for the cam 25, respectively. each installed.

Since the force rams 24, 25 are arranged in relation to each other in such a way that their operating cycles complement each other, the sliders 17, 18 can perform an oscillating movement, i.e. a reciprocating movement, thereby allowing an endless The conduit 1 moves in a predetermined direction of movement (
(in the direction from the left to the right in FIG. 1). While one slider engages the conduit,
The other slider returns to the return position. FIG. 4 is an enlarged view of the slider with the cover plate removed;
According to the embodiment of the invention using the traction clamp shown in the figures, the conduit 1 is engaged by a slider 7 or 18.

The slides 17, 18 are provided with clamping members 31, 32 for towing the conduit 1, which clamping members 31, 32 are connected to movably constructed inner slide bars 35, 36. Furthermore, rollers 33 and 34 are arranged in a line between the inner slide rods 35 and 36 and the immovable outer slide rods 37 and 38. The clamping members 31, 32 are energized by a gas cylinder, for example an air cylinder, which is arranged on the cover plate and whose piston rod is connected to the inner sliding rods 35, 36, and these clamping members are arranged in an inclined position. It moves along the rollers 33 and 34 that are present. In FIG. 4, as the clamping members 31, 32 move from the right to the left, they gradually close and engage the conduit 1 held within them.

This movement occurs due to a series of rollers 33, 34.
This is because they are each arranged in an inclined and tapered state. When the slide rods 35, 36 are moved by the air cylinder in the opposite direction (ie from the left to the right in FIG. 4), the clamping members 31, 32 are disengaged from the conduit 1. The mechanical device can also automate the operation of the air cylinder by using an electromechanical device, or alternatively, the actuation of the air cylinder by an operator's actuation of the engagement of the clamping member. Semi-automation is possible.

The operating cycle of sliders 17, 18 is shown in FIG.

The slider 7 moves at a speed v along the path from point A to point B.
, while towing the conduit 1, the slider 8 moves the conduit 1 from point G to point H or slightly before it (from point G to point H is equal to the distance from point A to point B'). is towed at speed v to point H. At point H or a little before it, the closed clamping part village 3 of the slider 18
1 and 32 move to release the engagement with the conduit 1, and the slider 18 moves back along the path from point H to point E at the speedometer 2 (note v, v2).

During this time, the slider 17 pulls the conduit 1 along the path from point B to point C at a speed v. While the slider 17 tows the conduit 1 along the path from point C to point D or a little before it and moves to point D, the clamping members 31 and 32 of the slider 8 close, and the conduit 1 moves to point E or just before it. It is towed at a speed v along a pilgrimage from slightly behind to point F (the distance from point E to point F is equal to the distance from point C to point D). At or slightly before point D, slider 17
The engagement between the closed clamping members 31 and 32 and the conduit 1 is released, and the slider 7 moves back along the path from point D to point A at the speedometer 2 (where v, <v2). During this time, the slider 8 moves the conduit 30 along the path from point F to point G at a speed v. Tow with. The gist of the present invention can be summarized as follows in accordance with the above embodiments.

The device according to the invention comprises heating means for heating a hollow or other elongate body, coating means for supplying plastic powder to this elongate body and cooling means for cooling this coated elongate body. An improved apparatus for continuously forming a plastic coating layer on an elongate body, each comprising a cooling means for forming a plastic coating on an elongated body.

The apparatus is provided with traction means that can be used to form or deform continuous elongated bodies such as wires or conduits. The traction means has at least two traction slides driven by a shaft having at least two cam means, each of which is provided with a traction clamp. control means are provided for controlling the sliders so that the sliders move a suitable distance while respectively engaged with the elongated bodies in order to transfer the elongated bodies from one slider to another; The slider disengages from the elongated body during its return movement.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a schematic side view of the entire device, Fig. 2 is an enlarged schematic plan view of the traction mechanism shown in Fig. 1, and Fig. 3 is the same as Fig. 1. FIG. 4 is a cross-sectional view of the traction slider shown in FIGS. 2 and 3, and FIG. 5 is a schematic side view of the main parts of the traction mechanism shown in FIG. FIG. 4 is an end view of the traction holding member, and FIG. 6 is an explanatory diagram showing the operation cycle of a pair of traction sliders. In addition, in the symbols used in the drawings, 1...
- Conduit, 4... Induction coil, 7... Second induction coil, 16... Traction mechanism, 17,
18... Towing slider, 22, 23... Cam drum. Fig. 1 Fig. 2 Fig. 3 Leopard Fig. 4 Fig. 5 *6 Fig.

Claims (1)

[Scope of Claims] 1. A heating means for heating a longitudinal body, a coating means for supplying plastic powder to the longitudinal body, and a cooling means for cooling the coated longitudinal body. a traction means associated with said elongate body and having at least two traction slides; and at least two cams. said slider being driven by a shaft having means and having a clamping member, and a suitable means for transferring said elongate body from one slider to another, with said sliders respectively engaged with said elongate body; and a control means for controlling these sliders so that they move a distance of a distance, and the slider disengages from the elongated body when the slider moves back. . 2. The device according to claim 1, wherein the elongated body is a thin hollow body. 3. The apparatus according to claim 1 or 2, wherein the heating means is controlled by a temperature control means. 4. Any one of claims 1 to 3, wherein the cam means is comprised of a cam drum.
Equipment described in. 5. The device according to any one of claims 1 to 3, wherein the appropriate distance is a short distance. 6. The device according to claim 4, characterized in that two traction sliders having clamping members are provided and two cam drums are provided. 7. The heating means is provided upstream of the coating means,
7. Claims 1-6, characterized in that the elongated body is heated by said heating means before being supplied with plastic powder by said coating means. Equipment described. 8. Auxiliary heating means are arranged between the coating means and the cooling means in order to heat the plastic powder supplied to the elongated body by the coating means to form a smooth coating layer of plastic. An apparatus according to claim 7, characterized in that: 9. The device according to any one of claims 1 to 8, wherein the holding member is replaceably attached to the slider.