DE1652447A1 - Method and device for the internal coating of elongated hollow objects, in particular pipes, with thermoplastics - Google Patents

Description

to: German Patent Office Munich ID b 2. 4 4 7

January 18, 1968

Method and device for the internal coating of elongated hollow objects, especially pipes, with thermoplastics

The invention relates to a method and a device for

Inrien coating - of elongated hollow objects', ins- \

special pipes, with thermoplastics that are used in Powder form can be applied to the objects.

Several processes have been developed and made known to apply plastic protective layers to the inner and outer jacket surfaces of pipes and similar elongated objects further trained (DBP-1 172 165). This method consists in that the plastic powder is mixed in a storage vessel with air and is fed with the help of excess pressure by the ~ to be coated * the objects. Where the objects are heated to above the melting temperature of the granulate, its wall adhesion is produced as a "be ^: favorable ± ^: gt ^ / ünd ^ in" an open-ended coating.

The disadvantages of this method are the uncontrollability of the uniform application (layer thickness) and, on the other hand, the fact that a lot of excess powder has to be removed from the objects. Separators and / or filters must be used for recovery. With the electrostatic application process, only small layer thicknesses could be achieved so far , since the first applied layer has an electrically insulating effect and further powder no longer adheres.

on the other hand, the method according to the invention consists in _B

to: German Patent Office Munich 16524 A 7

18.1 ο 1968

that the fluidized in a known manner, plastic powder progressively from one time to the other end of the Äohres and locally by AEM also locally -fortsdireitenden applying an adhesion promoter is applied, wherein the application of both the 2Cunst materials in powder form s (Pluidats) and the ^adhesive: promoter takes place under the influence of an electrostatic field generated in a known manner between their radially acting distribution member (s) on the one hand and the pipe to be coated on the other hand.

The new method has several advantages over the previously known method. As a starting material for coating can e.g. B-. the liquid produced by the fluidized bed sintering process Jaer Adhesion promoters and powdered ThenaoiuLaste can be used. After electrostatic coating, the deposited becomes thermoplastic Powder (in a known manner) by induction coils, ring burners or other energy sources above its melting point heated and sintered to form a closed coating. .

The inventive method is v / ird in the following with reference to the drawing, in which an exemplary embodiment of a device suitable for carrying out the method is described, explained in more detail. This device is! Part of the invention «

In a stock sbeh ..;.! The granulate is mixed with air via (1) the resulting fluidate is pneumatically conveyed through the line (2) to the device (3), which is a slide made of several individual parts, which corresponds to the internal dimensions of the objects to be coated (in Pig . 1 a tube (4) -) is adapted.- The construction of this slide is "described" further below electrically isolate against the wall. At the end of the slide, which carries the pneumatic conveying line centrally, there is a distribution element (5) for the uniform spreading of the fluid. The electrostatic Felö _s between the carriage (3)

1.099-1270452 _ ₅ _

⁰ ^ QlNAL

to: German Patent Office Hüiiohen I O ü Z 4 4 · /

January 18, 1968

with V.erv.iiler ib) and Äohrwandung (4) is generated by a source of tension (o), advertises that it can be used in conjunction with a suitable shape of the fluidate. AND ALL required -.ulver reaches the Hohrwariaung and _c z.ut liable ,, order to produce 'a gleichmäßii-.en layer thickness of the slide is continuously driven through the tube. Excess: do not remove the powder afterwards, because it is not present. · · '-.' ·. ■

üine two distributing device (7). "is located at a gev / iFsem distance - in Yorsc-.ubriclitung - in front of the-i ilunststo-jiivistributor (p) and .alent to apply a primer. Dasu leads another pumping line (8) from a storage container (9) in parallel to the line (2) on Y Teilvorrichtmig (1). The distribution also happens in the electrical Pe-Id .. primer and granules can be applied one after the other in a Arbeitsjang “The, only short period of time between the processings sufficient to dry the primer due to the special (electrostatic) application method.

With a special Eaftgrund, the charge dissipation (to the Eohr) be improved; this makes it possible to apply thicker layers »It is, under certain circumstances, even an advantage if the adhesive is still damp when the powder is applied, since then · the charge dissipation is better.

]) as powder is already so good that sintering on expensive heat sources, such as. B. Induction coils can be dispensed with and circulating air or indirect radiation drying can be used »

The process of applying conductive primer prior to electrostatic coating with powder can also be used for external coating of objects. The primer is then z «B eingeblaeen ₀ over Hochdruckzerstäuber as an aerosol in the electrostatic field between the object and DVSE.

10 9 812/0 452

BATH

to: German Patent Office Munich 165 2447

18.1 ο 1968

The "carriage" mentioned above consists primarily of several support brackets (11, 12 ...) provided with running wheels (Fig. 2). Either the impellers themselves are made of non-conductive material manufactured and / or there are support legs (31 ...) used, which the should opposite the conveyor pipe and its carrier (41, 42 ..) isolate.

In one embodiment of the invention, a rigid conveyor pipe (2) is rotatably mounted in ball bearings (41) sui the Trä, gerböcken (11, 12 ...) Distribution cover (5) is connected in the bearings (41 <> ..). The motor for the uniform spreading of the culvers lying on the el _o potential of the carriage or is floating. The distributor bell (5) is closed off by an Irallteller (5a) (Figure 3), so that the parts (5) and (5a) form an annular discharge gap. The baffle plate (5a) prevents powder from being blown in an uncontrolled manner from the conveying line (2) into the object (4) to be coated. It can be made of insulating material so that the electric field is not influenced. the discharge gap perpendicular to the axis »However, the discharge plane formed by the ring splint can also form any angle with the axis =

Get the best results in terms of even application you when the Yteilglocke rotates centrally in the pipe with an even distance from the wall. That can be achieved by using appropriate slides for different pipe widths will. But you can also make the length of the carrier basin (11 ...) in the support (31 ...) adjustable and so for different pipe widths center the axis of rotation (2).

1098 12/0452 -5-

SAD ORIGINAL

to: German Patent Office, Munich '. 165 2447

* / 77

180101968

A second delivery line (8) can be rigidly attached to the trestles (11) mounted parallel to the conveying line (2) from a storage vessel (9) to a further distributor (7) which - in feed direction seen of the slide - lies in front of the distributor (5). The distributor (7) rotates on the axis (2) and distributes the adhesive conveyed in the line (8) after same principle as the distributor (5); In contrast to the device (5), the distribution plate (7) is operated by spraying from the delivery line (8) and is not in coherent connection with this., In a further 'design the invention it is proposed that the slide (3) from each other movable individual members (11 ..,) with joints (51 to manufacture, or to use flexible shafts and so the device can also be used for coating eg elbows

It is also possible to use an electric motor drive to waive the distribution devices by using parts thereof as Drive motor can be designed with guide vanes. This can then be driven by the fluid itself or by compressed air.

The support brackets (11 ...-.) ■ then only serve to support the delivery lines bewz. Pressure lines - which can then be flexible - to be kept away from the walls of the objects to be coated »

-Patent claims-

TQ9812 / 0452 bad original

Claims (1)

to: / Deutsches, r at ent amt Munich 16 52447 January 18, 1968 t e η t an s ρ return 1. Process for the internal coating of elongated hollow Objects, especially pipes, with thermoplastic Plastics that are in powder form on the objects on ^ e- ^ be brought, d a d ure h g e k e η η ze i c h η e t, that the plastic powder fluidized in a known manner progressively from one end to the other end of the drill is applied temporally and locally after the likewise locally progressing application of an adhesion promoter, wherein the application of both the plastic powder (pluidate) as also the adhesion promoter under the influence of an intermediate whose radially acting "distributor (s) on the one hand and the one to be coated tube on the other hand existing, in a known manner generated electrostatic field takes place. Device for carrying out the method according to claim 1, consisting of a container for receiving the plastic powder, in which the powder is whirled up by an air stream and a fluid is produced, a pneumatic conveying line (2) for transporting the fluid, a further conveying line (8) for Transport of an adhesion promoter and one or one distribution member for the adhesion promoter (7) and the fluidate (5), thereby geke η η ζ calibrated η et that the distribution member or members (5,7) are parts of a slide (3) ^ , which is electrically insulated from the pipe (3) to be coated can be moved into it on rollers (21, 22 ...), the pipe being connected to one pole of a high- voltage source M ₀ , the carriage or the distributing members to the other pole -. "- .; ■ 109812/0452 German Patent Office Ilünchen 1652447 18.1 ο 1963 5-. Distributor for the device according to claim. 2, thereby marked that parts of the slide, mainly the axis concentric to the head, in fixed bearings of the slide are rotatable. 4. Device according to claims 2 and 3, characterized characterized that the (rotatable) centri- ' see axis is designed as a hollow axis and as a delivery line serves for the i'hermojjlastjjulver. ^. Device according to claims 2 to 4, characterized g e Ic e η η ζ e i c h η e t that is attached to the hollow axle a distributor bell connects, which in a.n known manner with the axis or also alone in the bearings mentioned (4. ·.) Rotates and that a rallteller (primarily from non-conductive material) the distribution cover perpendicular to the iörderrichtung closes, which forms a discharge ring gap with the distributor bell. b. Device according to claims 2 to 5, characterized geke η η ζ calibrated η et that a similar distribution organ εη for an adhesion promoter at a sufficient distance from * i'powder distributor on the same axis as and with this one. * is rotatably mounted, the .laftvermittler mittis a rigid delivery line (8) is fed from the side. 7. Device according to claims 2 to 6, characterized characterized in that one or both distribution bells are attached obliquely to the axis of the conveyor pipe (2). Device according to claims 2 to ^ T-f thereby marked, d_a = ß said carriage made up of several mutually movable in Eardan joints (51 ...) There is a link with a hollow axle that is rotatable as a whole, or that the central axle of the slide is a flexible hollow shaft. 10 9 81 2/0 4 5 2 -8- ;.% t BAD German Patent Office, Munich : hilde January 18, 1968 9. Device according to claims 2 IdIs 8, characterized characterized in that parts of the distribution devices designed as drive rotors with guide vanes are generated either by the energy of the fluidate or by Compressed air can be driven from an auxiliary line. 10, device according to claims 2 to 9 »thereby g e k e η η ζ e i c h η e t that a pneumatic or electrical device automatically and "evenly move the carriage." drives through the pipe and that possibly at the same time in an induction coil or a ring burner at a defined distance etc. is carried on the outside of the pipe for sintering » 109812/0452 Empty soap