DE2424558A1 - DEVICE FOR APPLYING PROTECTIVE COATS ON METAL PIPES - Google Patents

Description

METALLGESELLSCHAFT 6 Ffm., May 17, 1974

Aktiengesellschaft - DrQ / GKp

6 Frankfurt (Main)
Reuterweg 14

Prov. No. 7370 LWK

Device for applying protective coatings on metal pipes

The invention relates to a device for two-stage Application, preferably by electrostatic spraying, flooding, airless spraying and curing, baking or melting a protective coating of a liquid or powder material onto the Outer surface of metal pipes, in particular iron and steel pipes, in one operation, consisting of continuous chain conveyors, on which the metal pipes lie horizontally and parallel to each other along a perpendicular are automatically transportable to their longitudinal axes running path.

According to patent. (Patent application P 23 28 403.9-45)

are two carrier chain conveyors, each provided with drivers, consisting of parallel chain strands arranged in line one behind the other, the distance between the chain strands is chosen so that the metal tubes rotatable about their longitudinal axis on one carrying chain conveyor with their end regions and on the one other chain conveyors with their with the applied and baked, cured or melted Protective coating provided areas rest, and that in the area of the conveyor line of the chain conveyor Spray booths for applying the protective coating and ovens

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for curing, stoving or melting through of the protective coating are arranged.

With this device, metal pipes in one. Operation with a uniform-looking, automatically applied protective coating with comparatively little effort be provided.

It has now been found that the possible uses of such a device can be significantly expanded, if, according to the invention, at least one further chain strand between the chain strands of the one carrying chain conveyor is arranged and the other carrying chain conveyor, whose conveyor line is with the conveyor line of the one Carrying chain conveyor overlaps, consists of at least two chain strands. This arrangement allows metal pipes of great length, but especially those of great length and small diameter, in a simple manner provided with a protective coating. The overlap of the conveyor line of one with the conveyor line of the other The carrying chain conveyor enables an uncomplicated transfer the metal pipes from one chain conveyor to the other.

The chain strands of one carrying chain conveyor are transverse to those of the other carrying chain conveyor Transport direction arranged offset in such a way that the one carrying chain conveyor with a protective cover ver seh enaa areas of the metal pipes after burning in, They harden or melt through lying on the chain strands of the other carrying chain conveyor »

In the context of the further embodiment of the invention, both the one and the other is between the chain strands

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other carrying chain conveyor as well as on the outside of the outer chain strands of the other carrying chain conveyor in each case a spray booth followed by an oven.

In the maintenance area of each spray booth there is a lifting device with which the metal pipes be lifted into the spray booth. For this purpose between the side walls of the spray booth and the Lifting beams attached to chain strands can be rotated around their axis transversely to the transport direction of the metal pipes Equipped with rollers that hold the metal pipes during the spraying process rotate around its longitudinal axis.

A modification of the device can be seen in the fact that the transverse to the transport direction in a row lying ovens are combined to form one oven, the chain strands being passed through the oven.

A further modification of the device according to the invention is that in the horizontal areas the Carrying chain conveyor replaced by walking beam continuous conveyor are. .

The device according to the invention is shown in the drawings shown schematically as an example and explained in more detail below:

In the device shown schematically as a side and plan view in Fig. 1 a and 1 b are on the the three chain strands 1 existing carrying chain conveyor from a magazine (not shown) with a protective cover to be provided iron pipes 2 abandoned and in their central area and in their end areas

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stored. The iron pipes 2 are under cyclical operation the spray booths 3 promoted and lifted by the lifting devices 4 from the carrying chain conveyor and into the Spray booths 3 used to apply the protective coating. Through the on the lifting beam of the lifting device 4 arranged transversely to the longitudinal axis of the tubes 2 rotating rollers 5, the iron tubes 2 about their longitudinal axis turned. Through the spray devices 6, the iron pipes 2 are exclusively their end and middle areas provided with a protective coating. After the protective coating has been applied, the lifting devices 4 lower the Iron pipes 2 back onto the chain strands 1 of the carrying chain conveyor. Then those in the fields between the middle and the end coated iron pipes 2 are transported to the ovens 7, in which the protective coating is burned in, thermally hardened or melted through. After leaving the ovens 7, the Iron pipes 2 through the two chain strands 8 of the other connecting chain conveyor from the one Carrying chain conveyor lifted off and in time under the spray booths 9 to apply a protective coating to the previously uncoated end and middle areas of the iron pipes 2 transported further by the lifting devices 10, the iron pipes 2 are then lifted into the spray booths 9, through which on the walking beam of the lifting devices 10 arranged rotating rollers rotated and provided by the spray devices 11 with a protective coating. After lowering the lifting equipment 10 and Vfiederaufgäbe on the chain strands 8 of the carrying chain conveyor the iron pipes 2 to the furnaces 12, in which the protective coating has hardened, are melted through or is burned in, transported further.

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1st embodiment

Medium-weight threaded pipes of 6 m length with an outer diameter of 60.3 mm, a wall thickness of 3> 91 mm and a pipe weight of 5.44 kg / running. m were given to the device according to the invention. The protective layer is applied with a “shop primer” based on epoxy resin, which has a flash point of over 21 ^° C. and a processing viscosity of 18 seconds in a 4 mm DIN cup. The protective layer was applied electrostatically with the so-called Ransburg bell at a voltage of 120 kV. Die.Taktzeit of the device was adjusted so that the tubes 2 remaining in the spray booths of the first carrying chain conveyor min and after 2 min flash-off time and a 5 min abandoned burn-in ovens at 200 ⁰ C to the second carrying chain conveyor. There, the pipes were coated for 2 minutes in the spray booths operating under the same conditions and after a flash-off time of 2 minutes and a baking time of 5 minutes in the ovens and a further 3 minutes of cooling time, they were released into the magazine. The protective coating obtained had a thickness of 30 μm and a uniform appearance over the entire length of the pipe.

2nd embodiment

An isocyanate-curing vinyl copolymer was applied to the same tubes as in the first exemplary embodiment. This material also has a flash point above 21 ^° C. and a processing viscosity of 22 seconds in a 4 mm DIN cup. At same as described in the first embodiment, cycle times, the baking temperature was reduced in the ovens at 16O C. Again, it was possible to achieve a pipe coating, which had at a thickness of about ₀ 40 to a uniform appearance.

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3rd embodiment

On the same pipes as in the first embodiment, under the measures mentioned in the first embodiment, a thermoplastic powder coating material based on PVC was electrostatically applied with a commercially available powder spray system at a voltage of 130 kV. A melting temperature ^{of 220 °} C. was used in the ovens. A pipe coating with an average layer thickness of 90 ^ m was achieved, which had a uniform appearance.

- 7 - Claims

509849/0458

Claims (7)

PATENT CLAIMS, '' (Ί). Device for two-stage application, preferably by electrostatic spraying, flooding, airless spraying and curing, baking or melting through a protective coating made of a liquid or powdery material on the outer surface of metal pipes, in particular iron and steel pipes, in one operation, consisting of continuous chain conveyors on which the metal pipes lie horizontally and parallel to each other a path running perpendicular to its longitudinal axes are automatically transportable, according to the patent . (Patent application P 23 28 403.9-45) two with Carrying chain conveyors each consisting of parallel chain strands are arranged one behind the other in a line, the chain strand spacing of which is chosen so that the metal tubes rotatable about their longitudinal axis on one carrying chain conveyor with their end areas and on the other carrying chain conveyor with their burned-in, hardened or melted ones Areas provided with a protective coating rest, with spray booths for applying the protective coating and ovens for curing, baking or melting of the protective coating being arranged in the area of the conveyor section of the carrying chain conveyor, characterized in that at least one further chain strand (1) between the chain strands (1) of one carrying chain conveyor is arranged and the other carrying chain conveyor, its conveyor. stretch overlaps with the conveying route of a carrying chain conveyor, consists of at least two chain strands (8). - 8 509849/0458 2) Device according to claim 1, characterized in that the chain strands (1) of a carrying chain conveyor to those of the other carrying chain conveyor are arranged transversely to their transport direction. 3) Device according to claim 2, characterized in that the chain strands (1, 8) are offset from one another so that the areas provided with a coating on one carrying chain conveyor, the metal pipes (2) on the chain strands (8) of the other carrying chain conveyor rest. 4) Device according to claims 1 Ms 3 » characterized in that between the chain strands (1, 8) of both the one and the other carrying chain conveyor and on the outside of the outer chain strands (8) of the other carrying chain conveyor each have a spray booth (3, 9) and subsequently an oven (7, 12) are attached. 5) Device according to claims 1 to 4, characterized in that a lifting device (4, 10) for the metal pipes (2) is attached in the area below each spray booth (3, 9). 6) Device according to claim 5, characterized in that on the lifting beam of the lifting device (4, 10) located between the side walls of the spray booth (3j 9) and the chain strands (1, 8), rollers (5) each have their axes transverse to the transport direction ) are arranged. 7) Modification of the device according to claims 1 to 5, characterized in that the ovens (7 »12) of each carrying chain conveyor are each combined to form an oven. - 9 -509849/0458 S) modification according to one or more of the claims 1 "to 7, characterized in that in the horizontal areas the carrying chain conveyor is continuous with lifting" bar conveyors are replaced. 50 9849/0 45 8 Blank page