DE2362677A1 - Metal tubing with anti-corrosive inner - with roughened metal liner between outer and inner plastics tubing - Google Patents

Abstract

The inner tubing made of plastics, is initially inserted into the outer tubing with a clearance therebetween and is fixed into position by contraction of the outer tubing. The liner is made of sheet metal and is provided at least at its interior with small projections. The liner is inserted into the clearance before the contraction process and during that process the projections of the liner become embedded in the outer surface of the plastics inner tubing thereby to inhibit differential expansion between the inner and outer tubing. The liner may be a spirally wound or slotted tube.

Description

Patent _Engineer-to -JL ₄ .. December 1973

Meerbusch 1 Bommertweg 1

Patent application

of the company
Pampus KGr
4156 Willich 3
On the north canal

Metal pipe with an anti-corrosive lining

The present invention relates to pipes with an anti-corrosive plastic lining. ¥ e due to the different thermal expansion of pipe and lining, especially then, if the pipes are metal, both pipes must be anchored to one another to prevent wrinkles to avoid the lining. Appropriate anchoring takes place, for example, by that a plastic pipe, the later lining, inserted into a larger jacket tube and that the latter is then reduced in diameter to such an extent until both tubes are pre-tensioned against each other over their entire length. Thereby the jacket pipe made of metal previously roughened on its entire inner surface in order to ensure the adhesion of both pipes

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to enlarge along its entire length and the "pushing" of the inner tube and the resulting to avoid possible wrinkling. The plastic tube is a little longer than the corresponding pipe section made of metal, the protruding ends are folded radially outwards and wedged between the puddles of adjacent outer tubes.

These lined pipes have become in the Proven in practice. However, they have one disadvantage: the mechanical roughening of the The inner surface of the metal tube, for example by embossing rollers, is complicated and expensive. aside from that this is partly destroyed again when the metal pipe is subsequently reduced.

The invention is intended to provide a remedy here. You achieve this in that between the two pipes a sheet metal tube roughened at least on the inside is provided.

A sheet metal strip that only subsequently becomes a Pipe is bent or helically wound, can easily be in front of - if necessary continuous - roughen deformation. The roughening can be that of a grater, for example correspond. A need to connect

the seams of the pipe do not exist. It is even possible to have wide joints between the butting Sheet metal strips are available, for example, if for different pipe diameters For reasons of simplification, only one sheet width should be used.

The use of a non-closed sheet metal pipe or slotted pipe for fixing the inner plastic tube also has the advantage that in the subsequent reduction in diameter of the outer metal jacket pipe that is relatively thin sheet metal tube anchoring is not subject to compression and thus to buckling can lean inward. Rather, the diameter reduction is due to the joint of the slotted tube compensated.

Reducing the diameter of the jacket tube can increase the force-locking connection of the pipe system go so far that the diameter of the inner pipe still has a certain Experience reduction.

An embodiment of the invention is shown in the drawing. It shows:

Fig. 1 shows a jacket pipe with an inserted plastic pipe and a sheet metal pipe

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between these two, namely shown before the diameter reduction of the outer tube, and
Pig. 2 the tubes according to FIG. 1 in the finished state.

In FIG. 1, an outer jacket tube is denoted by 1. In this a plastic tube 2 is inserted. Between the two there is a sheet metal tube 3 which is provided with a roughening k in the manner of a grater. For reasons of better illustration, the whole is shown before the diameter of the jacket tube 1 is reduced.

Figure 2 shows the jacket pipe 1 with the plastic pipe 2 as an anti-corrosive lining in the finished state. The roughening k of the sheet metal pipe 3 has dug into the outer surface of the plastic pipe 2 as a result of the reduction in the diameter of the jacket pipe 1. In this way, the plastic pipe 2 is fixed over its entire length in the jacket pipe 1, the sheet metal pipe 3 allowing expansion of the plastic pipe 2 only in accordance with the length expansion of the sheet metal.

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Claims (3)

Claims Metal pipe with an inserted plastic pipe as an anti-corrosive lining, both of which After a diameter reduction of the outer tube, the pipes rest against one another with pre-tension, characterized by a sheet metal tube (3) roughened at least on the inside between the two tubes (1, 2). 2. Metal pipe with an anti-corrosive lining and a roughened Bleqhrohr according to claim 1, characterized in that the sheet metal tube (3) consists of a helically wound Sheet metal strip consists. 3. Metal pipe with an anti-corrosive lining and a roughened sheet metal pipe according to claim 1, characterized in that the roughening (h) corresponds to that of a grater. k. Metal tube with an anti-corrosive lining and a roughened sheet metal tube according to Claim 1, characterized in that the sheet metal tube (3) is designed as a slotted tube. 509825/0597 Blank page