DE29817966U1 - Conduit pipe for the transport of liquid or gaseous environmentally hazardous media - Google Patents

Description

Pipe for the transport of liquid or gaseous environmentally hazardous media

Description

The invention relates to a conduit for the transport of liquid or gaseous media according to the preamble of claim 1.

From DE-A-33 02 450 a conduit pipe is known which consists of a helically corrugated metal pipe, a bitumen-based corrosion protection layer resting on the metal pipe and filling the corrugation contour, and an outer jacket made of plastic resting on the inner pipe or the corrosion protection layer.

Such a pipe can be manufactured in great lengths and is so flexible that it can be wound up on portable cable drums or wound into a coil like an electrical cable. It is transported to its place of use either on a cable drum or as a coil and can be laid there like an electrical cable.

In order to connect such a pipe to a fitting, it is necessary to expose the end of the inner pipe. To do this, the casing and the anti-corrosive layer must be removed. This is a very time-consuming process. Another disadvantage of the known pipe is that the anti-corrosive compound filling the corrugation valleys and the smooth plastic casing have a strong influence on the bendability. As a result, only a bending radius of 5 D at most can be achieved with this pipe, i.e. five times the outside diameter.

From DE-GM 297 10 258 a pipe according to the preamble of claim 1 is known, in which a plastic film with pre-tension is wound onto the corrugated inner pipe so that the plastic outer pipe can be inserted into the corrugation valleys. The outer contour of the plastic outer pipe is corrugated.

In one embodiment, the plastic outer tube has ribs that taper towards the inside and are supported on the wave crests. This achieves improved permeability for gases and liquids in the longitudinal direction of the tube, but does not achieve a mechanical clamping between the inner tube and the outer tube.

Based on this state of the art, the object of the present invention is to achieve, on the one hand, a mechanical clamping between the inner corrugated pipe and the plastic outer casing and, on the other hand, a sufficiently large longitudinal permeability. In addition, profiling of the outer surface should be avoided.

This object is achieved by the features defined in the characterising part of claim 1.

The essential advantage of the invention is that a sufficiently large monitoring space is created between the inner pipe and the outer pipe, and the inner pipe is secured in the outer pipe against longitudinal displacement.

Further advantageous embodiments of the invention are covered in the subclaims.

The invention is explained in more detail using the embodiments shown schematically in Figures 1 to 3.

Figure 1 shows a side view of a conduit pipe according to the teaching of the invention.

There, 1 designates a helically corrugated metal pipe, preferably made of copper or stainless steel, which is manufactured in a continuous process from a metal strip by forming the metal strip into a slotted pipe, welding the long edges of the metal strip and then corrugating it. An outer pipe 2 made of plastic, preferably polyethylene, is extruded onto the corrugated metal pipe. The outer pipe 2 has a large number of inwardly projecting projections 3 evenly distributed over the circumference, which are formed by the mouthpiece of the extruder. When the outer pipe 2 is extruded, it is ensured that the projections 3 are formed into the corrugation troughs of the inner pipe 1, for example by creating a negative pressure between the inner pipe and the outer pipe or by the projections penetrating the corrugation troughs due to thermal contraction. It is important that this achieves a positive connection between the inner pipe 1 and the outer pipe 2.

At the right end of Figure 1, a view of the inner surface of the outer pipe is shown. Here, the projections 3 can be seen, between which channels 4 are formed running in the longitudinal direction of the pipe. The channels 4, together with the helical trough 5, form a monitoring space which has a connection to a leak monitoring device in the area of the fittings.

Figures 2 and 3 each show a section through a conduit pipe according to the invention. The projections 3 preferably have a trapezoidal cross-section. It is also clearly visible that the projections only slightly engage the wave valleys 5, so that the longitudinal channels 4 are continuous and are not interrupted by a wave crest of the inner pipe. This measure results in a reliably monitored gap between the inner pipe 1 and the outer pipe 2, which makes this conduit pipe particularly suitable for the transport of petrochemical liquids or gases.

Claims (3)

-gateopnsprüche 1. Pipe for the transport of liquid or gaseous environmentally hazardous media, consisting of a corrugated inner pipe, a plastic outer pipe resting on the inner pipe and a space between the inner pipe and the outer pipe that can be monitored for leaks, the outer pipe having inward-pointing projections running in the direction of the longitudinal axis of the pipe, characterized by the following features a) the outer surface of the outer tube (2) is smooth b) the projections (3) penetrate into the wave valleys and form a positive connection between the inner tube (1) and the outer tube (2) c) the material-free cross-section of the space between the inner pipe (1) and the outer pipe (2) is at least 10% and at most 50%. 2. Conduit pipe according to claim 1, characterized in that the projections (3) have a substantially rectangular or trapezoidal cross-section. 3. Conduit according to claim 1 or 2, characterized in that the radial extent of the incisions located between the projections (3) is greater than the penetration depth of the wave crests into the projections (3).