The invention relates to a sealing element for sealing pipelines, having an inflatable bellows which in the inflated state causes the sealing element to bear against an inner wall of the pipeline.
Such sealing elements are also known as xe2x80x9cpipe sealing padsxe2x80x9d or xe2x80x9cplug bagsxe2x80x9d and have a wide variety of possible uses. They are used, for example, for pipe and drain plugs, for leakage tests, measurements of flow rate and in many other sectors. In this case, the sealing element is put into the pipeline and inflated, in the course of which the outer sleeve of the bellows comes into contact with the inner wall of the pipeline and thereby ensures sealing.
The sealing elements known from practice are obtainable for various pipe diameters. However, the known sealing elements can only satisfactorily seal clean and smooth inner-wall surfaces of pipelines. In the event of impurities, unevenness or damage to the pipelines, pressure-tight, reliable sealing often cannot be achieved.
Communication cables or conduits with cables have started to be laid in drainage channels, and these communication cables or conduits do not permit the use of the conventional sealing elements, since the sealing elements are not flexible enough to seal the cavity between cables or conduits and pipe inner wall.
A separate segment piece which has appropriate recessed portions for the laid cables or leads has therefore been provided in DE-U-297 20 570. This segment piece is adapted to the diameter of the pipeline and is made of elastic material, which is arranged between the pipe inner wall and a pipe sealing pad.
However, this sealing system does not take into account the problems associated with any impurities, unevenness or damage to the pipe wall. Furthermore, this sealing system can only be attached at locations accessible by hand. The sealing of a pipe section which is not accessible from the shafts is not possible. Furthermore, a relatively large amount of time is required in order to make the seal, so that this sealing system is unsuitable for rapid use in the event of an accident. Furthermore, the segment pieces must be adapted to the cables and conduits laid in the pipeline in order to ensure sealing which is as effective as possible.
The object of the invention is therefore to specify a sealing element for sealing pipelines according to the preamble of Claim 1 which on the one hand is easy to manipulate and on the other hand ensures reliable sealing even in pipelines with cables and/or conduits.
This object is achieved according to the invention by the features of Claim 1 in that, on its outer side bearing against the inner wall of the pipeline, at least on sections of its circumference, the sealing element has a dimensionally stable, easily deformable gel which in the inflated state of the bellows comes into sealing contact with the inner wall of the pipeline.
The gel used is a gel having crosslinked molecules, form memory and good, reaction-free flow behavior under compression. The cohesion forces of the molecules in this gel are greater than the adhesion forces of the molecules relative to, for example, the inner wall of the pipeline or relative to cables laid in the pipe. Firstly, cavities, e.g. between unevenness and cables, can be filled in a sealing manner with such a gel. On the other hand, such a gel ensures that the sealing element can be removed again from the inner wall of the pipeline without problems, the gel returning without great wear into its initial state, so that the sealing element can be fitted and removed many times.
Further developments of the invention are the subject matter of the subclaims.
In an especially preferred embodiment, the bellows has the gel on its entire outer side facing the inner wall of the pipeline. This is especially advantageous if, for example, older pipelines having very uneven inner walls due to deposits and/or corrosion are to be sealed.
In a further preferred embodiment, the bellows of the sealing element is cylindrical and has a recess which extends in a ring shape in the circumferential direction and contains the gel.