EP0858533B1 - Waterstop with injection channel - Google Patents

Abstract

A waterstop of the type which comprises a central, elastically deformable portion (1) having two embedment lugs (2, 3) extending from the central portion in substantially the same plane and having securing means (4, 5), wherein the embedment lugs (2, 3) in addition are equipped with injection channels (6, 7) for chemical injection, formed in on piece with the lugs (2, 3) and equipped with microholes for injection.

Description

The present invention relates to a waterstop of the type which comprises a central, elastically deformable portion with two embedment lugs extending from the central portion and substantially in the same plane, and having securing means.

It is well-known that concrete structures which are under water pressure make heavy demands on the composition of the concrete casting in general and the concrete joints in particular.

The ideal joint between two concrete castings which it is desired and endeavoured to obtain is one without cracks, crevices, gaps and similar. The problem of leakage may occur in particular when concrete walls are cast on a precast concrete foundation, and to repair cracks and crevices of this type a great number of means have been suggested in the prior art.

Recent developments and research in this field have resulted in a system which today is marketed under the name "Fuko", and which comprises a tubular core of a compact, strong material along which, in the longitudinal direction thereof, there are provided grooves, which in turn are provided with through-going perforations in the bottom thereof. These grooves are then covered with loose lamellae so that the overall profile of the tube is roughly circular.

The purpose of these lamellae is to prevent the concrete mass that is cast from blocking the perforations in the tube whilst ensuring that even at low pressure the injection mass can be squeezed out of the feed pipe and into the surrounding cracks and crevices.

In order to improve this technique there is proposed in Norwegian Application P933815 (WO-A-95/11352) a tube for chemical injection in concrete comprising an injection material insertion portion and a compressible porous material attached thereto, and where the invention is characterised in that the insertion portion comprises at least two channels, running side by side, preferably cast in one piece and in the form of strips, in the outer walls of which there are formed micro-apertures for throughflow from within and outwards under a predetermined internal positive pressure.

These micro-apertures are formed in such a way that owing to the elasticity of the wall material they function as non-return valves.

Also, in cast walls where the walls are cast in blocks there is a danger of water leakage and so-called waterstops have therefore been developed consisting of a central, elastically deformable portion with two lugs projecting out therefrom and having securing means, where the lugs are designed to be cast into the adjacent concrete blocks; cf. SE-C-172 479.

When the concrete shrinks the embedment lugs are retained whilst the elastically deformable central portion is deformed, thereby ensuring sealing.

However, practice has shown that it may still be difficult to prevent seepage of moisture as moisture can migrate from the inlet side along the waterstop embedment lug inside the concrete, around said lug and back to the joint to seep then into the space it is desirable to keep dry.

In order to remedy this, attempts have been made to combine such waterstops with devices for chemical injection of the type described above, i.e., especially of the type which go under the name "Fuko", or similar.

However, this is a complex process as the waterstop and the tube must be joined and secured to one another on both sides in such a way that the result is very costly, both because the injection tube in this form is relatively expensive and because of the time-consuming labour.

To improve this technique it is now proposed to cast waterstops and injection channels in one piece, where the injection channels are of the type described above with reference to NO P933815 (WO-A-95/11352).

Accordingly, the present application relates to a waterstop of the aforementioned type which is characterised in that the embedment lugs, in addition to the securing means, are equipped with injection channels for chemical injection, formed in one piece with the lugs and equipped with microholes for injection.

The invention will be described in more detail with reference to the attached figure.

Centrally, there is a provided a deformable portion (1), here in the form of a pipe, from which pipe there extend two embedment lugs (2,3).

A circular pipe is shown, but this may of course be of any desirable and suitable shape, and it is only choice of material, economy and individual wishes which set limits.

The two lugs (2) and (3) are equipped with securing means in the form of flanges (4) and grooves (5).

These securing means are conventional and the embodiment shown is only to serve as an illustration.

In order to prevent moisture from migrating nonetheless from the joint out along the embedment lug, therearound and back to the joint, injection channels (7) are provided on the embedment lug, formed in one piece with the waterstop and in addition equipped with microholes of the type which under a certain positive pressure allows the chemical injection mass to be squeezed out, but which otherwise because of the elasticity of the material acts as a non-return valve.

Should it prove necessary, the injected chemical injection mass will effectively and rapidly seal the moisture migration path, thereby ensuring a sealed joint.

There may of course conceivably be more than one injection channel on either side of the central portion even though the illustrated embodiment has only one on each lug.

The withdrawal of injection nozzles and end plugging by division into sections is conventional technology and will not be discussed in more detail here.

In comparison with the prior art the product according to the invention is simple, easy to produce compared with the sophisticated embodiments of the prior art, and comes in a complete unit which does not require the mounting and affixing of additional equipment.

The invention therefore represents a considerable advance in this technical field which results in both cheaper equipment and simpler handling.

Claims (1)

1. A waterstop of the type which comprises a central, elastically deformable portion (1) having two embedment lugs (2,3) extending from the central portion in substantially the same plane and having securing means (4,5), characterised in that the embedment lugs (2,3) in addition are equipped with injection channels (6,7) for chemical injection, formed in one piece with the lugs (2,3) and equipped with microholes for injection.

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