FR2516198A1 - Roughening procedure for ballasting smooth underwater circuits - has irregular particle implanted in resin before polymerisation - Google Patents

Abstract

The procedure fixes a layer of ballast in concrete or other material onto smooth extruded synthetic resin protective covers of metal underwater tubes (2). The ballast forms multidirectional anchoring points with a uniform hold along the total length of the tubes. Before cooling or polymerisation of the synthetic resin (1), finely divided particles of the same resinous material (3,4,5) are placed and welded by their base (6) to form reliefs and cavities (7,8) of different volume and irregular profile. The particles can be sawdust, glass beads or other metal or synthetic material.

Description

 The object of the invention relates to a device for fixing a ballast on the synthetic protective coatings of tubes intended to be immersed, as well as its manufacturing process.

 It is intended for the realization of an adhesion surface to ensure the attachment of the encasing of the weighting concrete to ensure stabilization on the bottom of the submerged "sea lines", the coating of which is formed by a layer of synthetic resin extruded or powdered and smooth, that of high, medium or low density polyethylene.

 In known devices, attempts were made to avoid slippage or movements of the concrete ballast by using the extra thicknesses of the coating of extruded polyethylene in line with the differences in thicknesses or extra thicknesses formed by the strips and left as they are during manufacture; but the depths of immersion were more and more important where the "sea lines" must be deposited, requiring a more and more important tension transmitted to the anti-corrosion and ballast coatings.

 The synthetic resin coatings in extruded or powdered polyethylene have superior adhesion to the coaltar or bituminous coatings hitherto used in tube protection.

 It has also been observed that a concrete ballasting carried out on a coal tar or bitumen coating and responding to a sliding resistance of the concrete of approximately 3 kg cm 2, is not improved in adhesion if it is carried out on a coating in extruded polyethylene with extra thickness limited to the strips.

 On the other hand, the sliding resistance of concrete can reach about 10 kg per cm2, if the adhesion surface is improved on the coatings.

The device according to the invention makes it possible to carry out
dots on the smooth surface of the polyethylene coating
omnidirectional anchors creating a roughness ensuring an attachment of the concrete.

 It consists of spraying onto the complete surface of the coating of extruded polyethylene or formed by any other coating process but before cooling or complete polymerization, of given projections of particles of synthetic resins or other materials such as sand, sawdust, glass beads. , which stick, encrust or weld on the receiving surface.

 In certain applications, in particular on the coating of extruded or powdered polyethylene, a mechanical process is used to promote the bonding of the powder sprayed onto the coating.

In the accompanying drawings, given by way of non-imitative example, of one of the embodiments of the subject of the invention
Figures 1 to 3 show in section and in elevation the products obtained.

 FIG. 4 shows a method of manufacturing the attachment device.

 The polyethylene surface forming the protective layer 1 of the metallic tubular element 2 used for making "sea lines" or submerged pipes is perfectly smooth.

The coating of this surface with concrete was only retained by the differences in thickness of the strips at each of the ends .11 this resulted in an absence of adhesion over the entire length. As a result of capillary effects of surface tension and even of shock, disintegration movements took place, taking away from this ballast its effectiveness in its ballast and protective function.

 These drawbacks are eliminated by making attachment points 3, 4, 5 on surface 1, in a distribution that is homogeneous as a whole as regards their distribution, but anarchic as regards their anchoring distance, orientation and height so as to omnidirectionally forming grip and adhesion surfaces.

 By the use of finely divided particles of synthetic resin of the same nature in FIG. 1, these more or less pronounced protruding attachment points melt at their contact surface 6 so as to form a monolithic bed therewith while creating a relief.

 This inequality and roughness allows the concrete or other amalgam to be inserted between these concave spaces 7, 8.

 The same anchoring profiles are obtained on resin coatings such as epoxy, polyamide etc ... applied in fluidized baths, by electrostatic powdering or spraying by applying to these surfaces finely divided mineral particles 9, 10, including the bases 11 , 12 penetrate sufficiently into the undivided receiving surface, that is to say before polymerization.

 Glass beads 13, 14 and the like can also be applied to these surfaces, with the same functions.

 The methods used for these productions can be adapted to the shape of the steel tubes, either by rotation and translation of the latter, or by translation and rotation of the headlamps and / or applicators.

 Thus it is preferably used to ensure the distribution of the anchoring particles on the surface 16, covering the tube 17 which performs a translational and rotary movement, a spray gun 19 by compressed air 20 sucking the material in the reservoir 18, supplemented by a mechanical applicator 21.

 This gun is connected on the one hand to the reservoir 18 containing the product to be sprayed and to the compressed air generator 20 so that the particles are propelled to be placed on the unpolymerized synthetic resin 16 and then applied with mechanical pressure 21 to s 'fix on the 36osa with a homogeneous distribution as a whole but with a spacing and an anarchic orientation to create functional irregularities.

 However, the materials used to produce the anchoring surfaces and the inlay means may vary within the limit of the equivalents, without thereby changing the general design of the invention which has just been described.

Claims (3)

 10 Device allowing the fixing of a ballast layer of concrete or other composition on the protective coverings in smooth extruded or powdered synthetic resin covering the submerged tubes or "sea lines" in order to achieve anchoring points with omnidirectional profiles, but ensuring hooking uniformly distributed over the entire length of the receiving element, characterized by the implantation before cooling or polymerization of the synthetic resin (1) of finely divided particles but with irregular profiles of synthetic resin of the same nature (3, 4 , 5) sand, sawdust (9, 10) or glass beads (13, 14, - 15) or of metallic or synthetic materials.  20 Device according to claim 1 characterized in that the particles (3, 4, 5) of the same kind as the support (1) are welded by their base (6) and form reliefs and cavities (7, 8) of different volume with irregular profiles.  30 Device according to claim 1 characterized in that the particles of various materials, sand, minerals, plants and others (9, 10) or - beads (13, 14, 15) - are anchored in the synthetic resin (1) not yet polymerized by more or less deep penetration (11, 12) so as to form irregular hollows and projections as regards their implantation, but uniformly distributed as a whole.  4 Device according to claim 1 characterized in that the projected particles are anchored by a mechanical applicator (21).