CS214997B1 - Method of anticorrosion protection of the pipeline fittings - Google Patents

Description

CZECHOSLOVAK SOCIALIST REPUBLIC (19) DESCRIPTION OF THE INVENTION FOR COPYRIGHT CERTIFICATE 214997 (11) (Bl) (51) Int. Cl3 F 16 L 58/00 (22) Registered 07 12 78 (21) (PV 8109-78) (40) Published 10 09 81 OFFICE AND DISCOVERY OFFICE (45) Published 15 09 84 (75)

Author of the invention RADOMIL MILAN, BOUBELA LUBOMÍR ing., DAVIDOVÁ HELENA ing., PRAGUE (54) Method of anticorrosive protection of pipeline fittings

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for the passive anti-corrosion protection of fittings for pipelines for conveying gases and oils comprising the application of an insulating layer and the application of a further protective layer of plastic material.

Passive anti-corrosion protection of storage facilities, consisting of an insulating and protective layer, known. For example, warm liquid bitumen is applied to the cleaned metal as an insulating layer, which adheres well to the metal. However, such an insulating layer has little resistance to mechanical influences and protects it with sheathing or bandages. The following factors influence the protection: weather conditions in the insulation, the expertise and diligence of the insulation workers, the mechanical damage to the insulation layer, the leakage errors, and the gaps created by the irregularities of the external geometry, in particular the fittings.

Another known protection consists of an insulating layer of epoxy resin on which a plastic band, a mass, is wound. The epoxy resin insulating layer exhibits excellent electrical properties with a breakdown of about 50 kV / mm, yet the technical problem is again to provide a thin insulating layer against mechanical damage during transport or when deposited in the ground, especially in a rocky subsoil, with a protective layer. The winding of the plastic protective bandage creates the same difficulties as mentioned in the winding of the bitumen bandages, especially the winding of the bandages on the irregular external-geometric shapes of the fittings. In addition to the aforementioned method of winding the bandages, the drawback of the winding operation and the considerable cost of the technological equipment are considerable. Furthermore, a belt for mechanical protection of insulated storage pipes is known which consists of a cooled melt consisting of a 1 mm to 20 mm thick layer consisting of a mixture of 50 to 99.8% of atactic polypropylene dewatered, 0.1 to 10% of a rubber solution in an organic solvent in 1 to 50 wt. parts to 99 to 50 wt. and from about 0.01% to about 40% of a bulk filler reinforced with a liner mechanically more resistant than the composition, wherein an electrically nonconductive particle size material of up to about 3 cm in diameter, preferably in the form of granules, is embossed on its surface.

This mixture has the disadvantage that it has only very limited anticorrosive effects and does not adhere to its substrate. Since one belt, which is portable and consists of a cooled melt, cannot be used to protect insulating materials with a rugged surface.

The aforementioned disadvantages are eliminated by the method of corrosion protection of pipe fittings, the principle of which is that the insulation layer ΠΗΪ7

Claims (1)

BACKGROUND OF THE INVENTION The present invention relates to a method for passive corrosion protection of gas and oil pipeline fittings comprising the application of an insulating layer and the application of an additional protective layer of plastic. Passive corrosion protection of storage devices, consisting of an insulating and protective layer, is known. For example, warm liquid bitumen, which adheres well to the metal, is applied to the cleaned metal as an insulating layer. However, such an insulating layer has little resistance to mechanical influences and is therefore protected by sheathing or bandages. The quality of such protection is influenced by the following factors: weather conditions for insulation performance, expertise and diligence of insulation workers, mechanical damage to the insulation layer, leakage errors and gaps due to irregularities in external geometric shapes, especially fittings. Another known protection consists of an epoxy resin insulating layer on which the protections are wound, a plastic bandage, a mass bandage. The epoxy resin insulating layer exhibits excellent electrical properties with a breakdown of about 50 kV / mm, but the technical problem is again to provide a thin insulating layer against mechanical damage during transport or storage in the ground, especially in stony ground, with a protective layer. Winding of the protective plastic bandage gives rise to the same problems as those mentioned for the winding of the hitumen bandages, in particular the winding of the bandages to irregular external geometric shapes in fittings. In addition to the aforementioned defects in the winding of the bandages, the great disadvantage is the winding effort and the considerable cost of the technological equipment. In addition, a strip for the mechanical protection of insulated conduits is known which consists of a cooled melt consisting of a 1 mm to 20 mm thick layer consisting of a mixture of 50 to 99.8% water-free atactic polypropylene, a 0.1 to 10% solution of rubber in organic % solvent in a ratio of 1 to 50 wt. parts to 99 to 50 wt. and from 0.01 to 40% of a bulk filler reinforced with an insert which is mechanically more resistant than the mixture, and an electrically non-conductive lump material of particle size up to 3 cm, preferably in the form of granules, is anchored on its surface. This mixture has the disadvantage that it has only very limited anti-corrosion effects and does not adhere firmly to its substrate. Since it is a belt that is portable and consists of a cooled melt, it cannot protect the insulation of a rugged surface. The above mentioned disadvantages are eliminated by the method of corrosion protection of pipeline fittings, which is based on the fact that at the temperature of 120 to 150 ° C a protective layer of thickness from 0.5 cm to 5 cm of atactic polypropylene with 0.1 to 10 % of an atactic polypropylene miscible inhibitor, and 0.1 to 50% of a particulate mineral filler. The advantage of the invention is that when both the insulating layer and the protective layer are damaged down to the metal of the fitting, due to the inhibitor dispersed in the protective layer, the inhibitor substance is combined with the metal, thus preventing further corrosion process. Another advantage of the anticorrosive protection according to the invention is the perfect adhesion of the protective layer to the epoxy resin insulation layer, which is not subject to change when the protective layer is applied, the coating is easy to apply, whether by coating or embedding. the thickness of the coating is lightly applied as required. The protective layer is very cheap to manufacture, since waste atactic polypropylene is used. The principle of the invention is further explained by examples. Example I. The pre-cleaned and degreased fitting was provided with a 160 µm fluid-thick epoxy resin insulating layer, sold under the designation KOMAXIT E 2120/0199. The fitting so treated was inserted into the formwork so that the formwork overlaps the nearest fitting surface by at least 5 mm. The space between the fitting and the shuttering was poured with a mixture of waste anhydrous atactic polypropylene with 30% fine fly ash from electrofilters and 5% minium at 130 ° C. Example II. In the same manner as in Example I, the fitting was cleaned, degreased and provided with an epoxy resin insulating layer sold under the designation KOMAXIT E 2120/0100. The protective layer was created by coating the armature with a layer of a mixture of waste atactic polypropylene with 20% fine fly ash from electrofilters and 1% potassium dichromate. The coating was performed at 140 ° C and repeated several times until the layer thickness was 6 mm. Various possibilities of applying the insulating protective layer 1 are well known to those skilled in the art and are not further described in addition to the examples. SUBJECT Method for the corrosion protection of pipeline fittings consisting of the application of an epoxy resin-based insulating layer and the application of an additional protective layer of plastic material, characterized in that it is applied to the insulating layer at a temperature 120 to 150 [deg.] C. a protective layer of 0.5 to 5 cm thickness of atactic polypropylene with 0.1 to 10% of an atactic polypropylene miscible inhibitor and 0.1 to 50% of a free-flowing mineral filler.