Method of protection of underground pipelines and steel structures against corrosion

 

(57) Abstract:

The invention relates to construction and is used for protection of underground pipelines and steel structures against corrosion. The pipeline is applied bituminous primer followed by imposition of a protective coating, and pre bituminous primer type inhibitor "Travis" in the ratio of 1:500 by weight. Improves corrosion resistance of the coating.

The invention relates to the protection of underground pipelines and underground structures against corrosion.

The predominant use of the invention - the imposition of protective coatings on the surface of underground pipelines and metal structures.

There is a method of protecting equipment from hydrogen cracking (article Ivanov, C. S. Inhibition of hydrogen cracking paints. //Protection from corrosion and environmental protection. - 1994 - 7. - S. 11-12), which consists in applying a primer to the surface equipment and overlay it inhibited paintwork.

The disadvantage of this method is that soil conditions paintwork quickly destroyed.

FR is performance communications backbone. General requirements for protection against corrosion. M: Gosstandart Of Russia. - 1998. - 42 S.), which provides for coating the pipe primer, which is a protective coating and cathodic protection.

The disadvantage of the prototype is that during operation over time in some areas of the pipeline due to poor adhesion with the metal or cathodic delamination between the insulation and the primer is wet, leading to corrosion of the pipeline. Cathodic protection increases the flow of moisture to the pipeline due to the impact forces of electroosmosis in places characterized by partial or complete destruction of the protective coating. As a result, the corrosion process continues intensively, leading to the formation of corrosion damage.

The technical problem solved by the invention is to improve the efficiency of the method by braking factors causing corrosion on the surface of the pipeline.

The invention consists in that the known method of protection of underground pipelines and steel structures, including drawing on the pipe primer and then applying a protective coating according to izona the basis of alkylpyridine in the amount of 1: 500 by weight.

The method is as follows. In coat add corrosion inhibitor "Travis". The mixture is mixed to create a homogeneous mass, then after cleaning the pipe primer is applied to it, and then imposed isolation in the prescribed manner.

The method was implemented in the laboratory test were subjected to two samples:

1. Steel plate HH covered with bitumen primer representing the bitumen dissolved in gasoline in the ratio of 3:1.

2. Steel plate HH was covered with the primer, which is the composition in a proportion of 50 g of bitumen primer added 0.1 corrosion inhibitor "Travis" on the basis of alkylpyridine. As corrosion protection used 3% NaCl solution.

Were conducted electrochemical study of the corrosion rate of the samples. The data obtained were built polarization curves. According Tafelski equations extrapolation was calculated corrosion rate for the first sample, it was 2,710-3mm/year, and for the second sample - 0,61810-3mm/year. In addition, samples were tested in conditions close to real.

The samples were alternately placed in the installations connected to the constant current source. Potential sample-electrolyte supported (-0,65) In HES.

During the experiments for each sample 30 minutes after the experiments the value of protective current to the first image was (-0,34) mA, and the second (-0,13) mA.

Experiments have shown that the invention improves corrosion protection.

The positive effect compared with the prototype is that in the present invention proposed composition is well protected in ground conditions. This increases the efficiency of the method of protection and reduces the accident rate.

The way to protect underground pipelines from corrosion, comprising applying to the pipeline bitumen primer and then applying a protective coating, characterized in that before applying the protective coating of bitumen primer pre-add corrosion inhibitor at a ratio of 1: 500 by weight.

 

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FIELD: construction.

SUBSTANCE: device comprises the assembling-arresting unit which locks the bushing against self-unscrewing. The bushing is provided with a heat insulating material and sealing composition and is made of the self-unscrewing spring, which accumulates mechanical energy. The inner end of the spiral belt is provided with a blade, which is mounted in the vicinity of the face edge of the inner end of the belt and the ends of which are provided with guiding projections. The method comprises setting the assembling-locking unit with the bushing on the pipe end to be welded, assembling the pipe butt by moving the end of the pipe to be welded onto the projections of the bushing and heat insulating material to provide a gap between the pipe faces, unlocking the bushing, and removing the assembling-locking unit. The spiral belt is unwound with sliding with respect to the inner end. The gap size depends on the thickness of the assembling-locking unit. The projections of the blade cooperate with the side edges of the belt turns and cause the sealing composition to move thus providing a protecting roll.

EFFECT: enhanced reliability of the pipeline.

3 cl, 6 dwg

FIELD: corrosion prevention technologies.

SUBSTANCE: method includes serial application of layers of polymer compositions to metallic surface, while serial layers of polymer compositions are made with various thermal expansion coefficients. As said polymer composition polyurethane compound is used with special admixtures and filling agent, influencing thermal expansion coefficient of covering layer, and content of said filling agent in each following layer is set less than content of said filling agent in previous layer.

EFFECT: higher efficiency.

2 cl, 9 ex

FIELD: construction.

SUBSTANCE: protecting coating comprises several layers. One of the layers is made of an elastomer. The elastomeric sealing layer is made of a calendered raw rubber which is protected with the fiber glass fabric from both sides. The fiber glass fabric is impregnated with phenol-formaldehyde resin with subsequent solidifying and vulcanizing the rubber.

EFFECT: enhanced reliability.

1ex

FIELD: construction.

SUBSTANCE: method comprises removing the exhaust insulation from the pipeline, preparing the outer side, applying the primer coat, and winding belt coating made of oil polymer. The belt coating is reinforced with glass net.

EFFECT: enhanced reliability.

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