Scraper for inhibiting corrosion in the arch of a pipe carrying a multiphase corrosive liquid

Autonomous scraper for the anti-corrosion treatment of a pipe (10) wherein flows, in a stratified, wavy or wavy-stratified regime and under pressure (P), a corrosive multiphase liquid that contains a liquid phase (12) that flows off at the lower part of the pipe and to which is added a corrosion inhibiting liquid at the beginning of the pipe, and a gaseous phase (14) that is located at the upper part of the pipe or arch (18), wherein said scraper comprises:

• a cylindrical casing (20) mounted with clearance inside the pipe and equipped on its periphery with watertight means (27) that separate, within the pipe, an upstream side where said pressure (P) prevails from a downstream side, so that the casing is axially driven along the pipe under the effect of the pressure (P);
• means of uptake and projection (22, 30) carried by the casing located downstream from the latter;
• and
• autonomous engine means (24, 26) used to activate said uptake and projection means so that they take up the liquid in said liquid phase as the casing moves in the pipe and project it onto the arch;
• characterized by the fact that said means of uptake and projection are comprised of a revolving part (22, 30) driven in rotation by the engine means, where a portion of said revolving part is immersed in the liquid phase (12) and a non-immersed portion is close to the arch.

Autonomous scraper for the anti-corrosion treatment of a pipe (10) wherein flows, in a stratified, wavy or wavy-stratified regime and under pressure (P), a corrosive multiphase liquid that contains a liquid phase (12) that flows off at the lower part of the pipe and to which is added a corrosion inhibiting liquid at the beginning of the pipe, and a gaseous phase (14) that is located at the upper part of the pipe or arch (18), wherein said scraper comprises:

• a cylindrical casing (20) mounted with clearance inside the pipe and equipped on its periphery with watertight means (27) that separate, within the pipe, an upstream side where said pressure (P) prevails from a downstream side, so that the casing is axially driven along the pipe under the effect of the pressure (P);
• means of uptake and projection (22, 30) carried by the casing located downstream from the latter;
• and
• autonomous engine means (24, 26) used to activate said uptake and projection means so that they take up the liquid in said liquid phase as the casing moves in the pipe and project it onto the arch;
• further comprising a guide (28, 28′) carried by the casing downstream from said means of uptake and projection (22, 30), where the diameter of said guide is slightly smaller than the inner diameter of the pipe so as to push back the liquid that is downstream from said means of uptake and projection.

Autonomous scraper for the anti-corrosion treatment of a pipe (10) wherein flows, in a stratified, wavy or wavy-stratified regime and under pressure (P), a corrosive multiphase liquid that contains a liquid phase (12) that flows off at the lower part of the pipe and to which is added a corrosion inhibiting liquid at the beginning of the pipe, and a gaseous phase (14) that is located at the upper part of the pipe or arch (18), wherein said scraper comprises:

• a cylindrical part (38) mounted with clearance inside the pipe, so that the cylindrical part is axially driven along the pipe under the effect of the pressure (P);
• a canal (40) with an entry opening that opens out in the gaseous phase (14) located upstream from the cylindrical part and lets a gas flow pass through;
• a by-pass (42) that enables a discharge flow to be taken from the gas flow passing through canal (40), wherein the bypass (42) has an exit opening that opens out in the liquid phase located downstream from the cylindrical part;
• means of projection (44) provided at a downstream side of the cylindrical part, wherein said means of projection are comprised of a nozzle (44) attached in said exit opening that enables the emission of the gas discharge into the liquid phase located downstream from the cylindrical part, where said nozzle is turned in such a way that the gas ejected into the liquid phase projects some of this liquid onto the arch (18);
• and a ballast weight (46) attached to the cylindrical part so as to hold it in an angular position in which the nozzle is constantly immersed in the liquid phase.

Autonomous scraper for the anti-corrosion treatment of a pipe (10) wherein flows, in a stratified, wavy or wavy-stratified regime and under pressure (P), a corrosive multiphase liquid that contains a liquid phase (12) that flows off at the lower part of the pipe and to which is added a corrosion inhibiting liquid at the beginning of the pipe, and a gaseous phase (14) that is located at the upper part of the pipe or arch (18), wherein said scraper comprises:

• a hollow cylindrical reservoir (48) mounted with clearance inside the pipe and equipped on its periphery with watertight means (27) that separate, within the pipe, an upstream side where said pressure (P) prevails from a downstream side, so that the reservoir is axially driven along the pipe under the effect of the pressure (P);
• and
• means of projection (30) carried by the reservoir located downstream from the latter;
• characterized by the fact that said hollow cylindrical reservoir (48) has a back wall (52) in which is pierced an entry opening (56) that opens out in the gaseous phase (14) located upstream from the reservoir and a front wall with an exit opening (58), where a piston (54) is mounted in the reservoir in an initial position where it is applied against the back wall so as to free up as much volume as possible in the reservoir, where this volume is filled with a reserve of corrosion inhibiting liquid (50), where said piston moves inside the reservoir toward the front wall under the effect of the pressure from the gaseous phase that is exerted on it through the entry opening and thus progressively expulses the corrosion inhibiting liquid through the exit opening toward said means of projection,
• wherein said scraper further comprises autonomous engine means (24, 26) used to activate said projection means so that they project said corrosion inhibiting liquid onto the arch.

Autonomous scraper for the anti-corrosion treatment of a pipe (10) wherein flows, in a stratified, wavy or wavy-stratified regime and under pressure (P), a corrosive multiphase liquid that contains a liquid phase (12) that flows off at the lower part of the pipe and to which is added a corrosion inhibiting liquid at the beginning of the pipe, and a gaseous phase (14) that is located at the upper part of the pipe or arch (18), wherein said scraper comprises:

• a hollow cylindrical reservoir (48) mounted with clearance inside the pipe and equipped on its periphery with watertight means (27) that separate, within the pipe, an upstream side where said pressure (P) prevails from a downstream side, so that the reservoir is axially driven along the pine under the effect of the pressure (P);
• characterized by the fact that the reservoir contains two concentric cylindrical envelopes (62, 64) with a common back wall in which is pierced an entry opening (56) located at the level of the gaseous phase (14) and two respective front walls where an exit opening (68) is pierced in that of the inner envelope, the annular space between the two envelopes is partially filled with a ballast weight (46) so that the reservoir maintains an invariable angular position in the pipe, and the outside envelope is equipped along its entire upper section with a brush (30) that is in contact with the arch and has a plurality of exit openings (60) pierced directly opposite the brush, where the inner envelope contains a piston (54) initially applied against the common back wall so as to free up the maximum space possible in said envelope and fill it with a reserve of corrosion inhibiting liquid.