FLOW STRING (FS) WITH INTERNAL COATING ELIMINATING SEDIMENTS AND METHOD FOR APPLYING THIS COATING Russian patent published in 2009 - IPC F16L58/02 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil producing industry, particularly to preventing asphalt-resin-paraffin sediments (ARPS) on internal surface of flow string (FS). In FS including proper FS with internal coating of a wall there is used polyurethane elastomer of cold moulding as a polyurethane coating; after solidifying coating acquires glossy surface, high adhesion to metal, Shore hardness 50-90 A, uniform thickness of coating, high resistance to wear up to 25 mg, elasticity to 70-75%, and ability to maintain properties of coating within range of temperature from -55 to 100° C. The method of applying coating on internal surface of FS consists in cleaning and de-fatting of internal surface of FS, in injecting material of coating and in its solidifying; injecting of material of coating (polyurethane) is carried out till it fills a circular cavity formed by an internal wall of FS and a puncheon; also roughness of its external surface is not less the 9 surface finish class and should have glossy coating after solidifying; upon final solidifying of polyurethane the puncheon is removed.

EFFECT: preventing asphalt-resin-paraffin sediments.

7 cl, 1dwg