MULTILAYER POLYPROPYLENE REINFORCED PIPE Russian patent published in 2023 - IPC F16L9/12 

FIELD: pipeline structures.

SUBSTANCE: used for transporting liquid hydrocarbons, namely for oil with a specific gravity within ρ=0.831-0.860 g/cm³ in systems of above-ground field oil pipelines, at negative ambient temperatures. The multilayer polypropylene reinforced pipe consists of a base layer, a barrier layer, a reinforcing layer, a protective layer, a connecting layer and a heat-insulating layer. The main layer is made with a diameter of 315 mm and a wall thickness of 18.7 mm from heat-stabilized polypropylene, which makes it possible to transport oil with a specific gravity within ρ=0.831-0.860 g/cm³ at a temperature of at least +40°C with a pressure of 3.0 MPa. To ensure the absence of diffusion of oxygen and oil vapours with the main layer, a barrier layer is used, which is applied by spiral winding over the main layer, has a thickness of 1.8 mm and is made of liquid crystal polymers with a 50% glass fibre content. The reinforcing layer is made with a thickness of 0.3-0.5 mm from high-strength and high-modulus synthetic threads that can freely and reversibly move in the axial direction with fluctuations in the geometric dimensions of the pipe under the influence of temperature changes and mechanical loads, representing a grid and applied over the barrier layer by winding successive layers.

EFFECT: additional protection against mechanical damage of the main, barrier, reinforcing layers and the connecting layer is provided by a protective layer consisting of a pipe with a thickness of at least 2 mm made of heat-stabilized polypropylene.

1 cl, 4 dwg, 1 tbl