Unbound flexible pipe for making flexible hoses for transporting fluids under pressure, in particular rotary hoses for injecting of mud into rotating petroleum drilling or turbodrilling

摘要

An anti-penetration layer is placed around the internal layer, formed using at least one means of winding (9) a band with joining edges with high mechanical characteristics. This layer is designed to prevent flow of the internal polymer layer into the gaps in the armour layer. The armour angles of the crossed armour layers are different. The hose comprises from inside to outside, an internal polymer layer (2), at least two crossed armour layers (4, 5) made of wire rolled helically at opposite angles (A, B) close to the equilibrium angle of 55 deg. and on average centred on a value near to the equilibrium angle, and an external polymer layer (8). The difference between the angles A and B is between 4 and 10 deg., preferably between 6 and 8 deg. At least one adjacent flexible layer (4-1, 6-1) penetrates at least one armour wire (4-2, 6-2) at least partially. The flexible layer is a natural or synthetic elastomer. The armour wire which can penetrate into the flexible layer is a round wire or strand. The flexible layer for the internal layer is placed under the wire winding which can penetrate it and the flexible layer for the outer layer is placed on the wire winding which can penetrate it. The anti-penetration layer is made of one or more windings of a long element with high mechanical characteristics, with short pitch with an angle close to 70 deg. These windings are placed under the armour layers and are made of an aramid fibre such as Kevlar. The hose has only two armour layers and the winding angle A of the lower layer is greater than the angle B of the upper layer. Alternatively, the hose has a first pair of armour layers and another alternated or embedded layer or pair of crossed armour layers. The angle of winding of the additional layer or pair of layers is (are) chosen to be equal to the angles of winding of the first pair. An independent claim is made for an injection hose for drilling mud made of such a hose.