Strong, flexible laminar thermoplastic pipe - has innermost impervious lining bonded to mechanically strong layer, then braiding for reinforcement, and outermost thermoplastic sleeve

摘要

A laminar wall thermoplastic pipe for use in safety systems has an inner pipe, bonding layer, braiding and an outer pipe. The inner pipe consists of two layers bonded together, one of which is cross-linked; this inner liner is bonded to the braiding and then the outermost pipe. Prefd. materials are polyamide for the innermost and outermost layers, and a thermoplastic resin for the adhesive used. To improve the mechanical strength of the end prod. it can contain two layers of braiding instead of one. The two layers making up the inner pipe are used because the one provides the mechanical strength and the other the imperviousness to the liq. or gas passing through. The two can be coextruded. Alternatively a cross-linking operation can be used. The braiding layer assists in transmitting stresses from one face to the other. ADVANTAGE - The structure of the pipe makes it impervious to liqs. carried (e.g. liqs. which are environmentally unfavourable). They are flexible yet resistant to buckling. They withstand high pressure and temp. and are wear-resistant.