| abstract |
As the first object, the present invention intends to provide high-pressure composite pipes which show remarkable pressure resistance and optimum applicability in various uses and which can be economically manufactured in a light weight. As the second object, the present invention intends to provide a joining method which is capable of firmly joining the high-pressure composite pipes in a simple operation, firmly joining the high-pressure composite pipes by reinforcing the joint strength at the butt-fused area, and making a joint area adjustable to strain of the high-pressure composite pipes. To achieve these objects, a high-pressure composite pipe of the present invention comprises a pipe-shaped inner layer made of a synthetic resin, a reinforcing layer made of a stretched polyolefin resin sheet and wound on an external circumferential surface of the inner layer, and an outer layer made of a synthetic resin and disposed on an external circumferential surface of the reinforcing layer. The winding direction of the reinforcing layer is oriented at a predetermined angle relative to the axis of the pipe. Between the inner layer and the reinforcing layer and between the outer layer and the reinforcing layer, adhesion layers having affinity to these layers are interposed. The joining method of the present invention is a method for joining the above high-pressure composite pipes, and comprises the steps of: heating and melting an end of each high-pressure composite pipe; flaring the melted end of each high-pressure composite pipe, with a diameter thereof gradually enlarging toward an end face thereof; and butting the flared ends of both flared high-pressure composite pipes together and fusing internal circumferential surfaces of their inner layers, with their reinforcing layers being turned outwardly. <IMAGE> |