The rope passing method for repair of petrochemical pipelines with spiral flow.

Abstract

Using a spiral flow, a new effective technique for rope passing for repairing pipelines has been developed. With this technique, useful in petrochemical industries, rope could be passed through a straight pipeline 150 meters long and a roll of vinyl tube 50 meters long, however, using a turbulent flow, other conditions being the same, the rope could not be passed through.To obtain a high speed stable spiral flow, a unit with an annular slit connected to a conical cylinder was used. A pressurized fluid was introduced through this slit, and the fluid passing through the conical cylinder was deformed to a spiral flow having its maximum axial flow at the axis due to the Coanda effect and instability.As a result, the rope was attracted to the axial section of the pipe, increasing the ability and the effectiveness for rope passing work.