Study on field applicability of a cleaning machine for marine growth removal in seawater pipelines

Abstract

In a seawater intake facility, the proliferation and inflow of marine life impede the flow of seawater, thereby hindering the normal operation of offshore plants. To address this issue, it is necessary to use appropriate device for cleaning the fouled intake pipe, and particularly devices that are suited to dealing with polymer pipes over 2000 mm in diameter. This study aimed to improve the field applicability of a winch jig cleaning device designed for deep seawater pipes for which existing commercial devices and services were not economically feasible. The forward movement and rotation of brushes effectively remove attached marine life without causing damage to the pipe material and recover the water level of the intake structure from the trip level of 4600 mm to design level of 6000 mm in intake tank. 3D modeling using SolidWorks was used to assess the load distribution within the device and allowed for the calculation of individual loads on device elements based on their physical properties, thus resulting in the determination of the total load of 1450 kg in a manner similar to field weight measurements. The potential fatigue load relief in the brush body installation section on the shaft was calculated to be the maximum stress of 5.979e-03 N/mm2 ·MPa, that was lower than the maximum stress of 2.390e+01 N/mm2 ·MPa and the yield stress of 2.05e+02 N/mm2 ·MPa. It was achieved by reducing the weight of brushes and brush frames. The installation of brushes and brush frames resulted in maximum stress becoming concentrated, but the stress levels decreased after installation of the floater due to its effective load-lightening capability.