Instrumentation for Clamshell Buckets

Category:

Dredge Plant

Description:

Accurate bucket positioning is required when dredging contaminated bottom materials. The

Cable Arm environmental bucket combines an acoustic echo ranging device and a pressure

transducer, both attached to the bucket, to accurately position the bucket on the bottom. Vertical

positioning instrumentation has been used on sites in the Great Lakes. The system is site-specific.

Individual project site assessment, bottom profile, core sampling, water quality, and pre-survey

data will be used to design the control system of the clamshell bucket. The acoustic sensors are

reliable and can maintain calibration when subjected to noise, vibration, and turbidity.

The control system may be impacted by barge movements, and the lowering speed at the

beginning of the clam cycle. The critical sensing target area is approximately 3 meters from the

bottom, where the clamshell will pause for final sensing input. Limited horizontal movement will

not interfere with the final depth average. The ability to store depth and operational data will

provide valuable information to ensure that tight-tolerance dredging projects are performed

successfully, both economically and environmentally.

Reviewer:

J. Lally

Company / Organization(s):

Information Sources:

Literature:

Title:

"Instrumentation for Clamshell Buckets (Environmental Dredging)"

Author:

John Lajeunesse

Month:

Year:

1995

LitType:

Report/Proceedings

Publisher:

WEDA 16

Page:

Chapter 5 Other Technologies Reviewed