Heyl & Patterson Blog

Continuous Barge Unloaders: The ABCs of CBUs

Posted by H&P Blog on Wed, Aug 03, 2011 @ 11:14 AM

Continuous Barge UnloaderHeyl & Patterson pioneered the design for the Continuous Barge Unloader, which has been a staple solution for handling bulk materials on waterways.  These machines have solved a variety of unloading problems for many customers demanding reliable, safe and versatile systems.  Diverse cargos such as coal, iron ore, bauxite, alumina, corn, wheat, soybean, agricultural by-products, wood chips and limestone have been successfully offloaded by Heyl & Patterson.

A Continuous Barge Unloader, or CBU, is a series of buckets supported between two strands of roller chain running in a continuous loop.  This structure is known as a digging head assembly.  The buckets are filled as they are dragged through the material in the barge, and are emptied as they pass over a discharge sprocket.  The continuous bucket unloader for river barges usually has a moderate to high capacity.  A moderate-capacity continuous bucket unloaders has a maximum free digging rate of 1500 tons per hour.  For a complete barge, including barge positioning and cleanup, the average unloading rate is about 65% of the free digging rate, or 950-1000 tons per hour.

The Continuous Barge Unloader is normally a stationary machine.  The structure includes a support tower with a fixed or moveable cantilevered boom, depending on how water levels fluctuate on the river.  The boom supports the digging head assembly and a transfer conveyor.  If the boom is fixed, the digging head assembly pivots to change the height of the digging buckets.

Continuous Barge Unloader ArmThe barge is commonly unloaded by a two-pass operation.  On the first pass, the digging head carves a trough down the center of the barge as it passes beneath the unloader.  On the second pass, the digging head oscillates back and forth across the width of the barge to unload any remaining bulk material.  A three-pass operation can also be used, in which the digging head is positioned on one side of the barge for its second pass and on the other side for its third.  The barge returns to the starting position between each pass.  A loose catenary at the bottom of the bucket chain loop allows the buckets to contact the bottom of the barge without damaging either one.

The Barge Haul System for a CBU employs a steel cable and hoist assembly that is permanently attached to the dock.  The Barge Haul System provides continuous smooth movement of the barge during unloading.  To reduce barge hookup time, a second barge can be attached to the trailing end of the first barge while it is being unloaded.  Barges are positioned into the Barge Haul System by a tugboat operated by power plant personnel.

In addition to engineering new CBUs, Heyl & Patterson can retrofit an existing unloader with upgrades, no matter who originally manufactured it.  Our newest upgrades elevate performance and efficiency levels by incorporating integral electrical and mechanical advancements.

Mechanically, Heyl & Patterson has refined a host of key operating elements to significantly enhance wear life and decrease down time.  Electrically, our improvements limit the need for maintenance, provide greater performance output and smoother operation, and prolong service life.

To learn more about Heyl & Patterson Continuous Barge Unloaders and the upgrades Heyl & Patterson can provide,

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Tags: bulk material handling equipment, barge unloaders, coal handling, ship unloaders