Sunday, October 2, 2011

Understanding How a Screening Bucket Is Used

Certain excavation jobs call for the use of a screening bucket attachment to the excavator arm. This is a particular type of excavator attachment that has the special property of being able to "screen" materials passing through it so that materials of a particular size or shape can be separated from the rest of the matter. There are a number of different excavation scenarios in which the use of a screening bucket is preferable.

In its design it does not look that dissimilar from an ordinary large sized digger bucket. The bulk of its frame is similarly laid out. The main bucket body has several teeth attachments and side blades. At the bottom or back of the bucket there is a space with four to five bars spanning the gap. These bars are attached to a motor that allows them to rotate, usually in either direction. These bars can be fitted with a variety of "blades". The type of blade that is used depends on the application of the bucket.

The blades on each of the rotors of the bucket move between each other, maintaining a gap that relates to the size of the material that is to be screened. A typical example of a use for a screening bucket would be in the separation of top soil from rubble. Where there has been deep excavations during landscaping a lot of dense and rocky soil will have been unearthed. Obviously large rocks cannot be used for producing topsoil so they need to be removed.

The bucket is then tilted so that the rotors are facing to the ground. As the rotors begin to turn the fine earth that will make up the topsoil passes between the blades. The larger rocks are passed from one blade to the next as the rotors spin them. Depending on the type of screening bucket the rocks may pass out through narrow channels in the side of the bucket or simply kept in the bucket until the fine earth has all been screened and then tipped out into a separate pile.

Other types of excavation that call for a screening bucket include the burying of underground pipes and cables. Heavy rocks and boulders excavated from the ditch the pipes or cables are to be laid in have to be screened. Heavy rocks could easily damage pipes or cabling underneath them. Their weight might be enough to crack or even crush a pipe or they could wear away a cable as the soil they are in settles.

Recycling is another area where screening buckets are commonly used. They can be used to separate recyclable materials from soil or to separate smaller recyclable materials from larger materials such as concrete. Some screening buckets can be fitted with special blades that can break up certain materials such as glass and soft timber for. These can then be melted down, used as fuel, pulped or used as wood chips. They are also often used to mix materials for industrial use such as in the production of bricks or cement.

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