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ALLU,
FINLAND
R
ecent developments and growing environmental
awareness have seen increasing numbers of pipeline
contractors taking advantage of some of the latest
technology on the market. In many cases the
contractors have utilised ALLU Transformer screeners and
screener-crushers to provide bedding and to cover the freshly
lowered pipe with fine soil. The soil used is the excavated
material from the pipelaying, with the impurities and rocks, etc.
being processed out, thereby ‘transforming’ it into fine soil ideal
for the filling in of the trench.
The ALLU Transformers are attached to the pipeliners’
excavators in place of the factory supplied bucket. They operate
hydraulically from the excavator’s own hydraulics in order to
separate soil from rock and debris. In doing this, several hundred
m
3
/d of soil spoils per excavator are able to be processed, as
they move along the pipeline track where the freshly laid pipe is
waiting to be covered with up to 600 mm of finely screened or
crushed soil. This soil is required to be laid underneath, around,
and on top of the pipe in the trench to prevent stones and
foreign debris from scratching or etching the pipe underground.
This could lead to leaking of any liquid being transported. This
helps to make the pipelaying process more efficient, and also
ensures that it is as environmentally friendly as possible, by
reusing excavated materials, and ensuring the pipe does not
contaminate the surrounding area.
In addition, there is no need for the contractors to
spend large amounts on buying in sand or top soil. As well
as sand being a valuable commodity, it is also becoming an
increasingly endangered naturally occurring material. If soil is
able to be reused in-situ, the
environmental benefits are
significant. It also means there is
no need to transport material from
large distances, which can endanger
workers and the environment alike.
The stones and rocks being excavated
from the trench are also an ideal source
of sub-base and aggregate.
Some contractors have been using the
combination of an ALLU D-Series Transformer
with TS®drum. Designed to be mounted on
12 t loaders, and 8 t tractors and backhoe loaders,
the ALLU Transformer D-Series is comprised of a
mounted attachment which screens, crushes, aerates,
blends, mixes, separates, feeds, and loads materials.
This results in the feed material being transformed into
valuable products.
The use of the fine-screening ALLU TS drum
construction when fitted with standard blades enables
material to be screened on-site, and then backfilled directly
into a trench. At the core of the TS drum construction is the
configuration of the screening blades that spin between the
screening combs. The end product size is defined by the space
between the combs, and different fragment sizes can be achieved
by repositioning the blades. As the screening combs carry most
of the material weight, the drums and bearings experience less
impact and load, with the design of the assembly ensuring the
machine works well in wet and dry materials without clogging.
In one recent example a major pipeline contractor
achieved savings in excess of 80% per m
3
using an ALLU
Transformer D-Series attachment with TS drum assembly –
specifically a DH 3-12 TS16 – fitted to a standard excavator.
The US based contractor found that traditional screening
provided low productivity and proved inefficient, as
large soil particles and stones were often getting into
the trench. The traditional option in this situation
available to pipelaying contractors has been to
buy in soil or sand. However, the high cost of
soil made this an unattractive option. After
switching to an ALLU Transformer with TS
drum construction, the contractor found
that they were achieving high rates of
productivity and their costs were
significantly lower.
TS blades are available in two
different types: standard blades
for screening applications, and
axe blades when a crushing or
shredding effect is required.
Blade sizes that are available
include 16 - 32 mm,
25 - 50 mm and 35 mm.
ALLU D series at pipeline jobsite.
ALLU D series working at pipeline jobsite in Ireland.
Heavy equipment review
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