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Saturday 1st July 2006
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THINKING FOR PERFORMANCE TRENCHING IN HARD ROCK AND PERMAFROST
Any
operator of a conventional chain saw rock trencher is all
too aware of their machines inherent limitations in hard
rock, principally insufficient traction power for the digging
picks to adequately penetrate the rock, resulting in poor
productivity with high running costs and an uncomfortable
ride from the inevitable machine vibration. Until now! |
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British
trencher manufacturer Mastenbroek of Boston in Lincolnshire
has announced the introduction of a completely new
range of remotely operated hard rock trenchers featuring
a revolutionary method of cutting which is proving
to increase productivity with lower running cost.
Unlike
conventional trenchers where a rear mounted digging
boom is pulled onto the rock face, the Mastenbroek
fully patented “HRT” design has a reciprocating
boom with an endless reverse cutting chain that is
pushed into the bottom of the trench to create an
undercut. |
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The
cutting head is then progressively raised through the material
until it breaches the surface, at which point the boom is
then lowered and the cycle restarts to excavate the desired
depth and width. |
The
Worldwide trenching industries enthusiastic development
of heavier and more expensive trenchers in order to generate
sufficient pick penetration is, according to Mastenbroek,
made obsolete by the HRT technique. With conventional trenchers
the entire length of the digging chain is in contact with
the rock face; however the HRT only engages the lower part
of the cutting head. This results in a 125% increase in
transmitted power to the picks penetrating the rock face. |
The
HRT digging boom is located under the belly of the
machine, with the cutting head to the front. As the
boom is raised the resultant force locks the trencher
in place, ensuring that the full force of the digging
picks penetrate the rock face.
Spoil
is carried along the top of the digging chain, discharging
onto a rear conveyor to place the material to either
side of the trench.
Photo
shows the HRT 25 excavating trenches up to 2.5m (8ft
3in) deep and 650mm (26in) wide for installing water
and sewerage pipes in a new city development. Since
1999, on this same job site, the customer has been
operating a large rock trencher of 750hp, but as with
any trencher with the conventional rear mounted boom
method, it is limited when trying to efficiently cut
into rock with a compressive strength greater than
20,000 psi (138 mpa). |
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The
HRT 25 at only 335hp is at present trenching through solid
rock of up to 33,000 psi (228 mpa), and is soon to move
onto even harder material. The HRT trencher is more than
matching the larger conventional trencher for performance
and with a significant reduction in the consumption of wearing
parts and fuel.
The
HRT range covers trench depths of up to 5m (16ft 6in) and
widths of 2m (6ft 6in), suitable for oil and gas pipeline
installation in both hard rock and permafrost.
More
information from:
Christopher
Pett,
Mastenbroek Ltd.,
Boston,
Lincolnshire,
PE21 7JG ENGLAND.
Tel: 00 44 1205 311313
e-mail: christopher.pett@mastenbroek.com
website: www.mastenbroek.com |
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