Boring - Trenchless International

projetcs
April 2010 - Trenchless International
Green machine
saves the day
In the Polish city of Kielce a HDD rig, featuring second
generation ADBS and a new type of backreamer, has
successfully completed a crossing in sandy clay
ground conditions.
The project involved a 76 metre
length of HDPE pipe OD 160 mm installed
using horizontal directional drilling (HDD)
to leave a busy, central area undisturbed.
Kielce-based project contractor Ekobox
Sp. z.o.o. specialises in installations of
telecom power lines and road lighting,
using trenchless pipe and cable laying
The TERRA-JET 4015 S during the
pilot bore.
techniques. The company has a history working with piercing
tools and has recently complemented their fleet with the addition
of the HDD machine; TERRA-JET (TJ) 4015 S.
Ekobox owner Mr Suchansky selected the premium TJ
model, which is equipped with an air conditioned driver’s
cabin, an MP3 player and an on-board computer with touch
screen. The width of the operator’s cab allows the seat to
rotate 180 degrees. Manufacturer TERRA AG says that the
computer saves every metre of the bore as it prints out a bore
protocol with all torques, pulling and thrust forces, and also the
drilling fluid volume and pressures. The touch screen gives all
the information the operator requires, says the company.
The drill operator drives and operates the HDD machine using
two multifunctional joysticks installed in the left and right armrests
of the operator’s seat, allowing control and smooth movement of
the rig.
The TERRA-JET 4015 S can drill directional bores up to
200 metres length and 460 mm diameter, depending on ground
conditions. It is driven by a 62.5 kW (85 HP) powered diesel
engine, which is ‘clean’ and fulfils the required ‘green’ emission
regulations for some years to come.
Torque and pullback force are produced by separated
hydraulic circuits allowing the maximum torque of 4,000 Nm
(3,000 ft.lbs) and the maximum pullback force of 150 kN
(15 tonnes, 33,000 lbs) to be used simultaneously under full load.
The drilling fluid volume is 90 litres per minute (23 gpm) at
a maximum fluid pressure of 70 bars (1,000 psi). The drilling
The HDPE pipe OD 160 mm is pulled in.
The new 215 mm TERRA back reamer
with tungsten carbide teeth.
fluid volume may be optionally increased. The system which
mixes the bentonite into the drilling fluid via an injector (Venturi
hopper) is on board the HDD machine. This patent removes the
need for an extra mixing system and a second engine.
The TERRA-JET 4015 S is equipped with a second generation
Automatic Drilling and Backreaming System (ADBS). This patented
ADBS automatically and within milliseconds adjusts the
working speed of the drill to suit the ground conditions says the
company. In soft ground the drill operates at maximum speed, in
hard ground slowly, but always at the optimum speed.
Machinery in action
The 76 metre long pilot bore in the sandy clay was achieved
with ease. The drill head could even be located underneath the
reinforced concrete plates. Said the contractor.
After the pilot bore the drill head was replaced by a new back
reamer 215 mm. TERRA has developed this new type of backreamer
with tungsten carbide teeth, which can be replaced easily
every time. This new backreamer has an integrated protection
pipe for the swivel, which closes the space between the backreamer
and the HDPE pipe. Therefore preventing stones from
falling in front of the expander chuck and block the backreaming.
With the backreamer the HDPE pipe OD 160 mm (6.3 inch) was
pulled in simultaneously, proving no problem for the rig.
Mr Suchansky said “The new design and concept makes
the TERRA-JET Series S to one of the most productive HDD
machines available.”
Coating shafts –
substrate preparation perfected
by Rainer Hermes
For an effective and long-lasting – and hence economical – shaft coating, careful and thorough cleaning and
preparation of the substrate is essential.
Hermes Technologie, based in Schwerte, Germany,
has been successfully developing coating procedures using
ERGELIT dry mortars for over 20 years, launching the KS-ASS
(M-Coating) process on the market in the late 1990s, and very
quickly complementing it with an automated shaft cleaning rig.
Named the TSSR, this is an array of high pressure cleaning nozzles
which form part of the M-Coating equipment and are raised
and lowered in the shaft mechanically, to achieve thorough
preparation of the substrate.
Continuous market observation and monitoring of client reaction
led to a ‘high speed’ version of the TSSR at the end of 2006.
The company said that at 380 bar and 24 litres per minute and
with a completely new design of rotary nozzles, shaft cleaning
equipment was now developed almost to perfection. Almost –
there were still some questions to answer.
How to treat hard clinker brick surfaces, new concrete shafts
or synthetic coatings before coating with ERGELIT? Intensive
research and experimentation finally led to the conclusion that
only sand-blasting could provide a satisfactory solution. But how?
By exposing operatives to conditions in the shaft?
Anyone who has ever seen such an operating procedure can
understand this would ran counter to the thinking behind the
M-Coating process of which the TSSR was an integral part. When
developing the M-Coating process, the Hermes team has given
the same priority to protecting the workforce as to improving
performance when it came to shaft rehabilitation. The M-Coating
name became virtually synonymous with fast, effective and top
quality shaft coating with ERGELIT. This was and still is the
reason why this, and only this, process has received the Berlin
DiBT’s certificate for coating wastewater collectors and inspection
shafts.
In the autumn of 2009, the Hermes team’s technicians and
engineers found the solution to the sand-blasting problem: developing
the TSSR into the HDS jet equipped with a combination of
water- and sand-blasting technology. The new process amazed
the professionals at the ENTSORGA show in 2009.
This apparatus, registered with the German patent office
under the name HDS-jet, is equipped with two water/sand
blasting nozzles. Operation is as the TSSR. The array rotates
through 360 degrees on its own axis and is raised and lowered
by winch. Working on the venturi principle, the high pressure
water pump creates a strong vacuum which in turn draws the
blasting sand out of the container.
The sand is then accelerated so powerfully through the nozzle
that it keys or prepares tiles, new concrete surfaces or synthetic
surfaces so that the new ERGELIT coating makes a permanent
bond. Thanks to the short, uniform and easily adjustable distance
between the nozzle and the shaft wall, the blasting sand, with
carefully selected grain size, gives very even results.
The speed at which the HDS jet cleans is around 15 minutes
per metre. That is, it normally takes one hour to complete the
cleaning and preparation of a standard four metre deep shaft
with these problematic shaft walls. In exceptional cases the
procedure can be repeated several times, depending on the
sandblasting finish required.
There is no need to send operatives into the shafts, which is
particularly important where these are narrow or difficult. Often
it is only the M-Coating procedure that can cope with major
projects – for example, a 25 metre deep shaft in London could
not have been renovated without this technique. As is the case
with the usual TSSR cleaning, the specialist operatives stand at
the top of the shaft and monitor the cleaning process or top up
the blasting sand if required.
The new water/sandblasting equipment is proposed as a
complete kit, or as an add-on to the M-Coating equipment. As
usual, the HERMES Technologie team will demonstrate the HDS
jet and explain the operational method and particular technical
and economical features on the spot. Poorly cleaned substrates,
however bad they originally were, should now be a thing of the
past. The economic problems of coating breaking off because of
inadequate substrate preparation can now be avoided. The technology
is available and simply needs to be applied. For clients
already using M-Coating, this is simply an important addition to
existing technology. HERMES Technologie ensures a powerful
bond and a highly durable coating.
pipe cleaning
April 2010 - Trenchless International
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