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26
Tube Products International January 2016
www.read-tpi.comproducts & developments
Record size microtunnelling
with Hobas CC-GRP pipes
In the Polish capital Warsaw, a
3.2km-long Hobas De 3270 pipeline
has been microtunnelled on the left
bank of the Vistula River to transport
sewage and rainwater from the central
and northern districts to the wastewater
treatment plant (WWTP) Czajka.
The new line will discharge the old
Burakowski sewer, and represents an
extension of the De 3000 jacking project
that earned Hobas the ISTT No-Dig
Award in 2011. Within almost eleven
months, a new interceptor sewer has
been installed via microtunneling along
Marymoncka Street in Warsaw.
Built from Hobas pipes with an outside
diameter of 3,270mm, it is claimed to
be the largest-diameter microtunnelling
project to be implemented with CC-GRP
pipes in Europe so far.
The Burakowski-Bis interceptor com-
pletes the sewer system leading from
the left-bank Warsaw area to the WWTP
Czajka located on the right bank of the
Vistula River.
Due to its limited capacity, the over
50-year-old Burakowski sewer could
no longer handle the large amounts
of combined wastewater during heavy
rains. Its poor operating conditions
posed a threat to the entire sewer
system and regularly led to emergency
discharges of untreated wastewater
into the Vistula, causing an ecological
hazard. The construction of a new
parallel sewer with additional retention
capacity should allow for a higher level
of environmental protection.
The new sewer should also transport
wastewater to the WWTP Czajka and
make it possible to discharge and
modernise the old sewer. Microtunneling
was chosen as the optimal method for
the construction of the Burakowski-
Bis sewer for several reasons. The
dense urban environment meant that
the new line had to be installed at a
depth of 8 to 13m underneath the
green belt separating the two lanes of
Marymoncka Street. There was also a
tram line running close by, as well as
underground technical infrastructure.
It was recognised that trenchless
installation would considerably reduce
excavation works and traffic disruption,
as well as shortening the construction
time of the new sewer line. Only a short,
47m-long section of the project was
realised in open cut, on a green space
alongside Słowackiego Street.
The total length of the microtunnelled
sewer line is 3,204m, and it consists
of seven segments ranging in length
from 107 to 613m. The first, and
most demanding, section led from the
launch pit at Dorycka Street to the
receiving pit at the Maria Skłodowska-
Curie Bridge. It had a length of 410m
and included a 97m-long curve
with a radius of 400m, which was
implemented with 1m-long pipes.
Due to the good lubrication and high-
performance properties of Hobas pipes,
the section could be realised without
difficulty, with a maximum jacking force
of less than 600 tonnes. The intermediate
jacking station originally designed for
this section was not needed, which
made the assumed work progress of
10m/day increase to 16m/per day.
Hobas Engineering GmbH
– Austria
info@hobas.com www.hobas.comPrecision ball valve
with greater flow
When Beswick introduced its 10-32
threaded ultra-miniature ball valves,
the MBVMD-1010-303 ball valve won
Design News Magazine
’s Best New
Product Award in 2011.
The MBVMD-1010-303 is suitable
for many miniature, high-technology-
type applications. However, when
an application requires a precision
ball valve that is more compact than
traditional NPT threaded ball valves,
but that can also provide more flow
than is possible with 10-32 threads
and a relatively small orifice, that
configuration is not always easy to find.
The Beswick MBV-1414-3 ball valve
is designed with 1/4-28 UNF straight
threads and a relatively large orifice
diameter of 0.125", and weighs only
34g. It provides more than three
times as much flow area as the 10-32
threaded valve.
Beswick Engineering Co, Inc
– USA
besales@beswick.com www.beswick.com