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26

Tube Products International January 2016

www.read-tpi.com

products & 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.com

Precision 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