Buderus Manual on Trenchless Installation of Ductile Cast ... - Duktus

joints is DVGW Arbeitsblatt GW 3 8 of
June 2002 [2. ]. The current designs are
shown in section in this document together
with the associated performance data.
A distinction is made between joints which
are locked by friction and joints which are
positively locked. With its BRS ® frictionlocking
joint and its BLS ® positive-locking
joint, <strong>Buderus</strong> offers two innovative solutions
in this case. In the BRS ® frictionlocking
joint (Fig. 2.17), sharp, hardened
stainless steel teeth bite into the surface
of the inserting end and this produces
the frictional connection. There are also
friction-locking designs for bolted-gland
socket joints.
In the BLS ® positive-locking joint, a bead
of weld metal is applied to the surface of
the inserting end either in the factory or
on site and appropriate force-transmitting
members are supported against this
bead and thus transmit the longitudinal
force from one pipe to the next (Fig.2.18).
Fig. 2.17
Fig. 2.18
Entwicklung der Verbindungstechnik
The development of these socket joints, which are locked against longitudinal forces
but at the same time able to hinge, to their present-day standard of maturity was essential
to the development of modern-day trenchless techniques for installing pressure
pipelines. In almost all of the trenchless installation and renovation techniques which
are described in the present manual, it is a hinged string of pipes locked against longitudinal
forces which is pulled into the final route of the pipeline. Whereas in the series
of standards which applied previously, namely DIN 28 00 et seq., it was just the pipes
and fittings which were exactly described, in the European standards which now apply,
namely DIN EN for water pipes and DIN EN 9 for sewage conduits and pipes,
there is a new aspect which is considered, namely the functional requirements they
have to meet. With their exact descriptive specifications, the earlier national standards
provided what was needed for technical delivery conditions. The additional aspect
dealt with by the European standards, namely the functional requirements which the
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