Page 22 - Trenchless Technology Piping Installation and Inspection

New Dev e l o p m e n t s xxi

Metallic Restraint Casing

Standard
Rieber Gasket

Metallic Restraining Ring

FIGURE 4 New Bulldog Restraint Joint System for trenchless applications of PVC
pressure pipes. (Source: S & B Technical Products.)

are horizontal directional drilling (HDD) with pipe ramming, such
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®
as Conductor Barrel , Drill Stem Recovery, Bore Salvage , Pullback
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®
Assist , and Pipe Ram Rescue (see Fig. 5) for retrieving a disabled
MTBM, all offered by TT Technologies.
When HDD procedure reaches its limits—for example, on
extremely long crossings with large pipe diameters—the Herrenknecht
Pipe Thruster offers the necessary extra power. Installed at the target
pit, it pushes the pipe string with a thrust force of up to 750 tons
towards the entry point. Furthermore, it distributes the forces acting
on the pipe, since the pipe string is pulled (by the HDD rig) and
pushed (by the Pipe Thruster; see Fig. 6) at the same time. The pipe
string is handled with the specially developed clamping segments
which are suitable for pipe coatings and diameters of 20 to 60 in.
A further advantage of the Pipe Thruster is its mobility. It can be
installed in densely built-up areas and in inaccessible terrain.
Design engineers, utility owners, and contractors should consider
the existing and proven methods, and those viable methods that will

FIGURE 5 Pipe Ram Rescue. (Source: TT Technologies.)