Page 91 - Trenchless Technology Piping Installation and Inspection

58 Cha pte r T w o

FIGURE 2.5 CIPP installation process. (Source: Insituform Technologies.)

Winch Pulling-in excavation for Heating element
two-sided pulling-in butt-welding machine

Guiding roll
Pulling head Roller
with cable block

Pipe to be rehabilitated Welded plastics continuous pipe
FIGURE 2.6 Schematic diagram for conventional sliplining process with annular
space. (Stein, 2001.)

The spiral wound process uses a layered composite PVC liner and
cementitious grout to renew both worker or non-worker entry into
the existing pipes. The combination of the ribbed profile on the PVC
liner and the highly fluid nature of the grout produce a highly inte-
grated structure with the PVC liner “tied” to the existing pipe through
the grout. The structural strength of the renewed pipe is determined
by the grout characteristics. Figure 2.8 presents a schematic of a spiral
wound process.

2.3.4 Coatings and Linings
The spraying of a thin cemnet-mortar or a polymer coating on the
internal surface of existing pipe is another method of pipeline renewal.