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

Shrink-on devices and protective
tapes
As an alternative to the cement mortar
protecting sleeve, the joint region can
also be protected with shrink-on devices
or protective tapes. The shrink-on device
must be suitable for the dimensions of the
particular joint involved.
Applying a shrink-on collar
The shrink-on collar has to be pulled over
the socket end before the joint is made.
The surface to be enclosed has to be prepared
in accordance with DVGW Merkblatt
GW 1 , i.e. the region has to be
freed of rust, grease, dirt and loose particles.
The surface must be pre-heated to
approx. 0°C with a propane gas flame set
to a soft setting and thus dried.
The shrink-on collar is then pulled over the
joint until it is central on it and the protective
backing on the inside is then removed.
At the point where the end-face of the
socket is situated, the shrink-on collar is
then heated evenly, all round, with a propane
gas flame set to a soft setting until
the shrinking process begins and the sleeve
starts to assume the outline shape of the
socket. Then, while keeping the temperature
even, which should be done by
moving the burner in the circumferential
direction while fanning it from side to side,
the part of the collar around the socket is
first shrunk on, and then, starting from the
end-face of the socket, the part around the
main body of the pipe.
~ 100
ZMU
123