For some years the shrink hoses to DIN 30672 [DIN30672-1a], also called shrink sleeves [Opitz85], that have proven themselves in the gas and water sectors have also been used in the sewage sectors for sealing pipe joints up to DN 1200 [FI-Raych].
Shrink hoses consist of jet soaked polyethylene with an inner coating of thermoplastic sealing adhesive.
Jet soaked plastics, especially when they are specially mixed with stabilisers, possess the following properties [Opitz85] :
The longitudinally split shrink sleeve suitable for repair work (Image 220.127.116.11.2-1), is laid around the previously cleaned and pre-warmed pipe joint to be sealed and closed with a suitable closing system - sealing clip or flexible rail of chrome-nickel steel.
Spiral formed sealing strips of plastics are placed around the respective pipe region for provisional sealing of the leaking pipe joint and also for filling of cavities during the installation.
During the heating of the socket with an open, soft propane gas flame, shrinking forces are released, which squeeze the permanently plastic seal adhesive into possible cavities and unevenness so that a fixed and leak tight pipe joint is created which, nevertheless permits angular changes and longitudinal movement.
The shrinking process has been properly executed when