Connecting of the Flexible Ducting : Flexible ventilation ducting can be connected in different ways.
Steel Coupling
A steel ring is welded in one end of each tube. The tubes are then connected to each other by mounting the tube end without steel ring over the tube with steel ring. Then a steel connecting ring is mounted over the two tubes and tightened.
A connection system with one inner steel ring a lose tube end gives flexibility and different tube length can be connected to each other.
Zip Connection
Zip connection has been used since the beginning of the eighties. Today it is the most common connection. It is both the most strong and easy way of connection. It's is used when having long tubes and for large diameters. Zip connection is often used in TBM projects. The zip is mounted on the tube in both ends and is easily connected to the next tube.
Velcro Coupling
The Velcro connection can be used for larger diameter to make handling and connecting easier. The Velcro connection is mounted on the tube in both ends and is easily connected to the next tube. It is strong and will not be damaged and can be used for many years.