Krah pipes are large polyolefin pipes up to an internal diameter of 4000 mm and a maximum solid wall thickness of 200 mm.
The preferred jointing technology is the butt fusion technology, however for low pressure rates the integrated electro fusion technology is also acceptable. Nearly any internal and external diameter within the
upper mentioned range can be produced, using the Krah spiral cross-winding extrusion process. Thanks to the unique pipe production machine developed by Krah, even the biggest pipe diameters can be produced on very little space (30 m x 30m). Therefore a most efficient use of this production machine on site is possible.
Krah pipes are produced according to the Krah spiral cross-winding extrusion process. During the production process the pipe is produced seamless and all sub-processes are continuously controlled by the integrated CPV and control visualizing software. The first layer is produced on a heated calibration mandrel, the next layers are produced cross-over accordingly on top of the previous layers. The previous layers are heated by an IR-Heating system to provide a surface temperature between 170°C and 200°C.
With the help of the co-extruder the inner surface can be produced with an inspection friendly, coloured polyolefin material. The orientation of the molecules is in radial direction, which has a positive effect on the internal pressure. Another important quality advantage is, that due to the slow cooling down process no frozen stresses will occur in the pipe wall.