Munich, April 07, 2006. Krauss-Maffei supplied a Russian customer with a PU metering system with performance far beyond the range of conventional systems. Capable of output around 6.6 kg/s, the machine sets a new record in PU processing.
The machine is part of a system producing pipe for district heating networks. Pipe sections are up to 12 m long, with the diameter of the outer layer up to 1200 mm. Discharged into the space between the inner steel pipe and the PE outer layer, the reactive PU system foams up completely filling this space The PU foam with its outstanding insulation properties efficiently reduces heat loss in the heat distribution network.
Applying foam insulation effectively in pipe of this size, requires a PU machine capable of delivering extremely high output. Krauss-Maffei designed a machine with three pumps: two pumps for the isocyanate component and one for the polyol. In this application, polyol and isocyanate are mixed 100:150.
A four-component MKE-28-4/44 mixing head ensures homogenous mixing, with the isocyanate entering the mixing chamber through three nozzles. The system is engineered to minimize pressure losses, so that mixing performance is excellent even with very high throughput. The compact mixing head is easy to manipulate - an important factor in effective, errorproof system operation.
One machine for all pipe dimensions.
Despite the very high maximum output, the machine can also be used to produce smaller pipe dimensions. The pole-changing pump drives can operate at half speed; for shot weights of around 2 kg. This feature makes it possible to produce foam-in-place insulation for a wide range of pipe dimensions on one and the same system.
Currently the main markets for district heating pipe are Eastern Europe, Russia and China. There are more applications for pipe with a PU insulation layer, for example in oil and gas pipelines, refrigeration systems and snow-cannon systems.
Krauss-Maffei's new PU foam production system is capable of insulating heating pipe with diameters up to 1200 mm. PU insulation efficiently minimizes heat losses in the distribution network.