Centrifugally Cast GRP Pipes

The HOBAS Centrifugal Casting Process is a fully automated production process. A computer program controls the feeder arm, which continuously inserts the three basic components, glass fiber (GF), unsaturated polyester resin (UP) and aggregates, into the over 6-meter-long rotating mold. This is how the pipe is produced layer by layer – see details on the right. 

Depending on the required pipe properties, stiffness and pressure class, the production uses a certain algorithm that produces a standardized wall structure conforming to DIN 16869 with accurate defined wall structure layers. The high pressure loads during the casting process reaching 30 to 70 bar ensure complete compaction and that no air remains entrapped.

Result: A void-free and gas-tight pipe wall. The total absence of voids in particular is very important for the quality of GRP products. Despite the fact that we can produce a virtually unlimited number of pipe types, HOBAS Pipes always have a characteristic wall structure. A core layer made of aggregates and resin is enclosed between two highly reinforced layers consisting of glass fiber and resin. The transitions between the individual layers are smooth as the mixing ratio of the various materials changes. This structure is basically the same as that of a double T-beam, which means high load capacity combined with economical material use. On the outside there is a resin-rich, UV-resistant, sand-filled layer, while the pipe is finished with a resin-rich inner layer on the inside.

Centrifugally cast HOBAS Pipes have been installed in many projects. Find HERE the latest references.