But by this time, the overall temperature of the pipe is so low that sag is considerably reduced or even eliminated. Laboratory tests have been completed, and the system now needs to be proven in the field. Diagram shows the difference in temperature profiles across the walls of pipes made with and without internal cooling. Measurements are taken 2 m down from the die. Parisi says the new cooling system should significantly improve the economics of production of thick-walled pipes.
Competitors join in.
Internal pipe cooling is high on the development agenda at numerous extrusion equipment makers around the world. Systems trialed use air- and, in some cases, water sprays. Confidentiality agreements with customers prevent several developers from providing information except for basic details, however. Cincinnati Milacron Austria, Vienna, may unveil its own system before the end of the year. Product manager Josef Dobrovsky says it is developing a product for pipes over 800 mm in diameter.