Innovative concept for energy-efficient pipe production

At K 2010, the Infrastructure Division of battenfeld-cincinnati (Bad Oeynhausen/Vienna, Austria) will present for the first time its “Green Pipe”, a modular concept with three possibilities for substantially reducing the length and energy consumption of pipe extrusion lines: Efficient Air Cooling (EAC), the KryoS die and the innovative downstream solution requiring much less water.

image Through the use of a pipe die with Efficient Air Cooling (EAC), a 25 to 30% reduction of the cooling section can be achieved. This system, which can also be retrofitted, provides additional effective inside cooling of the pipe by means of an air current moving in the opposite direction to the extrusion process. The extrusion die is also selectively cooled by air currents. In this way, the melt temperature can already be reduced in the die. The result is very even cooling of the pipe, and deposits on the inner surface of the pipe are prevented. In conjunction with the distribution properties of the lattice basket die, even narrower dimensional tolerances can be reached, as well as corresponding material and energy savings.

image The length of the cooling section can be reduced by up to 45% if a KryoS die is used. This die is designed for optimal melt distribution based on spiral mandrel distributors. The melt is split up into several layers and cooled from the “inside” by means of a closed-loop tempering circuit between the layers. Thus, the “bottleneck” of heat conductivity especially in thick-walled pipes can be circumvented in a smart way. The melt temperature at the exit of the die is significantly reduced once more, compared to EAC. With the shorter length of the cooling section, pumping performance is also reduced, with the direct result of substantial energy savings. A smaller number of aggregates also cuts regular maintenance costs.

Finally, the energy consumption of the cooling section itself can be almost halved by using the new downstream equipment concept to be presented at the K for the first time. This trend-setting concept, financially subsidized by the Austrian Research Promotion Agency (FFG), was jointly developed by battenfeld-cincinnati, the Austrian processor Poloplast GmbH & Co. KG, Leonding and the Technical University, Vienna. During the testing phase of the new cooling concept on a Poloplast production line under normal production conditions, a significant cut in energy consumption was proved with simultaneous excellent pipe quality. This is due to the fact that not every tank has its own, direct cooling water inlet any longer, but the water only flows into the last tank and then on from one tank to the next in the opposite direction to extrusion. While in conventional extrusion lines with four cooling tanks a total of some 20,000 liters of cooling water per hour flows through the circuits, the new system requires only 2,500 liters per hour.

As a result of flowing from tank to tank, the water is heated up considerably by the time it reaches the first tank, but this is actually desired as an integral part of this solution. On the one hand a major part of water cooling can be effected by open air cooling, on the other hand, the waste heat could, for example, be utilized for a low-temperature heating system for the processing plant.

With its three Green Pipe solutions, battenfeld-cincinnati offers its customers an opportunity to reduce material, energy and water consumption and thus significantly increase the efficiency of their production processes.