Extrusion International 3-2021

31 Extrusion International 3/2021 RECYCLING “This level of reuse can still be signi fi - cantly increased thanks to the high quality of the recycled pellets,” says Manfred Dobersberger, Managing Director of PURE LOOP. “The high de- mands on the recycling process result from the high volume of the bulky input material as well as the material composition of the drip tapes and ir- rigation pipes,” he explains. Their job is to ensure that crops can grow and thrive, using as little water, fertiliser and pesticides as possible. For this purpose, either thin-walled HDPE drip tapes laid on the surface or HDPE irri- gation pipes buried in the ground are used. Thewater is distributed through emitters. In the case of the thin- walled drip tapes (150 to 250 μ m), these are LLDPE injection-moulded parts which are spaced at regular in- tervals of around 20 cm. In the case rial or complete rolls with drip tapes. Single-shaft shredders and double feed ram systems fl exibly adapt to individual logistic requirements and, thanks to the conical transition to the extruder, the material is compacted and oxygen is reduced, which ensures the plastic material is processed very gently. The entire ISEC evo series also offers straightforward operation and a high degree of automation, and the machines are quickly ready to start processing at any time. This overall recycling concept has al- ready impressed irrigation system producers in the USA, Israel, Italy and Mexico. They operate recycling plants with throughputs of 100 to 500 kg/h and reuse the recycled pellets pro- duced in proportions of up to 20 per- cent in the production process of thin- walled tapes and thick-walled pipes. However, practical tests have shown that signi fi cantly higher proportions of recycled pellets would be possible in the end product. “Even for very thin drip tapes with a wall thickness of 100 μ m, we were able to use a pro- portion of 10 percent recycled pellets in a 48-hour trial without any loss of quality,” says Manfred Dobersberger. of thick-walled irrigation tubes (over 300 μ m), the emitters are also fi tted with a siliconemembrane for pressure compensation, so that the same fl ow rate of water is discharged from each emitter over the entire length of the tube and the fl ow of water is not ob- structed by soil, sand or roots growing into the emitter. Ef fi cient shredder-extruder combination for gentle processing The purpose-speci fi c function of the pipes and tapes is tested at regular in- tervals during the production process. “In order to test whether their irriga- tion pipes meet the strict quality stan- dards of a maximum of two pinholes per 10 kilometres, one of our cus- tomers pressure-tests them with wa- ter,” reports Manfred Dobesberger. “The proportion of foreign polymers in this material is a real challenge in recycling, but one that our ISEC evo shredder-extruder combination with doubledegassingand EREMA laser fi l- ter can handle with perfectly”. In the laser fi lter, three scrapers rapidly and continuously remove contaminants – which mainly consist of the silicone in the emitters – from the fi lter screen during each revolution. The ef fi ciency of this fi lter enables high throughput rates in the recycling process and the highest recycled pellet quality. Fur- ther advantages for the user are that, as an all-rounder, the recycling ma- chine processes bulky hose bundles as well as other production waste such as start-up lumps and regrind mate- The Best Recycled Pellets for Irrigation Pipes Manfred Dobersberger, Managing Director PURE LOOP, andMerlijn van Essen, Sales Manager PURE LOOP (Photos: PURE LOOP) The shredder-extruder combination from recycling technology provider PURE LOOP is an ideal solution for recycling challenging production waste. This category includes drip tapes and irrigation pipes that accumulate as waste during the production of irrigation systems or are rejected during quality inspection. Manufacturers who already implement this technology reuse production waste in the formof recycled pellets in proportions of up to 20 percent - without any loss of quality compared to production from virginmaterial PURE LOOP GesmbH Unterfeldstr. 3, 4052 Ansfelden, Austria www.pureloop.at As an all-rounder, the ISEC evomachine processes bulky hose bundles as well as start- up lumps and complete rolls with drip tapes