PETpla.net Insider 07+08 / 2013

BOTTLE MAKING 22 PET planet insider Vol. 14 No. 07+08/13 www.petpla.net KHS claims compressed air savings of up to 40% with Airback Plus Air back Based on an article by Frank Haesendonckx, KHS Corpoplast KHS Corpoplast developed the Airback Plus system for the InnoPET Blomax Series IV stretch blow moulder. More compressed air from the stretch blow moulding process can now be reused than was previously the case, says KHS Corpoplast. The InnoPET Blomax Series IV cuts its use of compressed air by a targeted redesign of the valve block, among other factors. Depending on the bottle volume, between five and 15% of compressed air is saved, compared with the Series III. At the same time, the dead space volume (the volume of air which is applied at high pres- sure but which does not help to form the PET bottle) has been reduced by 25-30%. KHS Corpoplast claims that bottles can be manufactured from a pressure of 28bar upwards. Reuse of air A minimum of compressed air is consumed per bottle. A big target is to reuse as much of the air digested in the system as possible, again reducing the amount of compressed air required by the stretch blow moulder. Hitherto, KHS Corpoplast satisfied this market demand with its Airback I and Airback II systems. During the stretch blow mould- ing process the pre-blowing phase (PI phase), which takes place at low blowing pressure, is then followed by the blow moulding of the bottles at high pressure (PII phase), after which the pressure is then reduced. In Airback I some of the compressed air present in the newly produced bottle is fed into a ring line located at the centre of the blowing wheel. From there it passes directly to the next preform to be blown. The pre- blowing phase thus makes use of the existing compressed air. About 10% of the compressed air used for stretch blow moulding can be saved with Airback I alone. Airback II builds on the Airback I process by feeding more of the com- pressed air present in the finished bottle into a second ring line. This sends the compressed air through a rotary distributor out of the stretch blow moulder and straight into the compressor. It then uses its energy to prepare air for the PII phase, increas- ing the pressure from 28 to 40bar. Where Airback II is incorporated, up to 20% of the energy consumed during the process is saved. Reduction of compressed air Airback Plus no longer reduces the energy in the compressor but instead directly reduces compressed air con- sumption itself. The system works as follows: the reusable compressed air present at the end of the Airback I process in the newly produced bottle Airback Plus air reovery system by KHS Corpoplast: 40% internal high-pressure air recycling