BLOWN FILM DIES | MACHINERY


Blown away: latest in blown film dies


Advances in blown film dies – and related equipment – include a system that adds additional cooling above the frost line and a new design of single-inlet plenum


Well-designed dies help to ensure that blown film lines make film quickly and accurately. However, maximising film quality also requires other factors – especially efficient cooling – meaning that ancillary products such as air rings are vital to efficient film production. Addex has developed a single-inlet plenum as a


retrofit to existing blown film lines. Historically, single-inlet plenums have featured only one blower hose, which facilitates an easier installation and creates space around the die. However, they have the reputation of being unable to deliver an even gauge profile. As a result, multi-inlet air rings have typically outperformed single-inlet plenums because they divide air flow


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into multiple, closely spaced inlets with corre- sponding improvements in gauge control. In response, Addex has designed a single-inlet plenum with the performance of a multi-inlet plenum. The aerodynamic design employs dual counterflow channels which direct air flow in two opposing directions inside the plenum. These two counterflows of air join inwardly together to create a combined uniform flow of air to the lip set. The measured overall profile performance is better than with a conventional multi-inlet air ring and inlet effects are not seen in the film which is a major step forward in single-inlet plenum design. Another advantage of a single-inlet plenum is a reduction in hoses – from as many as eight, down


Main image: Addex has devised a single-inlet plenum as a retrofit to existing blown film lines


June 2024 | FILM & SHEET EXTRUSION 33


IMAGE: ADDEX


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