Addex Presented a New Single-Inlet Plenumfor Retrofitted Blown Film Line

Addex Inc., an original equipment manufacturer of high-performance blown film cooling equipment, introduced a single-inlet plenum (patent pending) as a retrofit to existing blown film lines at the NPE 2024 exhibition in Orlando, Fla.

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 into multiple, closely-spaced inlets with corresponding improvements in gauge control.

In response to customer demand, Addex has designed a single-inlet plenum with the performance of a multi-inlet plenum. The company’s new aerodynamic design (patent pending) 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 aren’t seen in the film which is a major step forward in single-inlet plenum design.

Other advantages of a single-inlet plenum include a reduction in hoses (which can total eight or more) down to a single hose. This saves space on the plant floor, providing easier access around the die for maintenance and operation, and completely eliminates the common problem of multiple hoses having variable lengths and bends leading to negative effects on the finished thickness profile (even when used in combination with automatic profile controls).

Addex also employs this new single-inlet plenum design in combination with its high-performance auto-profile External Gauge Control (EGC) system, providing an improved starting point (before control) and better end results.

“Running the new single-inlet plenum together with our EGC was a big shock—normally on our pilot line, we have an expected starting point of profile variability (using a multi-inlet plenum), and we see a noticeable decrease with the new single-inlet plenum,” said Gautam Jagannathan, Addex’s Software Specialist and Senior Field Service Engineer. “This means the EGC has less work to do since there is less to correct. As an added bonus, we have hints that even bubble stability is improved, which we currently attribute to the removal of multiple mixing points found in conventional plenums.”

With an improved single-inlet plenum option, Addex foresees strong demand from many producers looking to make the switch for retrofits. Overall, processors are attracted to the upgraded single-inlet design because it outperforms the multi-inlet plenum in terms of profile control and the single blower hose allows for easier access to the die.