Challenge

An electropolishing process used an acid solution at approximately -60C. Ice was building  at the top of the vessel and, when it fell into the solution, the entire product batch and the acid solution had to be discarded.

Engineering Approach

A protective nitrogen-flow curtain concept was conceived to prevent ambient air reaching the vessel opening. A circular PTFE slot system was designed to generate the required flow pattern with CFD analysis used to refine and the design prior to prototyping.

Outcome

The design was prototyped and experimentally tested, demonstrating that no ice or condensation was generated. This solution eliminated the associated loss of product and acid solution and was subsequently implemented in production.