answering mess. 624.
Please, pinpoint what thread and date. Sofar I have found nothing of the sort. The only thing on my mind reminding of rings, is Kristijan's double ring "of fire", but that has nothing to do with your single ring on the nozzles;
Kristijan's rings are a part of the air distribution, your's is "behind" the blasting nozzles!
When time allows, look at the "balcony" stuff.