Waste collectors-how do they work?

[mr_alberta]

I've always been a bit confused as to how Waste collectors with the auto shutoff work on skimmers.

I know as the skimmate rises in the collector, it eventually causes a flapper or ping pong ball to seal an opening or something like that. So, does the air intake for the beckett hook up to this opening or something? Please enlighten me as to how these collectors work and how they can stop the air going into your skimmer.

Thanks.