This does not look right to me? the sink did drain with out any problems.
Did you run open or fill first?
Would like a broader view.
That the new “q” trap.
No that is just an idiot’s attempt to vent an island without knowing what they are doing.
Bob, I know what it is suppose to look like. And yes I drained it full of water.
From the picture I see no method of air displacement.
It reminds me of an air hammer arrester for a drain
You wacky newbies…lol
I guess save it for the weird file.
I think the only reason it drained is that the main drain is about a foot away in the basement where the sink drain hooks up and it has plenty of air
Put that setup on the other side of the house with a 25 ft path to the main waste stack through a 1.5" pipe and watch it drain and drain… and drain… then gurgle… and gurgle…