This isn't new. It's a Thein Baffle, been around for ages I've built a couple. And they are included in many commercial designs.

It works as described above. negative pressure draws air and debris into the drum tangential to the side causing the flow to swirl around the circular chamber where the particles with higher mass fall to the outside through the slot. When you look in the bin after it's been used the large chips are all around the outside of the bin and the finer stuff near the middle.

As to the original problem, the issue I suspect will be that the cyclonic separator you have is simply not man enough for the job. The cyclone works on a similar principle of imparting angular momentum to the dust and the conic portion helps maintain the angular velocity of the vortex as the dust falls. It is VERY efficient. However the problem is that if the saturation of dust and chips in the incoming air is too high then there isn't enough energy in the vortex to throw it all outwards and you end up with dust being sucked through the centre because it can't be thrown against the side. You simply have too much dust going into too small a conic section.

You need to get the balance between pressure differential, hose diameters, rate of flow, and conic cros section in the sweet spot. Yours I think is simply way too small for the volume of dust.

A cyclonic separator is a much more efficient design than a Thein baffle and should be upwards of 99%. The thein baffle is just sooooooo much easier to make as it's basically a 2d plate not a smooth 3D conic section. Check you tube lots of wood workers make both. Traffic cones are useful for this but pretty small!

There's a whole science on chip and dust extraction, where chips and dust are not the same thing. One requires high volume low pressure extraction (HVLP) the other low volume high pressure (LVHP). Most shop vaccs are LVHP.

Axminster tools used to have a very good explanation of extraction differences and they sell extractors with both thein baffles and cyclone separators.

Hope that helps.