vacuum plenum

[Dan Hintz]

Airflow travels better in a straight line. If all the supports are round then I would think there would be more turbulence. Not that you would be able to detect it under the spoil board but when you open the valve to hold your material, IMHO, the initial flood of air being evacuated would be quicker with straight lines rather than round.

Yes, airflow is better in a straight line, but to keep it that way you don't want abrupt changes in direction... sharp corners are about as abrupt as you can get, so round is always better. Bat once the vacuum has been pulled, the airflow is so slow it won't make a difference... not that it ever made a difference in the first place.

If you wanted to get fancy schmancy, you would create teardrop shapes that pointed (round side) towards from the vacuum intake.

[Joey Jarrard]

Ed this is a pic from Paul S. the CAMaster owner who designed the top. This is a pic of his first prototype so it does have some slight changes.

If you can see there is a foam gasket along the edge of the stacked part. You push the spoil board up against it and turn on it will create a seal to the board. The final top also has the gasket around the edge of the zone. Please see pics Jim posted.

[Dennis OBrien]

And that board in the background could be the board you are routing? And a simular sized piece of peg board in between them would be a spoil board?

[Joey Jarrard]

And that board in the background could be the board you are routing? And a simular sized piece of peg board in between them would be a spoil board?

Yep thats correct

[Chuck Gallup]

Yes, airflow is better in a straight line, but to keep it that way you don't want abrupt changes in direction... sharp corners are about as abrupt as you can get, so round is always better. But once the vacuum has been pulled, the airflow is so slow it won't make a difference... not that it ever made a difference in the first place.

If you wanted to get fancy schmancy, you would create teardrop shapes that pointed (round side) towards from the vacuum intake.

LOL...You've hit all my hot buttons.

I was involved in deep sea cable trenching using high pressure sea water to cut trenches in the sea floor.
There is a calculation for fluid traveling across a 90º bend or orifice.
The loss is huge.
We used large spaces behind the orifice to keep losses down.

We used vacuum to pull an 18" column of water up a pipe about 7' to start a 1200 HP centrifugal pump. Used a regular shop vac to speed things up but a zero vac to get the grunt.

In hydraulics, there are systems that vacillate between series and parallel to speed up operations and then provide grunt when needed.
I haven't seen this idea applied to vacuum systems. Anybody else?


Somebody mentioned flat pyramids. What do you think the point loading on a truncated pyramids with 1/4" flats on a 4 x 8 table would be?
No problemo.