Thread: Dust extraction

Obviously the bigger the CFM rating the better the suction will be, but the 1200CFM dusty would be a good start. One thing you need to consider is if you have a 3hp sawbench will your power circuit handle another 2hp motor at the same time?

Oh and welcome too!

2 HP 1200 will do the job. Don't get anything less.

There's lots of info on dust extraction on this site. Type 'dust extraction' into the search bar and you'll be reading for weeks.

What WB said... including the welcome.

A couple of minor points:

1. The thicknesser & jointer will probably put more demand on your DC than the TS... they produce thicker, heavier shavings while the TS should only produce dust. (Or smoke at the worst of times. )

2. With a mobile system hooked to two machines I'd still put gates in so that only one machine's vac'ed at a time... it means less suction is needed for the same functionality.

Thanks guys !

(I'm always a little surprised when things like 'posts' work ... something to do with a lack of trust in technology !)

I did do a search but I'll do another. The Carbatec 1200 cfm unit might be the go.

Or secondhand ...

Rgds,

I am two-thirds through building my new workshop and finalising the design of my built-in dust extraction system.
The Jet catalogue tells me how many CuFt/min I need to allow for each type of machine but it doesn't tell me anything about allowance for ducting distances. They refer to "static pressure loss" which I presume has something to do with duct length or similar.
Can anyone give me input on the impact of duct length?
I will have a total of about 20m of horizontal and 10 m of vertical ducting.

Also need diam of duct, type of duct IE flexible or rigid, number & type of bends IE 45° & 90° & amount of flow at the intake of the unit.

With all that, I can look it up in a book. (If I can find the book. )

Cliff
Since it is being designed, I can set it up as necessary.
But my prelim thoughts are:
1. 15m of 4" and 5 m or 5" rigid duct.
2. 10m of 4" flexible
3. 7*45 deg bends
4. Not sure what the flow at intake is...is that at the intake of the extractor or at the intake of the duct at the machine?

Note, that I will ever only have one machine operating at the one time and I will put in gates which I will close if the machine is not in use.

I hope this gives oyu the reqd info. And thanks for your help Cliff.


Gordon

Struth.:eek:

I found the book, this is going to be complicated.

PM me your e-mail address & I scan & e-mail the pages with the tables & explanations tomorrow.

I can't post it here 'cos we'd get in strife for breaching copy-write.

I need to send you about 16 A5 sized pages to read & that will pull it all together for you.

In the mean time, go & read these sections of Bill's web site.
http://billpentz.com/woodworking/cyclone/DC4Dummies.cfm
http://billpentz.com/woodworking/cyclone/Ducting.cfm

You could also read the whole lot but it will take several hours.
http://billpentz.com//woodworking/cyclone/index.cfm

If anybody else is interested, I have made up an 18 page .pdf on System Design about 330Kb with the tables & explanations.
PM me your e-mail address.

I have reviewed some of the references Cliff has sourced and summarise the key points as I have interpreted them for consideration in designing a dust extraction system:
1. The two objectives are to achieve a air velocities in the ducts above the required minimums (they are different for the branch and main ducts) and ensure the maximum static pressure loss across the system is less than the static pressure loss rating of the extraction machine. Air velocity is essentially determined by the capacity of the machine to move air, the type wood working machine being extracted, the length/diameter/type (flex or rigid) ducting and type/number of bends. So here are a lot of variables and you need to read the text to put it all together.
2. The practical take-away from my reading is that by far the most "costly" (in terms of needing to buy more power) is flexible duct compared to rigid (flex produces nearly 4 times the static pressure loss compared to rigid duct). It is much more "costly" than Y fittings compared to elbows(elbows produce less than twice the static pressure loss compared to a Y). The lesson here is minimise your flexible duct as much as possible. You should also of course use Ys rather than elbows.
I am still to finalise my conclusions about what equipment I will use, but the material Cliff provided was excellent.
Thanks Cliff.


Gordon

G'day,

Interesting comment above from Gordonwindeyer re: y's over elbows. I'll use a y on the next addition to my Dusty setup with the piece of machinery to be added.

Beauty Gordon.

You can see why it was easier to photocopy the pages & send them than it was to try to explain it.

The question wasn't as simple as just duct length.

I also spotted the advantage of Y fittings & rigid duct & I grabbed a handfull of Y fittings when they were on a junk clearance table a Bunnies.
I got 4 x 4" fittings for about $10.

The offer still stands for anyone else interested, I've sent out 5 copies so far.

Yeah, the tables have proved useful. Thanks Cliff!

I have a long main that terminates at my lathes, in a seperate section of the shop, where there's still plenty of suck but (as always) I'd like a bit more as I'm considering both above & below bed ports on the lathe. I've been toying with terminating the main after the main workshop machines and running a second main to the lathes, taking off from the first wye after the seperator. The idea being to maximise airflow by rediucing the no. of wyes en route. I've been hesitant to try it, 'cos ductwork isn't cheap and who wants to cut'n'install just to find you've made things worse?

But working the figures from Cliff's data, well... that project is back on the front burner.