# Dust extraction and hello



## Mgt280y (22 Oct 2018)

Good evening all just registered and already in need of help , been in the process of setting up my workshop and now on the task of dust extraction 

I’m a bit stuck on the calculations metric/imperial swapping and changing is confusing me 

Looking to have a central extraction now I have a a Rutland 50l metal type extraction unit at the moment specs are 4 inch inlet with the label saying 3m(3) per min and 53l per second. 

Now might be over complicating matters be I read that to run a ducted system around the room to each machine I need something like 3500 - 4000 FPM to suspend debris now I’m confused as I can work out how to work out how that would be achieved either my workings out are all wrong or the extractor is no where near big enough closest I have got so far was the inlet would need to be something like 2.5 inches I can draw up system and post with machine lists if that’s helps


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## sunnybob (23 Oct 2018)

Theres way too much theory in the world.
run the biggest pipe you can for as long as you can. Design the run to have the minimum amount of joints (especially T and 90 degree angle).
use as much rigid straight pipe as you can, keeping flexible hoses just to join the machine to the system.
Use a blast gate on each leg, keeping it as close to the main run as you can.
Sorted.


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## SammyQ (28 Oct 2018)

Beg to respectfully disagree Bob: 

Largest diameter pipe for SHORTEST distance....


Sam


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## sunnybob (28 Oct 2018)

Sammy... I think you have misread my reply.


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## SammyQ (29 Oct 2018)

Quite probably Bob. Just had two of the most slovenly painters here for for five days...my head's turned! Never employed painters before, never will again! Panicking to fix problems before relatives arrive.
Anyway, reread your post and I think we are both addressing the same point. You said to keep the major pipe 'big ' and only reduce if you're forced to when connecting to machines? Agreed. About tight turns? Agreed. 
My point was to try - on our amateur level - to keep the piping distance between our (relatively) wimpy dx's and the dust source as short as possible? That way energy loss through friction and 'boundary effect 'etc are minimised. Consequently, more dust gets dealt with? 
Pros that have multiple occupancy workshops ( or Murricans) tend to have dx's with two-figure horsepower motors that can overcome long pipe runs and their attendant energy losses. 

Sam


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## sunnybob (29 Oct 2018)

Yup, you have taken my "as big for as long" to mean making it longer than needed.
what was meant was to keep the pipe run in the large size for as long as possible (no reducers half way along).


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## SammyQ (29 Oct 2018)

Magic!


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## graduate_owner (31 Oct 2018)

Totally off topic but just wondering what you taught, SammyQ, and where. I taught in secondary school for 30 years.
K


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## SammyQ (31 Oct 2018)

Biology. 11 to 18. Campbell College Belfast, 1981 to 2017, where I was also a Housemaster. Also have a strong interest in etymology as Biology contains SO many terms that are more easily understood if you perceive their roots. Both contribute to me having a sustained penchant for precision of language that used to make my A levellers shake their heads and smile wryly - but it got them marks! 
That foible of mine was probably also responsible for me gently bearding sunnybob above; precise terminology equals clear, unequivocal communication. 

Sam


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## Phil Pascoe (31 Oct 2018)

https://www.amazon.co.uk/Little-Book-La ... 1408706164
Might interest you, it had a good review.


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## SammyQ (1 Nov 2018)

Clayx...phloem...indusium...gotta love 'em!

Sam


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