Dust Extraction Air Flow

[Tenson]

Hi,

I'm looking to get some dust extraction. I can't help thinking some of the air flow figures on Axminster are bollox but would like some feedback on that!

Example my current Numatic NV750 is apparently moving 150 m3/hour.

An older WV 2000 extractor for sale not far from me is apparently 125 ltr/s or 450m3/hour.

Then suddenly the new extractosr on Axminster like the AWEDE2 is rated at 850m3/hour which is no small increase!

Then even more crazy the FM300BC (not an expensive machine) is supposedly 2000m3/hour!!

Is this fudging numbers like measuring with / without the inlet in place or comfusing cfm and m3/m something?? Or is it just down to some extravtors having finer filtration?? I'm a bit confused here.

Thanks!

 

[sunnybob]

A fan motor is usually rated as free flowing. No filters adaptors or pipework.
Every foot of pipe, every fitting, even corrugated flexible hose will eat into those figures very quickly.
might be better measuring HP as a sign of how good it can suck.

I have a sip 50 litre can with 4" inlet rated at 1.5 HP. It works pretty well on my hobby machines.

 

[WellsWood]

The AWEDE2 and FM300BC machines are HVLP chip extractors, unlike the others which are vacuum extractors (HPLV - aimed at removing fine dust due to higher levels of filtration). As such it is pointless to compare specs between the two. What machines are you intending to hook them up to, and what materials will you be using?

 

[PAC1]

Sadly it is very confusing, a further factor is you need to know the inlet size as many will measure the flow based on say 175mm or 200mm inlet and then provide you with a 100mm inlet. This gets very confusing because you might think 100mm is half 200mm so just halve the flow. Nope mathematically the area is a quarter the size and then air does not simply accept the restriction and compensate for it.
Unfortunately the only way to decide is to look very carefully at what is being measured how it is measured and under what circumstances. you then need to take on board that real life, small ducts (100mm or less), bends, junctions, cyclones, separators and flexible ducts all conspire to significantly reduce the flow. Add to this most machines have poorly designed dust ports and you soon realise that you need a much bigger extractor than first thought.
Good luck!

 

[Tenson]

Thank you for your answers!

Noted about hvlp and hplv. My Numeric NV750 has a high filtration level but I feel like it just doesn't move enough air because one you get a few inches from the inlet it doesn't pick up much.

I'm hoping to use this for a number of things. I have a CNC router with a dust shoe that has a brush around the edge... but if the brush doesn't make perfect contact the pickup becomes rubbish with the current NV750. I mostly cut plywood and solid wood and plastics, not often MDF. I also want to experiment with making a down-draft table for sanding with less mess. My bench nd also palm sander have dust collection but I'm still left with a film of dust over the workshop an hour later. Thinking of using it for my vacuum table for workpiece hold down too, but it's probably not going to work well if also doing dust extraction at the same time.

The wv2000 seems to have the same 0.5micron filtration as my Numeric which is impressive. Anyone got one and can comment if it doesn't move as mu h air as the newer chip extractor?

 

[LancsRick]

You want LVHP. I'd suggest a good workshop vacuum with a DIY cyclone and drum in the middle rather than buying an all-in-one solution personally.

 

[WellsWood]

Sadly, what most people seem to need is the best of both worlds: high air flow AND high vacuum, which is the remit of pretty expensive industrial kit that takes up large amounts of space.

I've tried all sorts of solutions over the last 25 years the best of which is undoubtedly a 2 machine setup :-
a small ducted system with blast gates running from a vacuum extractor (WV100) - for router table, power tools etc., and a basic bagged HVLP chip extractor (like the AWEDE2) for the P/T, B/S and tablesaw.
In an effort to claw back some floor space I moved over a few years ago to an NV750 (the wall mounted version) for everything. I have it hooked up to 100mm galvanised ducting with blast gates and a remote switching system, and a dustbin interceptor located next to the P/T to accomodate the large volume chips. The original 2.5" ducting is connected to the 100mm stuff and remains in place to deal with finer dust from sanders, router etc. It just about copes with everything and is as near as my budget and space allows to a one-stop solution. The price is it's a bit less good at all the individual tasks than running 2 machines, particularly regarding T/S and B/S, the latter being especially problematic regardless of which kind of extractor is used.

I have found that the NV750 requires regular and frequent cleaning of the filters to maintain good performance. It could be quieter too!

 

[Tenson]

You want LVHP. I'd suggest a good workshop vacuum with a DIY cyclone and drum in the middle rather than buying an all-in-one solution personally.

Can you explain why, please?

P.S. You read I've already got an NV750, right?

 

[woodbloke65]

Sadly, what most people seem to need is the best of both worlds: high air flow AND high vacuum, which is the remit of pretty expensive industrial kit that takes up large amounts of space.

I've tried all sorts of solutions over the last 25 years the best of which is undoubtedly a 2 machine setup :-
a small ducted system with blast gates running from a vacuum extractor (WV100) - for router table, power tools etc., and a basic bagged HVLP chip extractor (like the AWEDE2) for the P/T, B/S and tablesaw.
In an effort to claw back some floor space I moved over a few years ago to an NV750 (the wall mounted version) for everything. I have it hooked up to 100mm galvanised ducting with blast gates and a remote switching system, and a dustbin interceptor located next to the P/T to accomodate the large volume chips. The original 2.5" ducting is connected to the 100mm stuff and remains in place to deal with finer dust from sanders, router etc. It just about copes with everything and is as near as my budget and space allows to a one-stop solution. The price is it's a bit less good at all the individual tasks than running 2 machines, particularly regarding T/S and B/S, the latter being especially problematic regardless of which kind of extractor is used.

I have found that the NV750 requires regular and frequent cleaning of the filters to maintain good performance. It could be quieter too!

I've just upgraded mine with a Oneida Super Dust Deputy running from my original Camvac twin motor extractor, everything collected in a 220l water butt with PRV (mandatory!!) The Camvac exhaust ports are directed under the suspended floor so nothing gets back into the 'shop. The system now effectively deals with chippings from the Jet 260 p/t, sawdust from the big Ax bandsaw and fine sanding dust from the disc sander, lathe and Jet 16-32 drum sander. I also have a 'gulper' connected to the system for cleaning up the floor. The only thing I have to do is to shake out the filter from the Camvac each Sunday morning - Rob

 

[LancsRick]

Based on what you've described there, the airflow you need is high velocity in a small area to pick up from those tools. That gives lvhp.

For picking up cnc debris that escapes the shoe, you'd be better encasing the machine and having a secondary system pulling hvlp through the cabinet