New Workshop - Dust Extraction Setup, What Size Duct?

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Jackus

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Hi folks,

Happy new year to you all!

This is my first post here, I am a joiner in Devon who makes windows and doors. I have recently moved into a new workshop (9x15 metres) and I am planning a new dust extraction system to go with it.

My plan is to run a central duct down the middle of the workshop for the 15m run and spur off it to connect into two spindle moulders, a bandsaw, and one planer/thicknesser either side of the central duct. Pretty uncomplicated so far.

My question is this! How on earth should I decide which duct size to go for? 160mm or 200mm both seem about right, but I really don't know how to decide, or what criteria you're supposed to base this off. For instance, is it the length of the run, or the number of machines that decides the duct diameter?

Basically, I am severely lacking in knowledge about dust extraction and would love to hear some words of wisdom on the matter!

Thanks,

Jack
 

baldkev

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Theres also a lot of info from bill pentz
Its not light reading, but loads of info.

Thats a great sized space!
Its partly going to be decided by the extractor itself. I got a tripple bag unit to cannibalise and it had/ has a 10" intake. Im aiming to reduce down to 6" at the machines, but no reason not to run the main branch in 10....
Theres a member called inspector who knows a lot about extraction, but it'll be something like this:
The bigger the better in terms of impeller. 15" would be perfect. The normal size for double bag units will be 12", which is less than ideal. A 4" duct flows sonething like 420cfm, so will never hit the 1000cfm that most machines would require. 6" minimum tube..... and a motor around 4hp.

Do you have 3 phase??
Im single phase, so either need a vfd or a 240v motor for my setup. Vfd's can allow the higher power to be achieved through 240v if the motor is dual power
And hi from south devon!
 

Doug71

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As it's commercial I would speak to someone like Dust Spares as in theory you should probably be having it tested etc. They would design a system that complied with all the relevant regs, you might as well start off with it done properly, might save having to do it again.

 

Jackus

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Theres also a lot of info from bill pentz
Its not light reading, but loads of info.

Thats a great sized space!
Its partly going to be decided by the extractor itself. I got a tripple bag unit to cannibalise and it had/ has a 10" intake. Im aiming to reduce down to 6" at the machines, but no reason not to run the main branch in 10....
Theres a member called inspector who knows a lot about extraction, but it'll be something like this:
The bigger the better in terms of impeller. 15" would be perfect. The normal size for double bag units will be 12", which is less than ideal. A 4" duct flows sonething like 420cfm, so will never hit the 1000cfm that most machines would require. 6" minimum tube..... and a motor around 4hp.

Do you have 3 phase??
Im single phase, so either need a vfd or a 240v motor for my setup. Vfd's can allow the higher power to be achieved through 240v if the motor is dual power
And hi from south devon!

Hi Kev,

Thanks for your thoughts on this! And to Bojam and Doug too. Very helpful.

The two machines I've been looking at so far are these:

Clean Air Dust Extractor - High Performance Line | Felder

iTECH STK6500 Fine Dust Extractor 65-8900cmh 7.5kw

To be honest, I am having a hard time understanding how these two machines stack up against each other. Obviously on paper the iTech machine is considerably more powerful than the Felder, but, from what I can understand (usually very little) the Felder is able to return 0.1mg of dust per cubic metre, while the iTech just says that its filters are rated to 5 microns. Is 5 microns good?

In the case of the Felder, 0.1mg/m3 is superb, and makes me think that I could simply leave the extractor on for 10-20 minutes after a particularly dusty operation (tenoning) to completely purify the air in the room. For reference, 0.1mg/m3 is dust category H, which is what you'd usually find on a specialist vacuum designed for really hazardous substances.

If anyone has any experience of either of these enclosed machines or anything like them then I'd love to hear how you're getting on with them.

Oh, and I am also in South Devon!

Best regards,

Jack
 

baldkev

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In terms of microns, 0.5 is the aim i believe..... even this pleated offering claims to achieve 1 micron

And now for the bit about claims.....
It seems a lot of manufacturers cheat with their claims. I have an axminster extractor which clains something like 950cfm, however it is fed by a 4" duct which can not flow those figures on its best day! Add in fine filters, bends and tube etc and the figure drops a lot.

I believe they test the machines with no restrictions in front or behind the impeller and take the measurements from the dead centre where flow should be strongest. All this means that often, you should 1/2 the claimed outputs to find a nearer figure....

Both look like good bits of kit. I would be tempted to email asking for confirmation of particle sizes that get filtered and if other filters are available.
Another option is to put them outside in a dust shed or build an enclosure within your workshop with fine filters over the air vents. I would imagine both units should be capable of safe fine filtering.

One area of importance will be the actual connection to your machines. In all the info and guidance pete ( @Inspector ) gave me, there was some suprising stuff about shapes of collectors and making sure your machinery has enough available airflow.

My planer thicknesser is an old multico, no hoods etc available, so i made one, but it never drew enough chips out and blocked easily. After reading the info, i drilled a series of holes in the front of my hood and the chips clear now.

Different machines work best with different types of airflow too, so you'll need to figure out what the best options are for you.
Spindles , thicknessers etc require lphv whereas a table saw or cnc work better with hplv. With a tablesaw, under bed extraction and crown guard extraction are desirable, with the extraction point on the crown guard being as close to the front as possible. I would imagine both of those units would be able to cover it, but worth finding out before spending..... ( i am no expert )
 

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Inspector

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Jack Kev is right. You want to filter down to .5 micron because the dust that is most harmful and is not normally visible is 10 micron and under. Both the collectors you linked use bags to filter the dust and they will filter finer dust than rated once they start plugging up with dust, called conditioning. Problem is that as the dust builds and filtering is improved the airflow is reduced. It is something of a tradeoff. Both will probably comply with your industrial air requirements although I didn't see where the black ones were made so am more leary of the specs, they are meant for commercial use so should meet legal requirements. Rule of thumb here was 1sqft of filter area for every 10 cubic feet of airflow. (My brain is too tired to convert to metric) so the 20 odd square meters is on the small size for the black one. Airflow specs, especially the ones aimed at consumers are inflated so expect half as much as promoted. If you are only going to use one machine at a time the Felder will probably work for you but if there are more that just you working you might need more so consulting with experts might be a good idea. What you should also do is to open up your machines to allow the air to flow through to pick up the fine dust. If the air isn't able to flow in to replace what is going out nothing goes out either. In many cases the machines need more openings for that flow, about 2 times the area of the port out to the dust collector. As Kev pointed out the duct size makes a difference to the flow. 4"/100mm max at 425CFM/722m3, 6"/150mm max at 1250CFM/2150m3. The Pentz site linked above calls for 1000CFM to capture the fine dust so 6"/150mm ducts would be minimum for most machines. Most any machine venting or siting outside is not a problem as the air isn't returned. When they are inside it is most important that they filter down to .5micron. Industrial cartridge filter specifications can be relied upon to be accurate where the import consumer cartridge filters are anyones guess.

Pete
 

Jackus

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Kev, Inspector.

Thank you both for the wise words. I should have joined this forum years ago!

Kev, regarding what you said about desired CFM and sizes for machine outlets, my spindle moulder is 6 inch, but my planer thicknesser, which is a modern machine, for who knows what reason is only 4", and has always been a little bit naff.

As regards the two extractors, I think I'll make some calls and try to nail down the two manufacturers on their specs so I can compare like for like.

The black machine is made in Turkey, as it happens.

Thanks,

Jack
 

Morag Jones

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This is helping me too - I won't be doing near as much as Jackus, but the problem is still the same.

I read the Bill Pentz pages last night, but I'm sort of stuck with the 4" outlets on my machines. I'm not willing to do what he did and cut bigger holes.
Question:
If the extractor has a 6" pipe, and the main spine pipe is 6" with a pair of 4" pipes off for each machine, say one for the built in spigot and one for the hood, would that be a good option? With blast gates to close off the ones not in use.

Or would I be better with a 4" system all over? I'm not at the machinery all day, but potter in the shed every day at something.
 

Jackus

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Off subject I know but when you get time how about a thread on how you are making doors, I am sure there would be a lot of interest from people to have this info from a someone who does it for a living.

That’s a good idea. When I get a chance I’d be more than happy to share a step by step explanation of my process and some photos.

Thanks,

Jack
 

baldkev

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If you can find a way to.open up that 4" port to 6" ( or remake the hood ) you'll find an improvement. I dont think my attempted attachment worked? It shows holes in the front of my planer cover and thru the holes you can see the chips getting sucked up.... so the extra air intake, which allows the extractor to flow properly, is aiding removal

If the extractor has a 6" pipe, and the main spine pipe is 6" with a pair of 4" pipes off for each machine, say one for the built in spigot and one for the hood, would that be a good option? With blast gates to close off the ones not in use.

I'd probably try it and see. Do you have enough kit or would you need to buy some pipe?
 

Sachakins

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You need to keep the biggest ductwork from the extractor that it can handle, and if you need to reduce to a machine then make that run as short as possible and branched off the main duct at full size then a smooth transition to smaller 4" duct after the branch off.
 

Morag Jones

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If you can find a way to.open up that 4" port to 6" ( or remake the hood ) you'll find an improvement. I dont think my attempted attachment worked? It shows holes in the front of my planer cover and thru the holes you can see the chips getting sucked up.... so the extra air intake, which allows the extractor to flow properly, is aiding removal



I'd probably try it and see. Do you have enough kit or would you need to buy some pipe?
I don't have any pipe yet other than a few short bits of Flexi that were attached to the machines when I bought them. So of course advice welcomed, better still cheap surplus!

I am happy to have a go at making hoods and stuff. But not so keen to take the angle grinder to my cherished 502E...
 

deema

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I’m guessing most of your machines will end up around the centre of the shop to give you 15’ either side feed / take off. I have very similar sized shop, I ran the duct across the centre (9m) and spurred off. This reduced the runs to a minimum.
If possible get the extractor outside. Have as much bag capacity as possible. 6 bags or more! Complete bind having to replace bags every 5 min where ever it’s located.
Outside you don’t need to worry too much about micron size, the finer the filter the more power it takes for the same CFM. Filters get glogged so anything decent requires air assisted shakers.
 

RobinBHM

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If you make windows and doors you might want to think about a 4 sided planer moulder. They are 8 times faster than a planer thicknesser.
 

RobinBHM

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For your set up, I would be looking ideally at a 3 bag unit with a 5kw motor and a main pipe whatever the extractor port is - 200mm, 225mm, 250mm

even this option won’t extract fully - exhaust hoods for planer thicknesser / spindle moulders don’t collect everything and the lower the extraction power the les chance you have of overcoming poor capture.


A 2 bag unit with say 3kw motor and 200mm port would be the minimum option.


Im not sure how the different filtration media options relate to real life. A traditional 3 bag unit has media with say 0.5 micron, but as the machine is used the filter gets a cake on it which acts as a trap.

fine dust filters, great though they are, lose capacity very quickly as they blind off. That’s why those big DCE fine dust extractors are used in industry for sanding machines - they have pleated filters for a huge area and mechanical shakers to clear.


Dont get too wrapped up in comparing manufacturers ratings as a comparison basis.


Personally if it me, I’d buy a 2nd hand 3 bag unit, get a set of brand new filters - you should get all that under £1k delivered.
 
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