Dust Collection for 15 Lathes! On a 3Hp DC - Is this even possible?

[Darcy Williams]

Hi guys,

I'm based down in New Zealand and have been tasked with trying to design our workshop dust collection layout - For a woodturners guild. I've done a bit of this for at home, but I only had a few bits of equipment connected up to my 2Hp DC. Easy, and very forgiving...

This is all being installed in to our new club-rooms which are currently on-site and being joined to our existing club rooms - more than doubling the footprint. The existing rooms will become used for general wood-working, while the lathes are moved in to the building with the reinforced floor

Duct Plan - Lengths are accurate, but duct sizes/diameters TBD
duct lengths v1.jpg

duct_overhead1.jpg

duct_overhead2.jpg

But... I've been given this task to do, with one main restriction. In NZ, to get more than 2.2kW (3Hp) you need to bring all three phases in to your building, and pay an increased per month meter rate. We're a non-profit (registered charitable entity) club, so that's not appealing. On the flip side, the dust collection setup up-front cost is paid by charitable grants... so in theory we can get a pretty decent DC up-front. In short, I'm limited to a single phase. And a single phase motor is limited to 2.2kW on a dedicated 15A 230V socket. Fine, so be it...

Up until I took this over, the plan had been to rely upon six air cleaners, and four mobile 1Hp DC's that get dragged around. That meant that we either had to give up all hope of storage (the white shelving in the pictures), or have less than 15 lathes - which is already a bit short. Because I didn't like that idea, fairly enough, I've now got to put together the alternative. The downsides of the prior proposal were: A lot of noise, obstructed walk-ways, no room for storage - we're already quite pressed for storage, and non what-so-ever had been allowed for in the new building!

Anyway... So, a typical usage scenario is that any 3-5 lathes may be collecting dust at any one time (usually only 1-3). In our current club-rooms we don't have anything... at all... we open the windows and doors, and power-sanding (drill + sanding mandrel) is frowned upon.

My limitations are as follows:
- The DC needs to stay in that location
- The duct going through the walls can move vertically, but not sideways (due to bracing wall restrictions)
- The duct should ideally stay at head height (2.7m stud) - except for the bandsaw outlet
- The dust collector is limited to 3Hp!!!
- In NZ, anything bigger than a 5" blast gate isn't financially viable. Blast gates of 4" diameter are common, and cheap enough

Other considerations:
- The DC will be used for fine dust collection only. There is no intention to gather shavings of any sort (except the inadvertent kind...)
- The DC will have wireless remotes fitted for on/off
- Every lathe will have 5-6" duct running to it, dropping down to a vertical, with a 4" reducer, a blast-gate, then at most 1.2m (4ft) of 100mm flexi-duct

Other points of interest:
- The DC will be in an enclosed semi-sealed room, except for at least 2x 8" vents out through the floor, to underneath the building. This is done in an attempt to deaden sound and avoid the use of ear-protection when operating
- The band-saw is used infrequently and has a recommended 800CFM collection from a single 4" port (still not sure how that's supposed to work!)
- There will be a short length of 200mm flex-duct to isolate vibration from the DC to the ducting (just a few hundred mm)

If we can collect 80-90% of the dust, we'll be pretty happy. One of the advantages of this system is that we'll be constantly drawing fresh air in to the clubrooms. Our normal open hours are during the day so heating typically isn't a problem (i.e. since we'd be sucking out warm air and discarding it - were we heating it). The option exists here that if we find this system to mostly do the job, but isn't quite enough... in a couple of years we can upgrade it but keep the ducting in place.

I've tried a variety of different ducting layouts, but this seemed to be the best method of reducing bends, and having no more than two points of collection on any branch. It uses a bit more duct, but I think it simplifies the calculations

I'm just a bit stumped on how to calculate from here! I have a full spread of duct to chose from, I'll chose smooth wall duct wherever possible, and wide radius bends wherever I can. The duct sizes are from 100 - 200mm, 4 - 8", in 25mm steps. So, I can go nuts when it comes to choosing specific diameters... but I'm a bit of a loss on how to calculate for this setup! I'm pretty certain I now have enough information to begin calculations, but where to begin? I've allowed for 200mm ducting coming out of the DC and in to the main trunk... but what happens if only one blast gate is open? So many considerations I don't know where to start.

After a bit of research, I'm pretty much limited to one of two DC's. The retailer was very helpful and spent a couple days chasing up specifications for me. I really need to recommend Carbatec in NZ for their service!
3Hp Two Stage Cyclone CDC-2200C (UB-3100ECK)
Volume - 2200 CFM
Impeller - 15.8"
Static Pressure - Attached
cdc-2200c.JPG





3Hp Twin Bag DC-2200C-3P (CT-003VB-1PH)
Volume - 2200 CFM
Impeller - 14.5"
Static Pressure - Attached
The attached spec is from the 3 phase version of the same product. Supplier has stated the only difference is the 3 phase power requirement, and that performance is identical.
DC-2200C-3P.JPG


Each Lathe will have something like this dust-chute, for collecting fine dust (10" x 4" with 4" port)




Any help in this would be greatly appreciated... It looks to me like the Cyclone DC is the more powerful unit. But I still need to work out duct diameters.

Cheers
Darcy

[Chris Parks]

Darcy, I am in Oz so can understand the problems and have seen some of them. First question I have, what is the total current draw you can tolerate? There are ways around this but it depends on the total power supply that can be dedicated to all the DE in the shed. PM me your phone number and email and we can have a chat on the phone.

[Wayne Lomman]

Darcy, I am in Tasmania. We only have single phase and can run a 5kw motor to drive the dairy vacuum pump. It was hard wired and didn't cost much to run. A 2kW dc feels a bit light on to me. Your layout looks good. Have you tried an air-conditioning mob for airflow advice? Cheers

[Robert Engel]

I recommend hiring a DC designer. Perhaps Carba Tec can do this for you. I know most major companies like Oneida, Clear Vue will design a system for a fee even if you don't buy from them.

IMO hiring a consultant is well worth the up front investment before you equipment.

I think you're looking at multiple blowers.

[Chris Parks]

There are no professional designers in this field for hobbyists in Oz and I would think the same would go for NZ. I was the Clearvue distributor in Oz for some years and could help Darcy if he wants to take up my offer to contact me.

[Jamie Buxton]

Is there anything in the electrical regulations that prevent you from using multiple 3-hp cyclones?

[Jim Becker]

One thing to consider...dust collection at the lathe is pretty much limited to to use when sanding and for a floor sweep. You really cannot "collect" chips while cutting on the lathe since they tend to go in every direction but toward where you can put any kind of pickup. Therefore, DC is more for "convenience" relative to the floor sweeps and actual dust collection only when sanding.

[Frank Pratt]

One 3 HP for all would not collect much of anything, fines or chips. I have a 5HP Onieda & if I've got gates at the table saw, jointer & planer all open, performance starts to suffer.

What you are going to need, really, is a small (2 or 3HP) collector for each lathe. That may not be as bad as it sounds. Ducting everything back to 1 collector is very expensive, so you would save that cost. And you can get some pretty cheap small collectors.

Interestingly, we just did some electrical work at a new woodworking shop (about 27,000 sq ft) and they have no central dust collection. Each machine has it's own blower, cyclone & filter.

[Darcy Williams]

Heya Jim,

Thanks, yes, you're correct. I tried to clarify that we only intend to use the DC for fine dust collection. No chips or shavings... Those just get swept up by hand at the end of the session.

[Darcy Williams]

Darcy, I am in Oz so can understand the problems and have seen some of them. First question I have, what is the total current draw you can tolerate? There are ways around this but it depends on the total power supply that can be dedicated to all the DE in the shed. PM me your phone number and email and we can have a chat on the phone.

Giday Chris, thanks for the offer. I'll PM my email address to you. Each phase is limited to 63A, with a 3Hp unit requiring a dedicated 15A socket.

Ideally, I'd like to work out whether either of those units will meet our requirements for the next couple of years - at which point we could investigate installing 3 phase.

The biggest thing that has my attention is trying to ensure the ducting is correct. Upgrading the DC in the future is much easier than replacing all the duct-work.

One 3 HP for all would not collect much of anything, fines or chips. I have a 5HP Onieda & if I've got gates at the table saw, jointer & planer all open, performance starts to suffer.

What you are going to need, really, is a small (2 or 3HP) collector for each lathe. That may not be as bad as it sounds. Ducting everything back to 1 collector is very expensive, so you would save that cost. And you can get some pretty cheap small collectors.

Interestingly, we just did some electrical work at a new woodworking shop (about 27,000 sq ft) and they have no central dust collection. Each machine has it's own blower, cyclone & filter.

Hi Frank, the reason for not doing this is in my original post. Each individual DC then consumes floor space. If floor space is a premium, then you have to start sacrificing either the number of lathes you have, or the amount of storage available. The up-front cost of using ducting is something we can manage through the use of charitable grants through community trusts.

Is there anything in the electrical regulations that prevent you from using multiple 3-hp cyclones?

Only sort of... There are limits as to how many 15A sockets you can have. And space becomes a bit of an issue. Also, because of how the ducting goes through the walls, it would be very awkward to run multiple 200mm/8" primary trunk ducting. So ideally we just have a single DC. Plus, those beasts are $4300 each!!!!!!!!

Darcy, I am in Tasmania. We only have single phase and can run a 5kw motor to drive the dairy vacuum pump. It was hard wired and didn't cost much to run. A 2kW dc feels a bit light on to me. Your layout looks good. Have you tried an air-conditioning mob for airflow advice? Cheers

That's an interesting one... I guess that could be possible, but we'd need to hard-wire the DC in to the wall. We'd also have to build a custom DC system from components. For the most part, anything more than 2.2kW in NZ requires 3 phase. You would struggle to find a 4-5 Hp single phase motor in NZ. I've tried one DC crowd but I their initial quote was a ridiculous $24K

Thanks guys.

[Chris True]

Don't see why you couldn't branch the main to side by side cyclones operating together. Expecting a 2hp collector to do anything with 5 gates open is insane

[Frank Pratt]

[QUOTE=Darcy Williams;Hi Frank, the reason for not doing this is in my original post. Each individual DC then consumes floor space. If floor space is a premium, then you have to start sacrificing either the number of lathes you have, or the amount of storage available. The up-front cost of using ducting is something we can manage through the use of charitable grants through community trusts.[/QUOTE]

Hmm. Sorry, missed the part about floor space. Any way you could configure small collectors suspended from the ceiling? I just don't think you can get what you want out of 1 3HP collector for all lathes.

[Darcy Williams]

Don't see why you couldn't branch the main to side by side cyclones operating together. Expecting a 2hp collector to do anything with 5 gates open is insane

Hi Chris, Well... 3Hp, but close enough :-) Yes, it is a challenge... I don't think I'd fit two DC's in the available space/room. For now, we'll be happy with collecting from three units - but I still need help to sort out duct diameters.

[Darcy Williams]

Hmm. Sorry, missed the part about floor space. Any way you could configure small collectors suspended from the ceiling? I just don't think you can get what you want out of 1 3HP collector for all lathes.

Yeah, it makes it challenging. There's a 2.7m stud, giving me 0.5m to work in. That's enough to run ducting and that's about it. If I get the duct sizing right, I can upgrade to a three phase DC in the future... but that's a couple years down the track.

[Larry Frank]

First, you are trying to do a good thing with difficult circumstances.

The rated cfm of 2200 cfm for the cyclone is very optimistic based upon what I have read and studied. The cyclone looks a lot like the Laguna and several other brands. These are nice machines but I would worry that the short cone will be an issue when collecting sanding dust from the lathes.

With that cyclone, trying to collect from 3 lathes at once and even if you got the 2200 cfm, your velocity in the 8" ducts will be too low to keep everything moving.

I wish there was some easy answer and I hope others can help you.