Thread: Alternative Dust Extraction Solution

Originally Posted by mick59wests

First - what I believe I need to find out:
1. Confirm that the 3 x 100mm inlets can be pulled out to expose a 200mm inlet.

Correct

2. Determine the real cfm. I do not expect to get anywhere near the 2300 cfm but if I have a single 8" port and only take it down to 6" and only leave one open at a time, surely I will get at least 1000cfm. I think I have read about impeller size and rpm for the motor so will do some more investigation. What I am really hoping is that Timless Timber (or the guru BobL who helped TT) have done this but I am certainly happy to do my own research. They guy at hairy forbes did not know the impeller size and was only guessing it was 1440 rpm so I plan to go their tomorrow and get some more information.

It should be a 2850 rpm motor. If it is 1440 rpm I wouldn't touch it.
If they claim 2300 cfm you can expect to get about half that. I expect that machine should be able to get 1250 cfm with clean bags and shortish runs of 6" ducting.

However, if you are going to be buying a new machine I would aim for a model that has the impeller directly connected to the bags like this
Woodfast Machinery Co. (Aust.) Pty. Ltd. -
These machines will have better flow under load compared to those that use ducting between the impeller and the bag housing.
Unfortunately I hear that the 3HP Woodfast DC is pretty noisy.

My guess is you are probably not up for it but getting the 3 phase motors DC has a major advantage in that a VFD can be used which can speed but the impeller by 20% and generate a 20% flow increase. Of course this makes minimal difference when the bags are clean and if the ports on machines are well opened up and free breathing. However, once the bags become slightly clogged and where work pieces or processes block air flow on machines the extra puff generated by superior machines will maintain the required air flow for much longer. 3Phase wiring is not required if a VSD is used but paying a sparky to do install the VFD won't be cheap either.

6. It runs on 10amps so I may not need any additional electrical upgrades (I still need to confirm this)

It will almost certainly be a 15A plug the start up currents will be upwards of 50A

7. It will be cheaper to run

I did the sums a while back and based on 10A @ 240 - single phase, versus 10A @ 240 - 3 phase there is a saving of around 40c an hour , but when I estimated how much I was using the DC it averaged less than an hour a day so the savings weren't that dramatic. I have a very good room air scrubber that only draws 300 mA so I don't need to scrub using my DC.

So, my real question is - what have I missed? I know the CearVue is very much a superior machine but will this be good enough?

Good enough will depend on usage rates, type of usage, lengths of ducting runs and how well you can modify ports on machines. There is probably more handiwork needed to modifying machine ports than installing a Clearvue.
The machine port modifications are absloutely vital in achieving the 1000+ cfm flow rates - unfortunately there are no plug and play solutions.

Originally Posted by BobL

Correct


It should be a 2850 rpm motor. If it is 1440 rpm I wouldn't touch it.
If they claim 2300 cfm you can expect to get about half that. I expect that machine should be able to get 1250 cfm with clean bags and shortish runs of 6" ducting.

However, if you are going to be buying a new machine I would aim for a model that has the impeller directly connected to the bags like this
Woodfast Machinery Co. (Aust.) Pty. Ltd. -
These machines will have better flow under load compared to those that use ducting between the impeller and the bag housing.
Unfortunately I hear that the 3HP Woodfast DC is pretty noisy.

Bob,

very much appreciated. I can see how the design for the woodfast would have a better flow rate under load and I certainly like the fact that the 3hp has a 200mm outlet. I'll make some enquiries about size and noise but if this fits into the wood shed it looks a better alternative than the H&F.

I can see myself getting it setup and going for my lathe first (and having this the closest machine) followed by the bandsaw. I have seen your 'gulp' for the lathe and John Samuel's thread which includes 3 x 4" ports for the bandsaw. There was also an interesting hood/cover posted by gidgee 1 for the lathe.

I'm sure I will be asking for further assistance before then and I may even get some time to do some turning!!! Certainly before doing any ducting I will post 'my plan'.

thanks again

Mick

PS: It is so great to have someone knowledgeable giving their time and expertise to this very important aspect of woodworking. I am sure there are many others out there who have better health because of you.

Originally Posted by mick59wests

6. It runs on 10amps so I may not need any additional electrical upgrades (I still need to confirm this)


ORDER CODE
W329

Originally Posted by BobL

It will almost certainly be a 15A plug the start up currents will be upwards of 50A

Whoops!

It would be interesting to know how they do that.

I'd like to see if the machine has the original plug on. 3HP motors usually have a 15A plug.

Originally Posted by NCArcher

I'd like to see if the machine has the original plug on. 3HP motors usually have a 15A plug.

I wonder if it might have some basic soft start circuitry on it?

I'll try to get in next week to hairy forbes and have a look. I got too busy doing that four letter word (work) this week.

Now that I am looking at this alternative, I am expecting the main drawback will be keeping the required CFM over time as the filters get dirty. Are there any tricks / rule of thumb for this? I can't say I would be keen to give them a good clean every woodworking day but if I......
- daily after use (and with my powered respirator on) gave them a bang to dislodge settled dust
- maybe after ten uses or when I need to empty the bags take them out and vacuum the insides or....
- maybe even put pinprick holes in the filters (I am not sure if this is lateral thinking or just shows how little I still understand ) to increase air-flow as it will be outside my shed


Mick

Originally Posted by mick59wests

I'll try to get in next week to hairy forbes and have a look. I got too busy doing that four letter word (work) this week.

Now that I am looking at this alternative, I am expecting the main drawback will be keeping the required CFM over time as the filters get dirty. Are there any tricks / rule of thumb for this? I can't say I would be keen to give them a good clean every woodworking day but if I......
- daily after use (and with my powered respirator on) gave them a bang to dislodge settled dust
- maybe after ten uses or when I need to empty the bags take them out and vacuum the insides or....

Daily cleaning will become a nightmare and unless you do the exact same WW activity all the time any time based cleaning schedule is not really the way to approach this.

The best way is to measure actual flow rates and clean the filters when the flow rates drop by a fraction that works for you. Even with the flow rate gear I have this is a PITA so an easier way is to use a manometer to measure the back pressure generated by the filters. This will take some investigating because when the filters are new they will have a much lower back pressure than they will ever have - and also let a lot of dust through. After some testing of new filters I estimated it takes about 30 hours of running in just atmospheric air to get them to the point where they are trapping wood dust like they should be. This initial conditioning could be done much quicker using wood dust but remember while you do this lots of fine dust will be passing through the filters into your shed - this is another reason why venting the DC outside is the way to go.

With use the filters will become clogged and matted and once clogged no amount of subsequent cleaning will quite get then back to where they were when they were new and not that you'd want to go through that initial conditioning (that should be done with new filters) every time the filters are cleaned. After measuring the pressure with a manometer over several cleaning cycles you will have a good idea of what constitutes "clean" filters and when it is time to clean them.

- maybe even put pinprick holes in the filters (I am not sure if this is lateral thinking or just shows how little I still understand ) to increase air-flow as it will be outside my shed
Mick

Not a good idea and not very effective.
The pins are more likely to just push the filter fibres aside rather than make new holes and the pushed aside fibres will just close back up again.
If you have to cut the fibres to make holes it let visible dust escape which will make a real mess.

BobL,

thanks very much once again. This is increasing my understanding but making me re-think back to a cyclone solution where I then don't have a filter issue if I vent outside the shed. I definitely need to get my extra 'little shed' height next weekend and work out what will fit. Also, a bit more research and digging (and probably some navel contemplation ) before deciding. While i am still in Sydney I will do my best to see a ClearVue installation to determine what I am up for if I go down this path.

thanks again

Mick

Originally Posted by mick59wests

BobL,

thanks very much once again. This is increasing my understanding but making me re-think back to a cyclone solution where I then don't have a filter issue if I vent outside the shed. I definitely need to get my extra 'little shed' height next weekend and work out what will fit. Also, a bit more research and digging (and probably some navel contemplation ) before deciding. While i am still in Sydney I will do my best to see a ClearVue installation to determine what I am up for if I go down this path.

thanks again

Mick

If and when I go for a cyclone, even though it will need to be located outside the shed I will also need to deal with the height problem . One possibility is to dig out a recess in the ground and line the recess with plastic. Preventing it filling up with water will require a little bit of thinking but shouldn't be rocket science.

Originally Posted by BobL

Good enough will depend on usage rates, type of usage, lengths of ducting runs and how well you can modify ports on machines. There is probably more handiwork needed to modifying machine ports than installing a Clearvue.
The machine port modifications are absloutely vital in achieving the 1000+ cfm flow rates - unfortunately there are no plug and play solutions.

I can confirm that Bob is right. Installing the ClearVue was not really a big deal. The ductwork was easy. I spent more time modifying all the machine ports/hoods/shrouds than I did on anything else. We really must modify these hoods. Putting in a decent DC solution is a WOFTAM if we don't. I reckon I am getting a fair bit better than 1,000 CFM, but the original ports on my machines would likely have throttled this to 400 CFM or less.

Originally Posted by BobL

Correct


However, if you are going to be buying a new machine I would aim for a model that has the impeller directly connected to the bags like this
Woodfast Machinery Co. (Aust.) Pty. Ltd. -
These machines will have better flow under load compared to those that use ducting between the impeller and the bag housing.
Unfortunately I hear that the 3HP Woodfast DC is pretty noisy.


Good enough will depend on usage rates, type of usage, lengths of ducting runs and how well you can modify ports on machines. There is probably more handiwork needed to modifying machine ports than installing a Clearvue.
The machine port modifications are absloutely vital in achieving the 1000+ cfm flow rates - unfortunately there are no plug and play solutions.

I am still researching / understanding / crystal ball reading / navel contemplating but I am now thinking.......

the 3hp woodfast above is 'rated' at 2800cfm and has a 200mm inlet so if I....
- put a cyclone in between (a good one with 200mm inlet and outlet - I'll talk to Stephen about the attachments for the ClearVue)
- remove the filters (and bag) from the Woodfast and vent outside
should I expect to get 'the magic numbers'?

I think by removing the filters but adding a cyclone, as long as I am only running a single machine and have less than a 10m run with no nasty slowdowns such as straight 90 degree turns I should be pretty close.

I am thinking my lathe will be closest so could fully use 200mm ducting ( or will this slow down the fpm too much ).

For the bandsaw I would have multiple ducts (as per John Samuel) and the same for the tablesaw.

Would it be better if I used 150mm or 200mm ducting (disregarding cost for the moment)? I have even seem some 165mm PVC. I have seen a fair bit of discussion on this but have not completely understood the mathematics. I am thinking this should be able to be included in a spreadsheet and I could plug in the numbers and see the optimum results for what ducting to use..... If anyone has developed this......

In doing the above, I don't need a 99.x% capture in the cyclone as where I will be venting will be at least 50 metres from the nearest neighbours and 20 metres (in the opposite direction and over the shed) from the washing. This all has the distinct advantage that I can house the motor and venting in my 'wood shed' and vent completely outside. My openings (garage doors and / or window) will be 10 metres or so from the venting.

I still need to check the amp requirements. The woodfast salesman did say it was 90db at source so I am keen to have it outside my shed where I can do some insulation if needed.

All thoughts are always (well nearly ) greatly appreciated.

cheers

Mick

Originally Posted by mick59wests

I am still researching / understanding / crystal ball reading / navel contemplating but I am now thinking.......
the 3hp woodfast above is 'rated' at 2800cfm and has a 200mm inlet so if I....
- put a cyclone in between (a good one with 200mm inlet and outlet - I'll talk to Stephen about the attachments for the ClearVue)
- remove the filters (and bag) from the Woodfast and vent outside
should I expect to get 'the magic numbers'?

I would basically ignore what the manufacturer says about air flow.
The 3HP wood fast should be capable of 1250 cfm using 6" with clean bags and shortish ducting.
With 8" ducting there could be significant probs, i.e. read on.

I would be very wary about running such a 3HP machine with an 8" intake and ducting as there is a chance that the air flow may be too great and thus the current drawn by the motor will be too high which will damage the motor. What you would need to do is measure the current drawn by the DC with the 4 x 100 mm ports running i.e. as supplied and then run it with them fully removed. If there is a significant greater current being drawn by the 8" inlet then running the motor long term like this could be a problem. I cannot tell you what a safe current will be because that will be specific to each motor and whether it has a thermal safety cut out and where that is set. The current drawn with the 8" could also be borderline and while it might be OK for a some time after installation, but maybe even a few years later on an extra hot day the current will just be too much for the motor.

I think by removing the filters but adding a cyclone, as long as I am only running a single machine and have less than a 10m run with no nasty slowdowns such as straight 90 degree turns I should be pretty close.

What sort of cyclone are you thinking of adding? Unless it is a recent design such as the Clearvue the cyclone could seriously detract from the flow. A basic cyclone or chip catcher lose up to 25%, This means the 1250 cfm I indicate above could be as around 930 CFM using a cyclone. The Clearvue is developed specifically for a specific size motor and impeller and there is no guarantee that the same performance will be obtained with a 3HP motor and smaller impeller. Given this I honestly don't think it worth buying a woodfast and then a Clearvue cyclone component and then mucking about trying to mate the two together.

Several members have built BP style cyclones using 3HP motors and smaller impellers. I don't believe any have been accurately tested for flow or particle filtration but it would be interesting to hear from them.

I would be one of those who built my own, I use a 3kw (4hp) with a 12" dia. fan, I have done some basic static manometer testing to indicate flow but this may not be sufficiently accurate due to edge effects at the end of the pipe as Bob pointed out in another thread, it would be interesting to determine the actual flow of my machine using other methods but I don't have such gear



Pete