Dez Built 1st January 2017, 08:44 PM Hi all,
I am planning on modifying my dust extractor as per Bobs's thread to open it up and improve effecency. As part of this, I wanted to vent excess outside after chips are collected as I currently have no way of reloccating the whole unit outside the workshop. In other words, I want to get rid of the excess fine dust outside as the pleated filters just don't completely filter the fine dust and it ends up being recirculated inside the workshop. Because I live in suburbia, I'm worried about spraying dust around the neighbourhood so my thoughts were, the only way to achieve this would be to attach my modified dust extractor on top of a cyclone and the exhaust side can be vented outside negating the need for the bags and pleated filter set up. See the attached picture of cyclone I had in mind.
Will this his set up work effectively without too much loss of suction?http://www.woodworkforums.com/webkit-fake-url://19c09dab-afce-411d-aada-48b87e8a37fa/imagejpeg
TinyTool 1st January 2017, 09:19 PM I've done something similar to what you are thinking of but I converted the filter / bag housing unit into a form of Thien (?) Top-hat separator, attached this to a plastic chemical drum (44 gal I think) and installed the Motor and Impellor on top. The Unit has a footprint equal to the footprint of the drum which is situated in my shed and I vent outside. I have found no loss of suction, actually it is better because I have no filter's to worry about.
Unfortunately, the 6inch vent outside the shed occasionally emits a fog of fine dust and shoots it out about 20 feet. I live on acreage.
Geoff
Lappa 1st January 2017, 09:45 PM No Photo?
BobL 1st January 2017, 10:46 PM Hi all,
I am planning on modifying my dust extractor as per Bobs's thread to open it up and improve effecency. As part of this, I wanted to vent excess outside after chips are collected as I currently have no way of reloccating the whole unit outside the workshop. In other words, I want to get rid of the excess fine dust outside as the pleated filters just don't completely filter the fine dust and it ends up being recirculated inside the workshop. Because I live in suburbia, I'm worried about spraying dust around the neighbourhood so my thoughts were, the only way to achieve this would be to attach my modified dust extractor on top of a cyclone and the exhaust side can be vented outside negating the need for the bags and pleated filter set up. See the attached picture of cyclone I had in mind.
Unless the pleated filters have holes in them (possible) the dust problem is not usually with the filters but the sealing around the bags and filters.
Pleated filters get holes in them when too much dust is being left in the bottom bag and big chips are circulating up inside the filters :no:.
To avoid this problem the plastic collection bag should be emptied when the bag is no more than 2/3rd full and preferably when it is only has full
The plastic collection bags are much more susceptible to holes as more wood chips etc spin around inside that bag.
Using a cyclone in such a situation is completely counter productive. You plan to spend time and effort to generate an increase in flow of your DC and then you are going to add a device (a cyclone) that will slow dow the flow by almost as much as you plan to improve it.
Cyclones are for vacuum cleaners or large DC that both can afford to lose some flow rate. Vacuum cleaners don't lose much flow because they operate at about 3X the pressure of a basic DC. Larger DCs already have so much excess flow if they lose 10% or even 20% of that flow it does not matter.
With a small DC, if you want maximum flow as many impediments to air flow need to be removed from the air path way.
This means
- no chip collectors or cyclones,
- as large a ducting as is practicable,
- machines ports opened up and machines allowed to breathe,
- and religiously keeping the filters clean.
Allowing any of these to fall down will result in loss of flow
Every impediment to air flow means less air and hence less fine dust is being collected at the source of the problem leaving it to spread around and contaminate a shed.
Cleaning this escaped dust up after it has escaped is like herding cats.
The KEY is grabbing as much of that dust right where it is made. SO focus on maximum flow and the rest will fall into place.
Dez Built 2nd January 2017, 07:13 AM Thank you everyone. Ok Bob I will scrap the cyclone idea. Currently I do get some bad leaks around where the plastic collection bag gets attached. I'm not sure how I am going to fix this. Maybe a strip of foam glued to the metal bag housing might help seal it better.
Am I safe to assume that buying a pleated filter for the top is going to be more beneficial that the needle felt bag I currently have??
TinyTool 2nd January 2017, 10:38 AM Lappa, photo's as requested. Hope they make sense to you.
BobL 2nd January 2017, 10:53 AM Thank you everyone. Ok Bob I will scrap the cyclone idea. Currently I do get some bad leaks around where the plastic collection bag gets attached. I'm not sure how I am going to fix this. Maybe a strip of foam glued to the metal bag housing might help seal it better.
The bad leaks that are clearly visible are indeed often from rucking of the plastic collection bag around the bag housing.
Adding a packing material like a foam so that the plastic bag has to be stretched over the foam will help.
The problem with plastic bags is they develop tiny invisible pin pricks from chips rattling around in them or being battered by the swirling air against the bag support frame and these leaks cannot always be seen.
There really is nothing that can be done to prevent leaks - they are inevitable, so locating, or enclosing and venting, the DC outside is the only safe way.
Am I safe to assume that buying a pleated filter for the top is going to be more beneficial that the needle felt bag I currently have??
Yes the pleated filter gives a significant improvement in flow and the filter will last longer between cleaning.
However I would not decrease the servicing interval of the filters. Servicing filters is a PITA but short of going to a large cyclone there is no alternative.
Lappa 2nd January 2017, 12:00 PM Tinytool. I was referring to Dex Built's post " see the attached picture of the cyclone I had in mind" but I appreciate your photos as it's great to see how other people approach dust problems :2tsup:
Muchacho 2nd January 2017, 01:27 PM Hi Dex.
Your plan to ditch the filter and replace it with a cyclone venting outside is potentially a good solution. I have posted a couple of threads with how I built my cyclone with a modified 2HP fan. There's also results of testing carried out showing the resulting air flow performance which is as good as, if not better than a modified dusty.
BobL 2nd January 2017, 04:39 PM Hi Dex.
Your plan to ditch the filter and replace it with a cyclone venting outside is potentially a good solution. I have posted a couple of threads with how I built my cyclone with a modified 2HP fan. There's also results of testing carried out showing the resulting air flow performance which is as good as, if not better than a modified dusty.
The OP needs to be aware that this cyclone is not a commercially available product.
Dez Built 2nd January 2017, 08:15 PM Thank you. I will make those changes
Muchacho 3rd January 2017, 06:23 AM The OP needs to be aware that this cyclone is not a commercially available product.
The point I was trying to make is that building a cyclone is a viable option. There are a number of wwf members who have done this.
Im happy to answer any questions about building diy cyclones or purchasing one of mine.
DaveVman 6th January 2017, 02:57 PM If i had a 3hp dusty, then could I have a cyclone?
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BobL 6th January 2017, 04:07 PM If i had a 3hp dusty, then could I have a cyclone?
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Maybe have a read of this post.
http://www.woodworkforums.com/f200/improving-machine-cabinet-dust-ports-187936/6#post1999772
To efficiently separate dust and operate with minimal restriction the cyclone has to be designed and made to match the impeller.
Maybe have a read of this http://www.woodworkforums.com/f200/basic-tests-2-3-cyclone-3hp-210632 to see what happens when this is not done.
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