Woodworking power tools – such as saws, routers, and planers – create an obscene amount of dust and debris. Woodworkers will often use shop vacuums or specialized portable dust extractors to help manage this, but filters clog quickly, bags fill up fast, and canisters require frequent emptying.
A clogged filter or filled bag can also lead to loss of suction power.
What does a Cyclone Add-on Do?
Working with wood produces fine dust particles, coarse medium-sized particles, and large debris such as chips and shavings. Cyclone add-ons separate and collect a large proportion of medium and large-sized dust and debris, preserving the suction power and performance of the attached vacuum or extractor.
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Cyclones are not 100% efficient, so eventually filter maintenance or a fresh bag would still be needed.
Higher-end shop dust collectors come with 2-stage filtering built-in, and the cyclones typically work in the same manner as those that you add to portable vacuums.
How do Cyclones Work?
Generally, all cyclone separators feature an indirect path from hose intake to hose outlet. That is, airflow and particle travel is not a short distance from inlet to outlet. Airflow starts at the inlet and follows along a downwards helical path until it reaches the bottom of the conical section. The vertical upwards return flow towards the vacuum outlet starts at the center of the cyclone near the bottom.
The heaviest debris – wood chips, shavings, and such – quickly fall to the bottom of the separator. These larger particles collide with the cyclone walls, lose speed, and gravity helps pull them down towards the collection container.
Lighter and medium-sized particles continue on the helical airflow path along the walls of the cyclone or separator. At the bottom of the cyclone the conical section helps to further separate medium-sized particles from the airflow.
Some lighter particles will remain in the helical airflow, some will be separated with the medium-sized particles. The smaller radius of the taper means a greater wall-hugging force that keeps the smaller particles away form the center.
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At the bottom of the cyclone taper, a portion of the lighter particles will drop to the collection container but some will be drawn up towards the vacuum source.
Usually it is only some of the finest particles that carry through to the dust collector or shop vacuum. But if the intake rate is too quick, more dust will make it to the vacuum.
Cyclone separators might lead to a slight reduction in vacuum power, but even if by a noticeable amount this is outweighed by the benefits. The amount of reduction would certainly be less than the drop that would be caused by a quickly-clogged filter or collection bag.
Cyclone Separators vs. Lid Separators
A lid separator, which is often placed on top of a 5-gallon bucket, garbage container, or other vessel, is better than no separator, but well-designed cyclone separators are generally better.
Both filter larger debris, but cyclone separators sometimes do a better job of separating finer and medium-sized woodworking dust particles.
In theory cyclones are better, but because both types of products have their benefits and trade-offs it’s unfair to say that one is better than the other in practice.
jesse
This post totally ‘sucks.’
Mahalo
Well played, Jesse, well played.
I still think that the real answer to the question “How Does a Cyclone Separator Work?” is: “Magic”.
hangfire
Yeah, Magic. I too struggled with the explanation until I finally figured it out.
Cyclonic separation works by using the greater mass and momentum of the particles versus that of the air. By constantly changing the direction of the air, particles (sawdust, etc) tend to continue straight and fly out of the higher speed airflow into a collection mechanism.
A simpler non-cyclonic separator (to make, and to understand) can be made at home with a pipe in the top of a large container, where the combined air/waste stream goes straight down a long narrow center pipe. Momentum and gravity carry the heaviest particles straight into the collection bag at the bottom. The cleaned air reverses direction and travels at a lower speed (due to the larger volume of the container compared to the pipe) upwards along the outside of the pipe into the vacuum fan collector at the top.
A diagram would really help here… but a single 180 degree turn as described would remove lots of heavy sawdust particles, but tend to stir up and recollect fine particles. Thus the invention of the cyclonic version, which keeps turning, and turning, and turning, until even some very fine particles are thrown off.
Clear as mud?
Steven B
I have the Dust Deputy (the same one in Stuarts image). It is absolutely amazing. I may blow dust out of the vacuum’s filter 4 times a year (and I may catch a few errant leaves in the vac canister) – the bucket just catches 99.9% everything. I just peel off the lid and dump the contents of the bucket – the operation takes all of 2 minutes. In a good weekend of planing, I’d empty the bucket 3-4 times and not even consider blowing out the filter in the shop vac. Before the Dust Deputy, I’d have to blow out the filter with every shop vac empty. Generally, the shop vac stopped effective suctioning (due to the filter) before the vac was filled. Even though the capacity of both the shop vac and bucket are both 5 gal – the Dust Deputy can be filled with slightly more stuff. The buckets are semi-translucent so you can tell when they are filled without needing to open the thing.
My setup is a 5 or 6 gal. Rigid Black Friday vac from several years ago. I built a base for it on casters, sandwiching concrete between two pieces of plywood to keep the center of gravity low. Where the casters went on the vac base, I use threaded eyebolts that go into T-nuts in the base to keep the vac from moving in the base. A top shelf holds a 5 gallon bucket that is bolted down. A piece of styrofoam in the bucket is used as a spacer, then the real 5 gallon bucket is placed inside of that. The spacer prevents the buckets from getting vac-locked together. The cyclone/lid goes on top of that. I then attached various PVC fittings to the top shelf around the buckets to hold attachments and the hose, and a plastic pipe holder for the extension parts.
I bought the kit with the lid, buckets, and spacer at Rockler several years ago with a coupon. They also sell just the cyclone and you are on your own with the lid and gasket. I also bought the Rockler clear shop vac hose (which is fantastic, BTW). I don’t think Rockler sells them anymore since they have their own cyclone.
What I don’t like about the Dust Deputy (relatively minor and setup dependent):
1. The Plastic lid they give you with the kit is pretty thin. I was hoping for a more solid lid, given that I’m pulling the cart around by the hose to go from tool to tool. This thinness also means that with vacuum, you can see it cavitate a bit, sucking the cyclone down. I wish the lid was thicker/more solid.
2. The ports are tapered, meaning there is very little friction-based contact with the hose. I’m sure that they did this so it would be compatible with the hoses that came with the shop-vac you are using, but I’d rather it had a more solid and secure fit for normal commercial hoses. The Rockler hose has a swivel built into it, and the addition of the hose clamp helps quite a bit. Like I said, I use the hose to drag the cart around, so it really shouldn’t be a big deal if yours is not mobile.
Charlie
I’m not overly wild about the Dust Deputy, especially the plastic one. It looks too flimsy and would probably become brittle over time. Plus where the vac hose hooks up, if your pulling it around by the hose I would think that it would tip over easy. I have a Delta 50-760 Dust Collector that I added an onboard Separator too that has a Thien baffle inside, it works beautifully. Infact it works so well that for my shop vac I built a 5 gallon Separator that also has a Thien baffle inside. Both can be seen in the website https://sites.google.com/site/deltacontractorstablesaw/
Charlie
For now I closed my website that shows the Separators. I’m no longer a Thien supporter.
Stuart
What changed?
Charlie
He runs a typical cult like woodworking related forum.
asghar
very clear and coceptual diagram