Dust Collector

[SARGE..g-47]

Cannister filters are easy to use as they have a turn-crank that loosens the compacted dust between the filaments. That saves the mess involved of turning a felt filter bag inside out and beating it to loosen the compact dust. And that fine dust gets all over everyting unless you are using dis-posable bottom catch bags.

But... in order to clean a cannister throughly, they need to be blown with compressed air. A majority don't, but they are defeating the purpose of having the cannister in the first place.

And there is no short-cut to not using a separator barrel with either a DC or a cyclone. The bag will fill so quickly that life becomes a pain cleaning out the main dust bag. With a separator the larger stuff goes in and you simply pull off the lid and dump it. The main dust bag that gets the smaller micron dust that passes through the separator can go months sometimes without servicing.

Regards...

[LarryG]

Cannister filters are easy to use as they have a turn-crank that loosens the compacted dust between the filaments.

Some canisters have this, but not all. Unfortunately the very popular Wynn mod for the equally popular HF 2HP DC is one of the ones that doesn't (but if it did, it would probably cost more).

[SARGE..g-47]

Greetings Larry...

And you are correct about cranks as I am beginning to find out as I am shopping a Cyclone at the moment. I think the turn crank can decieve some users in thinking that by "just" turning it, thye have cleaned the filter. IMO.. what is does is basically loosen the large compact between the filaments and save a lot of hand thumping. It does not really get rid of all the dust compacted and without any further steps the DC looses a degree of efficiency in both cfm and ability to get the majority of under 2 micron paticles that destroy your lungs.

And that's the deception I mentioned. Just because a machine has gathered the saw-dust you see visually, doesn't necessarily render you safe from those tiny particles. If that filter is not cleaned properly, it has lost some of it's ability to capture the small particles in the drop drum and will do nothing more than just re-circulate the excess it didn't capture. So.. I mentioned the point of blowing it out after you crank.

I have been digging into this matter for weeks and there is ton to absorb in what is efficient. Smooth walled metal pipe maintains more efficeincy than ribbed plastic.. large diameter pipe taken as close to the machine as possible before the reduction to fit the machine port.. etc., etc.. It almost requiires a degree it's beginning to appear. :>)

I am thinking of a 2 HP PS cyclone with 6" pipe. Just one 4 foot drop of metal pipe straight off the DC motor and impellor as my large machines are centrally located close to the center of shop where I will put the cyclone and they back up to it. Changing the ports on the 18" BS, TS, 8" jointer to 6" ports and the 20" planer has a 5" which will require reduction from the 6" straight pipe to 5". I will only have to run plastic pipe no more than 6 feet maximum to get to that 6" metal pipe straight 4 foot drop from the machine. So.. I get a run of no more than 10 feet for any machine with 6" ducting as I will only connect one machine at a time as I use them with a quick connect.

That should be enough to "suck your socks off" using a combination of 6" metal and 6" plastic pipe with a maximum of 10 feet away from the motor and 14" impellor. But.. I won't be decieved in thinking that no small particles are not going to get re-circulated back in the air "if I only turn a crank" on the filter every once in awhile and empty the cans. The filters that do the work of getting those under 2 micron particles will have to blown with compressed air to keep keep them efficeint and the enviroment healthy. Without doing so.. I will get all the stuff you have to sweep for sure.. but that is not what gets in your lungs and creates havoc in the long run.

Bottom line... take time and clean the filters on whatever set-up you have regardless of how elaborate it is as well as possible. Nice work is watered-down somewhat by the ability to not be around to enjoy it for as long as you could with a little extra effort!

Regards...

[LCHIEN]

Quote:
Originally Posted by SARGE..g-47
Cannister filters are easy to use as they have a turn-crank that loosens the compacted dust between the filaments.

Some canisters have this, but not all. Unfortunately the very popular Wynn mod for the equally popular HF 2HP DC is one of the ones that doesn't (but if it did, it would probably cost more).

All the DC manufacturers add-on or upgrade kits have the turn crank beater bar.
E.g. Grizzly, PSI, Jet, HF, and at least one-more I can't think of.

Most of the stuff sucked into the DC falls to the collection bag, but about 1% gets sucked up into the filter canister (which is pretty good considering 100% of the air goes out the canister filter. Having a Neutral vane helps keep the uptake to a minimum (e.g. the 1% getting sucked up) , but sometimes chips are sucked upwards into the filter - then get caught in the pleats of stiff paper filter. By "flapping" the pleats, the beater bars help make these and the fine dust get dropped down into the bottom bag where it will likely stay unless the bag is too full.

[Kristofor]

If that filter is not cleaned properly, it has lost some of it's ability to capture the small particles in the drop drum and will do nothing more than just re-circulate the excess it didn't capture. So.. I mentioned the point of blowing it out after you crank.

Being extra "caked up" will reduce the cfm, and may let more fine particles escape from the tool being used, but I don't think it's going to cause them to keep recirculating. I suspect it works just like the bags, where that fine dust in the filters actually improves the capture rate (of the filter, not automatically the whole system) at the cost of decreased airflow.

[LCHIEN]

Being extra "caked up" will reduce the cfm, and may let more fine particles escape from the tool being used, but I don't think it's going to cause them to keep recirculating. I suspect it works just like the bags, where that fine dust in the filters actually improves the capture rate (of the filter, not automatically the whole system) at the cost of decreased airflow.

good points
And since the filter has 6 or 10 or more times the filtering area, any caking will be that much thinner if it does occur. with less detrimental effect.
And not to mention the pleated paper filters filter properly even when clean compared to felt bags wich need some caking to achieve the cut point but by which time they have lost their low restriction and high cfms.

[SARGE..g-47]

Greeting Kristofer...

Having just read a ton of info in these DC's, I am not confident that I have it all sorted out yet as I have seen contradictions from several authors to other authors? I'm still puzzled as to what really happens once it enters the intake port.

As Loring stated, the clean air should re-circulate out the filter bag or cannister in the top and the fine, dangerous dust should settle to the bottom in the final drop can. If the filters are caked.. the air can't circulate back out because of the blockage. It has to reduce the cfm because the blockage allows no where for that air to go and causes back-pressure which in turn reduces cfm on in-take.

We know that what the machine is capable of taking in won't get taken in if cmf is reduced and the chips and larger saw-duct ends up on the floor with fine particles floating in the air.

So what happens to "what does actuallly get taken in with the reduced cmf remembering that the filters are clogged with compact? Where does the fine particles end up? Do they just compact in another layer to the back of the present compacted clog reducing cfm even further to the point that there is no cfm to speak of?

I don't know, but I would like too. I wish some of the authories to be would address some of this in simple layman's terms so we could have a true picture of the do's and don'ts with these DC's!

Until I understand "without a shadow of a doubt" (life used to be simple), I am just going to insure that I keep the filters cleaned well by blowing them with compacted air as the final step. But.. I would still like to know exactly what is happening. I think everone would agree on the reduced cfm, but what's the rest of the story? :>)

Regards...

[Kristofor]

Until I understand "without a shadow of a doubt" (life used to be simple), I am just going to insure that I keep the filters cleaned well by blowing them with compacted air as the final step.

That is of course the best way to go

Here's an illustration.

Take a spaghetti collandar. Put a handfull of sand in it. Almost all of it will fall through since it's smaller than the size of the filter.

Now put a handful of cornflakes in the collandar. Almost all of it will be caught by the collandar/filter. Now if you put a handful of sand on top of the cornflakes some will still leak out, but a fair amount will be "trapped" on top of the larger, but tightly packed corn flakes. Essentially the resistance of the filter has increased and now some smaller particles are being trapped

That's what dust loading does to a filter, it decreases the minimum size of the particles that it can catch, but it does so at the cost of increased resistance. This increased resistance reduces the amount of air that can pass through the filter in a given amount of time, so your CFM rate drops.

This may well allow more fines to escape at the point of manufacture but it doesn't mean that the the DC will recirculate them. So long as they're larger than the filter size, they won't make it through once they're sucked up, they just might not be sucked up in the first place.

The reason I said I was guessing that the canister filters would be similar to the bags is that I wasn't sure what part the geometery might play. With the fairly tight folds/pleats in the filter I'm guessing that caking has a disproportionatly larger impact on airflow than with bag filters, but it's not something I've tested or researched. Because..... I do what you suggested, many words ago, and blow my filter out fairly regularly

[SARGE..g-47]

Greetings Kristofer....

Not a bad analyzes of what takes place when the filters clog with the sand and corn-flakes comparison... and the bottom line derived of "clean your filters often" adds icing to the cake! :>)

Regards...

[Jeffrey Schronce]

I agree with looking at entry level PSI or Grizzly cyclone. Remote start, documented CFMs, and excllent prices on both the enntry level models. I vent outside so I got a Bridgewood 3 HP cyclone from Wilke. It is scary how much that thing sucks and I haven't even completed duct upgrades to 6" hose/connections.

[cgallery]

Yeah, I liked the colander analogy, too.