Jet Dust Collector – V Weave – Work?
Is there an engineer-type who can explain the Jet (other brands also) pleated filter for dust collectors.
Such as http://www.woodcraft.com/family.aspx?FamilyID=60039
On the Rockler site, it says:
THE SOLUTION TO FILTER CLEANING
New Canister Filters Have Over Six Times The Filtering Capacity of Standard Filter Bags! Filter Cleaning –
With standard filter bags you will usually need to remove the bag and turn it inside out to really clean thorougly, causing fine dust particles to be sent airborn. With the canister filter your simply turn the handle on top, rotating a cleaning flapper inside the canister. This shakes the dust from the filter letting it fall directly into the collection bag. The “V” weave of the canister filter features up to six times more filtering area than filter bags
______
Now, I understand there is a lot more surface on the V weave IF, IF, IF, there is no dust clogging up all the Vs.
But, the dust DOES clog up all the Vs. Which means, there is actually less space than if you were using a bag.
Is my brain clogged up? Am I missing something? I agree the theory is correct. Everything in reality tells me in practice it does not work as advertised.
Anyone have any practical experience or technical explanation? Pro or Con?
Thanks,
Alan – planesaw
Replies
I have the JET DC1100 with the canister and yes, it does work very well. I was a little concerned with it's overall size because it is shorter than the bag it replaces but with the pleating, there is way more surface available for filtering. Also, the "hands" that clean the inside surfaces are not only a cool idea, they work! Plus, you can use an air hose to blow from the outside in (don't have to take it off and have a dust explosion in the shop) to clean dust back out the way it came in.
I have a review of this machine at the link below with a video that shows the cleaning hands inside if that would help.
http://www.newwoodworker.com/reviews/jetdc1100rvu.html
Tom Hintz
Because there is always more to learn!
"But, the dust DOES clog up all the Vs." I think you're assuming the dust clogs the V's all the way to the inner level (e.g., filling the valleys to the "top" so-to-speak). You'd have to be incredible neglectful for this to happen.
I went out and pulled the canister off of my JET to look at the pleats. I have been working a bunch of 2'"-thick oak and he DC has been on all but constantly the last couple of weeks.
The flapper hands are doing their job because while you can see some dust in the pleats, it is a thin coating and not a build up. There is no caking or piles of dust to be seen.Tom Hintz
Because there is always more to learn!
Reading Alan's first post, I'm just thinking he must be envisioning those pleats completely filled, thereby making the inside of the cylindar flat -- and smaller than a bag. You and I spin the flaps. Maybe he doesn't plan to?? ROFL!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Boy do I need some of those flipper flaps for my shop vac. ;-)Work Safe, Count to 10 when your done for the day !!
Bruce S.
"Boy do I need some of those flipper flaps for my shop vac. ;-)" I know what you mean! I use the DC to clear the shop vac filter occasionally. Mostly, I spend alot of time gently tapping the vac filter on a rock somewhere, LOL!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
All,
My question comes from reality - including spinning flaps!!! My question is not coming from theory. It is coming from some practical experience.
I bought a well taken care of, lightly used Jet filter from a friend and put it on my Jet DC (model I referenced earlier). When I got it home and out of the box, it was packed with sawdust. Simply moving it around dislodged some dust. Turning the "flappers" dislodged more.
BUT, BUT, there was still considerable dust in the Vs. Turning the flappers still left a ton of sawdust. I had to use an airhose on the outside and vacuum with a brush on the inside.
While one has the DC on, the dust is filling in the Vs. (Yes, I understand that when you turn it off, turn the flaps, a lot of the dust falls away from the filter). But, while you are working with the DC on, the filled in Vs are reducing the amount of filter available for the air to pass through, thereby reducing the suction capacity of the DC.
Stuff from the jointer or planer is larger. Not quite as much of a problem.
But, dust from the table or bandsaw, and particularly from a sander is much smaller. The small stuff packs the Vs. And much of it does not dislodge simply because the flappers are turned.
Alan - planesaw
Edited 6/9/2007 10:34 am ET by Planesaw
It'll take someone with infinitely more math and physics chops than I have to answer detailed questions about the "real" surface area, but I can tell you that the only time I notice a significant decrease in my Jet cannister's DC performance is when I let the bag get too full. When using a 4" hose (planer, jointer, table saw), as long as the swirling tornado of sawdust/shavings in the bag is about 4" below the rim of the bag holder, it sucks just great. If it gets so full that the top edge of that swirl is nearly touching the rim, it's too full and doesn't suck so good.
I'd guess that investigating your question would involve figuring out how much air still flows through the dust that's in the V's. How regularly did your friend "flap" the filter? forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Planesaw,
Please keep in mind that some dust on the filter surface is a GOOD thing.
It decreases the size of the particle that can pass through the filter.
Remember that the bag filters let a cloud of small particles through untill a build up of fine particles on the inside increase the filtering. The same is true for the canister.
Filtering comes from a variety of methods. The torturous path through the filter eliminates particles that a) hit the filter media b) lose momentum and fall prey to gravity c) are too large to pass through the media d) are attracted to the media more strongly than their momentum to pass by (electrostatic charge effect) and so on.
Having a perfectly clean filter is only a good start, a layer of particles over and through make for a better filter.
At some point, you are into an unacceptable reduction in flow, and then some cleaning is required. It is a balancing act between particle capture and gas flow.
I believe that the flappers reduce the particles sufficiently for good gas flow, whilst retaining sufficient particle capture.
Dont over analyze this to death - the flappers work as advertised, spin the handles once before each bag change and get back to having fun with the wood!
Mike
"...spin the handles once before each bag change and get back to having fun with the wood!" So you're advocating not doing periodic "flapping" between bag changes?? I'd be concerned about a decrease in air flow, especially if a great deal of table saw, miter saw, or sanding product was being collected.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Forestgirl,
"once before each bag change" - one time, JUST before changing the bag.
Sorry if I wasnt clear.
Mike
Mike, I'm getting sucked into this whole over-analyzing thing. Sorry. I don't understand why we (us cannister owners) wouldn't want to Flap periodically between bag changes, as an ordinary precaution. I do so, maybe 3 or 4 times, with the idea that if I don't clean some of that dust out of the pleats periodically, the air flow is liable to diminish.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Forestgirl,
No problem, I dont think you can over flap the filter, but I dont think it is NECESSARY more than once, and for convenience, I suggest it to be just before you change the bag. Get in the habit as part of the changing procedure.
Basic point was that clogging of the filter was not a major concern. Even when packed with dust, it will still work - see your shop vac for example - still sucking hard when the bucket is full and the filter is packed.
To go off on another tangent, to my mind the real advantage to the canister filter is the clear plastic bag that lets you see when the bag needs changing.
(its also fun to watch the chips circling around, but then, I am easily amused (grin))
Mike
"see your shop vac for example - still sucking hard when the bucket is full and the filter is packed." Hmmmmm, not my "shop vac" -- one is a small Shop Vac, the other the biggest Craftsman made in the 1980's Neither one likes to have a super-full filter (both HEPA's) or a fullish tank.
"...the real advantage to the canister filter is the clear plastic bag that lets you see when the bag needs changing." I see two other, more important (IMHO) reasons: Better filtration, and the ability to get rid of that stuff without getting covered with dust (handling a cloth bag). Even though I don't tie and toss the bag (keep using it, several times), even transferring to a yard-bag, I don't get much dust flying about.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Hi Planesaw,
Maybe the previous owner milled some green or wet wood that caused the filter to really " cake " on the inside.
Paul
colebear...
Good point. I'll have to watch how much dust "sticks."
Alan - planesaw
Alan,
You are correct. But if the dust fills up the valleys of a cartridge filter, that same dust would also fill up the microscopic nooks and crannies of a bag filter as well.
In other words, because of the greater initial surface area of a cartridge filter, you can not maintain a cartridge for a longer period of time than you can not maintain a bag filter.
Wilbur
wilburpan,
Understood (do you have one to many "not"s in there), but more of the surface area of the Vs get filled quicker than the bag. In that line of thinking, the bag should come out ahead as a surface area.
However, better to have to clean a filter letting only 2 microns through than a bag letting 30 microns through.
Alan - planesaw
"do you have one too many "not"s in there"Hi Alan,No, just trying to be cute with my post.This is one of those questions that probably can't be answered definitively without grabbing a bag and cartridge filter, and making measurements. We can philosophize all we want, but hard numbers would settle this quick.But I would still bet on the greater surface area of a cartridge to over come the "filling in the valley" effect. And this is coming from someone who has a bag filter on his dust collector.Wilbur
Wilburpan,
I have both, although I am just starting to use the pleated filter. If we are simply pushing air through the filter, I would agree the filter wins over the bag.
Maybe with some more experience I'll be able to answer my own question.
Alan - planesaw
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