Thien baffle with 3HP unit? Does it work?

[Lou Stags]

In another thread, a fellow creeker gave some feedback that he thought this 3HP unit from grizzly was "too powerful" for the Thien baffle. The idea was that the dust collector was pulling air too fast through the Thien baffle, rendering the Thien baffle not very useful.

http://www.grizzly.com/products/3-HP...eries/G1030Z2P


Has anyone out there used a Thien baffle with a similar sized dust collector (or larger)? How did it work?

Thanks!

[david brum]

Hi Lou

It was me that had the 3 hp DC with baffles. It wasn't a Grizzly, although very similar. I was really surprised when I went to all the trouble and expense of making and installing baffles and filters, and it didn't work. The filters clogged almost immediately, nullifying all of my efforts. It honestly wasn't much better than running the thing with no baffles.

In contrast, I had a baffle and pleated filter on a 1.5 hp DC, and it worked great. I assumed I'd be able to apply the idea to a bigger DC, but no dice. The Thien baffle relies on a certain range of airflow parameters which are exceeded by bigger DCs. Too bad, because it would be a great solution otherwise.

[Phil Thien]

3-HP single-stage collectors are not all that common, I imagine, based upon my reading here and elsewhere. All of the units I've seen have had two rings, with room for four bags. And I do know of a few that are running baffles on these with no problem.

The key is having the two rings, so the air volume from the flower is /2 and the baffle works just as it would on a unit with a 1-1/2 HP blower.

Does Grizzly make a unit with only one ring and a 3-HP blower? I can't imagine that would work well under any scenario, as resistance is proportional to the airspeed squared. So I'd worry that you'd lose a lot of airflow by trying to combine a 3-HP blower with a single ring.

Most of the people that have had problems tend to have units with goofy rings, where the funnel is upside down or the entire ring is upside down. A few have simply broken the spot welds and reattached the funnel correctly.

Wade (above) is correct. When the blowers get larger and more powerful, they have to be combined with larger and larger cyclones. Like he said, there is a reason cyclones are so large. Take, for example, the huge cyclones you see at mills. They probably have 15-25 HP motors, large blower wheels, and the cyclone has to be proportionally larger to accommodate the huge volume of air that is being handled.

[Alan Melbourne]

i am using a 3hp startrite dust colecter. i have a 6"top hat design thien baffel. it works great. im verting out side but never seen any dust in my shop when it was venting inside with no filter (during testing)

[David Kumm]

Phil, do you see much benefit for your baffle with a bag or mainly for cartridges? Chips in cartridges are a bad idea but not so much much in bags.
What is your take? Dave

[Ryan Mooney]

i am using a 3hp startrite dust colecter. i have a 6"top hat design thien baffel. it works great. im verting out side but never seen any dust in my shop when it was venting inside with no filter (during testing)

Alan, out of curiosity - what is the dimensions/layout of your setup? Would be interesting to see the same info from Wade where it didn't work (and maybe we can determine why, nominally the startrite claims a higher CFM than the grizzly, so they are within the same vague handwavey range anyway).

Naively it seems plausible that you can scale up the size/layout of the baffle design to account for the extra airflow. Anecdotally it seems that several people have managed to so it would be pretty interesting to see what was different in those cases.

[Ryan Hellmer]

With dust collectors, everything needs to be scaled according to volume of air moved. On the Thein baffle, the collecting drum must permit the stream of air to slow down to a point that the dust is no longer suspended. Therefore if you use a baffle system designed for say a 1000CFM blower and up the air movement to 2000CFM, the air in the separator will only decelerate half as much and particles will remain suspended. Make it proportionally bigger and the concept should still work.

Ryan

[Phil Thien]

Phil, do you see much benefit for your baffle with a bag or mainly for cartridges? Chips in cartridges are a bad idea but not so much much in bags.
What is your take? Dave

I only mentioned four baggers so people would know the configuration I'm talking about. I agree with you that the baffle's biggest contribution is keeping cartridge filters clean.

The progression typically goes like this: People buy one or two beautiful Wynn cartridge filters, for a single-stage DC. Then they get them plugged about two or three hours later. Then they spend about an hour getting them clean again. Then they look for a solution to prevent them from plugging again. And then I've got them, LOL.

[David Kumm]

Phil, I think Wynn recommends your baffle or something similar when he sells cartidges for what I call baggers. Without your mod or something to help direct chips down they are about as bad design as the old cyclones with the filter on the inside. Dave

[ian maybury]

Hi guys. It's a bit of an interesting topic this question of cartridge filters blocking up.

I've not experienced it (except in the case of a bagger), but thinking about the details it seems like it might be the fine dust that causes the problem rather than the coarser chips. As in maybe the air passes through chips pretty well?

The reason I mention it is that I'm pretty sceptical as to whether even a cyclone can do a great job of capturing the fine dust. Against that it does seem that people don't suffer problems with them.

I guess I'm wondering how soon I might need to clean the filters on my Pentz/Clear Vue system. On the positive side while it's not done a lot of work it's been used steadily for months now and shows no obvious signs of slowing. (I still have to install some sort of flow or pressure measurement)

What's been your experience of the reality on this?

ian

[Phil Thien]

I guess I'm wondering how soon I might need to clean the filters on my Pentz/Clear Vue system. On the positive side while it's not done a lot of work it's been used steadily for months now and shows no obvious signs of slowing. (I still have to install some sort of flow or pressure measurement)

What's been your experience of the reality on this?

ian

Maybe too many variables to know.

Many people install a differential pressure gauge to "keep an eye" on their filter stacks.

I've been in some "show shops" where hardly anything is ever made, their filters NEVER need cleaning, LOL.

Steve Knight does a ton of CNC, and uses a Clearvue. He gave up on cartridge filters and switched to a plenum and bags, because he said too much in the way of fines made it past the Clearvue (plugging the cartridge filters).

I've been in small but busy commercial shops where they just clean the filter once a week or once every two weeks, using compressed air. I've had some tell me it is easier to keep them clean like this, than letting them get too dirty before cleaning. I think that makes sense.

But those differential gauges (Dwyer makes them) are probably a pretty wise investment, IMHO. That way you don't overclean (and risk damaging the filter), and don't risk getting the filter too packed, either.

[David Kumm]

Ian, the bad thing about chips in the cartridges are that they can tear up the fibers thus the filtering. I run my system on a vfd that displays amps all the time. When the amp draw on my shaper gate goes down a few tenths I blow off the cartridges. Sanding is the only thing that gets through the cyclone but I use a big bagger on the wide belt so it is only the edge sander now that goes through the cartridges. They only need air about once a year. Overfilling the cyclone drum is the worst thing ever though. Really try to avoid that. The Wynn filters have such a tight pleat that chips don't stick like they did on the old spun bond cartridges. Dave

[ian maybury]

I'm not quite sure David how my cartridges will do - they are Donaldon nanofibres from the UK. I built a filter cabinet set up for them so that the air flows from outside to inside as is normal for cartridges - this hopefully will ease the cleaning.

Thanks for the info Phil - I'm not too surprised that with heavy usage that enough dust gets carried over to require cleaning. I guess as ever with these things the question is to get at some hard data - how much/how often. It's not something that seems to get mentioned for whatever reason.

I've taken step (1) in that I've bought a photocell and LED light to build a 'bin full' warning set up - complete with flashing orange beacon in the workshop next door! Next up may be a Dwyer gauge....

ian

[Lou Stags]

3-HP single-stage collectors are not all that common, I imagine, based upon my reading here and elsewhere. All of the units I've seen have had two rings, with room for four bags. And I do know of a few that are running baffles on these with no problem.

The key is having the two rings, so the air volume from the flower is /2 and the baffle works just as it would on a unit with a 1-1/2 HP blower.

Does Grizzly make a unit with only one ring and a 3-HP blower? I can't imagine that would work well under any scenario, as resistance is proportional to the airspeed squared. So I'd worry that you'd lose a lot of airflow by trying to combine a 3-HP blower with a single ring.

Most of the people that have had problems tend to have units with goofy rings, where the funnel is upside down or the entire ring is upside down. A few have simply broken the spot welds and reattached the funnel correctly.

Wade (above) is correct. When the blowers get larger and more powerful, they have to be combined with larger and larger cyclones. Like he said, there is a reason cyclones are so large. Take, for example, the huge cyclones you see at mills. They probably have 15-25 HP motors, large blower wheels, and the cyclone has to be proportionally larger to accommodate the huge volume of air that is being handled.

Thanks for chiming in on this thread Phil. It would be interesting to do some controlled testing with your baffle design. I would assume a top hat design should be able to scale to handle different size machines by altering the height and/or diameter of the top hat?

Hmmmm..... now that I think about it a bit.... Bare with me as I am a newb, but from what I have read, when you use a larger duct, the speed of the air decreases. I am sure this has been thought of or tried before but have you (or anyone else) attempted to "step up" the duct inlet just before it enters the top hat? If you were running a 6 inch main that stepped up to 8 inches right before the inlet that would slow down the air speed. With a bigger unit like the grizzly 3HP double bagger linked above, that may help to slow down the fpm enough so that a lot of dust does falls out of the airstream (and solves the problem David mentioned he had with his 3HP unit).

Run a 6 inch main, step up to 8 inch for the inlet, and the outlet is back down to 6 inch. What do you think? Would this approach help all Thien baffle setups to drop more dust out of the airstream? Would it slow down the air too much or alter the airflow inside the baffle such that dust would no longer fall through the drop slot?

I know I am just some star-eyed rookie that is probably bringing something up that has been thought of and tested a million times over, but I am having fun thinking about this stuff and learning as much as I can. Thanks to all for the discussion, it is incredibly helpful as I try to learn and make a good dust collection decision.

[Lou Stags]

Anecdotally it seems that several people have managed to so it would be pretty interesting to see what was different in those cases.

Your theory sounds very plausible to me. Just imagine I built a Thien top hat design for my HF 2HP DC that went over a "bucket" that was 15 FEET in diameter. I would assume it wouldn't work very well unless I rigged up a 375 horsepower hemi-powered MEGA-COLLECTOR!