Bill Pentz and Cyclone Test

[Jay Albrandt]

I feel like I won the lottery! Bill Pentz came and evaluated my dust collection system and shop today. I can't believe how much time he invested (over 3 hours) and how thorough he was.

He started with an overview of the process, what he was measuring, and why. Next, he inspected all of the transitions to my tools and made many recommendations. Next, he tested the air outside of my shop for an ambient baseline, and then the shop air before running any equipment or the opening of any doors. Next, we fired up the cyclone and tested the air without cutting anything (my filters exhaust inside). The next test was done after cutting a 3 foot long piece of MDF, 18 times. Finally, the last test timed how long it took for the air quality to return to the baseline measurement.

What I learned: (Please keep in mind that I am a layperson and I am trying to process and regurgitate a TON of information).

1. All dust hoods and guards must do two things: They MUST be an effective physical barrier to dust being spewed away from the blade, and thus away from the air collection stream. If you don't have this first, then no matter how much CFM you have at the tool, you simply are not going to catch the harmful dust.

2. There was, is, a significant residual dust problem with my shop....meaning that I haven't been in there for two days prior to the test and there was enough total suspended particles (by weight) that I was almost halfway to requiring a mask, and I had 100,000 more particles in the 0.5 micron range than the outside air! Eeeeek!

3. I learned that my filters do an excellant job of cleaning the air in my shop. By running the cyclone and not cutting anything, the filters reduced the total particles from comment #2 by half.

4. After cutting the MDF, the particulate matter (both in size and weight) doubled to just past the point of requiring a mask for my safety. This means the cyclone and filters are doing their job, but my dust hood needs some improvement.

5. By just opening the garage door, and putting fans in the back door, I reduce my exposure significantly.

6. For those of you who have a Pentz' design cyclone. I have the 14" impeller and my real world, direct measurement came out to be 1,099.564 CFM, with the 5hp Lesson motor at only 10.8 amps. That means I can upgrade to the 15" ClearVue impeller and get another 300 CFM when I expand my shop and still not overload the motor. smirk!

I hope this is helpful.

Jay

[Jim O'Dell]

WOW!!! That is cool!! Makes me wish I lived in California so Bill might visit my shop....Nah.
That is a very good test. I like the idea of measuring before you did anything to get the base line, and also to test outside.
You say your filters did a very good job...what filters do you have? I'm thinking seriously about exhausting outside as I don't condition the air in the shop. but there might come a day when I will need to filter it and keep the air inside.
Thanks for the post! Jim.

[Jan Williamson]

Jay,
I have the Clearvue, some recycled filters and muffler in a sound board lined closet. I got similar results although your CFM's were little higher that mine. I have a not so ideal duct system (newbie), and some leaks around the blast gates , but still at over 900 CFMs still over what the biggest dust makers need (with proper hoods). I like the idea of having a fan in the back if the garage (on nice days), and blowing out the shop every week or so too. Bill gave me lots of sound advise for improvements. I am extremely satisfied with my system, and feel lucky to be included in Bill's studies.
Did he get any chocolate chip cookies at your place?

[Jay Albrandt]

Did he get any chocolate chip cookies at your place?[/QUOTE]


Jan,

No cookies!...He wouldn't let me. He did brag about the elk you served though. I offered to have anything on hand for him and of course he politely refused. I mean the guy drives down here all the way from the Sacramento area to test my shop for free, and the only thing he would let me do is buy him lunch?!!!! Wow!

He said you have a beautiful set up.

Jay

[J. Scott Chambers]

Based on your statements #3,4, and 5 above, I'd say your filters are working, and it's your hoods that need improving. I don't see how venting outdoors will cure that, other than diluting the air with lower particle count OA.

[John Renzetti]

hi Jay, Thanks for the informative post in a real life situation. MDF can be nasty stuff. If you are going to cut a lot of this stuff then the investment in those .2micron Torit filters would be worthwhile.
take care,
John

[Russ Massery]

Like Jim I'm envious, Great to know mine has the 15" impeller. Standard now now on all Clearvue's. But like Bill said even the best equiptment doesn't work well with out proper dust hoods. Wish I could have Bill check my system out. Bill if your ever in the Great midwest. The SWMBO makes great chocolate chip cookes.

[Bill Pentz]

My thanks to Jay and his lovely wife for having me come visit and our nice lunch together. Jay has a shop that he is using to rebuild a home and folks he is not just good, but doing incredible work. If I had a tenth his energy some of my backlogged projects would be getting done.

This last few days was quite an adventure in terms of testing as I managed to log just over 1,100 miles since Thursady and look at a few shops. Without mentioning any names how about a 60x40 shop with tons of refurbished old iron, meaning a 1000+ pound lathe and more? Came home and saw my lonely tools just sitting waitng for me to rebuild ducting, install another cyclone etc. and think I am going to go rest up for a while.

Test results are showing some very consistent things. Those who setup their shops with a regular through airflow (open big door in front and fans in the rear) have no significant buildup of residual dust, but every one who closed the doors had had residual dust problems regardless of dust collector, cyclone, filters, or air cleaner. Evern more imporatnt, every shop I've tested no matter how good the airflow ended up with problems if their hoods did not do a really good job of blocking, trapping, and collecting the dust. Likewise, even with good hoods, those systems that did not move enough air also had problems with very high dust levels following our test cuts. I just cannot emphasize enough that our hoods have to block, control and capture the dust plus we need to move the air and then get rid of that fine dust. The only other issue this testing is showing is the huge numbers of very fine particles that are going through the filters along with a few failed filters that woodworkers thought were working just fine.

bill

[Alan Simpson]

The only other issue this testing is showing is the huge numbers of very fine particles that are going through the filters

OK now I'm confused... you spent most of your post talking about how the residual dust is caused by insufficient airflow and/or poor dust hood design allowing dusto to escape and never reach the DC.

How do you make the jump from that long-winded explanation to a "huge number of very fine particles" going through filters???

With all of the controversy and accusations about Filter performance of late, I would hope you would go a little deeper into explaining your statement rather than just throwing it out there like you did.

What kind of filters??? Bags? Cartridges??? Rated filters??? What do you consider "Very fine particles"??? What do you consider a "huge" amount??? And probably most importantly, how are you differentiating between dust escaping from the hoods and dust escaping from the filter?

[Phil Thien]

OK now I'm confused... you spent most of your post talking about how the residual dust is caused by insufficient airflow and/or poor dust hood design allowing dusto to escape and never reach the DC.

How do you make the jump from that long-winded explanation to a "huge number of very fine particles" going through filters???

I think, if the filters are deficient, then the last phase of Bill's test (waiting for a return to safe levels with no cutting but DC running) will take forever or will never happen. It is during this phase that they are essentially using the DC as an air filter, and the suitability of the hood is pretty much out of the equation.

It is possible for the hoods to also be deficient and for that to be detected earlier by the detection of larger particles during the cutting tests. Larger particles suspended in the air would indicate that these particles are getting past the DC altogether.

[Alan Simpson]

I think, if the filters are deficient, then the last phase of Bill's test (waiting for a return to safe levels with no cutting but DC running) will take forever or will never happen. It is during this phase that they are essentially using the DC as an air filter, and the suitability of the hood is pretty much out of the equation.

It is possible for the hoods to also be deficient and for that to be detected earlier by the detection of larger particles during the cutting tests. Larger particles suspended in the air would indicate that these particles are getting past the DC altogether.

Excellent point Phil. Of all the people who have reported their results of Bill's testing, they all mentioned how quickly their DC returned the air quality to the baseline after cutting ceased (by leaving the DC on). To me, that directly contradicts Bill's claim that "this testing is showing the huge numbers of very fine particles that are going through the filters". As you stated... if this were true, the air quality would NEVER return to the baseline.

[Phil Thien]

Excellent point Phil. Of all the people who have reported their results of Bill's testing, they all mentioned how quickly their DC returned the air quality to the baseline after cutting ceased (by leaving the DC on). To me, that directly contradicts Bill's claim that "this testing is showing the huge numbers of very fine particles that are going through the filters". As you stated... if this were true, the air quality would NEVER return to the baseline.

Right, and I have a problem with citing values like "huge numbers" on so many levels it isn't even funny.

[Jim O'Dell]

Excellent point Phil. Of all the people who have reported their results of Bill's testing, they all mentioned how quickly their DC returned the air quality to the baseline after cutting ceased (by leaving the DC on). To me, that directly contradicts Bill's claim that "this testing is showing the huge numbers of very fine particles that are going through the filters". As you stated... if this were true, the air quality would NEVER return to the baseline.

Do I gather from your post, then, that you feel the problem is at the point of collection? If so, I think that is a good point. (If not, let me make that point here ) I know Bill Pentz devotes a pretty good section of his site to pick up hoods. Other sites touch on it as well. So, who has a good handle on pick up hoods for different types of machines? I'm really amazed that with the prolifferation of cyclones in todays market, that more of the distributors don't push for 5", or prefferably, 6" hook ups on their table saws, jointers, bandsaws, etc. And while there are some aftermarket pick up hoods for mitre saws and contractor saws and such, I don't see manufacturers stepping up and developing these for their specific tools. I'd like to see even adjustable air inlet holes via a slide like a blast gate to adjust for the air flow within a specific tool. (To collect the dust and chips, you need air flow, not suction)This should be easy to do on a TS or Jointer. Properly positioned, it would allow the air to then flow across the Blades(s) and on into the pick up tube for optimum collection.
Anyway, just some thoughts since I'm house bound today. Jim.

[Don Baer]

Robert,
I can't speak for the other question because I wasn't with Bill doing the testing but I can speak about the equiptment he is using. It is a GT 531 Particulate counter from Met One Instruments. The reason I know this is because Bill asked me for a recommendation of the types of instrument to use and this is the one I recommended. I met the folks at Met one at the last AIHCE show in Chicago and found that it is just the ticket for doing portable survey work like Bill is doing. If you would like more information feel free to PM me or go to there web site.

Just a side note I don't work for Met one I am just a happy customer.

[Phil Thien]

Robert,
I can't speak for the other question because I wasn't with Bill doing the testing but I can speak about the equiptment he is using. It is a GT 531 Particulate counter from Met One Instruments. The reason I know this is because Bill asked me for a recommendation of the types of instrument to use and this is the one I recommended. I met the folks at Met one at the last AIHCE show in Chicago and found that it is just the ticket for doing portable survey work like Bill is doing. If you would like more information feel free to PM me or go to there web site.

Just a side note I don't work for Met one I am just a happy customer.

Perhaps you can answer a simple question for me, given your familiarity w/ this device. Are the numbers being quoted per cubic centimeter or cubic meter or ?

TIA,
Phil