Neutral Vane in DC's??

[Jerry Olexa]

In my studying for a new Dust Control system, I've encountered "nuetral vanes". In both cases, the owner built one themselves and claimed increased performance significantly. What your opinion on these? necessary or desirable? Can you buy them rather than build? And what is their general function? Thanks in advance..As always, I value your input more than the mags, etc Jerry

[Jerry Olexa]

I'm cheating a liitle bit by reposting and moving to top of list, I know there are scholars/experts on this forum who know a lot more than I esp about "nuetral vanes" in a Dust Control system, I understand they are essential along w upgraded bags/filter plus separator. Anyway, my skills/patience @ working w metal are suspect so I'd like to find a source to purchase one. Any ideas? Thanks and promise I will not resubmit :confused:

[Chris Padilla]

Jerry,

No problem with the bump...I missed this post or would have responded. First, be sure to read this thread:

http://www.sawmillcreek.org/showthread.php?t=9933 I'm guessing you've seen this but just in case, what I understand is the neutral vane is the rectanglular inlet on the cyclone body. At the above thread, go to post #24 by yours truly and note the rectangular inlet in the last 4 pictures. Continue on and you'll see how the spiral/helical ramp sort of fits with the rectangular inlet.

My understanding is this allows a much less turbulent entrance of air into the cyclone body. Hope this helps you see how you might be able to make one or find a sheetmetal place to make you one.

[Brad Olson]

A NV is also used to keep air that has gone around the circle from crashing into incoming air. It also helps direct the flow of air downward into a cyclone to slow it down and drop out the dust/debris before going into the final filter.

Usually you have to make them. If you need a link to my website showing how I made one for the HF 2HP DC, let me know.

Bill Pentz has a good discussion of them on his website under DC modifications. Again let me know if you need a link

[Norman Hitt]

A NGV "IS" the Helical Ramp fastened to the outer walls of the main cyclone body, and as mentioned, is strictly to Guide the dust down, around and away from the inlet and allow the incoming dust to flow effeciently around and DOWN toward the bottom, without interfering with the new dust coming in the inlet.

A NGV is not always necessary, and sometimes even detrimental (as I understand it) to a cyclone's performance, depending strictly on the design of the body and cone of the cyclone, (proper ratios of main body diameter to height, cone length, etc), rectangular inlet vs round inlet with angle of inlet entry, (slightly down and tangent to the cyclone cylinder outer wall), and even the blower. From what I've read and in some user reports, it appears to me that an NGV is a compensating "Design Bandaid" to correct for design ratio discrepancies, (which in some cases are intentional, such as when a unit has to be designed with a shorter than optimum cone length and overall height, because of ceiling restrictions, etc.)

The "Wood Magazine" cyclone design, has been used many times as an example of this, as it was designed shorter than optimum, because they felt most folks home shops would not provide adequate ceiling heights for a longer Cone/taller unit to be installed, and it's performance apparently is enhanced with the mods mentioned.

Certainly no "Expert Here", just my take on the data available.

[Dennis Peacock]

OK...Since dust collection and cyclones seem to stir up a mess in threads, I'll post just once.

I have a Bill Pentz design Cyclone. I worked very closely with Terry Hatfield in testing and other things of various cyclone changes. We discovered that by using the air ramp caused a "severe" loss of CFM and a "strong" increase in static pressue...neither of which is good for best overall dust collection. The inlet on this cyclone is angled down slightly to allow the air/dust to begin its journey to the bottom of the cyclone. Needless to say, my cyclone only has the center cylinder that connects to the blower and center part of the cyclone upper body. Other than that? It's hollow inside and works perfectly.

'nuff said by me on this. :rolleyes: ;)

[Chris Padilla]

I sure would like to think I'm ambitious enough to test my cyclone in both ways but I have a feeling when I hook it up, and it works (and seems to work fine), that I will suddenly lose that ambition to take it all apart again and tear out the ramp and remeasure! :) We'll see...that is still in front of me. :)

It isn't that I doubt you, Dennis, but Bill must've had some reason to go to all that extra trouble to install the helical air ramp. As you know, it is a pain in the butt to make and install it. I had to bend 80 tabs on that sucker to get it ready to install!

What led you to even consider removing the air-ramp in the first place?

Ah, I can see my potential future post already and the blood that will be spilled and Ken S. will have to step in and clean house and lock the thread and, and, and..... ;) :D

[Jerry Olexa]

Good info guys and thank you but...You all seem to be talking about using them w cyclones. I'm considering it for a Single stage 2 HP unit. Am I off base or "clueless"?

[Norman Hitt]

Jerry, maybe my electrons aren't flowing today, but I just can't visualize how you would use an NGV in a single stage DC, or where you would put it in one of those, because with a system that has an upper and lower bag, it doesn.t seem to me that there is any body length suffecient to install an NGV. What kind of single stage setup do you have?

[Terry Hatfield]

What led you to even consider removing the air-ramp in the first place?

Ah, I can see my potential future post already and the blood that will be spilled and Ken S. will have to step in and clean house and lock the thread and, and, and..... ;) :D

OK Chris...let's see if I can jump in here without causing too much trouble...hopefully...

It was in reality a matter of not putting it in the DE cyclones like Dennis' rather than removing it. The cyclone works either way. There are plenty of examples of both out there. IMHO...and that is what this is...just my opinion backed up with my test numbers...the ramp did not do what it was intended to do in the DE cyclones.

When the DE project began Bill altered his original design. The inlet size was changed to 4" X 10" rather than his original configuration so a regular HVAC register boot could be used to attach the ductwork to the cyclone instead of having to form the complicated transition yourself. That change meant that the outlet in the cyclone went from 9" dia. to 10" in the DE to make everything fit up to the narrower neutral vane/inlet. Everyone that was working on the DE's came to the conclusion that that change apparently did not leave enough space inside the cyclone and the extra resistance of the ramp in the DE cancelled out any gains in smoothing the air flow. The best answer that we could come up with was that there were too many surfaces in too small of a space inside the cyclone. I built prototypes with and without the ramp and tested with the same blower. The cyclone without the ramp had about 1" of resistance across the cyclone. The one with the ramp had 4" of resistance. Approx. 200 cfm was lost to this extra resistance. I still use the original rampless cyclone protype today. You saw it perform, Chris. It does OK. :) Seperation is great and I certainly have no complaints about the overall performace of the machine. After fighting with a stack of ramps in various sizes trying to get the thing worked out, it did not hurt my feelings to just leave it out. It was by far the most complicated aspect of the construction. I think the DE cyclones at least are better off without it but then again what do I know?? I'm just some redneck hacker from Arkansas.

I have ZERO experience with anything except the old DE's so perhaps the 9" outlet design has enough room for the ramp to function as it was intended. I really don't know. It would have to be tested in both configurations to know for sure. As far as I know it has not been tested with and without the ramp but perhaps it has. Bottom line is that the cyclone will function either way and I certainly wouldn't be ripping any ramps out just to see.

t

[Terry Hatfield]

Good info guys and thank you but...You all seem to be talking about using them w cyclones. I'm considering it for a Single stage 2 HP unit. Am I off base or "clueless"?


Jerry,

You are neither...I think. I know I have corresponded with a couple of guys that were playing around with the neutral vane in the bag ring of a regular bag type DC with canister filter conversions. I have searched high and low for those mails but I can't seem to find them. Personally, I believe that there would not be much if any performance gain. These guy's were trying to direct the chips/dust more into the collection bag rather than into the cartridge filter that they had on their DCs. I can see benefit in doing that for sure. The cartidge filter downfall is clogging because there is no cyclone to seperate the chips before they get to the cartridge. I'll keep seraching. I know I have them saved...I save every mail. That is my problem. There is only about 5000 of them to pick through. :)

t

[Dale Thompson]

Hi folks,
As you already know, I make enemies at an alarming rate. At my age, however, I don't really care. :confused: If you REALLY want to collect "dust", get a bag collector with the fabric sized to the micron size of your dust. Clean the bags, as required, with a blast of 90 psi air.

I know that "cyclones" are highly touted in the ww world. The fact is that they are very inefficient at removing serious "dust". The concept of a cyclone is that the rapid spinning of air will separate the "big" stuff from the "small" stuff due to cetrifugal force(centripetal force for you physicists). The taller the "cyclone" and the more HP spinning the air will help. However, "neutral" vanes theoretically defeat the purpose of the "cyclone". They inhibit or reduce the "spin" with which "cyclones" accomplish their intended purpose. Our ww "cyclones" use a secondary filter which, hopefully, get rid of the "fines" which sneak through the physics of the "cyclone". That is a GOOD thing.

I guess that my point is: Let the cyclone do ITS job and depend on the after-filter to do ITS job. Don't take the "Mask off the old Lone Ranger" and don't mess around with the physics of your system! :eek: :eek:

Cheesch!! Here come the guys in the white coats!! AGAIN!! ;) HELP!! :cool:

Dale T.

[mike lucas]

Bill Pentz seems to be the cyclone guru to talk to about all of this stuff. He now sells assembled cyclones, and from what I read. I believe that he uses the neutral vane in them. I was under the impression that the reason for the NV was that the perfect ratio for a cyclone is 3 to 1 (IE: 3 feet tall for every 1 foot in diameter.) Bill designed his cyclones at a 1.64 to 1 because of the fact that most hobby workshops do not have wall tall enough to accomadate the perfect size you would need. So the NV is used! If Bill has put in half as much work in designing the cyclone as he has in developing his web site. I believe he is as much of an expert as anyone.

[Chris Padilla]

I have ZERO experience with anything except the old DE's so perhaps the 9" outlet design has enough room for the ramp to function as it was intended. I really don't know. It would have to be tested in both configurations to know for sure. As far as I know it has not been tested with and without the ramp but perhaps it has. Bottom line is that the cyclone will function either way and I certainly wouldn't be ripping any ramps out just to see.

t
Thanks, Terry, for your thoughts. I was hoping you'd chime in with your wisdom.

If you could use some of my pictures from the thread above, could you explain to me what the 10" or 9" dimension is that you are referring to? I don't quite follow and I don't know what mine is. Are you referring the radius of the cylinder body of the cyclone?

You said you tested (for the DE) both with and without the ramps. If you still have that test equipment and it isn't too much trouble, I would like to have it and I'll run my BP/CE cyclone both with and without the ramp. I'll go through the fuss and do it.

Since I already have it installed, I'll go with you and assume it'll be better without the ramp but it won't be too bad to reinstall it. Most of the hard work for the ramp was just bending 80 tabs and getting it bolted into the cyclone body...that work is all done whether I put it back in or not.

Thanks! :)

[Jim Becker]

I'll keep seraching. I know I have them saved...I save every mail. That is my problem. There is only about 5000 of them to pick through.
Terry, if you use Outlook (not Outlook Express), Lookout for Outlook (http://www.lookoutsoft.com/Lookout/) will greatly speed your searching since it indexes your email.

[Terry Hatfield]

Terry, if you use Outlook (not Outlook Express), Lookout for Outlook (http://www.lookoutsoft.com/Lookout/) will greatly speed your searching since it indexes your email.
\\j,

I use outlook for my business but I'm so used to AOL for my personal stuff I'll probably stay put. I gotta catalog these mails one of these days so I can find stuff better.....one of theses days.....

Thanks,
t

[Terry Hatfield]

Chris,

The cyclone outlet, the round cylinder leading to the blower inside the cyclone body, was 9" diameter in the original Pentz design and I believe it is that way in the Echols also. The change in the intake size on the DE required the outlet to be changed to 10" diameter. The intake/neutral vane needs to occupy the entire space between the outlet and the cyclone body. 4" in the DE, 4 1/2" in the original. I'm not sure if that change caused the extra resistance or not but I do know that the extra resistance of the ramp cancelled out any performance gains that it was supposed to have made by smoothing the air flow. Keep in mind here that I have tested nothing but the DE design so perhaps the same is not true in the other designs. If you have the thing installed I still say I would not pull it out just to test.

Sorry, but I can't help you with the testing equipment. I borrowed the equipment from an EE friend of mine and returned it to him long ago.

t

[Chris Padilla]

Thanks, Terry. :) Odds are good I won't pull it out...I know laziness will overcome everything! :D

[Jerry Olexa]

Thanks guys for all your info and postings. Chasing neutral vane info is not easy. It is mentioned briefly on B. Penz's site. BradOlson, a member here, has posted several in-depth threads on their effectiveness on other WW sites and below LCHIEN shows you how to actually make one. I'm gathering you have to make them vs buying (I'm no metalsmith!) and opinions are slpit on their effectiveness. Some people strongly swear by them and others do not. So i guess I'm still a little confused. We'll figure it out I suppose prior to me buying metal and snips.
Thanks..:confused: As always, your advice is invaluable!
http://bt3central.com/forum/topic.asp?ARCHIVE=true&TOPIC_ID=7960&SearchTerms=,I,completed,,

[Jerry Olexa]

PS. I voted FOR the neutral vane BEFORE I voted AGAINST it. I remain neutral,Vain as I am (vane). No political reference here!!

[Brad Olson]

I should emphasize Terry's point about the NV in the HF 2HP DC. The only point of the NV is to keep in the air from going around the circle and crashing into incoming air causing the chips to fly upward into the canister. Since bag ring DC's arent' very good to begin with, the NV, helps direct the airflow downward, giving the major debris a chance to fall out. Canister conversions of bag rings still do keep the fine dust suspended and throw it into the filter. Thus you do have to clean the filter of bag ring style more than a cyclone, there just isn't a way around it.

When I designed my (ugly) NV, the only variable I was testing was wheter or not visible dust and debris were being propeled upward into a topless bag ring tomake sure that the fully assembled DC didn't have issues with too much debris flying up into the cartridge.

Hope that helps, and you can link to all my pages from my WWW link. Most of the major discusssion of this happened over on bt3central because Scott Scherrin was the first to convert a HF 2 HP DC to a canister with a Wynn filter and several other members used a Griz canister filter. I was number 2 for the Wynn conversion and did a lot of work with Wynn environmental on increasing duct size (to 6" becase the canister allows a huge increase in airflow, at least 4 fold increase in airflow and then allowing 6" ducts to a single machine at a time) and adding the NV to prevent premature filter clogging (the previous biggest complaint about converting a bag ring DC to a canister)


I did mention to Terry Hatfield that I am messing around with an air ramp style of NV, to see if this helps control turbulence. My initial design suffered from a high increase in pressure (just like Terry mentioned as being a problem with the cylcone). Since I am doing some projects right now, I haven't really had any more time to mess with things, so my NV is litterally a piece of rounded off gutter tin duct taped into my DC. Yeah its ugly, but it works.

Hope all of this is of some use, an PM or post if there are further questions, I am somewhat new to SMC, but enjoying the lack of trolling here so far (spend time on Woodnet to see what I mean)!

[Jerry Olexa]

Brad , thanks for your response. I'm very impressed w the research,and work you did on the HFDC cartridge conversion and NV. I'll be using you for guidance as I plunge into my project. Thanks for your efforts. I also agree this is a more "friendly" place as opposed to some of the others out there.

[Tom LaRussa]

In my studying for a new Dust Control system, I've encountered "nuetral vanes". In both cases, the owner built one themselves and claimed increased performance significantly. What your opinion on these? necessary or desirable? Can you buy them rather than build? And what is their general function? Thanks in advance..As always, I value your input more than the mags, etc Jerry
Jerry,

I added a really basic ramp-type thingie to my Delta 1.5 HP DC unit and it seems to have helped keep the dust down in the lower bag instead of pumping it up into the canister filter. But I've never tested it scientifically, so I can't be sure.

Anyway, here's a link to a thread I started on the subject. I have pictures of what I did.

http://www.sawmillcreek.org/showthread.php?t=12507

[Brad Olson]

Brad , thanks for your response. I'm very impressed w the research,and work you did on the HFDC cartridge conversion and NV. I'll be using you for guidance as I plunge into my project. Thanks for your efforts. I also agree this is a more "friendly" place as opposed to some of the others out there.
No problem on helping others, I have learned tons from the various message boards and am trying to give something back to the community. I glad others are using my experiences to improve the dust collectors a bit. I am also pretty pleased with the results I got with the conversion as well as the CS from Wynn environmental. Best part was, I was able to put in a pretty darn good DC system including piping for just a couple of bucks under $300. Since it is a canister system and really filters down to 1 micron, I am even more pleased since the though of spending $500-900 on a DC made my heart skip a few beats (especially since I am a poor graduate student!).