LumberJocks

All Replies on Cyclone confusion

  • Advertise with us
View k4zmb's profile

Cyclone confusion

by k4zmb
posted 08-17-2019 01:31 AM


43 replies so far

View MJCD's profile

MJCD

598 posts in 2877 days


#1 posted 08-17-2019 02:18 AM

I can’t directly answer your question… However, I do have a few questions…

A 4” for your main run is far too small (a statement, not a question). A 6” will provide 36/16 = 2.25x the air flow capacity, and can be supported by a 2hp motor… Delta sold a 1.5hp version, with a 6” inlet, for years, and is probably still doing this – I had one for many years.

My recommendation is to get the specs on both Oneida and Clearvue systems, and reverse engineer what you need. That is, both Oneida and Clearvue sell commercial-grade, well-engineered systems (and they charge you for it). Their specs on cyclone inlet diameter, cyclone length and CFM should be available on their websites or on downloadable documentation – though, Clearvue had horrible documentation, the last time I checked. Delta, Grizzly, and the others in this category may provide specs on their equipment, as well.

For example, the Clearvue system has two impeller options – 15” and 16” (last time I looked), so the housing must be approximately 18” in diameter. The cone is probably 3’ long, and tapers to approximately 6”-8”: that is, approximately 18” tapering to 8” over a 3’ length – again, this information should be ascertainable from close review of their website/documentation information.

A final recommendation is a 6” main run, with 4” drops to the machines; or if possible, replace the machine connections with 6” orifices; otherwise, the 4” runs will choke the CFM throughput.

View therealSteveN's profile

therealSteveN

3865 posts in 1080 days


#2 posted 08-17-2019 02:22 AM

Not an eggspurt on cyclones, but I have seen a bunch of them, and seen even more comparisons about many of the ones available. They come in a variety of shapes, sizes, inlet sizes, and outlet sizes. I don’t have a quibble with you trying to make one up, but I would make it look perzactly like the appropriate sized Onieda Dust Deputy. They generally kick butt in comparison testings. Also of all the cyclones, and make it at home designs, I don’t hear about people having to empty them, before being filled, because they almost lost all suction.

On the HF’s I see most often people saying to knock off the 4” splitter cap, and keep it 5” till you get really close to the machine. As above 6” is also a possibility, but would require some work on the HF motor, it comes out as 5”

-- Think safe, be safe

View MJCD's profile

MJCD

598 posts in 2877 days


#3 posted 08-17-2019 02:37 AM

The Super Dust Deputy is an excellent solution. I had one for many years, and it is still in-use – I added a mobile base, and sold it to upgrade to my large Clearvue.

View k4zmb's profile

k4zmb

19 posts in 140 days


#4 posted 08-17-2019 11:21 AM

Thanks to all of you for your feedback, input and advice. I have contacted Oneida and received specs and dimensions of their 4” Dust Deputy, ( they recommended the 4” for my HF DC). I have scrapped my original plan based on Pentz’s figures and will have local machine shop cut and roll a piece of 22 g sheet metal that I have to Oneidas specs. I’ll rivet then seal the 1” seam. The top will be 3/4” plywood with 4” outlet to DC, (Oneidas’ recommendation), with a very short, less than 18” to DC inlet. As HF uses 4” hose for collection, I’ll keep 4” cone inlet. Considering using 5” or 6” hose to DC. Or should I convert 4” to 6” to cyclone inlet?
I spent two + hours sealing all openings on my older Rockwell TS, which greatly improved dust pick up. I’ll upgrade when finances allow to a larger impeller and a Wynn filter. I’ll post pics when I have something worth showing. Thanks again to all.

-- Marc, “When in doubt, err on the side of caution”

View k4zmb's profile

k4zmb

19 posts in 140 days


#5 posted 08-17-2019 11:34 AM



I can t directly answer your question… However, I do have a few questions…

A 4” for your main run is far too small (a statement, not a question). A 6” will provide 36/16 = 2.25x the air flow capacity, and can be supported by a 2hp motor… Delta sold a 1.5hp version, with a 6” inlet, for years, and is probably still doing this – I had one for many years.

My recommendation is to get the specs on both Oneida and Clearvue systems, and reverse engineer what you need. That is, both Oneida and Clearvue sell commercial-grade, well-engineered systems (and they charge you for it). Their specs on cyclone inlet diameter, cyclone length and CFM should be available on their websites or on downloadable documentation – though, Clearvue had horrible documentation, the last time I checked. Delta, Grizzly, and the others in this category may provide specs on their equipment, as well.

For example, the Clearvue system has two impeller options – 15” and 16” (last time I looked), so the housing must be approximately 18” in diameter. The cone is probably 3 long, and tapers to approximately 6”-8”: that is, approximately 18” tapering to 8” over a 3 length – again, this information should be ascertainable from close review of their website/documentation information.

A final recommendation is a 6” main run, with 4” drops to the machines; or if possible, replace the machine connections with 6” orifices; otherwise, the 4” runs will choke the CFM throughput.

- MJCD


Steve, i did get specs from Oneida. I told them that I had 2 hp DC with 4” inlet & they recommended the 4” cyclone.should I remove the 4”Y and use a 5” to 6” reducer, if I can find one, into the impeller housing? Would that improve CFM, but reduce air speed? I take your advice that Oneida has got this figured out, because my small Dust Deputy does a great job with just the shop vac.
I’m just trying to figure out the connections between DD & DC. I plan to keep that connection short & on a mobile stand to get close to each machine to improve collection and decrease air flow resistance. Given that do you suggest using 6” pvc or duct to machine & then reducer to 4” machine port?
Thanks, Marc

-- Marc, “When in doubt, err on the side of caution”

View ibewjon's profile

ibewjon

989 posts in 3299 days


#6 posted 08-17-2019 02:23 PM

With a 1 1/2 HP, I think the 6” duct is oversized. Wood magazine articles have recommended 5” steel duct, with 4” being too small, except for drops. That is how I built my system, and no complaints. I am going to purchase an industrial style air speed / CFM meter soon just to get some real numbers for my system.

View k4zmb's profile

k4zmb

19 posts in 140 days


#7 posted 08-17-2019 02:43 PM

With a 1 1/2 HP, I think the 6” duct is oversized. Wood magazine articles have recommended 5” steel duct, with 4” being too small, except for drops. That is how I built my system, and no complaints. I am going to purchase an industrial style air speed / CFM meter soon just to get some real numbers for my system.

My DC is a 2 hp, does that give me much advantage over the 1 1/2?
I could not find any 5” metal duct in local big box stores, so that presents a challenge. I suppose I could make my own from 6” by cutting, riveting & soldering.
BTW, I purchased a Proster anemometer that does have CFM mode. It seems to work well.
Thanks for the offer input.
Apparently there is some margin on specs as there are a lot of people using various sizes of cyclones, duct sizes, etc. Do you have an opinion on the Jet 12” impeller to replace the stock HF one?

-- Marc, “When in doubt, err on the side of caution”

View ibewjon's profile

ibewjon

989 posts in 3299 days


#8 posted 08-17-2019 04:04 PM

I believe both Menards and Home Depot and probably Lowe’s can get the 5”, 26 guage, just not a shelf item. And others have found it to be cheaper than PVC. I bought mine from a heating supply company. I do not have a cyclone, no real estate to park it in. My collector is a 2 HP from north state machinery about 25 years ago. It draws 9.4 amps on 250 volts. I replaced the bags with the Jet pleated filter and added a vortex cone. Check your amps while running if you can. Motor tags from overseas are inaccurate these days. Mine is a stock impeller, unknown diameter. I have read that an anemeter does not really work for this, so I will be ordering from Dwyer. About $150. I have connected their instruments many times, and they are a long established company. Look up dust collector ductwork on Wood magazine.

View Fred Hargis's profile

Fred Hargis

5738 posts in 2999 days


#9 posted 08-17-2019 05:51 PM


My DC is a 2 hp, does that give me much advantage over the 1 1/2?

- k4zmb

You said earlier it was the HF DC you have. That is almost certainly not a true 2 HP, more likely 1.5. It’s a good bet that a 12” impeller would overload that motor (besides, it may not fit in the blower housing) but there was a thread here some time back where someone used an 11” (I think) Rikon impeller and seemed to be relatively satisfied with it. I searched a little and couldn’t find the thread, but maybe whoever it was will see this and chime in.

-- Our village hasn't lost it's idiot, he was elected to congress.

View k4zmb's profile

k4zmb

19 posts in 140 days


#10 posted 08-17-2019 08:11 PM

Thanks. I might have seen the impeller upgrade on YT, and it could have been an 11 inch impeller. Is there an accurate way to measure hp other than extrapolating from the amp reading with a meter?

-- Marc, “When in doubt, err on the side of caution”

View Fred Hargis's profile

Fred Hargis

5738 posts in 2999 days


#11 posted 08-17-2019 09:07 PM

None (that I’m aware of) that we mere mortals would be able to do.

-- Our village hasn't lost it's idiot, he was elected to congress.

View ibewjon's profile

ibewjon

989 posts in 3299 days


#12 posted 08-17-2019 09:22 PM

Amps. X. Volts. =. Watts. Watts ÷ 746 equal approximate HP. That is the mortal way.

View Todd_R's profile

Todd_R

19 posts in 253 days


#13 posted 08-17-2019 11:09 PM

http://www.clearvuecyclones.com/forum/forum/clearvue-cyclones/product-questions/477-what-size-cyclone
Note in his sizing comments a 1.64 ratio for the cone (with a 18” diameter).

However, contacting Oneida to get specs isn’t a bad way to go. Their systems definately work as I can attests since I have a couple of their cyclones now.

That said with your design (using the 4” port with a HF 2 HP motor) I would keep the run very short and direct to your system so as to obtain the performance necessary. If you don’t you could end up with a lot of dust sitting in the ducting and a potential fire risk.

-- Todd

View HackFabrication's profile

HackFabrication

159 posts in 217 days


#14 posted 08-18-2019 12:38 PM


It s a good bet that a 12” impeller would overload that motor (besides, it may not fit in the blower housing) but there was a thread here some time back where someone used an 11” (I think) Rikon impeller and seemed to be relatively satisfied with it. I searched a little and couldn t find the thread, but maybe whoever it was will see this and chime in.

- Fred Hargis

My on-going HFDC build (many have done this using the Rikon 11 7/8” impeller: Dust Collector

-- "In the end, it's all Hack..."

View EarlS's profile

EarlS

3085 posts in 2854 days


#15 posted 08-18-2019 03:05 PM

For what you will likely spend having the sheet metal rolled, your time, etc. IMO you would be money, time, and confusion ahead to simply by the metal version of the Oneida 5” or 6” Super dust Deputy.

As for sizing, a 6” main will allow you to use all of the cfm the blower provides and minimize pressure loss in the duct work. Reduce to 5” on your drops to the equipment and then reduce to the dust port size on the equipment (4” usually).

I just bought a Delta 50-850 (1.5 HP, 1200 cfm, 11” WC) that I intend to retrofit with a filter cartridge, 6” SDD, and 6” mains. I also found a YouTube video where the guy also took a bunch of cfm readings along the way. Being an engineer, I’m going to get an anemometer and maybe a manometer and do the same thing he did and document the performance.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

View k4zmb's profile

k4zmb

19 posts in 140 days


#16 posted 08-18-2019 04:46 PM

Thanks for the info Earl.
My replies following yours:
For what you will likely spend having the sheet metal rolled, your time, etc. IMO you would be money, time, and confusion ahead to simply by the metal version of the Oneida 5” or 6” Super dust Deputy. A local sheet metal shop sold me a 48” x 48” piece of galv sheet metal & will cut & roll it for $40.00. I couldn’t pass that up.
As for sizing, a 6” main will allow you to use all of the cfm the blower provides and minimize pressure loss in the duct work. Reduce to 5” on your drops to the equipment and then reduce to the dust port size on the equipment (4” usually).
I’m planned no on making a rolling cart/tower to be able to move the DC close to each machine to minimize resistance in long runs. (A pain, but if it improves collection I’ll deal with it).Using sheet metal ducts should prevent static caused explosions or fires. Any pvc that I’ll use will have copper wire inside and wrapped around. I know that this may be overkill, but better to err on the side of caution.
I just bought a Delta 50-850 (1.5 HP, 1200 cfm, 11” WC) that I intend to retrofit with a filter cartridge, 6” SDD, and 6” mains. I also found a YouTube video where the guy also took a bunch of cfm readings along the way. Being an engineer, I’m going to get an anemometer and maybe a manometer and do the same thing he did and document the performance.
Some posts have said anemometers may not be accurate, but like any measuring device it is a reference when using to compare. But, I could be wrong.

-- Marc, “When in doubt, err on the side of caution”

View AndyJ1s's profile

AndyJ1s

62 posts in 261 days


#17 posted 08-18-2019 10:57 PM



Amps. X. Volts. =. Watts. Watts ÷ 746 equal approximate HP. That is the mortal way.

- ibewjon

That’s input power, or would assume 100% motor efficiency for output power.

Lacking documentation, assume ~80% (or less) efficiency for single phase electric induction motors.

Input power X efficiency = output power.

Andy

View ibewjon's profile

ibewjon

989 posts in 3299 days


#18 posted 08-18-2019 11:25 PM

Wire inside the duct? Buliding clogs. And how is wrapping wire around the outside of a plastic duct going to do anything? Sounds like building a capacitor to add to the static charge. Steel all the way for me. And yes, 746 Watts assumes a perfect world, no friction, or other loss. And I believe that 6” is too big for a 1 1/2 HP. I would use 5” which is what I have on my 2 HP, and it works great.

View k4zmb's profile

k4zmb

19 posts in 140 days


#19 posted 08-19-2019 12:52 AM

Thanks Ibewjon, it’s good to know that the 5” is working well for you because the more I read and hear the more confusing it gets. Oneida recommended their 4” model, but it seems like that would lower the CFMs. I think that I will compromise and use a 5” inlet/outlet on the cyclone & 5” metal duct. I’ll only use very short pieces of pvc if I can’t get metal duct to fit. A short length of wire in pvc will drain the static charge won’t it? I do understand, though how it could trap debris. Wire on the outside should be able to dissipate static charge as well I’ve been told, but ??? There’s do much conflicting advice about that, that I want to use as much of the metal duct as I can.

-- Marc, “When in doubt, err on the side of caution”

View therealSteveN's profile

therealSteveN

3865 posts in 1080 days


#20 posted 08-19-2019 01:54 AM

The guy on that famous auction site who goes by eastcaroga, spins up a 6” model. Much larger flow than Oniedas, and less $$$$ for metal. I was impressed by the build he sent me. It’s allowing me to stay 6” on my DC trunk, and empties everything inline from my TS, 8” Jointer, and 15” Planer.

I didn’t know what to expect, but it took my Grizz 2Hp to a new level. I’m setting it up now for permanent use. When the HEAT allows.

-- Think safe, be safe

View k4zmb's profile

k4zmb

19 posts in 140 days


#21 posted 08-19-2019 10:22 AM

Thanks Therealsteve. I’ll try to find him. Would that auction site be EBay?

-- Marc, “When in doubt, err on the side of caution”

View k4zmb's profile

k4zmb

19 posts in 140 days


#22 posted 08-19-2019 10:56 AM

Just watched a YT video by saVRee on cyclone separators. Very helpful as he describes the relationship between particle size, cone diameter, inlet and outlet size and cone geometry.

-- Marc, “When in doubt, err on the side of caution”

View ibewjon's profile

ibewjon

989 posts in 3299 days


#23 posted 08-19-2019 02:26 PM

As for grounding PVC, PVC is an insulator, a NON conductor. The static builds on the surface, and does not transfer to the wire. A tip in the same wood magazine issue as the duct size suggested wrapping aluminum tape around the pvc. In fact, it won the writer a $300 gift. Being an electrician, I decided to test the idea on my steel duct. I took ohm readings from the tape I used to seal the joints to the actual steel. It had a very high ohm reading, which I don’t remember. Definitely not a connection to drain any static on pvc. And after reading an article listed in that issue of wood, that the award committee did not read, it confirmed what I already knew, that wrapping a conductor around the pvc creates a capacitor, which stores the static and creates a larger shock. The vortex cone I added works like a cyclone, separated chips, and doesn’t use any floor space in my small shop.

View k4zmb's profile

k4zmb

19 posts in 140 days


#24 posted 08-19-2019 03:39 PM

Thanks again IbeWJon for the clarification. So what your saying is that in a run of pvc any static created by the moving dust particles would not be potentially explosive because the pvc acts Luke an insulator? Or did I misunderstand? So what causes explosions in grain silos?

-- Marc, “When in doubt, err on the side of caution”

View ibewjon's profile

ibewjon

989 posts in 3299 days


#25 posted 08-19-2019 05:07 PM

No, I did not mention explosive. I said the PVC is a layer of insulation between the two conductors, the dust stream and the foil tape or copper wire. This layering acts like a capacitor to store the charge and could create a larger shock. The article noted in wood magazine stated there is a very small chance of explosion in a home shop. It is the March 2017 issue of wood that has the duct size and material article. There is also an article about PVC grounding at woodmagazine.com/PVCgrounding. Be sure to go online and read the article footnoted in the PVC grounding article. By definition from the National Electrical Code, an electrical system is GROUNDED once, the downstream connections are BONDING connections. So we are really bonding different parts of the system together to eliminate a difference in potential ( static buildup) between parts. I wish the foil tape would work, but it didn’t even connect to the steel duct. I believe it is the layer of glue on the tape being an insulator. The small surface of wire on PVC is also not a good connection. Using wire jumpers across the PVC will bond the steel together eliminating a difference in potential between separated pieces of duct. I also bond both ends of the steel spiral in flex duct to the steel duct. Probably tooooo long of reply, but look at those articles and draw your own conclusions.

View Fred Hargis's profile

Fred Hargis

5738 posts in 2999 days


#26 posted 08-19-2019 06:58 PM

Grain elevator (and other dust explosions) require an incredibly high concentration of dust…if this was the case in your shop you wouldn’t be able to breathe. The only reason to ground a home DC system (IMHO) would be to mitigate the discomfort of personal static shock. Otherwise it just complicates life down the road. Be aware, you will make changes to your DC system (if it has fixed ductwork) and things like grounding wires just makes things a PITA…along with being ineffective.

-- Our village hasn't lost it's idiot, he was elected to congress.

View k4zmb's profile

k4zmb

19 posts in 140 days


#27 posted 08-19-2019 07:13 PM

Thanks for the clarification. Apparently then, there is a lot of misinformation on YT. Not a surprise.
On another aspect, some have built cyclones with a cylinder on top of the cyclone, but do you think that that is essential or can the cyclonic spiraling be accomplished with just the cone?
I’m thinking that my build will be a top diameter of 20”, 5” inlet & outlet & 18-20” length, ( vertical), height. So hard to know what might give the best results. Pentz’s info was above my understanding. I would buy an Oneida if my local sheet metal & duct manufacturer hadn’t offered to do it for $80.00 sheet metal included.
They will roll it and form it & I’ll rivet & seal it. I’ll use 3:4” plywood for the top @ 5” metal duct for top & side ports.

-- Marc, “When in doubt, err on the side of caution”

View k4zmb's profile

k4zmb

19 posts in 140 days


#28 posted 08-19-2019 07:17 PM

On the grounding, yes it is a PITA every time I move the HF DC. I’ll 86 that idea because you are right. I don’t have that much fine dust and running wire would be unnecessary.
Thanks again for helping me wade and brought all this #%*

-- Marc, “When in doubt, err on the side of caution”

View gwilki's profile

gwilki

322 posts in 1979 days


#29 posted 08-19-2019 08:55 PM

k4zmb: You mentioned that you sealed up your table saw. Just remember that your dust collector can only move as much as is coming in. If you seal your saw too tightly, you will get no dust collection. Make sure that you have air coming into the saw so that the direction of the air leads to your extraction hose/pipe.

-- Grant Wilkinson, Ottawa ON

View ibewjon's profile

ibewjon

989 posts in 3299 days


#30 posted 08-19-2019 08:56 PM

Metal duct solves all problems. Just a wire along the flex. Sorry Fred, I bond everything in my dust collection system. I am not getting any unnecessary shocks. And it is not a pita, bonding is easy. Shocks are.

View Fred Hargis's profile

Fred Hargis

5738 posts in 2999 days


#31 posted 08-19-2019 09:49 PM

I built my first cyclone from the Wood magazine plans, and it had the body on top of the cone. I see that as necessary for good design since it also allows for a neutral vane and that center pipe to collect the air. But some of the new bastardized designs (my word for them) shorten or almost eliminated the body section, and they are virtually all cone. Just my opinion…..

-- Our village hasn't lost it's idiot, he was elected to congress.

View therealSteveN's profile

therealSteveN

3865 posts in 1080 days


#32 posted 08-19-2019 10:16 PM



Thanks Therealsteve. I’ll try to find him. Would that auction site be EBay?

- k4zmb

Yes it is. I read somewhere not to post places to buy, though we frequently post places that carry stuff. I admit to confusion…...

-- Think safe, be safe

View Ocelot's profile

Ocelot

2352 posts in 3144 days


#33 posted 08-19-2019 10:19 PM

Long ago (25+ years) when FCC started caring about electromagnetic interference (EMI) the company I worked for had just committed to building housings for the computer workstations we made out of “structural foam” plastic (Remember the Apple II – same stuff). These workstations contained CRT’s, so they were pretty big. The molds for these large pieces were very expensive – on the order of $500K, so when the new FCC requirements came in, we tried to mitigate EMI by making the plastic conductive on the inner layer. First, we used special conductive paint. That got us by for maybe a year, but we weren’t passing the FCC testing, so then we were stapling copper mesh to the inside the plastic cabinetry and had copper “fingers” where the covers came together to complete the shielding.. In the end, we had to go back to sheet metal, because all of that copper mesh and the labor to make it that way were just too expensive.

View k4zmb's profile

k4zmb

19 posts in 140 days


#34 posted 08-19-2019 10:47 PM

k4zmb: You mentioned that you sealed up your table saw. Just remember that your dust collector can only move as much as is coming in. If you seal your saw too tightly, you will get no dust collection. Make sure that you have air coming into the saw so that the direction of the air leads to your extraction hose/pipe.

—Grant Wilkinson, Ottawa ON
Thanks Grant. Would the opening in the TS insert for the blade not be enough? Or should I remove some of the pipe insulation that I used to seal up any leaks?
Im still learning about dust collection and appreciate all of the help and advice.

-- Marc, “When in doubt, err on the side of caution”

View k4zmb's profile

k4zmb

19 posts in 140 days


#35 posted 08-19-2019 10:49 PM

P.S. Since my TS has the motor hanging of of the back of the saw, (it’s an older 2hp Rockwell), would there be enough air intake coming in around motor mounts and around the drive belt?

-- Marc, “When in doubt, err on the side of caution”

View therealSteveN's profile

therealSteveN

3865 posts in 1080 days


#36 posted 08-19-2019 11:32 PM



Grain elevator (and other dust explosions) require an incredibly high concentration of dust..

- Fred Hargis

Any grain silo has a HUGE amount of dust full time. What it requires is the precise mix of air, and fuel (the dust) and some form of ignition.

I had an unheated pole building at the last place, and I used one of those huge salamander heaters. No danger of CO2 poisoning because of all the drafts in the barn. I had been sawing at the TS for over an hour, piece after piece, so also not having any form of dust collection beside my trusty leaf blower I had a cloud of fines in the air around me. At which time the burner on the heater decided it had gotten too cool in the building, and popped to life. Evidently this resulted in the exact perfect mix of air, fuel, and an ignition source, and Whoosh. The entire space was a fireball, but just for a split second. That fire triangle requires all 3 of it’s needed parts, and with the whoosh, it consumed all of the available airborne dust, and extinguished itself. It’s a good thing, because I about crapped my pants, which may have been considered available fuel. Didn’t even fog my respirator, much less singe an eyebrow.

Pretty much that is what the silo needs to happen. Except maybe the idgit with the salamander.

-- Think safe, be safe

View k4zmb's profile

k4zmb

19 posts in 140 days


#37 posted 08-20-2019 12:43 AM

OMG! I would have too, and probably worse.

-- Marc, “When in doubt, err on the side of caution”

View ibewjon's profile

ibewjon

989 posts in 3299 days


#38 posted 08-20-2019 01:20 AM

The last silo/ elevator explosion near me killed three and left a pile of concrete. That is why the electrical code has a special section for dust. And even though the chance at home is small, I use steel duct and bond / ground it to death.

View farmfromkansas's profile

farmfromkansas

125 posts in 120 days


#39 posted 08-20-2019 09:09 PM

My local coop grain elevator has a cyclone DC on their leg that elevates the grain up into the bin, to separate the dust from the air in the bin. Eliminates the problem of dust explosion. And all the ductwork on the elevator is steel. Note that the DC they use is larger than what we use in wood shops. Even larger than Clearvue.

View fivecodys's profile

fivecodys

1484 posts in 2142 days


#40 posted 08-20-2019 09:30 PM

When designing my small DC System I read all I could and then contacted Oneida for their assistance.
They recommended 5” duct based on the SDD I purchased and the blower I was going to use.
When you are designing a small system based on a small blower every little bit of efficiency gained can really add up.
One of the most important issues is to have at least 5 feet of straight duct before it enters the SDD. This allows some of the turbulence air flow to stabilize before it enters the cyclone. I also came across a fella here that added a vane inside the cyclone to help spin the air all in the same direction as it enters the cyclone.
When air spinning one direction meets air spinning the opposite direction the resulting collision can lower the efficiency by as much as 8% (per his calculations).

Running long sweeping elbows and as little hose as possible also helps your unit work more efficiently.
The less drag in the system the better.

It is amazing how well all this works together. I do not run the exhaust through a filter. It goes outside through a dryer vent into the flowerbeds.
I have yet to see any evidence of dust on any of the bushes which tells me that my SDD is working very efficiently.

Keep in mind this is a pretty small system but through lots of reading and advice from the fine folks here, it is working very well.

Here is the build thread. https://www.lumberjocks.com/projects/388617

I really enjoyed designing and building my DC system. I hope you enjoy it as well.

-- When you leave your shop for the night, make sure you can always count to 10.

View k4zmb's profile

k4zmb

19 posts in 140 days


#41 posted 08-21-2019 12:18 AM

Yes Fivecodys, there is great advice from those who no so much more than me. I’m still trying to work out the geometry, though. There is a fellow that did a YT video that was very good in exposing the parts, function, physics and geometry of cyclones. Pentz recommended 20-22 “ top diameter, but this fellow was saying that if it is too wide the particles can be drawn up and out of the cyclone rather than swirling downward, so too wide doesn’t allow them to hit the side of the cyclone and begin the cyclonic action downward. The trick is to have enough width at the top to allow needed air flow without sacrificing velocity, but not so wide that they don’t fall or so narrow that it restricts flow, but increases velocity.
I can see why so many have chosen to purchase a DD, rather than build one. The two companies have really put a lot of time, trial and study into the designs. However, being on a limited income, (retired), $200.00 + is out of my budget. I couldn’t pass up building one for less than $100.00.
Anyway, feedback and advice is very much appreciated.
Although I have done woodworking and carpentry most of my adult life. DC is not my area of expertise, still learning…

-- Marc, “When in doubt, err on the side of caution”

View gwilki's profile

gwilki

322 posts in 1979 days


#42 posted 08-21-2019 11:32 AM

k4zmb: You will likely be fine. You will know when you get things hooked up if you are getting good dust removal and if you are not, you can look to see if you need more air coming into the saw. I put a big gulp under my Rigid contractor saw and ran a 4” flex from it to a dust collector – no cyclone. It works reasonably well. I tried blocking the opening around the belt and motor, but ended up going to far and reducing the dust extraction. Just experiment; you’ll find what works best for you. I find the biggest dust issue with table saws is above the table/blade guard extraction. It’s tougher to find a good solution in a situation like mine, where I need to move the saw to use it.

-- Grant Wilkinson, Ottawa ON

View k4zmb's profile

k4zmb

19 posts in 140 days


#43 posted 08-21-2019 01:34 PM

There are some good tips on Pint*^%#t for TS top dust chutes, etc.
Thanks again for encouraging words. I’ll do the T&E til I get it right.

-- Marc, “When in doubt, err on the side of caution”

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com