Another dc ?

[erin patton]

Hello all,

1st post and wanted to let everybody how awesome smc is!!! I have been reading as many threads as I can on dust collectors the last few days. There is so much info I'm overloaded.

I recently bought a used 36" widebelt sander and it came with a dust collector. The collector has a 7.5 3 phase motor, 15" impeller with 9" inlet, and a cyclone with 10" inlet and outlet. There is no name plate on anything exept the Motor which says siemens. Alot of what I've been reading is geared toward 6" and 4" systems. I have some questions.

1. Does it matter whether you push or pull air through a cyclone?

2. Do I have to maintain 9" or 10" for my main line? If so how would I do my drops?

3. My tools are 10" ts, 12" planer, 6" jointer, crapsman lathe and radial arm saw. Routers and such.
Is it possible that this collector is to big for my system? Obviously I want bigger tools in the future. But my main line will only run about 30'.

Ty

Erin Patton

[Bruce Seidner]

I think this is much to big for your needs and you should give it to me. I will arrange for the shipping if you will have it crated and ready to go at your earliest convenience. I will begin manufacturing yard sticks which I can finish very quickly with this size belt sander. The DC system sounds like it is scaled like other commercial systems I have looked into to get ideas for my home hobby shop. If there is only one machine on at a time with one operator in the shop then I think it makes sense to keep all the mains 9" and your cyclone is also to scale. Nothing to do but duct the exhaust out doors or if you are unable then talk to the good people at Wynn or American Fabric about indoor filter options. There seems to be no coincidence in this pairing of industrial sander and blower/cyclone. It is wild to see the dust that comes off a 6" wide belt sander. You will have desert storm on your hands without a competent DC and that sounds like what you have. Well, if you have 3phase into your shop. You do have 3phase into your shop, don't you? Given the scale of most hobby or small cabinet shops 6" duct seems to be the sweet spot in cost and efficiency. I have recently been setting up 8" main ducts, consistent with the inlet of my blower in the new system with 6" wyes that come down to the machines. Once down to the machine I have found it interesting to use smaller wyes to split the intake between the top and bottom of most of my machines and there is lots of creative thinking and examples of hoods. Hoods are without question the place where we are all really scratching heads and experimenting with options. Best of luck, keep reading and drawing and experimenting. Don't glue anything because it will change soon enough.

[Jim Andrew]

Also have a widebelt, although it is a very small open end machine, but amazing what it will do. Get some 60 grit belts, and you can grind your panels down with it, and use it to flatten them. What I do is surface to 7/8" then glue up panels, and grind down to 3/4 plus, then switch to a 120 grit to finish them, then of course use ros to fine sand. I just turn the panel over and over as I run through the sander, and pretty soon they are flat as anything.

[David Kumm]

Erin, will you run off a vfd or a phase converter? If using a rpc you won't be able to adjust the speed so the 15" fan if a straight blade radial will pull about the full amps if run with a 10" inlet and not filters. You can go 10 or 9" on the mains although you need to be careful to put large machine ports in. The belt sander needs all the flow and you don't want to run 4" ports one at a time as the flow in the mains will get too slow. You have a commercial type system that will run about 2000+ cfm so you are golden if you have the amps to run it. If you don't need the full cfm 8" spiral will restrict it down to about 1600-1800 cfm and run the motor more like at 6 hp. The straight blade will be less efficient at low SP but at higher restriction will outperform the more efficient backward inclined fans so velocity in a 6" port will be at 6000-7000 fpm- at least. Doesn't matter if push or pull if the blades are heavy steel but would not put backward inclined or barkward curved aluminum fans in front of the cyclone. You will appreciate your system with the belt sander and if you don't trade to Bruce I've got a 5 hp three phase blower I'll trade for. Dave

[erin patton]

Ty for the replys! Dave I'm also in the process of hooking up a 40hp rpc. This collector was used with the sander and other equipment. It has straight steel blades. The wbs is also 3ph and is an older Taiwanese unit. The thing that I can't figure out is that it only has just one 4" dust port. I may be in for a surprise when everything is up and running. so should be fine to run 9"'or. 10" and then 6" for my drops?

Erin

[David Kumm]

Ty for the replys! Dave I'm also in the process of hooking up a 40hp rpc. This collector was used with the sander and other equipment. It has straight steel blades. The wbs is also 3ph and is an older Taiwanese unit. The thing that I can't figure out is that it only has just one 4" dust port. I may be in for a surprise when everything is up and running. so should be fine to run 9"'or. 10" and then 6" for my drops?

Erin

I would put at least a second 4" port on the WBS. You will need it. If you don't use filters I would go down to 8" to restrict the motor. If you use filters you want at least 200 sq ft and 300 would be better. If you have two 4" on the
WB you want a 7" flex to a boot wye 4x4x7 for some extra velocity to the ports. I have 6" to two 4" on my Performax and more would be better. What is the make of the DC? Dave

[erin patton]

I would put at least a second 4" port on the WBS. You will need it. If you don't use filters I would go down to 8" to restrict the motor. If you use filters you want at least 200 sq ft and 300 would be better. If you have two 4" on the
WB you want a 7" flex to a boot wye 4x4x7 for some extra velocity to the ports. I have 6" to two 4" on my Performax and more would be better. What is the make of the DC? Dave

I forgot to mention that the dc came With 6 filter bags and a box made out of particle board that they mount on. The dc has no markings that I can see. It would be nice to know who manufactured it.

Would you put the cyclone in front or behind the blower?

[David Kumm]

My blower is in the attic above my shop and behind the cyclone. You can go either way but blowers are loud so anywhere that reduces noise is a good deal. The filter tubes may or may not be good any longer but i like tubes as they are easier to clean. I run 4 8' x 12" tubes and one cartridge filter. You have enough power to not have to worry about the extra bends you will have with the separation. Dave

[erin patton]

Will 26 Gage duct work? I have just been pricing spiral at Menards and man its salty!!

[ian maybury]

David may have noticed stuff that I haven't, but a 7.5HP motor is larger than a typical BC bladed impeller would need at 15in dia. So if the motor is correctly sized he's probably right that it's a radial blade impeller - probably one with fairly deep blades. Which will move more air and be be a bit noisier than a smaller bladed BC item. If it's a deep bladed type it may not want to do much above 12in WG, so shortish duct runs are no harm.

It's worth measuring the blade height and checking out the type, as that would allow picking numbers off e.g. a Cincinatti Fan curve for an impeller which should be close. It could have quite a significant effect in terms of the duct sizing that would suit it best, and the pressure capability of the fan. Take a look at Cincinatti Fan's .pdf catalogue for their SPB fans to see what the curves (in table form) and blade types look like.

The 'too big' question might arise if you had a machine you needed to run from the system that would only allow a very low airflow - and your ducting was sized large to maximise the flow for the largest of your requirements. (the sander, the RAS and the lathe are all big users) You would only run into trouble if the smallest requirements (machines with restrictive hoods etc) were creating so much restriction as to not allow the moving of the air in your mains fast enough to give safe dust transportation. This problem could be solved by bleeding in air from another branch, but only at the expense of dropping what would already be a slightly marginal level of suction through the small machine.

e.g 10in duct = 0.545ft sq cross section area. ft/min @ 1,000CFM (still quite a decent level of flow) = CFM/ft sq = 1,830ft/min This realistically is too low for safe transportation, certainly in verticals.

It may be that the main duct size can be optimised to suit your situation. Reducing the main duct size would make it more tolerant of reduced CFM in one set up at the expense of reducing your CFM through a full bore main duct run all the way to one of the big users. There will in effect be a maximum 'turndown' or ratio of highest to lowest flow that the system will handle anyway - with the lowest possible (for a given branch size and length) being determined by the in WG max suction the fan can develop.

It's best to pull through the cyclone as this drops out solids before the fan, although with the right impeller and some care it can be done the other way.

It'd be interesting to see some dimensions and internal configuration details for your cyclone. There's not a lot of data around for their retention performance on fine dust, but it would at least enable confirmation that it was broadly of the taller industrial pattern that's known to work.

Don't forget to think through your filtration requirements. If you are recirculating into the shop and not exhausting outside (as this system very likely was in common with most industrial set ups) you are likely to need HEPA cartridges. Bags typically leak the dangerous fine dust, or at least only work properly for a narrow time window between 'running in' and becoming highly restrictive.

ian

[David Kumm]

Call around to the HVAC guys in town as they sell spiral cheaper and may have some laying around, particularly in the 8-10" sizes from commercial jobs. The pipe and fittings will cost you but worth it for ease of installation. 26 ga will work although the larger duct is often 24. I don't think I would go 10" unless you have long runs and big machines. You really don't need the full cfm. That setup will deliver 2000+ cfm in an 8" main. Dave

[erin patton]

Thanks guys! Ian I looked on the cincinnati web site and it looks more like the PBS style with standard blades. I'll try and post some pics later on.

Ty
Erin

[ian maybury]

+1 on what David says about buying your spiral from a manufacturing HVAC fabrication outfit - rather than a retailer who will have another mark up bunged in there. Over here spiral bought that way is quite a bit cheaper than PVC.....

ian

[jim gossage]

+1 on adding a second port to ur WBS. DC on my 18" wbs was mediocre w one port, but now dust free after adding a second one. It took about 3-4 hours to design and fabricate the second port.

[erin patton]

Hey jim thanks for the advice!!! Anyway I can see your mod? At some point I'll have to add some ports. What would 3 4" ports be = to? 7"?

Also I found a name plate on the back side of the blower. General blower co. Is the name. They went out of business in 1959!!! Old blower unit!!
Erin

[ian maybury]

When branching ducts it's basically a matter of the two (or three) branches not exceeding the cross sectional area (area of the inside circle) of the main. if you fan has plenty of puff and the air speed in the main is good (approaching at least 4,000ft/min) then it's probably not necessary to be too fussy about it. Maybe go the size above if you have plenty of speed, the size below if it's a bit marginal.

An 8in dia duct has .349ft sq, and a 4in has .087ft sq. So it should be possible to run x3 4in branches from it if the airspeed in the 8in is decent. i.e. above say 1,200CFM. Some care would be needed in laying out the branches to ensure that one or more branch wasn't starved as a result of there being a lot more pressure drop/flow resistance for the air being pulled through that one.

ian

[erin patton]

Ty Ian, I appreciate the help so far from everyone.

Its looking like spiral pipe will be to expensive to run. What would be a more economical choice with decent fitting options for me? Any good vids or pics of peoples systems I could see?

Ty

Erin

[David Kumm]

Ty Ian, I appreciate the help so far from everyone.

Its looking like spiral pipe will be to expensive to run. What would be a more economical choice with decent fitting options for me? Any good vids or pics of peoples systems I could see?

Ty

Erin

The pipe is cheap compared to the fittings. Kencraft has pretty decent prices but they add up quickly. You don't want pvc 6" with that blower or you will blow your eardrums out. Sometimes you can find use fittings on CL but they are not easy to ship so there will be some cost. Buying pipe and fittings for a 7.5 hp system is a little like fixing a Ferarri. Dave

[Michael W. Clark]

Erin,
Maybe this has already been covered, but I think you want to keep your CFM up even when you are running the other machines that require less flow. I'm assuming the cyclone/fan combination was sized for the 36" WBS, which is probably your biggest CFM user. The other tools don't need as much CFM and a 6" duct should be more than adequate to them. However, if you only have a 6" duct open, your volume may drop down and that will dramatically reduce your cyclone efficiency. This will cause your afterfilters to plug or result in more dust carryover to the outside (maybe this is not a problem?)

Let's say you come out of the cyclone with an 8" duct. You could put in an 8x8x8 wye. One branch would go to the WBS and the other branch would split into two 6" ducts. One 6" duct would go to the rest of your machines and the other would have a blast gate to be used as a bleed. I'm assuming only one machine will run at a time. Most of the air will try to come through the bleed, so you would close the blast gate on it until you have good collection at your longest run. You may have to have a couple of settings for the bleed, but one will probably work fine.

You could possibly connect the bleed to a home-made filterbox and use it as an air cleaner.

Mike

[erin patton]

Man there are alot of options!! I'm going to have to rethink this. You have good ideas mike and I like the filter tip also. I hate to say it but I might be more confused now than ever!!!

[Michael W. Clark]

Man there are alot of options!! I'm going to have to rethink this. You have good ideas mike and I like the filter tip also. I hate to say it but I might be more confused now than ever!!!

Erin, I apologize, that was definitely not the intent if I caused any confusion. I think I would keep the big system as you probably want it with the WBS. However, you probably don't need all the airflow when you are running your other machines. Plus, you don't want to run larger duct than you have to due to space restrictions and cost. But, you need the flow at the cyclone to keep the efficiency up. If you are discharging outside without filters, and you don't mind some extra chips outside the shop, then don't worry about it. Plumb the duct as you want and let it fly. Enjoy your new sander and go make some furniture.

Also, +1 for putting the fan on the downstream side of the cyclone. It doesn't affect performance, the cyclone doesn't care, but it reduces the amount of material going throuhg the fan. Also, it keeps your cyclone under negative pressure. If you have any leaks in your flanges or dust bin, the dust will stay in the system and not be blown all over the shop.

I would post a sketch about the gate arrangement, but I don't know how to post a file. I can scan in a hand sketch, but I can only upload it as a picture file. The last time I tried it, it was unreadable and useless.

Mike

[David Kumm]

Erin, your system is so powerful it will likely pull 9000 fpm through a 4" port so airflow won't be much of a problem but to be safe whenever I have a 4" port to a machine or floor sweep hose I drop with 6" and put the gate - if convenient on the 6" before a 6x4x4 wye and then you are always running a drop with 2 4" gates open. That will eliminate pretty much all your problems. Takes extra gates if you want more flexibility but 4" gates are cheap. Keep reading and learning. It starts to make sense and then you find it is even more complicated and you need to learn more. Kind of fun to study though. The CF cfm data is pretty cool, especially if you look both at the 2850 and 3450 rpm numbers for each type of fan. Dave

[erin patton]

Hey mike, no need for an apology. There has been alot of great info from everybody. Better to have as much info as possible so that its done correctly the first time.

Right now I'm thinking that I'll reduce down to 8" and run an L shape main. 15' 90* 15' then reduce to 6" to pick up the ras and possibly a floor sweep. Off of my main I'll drop 2 6" legs. One with 6x6x6 wye with blast gates at each wye. One will pick up the wbs and the other the table saw. The second leg in the same configuration to pick up planer and jointer. I just might add a wye at the start of the main for future needs and for an air cleaner. I'm going to have to mod about all the machines to exept 6" equivalent.

See anything wrong sofar?

Erin

[David Kumm]

With a 7.5 hp blower I would stay with 8" all the way. Air is going to whistle through the 6" main and a year or two from now you will move or change a machine and change the smaller main anyway. Ask me how often that has happened. Dave

[Michael W. Clark]

I don't know what the cost of 8" S&D is, but you will probably be better off with metal duct at some point, especially by the time you consider the fitting costs. I think David's system is 8", not sure what material he used. I'm in the process of upgrading to 6" and the fittings are more expensive than the duct (S&D).

[erin patton]

The main will be all 8". At the end will reduce down to a third leg, I didn't phrase it very well the first time, sorry about that. Maybe I should use a wye at the end instead of a reducer.

I need to do more research on the s&d pipe. If it's more economic I might think about using it. Not sure of the fittings though. With plastic do you ground or not ground? There seems to be different opinions about this subject.

Erin

[Michael W. Clark]

With plastic do you ground or not ground? There seems to be different opinions about this subject.

Your are going to open up a can of worms there. I have my opinions (backed somewhat by facts). Technically you can't "ground" the plastic because it is not a conductor. You can give the static charge a shorter path to ground by wrapping the duct with wire or running a wire through it, then attaching that wire to a ground. There are different methods to doing this. The main reason for doing it is to prevent plugs and to prevent nasty zaps. The metal duct can zap you too, but it can be "bonded and grounded" because it is a conductor. There are additional reasons its done in industrial systems, but those are the primary reasons for home use.

Mike

[erin patton]

What is a good source for 8" s&d pipe and fittings?

Erin

[Jim Andrew]

Have a thought. Stove flue pipe is heavier than duct. Don't know gauge, but considerable. This is spring, and stores might be closing out their 8" and 6" stove pipe. So you might make a buy on some fittings. I use couplings from Kencraft to go from spiral to the snaplock fittings, and to put spiral end to end. Some fittings fit and others need a little adjustment. A crimping tool comes in handy. But don't try to crimp spiral.

[David Kumm]

Actually crimping spiral isn't all that bad when it avoids an additional fitting. Keep in mind that you are trying to keep the fittings so the air flows with them rather than chips hanging up on them. You don't want to get real aggresive with the crimper but just enough to get it inside the fitting. I've had best luck with Oneida and Kencraft although there can be some inconsistency. Some fittings are inside inside but i prefer the inside outside ones and think metal is the way to go with larger sizes. You can work with 8" spiral yourself and change it when necessary. The blower is likely sized to fit metal duct. Dave

[Michael W. Clark]

What is the best way to transition between spiral,crimp, hose, and S&D?

Pardon me for asking this on your post Erin, but you will probably run into this too.

[erin patton]

No prob!! I went to Menards tonight and they had only 8" sheet metal pipe, no fittings. Limited 6" stuff also. Would what they call STD Gage work if I used 2' sections? This way it won't be so weak.

As far as s&d pipe I have yet to find any 8x8x6 wyes, and or saddles.

Anyone feel free to keep this thread alive!!!

Erin

[erin patton]

Dc update

Tonight I just got about 100' of 7" duct free from my dad. It's seem to be about 24 or 26 Gage. I'm going to try and incorporate this in my system. Any thoughts from anyone how far I can go with it? It would be nice to use as much as possible.

Erin

[Michael W. Clark]

Erin, I would try it, especially for all your other tools. You may want a little larger duct for the WBS. If your fan surges or you get a lot of carryover, you can put a bleed in the system to bring in a little more air for the fan and cyclone.

[erin patton]

Im going to try it! I also have about 10' of 8" to throw in there. Hopefully this will work and with save me some money along the way.

Erin

[Jim Andrew]

I find a crimping tool very handy. And sometimes have to hammer out crimps on an existing piece. After you have had your system for a while, and you need to change things, you find you have a few extra parts, and I just use them if possible.