Exhausting Cyclone Outside

[John Karam]

So I have narrowed down my choice of cyclone systems to the Oneida 2 HP 13.5 inch impeller Dust Gorrilla or the Penn State 2 HP 14 inch impeller Tempest. From my understanding they are in different leagues so to speak.
http://www.oneida-air.com/newsite/gorilla_2hp.php
http://www.pennstateind.com/store/temp142.html

The reason Im considering either is because I'm exhausting my system outside of my shop, so I will not need a filter. Since the cyclone no longer has to be "perfect" and just has to be good enough to suck up all the chips at the machines, I'm thinking maybe I can get by with a cheaper system, the Tempest. Let me know if theres a flaw in my thinking here please. :)

My questions are as follows:
Do you guys know if a cyclone is made louder or quieter by ducting outside?
Besides losing heat or cooling, are there any negatives to ducting outside?
Are CMF ratings improved by not having a filter?
Also, by going this route, would a Tempest be more comparable to the Gorrilla? I do not wish to sacrifice the overall performance of the system.

Thanks folks for the help, I really appreciate it!

[Andrew Nemeth]

I'm no expert but I do believe that you do need to be careful ducting directly outside if you have any other vent leading outside. If for example you have a gas furnace or water heater that vents outside you can lower the pressure in the building enough to cause a backdraft of exhaust (including carbon monoxide) into the building. The same would hold true for a spraybooth. The solution would be to make sure you have adaquate supply of freshair coming into the building to compensate for that which is lost. An easy test for this is to fire up the collector and then hold a lit candle near the concerned vents and see if the flame is pulled towards the vent or back towards the inside of the building. Again, I'm not an expert but it is something that I have thought about a bit.

Hope this helps,

Andrew

[James Mudler]

Something to think about. Will you ever move?

I could vent outside today, but if I ever moved into a neighborhood I am willing to bet I would not be well liked. Risk of poor performance due to saving money if the venting/filtering arrangement could change would steer me to buy the better unit because I could do both vent or filter and have good performance.

Duct collection is your lungs. I haven't found a lung on ebay yet :p

[Dale Lesak]

I think I'd check with your neighbors and the EPA be for I did anything like that. Just to be on the safe side. The exhaust will have very fine wood particles and (Might"??) be explosive.:confused: Just my two C's

[Chris Padilla]

If your neighbors do not complain, I'd say do it...no big deal. Yes, it should be quieter venting outside. Lots of us put mufflers on our filtered outputs to help with noise.

A well-designed cyclone shouldn't emit too much stuff through its exhaust anyway but be sure to point the output down so you don't collect water in the exhaust pipe. I believe Steve Clardy, a regular here, does this very thing.

[Matt Meiser]

Lots of us vent outside without issues. If your building was really tight, you draw makeup air in through the flue of a gas appliance causing CO builidup. Mine apparently isn't as it hasn't shut down on improper flue pressure and my CO alarm hasn't gone off. Theoretically you also cause cold outside air to be drawn in raising your heating bills. Again, no problems there--my propane usage was the same the year before and year after I switched. In a hobby shop the cyclone runs very infrequently in the big scheme of things. Some dust goes outside with my setup as the separation isn't perfect, but 99% of the time the prevailing wind blows it towards an open field.

[Terry Sparks]

I have a 24 X 28 foot shop that I use to build cabinets and many times, having enough space in the shop becomes an issue. To solve that issue I have built a small sound insulated storage shed behind my shop that houses my compressor and with a partition, my DC. With the DC portion of the shed is a 15" attic fan that is mounted above the DC to exaust the dirty air to the outside of the shed and is wired to turn on with the DC. Beyond the space savings, I no longer need the 1 micron bags and the shop is much quieter, which is an added bonus to what I used to have.

If you have an issue with negitive pressure drawing air away from your furnace ( I don't, my shop doesn't need to be heated) one solution is to wire a second fan to start up and blow clean air into your shop when the DC is turned on.

[Rod Sheridan]

Hi John,

- the airflow of the cyclone could be increased by removing the filter IF the motor load does not increase past rated current. You would have to measure this after installation and provide a restrictor if the motor is overloaded

- the cyclone will be less noisy inside the shop if vented outside, however the airflow can be quite turbulent as it exits the cyclone, which can cause additional exterior noise.

- you don't mention if there are any local ordinances against this, or if you are in a residential, commercial or rural area. Your neighbours may have legal recourse if they object to the noise and/or you have run afoul of local bylaws.

- exhausting somewhere in the order of 1,200 cfm will mean that if it was in a house with 1,200 square feet of floor area in addition to a basement, you would be replacing all the air in the house every 16 minutes. This would be far in excess of what any residential heating or cooling system could handle.

- combustion air must be provided for any fuel burning appliance, and exhausting this much air can cause reverse drafts in flues.


Regards, Rod.

[Sean Troy]

So I have narrowed down my choice of cyclone systems to the Oneida 2 HP 13.5 inch impeller Dust Gorrilla or the Penn State 2 HP 14 inch impeller Tempest. From my understanding they are in different leagues so to speak.
http://www.oneida-air.com/newsite/gorilla_2hp.php
http://www.pennstateind.com/store/temp142.html

The reason Im considering either is because I'm exhausting my system outside of my shop, so I will not need a filter. Since the cyclone no longer has to be "perfect" and just has to be good enough to suck up all the chips at the machines, I'm thinking maybe I can get by with a cheaper system, the Tempest. Let me know if theres a flaw in my thinking here please. :)

My questions are as follows:
Do you guys know if a cyclone is made louder or quieter by ducting outside?
Besides losing heat or cooling, are there any negatives to ducting outside?
Are CMF ratings improved by not having a filter?
Also, by going this route, would a Tempest be more comparable to the Gorrilla? I do not wish to sacrifice the overall performance of the system.

Thanks folks for the help, I really appreciate it!

You won't go wrong with either one. I have the Tempest and a neighbor has the Dust Gorilla and I'll be darned if I notice any difference.

[John Karam]

More specifics of my site.

The shop is in a stand alone structure with no heating or cooling ventilation of any sort, so there is no gas fumes to worry about. Also, neighbors are few and far between so I know they wont have a problem with it. (A near by lot actually has large exhaust fans in use on a regular basis).

You all have brought up good points for me to consider, thanks for the advice!

Are there any thoughts on the Gorrilla or Tempest question?

[John Karam]

Sean- Is Tempest and Gorrilla the same models I have linked to? Also, on the Tempest, are you running any large tools on it with long duct runs (I'm looking at around 20 feet for my runs) such as a planer (20inch)?

[Sean Troy]

I'm using it for my Table Saw, Planer, Jointer, miter saw, downdraft table, band saw and then some. The ones I'm refering two areboth 2hp but the tempest has a 14" impeller as opposed to the 13.5" for
the dust gorilla what ever difference that makes. My longest run is 40 ft.

[Chris Padilla]

Do yourself a favor and put in a floor sweep...very handy...sucks up wood, bugs, small mammals including kids, aprons, pencils, nuts, bolts.... ;)

[Jim Becker]

I own an Oneida system because they only do dust collection and their systems are purpose built, including critical items like the impeller. The current Tempest is a much better product than originally, but I'm not sure how much research and continual engineering PSI does compared to a dedicated DC company--PSI is a mass-marketer. This link (http://www.oneida-air.com/newsite/gallery.php) at Oneida may be helpful, although they are listing a 2.5hp Tempest, rather than the 2 hp you are showing...they may or may not be the same system.

The collection bin is also smaller than the standard Oneida setup...and preferably, you'll want to move up to a 55 gallon drum if you have the headroom to do so, regardless of which system you choose. Trust me, you can fill it quick with some serious face jointing and thickness. planing!

[Sean Troy]

I own an Oneida system because they only do dust collection and their systems are purpose built, including critical items like the impeller. The current Tempest is a much better product than originally, but I'm not sure how much research and continual engineering PSI does compared to a dedicated DC company--PSI is a mass-marketer. This link (http://www.oneida-air.com/newsite/gallery.php) at Oneida may be helpful, although they are listing a 2.5hp Tempest, rather than the 2 hp you are showing...they may or may not be the same system.

The collection bin is also smaller than the standard Oneida setup...and preferably, you'll want to move up to a 55 gallon drum if you have the headroom to do so, regardless of which system you choose. Trust me, you can fill it quick with some serious face jointing and thickness. planing!

The S series tempest is the 2.5 HP unit. Mine is the 142 CX. There is no doubt about it, Oneida makes a top notch system. For me, price was a serious consideration when I purchased mine as I was setting up a new shop ( as if I'll ever be done setting up )and had other tools to purchase. Bill at Penn State was most helpful in answering questions each time I called him. Service is important to me also. I can't speak about Oneida's service because I never delt with them.

[Cliff Rohrabacher]

Check local code.

[Larry Fox]

Do yourself a favor and put in a floor sweep...very handy...sucks up wood, bugs, small mammals including kids, aprons, pencils, nuts, bolts.... ;)

Not to disagree with Chris but I would recommend avoiding a floor-sweep. They are way cool but it is my understanding that they could also present a fire hazard as you are likely to suck up something metal. Something metal hitting the impeler could cause a spark. A spark could cause a fire.

Just my $0.02.

[Jim O'Dell]

I exhaust my Clear Vue outside. My outlet is an 8-6-6 metal wye with 2 6" louvered outlets, think dryer outlets with the flaps, that exit one gable end just under the eaves. See post #83 here for some pictures: http://www.sawmillcreek.org/showthread.php?t=14427&page=3&highlight=coolmeadow+creations
or click this link for the louver only picture. http://www.sawmillcreek.org/attachment.php?attachmentid=50470&thumb=1&d=1163984311
My system is about as loud as my contractor saw, BS or router table in the shop. Outside it sounds like a small turbine engine whine. I'm in an area where most lots are about an acre, and no one has complained. But I don't run it past 8:00 at night, and rarely past 6:00, and never before about 9:30 in the mornings. I've never noticed any deposits outside, but then again, I haven't overfilled the barrel....yet! :D
Bill Pentz recommends exhausting outside for those that can. All warnings about open pilot flames listed above apply. Sounds like that won't be a problem for you, as it's not for me. Jim.

[Jim Becker]

Not to disagree with Chris but I would recommend avoiding a floor-sweep. They are way cool but it is my understanding that they could also present a fire hazard as you are likely to suck up something metal. Something metal hitting the impeler could cause a spark. A spark could cause a fire.

The impeller is not in play with a cyclone as it comes after the separation. Floor sweeps should only be used with a cyclone for that reason. I have three and wouldn't give them up for anything. Norm Abram has even said that the floor sweep is the best part of his dust collection system...(quote/paraphrase on the Air-Handling Systems web site)

Even with the great performance of my system, it doesn't tend to pull things like screws up the drop...they just rattle around while it's running and then fall out when the air flow is shut off.

[Ken Lutes]

I use to return into the shop and finally decided that it wasnt worth the trouble of dealing with the filters and super fine dust that made its way thur the filter. The fine dust in my opinion is what you dont want. I vent all my power tools and the filters had to be cleaned quite often. I built a 4 by 8 room adjacent to my shop and vent into it. I put a screen opening in the room to not build pressure. I have a lot cleaner shop and less hassel now. I am glad that I did.

[Larry Fox]

The impeller is not in play with a cyclone as it comes after the separation.

Duh - yep, true. I guess I was thinking of the baggie models. :)

[John Karam]

Thanks for the advice everyone, Im pretty sure Im going to order the Oneida now. Just trying to figure out if i will place the whole unit outside and built a shed for it or not.


Thanks again :)

[Stan Welborn]

I also vent my ClearVue outside. I built my exhaust out of ply (about a foot sq) to run down the wall and vent out a grate behind a central air unit in the rear of my shop. It was a little loud outside so I lined the outlet box with eggshell foam. I knew the exhaust was plenty big so there would be no back pressure problems. Major difference that made. Now I don't worry about disturbing any neighbors. Fresh air gets sucked in the exhaust fans in my paint bay then backwards through the filters into the main shop. Long as I don't paint and saw at the same time I shouldn't implode my shop.:D

As for floor sweeps, I have two and thinking seriously about adding two more. Love em.

[Rick Potter]

Hi John,

At my old house I had an Onieda 1 1/2 HP cyclone with the internal filter. The first time the filter needed cleaning I decided it was way to hard to remove and replace, what with my bad shoulder, so I just left it out and vented to the outside. I was very surprised that it did not run any quieter (this unit was really loud either way). It worked out fine, and I never had a coating of dust on the brick and stucco where it exited.

I am now considering a 3 HP cyclone for my new shop, so I e-mailed
Onieda and asked some questions:

1. Q: Will the unit be quieter if it is vented outside?
A: No, it will be slightly louder because the unit has a built in muffler as part of the filter.

2. Q: Will there be any problem with the unit when you vent it outside?
A: No, it will be fine.

3. Q: How much money will I save, buying the unit without the filter?
A: About $100.

I have not decided which way to go yet

Rick Potter

[Tom Joad]

would it be worthwhile to attach a magnet somewhere in the DC system to catch any steel that might be picked up?

[Tom Joad]

In this kind of weather I wonder how much more it would cost to keep the shop heated venting the amount of heated air that a dust collector is pushing outside, the dust collectors that you have described move about 1000 CFM. by moving that much air outside every minute wouldn't you also reduce the humidity level in the shop significantly? dry air is harder to heat

[Stan Welborn]

would it be worthwhile to attach a magnet somewhere in the DC system to catch any steel that might be picked up?
Ok, maybe I'm a little slow this morning, but why do you need to catch the metal? My floor sweeps regularly pick up dropped screws, nuts, and all kinds of stuff and throw it right in the dust barrel with everything else. I guess if you're trying to keep the metal out for use as bedding for animals or yard filler or something where it would cause problems it would be an issue, but I just dump mine in a hollow in the woods.

[John Thompson]

I looked at the Tempest you are considering compared to the Tempest S 2 1/2 HP for the cost factor. I paid the extra for the Tempest "S" as they improved the impellor design.. extra 1/2 HP and it has a twin-stacked cartriage filter.

I don't regret that decision either as it performs very well with 20" planer, 8" jointer.. 18" BS and a Uni-saw. If at all possible.. save and pay the extra and get more HP and more filter area. I don't think that would be a decision that you would regret. You will get the $245 difference in cost refunded with performance, IMO.

Sarge..

[Bill Pentz]

John,

Do you guys know if a cyclone is made louder or quieter by ducting outside? The noise inside your shop will be less as most of the cyclone noise is created by the blower and is transmitted by the outgoing air stream. Insulating the blower (not motor) and its outlet pipe will help considerably, plus making the outlet pipe huge will also cut way back on the higher pitched noises. You may also want to run the output through a muffler before venting outside.

Besides losing heat or cooling, are there any negatives to ducting outside? There will be a big cooling loss if you air condition your shop. Most unless they are working with outside temperatures well below freezing don’t have a heating problem. Just use IR type radiant heaters that heat directly without having to warm the air. The only other issue was well covered and that is the danger of drawing carbon monoxide backward through your vents.

Are CFM ratings improved by not having a filter? Cubic Feet Per Minute (CFM) ratings are improved greatly. A typical 2 hp cyclone with seasoned filter will have 6.0” to 10" of static pressure resistance when connecting to your tools with 6” duct. That resistance for a typical 14” backward curved BC impeller will allow a maximum airflow of about 1270 CFM and pull a mere 2.7 hp. Throwing away the filter will decrease resistance down to as low as 3" which bumps the airflow to about 1601 CFM. That also increases your motor draw to 3.24 hp because the more air we move the more work your motor must do. So a 2 hp motor will soon let the smoke out. Since standard motor sizes come in either 3 or 5 hp, I have long recommended only using 5 hp motors on cyclones. For sure you need to use an amp meter and verify that your motor is not pulling more than its maximum amps when moving the most air.

Also, by going this route, would a Tempest be more comparable to the Gorilla? I do not wish to sacrifice the overall performance of the system. Overall performance of a cyclone system is defined by blower efficiency, cyclone resistance, cyclone overhead, filter resistance, ducting efficiency, and hood overhead. Most of the major brands of cyclones being sold today follow my 1999 cyclone modification recommendations except for JDS who did their own thing and Clear Vue Cyclones which uses my more current design. That older design is fairly efficient in terms of cyclone resistance but was just not good enough to use with fine filters so I came up with a roughly five times more efficient separator. You hear little about separation efficiency, but without good separation efficiency you either have to use wide open filters that pass the 10-micron and finer dust right through or deal with a constant filter cleaning problem.

“What is my goal?” Unless you also ask this question, you missed the most important question a woodworker needs to ask themselves when thinking about dust collection. If your goal is chip collection meaning keeping your work surfaces and floors clear of the same sawdust and chips that you would otherwise sweep up with a broom, then you can look at a good CFM Requirements table and find almost all stationary small shop tools are well serviced by an airflow of 350 cubic feet per minute (CFM) which works out to an ideal duct size of 4” with a 4000 feet per minute airspeed which is near optimal to keep our vertical ducts from plugging.

If you want to also collect the fine airborne dust then you can look at a CFM requirements table (http://billpentz.com/woodworking/cyclone/DC4Dummies.cfm#CFMRequirementsTable)or compute one for yourself and see that different air quality levels require moving different amounts of air. To meet the 1989 OSHA air quality levels roughly 800 CFM is required at our larger stationary tools. To meet the five times tougher American Conference of Governmental Hygienists (ACGIH) air engineers found we need to move about 900 CFM at these same larger stationary tools. To meet medical recommendations which are a European standard and well below the recently released EPA standard we need to move a real 1000 CFM at our larger stationary small shop tools. To move that much air we need to size our blower.

By the time we are ready to spend enough to buy a cyclone based dust collection system most are tired of cleaning out dust collector filters and emptying dust collector bins. All cyclones will be a big help on emptying dust bins, but that is just not the case with filters. Most cyclones push almost all the fine dust right into the filters so the filter cleaning problem continues unless you buy a wide open filter that simply passes the finest invisible 10-micron and smaller dust particles into our shop air. I like your venting outside and do the same myself except in the worst weather.

To size a blower we need to know how much air we want to move (1000 CFM) and the typical overhead resistance of our ducting, tool hoods, cyclone, and filter. You can use a good static pressure calculator such as the Static Pressure Calculator (http://www.billpentz.com/cyclone/staticcalc.xls)on my web pages and it will show the worst case typical resistance in a two car garage sized small shop with a cyclone based collector is about 10.15” and the least resistance is with clean new filters and a minimum length run of about 6.5”. Blower technology is mature so looking at just about any good fan table for the same size impeller turning at the same speed will give you near identical airflows and show what size impeller and horsepower motor you need. Those who claim far more airflow than one of these tables are either fudging their numbers or using a totally different kind of blower impeller. I know of no small shop vendors now using anything other than standard backward curved impellers and all but one uses heavy steel impellers. The backward curved impellers make less noise. The steel can handle material hits because just like a dust collector all goes right through the blower bashing into the impeller if you should let your dust bin get full. Most of us make this mistake fairly regularly until we get tired of cleaning chips out of our filters and come up with a way to know when our bin is near full.

To size the impeller look at a good fan table such as the Cincinnati Fan Pressure Blower fan table (http://www.cincinnatifan.com/catalogs/PB-1102-internet.pdf). This table shows the first impeller that moves over 1000 CFM at 10” of resistance is a 15.5” diameter impeller with a 3.5” blade height and 6” ducting opening. With a little reading between the lines we can see we need a roughly 15” diameter backward curved (BC) impeller with a 5” blade height. Most small shop dust collection cyclones only use a 14” or smaller diameter impeller. Looking at this same table shows a 14” impeller is only going to move 602 CFM at 10” resistance and pull 1.88 hp.

To size our cyclone motor we next again either hand calculate or use a static pressure calculator to estimate the lowest resistance. The lowest resistance will be when the motor is moving the most air and drawing the most horsepower. Typically we have the lowest resistance when we have a big connection right next to the cyclone with a single port such as a big planner. Our static calculator will cut the overall resistance down to about 6.5” static pressure. Looking at the entry for 6” shows our 15.5” diameter impeller moving 1628 CFM pulling a whopping 4.5 hp. Because our induction motors used to power cyclones are real compressor duty, meaning made to handle 6 times or greater startup loads, even a 2 hp motor can move this much air for a while. Eventually the motor will overheat and become history. Using a 14” BC impeller and looking at this same table with 6” inlet (ducting size) we end up drawing 9.7 hp and moving 952 CFM airflow.

bill pentz

[John Karam]

Thank you for your response Bill, I appreciate it.

From reading all this, what I am understanding is that by venting outside a 2 hp motor is more likely to burn out because there is no filter creating the resistance that will keep it from exceeding its spec'd amp draw. Is this correct?

If this is the case, is there anyway to prevent that from happening? So the motor does not burn out.

Thanks again

[Bill Pentz]

John,

Use an amp meter and ensure that the amps do not go over the motor capacity. If they do, use a blast gate in front of the cyclone and with your most open air configuration, slowly close that gate watching the amp meter until the amps are less than the motor rating. If you had this problem with a filter which is not the case with your venting outside, you would retest after about 3-4 filter cleanings. At that point the filter resistance would increase from the particles that get trapped in the filter matrix allowing you to readjust the blast gate to be more open.

Remember that failing to move enough air means the dust you miss should be addressed with regular thorough shop cleanings and use of a good dual cartridge respirator mask.

Hope this helps..

[John Karam]

So I could use one of the blast gates from one of the machines and open it to a certain point to achieve the right sort of resistance that would keep the amps to where the motor is rated for?

[Bill Pentz]

So I could use one of the blast gates from one of the machines and open it to a certain point to achieve the right sort of resistance that would keep the amps to where the motor is rated for?

Yes. That would work. I suggest you use a good quality metal gate with the screw to hold the gate open to a consistent size.

[John Karam]

Alright, great. Thanks for the advice Bill. I really appreciate you taking the time to help me out on here and all your efforts on your site.