6" pipe with my Delta dust collector?

I've been reading through Bill's Cyclone dust collector site, (http://cnets.net/~eclectic/woodworki...lone/index.cfm) and he maintains that using 6" pipe with an adequately powered cyclone is critical in controlling very fine dust (~1 micron and less).

Had I found this site before buying my collector, I would have probably opted for a cyclone. Instead, I've got the Delta 50-850 1.5 hp single stage unit, and I use a Jet separator lid on a trashcan to separate chips before they hit the Delta unit. I've also got an American Fabric Filter oversized 1-micron top bag (36" wide, 48" high), and the standard plastic bottom bag. But while the pipe between the impeller and the bags is 6", the Y-connector for the machine attachments is 4".

Is it a waste of effort to run 6" main pipes only to throttle them down to 4" at the dust collector and/or the machines? I realize that my demands on the system aren't too high, and each machine gets enough suction, but the point made on the site above is that larger main pipes, as long as they're supported by the DC and the machines, will help better collect the very fine dust (any my apologies if I misread his site).

If that's a waste of time, can I replace the Y-connector on my 50-850 with one from a larger unit in order to run 6" or 5" main pipes? I'll only be running one machine at a time, and will use blast gates, so I won't be tasking the system with long or convoluted pipe runs. It would be fairly easy to modify the port on my X5 Unisaw, and I am in the process of building better collection for my Hitachi 10" slider and the old RAS, as well as the new (Nahm-style) router table. The Delta 22-580 planer has a relatively non-negotiable 4" port, and the X5 jointer (I think) has a plastic 4" adapter plate that could be modified.

I'd hate to have to use 4" pipe, only to have to replace it all when I upgrade to a cyclone in the future.

Thanks to all for your help! BTW, after getting the feedback I did on my jigsaw question, I've ordered a Festool barrel handle model from Bob Marino, and I'm looking forward (with minor financial trepidation) to getting inexorably drawn into the Festool universe.

Thanks-
Bill Karow
Windham, ME

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Originally Posted by Bill Karow

and he maintains that using 6" pipe with an adequately powered cyclone is critical in controlling very fine dust (~1 micron and less).

Thanks-
Bill Karow
Windham, ME

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Bill,

Going from 6" pipe to 4" pipe will KILL your CFM air flow. When installing mine, we tested that with a Dwyer guage. 6" at 75' away with 6 bends in the piping was over 1048 CFM......dropping the end connection to 4" and the CFM was down under 700 CFM......Of course this is for a 5HP Cyclone setup (Bill's Design). What you need is 6" pipe and a 13" impeller.

I'm not venturing into the dust collection any further as it has a tendency to create "heated discussions". All I know if what works and works VERY WELL..!!!!!

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Originally Posted by Dennis Peacock

I'm not venturing into the dust collection any further as it has a tendency to create "heated discussions". All I know if what works and works VERY WELL..!!!!!

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Understood, and thanks for the reply.

Let me ask my question a different way. Given I have the Delta single-stage unit described above, is it worth trying to use larger main pipe runs? (Would that buy me noticeable performance improvement with my 1.5 HP non-cyclone unit?) I currently wheel the DC to each machine and use 4" flex hose, but I am trying to plan for "permanent" pipe runs.

If the DC itself is going to be my bottleneck for single machine use, I'll just use 4" pipe runs now and reconfigure when I upgrade to a beefy cyclone in a couple of years. If not, I can probably modify the DC and my machine's ports to get to at least 5" runs, maybe 6". Since this DC is to be used one machine at a time, 4" may be adequate. But if I can use bigger pipe now, it'll lower my costs when I upgrade.

Bill,

Is the wye on the DC intake removeable? If so most of these type units have a 6" connection already in place that the 2 X 4 wye just attaches to.

Yes, changing to the 6" will make an incredible difference in the system. The machine hoods really need to be increased to take full advantage of the larger pipe. This in not an expensive or complicated thing to do. I have used readily available HVAC fittings and register boot to do this in my shop. I have lots of pics and such in my "Shop Tour" and Dennis' system and a few others are in the "Buddy's Shops" section of my site if you would like to take a look.

The chip seperator is a bit of a problem. I don't think reducing the 6" to 4" into and out of the seperator lid will work very well. I have no direct experience with this situation, but have read that making 6" inlet and out for the seperator moves too much air and the seperator does little good. Perhaps someone with some personal knowledge of that can comment.

Terry

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Originally Posted by Terry Hatfield

The chip seperator is a bit of a problem. I don't think reducing the 6" to 4" into and out of the seperator lid will work very well.

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I think I can move it in-line right next to the planer and/or jointer (my main chip culprits). Hook the 4" flex hose out of the separator into the 6" main pipes. I'd get better flow at the TS and other machines, and have pipes in place I could reuse with a future cyclone system. Sounds like a plan!

Now I need to find a replacement Y-connector for the side of the DC's fan that has 6" pipes...

Thanks for the reply-
Bill

Bill,

As you've already heard, the 6" is the way to go. I have a 2 hp dust collector (bought from TWC at the woodworking show last year) with a 12" impeller that I hooked up to 6" PVC. It came with the 4" wye like many models do. Removing the wye leaves a ~5" connection. I wanted to hook directly to 6" PVC from the collector, so I made a new plate/cover out of 1/2" MDF and attached a 6" HVAC "take-off" (I think that's what they're called?) to which the 6" PVC is attached. I just traced the original plate/cover, drilled holes, cut it out, cut out a hole for the take-off, attached it, applied weather stripping to form a seal and attached the 1/2" MDF plate.

I was concerned that the 6" inlet to the collector might be more air than the 2 hp motor could handle without burning up the motor. It is 110/220 V, and I have it wired for 220 V. It's rated at 12 amps for 220 V. So, I connected an opened ended 10' of 6" PVC to the collector to see how many amps the motor was pulling. It was right at or just under 12 amps, and knowing that I would always have more restrictions than this test case, I was OK with it. After installing all of the 6" PVC ducting for the system, I checked it again, and don't have any problems with too many amps and thus burning up the motor.

I would suggest that you do some similar test. If the motor pulls too many amps, you could probably go ahead and install a 6" system and then intentionally build/design your blast gates to only partially open (e.g. rig them with a stop of some sort) to effectively restrict the amount of air being moved to keep the amps within a tolerable range. This would hopefully allow you to go ahead and install the 6" now and therefore not have to redo it when you upgrade the collector later on.

Mike

Bill,

I've got the same machine, and while I have not gone to 6" mains, I did remove the 4" restrictor ring. The inlet of the Delta 50-850 consists of a plasitc "Y" fitting that has two 4" inlets and a 6" outlet. This fits onto a restrictor plate that is pinched down to 4". Quite simply, this is a very poor design, and is probably the worst thing Delta could have done in designing the system.

What happens is that the air enters the "y" from either one or both 4" connectors, and momentarily expands in the 6" discharge. Is is then recompressed and forced through the 4" opening into the impellor. This momnetary expansion, then contractor, and then passage through what is essentially an orifice plate (in air handling terms), is a HUGE waste of engergy. What I did to correct this to remove the "y" fitting, then removed the metal restrictor plate. I replaced the restrictor plate with a round piece of 1/4" plywood with a 6 inch diamter hole cut in the center. I then screwed the "Y" fitting directly to the plywood. This eliminates the losses associated with the expansion,contraction, and orifice plate.

When these units first came out (Type 1), Delta did not have the 4" restrictor plate. They added it later with the Type 2 model as a cheap stop-gap fix to reportedly prevent people from burning up the motor by running the sytem without bags. At least that was what was reported on the net after the Type 2 unit was released when people began to realize how badly Delta botched this engineering modification. Essentially, by restricting the inlet to 4", they guaranteed that the motor could not over-load even if the unit was run without bags. For those of us who were not foolish enough to run the DC without bags, we got a nice sized performance hit thanks to the modification.

After the Type 2 unit came out, lot's of people began to modify the unit as I have described. Combining this modifiaction with the switch to 6" mains reportedly will net you a few hundred CFM at least.

IF you do nothing else, remove the restrictor plate as I have. It just makes good engineering sense. You're eliniating quite a bit of turbulence and pressure loss at the inlet to the blower. FWIW, after I made the mod, I checked the amp draw on the motor to verify that it wasn't being taxed. It wasn't even close to beibg taxed.

Good luck!
-Bryan

P.S. As a side note, I am an environmental engineer, and I think that Bill Pence's site generally has some very good information. However, cyclone systems are not the answer for everyone's needs. While cyclones have their rightful place in the dust collection world, so do DC's. For a myriad of reasons, I can't use a cyclone in my shop. I get by just fine with a combination of a good DC with 1 micron bags, an air cleaner, and respirators equiped with P-100 cartidges. I guess what I 'm trying to say is...don't trash your DC just yet.

Bill,

I had that same unit. I started off with 4" duct. I eventually decided to go the DE route and when I took down the old ducting, you would be amazed of how much fine dust and junk was caked throughout the system. I would advoid putting in 4". Now, you can take the wye off the front of the unit, I am not sure of the size left over but I would have to say its close to a 6" opening. Worse case, you can unscrew the entire cover off and build you a new one with a 6" flange. The impeller is small on that unit I think like 11" or 11.5", so you will be limited on maximum CFM anyways.

Or better yet, dump it and go for a cyclone. I got $200 out of my unit and spent it towards the cyclone.

The question is does your machine have enough umph to keep the velocity up in a 6" pipe? It might not. You can compromise and go with 5" mains, instead of 6", you would still experience a great improvement over 4" mains.

It's pretty amazing - only a few hours after asking my question I've already got some tremendous answers on how to test changes, what changes to make, and great information on my existing setup. Thanks very much for all the help!

Bill

I also have the same unit, with 2 4" leads into the 6" main. I believe it
was American Woodworker magazine(can we mention other mags here)
that had an article that used a single stage DC in a garage-sized shop.
The set-up was a single 6" pipe from the unit, dropping to a 5" line at
the first wye. This wye can be a 5-5-4 and blast gates for individual
machines.
I am thinking this may be the best set-up for a DC such as this, in a
one person hobby shop. Like others I would love to have a cyclone
but I want a jointer/planer first, and will make-do for now.
Check with AWW for a back issue for more details.

I thought that I might pipe in on all this cyclone stuff. I am a mechanical engineer with a large consumer products/paper company. I am purchasing fans, bag houses (very large dust collectors), etc. all the time. When designing a system there are three important factors: 1) Volume - CFM (cubic feet of air per minute) - I won't get into specifics here but there is ACFM and SCFM (actual CFM and Standard CFM); 2) STATIC PRESSURE; and 3) Velocity.

Why is each important -

1) VOLUME - this will determine how much air can be transported (i.e. how many machines and how large of machines can be running at the same time). The larger or greater number of machines running - the more CFM is needed! It's that simple.

2) STATIC PRESSURE - this will determine how long of pipe runs you can have, what size of pipe, and how many elbows. Remember, length, size and turns all affect pressure. The longer the pipe - more pressure drop. Every bend is a pressure drop. The faster the air has to move in the pipe (i.e. pipe size) the greater the pressure drop. If the pressure drop in the system is too great for the fan, nothing will get to the filter.

3) VELOCITY - This goes hand in hand with VOLUME and PIPE SIZE. The vedlocity of the air has to be sufficient enough in order to carry the number of particles and the particle size. The large the particle, the more Velocity is required.

Therefore, when designing a dus removoal system, all three factors need to be considered when buying the fan. You can contact me personally if you have questions.

Arvin,

Have you had some time to read Bill Pentz's site? It is in Bill's initial post that started this thread--curious about your experienced thoughts on the content.

I agree with Bill 100% - you MUST collect the dust as it is generated. That is why CFM, duct size and Static pressure is the needed information in order to adequately design the system.

The easy answer is to put in a 5000 hp vacuum with about 100" of static pressure - that will be enough to suck the blue off your jeans but that's not realistic. Design the system that you need and then add a safety factor in. I typically add 10-15%.