8" Piping Resources and design

[JaredM]

I'm planning on buying the CV Max kit, without the Wynn filters. I just plan on sending the exhaust outside as I own a few acres and there is no one around that will be affected. I noticed on the drawing and specs page that, for the CV Max, 8" pipe should be used for optimum CFM. Has anyone set this up and have any tips about working with this size?

I've come across this site that claims to sell 8" PVC for $8.99 per foot. Has anyone bought from them, or have better recommendations? http://www.usplastic.com/catalog/ite...5745&catid=727

Thanks for your help!

[Aegwyn11]

$9/ft? Thats $90/10 ft stick. You might as well get Nordfab for that. I suggest looking for either a local metal shop that can do spiral pipe or look for a local plumbing supply house (the kind that sells BIG PVC pipes...not the HD or Lowes)...they'll be a lot more likely to have the thinwall PVC stuff if you really want to use PVC.

[Jim O'Dell]

If the thin wall is available in 8" I'd bet it would be expensive. I second the idea of finding a local Mom and Pop shop that does spiral ducting. Some have found it in 6" for about the price of 6" PVC. Jim.

[JaredM]

LOL, thanks for the replies. I don't know what would be a good price for 8" piping. I was looking for 2729 PVC as recommended by Bill Pentz. I'll check around and see what i can get spiral for. I'll also try calling around to the plumbing supply stores like you suggested.

So can you tell me what would be a decent price you would expect for spiral or PVC?

Thanks again!

[Jim O'Dell]

In 6", the norm is about 18-20 for a 10' piece. I got my first two at 18.60 each, then the next 3 were at 9 something each!! Ask a plumber or someone that installs drainage where they go buy their pipe. That will be the big yard that has a bigger selection. Jim.

Oh, and where are you? Knowing your location may help us recommend a local place for you.

[JaredM]

Hey, yeah...I'm way off the mark I live in the Seattle area. Any resource you can give would be great.

Noticed James put some new options on the site. So, initially i was just planning on putting a 8" dia. pipe down the middle of my shop and peel off to my tools, but upon reading some of the product description, "It has an 8" inlet and requires 8" ducting split into two 6" lines to fully utilize it's capacity."

So...whats most efficient? Having 2 - 6" lines from the cyclone would be great, but I just want to make sure I'm doing it right. I have a stand-alone 30'x40' shop with 10' ceiling. So now what I'm thinking is putting the cyclone in a corner, run the 8"dia. section along the 30' wall to about the middle of the shop. Split the 8" into 2 - 6" sections. Then taking one pipe along the back wall, while the other through the middle of my shop. Does this sound like a good plan, or am I introducing problems in accordance to Bill's research.

I know I'm probably going overkill and could just go with the standard 15" impeller model; but there's a part of me that says...it's a 5 hp motor! Use it to full potential! The Tim Allen phrase comes to mind..."y'know what this needs? More Power!"

[CribbageGuy]

Exactly the same issue here. Need two machines running, sometimes three at a time. Tempted to do it properly with the Max, yet confused about the 8" and 6" situation.

Thinking of doing an 8" main across to the two biggest machines with 6" drops. Then taking a 6" main just before the the first 6" drop over to the other stations. Its hard to picture an 8" to 2x6" transition. So maybe by putting the 6" leg close to the cyclone, I can avoid the transition at all.



I guess 8" has an area of 48 sq in and 6" only 28, almost half.
So running 8" everywhere would leave a too low duct speed, hence the need for two smaller 6" pipes?

As to finding the pipe, who knows?

[bababrown]

I think you will need to figure out which two machines you want to run simultaneously. Or better, what combinations of two machines you want to run simultaneously. You've got it right, you need two open 6" pipes to feed an 8" pipe of any significant length. Otherwise you'll slow the flow in the big pipe. And of course you need an 8" pipe to feed any two open 6" pipes.
bababrown

[CribbageGuy]

"I think you will need to figure out which two machines you want to run simultaneously"

Sorry. Those are the two at the top of the diagram on the 8" main with 6" drops. I figure those are working quite often, the others just occasionally.

Thanks for the help!

One question I have is what happens when the 16" impeller is running and one or even no gates are open? Should I have an "open pipe end" with a blast gate somewhere to just keep the air flowing and the air exchanged?

[JaredM]

Originally Posted by CribbageGuy

"I think you will need to figure out which two machines you want to run simultaneously"

Sorry. Those are the two at the top of the diagram on the 8" main with 6" drops. I figure those are working quite often, the others just occasionally.

Thanks for the help!

One question I have is what happens when the 16" impeller is running and one or even no gates are open? Should I have an "open pipe end" with a blast gate somewhere to just keep the air flowing and the air exchanged?

I claim very little understanding of anything so please correct me if I'm wrong. The ideal solution would have 8" duct go to everything. Since that isn't feasible, you can open 2 x 6" ports, that way you have the same amount of air traveling through the pipe as you would with 8".

If you have 1 closed, your reducing your CFM considerably. I would have to check Bill's page to look at the math to give you definite numbers. So that might clear up some things. So you want to constantly keep the same area as an 8" pipe for maximum CFM. Below shows some quick numbers for keeping this in mind.

8" diameter pipe area = 50.24
6" diameter pipe area = 28.26
4" diameter pipe area = 12.56
3" diameter pipe area = 7.065
2" diameter pipe area = 3.14

If your concern is about safety, if your using pvc for the pipe, i wouldn't worry about the pipe collapsing, if your running with 0 gates open, you'll probably just shorten the life of your motor.

So that might clear up some things. Again, I could be blowing smoke, so someone please correct me if I'm wrong.