Wye Not?

[Bruce Seidner]

As I read and think about moving dust around I found this interesting contraption. I know that gentle bends have less of a CFM penalty than right angles. But as anyone pricing 6" wyes knows this gets costly fast. I have explored what it would take to make my own wyes and Pentz refers to a number of DIY solutions.

But what do others think of this junction box blast gate unit?

There is the introduction of more volume in the pipe line, but does it address the dynamics that make T-joints and right angles so problematic. I don't know what to think of it. [IMG]file:///Users/bseidner/Library/Caches/TemporaryItems/moz-screenshot-1.png[/IMG]

[John Lanciani]

Bruce,

I've got something on the same idea only larger. All of my large machines are in a central group with my dust collection dropping in the middle. There are seven 4" and two 2" blast gates on my manifold. It's not the perfect solution, but it solves more problems than it creates.

John

[Mitchell Andrus]

Bruce,

I've got something on the same idea only larger. All of my large machines are in a central group with my dust collection dropping in the middle. There are seven 4" and two 2" blast gates on my manifold. It's not the perfect solution, but it solves more problems than it creates.

John

Wowie-Zowie. This looks like something from a Jacques Cousteau documentary.
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For the young-uns out there... Google it.
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[Bruce Seidner]

Bruce,
It's not the perfect solution, but it solves more problems than it creates.

John

I think that is elegant, but then I am not an engineer. I have several machines in three work groups. Using 3 wyes to distribute to the work groups makes sense but for machines that are essentially side by side this sort of manifold looks great. What are you loosing by not having 6 wye connectors going off a branch down to 6 machines and by using this manifold?

What are the issues and compromises?

[Greg Portland]

Bruce, I like John's solution vs the picture in your post. The reason being is that John's solution has a very small bend for each drop's path. The solution you show has a very sharp 90 degree bend. If you want a 3:1 blast gate wye I would build the item in your 1st post but make it in a triangle shape (main duct on bottom, 3 intakes + gates on top). If you really want to get fancy you could include some internal vanes after the blast gates (in the body of the triangle)... this would help reduce turbulence & improve performance.

[Bruce Seidner]

I too am impressed with this manifold. It maintains the low angle of a wye and the addition of simple vanes make sense relative to the potential interactions when more than one gate is open. Though it is likely a true tempest in a teapot.

This makes sense for machines clustered like this. My guess is that there might be some loss of CFM with more than one gate open in the manifold compared to more than one gate open on a trunk with separate wye's and pipes to separate machines. But I have but two legs and two arms and have trouble thinking of a scenario where I would have a table saw and jointer going at the same time.

This looks like a winner to me. It also addresses the issue of two lines to a single machine like the top and bottom of a table saw or the mess that a miter saw spews and where both a hood/surround and feed off the blade are required if you don't want to feel like you are in Desert Storm.

[Prashun Patel]

Holy Clam and Cuttlefish! It's Doctor Octopus!

That, Sir, is a shameless gloat pic of your bandsaw and jointer.

[John Lanciani]

Bruce,

The biggest functional problem is with a small percentage of the heavier chips settling in the manifold depending on which ports I'm using. I figure that it's due to the airstream slowing down due to the cross sectional area being rather large. I'm sure that there is a small static pressure penalty but it can't be any worse than if I had all of the wyes and bends instead.

Operationally, the biggest pain is having to walk around and reach over machines to open and close the various gates. I'm toying with the idea of rebuilding it using eco-gates to open and close the ports as needed.

And yes Shawn, it was a small drive-by; it's a MM-20 bandsaw and a Rojek MSP-415(16") J/P with a Byrd head. The dust collector is a V-3000H. You should see the rest of the shop...

John

[Prashun Patel]

And yes Shawn, it was a small drive-by; it's a MM-20 bandsaw and a Rojek MSP-415(16") J/P with a Byrd head. The dust collector is a V-3000H. You should see the rest of the shop...

Yeah, well at least yr still hayseed enough to keep rockin' the ni-cad 14v Makita drill, I see.

[Kent A Bathurst]

Wowie-Zowie. This looks like something from a Jacques Cousteau documentary..

Nope.

Maybe from the first Alien movie, but more likely from the film Brazil. Just need DeNiro swinging in on a rope to fix it.


Me likey. Very clever way to create tool-holder space.

[Bruce Seidner]

Bruce,

Operationally, the biggest pain is having to walk around and reach over machines to open and close the various gates.

John

In keeping with the Brazil theme, could you arrange handles and levers to accomplish this? For instance if there is a blast gate close to the floor on a table saw it is not hard to rig a lever higher up that has a rod on the end that is attaches to the gate. The arc of the lever makes it a small travel and you don't have to get down on your hands and knees to operate the gate. Of course why people put the gate down there in the first place is a bit of a mystery.

I am going to make some of these puppies in two and four gate variants. I will include internal vanes and a sliding bottom that will cinch up and seal with the machine on and relax and slide open easily to empty it when the machine is off.

They have a bit of a pagoda style to them so maybe hand rubbed red lacquer?

[John Coloccia]

Wowie-Zowie. This looks like something from a Jacques Cousteau documentary.
.

I don't see what the Pink Panther has anything to do with this.

[Paul Wunder]

Bruce,

it looks to me as you have one input from a flex line exiting to one of three flex line presumably to a choice of three machines. You also have a lot of restrictions from the 90 degree bends in the "junction box"

Have you tried using Bill Pentz's "Static Calculator" on his web site?

I do not think there is an off the top answer.

You need to consider the cfm needed at each machine and start at the beginning (at the collector) and calculate the starting cfm, the static pressure loss caused by each length of ductwork, each bend, each type and size of ductwork that you are using (pvc,flex, metal; 4",5"6").You also need to consider the "loss" at each "hood" at the machine. When your calculations are done using your real world situation, you will have your answer. it will either work for you or not.

For your calculations I would not consider your junction box as a "90 degree bend". I would add a significant factor for "turbulence". Bill Pentz talks of the effect of turbulence on his website.

We all want to be cost effective, but since we invest a lot of time and up front money to get results, I would suggest "the long view" and build what will work.

Paul

[Mitchell Andrus]

Nope.

but more likely from the film Brazil. Just need DeNiro swinging in on a rope to fix it.

YES! I forgot about that one.
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[Joe A Faulkner]

Bruce,

And yes Shawn, it was a small drive-by; it's a MM-20 bandsaw and a Rojek MSP-415(16") J/P with a Byrd head. The dust collector is a V-3000H. You should see the rest of the shop...

John

John, I can't speak for Shawn, but I'd love to see the rest of the shop. How about a tour?