I need my maths checked - Router Forums
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post #1 of 21 (permalink) Old 07-09-2016, 03:27 AM Thread Starter
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Default I need my maths checked

I have a dust deputy clone cyclone. its got 50 mm inlet and outlet. Thats not big enough for my 63mm ductwork.

so, if I multiply the 50 x 24% i get 62, yes?

Therefore, if i make my own larger cyclone and just multiply every measurement by 24%, it will end up in perfect scale, yes?
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post #2 of 21 (permalink) Old 07-09-2016, 06:30 AM
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Sounds good. I just got a Dust Deputy a few days ago, and wrapped the inlet with enough painter's tape to get a good friction fit. Masking tape or duct tape should work too. It didn't take much tape at all--might be worth trying before building your own.

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post #3 of 21 (permalink) Old 07-09-2016, 06:37 AM Thread Starter
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I've had mine for 18 months, its a brilliant device. I also used tape to pack the joints.
But I've improved all of my ductwork and now this is the smallest item in the line, causing a big restricyion of flow. To but the next size up is a stupid amount of money. So I'm going to make my own.
I've just worked out the size of the new improved one using 24% and I think I can go bigger again without losing anything.
So now I'm working on 50% larger.
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post #4 of 21 (permalink) Old 07-09-2016, 07:44 AM
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I'm sure it's just a typo but I think you mean multiply every measurement by 124%, No?
Beyond that, I'm afraid I'll be of no help. I suspect there's an engineer in the group who can provide you with the right answer.
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post #5 of 21 (permalink) Old 07-09-2016, 07:46 AM
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I have a dust deputy clone cyclone. its got 50 mm inlet and outlet. Thats not big enough for my 63mm ductwork.

so, if I multiply the 50 x 24% i get 62, yes?

Therefore, if i make my own larger cyclone and just multiply every measurement by 24%, it will end up in perfect scale, yes?
Just guessing, but wouldn't the size "ratio" be based on the relative cross-sectional area of the inlet/outlets?
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post #6 of 21 (permalink) Old 07-09-2016, 07:49 AM Thread Starter
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woodchip, yes, increase the size 24% over original. Now working on 50% larger. looks do able.

Tom, dont confuse me (its far too easy) i assumed by increasing all measurements the same percentage would keep the flow going.
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post #7 of 21 (permalink) Old 07-09-2016, 10:35 AM
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Quote:
Originally Posted by sunnybob View Post
I have a dust deputy clone cyclone. its got 50 mm inlet and outlet. Thats not big enough for my 63mm ductwork.

so, if I multiply the 50 x 24% i get 62, yes?

Therefore, if i make my own larger cyclone and just multiply every measurement by 24%, it will end up in perfect scale, yes?
This is true for the linear dimensions, but will not hold true for the area of the circular openings that are a square function.
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post #8 of 21 (permalink) Old 07-09-2016, 10:50 AM
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If you are planning on building your own, you should consider making a Thien separator. They're a lot easier to build, and give equivalent or near equivalent performance to larger cyclones.
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post #9 of 21 (permalink) Old 07-09-2016, 11:51 AM Thread Starter
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I've looked closely at a thien. i have to admit i find it lacking. Every video I've watched says it needs tweeking and adjusting. And to be honest, That seperator looks a lot more complicated than a cyclone.
i'm happy with the vacuum power, got no desire to start all over again with motors and fan blades. My dust collection box seems O.K.
My only problem is I have a 50mm cyclone in the middle of a 63 piping system. Its an obvious restriction that I think I can improve on.
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post #10 of 21 (permalink) Old 07-09-2016, 11:55 AM
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Before you go to all that trouble, have you actually tried a reducer to transition to the smaller Dust Deputy inlet/outlet?
Of course it won't be perfect, but how big is the inlet on your DC? (I'm guessing 63mm?)
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