Thread: Ultimate DIY Separator / Extractor

In the other column it says

B minimum Mean Outside Dia (mm)

= 250, this would suggest the pipe dimensions are for 250mm pipe not 200mm.

Wouldn't make sense for the ID (225) to be bigger than the OD (if 200mm pipe)

Circumference in mm (2 x Pi x r)
150mm = 471, 146mm = 458, 100mm = 314, 96mm = 301, 90mm = 282, 86mm =270

Square mm in Area (Pi x r x r)
150mm = 17662, 146mm = 16733, 100mm = 7850, 96mm = 7234, 90mm = 6358, 86mm = 5805

Inner area of outer pipe, subtract outer area of inner pipe: 16733 – 7850 = 8883
4 * 8883 = 35532 sq mm (outer pipe) vs 4 * 7234 = 28936 sq mm (inner pipe) vs 1 x 17662 x sq mm (exit pipe)

Factoring in some flow restrictions, outer pipes have two surface areas for drag (inside of outer pipe and outside of inner pipe) with a smaller cross section (effective smaller diameter (146 – 100) / 2 = 23mm), whereas the inner pipes have only one surface area (inside of inner pipe) and a larger cross sectional area (1 * 86mm).

200mm (196) = 30156 sq mm, meaning a 200mm exit pipe could almost be used for the 4 * 150/100 mm pipe design as well, IF you had a 200mm DC inlet.

Using 4 * 150mm pipes instead of 5 or 6 means the pipes can be grouped closer to the centre of the cyclone, allowing for possibly even less aggressive angles into the exit pipe.

All the 150 mm DVW pipe I have worked wit is 154 mm ID!

Originally Posted by HeadScratcher

In the other column it says

B minimum Mean Outside Dia (mm)

= 250, this would suggest the pipe dimensions are for 250mm pipe not 200mm.

Wouldn't make sense for the ID (225) to be bigger than the OD (if 200mm pipe)

I don't follow. There is no pipe size between 150mm and 250mm that I can find, it would make my life a lot simpler if it there was. PVC pipe sizes are just weird as Bob so rightly points out with the ID of 150mm being greater than 154, the OD of that is 160, let me know when you figure it because I can't. out

Found this... PVC pipe sizes

The sizes may not be exact but the inside and outside numbers seem to line up when you add the wall thickness.

150
SN4
160.3
4
152

150
SN8
160.3
4.8
150

This shows the OD as 160mm but thats fine.

100
SN6
110.2
3
104

100
SN10
110.2
3.5
103

100mm isn't 100 either...

Near as I can work out, if 150mm pipe is actually 152mm, then it probably exactly 6 inches. 103mm would be exactly 4 inches, so these are really imperial sizes that have been metricised.

Peter quite possibly that is the case... They probably didn't retool, they just called it the nearest metric thing. Also some pipes seem to measure ID where others measure OD.

Quick update... Bought two lengths of DWV pipe today

1 x 198cm (just shy of 2 meters) 160mm OD / 152mm ID
1 x 100cm 110mm OD / 103 ID

I think the difference between DVM and stormwater is one is measured ID the other OD. As 90mm stormwater is 90mm OD.

4 x 30 degree 100mm (110mm OD female end, even larger male end) male / female angle fittings.

All up todays bits were $50 ($49.95) plus $80 for the two 700mm x 700mm x 6mm clear sheets, total so far $130.

So the project begins...

Was wondering if there is some kind of official ratio that it needs to be built to. I was thinking 60/40, 60% Tapered section / 40% body section and the inside tube being 3/4 of the body sections.

So what would that look like in numbers?

Well I was thinking if both taper and body were 400mm (40cms) combined per cyclone, times by 4 that would be 160cm of the available 198cm (minus cuts, squaring up etc.)
With the rest being used for the outlet and inlet tubes.

60% of 400mm is 240mm for the taper and 160mm for the body.

.75 or 3/4 of body is 120mm for the inside pipe plus the 30 degree angle which sits on top.

What do you think do the numbers sound right for the size of the pipes?

Edit:

Should probably mention I won't be cutting the 400mm tube, I will simply put a taper on the inside of the tube.

Now that I have some accurate measurements of pipe sizes I looked to see if I could get away with 3 cyclones instead of 4.

Maths below.

3.14 x 76 x 76 (outer tube ID) = 18136
3.14 x 55 x 55 (inner tube OD) = 9498
18136 - 9498 (outer tube area) = 8638 x 3 = 25914
3.14 x 51.5 x 51.5 (inner tube area) = 8328 x 3 = 24984
3.14 x 76 x 76 (outlet tube ID) = 1 x 18136

With restrictions is possibly just doable. The big benefit to 3, is the tubes are much closer in the middle meaning the angle piece overlaps the centre pipe better, meaning less extension required to the angle pieces.

Unfortunately the male part isn't long enough to go right into the centre section and will need extending. The more overlap the better.

Originally Posted by petersemple

Near as I can work out, if 150mm pipe is actually 152mm, then it probably exactly 6 inches. 103mm would be exactly 4 inches, so these are really imperial sizes that have been metricised.

Originally Posted by HeadScratcher

Peter quite possibly that is the case... They probably didn't retool, they just called it the nearest metric thing. Also some pipes seem to measure ID where others measure OD.

Why alter machinery that most likely been designed and built in the USA or UK where they still use imperial measurements.

Except 4" is 101.6mm not 103... not sure they are making it either metric or imperial, looking at those weird pipe sizes I swear they have come up with their own unit of measure

Just need to build myself a hole cutter and I can begin work on the cyclone. Might start a build thread once I'm ready to start.

Ready to see this rocket take off!

Just trying to work out how to accurately cut all these tubes with square ends and at the right length.
Currently putting together a rough adjustable circle cutter for this job. The plan is to use some scrap MDF and cut 100mm / 150mm holes in it * 2, and mount them to the bench.
Hopefully when I put the pipe through them with a stopper it will hold it tightly in place, with careful rotation and holding the 4” disk grinder with cutting disk square against an edge cut some neat edges.
That’s the plan, will have to see how it goes… (can’t be any worse than the job the guy at the store did with the hand saw)