Backyard Aquaponics
A place to discuss aquaponics

Actually, I would beg to differ..
They both work the exact same way by slowing the flow and allowing the solids to settle..
The RFF (classic) by direct food down and then broadening the flow and reversing the direction..
The SWIRL, by directing the inflow around the walls and thus slowing the flow and because the swirl keeps the solids against the wall, it allows the clear water to return up the centre..
Slowing starts immediately the water enters the device

I have often thought the typical design of a classic RFF, is slightly questionable, in that they use a small and vertical tube to force the inflow downwards, and within the tube, water velocity remains the same. - ie no slowing..
Slowing only starts at the bottom of the tube... for this reason, I would start with a coned central tube, so that slowing starts immediately.

What I want to try, is a combination, where you have a classic swirl, but use a medium sized central tube., to shield the outflow at the top centre, from the swirling solids..
I have not tried it, because there is so little solids exiting my device, that I wonder if the effort is worth it..

The water cooler bottle IS a great shape for these filters, but is surely seriously limited to VERY low flow rates and thus extra small systems.. my device uses a 60L Drum.. I only wish I could reliably convert the base to cone shaped..
I did manage to dome the base out, by using a stainless dish and weights INSIDE, and heated from the outside, allowing the base to slump slightly.. ( and I am NOT suggesting that my device is special.. it just works well..)

Coaxial plumbing is easy, using T pieces and reducers..


TITUS.. I hear your comments about studying art etc, and thus assume you are saying that your sketch is tachnically correct.. if so, I repeat my comments as to where I would have the inflow level, .. ie. Closer to the top, to allow more settling depth.. and I respectfully suggest that as you have shown the filter, it is a basic SWIRL, and not a combo.. IMHO

I understand that you want to use a water cooler bottle.. those. FIFTEEN Ltr. PET bottle with handles..
My thinking... the handle molding will disrupt the flow, and thus the inflow should the as close to the top as possible.. ie where the shape is still round..
.

How about just sticking about 30l of bottle caps in your RFF?

Edit
and run two in parallel.

Ah. Nothing more embarrassing than a joke which doesn't travel. Or worse is not funny.
My fault!
To misquote Stuart, Sometimes my need to tell a story out weighs the need for accuracy.
The water cooler bottles I use are 25 L and yes the handle does get in the way. Handy though for securing.

I must say that I have NO IDEA what you are talking about, and respectfully suggest that there may be commercial reasons for such strong support for RFF..
They are so close to the same design, there is no way you can suggest a significant difference, and the only difference is HOW the inlet water is injected..
Don't get me wrong.. RFF's are likely a great device, but it's a bit rich saying the Swirls don't work, and use MORE ENERGY and are hard to configure..
My one worked first time.. and removes 99% of solids.. and cost precious little to build..





and especially when it inferred a good appreciation of perspective..

all good..

Back to my device - the one thing that is lacking, is the lack of a conical base, resulting in the need to flush the solids with a deal more water (20L), and the need for a device ( Picnic Plate on legs ) to act as a vacuum head, but hay, it cost about fourty bucks to build using standard Bunnings fittings..

BTW - one "Problem" with my device is that naughty small fish that get under the SLO shield, end up in the ST, by following the "Flow".. ie.. there is near nothing to block.. as ALL pipes are the same size 50mm.. and the water height in the whole system , is determined by the height of the final outflow nozzle..
..
.

I don't think that I have ever seen that larger size bottle.. I suspect they exceed the stupid "RULES" of occupational health as to acceptable weight for lifting..

Titus - Your system is obviously a micro system so go with the swirl, using the coaxial tube for muck-drain and outflow, and have the inflow at the top, just above the outflow stand pipe.



Paint to make the plastic last under UV, and try a T on the IN side and a 90deg elbow on the other end..
Each "Nozzle" points in the same flow direction and slightly down and as close to the walls as possible..

My only concern would be the size of the outflow/overflow, which is likely limited by your desire to fit it all in the small neck of a standard bottle, and then as a coaxial device..

I would consider going through the side-wall with the outflow pipe and make it as big as practical, to remove the possibility of the inflow exceeding the outflow.. BUT... only you know just what flow rate you need, but, did I read 250Gal FT, so the flow should be at least 250G/H
..
.

Not being pickie, but it is interesting that they depict the complex design of the RFF and not even a sketch of the SWIRL..

Me smells a stitch up..

AND PS - TITUS.. I just visited your system thread...


Surely you are NOT talking about using this water bottle filter on this system???
..
.

"250Gal FT, so the flow should be at least 250G/H" serious? Crud, I've got a 2500 gallon FT. I didn't know it all went through the filter in an hour. Or is this more for RAS?

,Page 52 figure 2 is the Swirl Separator BuiDoi. Page 53 figure 3 is the Radial Flow Filter.

Yes the designs are very similar

On your design, how do you clean the area in the cutaway on the bottom away from the solids drain? It looks like the solids drain is closed off and that shoulder area would collect solids that wouldn't flow out and would decompose anaerobically.

Well I do have an idea of what you are talking about and your suggestion is ludicrous as you well know. Since we are talking about HOME MADE devices what possible commercial interest could I have?

You really need to apologise for your suggestion that was totally disrespectful.


This just shows that you don't know what you are talking about.


I never said swirls don't work, I said they don't work as well as a RFF and they do require a higher hydraulic head which does require more energy.


Well like I said IF you can do this that is very impressive because it is close to double the effectiveness of the claims made about commercial units.

Brian, I can only assume that the entire flow from the SLO goes through.. What is the alternative.. say 50%..

so if 50% goes through the filter them 50% of the solids will surely bypass the filter,
and I thought the whole idea was to capture ALL the solids..
and then IF we accept the "Rule-Of-Thumb" that you should have 100% water change per hour in a FT, then YES, that must mean that 250G/Hr must flow through the filter..
but so what.. My FT is about 950L and I am pumping at about 2500L/H but through the Swimming Pool Canister Filter plus the Bio-Filter to the FT.
I assume there would be little back pressure from the Bio-Filter (tube), but the canister filter would.. as would the approx. 1/2M lift
so perhaps there may be 2000L/H ( I do wish that I had a Doppler flow meter)


OK - fair cop.. but I thought that this was all about backyard systems and DIY stuff, and not buying the best commercial products.. and so claiming that commercial RFF are far better, is still a bit rich..

I do now see the two sketches as being different - apologies
I thought the swirl was a sub part of the RFF - as you say - similar..
But how can you compare such a seriously complex construction device to a humble Olive Barrel filter

I have NO DOUBT that the efficiency of any device will be controlled by it's size and water velocity..


Not understood Some of the solids get swirled under the plate and sit in the depression. and a lot sits around the edge..


The solids drain works EXACTLY like a FT SLO..
Like Titus, I did not go to art school and have better thing for my time than accurate drawings..

So I have a plate standing above the base.. separated by stainless bolts as legs.

The solids drain pipe inserts vertically through the plate and into the void between the plate and the re-moulded base..

When the clean tap is turned on, water gets violently sucked from under the plate, vacuuming the solids from UNDER the plate, the plate rim, and then from the barrel edge..
If the muck has set, outside the plate a simple poke with a stick sees it disappear under the plate

It works, so there is no argument that it does not, but as I declared, it is water wasteful, and need about a 20L flush to move most of the solids..

I would like to make a CONE to fit into the device, to sit tight in the bottom, to replicate what your referenced units look like, and then suck from the ??apex?? of the cone - that's one of those GUNNA jobs, but whilst I can remove near all the muck but with 20L of water, it is not high priority, when the muck goes into the MT and the bulk water to the soil gardens or back to the ST..

Don't blame me if this CHEAP DIY does remove so much, but I can assure you it DOES, and thus I can't see how a RFF can be any better ( and yet again - AT MY FLOW RATES )

ANYONE is welcome to see for themselves.. Heaps in the first swirl, next to nothing in the second, and absolutely nothing in the sump..
..
.

Well it all goes through the media grow beds...

How do you think they will go one above the other.. assuming that is what we are looking at.. just thinking of shadowing..
..
.

once the season changes and we're not seeing super hot days I'll roll the reed cloth down. Those beds will get direct morning sun until Noon, well at least that is how I planned this.

is their any math to determine the size of the RFF ?

ie) if I was flowing 30kL through it an hr ... inlet size would be around 2" / 60mm

Yes there is but you size a RFF based on the flow to determine the surface area of the water in the RFF or in other words the size of the container you use to build one.

Sizing the inlets and outlets is more about reducing friction losses through the rest of your system.