Backyard Aquaponics
A place to discuss aquaponics

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A wise person advised me..
"Don't get involved in discussions on FILTERS -You will never win, and the other one is always the best"

Well I am not that worried about being the BEST, but keen on Recycled Parts, and by using an old Fisher-Paykel (HDPE) outer tub, I seem to have made an efficient swirl filter.. and if it's CHEAP and works - then I am one happy camper..

I call it an "Inverse" Cone Filter, because we kinda know that the better swirl filters have a deep cone shaped bottom ( = EXPENSIVE ), so the solids will (hopefully) migrate to the base, ready for removal..

Mine is an Inverse Cone, because the base of the outer tub is raised in the center and falls to the outer wall, and then spirals down, to the recessed pump port, where solids collect..

This generally means that the solids that "Fall" down the wall, will fall into this descending helix channel and be swept into the pump well.. which it does.. ( Subject to the vagaries of turbulent flow )

I have played for a while and realised that theory and practice don't always go together, and that SOLIDS will collect in the calmest waters.. so my first attempt was a small failure because so much solids sat on the apex of the base - in the center..
Naturally, that was an easy fix.. All I had to do was to remove that apex, or make it disappear.. disappear by turning a mole-hill into a mountain, that moved the new apex almost to the top of the water column.. Simple fix - - an up-side-down flower pot

So the basic filtration system for my (Plant-Less) system... consists of..
ST > Bio-Ball MBBR > Tubular Bio-Filter of Bird-Netting and Bio Balls > FT thence
FT > Swirl Filter > ST

So that is what the finished product looks like..

First a clear warning.. the Outer-Tubs of the washing machines are not UV stabilised and left in the sun will quickly turn fragile, so plan on covering or painting WELL, in the very least..
( Paint - Rustoleum "Ultra Cover" seems to really stick to HDPE )


Slightly RAW tub.. Sprayed and entry hole drilled

So - CONSTRUCTION.. Part 1

What you will need:
Gas Blow Torch - OR - Electric Paint Stripper
Large Electric Drill
Hole Saws of normal size for plumbing (uniseals) PLUS 64mm (special)

First find the large size Fisher Paykel washer and strip it down.. you only need the OUTER TUB and the water pump..
1. Pull the top from the aggitator, and the large "RIM" from the outer-tub
2. Reach inside the aggitator and unscrew the plastic Wing Nut
3. Lift off the aggitator... and lift out the main wash tub
4. Remove the whole tub assembly from the case.
5. Turn tub over and using a suitable socket set, unscrew the plastic NUT in the center of the motor, raising the rotor and then remove it
6. Undo the 4 screws in the stator assembly, and remove all
7. Remove the remaining bits, such that you only have the Outer-Tub and Pump with drain hose
8. Remove the pump, retaining all bits (for re-assembly later)

Your first construction job is to remove the Aluminium Bearing Support Tube, which is molded into the base.
This is done with either a gas blow torch or a Hot air gun..

place the upside-down tub on (AIR) spacers and place a large bowl of cold water underneath to catch plastic melt..

You play the Torch/Gun into the tube from the base.
You just go around slowly in circles and at varying depths, heating and heating whilst avoiding damaging the outside plastic material.

After a time, the HDPE inside the tube will TURN CLEAR, melt and start flowing. It should completely drain away.

Now keep heating and you will see the plastic on the outside of the tube turning CLEAR..
Have an object like a small glass bottle ready.. One that wont go through the center hole.. (Coke Bottle) You can use this to do the final "Push" out..

So you see clear plastic, and you think you have heated well down the depth..
Use the bottle to see if the tube moves.. if it start to move then go for it and just press it down and out of the tub..

IF you have achieved this - the worst is over...
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.More Soon

Thats awesome that you managed to use a washing machine for that

my friend is a washing machine repairman. ill ask him if hes heard of HDPE outer bowls, i never have.

we use the cages (outside is bowl, inside is cage) he gets as firepits. they make primo barbecues.

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So now you have a bare tub with the Aluminium Support tube removed..

or - perhaps you haven't, because you were NOT told to remove the spin axle and wack out the bearings and top inside seal..

Best done from the outside/UpSide down, to remove the inner(s)

a LARGE screw driver or shaft.. shove through the bottom bearing and slide down the opposite wall until it stops (sitting on the inner bearing) - give it a bash
Now go to opposite side and give an equal bash.. repeat and the seal and the bearing will fall out
Now tip over and repeat from the inside, having supported the whole tub on blocks, and bash that other sucker out..

So NOW you do the melting thing, and remove the spin tube..

Now you need to think about PIPE dimensions..
At first I planned to use 40mm tube, but decided that 50 was a better choice.

My first thought was to use threaded 50mm fittings top and bottom and use the remaining cleared tube itself as pipe work..
I did that , sealing the two fittings in and eventually (as nothing sticks to HDPE) they leaked stupid idea..
(hint - whilst Gorilla Glue (etc) sticks like..IT to most things, it does seem to become porous and will often allow flow through.. I have had small leaks in the past but they sometimes block and seal via solids getting caught )

You will see in the assembled images, how there are those 50mm pipe fittings in the tub base..
They are now gone..

I scratched my heard wondering HOW I could enlarge that remaining hole of complex shape, so that a 50mm pipe could be stuck thru and sealed in ..
A Christmas-tree (stepper) drill would be great, but I doubt they make one the RIGHT size..

I went to my local trade supplier and finally chose the 64mm hole saw as the best choice for a clearance hole..
So how do you use a Hole Saw to enlarge an existing hole..

One way is to rebuild the "HOLE" by plugging with a shaped block of wood (probably the better choice).. and then mark the center and re-drill, knowing that once you have STARTED, the hole-saw will self center..



I did it the HARD way and used the next smaller hole-saw - one the just fitted inside the 64mm..
as a guide, and by shoving a dowel in the hole.. cut that dowel to the right length - which was JUST left the small saw, sitting above the base.. and then I used this to "Start" the 64mm saw, in the right place.. once started, it did not need any guidance..

I think that I would shape a wooden plug next time.. as it would cause LESS CHATTER and a neater hole
so now we drill straight through.. as straight and vertical as you can..
Not a precision job, but it worked and a short length of 50mm pressure pipe was "Wetted" with Gorilla Glue or any brand expanding ureathane foam glue, and slid into the "Wetted" hole and allowed to set..

This gives a semi- water tight path through the base which you can see, from the removed spin tube, is about 150mm deep..
Excess glue can be peeled off to clean it all up..
NOW - you need to make sure the ONLY point of leakage is sealed forever.. ie that where the stand-tube enters the inside of the tub..

Here I use a SCOTCH sealant -- Scotch-Seal 800 -- used for that purpose.. to seal water seals to HDPE and other tanks.. I suspect that Zinzer and other sealants could work..
( YES - that Scotch 800 is not food grade, but how much nastie stuff can come from a smear )

So now, you have a sealed pipe thru the tank base.. you can extend the stand-pipe to the desired height using a 50mm joiner and more pipe.. PLAN on having that initial stand pipe, just above the base... You can EASILY extend it but will find it hard to shorten
You can add a flare to the top with an adapter..

You can add a "Floaties" excluder by using a short length of 150mm tube and cap and the carefully fitting long stainless bolts to act as legs to hold this excluder above the inlet.. Drill a small hole in the top to prevent Auto-Siphon..


Now I admitted that the flat area was an issue and that much solid matter gathered there, so I found a suitable container - like a flower pot.. drilled a clearance hole so that it slid over the stand pipe and was wide enough at it's mouth to cover most of the base- up to where it dropped into the helix..

so as mentioned I used a flower pot like item which slipped over the stand-pipe, pressed to be floor, and a 50mm UniSeal pressed on to to secure it hard on the bottom..

Now I commented about how flows were unpredictable, and strangely you would still find pockets of muck where it should not be....

The most important thing was for the solids to STOP at the pump location.. this I found , could be aided by using short lengths of heavily drilled pressure pipe , at the pump site, to create eddies and the likes and suck the solids from the swirl.. It worked.. and if you find strange spots where muck gathers, then their little party can be ended with similar devices..

Now you are near to ready to start assemble of the whole thing.. You will refit the pump, later, but first remove the "Object" cover from INSIDE the bowl.. this stops buttons and bra-wires from getting to the pump.. Carefully drill a number of holes through the skirt, so that muck is sucked from all around.. refit the cover..

Now you can fit a short length of pipe thru the side entry hole and make a tube to raise the release to near the full height mark.. for this reason, I "FEEL" that it is best to enter from about the half way or lower, so the you can adjust UP to the correct height..


This was a Mk1 photo, using fittings top and bottom of the base and prior to drilling out and a continuous pipe used.. Today, that joint is obscured by the Mole-Hill Cover..

In three to five seconds, I can remove most all solids, and removing only about five Ltrs of water..
Now that is pretty efficient..

I will try to automate the process via time clock so that I KNOW that solids wont gather, and start breaking down, when we do go away..

PS - MOST modern top loaders use HDPE outer bowls..
I have detailed the Fisher-Paykel machine, as MANY are now appearing at tips and on road-side junk collections.
Whether, other brands have a better descending helix, I can't comment, but again it the depth of that helix that determines how well the principle will work..
PPS

and a final point on draining.. I slapped up this inelegant means of pumping to a below bucket..
The upward going pipe is just an open breather.. preventing Auto-Siphoning, and allowing for surge from the pump..

I allow the muck-bucket to stand for a day.. scoop the floaties off.. drain the clearer fluid and leave the settled muck for the next drain and clear, and eventually, dump it in the MT..
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not no more... Almost all tubs are plastic.. the only exception being the big Americans, which still use enameled steel..
Even 20 years ago, hoovers had HDPE..
The best bowl ever, was the FingPaykel "Gentle Annie" which had a marvelous goblet spin bowl of stainless steel - simply the best

Most spin bowls are typically stainless sides and plastic base and top or perhaps white-metal base..
Good for nothing..
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STOP PRESS..

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I just started another bowl - this one to act as an MBBF.. (Post SF )

I feel that the Swirl Filter is working so well, I should just complement it with a similar Bio-Filter, and.. if solids gather there in, I can just "Pump" them away.

I had just got the Bearing Support Tube pressed out and though.. ".. but whilst the plastic is so hot and molten, why don't I use that heat.. to advantage...?

I quickly grabbed a short length of 50mm tube, JUST long enough to have say 50mm inside and 50 outside, and just ramed it through..

I had originally sought an engineering solution to making the hole bigger.. KISS, I forgot KISS..

Well, it just goes to show that there is often a better way , when you step back and look..

The 50mm inserted tube, just ploughed its way through the soft MD-PE, and there it stays..

So only thing to do now is to seal it securely in position and then I can use joiners or elbows or ???? on the two ends..

I can't believe how simple it really was..
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(EDIT.. VVV .. What's this attachment.. I have never seen that B4 )
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