Backyard Aquaponics
A place to discuss aquaponics

Here is a pic of the original bell siphons that have worked without a problem since setting up the system in November last year

And here is the Affnan siphons that have replaced the Bells

Hey DR, I still say your original bell is an Affnan with a breather hose, it still has a funnel (reducer) on the top there for I recon falls into the affnan catagory

Hi Simo
While both types have a funnel reducer the difference is the affnan has a greater volume in the internal area of the stand pipe in relation to the volume between the outer area of the standpipe and the innner area of the bell, it is critical that the former area is greater than the later. I think this is the fundamental difference between the two.
Another difference I have observed with the air tube on the bell and the hole on the Affnan is that the inflow of water from the Affnan probably assists with the quicker siphon action as it creates a restriction and greater turbulence inside the standpipe.

Hey, just ran out of battery in my camera so will put up pics of my siphon tomm. Its pretty much as the same as the first one that desertrat posted in as much as it has a straight standpipe with a funnel at the top, only mine has a 1 3/4" to 3/4" reduced on top rather than a funnel.

With regards to it being an Affnan siphon, the innovation that Affnan found was manipulating Bernoulli's equation, as his blog explains. So any reduction in diameter of the standpipe causes the power of the siphon to increase. Therefore both those siphons that you put up are Affnan's desertrat, as both take advantage of Bernoulli's to increase siphon power. The outside dia to inside dia of the bell is a separate innovation that Affnan has thought of but not tested as his blog states, his innovation takes place inside the siphon at the point where the dia of the pipe is reduced, not outside. The fact that it is easier for the siphon to break due to the small amount of water standing around the standpipe is merely a byproduct advantage of his innovation, not the crux of it.

Anyhew, I may be wrong, why don't we get Affnan onto the forum and make sure...?

I think he is too busy, what with being a genius and all

My first system (and my intro to AP) is recorded here ...

viewtopic.php?f=18&t=6680&st=0&sk=t&sd=a&start=60

I was encouraged to make a "mega-siphon" by chainsaw and it has turned out, and works, very well. Some specific photos of it today ....

(Later, I'll make another post based on my new system with a couple of mega-siphons BUT the bell is suspended from the top).

In both systems I use a bleed valve just for the purpose of letting the air out of the bell as it is pushed over the standpipe. Once down and all air expelled, I close the valve and leave it alone (oh well, I do have a fiddle now and then ).

My new system is still WIP .... It took me a week to get the siphon working exactly as I wanted.

Basically the mega-siphon consists of 90mm outer casing (storm water pipe). The bell is 85mm DWV with an end cap. Standpipe is 25mm (and can have a 40mm reducer on top - but I found it is not really necessary - works very well without it). The base of the 'T' piece is blocked with a 90mm end cap. A 25mm hole is drilled through the cap and a 25mm threaded socket fitted. This is then screwed into a thread 25mm (F) 50mm (M) adapter with another adapter to slide onto the 50mm pipe to the ST. This is buried in the ground and emerges at the side of the ST.

I have managed to tweak the siphon so that it starts just as the water reaches maximum height in the GB (adjust standpipe length) and cuts off as the level reaches the bottom of the plastic tubs in the GB. (adjust length of the bell).

Argh yes .... some photos ....

and I need some volunteers to help wash gravel .....

OK here are a couple of photos of my Mega syphon connected to 6 half barrels.

I utilise the screw on cap as top of the bell and then just cut the length of the bell pipe required, glue it in place and ensure it has an airtight seal (can even run a bead of silicone around it for good measure). When it is screwed on the bottom of the bell is the cutoff point, no need to cut slots etc. it is suspended at the right level, no air bleed tube, havent found it necessary. Dont have problem of airlock blowing bell out either. Can use an Affnan funnel standpipe with it if needed, I dont have a problem with starting as the rate of water rising in the GB is sufficient (ie pump flow).

If water flow is too great and syphon wont stop I use a little air bleed on top of the bell (little yellow valve) stick a bit of 4mm airline on it (stephascope) listen to what goes on and introduce air until stops. Dont really need it on mine but thought would mention it if people are having stopping problems. AND dont forget a vent hole can be on outer edge of screw cap or through the side of outer casing (at the top).

Later will post some drawings for members use (Ian K is kindly drawing some up)

Abdul you explained it perfectly....

Affnan

Oh hellooooo! Praise from Caeser

Absolutely fabulous to see you here Affnan, you rock!

And here are pics of my siphon, built and adjusted quickly and easily all thanks to Affnan's terrific blog

Hey Abdul,

I think the hole in your protector or gravel screen might be too large depending on the size of the rocks you end up getting.

Why did you put the air break tube on the Affnan? I did not find this was needed when I built my Affnans

Abdul

your reducer on top of the stand pipe look a bid doggy. It may not be as efficient as it should if the funnel part lack gradient. If its a square reduction then it will generate a lot of restriction, back pressure and turbulence.

Air break tube together with funnel siphon,, you must have inherit it much from the "Brits" Belt and Suspenders concept. Anyway its a hybrid then.. who knows it may make it even better to have hybrid, especially for those that cannot find exact parts to reproduce my basic design.

What ever it is Abdul.. keep on testing and refining.. we are all learning, and in my opinion you have did a right thing by joining this forum. There are many experience individual here, I learn al lot about AP here. There are different ideas, this is a good thing, because we will never stop learning.

As a teacher I must say.. the moment we stop learning.. that's when we are starting to die.

Cheers.

Affnan

BTW.. Joel started this thread for pictures of siphon... keep em rolling.

The holes may indeed be a little too large, will adjust that once I get my grow media finalized today.

I added the breather tube as it was having trouble breaking the siphon due to high flow by the pump. The actual system will actually have much lower flow than in my tests but I just wanted to make the siphon bulletproof. Moving towards a policy of making it 'safe' rather than 'not unsafe'.

The reducer is a bit dodgy Affnan, during tests I found that the restriction with the elbow at the bottom was needed in order to get it to start and the breather tube in order to get it to stop, no change with and without the reducer, though what i did notice was, that when the overflow started without the reducer, water level still increased in the GB for about half an inch before it started slowly falling, with the reducer the second overflow started the level in the GB started to go down, overall it did seem to aid the siphon establishment but it was in no way critical. Time will tell whether I've managed to make it bulletproof or not, but as per my reading it has all the tweaks added that we know of.

Regardless, pictures of other people's work is immensely educating, and I wholly agree with Affnan that we must keep learning.

Three cheers for the BYAP forum, hip hip HUZZAHH!!!