The following are pics of my bell siphon. It is based entirely on the Affnan siphon, which has several advantages, namely: it shuts itself off without the need for a cut-off air-hose, which are reported to clog easily; it drains faster due to the fact it takes advantage of Bernouli's Principle in its design, and for my time, it's much easier to make than a loop siphon or anything else I found.
Here's the bell itself. This can be made with a hack saw and some elbow grease, or if you're handy with a chop saw, you can make the horizontal cuts very carefully with a chop saw, and the vertical cuts with a hacksaw or jigsaw.
My bell uses a 4-inch pipe (100mm Imperial units). The siphon is a 3" - 1" (75mm-25mm) reduction connecting to a 1-inch pipe (25mm).
What is missing is a picture of the filter housing, which I will upload next time I'm at the farm. The filter is a 6-inch pipe with many small holes drilled into it.
The only disadvantage of this system is that the siphon, once it's fully assembled with its filter, takes up considerable space. This is amplified by the fact my beds are only 100-liter half-barrels. However, I am going to change my barrels to much larger grow beds (more on that later), and keep these bell siphons. That will reduce complications (bell siphons instead of 16) and provide more grow space.
Here I was just testing the siphon. The broken pieces of blocks are just to stabilize the barrel as it fills with water.