Maybe I am Crazy But ...
You know, those things in your link Jan aren't really anything more than fancy (and probably a lot more expensive) versions of the little fingers that reside in the bottom of your sand pool filter. In your filter the water is pumped into the tank full of sand from the top. A tube in the center has generally 8 fingers that extend out from the bottom, plastic pipes basically about 1/2 in diameter and anywhere from 4-8 inches in length filled with little slots. The water is able to enter into the slots under the pressure being applied by the pump, but the sand is not. So debris is trapped along with the sand, and clean water minus the sand returns to the pool.
It would seem to me it would not be too difficult to fit the intake of your well pump with a number of these fingers using ordinary plumbing parts. I repaired our filter that way with some new fingers and then some gas pipe/water connecters a few weeks ago. Bought all the parts at Ochoa in Santiago. They sell an octagon shaped black plastic end cap for a 1-1/2" tube that has 8 threaded holes to screw in the fingers. They also sell the fingers. But the fingers they sell are the wrong size for the end cap. Hence the other parts to reduce the size of the fingers to fit the holes on the end cap and lots of time explaining to the guys in the gas/pipe section what this plumber's nightmare I was creating was for. But it works perfectly, just like the original fingers.
If you have relatively easy access to the intake pipes in the well, it'd be worth a try since the fingers go for only about $100 pesos each, and the whole little assembly with the end cap, fingers, and adapters would cost $1500 pesos or less.
Tom (aka XR)
