I've been experimenting recently with trying to stop wetness from the pelton side of the turbine creating dampness on the alternator side. There's a seal around the shaft which should prevent water in any quantity getting across but an investigation I've done using bags of silica gel indicates that in spite of the seal about 300mls per month still gets across.
These photos tell the story of the sequence of steps I've taken:
1. Limescale deposits on the shaft indicated that a considerable amount of water enters the top-hat labyrinth chamber
2. A V-ring seal (purchased here) was mounted on the shaft; the seal turns with the shaft and its lip seals against the plastic face of the top-hat, with the idea of preventing water tracking alongside the shaft
3. Inspection after 3 weeks running showed the seal had badly scored the plastic face of the top-hat, presumably from softening of the plastic by the heat of frictional contact, - I must have applied it too tight to the face.
4. A friend who is skilled on his metal lathe kindly turned a stainless steel cap to fit over the plastic top-hat so the seal rubbed on metal; the cap is held on only by being a tight fit.
5. Suspecting that water might also enter the top-hat via its drain hole, a deflector was devised to shield the hole from the upward direction of water leaving the pelton from the lower jet.
6. So the complete arrangement as it is at the moment looks like this:
Only time will tell if it makes any difference. The early signs are that the silica gel bags do seem to be taking up less water but I'm yet to be convinced this is a genuine observation.
Whilst I was working through these stages of development, EcoInnovation have come up with a slightly different approach:
Theirs is a neater solution but care will be needed not to apply the V ring seal too tightly against the face of the top-hat. The seal only needs to just touch. After observing the scoring illustrated above, a new top hat with the seal just touching ran for 3 weeks with not even a mark being caused. A smear of grease is also a good idea.
