Anit-Siphon Loops - How do they work ?

[Anonymous]

Re: Anti-Siphon Loops - How they work

[ QUOTE ]
I have also seen a small hole used as Lemain describes - small enough to not need ones finger to go over it. I believe that what Lemain is describing (perhaps he can say if this might be so) is that the valve is extended upwards on a piece of hose so that it will not tend to dribble through the small hole when water is passing through the loop.

[/ QUOTE ]Well, John, I'm not quite at the dribbling phase myself /forums/images/graemlins/laugh.gif What I've got is a loop of transparent pipe that loops upwards - like one of the humps on the Loch Ness monster. On top of the hump, the pipe has been cut and a plastic fitting inserted. This fitting seems to be a straight-through with a small hole on the top. If you put such a device on the outlet of a pump, then you'd get a spray of water coming out from the device, like Moby Dick. If you put this on the foul outlet of the toilet the consequences would be indescribably disgusting. One added part of this 'device' is a white plastic object in the pipe connected to the suck side of the device - this seems to flow with the water and floats back up to the device during pauses. I suspect that it is to prevent foul water from getting into the flush circuit should a gross defect have occured in the toilet. Aside from the little white plastic valve, you could probably achieve the same result by drilling a small hole in the plastic pipe, but then you might get a little dribble, I suppose.....

We don't have any dribbling on my boat, of any sort /forums/images/graemlins/laugh.gif

David

 

[Ships_Cat]

Re: Anti-Siphon Loops - How they work

Not familiar with the little floating bit whose purpose is probably as you say, but all else sounds as I imagined it to be. Thanks.

John

 

[HeadMistress]

Re: Anti-Siphon Loops - How they work

David, I believe what you're describing is type of air valve...it allows air in, but nothing out...and the little ball closes the vent when the toilet is pumped.

 

[Anonymous]

Re: Anti-Siphon Loops - How they work

[ QUOTE ]
David, I believe what you're describing is type of air valve...it allows air in, but nothing out...and the little ball closes the vent when the toilet is pumped.

[/ QUOTE ]Peggie, that makes a lot of sense. I can't see any ball valve in there but it's pretty inconceivable that there isn't some sort of one-way valve. I should think that's a requirement since some types of toilet can fail in a way that allows the foul water to be pumped out of the inlet. I seem to remember that the Simpson Lawrence SL 400/401 could do that on occasions.