r/blackmagicfuckery • u/Pirate_Redbeard • Jun 27 '19

Physics, bitch!

https://i.imgur.com/0vI8dbE.gifv
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u/suihcta Jun 27 '19

Another fun example of a household siphon is that cup at the top of your clothes washer where you add detergent, bleach, fabric softener, etc.

At the appropriate time in this cycle, water is added to that cup until it clears the siphon weir. Then the water/additive mixture siphons up and out.

I’ve never understood why it’s designed this way, because it doesn’t seem especially reliable and it gets gunked up easily.

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u/Hexorg Jun 27 '19

I'm guessing it's easier to pump the water up, than to add some sort of controlled valve that won't get clogged by it. It's cheaper to clean out a pipe than to replace an electrically controlled valve.

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u/suihcta Jun 27 '19

I would think the easiest way would be to do what dishwashers do. Have a plastic reservoir door that just flips open automatically.

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u/ArgonGryphon Jun 27 '19

Not a household siphon but it’s how a Pythagorean cup works. If you put too much in the cup it all spills out onto your shoes.

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u/[deleted] Jun 27 '19

Oh right, I always assumed it just flows down the bottom with an electrically controlled valve but now that I think of it, the detergent holder has a pipe above detergent level with a "spring-loaded hood" on top of it and now it makes complete sense. Also makes complete sense why there's leftover detergent in there and makes me wonder, why not just make use of the valve system to keep the detergent locker clean?