I am building a wastewater system for my van (ie low pressure) and would like removable tanks for ease of emptying. I can shut off the inlet but would like to be able to drop them and automatically have them seal once the inlet is no longer connected. Lifting them back into position, the male inlet pipe pushes open the valve to allow flow to resume. Grey water only, no solids.

It's some kind of spring loaded valve but it needs to open with the mating of pipes and not water pressure. Probably, it doesn't have to be anything more than splash proof so no problem with seals. Right now, I can't even find the right term to look up.


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    $\begingroup$ these are called quick connect fittings for pneumatic and pressurized water. Don't know that I've ever seen one that would be fit for a gravity application. $\endgroup$
    – Tiger Guy
    Aug 31, 2021 at 15:03
  • $\begingroup$ Thanks for that. I can now start some research into the size of the drain hoses (1.5" in the US so I'll find a UK compatible) and see if they make one. If not, I may see if I can do something with a flap of thin rubber and see if the weight of the water in the tank holds it in place. $\endgroup$
    – Mike
    Aug 31, 2021 at 17:56
  • $\begingroup$ The normal gadget is a manual knife valve. etrailer.com/RV-Waste-Valves/LaSalle-Bristol/34466N4BB72GM.html. Note, these things last longer if they are operated regularly. A sewer valve that is only used one a year is going to be trouble. $\endgroup$
    – Phil Sweet
    Aug 31, 2021 at 18:50
  • $\begingroup$ I used those with a fixed tank but dumps are rarer in the UK so I want to be able to remove them and dump them wherever I can. What I'm trying to come up with is a 47L cassette. I'm thinking of a check valve in a larger diameter drain pipe (valve higher up) and a neoprene gasket. $\endgroup$
    – Mike
    Aug 31, 2021 at 20:10
  • $\begingroup$ Try this, though don't know if the sizes go big enough for you... cpcworldwide.com/Portals/0/Library/Resources/Literature/… $\endgroup$
    – Pete W
    Sep 1, 2021 at 0:45


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