Black & Gray Tanks

[family wagon]

Per the Fluid Compatibility Guide at Marco Rubber, NBR (aka Nitrile Buna-N) has "excellent" compatibility with sewage. Looking at the cross-section diagram on that valve's page, though, it's clear that the maximum size object it'll pass is much less than the 1-1/2" pipe it attaches to. Success might depend on how small the toilet grinds things.

Since you picked an electric valve it's obvious you want automation or remote control. What about a traditional bladex valve with a linear actuator? Maybe some Actobotics gizmos to build a rack and pinion, or a wheel with a lever attached (thinking along the lines of the drive mechanism on a steam locomotive)...

[Stu & Filo. T]

Originally Posted by family wagon

Per the Fluid Compatibility Guide at Marco Rubber, NBR (aka Nitrile Buna-N) has "excellent" compatibility with sewage. Looking at the cross-section diagram on that valve's page, though, it's clear that the maximum size object it'll pass is much less than the 1-1/2" pipe it attaches to. Success might depend on how small the toilet grinds things.

Since you picked an electric valve it's obvious you want automation or remote control. What about a traditional bladex valve with a linear actuator? Maybe some Actobotics gizmos to build a rack and pinion, or a wheel with a lever attached (thinking along the lines of the drive mechanism on a steam locomotive)...

I'm hoping that with a macerating toilet the particles will be small enough, I'm think an electric valve because my tank will be on the right side of the bus so I'm going to have a control panel on the drivers side. Full plan is & I know some people will think I'm silly but plan is pump out black tank, then pump grey tank into black tank to help clean out black tank & waste lines then pump a few gallons of clear water from fresh water tank into pump to final rinse pump & lines, yes there will be another shut off valve in fresh water line with spring loaded check valve before and after shutoff valve.

[family wagon]

That's pretty thorough! I wonder whether one pump could be eliminated by mounting the gray tank higher than the black, so that the gray-to-black transfer could be done by gravity.

What kind of hose do you plan to use for the final output? I have a Flojet 18550000A pump for mine. It has a barbed hose output. I used 1" flat discharge hose and found that it doesn't work very well. Where the hose has to bend it constricts a bit, and with the pressure of the pump upstream the constriction quickly becomes a hard kink and it's fiddly to keep the flow going. I'd like to stay with flat hose though because it stores so compactly.

[Stu & Filo. T]

Originally Posted by family wagon

That's pretty thorough! I wonder whether one pump could be eliminated by mounting the gray tank higher than the black, so that the gray-to-black transfer could be done by gravity.

What kind of hose do you plan to use for the final output? I have a Flojet 18550000A pump for mine. It has a barbed hose output. I used 1" flat discharge hose and found that it doesn't work very well. Where the hose has to bend it constricts a bit, and with the pressure of the pump upstream the constriction quickly becomes a hard kink and it's fiddly to keep the flow going. I'd like to stay with flat hose though because it stores so compactly.

Gravity won't work, far as final discharge my plan is to use ridged 1in from pump to a hose reel then use collapsible 1in hose off the reel, have a lever valve on the very end of that and keep some pressure in it while I roll it back on then open the valve to release pressure that way I wouldn't have to unroll the full length every time.