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Silly Putty Pump for household grey-water

It’s green, Corbin, super-green!
  (+5, -1)
(+5, -1)
  [vote for,

I am desirous to use my waste household water for other purposes, like watering my garden. Our use of environmentally safe cleaning compounds would not preclude us from using this water in the garden. But the effort does.

My main problem is that *green* grey water systems (or is that grey-green or aquamarine?) are gravity fed. The first stage of particulate removal is above the second stage settling tank, the final collecting stage is situated below the second stage. All the stages are below the intake from the household. Given that I live very close to the earth’s surface, this means my usable grey water is somewhat below my elevation of use and re-use.

I need some head (marked SFW in this context). This means I have to pump the water, either as and when I need it, or perhaps into an elevated storage container. This requires energy, which I have to admit could be supplied by me exerting effort to pressurise a spray container. But that seems too simple for a ‘bakery idea, and too taxing on my limited energy reserves. I now have to eat things that have fallen to the ground to reduce my carbon footprint.

Something in abundant supply, here at the surface of Earth, is gravity. There are those that propose it is plentiful everywhere, but I digress. I propose a Silly Putty, Specific Gravity Pump.

In its simplest implementation this would consist of: three tanks (containment vessels to avoid ambiguity), some small diameter piping and some valves. The first two tanks are at 90 degrees to each other on the vertical plane and rotate about an axis of 45 degrees and connected by the small diameter piping. To verbally illustrate: think of the first tank’s centre at coordinates (0; 4) and the second tank at (4;0) The third tank is also situated on the vertical plane at about ( 6;4) given a specific gravity of 1.4 for silly putty, and *temporarily* connected to the second tank. The tank on the “y axis” contains your dense silly putty. The tank on the “x axis” contains your gravity fed grey water. Closing the inlet of grey water and opening the inlet for the silly putty allows the silly putty to flow into the second tank. Displacing the water up into the third tank. When as much of the water is displaced as is possible. All valves are closed. At this point you could then make use of your elevated grey water.

To repeat the cycle. Disconnect the third tank from the second, and rotate the first and second tanks around their 45 degree axis of rotation. Now the second tank containing silly putty is the first tank and second tank is ready for grey water input. Reconnect third tank to the now second tank. Allow second tank to fill with grey water. Repeat.

So for a dense silly putty at x meters you achieve a displacement of water to x+n meters (where n is a function of the density of the silly putty). The more dense you can make the silly putty the more elevation you can achieve in the third tank. The less viscous your silly putty, the faster you can repeat the cycle.

1) Any intimations that silly putty has a greater carbon footprint than me pressurising a portable chamber will be ignored. 2) Mercury, gallium, or some such, would be ideal for their viscosities and specific densities, but are harmful and/or expensive. 3) Virtually no animals were harmed in the creation of this idea. 4) Does not include batteries, may contain nuts, parts sold separately.

4whom, May 29 2009


       [bigsleep] don't throw the baby out with the bath water. I urge you not to pull the plug on this, unless you think it is really circling the drain.
4whom, May 29 2009

       I gather the requirement for the silly putty in this proposal is that it flows, is not water soluble, and is heavier than water. Would gravel or pebbles suffice?
BunsenHoneydew, May 31 2009

       [Bunsen...] I did think of gravel, etc. Even tiny glass beads. The original idea came from an hourglass, for example. However, sphere packing limitations and the propensity for granules that are not spherical to "trap" water (hygroscopically), led me to a more "solid" liquid material.
4whom, May 31 2009

       You quoted 5th element. On a day like today, [+].
Custardguts, May 31 2009

       I've done some experiments that suggest silly putty actually is slightly water-soluble.   

       Also, if it's denser than water, won't the effort needed to lift it between cycles outweigh the effort needed in using some other pump to lift the water manually? Unless the silly putty pump proves more efficient than the others.
ye_river_xiv, Jun 01 2009

       Out of interest, why do you want to remove particulates? Once settling tanks and so forth are added, the complexity and costs can quickly outweigh the relatively low value of the greywater, financially and environmentally.   

       I use settling tanks on my stormwater to remove heavy metals in the form of paint and road dust, but that shouldn't be needed for household water.
spidermother, Jun 01 2009

       [ye_...] It is disturbing that my *miracle* ingredient is soluble. Well we have to make it more dense anyway, this idea works better with specific gravities greater than 1.4. Maybe we can make it more hydrophobic too?   

       It takes just as much work to lift the silly putty to a y axis value of 4 as it would to lift water to 6 (approximately). No free lunch here. I have toyed with the following as a workaround.   

       When all the silly putty has displaced the water in the second tank, the first tank remains empty and elevated. I suggest this becomes the grey water container until full. That means we only do work to raise the mass difference between the two liquids. It does, however, impact the height we can raise the water above the grey water inlet. And makes a more dense liquid piston a must.   

       [supercat] we are running our sink water to the grey water. This has bits of biomass (veg, meat, pasta, rice, etc) Some of these float, all of them rot. So we filter off particulates with a nylon sponge that floats on the water level. It is not very sophisticated, but it does get rid of lots of potentially smelly bits.
4whom, Jun 01 2009

       ..and the garden at (0;x)
4whom, Jun 01 2009

       If you end up with water somewhere above the level it was before, you added energy. This energy has to be put in, so i do not see the need for the silly putty. Just swivel the tank of water up, if needs be use a small solar patch, a motor and an insane gear ratio.
loonquawl, Jun 02 2009

       [bigsleep] but then you have tap water below where you want it.   

       [loonquawl] technically you are right. As I said, I should take a portable container, pressurise it, and water my garden. I should use an archimedes screw powered by the sun or wind. I should use small demand pumps powered by the sun. None of these include silly putty, or dense viscous liquids. The thought experiment is as follows. Given a restricted area I would like to elevate my water. I could do this by creating a circle that would elevate my water, the circle having radius half the elevation height. Or I could use a dense viscous liquid and reduce the diameter of rotation by a factor related to the difference in the specific gravities of the two liquids. I can further reduce the circle to just a cone based on this radius, by placing the tanks at right angles to each other. Given that it takes the same amount of work/energy, I could hook this up to some gearing and solar power source. The point being, I only rotate arond a smaller radius for the same result. I imagine that gravity is pretty efficient by now, after 13 billion years of tweaking.
4whom, Jun 02 2009


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