Gravity Mill - any comments to this idea?

[ooandioo]

Allright, the idea is very good - if we are able to seal the shuttle sides so that no air is able to escape.

[prajna]

We can do that, as per my previous design, once all the figures have been calculated but it is simpler to consider it as a simple piston for now.

[hartiberlin]

Hi Pranja, good work with your calculator.
Well, one thing:

So we can pump 77754.42 litres on each stroke
using Ïâ,¬ r2 * (height of the pumping tube - height of the shuttle)

So now your are subtracting the height of the shuttle ?

Is that with the displacement area full of air or without it ?

Maybe you make better the main tube x meter longer when you
ask for the deepth, so the tube will be automatically 20 cm longer than
10 Meter, if one chooses 10 Meter deepth...

Then it will not be too confusing...

2. Also it would be better, if you draw your picture this way, that
you attach some open buttom case for the air displacement area,
otherwise one can not easily see, that air is expanded from the shuttle
down below the shuttle into the displacement area.

Many thanks for your hard work.

[prajna]

Stefan. I have changed it again.  Now it calculates the pumped volume by subtracting the volume of the total air required to lift the shuttle and the head from the volume of the pumping tube.  To save questions, this is the volume that the air will occupy at the bottom of the pumping cycle including the displacement of the shuttle.

The height of that air in the pumping cylinder will become important when we need to figure out how close to the bottom of the pumping tube the shuttle can go so I will also include the height figure in the results.  It also tells us the height of the shuttle including a skirt to contain the expanded air (which you suggested I show on the drawing).

[tbird]

had a short look again at your program.  with 15cm (+or-6inches) diameter and 30cm (+or-12inches) high (sounds like less than 1 cubic foot (64.7lbs)) the result is 53.01 kg.  doesn't that sound heavy to you?  maybe you need to use internal radius instead of internal diameter.

It is heavy, tbird.  That is because you have a much taller shuttle than you need.  What kind of head are you lifting?  If it were 1kg (2.2 pounds, I think) then you would need a much smaller shuttle.  Tell me the head sizes as well as the pump sizes and I will tell you a reasonable shuttle height.

How much does one cubic foot of water weigh?

unless i really don't know my metric values, 15cm diameter by 30cm high is only about (not even, 6x6square has more area than a 6"diameter circle) 25% as big as 1 cubic foot.  so 25% of 64.7 pounds (16.175 pounds or 7.35kg) doesn't sound like 53.01 kg (116.6 pounds).  what am i missing?

so there is a small passage outside the shuttle (still inside the tube) to valve 3?

your shuttle does get pretty close to elsa design.  if i see your shuttle right, the bottom of the tube will be open? to allow the shuttle to descend without moving water up threw exit pipe?

didn't see an answer to this part of my post.  should i quack?