I second this. The only way I have so far is making a vacuum at the top, and a higher pressure or 0 pressure at the bottom, but it only works for a few minutes, even with indestructible wall and white hole/black hole.

What do you mean? It works fine for me on acid, water, or Liquid Nitrogen to use the "straw" method, but only on a large scale. For a small scale, its too hard to make enough of a pressure difference.

The trick is putting the "straw" of wall deep through the inside of the container you're trying to pull liquid from, and to put a bulb of solid wall at the top, so vacuum can't escape. There also needs to be a place of extremely low pressure so that the liquid can accumulate, instead of clumping at the top of the "straw" otr float around the bulb. Then, decrease the pressure of the straw slightly, decrease the top bulb more, and the reservoir should have the most and largest amount of low pressure (in the for of black holes). If you did it right, liquid should flow from the bottom pressurized and closed reservoir up the straw, into the top bulb, and accumulate in the flask with the lowest pressure.

This is why its better to have a pump, the pressure system, while it works, is very complicated and inefficient, and you need a lot of black holes at very specific sizes.

If you can tell me how to embeds an image, I'll show you what I'm talking about.

http://img291.imageshack.us/i/pumpx.jpg/

tell me if you see it

Who says you need pressure? A wall that lets liquids through and pushes any particle in it in a direction through a small addition to programming (you could set the direction like fan) and they would pop out the other end.

This probably wouldn't be high on Simon's list but it isn't overly complicated to do like some other ideas either.

I fully support this idea, then I could make a liquid cooled engine.