Posts by Fingerless Pyro

Suck versus Blow

To everyone who yammers on aghast about the pumps being in the basement, and how it's a horrible design: there's a very simple reason why they're there. It's called basic physics. If you are trying to get fluid from a low level to a high level (and please God don't try to suggest the diesel tanks should be anywhere but the basement) you have two ways to do it: suck or blow. If you want to suck it up (i.e., have the pumps up high) you can only raise it up until the head pressure equals the vapor pressure of the fluid. For example, if you're trying to suck mercury up a tube, you can only raise it 760mm (assuming you're at sea level). After that, you simply have a vacuum over the top of the liquid (actually mercury vapor, but that's pretty close to a good vacuum). You simply can't suck it higher than that. Water, (and diesel), being less dense than mercury, can get sucked up higher, but you can only go so high before again, you only get vapor, not fluid.

The other approach is to blow. Put the pump inlet down at the lower level, and then you can send it as high as the outlet pressure of the pump can push it. Given that pumps can easily hit hundreds of PSI (and thousands in the case of hydraulics), you can push a liquid far, far further than you can pull it.

So for the love of all things holy, please quit saying how horrible a design it was to put the pumps in the basement. It's the only place they can really do their job.

However, feel absolutely free to question why the pumps weren't waterproof (or submerged in the diesel tanks), along with watertight electrical feeds to them. Now THAT is a horrible design.

Mopping up the scraps?

So if Google is going to get 21.2 percent, Facebook 15.5 and Yahoo! gets 7, that leaves 56.3% of the market left. Seems rather poorly worded to imply that those three have between them gobbled up all but 'the scraps".