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Re: [PSUBS-MAILIST] Isn't 'Mini book review.' anymore--pressuretest
At 14:37 +0200 4/11/02, Thijs Struijs wrote:
>I agree on John. Water is not compressible. This means that in the case of
>a rapture it doesn't expand (=explode) either.
I wouldn't normally comment on typos or understandable ESL difficulties, but this one is just too cute! ;-) We must all plan our boats to be able to deal with ANY contingencies, eh?
On the topic of water rockets, it seems to be the only reason air would be introduced into a pressure tank, is like in your house if you have your own well and pump -- it provides more stored pressure. It doesn't make it easier to get it compressed, having something to compress just gives you more of a "sink," sort of like a big spring or a similar effect to a large volume head without having to pump a lot of water up to the roof. Without the air in your precharged pressure tank, as soon as the closed system was filled up, it would be at full pressure, and as soon as you turned on a faucet (or opened the valve on your water-rocket), the pressure would be mostly gone. With the air getting squished, it takes a while to build up to operating pressure -- but longer to use it all up without the pump running.
--
David
buchner@wcta.net - MN, USA
http://customer.wcta.net/buchner