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Re: [PSUBS-MAILIST] underwater supersonic vehicles



For those interested in supercavitation, supersonic torpedoes and other fast moving projectiles under the water there is an interesting article in Scientific American .com
http://www.sciam.com/article.cfm?articleID=000CA29B-0EA6-1C70-84A9809EC588EF21&pageNumber=1&catID=2
 
Also about gas turbines and jet propulsion systems burning metal fuels (aluminum, magnesium or lithium) and using outboard water as both the fuel oxidizer and coolant of the combustion products for propelling supercavitating vehicles to high velocities.
 
Herve

----- Original Message -----
From: Alec Smyth
To: personal_submersibles@psubs.org
Sent: Wednesday, January 08, 2003 11:14 AM
Subject: RE: [PSUBS-MAILIST] Alec, Scrubber

Please see below...
 
rgds,
 
Alec
-----Original Message-----
From: Dan H. [mailto:JMachine@adelphia.net]
Sent: Tuesday, January 07, 2003 10:30 PM
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] Alec, Scrubber

Alec,
I was looking at the pics of your scrubber and have some questions. 
 
Your fan motor is in the half with the clear canister, correct?
[Alec Smyth] The clear can contains sofnolime. Its clear so I can see the change of color.
 
It looks like the fan is mounted in the white plastic.  Am I correct, or is the fan inside the black housing?
[Alec Smyth] The white plastic contains two fans. The U tube puts them in series. If one fan quits, at least the other continues pushing air through both cans. 
 
If the black housing doesn't contain the fan, what is it for?
[Alec Smyth] Well, for one it came with the proper thread and airtight seal for the canister to screw into! (taken together, the black and clear part are nothing more than a wet-environment industrial lamp from the MSC catalog) But it has several other functions too. It contains a stainless spring-loaded device that presses a perforated disk down on the Sofnolime to keep pressure on it, so tunnels do not form in the material. It also makes the clear canister draw from lower down. CO2 goes to the bottom of the hull. The scrubber draws air in vertically through holes in the bottom of the clear canister, and expels it horizontally through the bottom of the secondary white canister. And finally, if my fans were stong enough -- which unfortunately they are not -- it also just happens to be the right size to accomodate a standard respirator cartridge of activated carbon, which is good for eliminating odors or anything else should the air be contaminated.
 
What is the clear canister below the black housing for?
[Alec Smyth] So that I am not sucking in the air I just scrubbed. 
 
Why didn't you just mount a fan on top of the white plastic pipe fittings containing the scrubbing agent instead of using the U tubing? 
[Alec Smyth] The whole idea of this scrubber is that the fans are completely enclosed by sofnolime in order to keep it quiet. The ratio of volumes of the canisters is about 3:1, which I found made the sofnolime in the entry and exit canister get used up at about the same time. You need less sofnolime in the second can because the air that is entering it is already scrubbed by the first.
 
 
Thanks,  Dan H.