[PSUBS-MAILIST] G.L. summary Pressure Hull

I am pretty sure GL and the other classes like a hatch, OP, AOP solution
without electronics a lot more.   

On Euronaut there is a manual ballvale as Overpressure valve integrate in the hatch
and a red label on the hatch handle "Never open before equalize". 

Its not with the rule because we assume the operator is able to read a red label - but for us it works. 

 In case I had to build something with the rules I just will block with the ballvalve handle in close position 
the hatch handle or the latches. 

Another way could be to design the hatch latches that way on a tread handle 
that you have to turn the whell some turns and it gives the hatches only a litte opening  to equalize 
and gives the latches later complete free with more turns. 
In that way you can open the hatch very fast in case in the batterey get very hot below your feets.. 
And you can still blow your ears drums away in case you like that.. 

vbr Carsten


"Jon Wallace" <jonw at psubs.org> schrieb: 

Advantage: ABS

I think the sentence being scrutinized may perhaps just be badly worded.  With the exception of some intricate mechanism that equalizes as part of a sequence to open the hatch as Jim suggested, I don't see a way to comply with the requirement without the involvement of electronics.  Philosophically I don't think I want to rely on an electromagnet or boolean logic giving me permission to exit the vessel.  If Jim's mechanism turns out to be to complicated then Doug's concern is valid...remember Apollo 1.

Jon


On 12/11/2013 4:17 PM, Alan James wrote:

Hi Doug,
Elaborating on your idea.
If you had digital pressure gauges you could have a system
comparing the voltage of the two, & when they were in a 
similar range they would activate or deactivate an electromagnet
that pulled back a latch that was impeding the movement of the hatch
release mechanism. (car door lock mechanism) You would
need a manual over-ride. Any electronics nerd could do this easily
& the car lock mechanisms I've seen for round $20-
With the over-pressure valve set at a couple of psi you know

that on the surface the most over pressure there could be is
what your over-pressure valve is set at. Under-pressure is
not such an issue as you won't be able to physically open the hatch 
if the under pressure is too much, & hence you have to equalize.
So I don't think it needs sophisticated monitoring. 
I'm not sure how much of an issue it would be if you opened your
hatch with a couple of psi over-pressure. Would the dome fly
open at 90 miles an hour, or would pressure be released incrementally
as the hatch dogs unlatched before fully releasing.
Obviously G.L. thinks this is an issue.
Alan




 

-- 

Carsten Standfuß
Dipl.Ing.Schiffbau @ Meerestechnik
Heinrich Reck Str.12A
18211 Admannshagen Germany

+49 (0) 172 8464 420
WWW.Euronaut.org
Carsten at euronaut.org
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