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Hey
guys,
I
assume that just about everyone here is limited in funds to build your sub. The
more complex systems are their likelihood to fail is higher and the cost of
repair is equally expensive. An O2 System does not have to be so complex, all
you need is a needle valve in series with a flow gauge (calibrated for O2) for
you to set the proper flow. There are all kinds of portable O2 monitors that you
can get for $200 bucks and that is what you use to keep an eye on your O2. They
even have Low and high and low level alarm settings which if set properly will
give you plenty of time to adjust your O2 flow.
In my
personal experience with many submersibles I have yet to see an automatic
computer-controlled O2 system aboard any of the submersibles that I have worked
with. And the comments I have heard from the ones that do have it is that they
are a pain in the ass to maintain. I am not against it as I am a tech junkie
myself. However one must ask the question..... Is this really necessary? Do I
really need it? Or is it just a gadget I like?
The
JSL sphere is roughly 55 cuft and I rarely ever have to make an adjustment to
the O2 system. I have even turned off the O2 to see how long it takes to trigger
a low alarm (Ours is set at 19%) and it takes about 30 minutes to drop 2%.
However, it is a good piloting practice to monitor your instruments constantly
(every 5 minutes is a good ballpark figure). I guarantee that this practice
alone will keep you out of trouble and on top of your life support system
with very little maintenance..
Any
ways, just a thought...
Hugo
-----Original Message-----
From: rick miller [mailto:rickm@pegasuscontrols.com] Sent: Monday, December 19, 2005 1:22 PM To: personal_submersibles@psubs.org Subject: [PSUBS-MAILIST] o2 control brian
the sensors that you are looking
for are teledyne analytical instruments
class r-22d, o2 sensors. they put out a milli volt
singal directly perporsional to the amount of o2 present the average
output is 7-13 mv in air at stp. the need to be loaded with a 10k resister.
Measure the output with a milli volt meterany kind will do. if the voltage drops
ten percent you know that your o2 levels droped ten percent.
o2 control can be done three
ways.
1.o2 level monitoring with a
solinoid for injection
pros hands
off automatic control
cons
expensive and complex
2. automatic pressure controller
maintain sub internal pressure to a fixed
point
pro single
controller all mechaincal/ about half price of electrical
con
compressed air leak internal inside sub will shut down system
3. adjustable flow controller
manual
pro
cheapest
con requires
continous monitoring
hope that this helped for your design
ideas
rick m
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