From: "James Kocourek" <kocpnt@lakefield.net>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: Re: [PSUBS-MAILIST] Re: Life Support
Date: Fri, 13 Jan 2006 20:05:35 -0600
Hi Harry,
I've just been following the PSUBS mail list for a couple of days, however
I've been planning on building a sub for many years and am about to start.
I noticed that you mentioned your sub has been tested to 540 feet. That is
in the area of operations I would like to persue. I am looking for an
opportunity to share some ideas and pick the brain of people who have been
there. I would like to look at a sub capable of this type of depth prior to
finishing my plans. I live in wisconsin but could travel most any place in
the US. Please let me know if you can help.
Jim Kocourek
----- Original Message -----
From: Dan H.
To: personal_submersibles@psubs.org
Sent: Thursday, January 12, 2006 10:14 PM
Subject: Re: [PSUBS-MAILIST] Re: Life Support
Harry,
No, I don't have any O2 measuring device in my sub at this time. What
I based twenty minutes with two people on is, the designer of the K sub
Captain Kittredge dove for years venting every hour and had no problems.
John Maynard told me he once sat in his K-350, with a person monitoring
from outside, and he had no ill effects for five hours.
With that to go by, I figured John at rest may burn about half what I
would burn actively operating the sub so that gives one active person two
and a half hours. To be on the safe side the Captain suggested surfacing
every hour with one person so with two I open the hatch every half hour.
Twenty minuets down and a few minutes back and to unlatch. If I'm diving
alone, I vent each hour. Maybe not very scientific but proven.
I intend to add O2, a scrubber and a monitoring system some day.
Entanglement is by far my biggest fear. It's been on my mind even through
the building phases where I tried to reduce snags, if possible, and is
foremost on my mind when diving. So far I haven't been deeper then I could
safely escape from the sub. Now that the hull was tested to 540 feet, I
know I'll want to go deeper.
I guess a O2 monitor could detect if I have an O2 leak and it's rising.
Actually, if I have a leak that is more then I would absorb, I would hear
it when submerged. I would probably hear a leak before it would raise the
O2 level. It's really quiet down below.
I know O2 supports combustion, but it's not all that dangerous. You
want to keep it away from any ignition sources and keep the lines and
valves oil free. Sure, if you have something that gets hot it will burst
into flames in a oxygen rich atmosphere far faster and more furious then it
otherwise would, but things don't just go BOOM because they come in contact
with oxygen. If it was that sensitive, I would never have to strike a
spark to start my torch. Acetylene is a very volatile gas, but mixing it
with pure oxygen won't make it ignite. If I am using the torch and get a
"flame out," I can blow the combine gases on a hot piece of steel an it
reignites, but if the steel is under about a thousand degrees F, it won't.
I'm not saying you can't have big problems in an O2 rich environment,
but it's not a bomb unless something gets it, and something that can burn,
hot.
I routinely get oxygen for industrial use. My supplier has a manifold
distribution system that he hooks medical cylinders and industrial
cylinders to. I don't see any difference in what they get filled with but
the medical cylinders look cleaner. They may be cleaner inside also, but
I'm only guessing.
Most likely If I purchased a small medical cylinder from my supplier, he
would fill it repeatly with no problem since he knows about my sub. But
your correct, here in the USA you need a doctors prescription for O2 for
medical use. But, I used to get the cylinders refilled for our community
ambulance with no questions asked so I don't think their real strict about
it. It's not regulated like pain killers and stuff like that..
Scrubber, O2 and a monitoring device is soon to be added to my sub.
Dan H.
----- Original Message -----
From: Harry Spillett
To: personal_submersibles@psubs.org
Sent: Thursday, January 12, 2006 12:14 PM
Subject: [PSUBS-MAILIST] Re: Life Support
Dan,
As of yet, I don't have a scrubber or O2 supply in my sub. For now, I
never stay down with two people in the sub over twenty minutes. That's my
rule. I set a timer and return to the surface when it times out. So in
actually, it's about thirty minutes from closing the hatch to opening it
again. There is a pretty good cushion as I do it. Besides, my wife is
more comfortable with me touching base on a schedule like that. (she
muttered something about the life insurance not being paid up or something)
I had considered an O2 tank when building my sub. It would be nice to
extend my bottom time.
Even though you do not have O2 on board do you still have gauges to
measure CO2 and O2 content in your sub to back up your 20 minute dive rule?
Kittredge used to carry a 02 tank inside his sub, and then after the
space capsule disaster, he moved it outside and piped the O2 in through a
hull penetration to a valve in the sub. I was debating when building my
hull whether to put the through hull in or not. My thoughts were and still
are; a tank inside the hull is not leaking or it would be empty. A tank
outside of the hull would have to be turned on before putting the sub in
the water. The valve inside the hull may be leaking a bit and I may not
know.
I would have thought if you had the contence gauge inside with you,
along with a separate O2 monitor you would be able to detect a leak and act
accordingly.
Unless the tank or valve ruptures, I don't see the danger of it being
inside the sub. I know it's not leaking O2 at the time I'm in the sub if
it has sat in there for a month or so already. If I want to extend my
bottom time with supplemental O2 and discover my tank is empty I have to
surface and go back to my twenty minute schedule. I could carry two
smaller medical tanks.
I believe the ABS regs state that gas cylinders should be mounted
outside so that a leak will not increase the internal pressure to a toxic /
dangerous level. By the same token the volume of gas stored in internal
pipelines should be kept to a minimum (by the use of regulators or short
runs of pipe) so that if released it will not increase the internal
pressure beyond a certain level. This all seems to make sense but it does
mean at least one more penitrator through your hull and another stop on the
inside.
H
Any thoughts?
Dan H.
----- Original Message -----
From: rick miller
To: personal_submersibles@psubs.org
Sent: Wednesday, January 11, 2006 9:41 PM
Subject: Re: [PSUBS-MAILIST] Life Support
harry
The normal human consumes about one cubic foot of oxygen per
hour and will feel no effects of oxygen deprivation at an o2 level above
18% the osha level is 19.5% minimum. air contains 21 % o2. So dependent
upon the size of your cabin you need to run the numbers to see how much o2
you will have.
A co2 scrubbber can be made from a piece of plastic pipe with
screens at the end to hold the absorbent. mount a fan at the top and for
under 100$ you have a co2 scrubber.
one caution when using o2 addition it does make things burn
rapidly. and abs says that o2 tank most be mounted outside.
fire and o2
the biggest problem using pure o2 is the risk of fire in the
system piping. high velocity o2 can ignite lots of things . needle valves
are used here. Trust me on this i turned a rebreather in to a flame thrower
the hard way.
most valves can be ordered o2 clean and should be, the packing and
grease needs to be o2 compatible. yes o2 needs a special grease. piping
will need to be cleaned prior to use. I have had success with hot soapy
water wash, repeat until clean then hot water rinse and cap lines until
installed.
hope this helps
rick m
----- Original Message -----
From: Harry Spillett
To: PSUBS Mailing List
Sent: Wednesday, January 11, 2006 2:51 PM
Subject: [PSUBS-MAILIST] Life Support
Hello folks,
It has been a long time since my last post but I still have
questions!
Is it correct to think that in an enclosed space, like your
pressure hull you will suffer from the negative effects of excess CO2
before you suffer from a lack of O2? What I am getting at is, could you
upgrade a simple sub with no life support by adding just a scrubber to
extend your usable bottom time or would you only gain a little bit of extra
time before the O2 would need replenishing as well.
What sort of equipment is used by those of you who do replenish
the O2? It is sufficient to have an O2 tank, conten gauge, regulator (and
gauge?), and a flow meter (with a separate O2 sensor and meter). Or does
the equipment need to be more sophisticated than this.
What do you do about "oxygen cleaning" Do you have to just
concentrate on the O2 supply kit or all of the equipment within the sub?
How many of you provide yourselves with CO2, O2, and internal
pressure gauges to monitor the environment but do not fit additional life
support.
Thanks in advanced guys,
Harry