[PSUBS-MAILIST] O2 regulator
Hugh Fulton via Personal_Submersibles
personal_submersibles at psubs.org
Sun Jul 20 17:08:45 EDT 2014
Hi Cliff, IF you had been taking your sub I would have made the effort to
come across. Q-Sub!! Batteries!! Trying to get them sorted and I am on my
3rd lot and it has not been in the water. Biggest problem is I got them too
early and they have not been cycled regularly.
2nd problem is the gearbox. I contacted Mercruiser agent and asked which
direction did the driveshaft have to go before I made the gearboxes. He
told me I could run it either way. I belaboured the point to make sure as I
said I could do a gearbox to go either way. Trouble is I did not get it in
writing. Now after testing and pulling the top off I found I have to
redesign and remake two gearboxes to give same direction in as out. That
really taught me a lesson as well as making me angry as hell. Also had a
Kelly BLDC motor controller fall over and trying to get it fixed. A few
minor issues with wiring and controls which I expected. I have done some
nice LED lights 150 watt which are 2nd generation but are good to go. They
get a bit hot in air after 15 minutes but all good in water. Had some
problems with the engines as I had taken a feed off the crank sensor. Took
that off and they ran sweetly. Hydraulics needed pump changing out for a
smaller one. Again supplier fault. Getting there but as you say,
complexity = extended time. All-a-same-engineering, Boss!!
Kind regards, Hugh
From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org]
On Behalf Of Cliff Redus via Personal_Submersibles
Sent: Monday, 21 July 2014 1:45 a.m.
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] O2 regulator
Good point about the ABS increasing the CO2 limit for scrubber change out
and emergency lift support situations. I still prefer to have higher
resolution of the measurement for normal operating conditions so I will
stick wit my 1% sensor. If you install a 5% sensor and find out you are not
happy after using it awhile, the nice part about using a PLC is it is easy
to change a few rungs of ladder logic and install a different sensor.
Sounds like you are having second thoughts on casting an aluminum hull. If
you went with ABS rule, you would end up having to do a lot of imperial
testing of the hull meet their classing rules. Thy like and understand
steel weldments!
When I last saw the Q-Sub which was several years ago, it had its
exostructure off. There a lot of systems on the boat. Added systems means
added complexity which means a longer time to sort eve thing out. But "I
agree, when she finally gets commissioned, she will be awesome!
Cliff
From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion
<personal_submersibles at psubs.org>
Sent: Saturday, July 19, 2014 10:59 PM
Subject: Re: [PSUBS-MAILIST] O2 regulator
Hi Cliff,
The graphs on your plc sound a great idea. Good way to monitor things.
With G.L. the accuracy you get on the 0-50,000ppm (5%) unit is fine.
They require an accuracy of + or - 0.001 bar CO2 partial pressure. That is
1000ppm.
ABS does say 0.5% by volume limit, but it lets you go up to 1% during a
scrubber change over,
& 1.5% for emergency life support situations.
I like the 0-50,000 unit for peace of mind, in case you did get in an
emergency situation & the CO2
level went beyond 10,000ppm. On the pdf for the higher range units it says
that the minimum operating
pressure is .950 - 40 bar. So I guess you would need to monitor the cabin
pressure with alarms to ensure you didn't
go below the minimum it functioned at. I couldn't see any pressure operating
range specified with your unit.
I'm not sure where I'm at with the aluminum pressure hull idea. Gas
bubbles formed in the casting process
are hard to control. G.L. doesn't like aluminum as a pressure vessel, & it's
more subject to galvanic corrosion than
steel. Also if I wanted it hard anodized I would have to do it outside N.Z.
as there are no tanks big enough here.
There are ASME rules for cast aluminum pressure vessels, but I haven't got
hold of them yet. (anyone own them??)
Phil made one of his Newt suits out of cast aluminum; so hopefully I can
pick his brains on this in August.
Don't you love the flight down here. Hope you sleep well on planes.
I caught up with Hugh last week & some of the exostructure was off his
Q-sub. When you see it like that you can
appreciate the enormous amount of engineering work gone in to it. I think
Hugh is well & truly over it with all the problems
but it's going to be awesome when he get's it diving.
Have a good trip to OZ.
Alan
From: Cliff Redus via Personal_Submersibles
<personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion
<personal_submersibles at psubs.org>
Sent: Sunday, July 20, 2014 8:57 AM
Subject: Re: [PSUBS-MAILIST] O2 regulator
Alan
>From a Navy document on CO2 they describe the physiological impact of CO2 in
the atmosphere:
2-3% Shortness of breath deep breathing
5% Breathing becomes heavy, sweating, pulse quickens
7.5% Headaches, dizziness, restlessness, breathlessness, increased heart
rate and blood pressure, visual distortion
10% Impaired hearing, nausea, vomiting, loss of consciousness
30% Coma, convulsions, death
A 0-30,000 ppm (3%) or 0-50,000 (5%) sensor is fine but you loss accuracy
when the span increases. These meters are typically +/- 0.5% accuracy based
on the span of the meter. For a 30,000 ppm meter, this gives +/- 150 ppm.
For a 10,000 ppm span, the same 0.5% accuracy meter gives you a +/- 50 ppm
accuracy, or three time the resolution of the measurement. Another reason I
like the 10,000 span is for my boat I am trying to stay within the 0-5000
ppm level set by ABS. Normally this sensor is reading 1000-2000 ppm. The
only time is will run higher is when the CO2 absorbent become saturated and
is no longer pulling CO2 out of air. So if has been 8 plus hours on one
scrubber, I start to get a color change of the absorbent and I see the CO2
ppm level start to continually increase, I know it is time to change the
absorbent. My PLC touch screen has a plotting feature so I have a screen
that shows the CO2 and O2 levels plotted over time. It is pretty easy to
see with the absorbent become saturated.
So the short answer is I like the better accuracy I get over the range I
would expect to see.
I am sorry to miss the convention as well. I was looking forward to hearing
about the progress you have made on your new one atmosphere boat. Are you
still planning on casting the pressure hull?
Next week I will be in your part of the world Australia; not home but close.
No plans to hit New Zealand on this trip. Though I would like to see how
Hugh Fulton is coming along on his QBoat
Cliff
From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion
<personal_submersibles at psubs.org>
Sent: Saturday, July 19, 2014 3:01 PM
Subject: Re: [PSUBS-MAILIST] O2 regulator
That's a great link Cliff, have bookmarked it.
I am wanting something to link to a plc & they have some treat options.
How come you didn't buy a unit with a wider range?
Phil's life support paper is saying we can take 3% for 1 hour, but the
range on the one you bought is 0 to 1%.
Sorry you aren't making it to Bellingham. It was a real treat seeing the R
300
in Florida.
Alan
Sent from my iPad
On 19/07/2014, at 12:25 pm, Cliff Redus via Personal_Submersibles
<personal_submersibles at psubs.org> wrote:
I use a K-30, part number SE-0018 , 0-10,000 ppm (0-1%) CO2 sensor from a
company CO2 meters inc. The cost is $85 and it sends a 0-5 VDC output
sensor.
http://www.co2meter.com/collections/co2-sensors/products/k-30-co2-sensor-mod
ule
Has worked flawlessly.
Cliff
Cliff Redus
Redus Engineering
USA mobile: 830-931-1280
cliffordredus at sbcglobal.com
From: Pete Niedermayr via Personal_Submersibles
<personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion
<personal_submersibles at psubs.org>
Sent: Friday, July 18, 2014 7:05 PM
Subject: Re: [PSUBS-MAILIST] O2 regulator
Cliff, What are you using for a CO2 sensor?
Thanks Pete
--------------------------------------------
On Thu, 7/17/14, Cliff Redus via Personal_Submersibles
<personal_submersibles at psubs.org> wrote:
Subject: Re: [PSUBS-MAILIST] O2 regulator
To: "Personal Submersibles General Discussion"
<personal_submersibles at psubs.org>
Date: Thursday, July 17, 2014, 8:30 AM
Hank
On the R300, I have life support
module I call the AMOC system (Air monitoring and Oxygen
Control). Connected to the box is a 1/4" SS tubing
with Swagelok fittings connected to a O2 supply from an
external 2200 psig O2 bottle. I fill this with welding O2
with a whip. In the AMOC module is a medical pressure
reducing regulator (Hudson model 2000). This regulator
reduces the pressure to around 5 psig. The pressure
downstream of the regulator is adjustable with a maximum
rate of 15 SLPM. The porting on this regulator is two
1/4" NPT HP ports and one LP port. Downstream of
this regulator, I have installed an O2 thermal mass meter/
controller from Porter.
The model number is 201-FSVP. This controller can be set
from 0-10 SLPM via an 0-5V analog input signal. Max
pressure on the O2 controller is 25 psig. This O2
controller also sends out at 0-5V analog output signal of
the O2 SLPM flow rate.
Both these items were purchased on
Ebay at a fraction of list. I have been very happy
with the performance of these units. By measuring the O2
and CO2 percentages in the cabin, I have a PLC that opens
and closes this controller to keep the cabin O2 % between
19-22%. ABS regulations requires that the O2 be held with
in 18-24%. The advantage of this system is that it
automatically accounts for different metabolic consumptions
rates for O2. In the AMOC unit, I have a Swagelok needle
valve in a bypass around this controller so that if both
main and back up power are lost, the pilot can manually
adjust the O2 rate
into the boat.
The
second part to controlling the atmosphere in the cabin is
scrubbing the CO2. I initially used a axial flow filter
with SodaSorb HP. I found that the axial flow filter did
not work very well with CO2 in the cabin ranging from 0-7000
ppm. Part of the problem was the axial filter arrangement
and part of the problem was the blower was not strong
enough. At the 2012 PSUB convention in Vancouver, Alec
Symth brought the scrubber he was using on Snoopy as a
show and tell. His scrubber is an OTS radial filter that
is used to clean air. In 2013, I switch to this type of
scrubber/filer again with SodaSorb HB and the scrubber has
worked much better. It consistently keeps the CO2 level
below 2000 ppm with most of the time it being 1000-1500
ppm. ABS rules require that you keep O2 concentration
below 5000 ppm. Part of the reason that is works better
is the radial design which minimizes the pressure drop
through the Sodasorb and part is that I have switched to a
stronger blower.
Long
answer to short question.
Cliff
On Thursday, July 17, 2014 9:27 AM,
hank pronk via Personal_Submersibles
<personal_submersibles at psubs.org> wrote:
Hi All,I need to find a pediatric
flow meter and regulator for Gamma. Or is there something
better?Hank
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