[PSUBS-MAILIST] O2 regulator

Sat Jul 19 16:57:37 EDT 2014

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-module
> 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
>_______________________________________________
>Personal_Submersibles mailing list
>Personal_Submersibles at psubs.org
>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
>
>  
>    
>-----Inline Attachment Follows-----
>
>
>_______________________________________________
>Personal_Submersibles mailing list
>Personal_Submersibles at psubs.org
>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
>
>_______________________________________________
>Personal_Submersibles mailing list
>Personal_Submersibles at psubs.org
>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
>   
_______________________________________________
>Personal_Submersibles mailing list
>Personal_Submersibles at psubs.org
>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>

_______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20140719/02a1061e/attachment-0001.html>