[PSUBS-MAILIST] O2 regulator

Thu Jul 17 17:47:06 EDT 2014

Alec,
Thanks'
I just  did an experiment based on Cliff's comments.  I doubled the fans on my scrubber.  I put two together and did a test.  With one fan the output is 48ppm CO2 with two fans the output is 18ppm CO2.
Clearly when I changed fans, it lost efficiency.  
I want to keep my scrubber because it can take granular absorbent or cartridges.  I will test both for a cost comparison.
Hank 

On Thursday, July 17, 2014 5:33:10 PM, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Hi Hank,

There really isn't a brand and part number, because its something I got off eBay that was I think made by some enterprising individual. You will find them there in a variety of sizes. Caution, they won't work quite off the shelf. The value was in the two spun ends, which would be relatively hard to make. The cylinders have holes that are way too big for CO2 absorbent. I lined them with much finer mesh, stitching the two materials together with fine wire. 

This is a much more sophisticated solution: http://www.psubs.org/projects/1234567810/printedscrubber/

Best,

Alec

On Thu, Jul 17, 2014 at 11:59 AM, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Alec,
>Reading this, do you have any details of your OTS radial filter that Cliff mentions? 
>Thanks
>James
>
>
>
>On 17 July 2014 16:30, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>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
>>
>>
>>
>>
>> 
>>
>>
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>>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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> 
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