Mailing List Archive

Mailing List: cavers

Banner Advert

Message Display

From: "David Dalton" <david_dalton@ho*.co*>
To: phi@sk*.be*, david_dalton@ho*.co*, Bakalite@ba*.co*,
     dmdalton@qu*.ne*, Art.Paltz@R2*.CO*, techdiver@aq*.co*,
     cavers@cavers.com
Subject: RE: "OMS Like" DIN flow regulator
Date: Wed, 16 Aug 2000 17:33:33 GMT
Dear Phi,

You wrote:
>Dear Dave,
>
>Don't get offended!

I'm not offended just mildly annoyed.

>1. Yes, I did try to make a point.
>    (copying Jeff Bentley's style without success, I must add)

Free advice (which is worth just what you pay for it) "A copy is rarely as 
good as the original."

>2. Yes, I don't have the Handi but think having 2-digit is fine.

Thank you for your opinion. Mine would be that it might be fine but if I can 
get something that is more accurate for less money in both the short term 
and the long term that makes more sense.

>3. All.

Thank you for your opinions.

>4. Yes. Because I built mine. They work fine.

I guess you meant yes you use an analyzer, while what I was trying to ask 
was "Do you use a Handi." I wasn't clear in my question? What you are saying 
is that you have chosen not to/or don't use a Handi.

>Think about this for a minute... Assuming you want max PO2 of 1.2, 11.5%
>would let you go down to 94m (308ft). If you have 12.5%, PPO2 at 94m would
>be 1.3
>
>Is it a big deal ? I don't think it is, and it would be even less important
>when you mix higher O2% for Nitrox and deco gas.

I've got no problem with this other than you could have said it in your 
first post instead of what you did.

>They were rhetorical questions as I knew the sensor accuracy. All of them
>are about 2-3% off *full-scale*. Do you understand what that mean ? :-)
>
>I used to use the voltmeter/calculator method for a long while and it is
>fine even now. The only reason I built the meters was the chance to learn
>some electronics.

Yes, I understand. I knew the electronics, I built mine because I could and 
to limit equipment/procedures at the dive site.

>I don't mix even 1/100th of the amount the WKPP guys do, but enough to not
>worry about the decimal places on my trimix. If you use a good pressure
>gauge and correct fill rate, you shouldn't be surprised when reading your
>analyzer.
>This reminds me of people who PP blend to the exact single-digit, or deco 
>to
>the exact second, or uses Helium analyzer...

You seem to be jumping to the conclusion that because I would choose to buy 
a piece of equipment that has a greater accuracy level while costing less, 
then I must have a Helium analyzer, mix to the nearest 100th of a percent 
and deco to the exact second. You are wrong.

I take care in what I do but am not paranoid. Again, if I can get something 
that is more accurate & it cost less why wouldn't you do that. You and I 
both did. If someone else wants to use a Handi they are free to do so. What 
this came out of was my clarification to Paul (who commented that a boat he 
had been on, had less than positive experiences with the Handi) that I was 
misunderstood and was not recommending the Handi, but rather the company's 
BC adapter to regulate flow.

>I wasn't really trying to pick a fight with you, but now you sound pretty
>obnoxious :-)

Then I misunderstood your tone and intent. You are certainly entitled to 
your opinion, but please note: "Opinions are like armpits, everyone has a 
couple and they all stink."

My opinion would be: "You are not without value. You can always serve as a 
bad example."

Dave Dalton


>-----Original Message-----
>From: David Dalton [mailto:david_dalton@ho*.co*]
>Sent: Wednesday, August 16, 2000 3:40 PM
>To: phi@sk*.be*; david_dalton@ho*.co*; Bakalite@ba*.co*;
>dmdalton@qu*.ne*; Art.Paltz@R2*.CO*; techdiver@aq*.co*;
>cavers@cavers.com
>Subject: RE: "OMS Like" DIN flow regulator
>
>
>"Phi Le" wrote:
>
> >Dave,
> >
> >Assuming this is 2-digit and no decimal places, that should cover the 
>range
> >from 00 to 99 for O2.
> >
> >How accurate do you need your mix to be ? And do you know how accurate 
>your
> >sensor is ? :-)
> >
> >-Phi
>
>
>Dear Phi,
>
>A few questions and then the answers you asked for:
>
>If I misunderstood your tone/intent my appologies but
>
>Did you have a point you were trying to make?
>Do you think the Handi is a suitable unit for all O2 analyzing tasks?
>If not all, which ones do you think it is good for?
>Do you use one? Why did you decide on it? How has it worked out for you?
>
>Your questions seem to want to start an argument as opposed to seeking
>knowledge. 2 minutes on their web site would have told you the acuracy of
>the Handi & the MAX 250-E.
>
>
>The following are the reasons I chose not to use a Handi O2 analyzer:
>
>1 ) In-my-never-to-be-humble-opinion 2 digit display is fine for
>recreational nitrox. For a low O2% trimix it might not be. As I am just
>starting to mix I would say others (George, JJ, Jess, Scott) on these list
>could address the usefulness of this unit in those applications far better
>than I, and I defer to them.
>
>2) A 2 digit display could introduce an additional error of as much as 1%
>(11.5%-12.5% displayed as 12%, you wanted 11.5%, you tested and got 12% so
>you think you are close but you really got 12.5% so you are off by 1.0%
>rather than 0.5%).
>
>3) The unit itself is accurate +/- 3% full scale over operational
>temperature range (as listed on their site)
>
>4) The MAX 250 E is accurate +/- 2% of full scale (as listed on thier site)
>
>5) Combining 2 & 3 above I would deduce that you are looking at a unit to
>unit accuracy level of 2% vs 4%.
>
>6) The Handi cost about $230 with the fittings that started this thread.
>
>7) I just built my own and it cost $136.50 including the sensor + fittings 
>-
>Oh, I almost forgot I bought my computer geek a Mountain Dew @ $1.04 to
>modify the panel meter for me - at 52 the eyes don't like close work and 
>the
>hands are no longer suitable for conducting brain surgery.
>
>8) In 2 to 4 years when my sensor "cashes in it's chips" it will cost me 
>$65
>for a new one instead of $200 for a new Handi-dandy (and I hate throwing
>away the "car just because it needs new sparkplugs").
>
>9) If I was as cheap as MOST divers, I could have just used my Radio Shack
>Digital Multi Meter (which I bought for $39.95 a number of years ago) and a
>$5 calculator in concert with the MAX 250. That way my expenditures would
>have only been about $95 for the MAX 250 and fittings or $65 if I skipped
>the fittings.
>
>Please excuse any errors. I am new to diving, I didn't start until 1962 
>:-).
>
>Dave Dalton
>
>
>
> >
> >-----Original Message-----
> >From: David Dalton [mailto:david_dalton@ho*.co*]
> >Sent: Tuesday, August 15, 2000 5:52 PM
> >To: Bakalite@ba*.co*; dmdalton@qu*.ne*; Art.Paltz@R2*.CO*;
> >techdiver@aq*.co*; cavers@cavers.com
> >Subject: Re: "OMS Like" DIN flow regulator
> >
> >
> >Paul,
> >
> >I guess I was unclear in what I posted. I wouldn't recommend the Handi
> >analyzer, since it's use is limited with only a 2 digit display, but 
>their
> >BC adapter and barbed adapter will work with their medical & industrial
> >sensors such as the MAX 250E.
> >
> >Dave
> >
>
>________________________________________________________________________
>Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
>
>
>

________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]