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As you stated the cells don't last forever. but you can extend their life by putting a piece of Saran (SP?)Wrap (the stuff you used to wrap sandwiches in BEFORE they invented Glad bags but AFTER wax paper went out of style) and put it in a small container like a pill bottle and store it in the fridge. About 10 years ago I learned more about these than I wanted too while dealing with my youngest son who was ventilator dependant & on suplimental oxygen. Standard medical protocol when setting up the analyzer to adjust the paitent's O2 level, was to test it against pure O2. If you can adjust your analyzer to read 100% or more on pure O2 then the sensor is still good. If it will only read 80-90% it is on the way out but I would still be comfortable using it (after setting it to 20.9% on air) for testing something in the 20-50% range on TAHT DAY. That loss of performance signals the need to order a new one before your next mix/analying session because in a week it might not get higher than a 20% reading on pure O2. This assumes that your unit has the range to read 100% or better when the sensor is fresh. Dave Dalton Last Stanza of the Star Spangled Banner "Oh thus be it e'er when free men shall stand Between their lov'd homes and war's desolation! Blest with vict'ry and peace, may the heav'n rescued land Praise the Pow'r that has made and presrv'd us a nation And conquer we must when our cause is just And this be our motto: "In God is our trust." And the Star-Spangled Banner in triumph shall wave O'er the land of the free and the home of the brave." ----- Original Message ----- From: <Art.Paltz@R2*.CO*> To: <techdiver@aquanaut.com> Sent: Tuesday, October 23, 2001 4:53 PM Subject: RE: O2 Analyzer > Patrick, > > I think we are saying basically the same thing. I've never owned an OMS O2 > analyzer but a friend said that the OMS brochure said the sensor lasted > forever, that is what I was referring to. I guess it's a justification for > the high price. I think their sensor has a little holder that seals the > sensor head. If I was given bad information I apologize. I too think its > BS that a sensor never goes bad. This isn't Star Trek, fuel cells don't > last forever or recharge themselves all by themselves.... :) > > The "Spectrum Oxygen Analyzer" I gave the Web site for > (http://www.oxygenanalyzer.com/) uses as standard the MSA 406931 30 second > sensor (replacement cost $49) and for $10 more will send the Teledyne R-17A > 10 second sensor (you guessed it, replacement cost $59). I think these > sensors are extremely competitive. I'm pretty sure that if you for whatever > reason liked another sensor better you could configure the unit to use that > type. If you need/want that you can contact them directly (they are nice > people), I know they also use the Maxtec sensor. > > My sensor is 3 years old and I'm going to replace it next year. Don't want > to go to analyze tanks and have it dead. Better save than sorry, $49 every > 3 years isn't going to break my bank regardless if the sensor is going or > not. > > Art. > > > -----Original Message----- > From: Patrick Duffy [mailto:pduffyca@ea*.ne*] > Sent: Tuesday, October 23, 2001 12:45 PM > To: Paltz, Art > Cc: rmmacleod@ac*.ca*; techdiver@aquanaut.com > Subject: Re: O2 Analyzer > > Art, > > All O2 analyzers perform the same function and most all have similar (and > often > identical) components. Usually the higher end units have sealed > potentiometers, > on/off switches and electronics enclosures and have a more expensive panel > meter. > > One question often over looked is the cost of a replacement sensor. A > number of > manufacturers have chosen to use a high output sensor in their designs which > results in a more expensive sensor. Others even go as far as making a > proprietary sensor shell to force you to buy their sensor at inflated > prices. > Then there are the mfgs that put the least expensive sensor in the unit in > an > effort to keep the total price of the analyzer down. Some sensors do have a > shorter life than others (read the specs if they will tell you the sensor > mfg) > as well as different response times. I've even seen dive equipment > manufacturers state the sensor will last longer than the sensor manufacturer > claims it will (figure that one out). There are many sensor manufacturers > out > there, making a sensor is not too hard, making a sensor that is consistent > in > performance is the difficult part. I've never heard of a sensor lasting > forever, they are basically batteries that produce mv based on the amount > oxygen > exposure. The greater the PPO2 and length of exposure, the shorter the life > will be. > > Replacing a sensor in an oxygen analyzer is not needed until it is dead. In > most cases you'll be able to calibrate it today, but will not tomorrow. The > only divers that should seriously consider scheduled replacement are those > diving rebreathers. > > Putting the analyzer and sensor in a box is wise for protection, but it will > not > extend the sensor life ... too much space. Along the subject of placing > caps on > the sensor, they cut off the amount of oxygen and do drop the mv > significantly. > I placed a cap over a new sensor I am testing the other day. The sensor was > measured at 10.4mv. I placed a cap on the sensor and over a 4 day period > the > sensor mv dropped until it reached 1.4mv. At that time, I took off the cap > to > see how fast the sensor would recover ... it came back to 10.3mv in about > three > seconds. I checked it about 20 minutes later and it was back to 10.4mv. > This > is a new sensor that is not presently available, and I know not every sensor > make will have this response/recovery time. Most require much more recovery > time. > > Regards, > > Patrick > -- > OxyCheq ... the diver's source for oxygen sensors > http://oxycheq.com > > > > Art.Paltz@R2*.CO* wrote: > > > I bought from http://www.oxygenanalyzer.com/ > > > > In my opinion they are all pretty much the same except for the price. If > > you think about it, all it is, is a panel meter (volt meter) and an O2 > > sensor. As far as I know all panel meters are pretty much the same in the > > range we are talking (1-2%). If we were measuring where millionths of a > > volt mattered then there would be a difference. I don't know for sure but > > even a one percent reading for the oxygen content is only like a millivolt > > and I don't think that's too hard to read for most volt meters. You're > > variance is really going to be in the sensor which if you read the specs > is > > pretty much a percent or 2. I don't know the difference in the sensors, > > you'd have to ask someone else but again, for our purpose, they are all > > pretty much the same as long as kept relatively fresh. You should be > > selecting an O2 content (Po2) that is not going to kill you and is way in > > the save zone. If you are pushing really hot bottom or decompression > mixes > > then you probably should be changing the sensor all the time as they do > > degrade over time (should you choose to be this dumb). If you have some > > reason that I can't really think of where you need to use these type of > > mixes you might want to invest in a spectrum analyzer cause being > extremely > > accurate probably matters. > > > > The one at the above site is pretty much the same thing as the one you can > > build in the O2 hackers handbook. If you are like me and bought all the > > parts (minus sensor) to build one yourself but are too lazy to do it, then > > this is a good deal for you. > > > > I wouldn't believe the claims of sensors lasting forever on some > analyzers. > > They all go! It's just that I think some of them have a cap to cap off > the > > sensor when not in use so it stops degrading until the next use. You can > do > > this yourself by putting the analyzer and sensor in an air tight pelican > > box.... A lot cheaper and you should probably have the analyzer/sensor in > a > > box anyway so it's doesn't break it..... > > > > Just my opinion, hope it helps. > > Art. > > > > -----Original Message----- > > From: The McLeods [mailto:rmmacleod@ac*.ca*] > > Sent: Sunday, October 21, 2001 8:16 PM > > To: techdiver > > Subject: O2 anylizer > > > > Hi list,I'm looking to buy a new O2 anylizer.I'd like some opinions on > which > > one is best,best buy,best made ect.Are all the makes available in > Canada,how > > much are replacement sensor's and what are the best features.Thank's in > > advance,Randy > > > > -- > > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > -- > > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > -- > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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