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I’ve opened and re packed a securus filter and I was unimpressed with the setup the sensor/ metal loop is in the 1st inch of media so it’s only calculating from the 1st 25mm on media where the air begins to enter the filter ending filters life early.
You got the airflow wrong.
It is bottom to top for air purification air flow and the Securus dessicant small bowl or sensor is on top.
It is always this way for the air flow, from bottom of filter tower
13X 1st bed >> 13X 2nd bed>> AC>>13X>> Hopcalite if using hopcalite
SECURUS
13X 1st bed >> 13x 2nd bed >>AC>> 13X >> Securus bowl/sensor/dessicant
Go to page 15
Anyway, Bauer can use resistance to verify how "wet" the securus sensor/desscicant bowl is like how Reverse Osmosis water desalination system can trace "salt" using micro siemens value.
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When the 1st and 2nd bed of 13X is loaded with water moisture at approx -50C dewpoint there about, the securus dessicant bowl/sensor starts to be LESS DRY and can generate signal to its processing unit in the form of those few colors LED. I believed the Securus is -50C dewpoint as max limit of "wetness".
EN12021 breathing air standard calls for very dry air at approx -50C dewpoint or 5C cooler than lowest temperature which the user will be exposed to. However at our regulator 1st stage orifice, the pressure drop from 200 BAR to 9-10 BAR will produce approx -30C of cooling down hence -50C is safe for countries with winter.
Aside from freezing of 1st stage regulator in winter be it for SCUBA or SCBA fire fighter breathing air supply , the hopcalite must be at very DRY condition and -49C dewpoint is believed to be optimal.
This I learnt from Swam Diver who is a Doctor and writer of this : Compressed breathing air the potential for evil from within.
He taught me a lot on how to be able read dry air of -70C dew point. Its not easy, when copper is a WET metal at this dryness level
On the Hopcalite / CO Remover thingy.....
That is why even for me in the tropics, I still use -49C as max wet-ness of my P41 or keep it at EN12021 air standard just in case Mr Murphy wants to ruin me.
If one has a true NIST traceable dewpoint sensor -70C or -80C version, one can learn a lot on what is a DRY AIR and what materials are wet and how storing 13X not in metal cannister is not good thanks I didn’t
Thanks I didn’t realise the air traveled the opposite way in this system, it makes better sense now with the sensor location.You got the airflow wrong.
It is bottom to top for air purification air flow and the Securus dessicant small bowl or sensor is on top.
It is always this way for the air flow, from bottom of filter tower
13X 1st bed >> 13X 2nd bed>> AC>>13X>> Hopcalite if using hopcalite
SECURUS
13X 1st bed >> 13x 2nd bed >>AC>> 13X >> Securus bowl/sensor/dessicant
Go to page 15
Anyway, Bauer can use resistance to verify how "wet" the securus sensor/desscicant bowl is like how Reverse Osmosis water desalination system can trace "salt" using micro siemens value.
========
When the 1st and 2nd bed of 13X is loaded with water moisture at approx -50C dewpoint there about, the securus dessicant bowl/sensor starts to be LESS DRY and can generate signal to its processing unit in the form of those few colors LED. I believed the Securus is -50C dewpoint as max limit of "wetness".
EN12021 breathing air standard calls for very dry air at approx -50C dewpoint or 5C cooler than lowest temperature which the user will be exposed to. However at our regulator 1st stage orifice, the pressure drop from 200 BAR to 9-10 BAR will produce approx -30C of cooling down hence -50C is safe for countries with winter.
Aside from freezing of 1st stage regulator in winter be it for SCUBA or SCBA fire fighter breathing air supply , the hopcalite must be at very DRY condition and -49C dewpoint is believed to be optimal.
This I learnt from Swam Diver who is a Doctor and writer of this : Compressed breathing air the potential for evil from within.
He taught me a lot on how to be able read dry air of -70C dew point. Its not easy, when copper is a WET metal at this dryness level
On the Hopcalite / CO Remover thingy.....
That is why even for me in the tropics, I still use -49C as max wet-ness of my P41 or keep it at EN12021 air standard just in case Mr Murphy wants to ruin me.
If one has a true NIST traceable dewpoint sensor -70C or -80C version, one can learn a lot on what is a DRY AIR and what materials are wet and how storing 13X not in metal cannister is not good .
Thanks for the input you clearly know your stuff, I’m newish to compressors well the filtration side but every day is a school day , thanks once again for taking the time to explainIn a P21 / Zero the air processing flow is from top to bottom, this is because that so called filter housing is a combo unit with water separator.
P41 and bigger is a stand alone filter housing ONLY, so it is from bottom to top air processing flow, which is better as dirt/wetness can be brought down by gravity...well kinda
If a P21 uses bottom to top air flow, its air will be VERY WET as surrounding the exterior of the P21 blue plastic filter cartridge is wet with water condensate of a water separator, which a P21 is also a water separator. So P21 need air to exit at the bottom and directly to the PMV and then filler hose to make sure air is driest.
View attachment 752134
As I said, if funds allows, always use a stand alone filter housing like P41 or bigger and have a stand alone 2nd*/final water separator ( *3 stage compressor ). A P41 has a check valve between final WS to P41 housing, so no cross wet contamination from WS during compressor inactivity.
The air quality of a P21 is so so but can be VERY GOOD for small numbers of tanks if user uses virgin filter cartridge on that very day air fill is done and user is to NOT KEEP the compressor un-used for too long.
If user is a weekend warriors small group with 3,000PSI 80CF 10 tanks only per weekend and dive per every other week, and the ambient temperature is 30C like most tropical location of when in summer in USA hot zones... by the 2nd week or 2nd airfill session, the P21 which technically still have 20 more tanks fill life is no more as good and dry as 2 weeks ago, as water vapor ( liquid water actually ) in the housing willl hit the media. Afterall P21 interior is so wet... what else can we do ?
Above sad truth is from the inferior filter + WS combo housing a P21 is.
The other issue is too short dwell time of the air flowing among the media 13X, AC and hopefully hopcalite in use too. At approx 65-67 grams of 13X a P21 filter cartridge is vs a P41 at 674 grams which is 10 times more just for the 13X and so many times more for the AC and Hopcalite.... a 200L per minute compressor using P21 filter cartridge size will have air flow 10 times faster compared to using a P41 sized filter cartridge. FAST = BAD & SLOW = GOOD.
These 13X and AC media-s are not like say a fuel or oil filter media which is a particulate filter paper able to trap dirt at XYZ sizes. 13X and AC are sieve, a temporary keeper only and not a trapper and slow flow with deep bed depth is very effective for them. Hopcalite is a catalyst, which slow is also good.
These 2 being a molecular sieve, makes them temporary keeper only and once saturated , they will release** all the baddies ( **breakthrough) into your tank in favor of newly incoming water vapor.
This breakthrough is bad and dangerous.
I used to co-own and/or in charge of maintenance and operation of quite a few compressors since the 90s. Capitano 140, Mariner 200 x 2, Junior 100 and PE100. These are from groups of divers who I dive with. I got a few groups I hang out with and we share $$ to buy these. All uses P21, naturally because it is the lowest cost option. I was still "green' back then and mild smelly air as alarm to change filter cartridge is like NORMAL .... LOL
Come 2010 and I done the calculation that a P41 is actually better and cheaper in the long run, so personally a P41 was choosen. I had extensive experience with P61 x 2 towers ( aka P81 ) too in 2011 to 2018 there about.
The air quality of P41 or bigger units is just awesome. Once we get used to this kind of air-quality, anything less will be annoying and for those who does not know, the mild headache at the back of the head you guys get, is not only from carbon dioxide build-up aka over-exertion but less than perfect air is the most common cause. Air does not need to be smelly to be bad at depth, that is the danger.
Allrighty...dive safe.
