understanding Moisture water cycle in tank

[JointVentureDive]

Grumpie
Do the tanks that you fill at the various fire houses have heat dried compressed air, that you supply the Henn. Cty dive team with? 

The reason I ask this, is not only for the integrity of the tank, but the real potential for FREE FLOWS through the reg. if the diver took some breaths on the surface in sub freezing air temps. etc.

One thought might be that if you do not have heat dried air in the process, that you may be potentially adding a technical problem to those divers  that they really should not be subjected to if they had to make a ice or cold water winter rescue to. 
thanks in advance for your help.
nik

[leadking]

Dryers do not heat the air, they cool it! Hot/warm air holds more moisture than cold air.

[LRRP02]

Places that are filling air should be doing air checks with one of the companies like Trace  Ask for their air report most places display them on that report it will give you the needed info I know some of them have air so dry that the freeze up point is like 90 below F and if it is less than 60 below F they require a retest in order to pass the test. I know a couple of shops that don't do this and are pumping air in their building which has steam heat and at this time of the year they have moisture problem. I have seen it in the tanks and rescue squad that was getting air from them experienced a lot of free flows

[JointVentureDive]

Hi Lee, and LLRPT
Thanks for your input.  Lee, I really meant to say what you said.  As you may know, I meant to say dry the air, but then I had a brain. F.... and suggested that it heats the air.  The reason I made the mistake is... I associated the heat that is given off by the driers, to the room area wherever the driers are located by the compressors, with the drying process as I really do know it cools it down to take the moisture out. 

I know the moisture is collected and discharged somehow, but I am not sure about that part.  Lee, I know you've made a career with the tanks, how does the moisture get collected and discharged from the line.  (I know how my ........ is discharged.. nevermind you guys  )

Anyway, my point  I was trying to make with Grumpie, was exactly what LLRPT said happens. 

The reason I brought this up in the first place,  was I either read  or heard that Grumpie fills the tanks for the Sheriffs Dept at several different fire stations, and I'm pretty sure due to the nature of they're fill stations and above ground air requirements, they are not as concearned as divers would be, with the moisture content in they're breathing aparathus.
So, I was merely inquiring as to wether or not they use driers to reduce moisture content.

LLRPT  do you care to share the name of the dept.  This could be what they're problem is.  Of course it is probably why they were having so many free flows. That too sounds like a possible accident waiting to happen.

Nicky

[popolarbear]

sorry, part of the link i pasted didnt copy, here it is...



"  Understanding Dew Point & ppm moisture

This topic is very complex; we will discuss just the basic parts.  The term Dew Point is the temperature at which the gas can no longer hold the moisture in the evaporated state, but causes it to spontaneously condense onto surfaces or remains suspended as micro droplets. Moisture is expressed in three ways: Dew point (in degrees Fahrenheit or Celsius ),  parts per million by volume (ppmv) and mg/cubic meter.

If you have air that has a dew point of -64ºF at one atmosphere pressure, the water content will be 24ppmv, and the air is considered dry.  If you then charge a SCUBA tank to 3100psig with that same air, the moisture content will still be 24 ppmv, but because the water and air molecules are now compressed together, it is easier for the water molecules to "stick" together and  condense onto the cylinder walls.  If you measure the dew point of the air in that cylinder at the 3100 psi pressure, you would discover that the dew point inside the cylinder is now +28 ºF (that dew point is called the Pressure Dew Point).  That means that if the outside temperature becomes colder than +28ºF, the compressed air in the cylinder will condense onto the SCUBA flasks interior walls. "




very interesting subject.

[grumpie]

Dont really understand why you are trying to make a point with me. My air is grade E and its tested every year at the same time that my compresser is serviced, oil changed. I change my air filters on a regular hourly time. Whats the point?

[popolarbear]

I'm not singling you out, or attempting to cause any ripples, this is just a intellectual understanding thats it. it is very interesting, as since i came upon this understanding, i know some of my acquaintances who are storing tanks in unheated garages that probably have frozen ice on the insides of the tanks based on these physical laws. although at these temps the reaction of frozen water, 02 and metal may be slow enough that it doesn't cause much damage.

[grumpie]

not picking on you poplar bear, its the Young lady

[JointVentureDive]

Grumpie,
At least you admit that.   

Actually, I was told that you have filled air tanks for the sheriffs dept. at various fire dept houses within Henn. Cty.  I was told you even have keys for the fire houses. So, my only questions was that of an intellectual one is, as we all know, the quality of air / moisture content is not as critical to the firemen, as it is for scuba divers.

Of course I know the air is filtered etc, and I certainly would not try to "pick an argument with anyone"  just trying to have a discussion about humidity in the air. 

say your sorry, and lets move forward.   Just answer the question,

If it is true what I said above, perhaps, it would be wise to consider the standards and practices that the LLRP has suggested.

Its just about a little thing called added safety, and reducing by a smiggen a chance of free flows.  Especially, since any rescue diver in a rescue situation as opposed to a recovery situation would be breathing somewhat faster then his or her normal dive.

I know many of the best shops are drying the air that they fill in our tanks.  The subject was moisture in the tanks.  Even some shops in Fl are drying the air. 
Nicky