Honest Phil?

[MSilvia]

I just ran across a page advertising a temperature sensitive sticker designed to encourage shops to give slower (and therefore fuller) fills. It supposedly tells you how much pressure you stand to lose when the tank cools to 70f.

Has anyone tried one of these things? If so, are they worth using?

I'm about done with novelty dive gizmos, but this seemed kinda cool.

http://www.honestphil.net/

 

[Uncle Pug]

I have one on the first tank in my bank and it seems to give a fairly accurate read of the *shrinkage* to expect. I have several others to attach to dive cylinders but have not done so yet.

BTW... Honest Phil is a member of Scuba Board!

 

[DiverBuoy]

Honest Phil's™ pressure drop indications are valid only at time of air fill.

nah really ... we were thinking we could save money on a console <LOL>

 

[jepuskar]

Sometimes after entering the water I wish I had something to measure the 'shrinkage'.

 

[Dectek]

How accurate will it be if a tank is being filled while sitting in a dunk tank? Doesn't the abmient water temp affect the tempature sensitive strips on the sticker? The way I see it .... the tank is warming the sticker from the back and the water is cooling it from the front.:drown:

 

[Uncle Pug]

Dectek once bubbled...
How accurate will it be if a tank is being filled while sitting in a dunk tank?

and I don't know the answer... since I haven't put any on my dive tanks... but when I do I will report here...

However if the idea is to get slower/better fills at the LDS then putting them in the water tank should help from that standpoint... and maybe the Honest Phil would motivate them to do that from the beginning of the fill.

I know guys who are always getting short fills because the LDS only puts the diver's tanks into the water for the last boost up to full pressure.

They say that it makes no difference putting the tanks in water... and maybe it doesn't if they are jamming the jugs in minutes dry and only putting them in after they are heated up.

When I fill LP104s dry they shrink by 300psi... and when I put them in the water tank they don't shrink at all.

So back to your question... I suspect (but don't know for sure) that it would depend upon when the tanks were put into the water tank.

 

[Genesis]

and you won't have that problem.

200-300 psi/minute is a good maximum rate.

The entire problem comes from blasting air into tanks way too fast, which is a bad idea anyway.

Water-bath fills have their own set of problems. While steel tanks might be helped by a water bath fill, aluminum ones almost certainly are not (the walls are MUCH thicker, and thermal mass gets you on this one.) It also opens up the possibility of water getting into the tank, which is very bad.

 

[Uncle Pug]

Genesis once bubbled...
It also opens up the possibility of water getting into the tank, which is very bad.

That's why I hate taking my tanks diving... I mean they might get water in them.

Come on Genesis... done right there is no possibility of getting water in the tank.

You open the valve and blow some gas out... you close the valve... you attach the fill whip... you open the valve... you put the tank into the water.

Why it's almost like what you do setting a tank up for diving!!!

 

[Big-t-2538]

Uncle Pug once bubbled...

They say that it makes no difference putting the tanks in water... and maybe it doesn't if they are jamming the jugs in minutes dry and only putting them in after they are heated up.

When I fill LP104s dry they shrink by 300psi... and when I put them in the water tank they don't shrink at all.

So back to your question... I suspect (but don't know for sure) that it would depend upon when the tanks were put into the water tank.

In order for water to do an effective job cooling the tank, it would have to be constantly moving around the tank...much like the coolant around the engine in your car. IF it isn't moving, the water almost acts like an insulator around the tank becasue the coolor molecules aren't mixing with the warmer ones next to the tank.

Thus a water tank makes an almost negligible difference unless it is circulating in some fashion

Genesis once bubbled...

Water-bath fills have their own set of problems.......It also opens up the possibility of water getting into the tank, which is very bad.

Please...who in the world is filling your tanks...stop paying that guy/monkey

-TT

 

[scuberd]

I heard during my fill-station training that someone did the thermal-dynamics of filling tanks and the water would have to be almost freezing in order for it to make much of a difference, (when filled properly.)