Bank size?

[rob.mwpropane]

The only cascade system I am intimate with is the one that used to be owned by the univ that offered the scuba course I took (in 1986). Old, military surplus, water-cooled, 3-stage (IIRC), Worthington compressor connected to six 3,500 psig bottles that he would fill to max fill pressure of ~2,500 psig usually. Although only select TA's (I was one) were permitted to operate the compressor and fill cylinders, scuba students often were in close proximity to the compressor and cascade bottles and fill whips (which were sited in the scuba gear room).

The scuba coach/prof would hydro his bottles quite often, cycling through them every three-five years or so (IIRC).

I don't know if the university's risk management office stipulated this schedule, or if this schedule was due to the coach's own natural risk aversion. (He would often speak of a fill station accident that occurred at a univ in a neighboring state, that maimed or killed someone.)

Note: The above is recalled from ancient memory, so ...

ETA: Just searched and found an old post (Help Settle a Tank Filling Discussion) I made, which is consistent with what I wrote above.

rx7diver

I have never seen a shop hydro after the 1st, but I've also never looked hard enough nor have a ton of experience with LDS's... but the layer of dust I see says a lot, lol.

 

[rjack321]

Does anyone actually hydro bank bottles? Or maybe they hydro once and then forget about it.

I have, I meant they were 15yrs past their last one, I figured someone should peek inside and make sure they were still sound. I sure as hell wasn't going to try and get those valves off.

I have 2x 4500, 2x3500, 3x 2400 = about 2300cf of 32%

 

[MaxBottomtime]

 

[rob.mwpropane]

I have, I meant they were 15yrs past their last one, I figured someone should peek inside and make sure they were still sound. I sure as hell wasn't going to try and get those valves off.

I have 2x 4500, 2x3500, 3x 2400 = about 2300cf of 32%

I currently have 4x3500, 9x4500. Undecided on what format to put them in, but my panel is capable of 4 banks.

I had 4 6000, but sold them. I realized I don't have any need for 6000, nor would I ever take my compressor that high.

 

[sea_ledford]

We have to follow DOT regs for my university program, so all the bank bottles get hydroed on schedule. Actually, they aren't hydroed anymore, they undergo a ultrasonic inspection, which is great because we don't have to drain the tanks, and it costs less!

Ultrasonic Examination (UE) - FIBA Technologies, Inc.

FIBA's ultrasonic examination of high-pressure cylinders & vessels has become the preferred method of requalification throughout the world

www.fibatech.com

not who we use, but they have a video on the process and a pretty good FAQ

 

[rx7diver]

We have to follow DOT regs for my university program, so all the bank bottles get hydroed on schedule. Actually, they aren't hydroed anymore, they undergo a ultrasonic inspection, which is great because we don't have to drain the tanks, and it costs less!

Ultrasonic Examination (UE) - FIBA Technologies, Inc.

FIBA's ultrasonic examination of high-pressure cylinders & vessels has become the preferred method of requalification throughout the world

www.fibatech.com

not who we use, but they have a video on the process and a pretty good FAQ

Interesting. So, no peeking inside the bottles (no VIP)? If moisture gets by the oil/water separators and filters and into the cascade cylinders, what then?

And what about checking the bottles' valve threads?

rx7diver

 

[rjack321]

Interesting. So, no peeking inside the bottles (no VIP)? If moisture gets by the oil/water separators and filters and into the cascade cylinders, what then?

rx7diver

Wait for them to pit in 20 years?

 

[Tracy]

Interesting. So, no peeking inside the bottles (no VIP)? If moisture gets by the oil/water separators and filters and into the cascade cylinders, what then?

And what about checking the bottles' valve threads?

rx7diver

What difference would it make? The UE examines the bottles integrity, if whatever you put in it doesn't affect the integrity of the tank, it it doesn't matter.
Why would you need to check threads that haven't been disturbed? They were fine when it was assembled, they didn't go out of spec sitting in place with a valve installed.

 

[sea_ledford]

Interesting. So, no peeking inside the bottles (no VIP)? If moisture gets by the oil/water separators and filters and into the cascade cylinders, what then?

And what about checking the bottles' valve threads?

rx7diver

From the FAQ:

Isn't the internal visual inspection important to find contaminants and oil in the cylinder?​

No. If a cylinder is suspected of having been contaminated you must either test the gas for the suspected contaminant or pull the valve and examine the cylinder. You should not wait for the next requalification. Note that just because you need not devalve and internally inspect a cylinder for UE, nothing prevents you from doing such a procedure if your policy requires it. We highly recommend removal of any valves that are suspect to internal cylinder contamination.

Why aren’t the necks and bottoms checked during the UE requalification process?​

Because of the design of 3A, 3AA and 3AL cylinders, the shoulder and bottom are low stress areas, with thicker material. The cylinder is examined from the transition area down through the knuckle radius.

 

[rx7diver]

What difference would it make? The UE examines the bottles integrity, if whatever you put in it doesn't affect the integrity of the tank, it it doesn't matter.
Why would you need to check threads that haven't been disturbed? They were fine when it was assembled, they didn't go out of spec sitting in place with a valve installed.

I am not an engineer. I don't really know how this type of thing works. However, I have heard of scuba cylinders being condemned during a new inspection because of issues with their threads. How did this thread "damage" happen, I wonder?

rx7diver