realdiver7
Contributor
I have an Alkin W31 3.5 cfm compressor with manual drains, moisture monitor, carbon monoxide monitor and Nitrox stick for continuous blending. I just started pumping my own air this summer and really enjoy the convenience of doing it myself. The Alkin is a great compressor and I have no complaints about it. Continuous blending is easy once you get the hang of it, follow instructions and pay attention at all times.
When I fill my steel 77s, steel 100s and aluminum 80s, I notice that the tanks (cylinders) heat up very quickly regardless of whether I'm filling Nitrox or just air, especially as they get more and more full. I expect a certain amount of heat from them, but have been wondering how hot they are actually supposed to get when being filled at such a slow rate. I usually alternate between them, filling each one partially, and then returning to top them off, but that seems like a lot of trouble and fast work before the over pressure relief valve pops.
When I say hot, I mean the tanks get very hot, especially around 2,000 psi, but not so hot that I cannot touch them. I can hold them firmly with the palms of my hands and not feel like I'm getting burned, BUT they still seem to be much hotter than what I have been used to getting back from the dive shop.
Questions....how hot can they get without having expansion and contraction problems that could result in bad hydros over time, or without having some sort of catastrophic wall failure? Any ideas on other methods used to fill them like closing the whip valve partially to slow down the flow, or is this bad for the valve? How do you personally determine how hot is too hot for your tanks?
Edited to add: I fill my tanks directly from the compressor and do not use a cascade system as I normally fill only about 4 tanks each weekend. Tanks are filled dry; not in a tub of water.
Thanks!
When I fill my steel 77s, steel 100s and aluminum 80s, I notice that the tanks (cylinders) heat up very quickly regardless of whether I'm filling Nitrox or just air, especially as they get more and more full. I expect a certain amount of heat from them, but have been wondering how hot they are actually supposed to get when being filled at such a slow rate. I usually alternate between them, filling each one partially, and then returning to top them off, but that seems like a lot of trouble and fast work before the over pressure relief valve pops.
When I say hot, I mean the tanks get very hot, especially around 2,000 psi, but not so hot that I cannot touch them. I can hold them firmly with the palms of my hands and not feel like I'm getting burned, BUT they still seem to be much hotter than what I have been used to getting back from the dive shop.
Questions....how hot can they get without having expansion and contraction problems that could result in bad hydros over time, or without having some sort of catastrophic wall failure? Any ideas on other methods used to fill them like closing the whip valve partially to slow down the flow, or is this bad for the valve? How do you personally determine how hot is too hot for your tanks?
Edited to add: I fill my tanks directly from the compressor and do not use a cascade system as I normally fill only about 4 tanks each weekend. Tanks are filled dry; not in a tub of water.
Thanks!
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