Booster Solution - Need your input
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it depends on supply pressure. The booster is going to use 5-10:1 ish drive gas depending on the supply pressure. You're trying to move 60cf of gas, so 300-600cf of drive gas required. More for less supply pressure. Best case? 300cf/3cfm=100mins. Worst case? 600cf/2cfm=300mins
Three thoughts...
1) I found a used AG-30 Haskel for $500, and even with new seal kits and new build fill whips I only have about $1000 in it. That compares to about $3k for a rebuilt AG-30 or $4300 for a new one. There are deals out there, you just have to know where to look and know how to do a basic rebuild.
2) I run my AG-30 of a 5 cfm compressor with a 26 gallon tank. It's also quiet, at 80 dB from 2 feet away. It's advertised as 70 dB but I have to get 12' away inside my garage to get a reading that low. I suspect they are measuring in a large open space and/or from some distance away to get a 70 dB number. However, it's quiet enough that I can't hear it running in the garage from inside the house with the door closed.
https://www.lowes.com/pd/Kobalt-QUI...tric-Vertical-Quiet-Air-Compressor/1000405189
It will maintain 90-100 psi with about one cycle every 5-6 seconds. That's about perfect for 02. At a 2800 psi supply pressure it will push about 0.4 cf per cycle (about 4-5 cfm per minute), but that will drop off as the supply pressure drops.
3) if you are using shop air, it's worth your time to try to clean it up. I use an oil-less compressor and then run the air through a 50 foot hose submerged in a 5 gallon bucket of water (I route the hose through two 3/4" holes in the lid it minimize evaporation). The water cools the air and lets the moisture in it condense out. I then run it through a water separator to remove the water, and then run it through a desiccant filter to remove any remaining water. My compressor has 2 outlets so the shop air goes through a separate hose, while the clean air goes through the condenser and desiccant. Clean, dry, oil free air will keep the drive section of a Haskel much cleaner.
1) I found a used AG-30 Haskel for $500, and even with new seal kits and new build fill whips I only have about $1000 in it. That compares to about $3k for a rebuilt AG-30 or $4300 for a new one. There are deals out there, you just have to know where to look and know how to do a basic rebuild.
2) I run my AG-30 of a 5 cfm compressor with a 26 gallon tank. It's also quiet, at 80 dB from 2 feet away. It's advertised as 70 dB but I have to get 12' away inside my garage to get a reading that low. I suspect they are measuring in a large open space and/or from some distance away to get a 70 dB number. However, it's quiet enough that I can't hear it running in the garage from inside the house with the door closed.
https://www.lowes.com/pd/Kobalt-QUI...tric-Vertical-Quiet-Air-Compressor/1000405189
It will maintain 90-100 psi with about one cycle every 5-6 seconds. That's about perfect for 02. At a 2800 psi supply pressure it will push about 0.4 cf per cycle (about 4-5 cfm per minute), but that will drop off as the supply pressure drops.
3) if you are using shop air, it's worth your time to try to clean it up. I use an oil-less compressor and then run the air through a 50 foot hose submerged in a 5 gallon bucket of water (I route the hose through two 3/4" holes in the lid it minimize evaporation). The water cools the air and lets the moisture in it condense out. I then run it through a water separator to remove the water, and then run it through a desiccant filter to remove any remaining water. My compressor has 2 outlets so the shop air goes through a separate hose, while the clean air goes through the condenser and desiccant. Clean, dry, oil free air will keep the drive section of a Haskel much cleaner.
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Many diving air compressors will handle helium ok, but be aware that they run a lot hotter when compressing helium. It can be an issue when continuous blending trimix on a hot day, particularly, if the intercooling between stages is minimal. If you are compressing 100% helium it's almost certainly going to be an issue.
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This has not been my experience. Can pump 100% helium through my oil lubed alkins at 2000psi and the heads are cooler (on a laser thermometer) than air or 32% pumped. I cant do it for very long (~30mins is my max) as the oil gets foamy over time. Above 2500psi the blowby on the third stage is getting excessive. But for topping up a set of doubles or CCR bottles, its easy to scavange 100% helium this way. Oxyhacker call this the "trash bag" booster method in his book.
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