Setting Up Cascade

[rob.mwpropane]

The real question is can your compressor handle that much volume.

I really don't know. It's a Rix SA6. In the winter it might run once a month. In the summer it might run twice a month. Last year was more than usual because we had OW class with the kids.. I'm not even sure which of them want to dive often. I won't force them, it was just something for the brothers to all experience together.

There's usually 4 of us that go diving, sometimes 5. Only 3 days last year was it all 7.

My hope is to run the compressor for 30-45 min a day until the bank is full, and then just periodically. I "hope" it lasts for a long time, I "hope" nothing breaks just like every other compressor owner

 

[RickyVR]

You have a drawing of what you mean?

Hopefully you can see enough detail on this picture. If you notice there is a loop plumped to the very end of the valves in a circle starting at the upper right going counter clockwise downward and then up ending at the upper left bottle. There is a fitting (it has a cap on it currently) which is the highest part of the picture where the air comes in from the compressor. As the air moves from bottle to bottle the air goes through 1 way valves which can be seen in the picture. The on way valves allow the air to enter into the bottle and then can not come back out the way the air entered. Air goes in on this loop but does not come out.
Let's say bottle #1 has 1000psi and bottle #2 has 1500psi and Bottle #3 has 2000psi and bottle #4 has 2500psi and bottle #5 has 3000psi and bottle #6 has 3500psi. This is all possible because the 1 way valves wont' let the bottles equalize to the average pressure of all bottles together. This is beneficial as it keeps topping pressure for filling scuba tanks. When the compressor is started it will fill bottle #1 pushing air in until the bottle has more 1500+psi in it. At that point it will start filling bottle #2 as well as bottle #1. When the pressure exceeds 2000psi the first 3 bottles will be filling. The process continues adding bottles 4,5,6 as the pressure continues to increase past each bottles current pressure. You will notice a 2nd loop plumbed into the side of each bottles valve with and on/off valve plumbed for each bottle. The process of filling would be to connect a scuba tank via whip (not shown). Whip connect to the fitting directly below the Gauge. Start by opening the valve for bottle #1. Make sure you only turn 1 valve on at a time. If you turn on more than one valve at a time the bottle will blend the air together lowering the pressure to the average of the bottles. Once the scuba tank fills to approx. 1000psi from the first bottle shut the valve off and turn the valve on for bottle # 2 which will fill the scuba tank to approx. 1500psi. Turn the valve off and move to the valve for bottle #3 and continue the process until your scuba tank is filled. Notice with this system you can be filling the cascade while also filling the scuba tank. I hope this helps.

 

[Gone for diving]

Yeah I am sorta getting it,

very interesting way to do it....

 

[RickyVR]

Yeah I am sorta getting it,

very interesting way to do it....

call if 7012388314 if you have questions

 

[Cio]

Don't use hydraulic stuff, hydraulics don't do much when they fail, pneumatics do. They are designed as such, need proof, compare valves for hydraulics vs pneumatic for the same pressure. Its not a guaranteed explosion but you can get pneumatic stuff for the same or similar cost so why bother. Hydraulic hoses are the same cost as comparable pneumatic hoses, why bother with them?

Trunnion 3 ways from Swagelok are the norm and they are expensive, you can just use two regular ball valves and achieve the same thing. often found on ebay for cheap.

Don't buy a coil of tubing, get straight lengths from a local supplier, you'll thank me.
Pro tip: Make loops by wrapping your tube around the D.O.T. caps, two loops is unnecessary but looks a tad nicer in my opinion.

Your compressor probably isn't too small, your consumption determines the comp size, not so much the bank size. (be sure to run it appropriately)

I would not recommend you put ACD's in but if you insist, Jorc has what you are looking for.
Pro tip: You can source zero loss drains for every stage except the final stage. I'm not sure Jorc has these but they are available. Rumor has it, the new Bauer's have HP zero loss drains but I haven't seen just the drain for sale yet (give it a year)

If you need help sourcing , DM me I can point you in the right direction.

 

[-JD-]

You need the control unit for automatic drainage? DIY: click

If you need solenoids - there's only 1 that releases the pressure after the first coalescer. Because of the pressure drop, the valves of the other coalescers will open as well. Of course you can add a solenoid for each coalescer.

Sorry to necro-post, but @Miyaru , I had a follow up question to this post.

Are you suing some sort of pneumatic pilot-valve system to trigger the subsequent-stage drain valves after the first, solenoid-controlled drain? Or am I misinterpreting your statement?

Pics, drawings, links, etc would be appreciated if applicable

Thanks!

 

[prid1279]

@rob.mwpropane Any further progress?

I really need to get onto copying @Miyaru auto pressure sensing setup. Love that idea and just reminded myself when I came across this thread again.

 

[rob.mwpropane]

@rob.mwpropane Any further progress?

I really need to get onto copying @Miyaru auto pressure sensing setup. Love that idea and just reminded myself when I came across this thread again.

Absolutely.zero.progress. The only reason the bottles moved is because we moved the sea container that they currently reside in here at the shop, lol.

I am 90% done a trimix controller (based on raspberry pi), I am 90% done building the nitrox stick, I am 70% done the banking system.

The only good news I have to share is I have been diving a LOT! At least 3 or 4 times a month. (that's a lot for me with a full time job, kids, wife, etc.)

I might have ADD or ADHD I really hope to get something together this fall when it's cooler and I can save my filter when pumping all those bank tanks up. I will start a thread, post pics etc when it's all complete.

 

[prid1279]

Getting out in the water is better than fiddling in the shed because you can’t get out.

Trimix controller sounds interesting, keen to see the outcome when you get to it.

 

[rob.mwpropane]

Getting out in the water is better than fiddling in the shed because you can’t get out.

Trimix controller sounds interesting, keen to see the outcome when you get to it.

I agree, I'd much rather be diving.

Not at all my design. I think it's been linked on here. And I shouldn't call it a controller, more of a mixer / analyzer. You manually control He / O2 and watch the screen to get desired mix. Basically the short of it is you add He to drop the O2 through one stick and then raise the O2 back up via another stick. Make sense? (by stick I mean nitrox stick with analyzer on it... so 2 O2 sensors).

GitHub - divetools/Gas-Blending: Python apps to assist with Gas Blending

Python apps to assist with Gas Blending. Contribute to divetools/Gas-Blending development by creating an account on GitHub.

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