Panel revision

I've tweaked the design yet again; if I use 4-way connectors, I can get rid of half the 3-ways, plus the connections between the.  Of course, the 4-ways need to be less than twice the price of 3s.  Not always the case.

The big question is to use tubing for the 'manifold' or to use NPT.  If I use nipples to connect the manifold pieces, they'll be quite tight.

Ode to Denton

I don't know Denton.  But like a lot of other divers-with-compressors, we've used his website as a resource and inspiration for our own setups.  He took a LOT of time writing up detailed instructions on how he set up his impressive mixing system. 

It seems he announced the website in June of 2006, and later that month I start to see mentions of his funeral.  I'm not sure of the details what happened, but the information is out there.  I find a lot of similarities between he and I and it is interesting- and not surprising.  He would have been 41 years old this year, was a computer engineer and loved to dive and travel.  And he died while diving, apparently after a great dive, and apparently for no reason other than it was his time. 

So, not only do I feel a kinship with him as a technical person doing technical diving, but I've got another reminder of him- some of my bank bottles and hardware came from his setup.  From what was posted about him, I'm honored to be using some of his equipment in the way that he meant for it to be used.

Good Journey, Denton

Designing the mixing panel

It's a curse to be an engineer.  I've spent days and days trying to design a mixing panel for my compressor.  First I had to figure out how to set up my bank bottles.  I've sketched it all.

My goal was to be able to run the compressor and either fill a bank or fill a bottle.  Furthermore, I wanted to be able to run the compressor and fill a bank... while filling bottles off a different bank. That is what made it interesting.

Initially, I had come up with doing it using 3-way valves.  It made perfect sense- each bank could either be turned to the bottles or turned to the compressor (manifold).  I could fill two banks at once, and still fill bottles off the third bank.  Here's a sketch of that:  

 But then reality set in.  I can buy needle valves for $12 up to $40 for nice panel-mount ones.  The absolute cheapest ball valve I found was $90.  And $170 for a 3-way panel-mount.  Ouch.  And then, every subject expert I spoke with said the same thing: ball valves aren't what you want.  Besides the up-front cost, they leak, they are expensive to rebuild, and they 'shock' the system when flipping from one side to another.

So we're going to use line valves.  I took a look at Gypsy Divers' setup and liked their big panel.  It made sense walking right up to it.  With that in mind, I came up with this.  Unlike the 3-ways, any gas changing requires two knobs to be twisted, but needle valves also let you do flow control.

At this point, I need to decide on how all these are going to be plumbed.  Flex hose is easy- but it isn't cheap.  Steel tubing seems to be a popular design, so I'm going to look into it further.