My unit build

W

WFO

Member
Somewhat of an ongoing project here...


The overall concept is for a sort of meg-shaped unit. Started off life as a load of fag packet sketches and drunken chats with my mate, until a couple of cylinders landed on my doorstep and I had to make a start.

This is the concept, nothing new here. Exhale into the outer diameter of the case (via a hose on the top of the head)... gas goes in through the radial scrubber... up the middle... swirls about a bit around the faces of the cells in the plenum and out of the top.

sectiondrawing.jpg



As for the rest of it, my mate is making me some counterlung outer bags, the T pieces I haven't sussed yet but I'm getting there. And a draeger ray loop at the front of it.

The gas parts, I've designed some gas blocks, a bit like sentinel/boris blocks but free flowing enough to run a BOV from. Feeding that via some swakelok bits and normal hoses to one of those fancy mass flow controllers which will hide in the head (parker porter VDC-1000)

Electrically, full MCCR. I've done the code for an AVR ATMEGA to run an LCD display and basic HUD which should do me for the time being, not built it yet, but got the bones of it.

After I've dived it like this for a while with just NDL stuff I'll be adding some more redundant systems. Plenty room in the sensor casing to add a horseshoe board with some interesting electronics on it.


radialg.jpg

vcqu.jpg

b2nc.jpg

vwku.jpg

qb31.jpg

xk01.jpg


er8a.jpg

you could fit 6 cells if you could be arsed!

qgwn.jpg

SWARF EVERYWHERE! It's in my tea... in my ears... the garage is full of it... I've had to stop smoking because it got in my tobacco... my missus is doing her fookin nut... AAARRRGH...
 
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What I don't like/not sure about it:


The cell backs aren't exposed to exhale gas... this is also a plus point as it keeps the wiring dry... on the other hand will it make them "lazy" from temperature compensation perspective?

There's quite a bit of wasted volume in the head.

Will popping 2x M8 bolts into the head be strong enough for a lifting handle?
 
You know it will never work right until blood or skin has been sacrificed to the gods of the workshop, right?

Looks pretty nice, sure you'll deal with the excess space and back temperature in rev.2 :)

Re the temperature issue - a few trial runs to see how it goes as is (with known gasses and a mechanism to generate a temperature differential) might be a good idea.
 
Hi,

What's the outer diameter of the cylinder, did you machine the cylinder ends on your lathe, guess you used a saddle (correct term?)to support the cantilever end out in space ?

Very interesting project, keep us posted how it progresses.

David.
 
194 OD or so IIRC

No, cylinders too big for my lathe. just held it in hard jaws in a 12" chuck and turned a steady band (shiny bit you see near the end) then supported it with a fixed steady with rollers.

Thought about trying it just waving about in space but think it would have chattered.
 
Re

My Duthers,


This workmanship is too accurate and precise to be considered a homebuild unit evenif the shop is at your house....(said enviously)

Great job attention to detail is fantastic. Do you do custom work by requests if engineering specs are provided?

/r

Michael
 
I've got the homebuilders bug now! If you've got to have swarf then delrin swarf is the best!
Nice work!
Henry

Sent from my SAMSUNG-SGH-I337 using Tapatalk 4
 
Errr, I already have the concept in my head for the next one/BOB. Next one will have the cells in a horizontal plane and a half-sized scrubber. This is kinda fun :)

Just waiting for some cash to land and then I'll get the perforated stainless to make the scrubber outer sections :)

mkontodiakos said:
My Duthers,


This workmanship is too accurate and precise to be considered a homebuild unit evenif the shop is at your house....(said enviously)

Great job attention to detail is fantastic. Do you do custom work by requests if engineering specs are provided?

/r

Michael
Click to expand...

You're too kind Sir! You haven't seen the whole unit yet! Might look like a dog's dinner!

Yeah I'll make owt if it interests me :) I'm also an engineer for a living and I know some really good subcontract shops if I ever need to get a grown-up to help :dizzy:

I'm a better designer than I am machinist.
 
Impressive work!
Just out of curiosity, you made the can out an S80? Aluminium?

Tom

Ps: I am gonna be ashamed the day I put my work on the forum :worship:
 
Deltatom80 said:
Impressive work!
Just out of curiosity, you made the can out an S80? Aluminium?

Tom

Ps: I am gonna be ashamed the day I put my work on the forum :worship:
Click to expand...

Definitely ally, think it was an 80... or maybe an 11l ... I think it was 200 bar, really regretting scrapping the neck before writing down what it was...
 
Deltatom80 said:
Any worries about corrosion? Or do you intend to treat the surface?

Tom
Click to expand...

Not worried, ally gets a skin on it and at worse looks a bit fuzzy. I'll probably aluchrom the O ring surface (and it will be greasy anyway) and spraypaint the rest.

It is only going to get hammered against bits of wreck, van and boat anyway so perfect finish doesn't bother me.
 
Next bits... put the circuits together on the bench... then do the PCBs... then I can see how the handset housing is going to look.
 
4u1x.jpg


Scrubber outer, starting to look a bit more unit-y. Need to do the inner screen and fix it all together eek!

Code for PPO2 monitor is slowly driving me barmy.
 
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