Rix SA-6 Rebuild - winter project

[maniago]

Again just another thought on that automotive air intake filter, try again the charging rate time test with and without the air filter fitted
just to make sure its not starving the pump at full 1500 RPM.

Ref the vacuum cleaner note above...more likely the filter is laughing with this kind of puny flow @ 5cfm.

One last note on the intake tubing, it really dampens out the intake pulse sound - more of a nice growl that I can stand without ear-buds vs without anything...

 

[iain/hsm]

Thanks for all this Iain!

I know you're not a fan of the 1st stage coalescer I have - youve sent me the numbers on why and I get it, but I've gotta tell you that I'm getting the same amount of water out of it as I do my second stage, and its not trivial. That and the two "old" second stage heads I acquired were locked up solid with rust - one an old AL head, the other a SS head tells me something. In anycase, given that it does nothing sitting on the shelf, and it doesn't wear out in use, well, you can see my point.

Funny on the intake hose - its standard swimming pool plumbing hose. And the intake filter? $7 HEPA filter for a Dirt Devil vacuum. Can't beat that with a stick!

I'm tracking with the tuned pipes - just like we used to keep our old 2stroke bikes "on-pipe" when scrambling. Maybe I'll chase that animal with the lower 1200rpm just for $hits and giggles! Cheers!

Also consider a Dywer magnahelic gauge pressure drop test on the intake hose or just use a 1/4 inch plastic tube with a bit of coloured water to see the suction column, (borrow one from a service tech at a dive shop)

As for the rust in the heads, either not enough turns of the bleed knob during filling or a forgetful filler LOL or too much cooling on the approach allowing the water to condensate out. Easy call which to pick. LOL

Too low an approach temperature is a more difficult problem as it can also lead to "hydraulic" failure of the reed valves, same as not draining enough. Water condensing out before the inlet and discharge valve can cause deformation of the valve as the water being incompressible forges the reeds into the head ports makes a little dimple or hollow on the reed valve, like a burst disc on a pillar valve when you first fill the cylinder with gas.

Would never have guessed the vacuum part looked like one of those chromed air intake filter on "souped" up boy racer cars.
As for the swimming pool hose, not much call for open air pools my neck of the planet.

Best we can get is stuff used for draining fields ditches and culverts so the rain don't reach over your boots.
Asking for swimming pool hose at our hose supplier would I fear not get a positive response LOL

On the noise side yes you can reduce noise by 30% using the 15 foot hose and sticking the intake filter outside.
The fan is also a big culprit, although wont suggest taking it off.

We have both zero degree or 30 degree pitch angle black cooling fans all 8 blade for the UK builds.
I see Rix USA use that horrid white thing you have just added (must be an cost to import thing I guess) LOL Iain

 

[maniago]

Also consider a Dywer magnahelic gauge pressure drop test on the intake hose or just use a 1/4 inch plastic tube with a bit of coloured water to see the suction column, (borrow one from a service tech at a dive shop)

Haha, I'll go one better and use the throat manometer I use to balance the 4 Dellortos on my AlfaRomeo!

 

[iain/hsm]

Haha, I'll go one better and use the throat manometer I use to balance the 4 Dellortos on my AlfaRomeo!

Your on your own if you do. Way too much calculation Cv venturi factors and friction losses for a Friday. We have enough problems on this forum trying to encourage basic P1 V1 T1 cals without the "How long does it take to fill a 80" with my compressor. LOL

Besides I thought you said this was a winter project, You've taken long enough already with a few bolts and a bag of bits,
A week end with a couple of spanners (Crescent wrenches to you lot) and a tube of grease would have been sufficient.

Its gonna take me years now to get over this and convince anyone to buy a Rix,
They all think you now need a fully equipped workshop and an engineering degree to
consider an oil free compressor.

That and with Swamp Diver expecting we supply spectrographic gas analysis and flame ionisation for possible airborne long chain hydrocarbons,
So much I now have a avid fear of gardeners lawnmowers. Grrrrr.

Hey have a great week-end enjoy the warm sun and pool. lol Iain

 

[maniago]

LOL - so long and thanks for all the fish!

Mani

 

[swamp diver]

That and with Swamp Diver expecting we supply spectrographic gas analysis and flame ionisation for possible airborne long chain hydrocarbons,
So much I now have a avid fear of gardeners lawnmowers. Grrrrr.
Iain

I think those would be straight short-chain volatiles which we would be talking about where those in the C7 to C8 range are the most narcotic. As for the aromatics they are even more narcotic and there are lots of both vapors floating about in people's garages. Possibly you Brits don't have garages to store all the nice products we typically can keep in our garages such as gasoline, diesel, hexane, methylene chloride, trichloroethylene, driveway sealer, paints, etc.

Over here (US and Canada) we've been using PID, FID and GC/MS to analyze compressed breathing air for what close to 25 years now and the system works very well. Lab sends you a sampler, you fill it up, and the unbiased trained analytical chemist who participates in a QA program quarterly sends you the result. Couldn't be simpler. Draeger tubes are antiquated and while useful for screening for specific VOCs out in the field they are pretty much useless when you don't know what compound you are looking for. GC/FID is a far better screening tool for VOCs.

After you've seen enough dive compressed air samples fail for total volatile hydrocarbons whether the compressor is a Rix or not you'll want an adequate AC bed in any purifier to eliminate the risk of intake air contamination. The intake setup below is a not so uncommon dive compressor intake set up. I've seen dozens of samples contaminated by gasoline vapors (petrol for your lot) over the years.

Have a look at the new EN12021 coming out later this year. At least for mixed gases there will be a total volatile hydrocarbon lab analysis required.

So tell me is a Rix compressor oil-less or oil-free?

 

[maniago]

I decided that perhaps the basement would be a better place to pump gas instead of the garage - its cool, not damp (walk out basement), and doesn't have any obvious bad chems. That said, getting a 300lb compressor over the lawn turned into a challenge not solvable in its current state of mobility - so a redesign was in order (courtesy of Lowes). Much better now. I might have to put a trailer hitch on it too!

(yeah I know, move the caulk tubes and keep the compressor off the wall....)

 

[maniago]

She passed O2 compatible -2003 (I) & CGA G-7.1-2011 GRADE E tests today with the LF 65240 filter cartridge.

Better news is that without any filtering, just using the coalescers, she passed everything for the above specs, except for water which dewpointed at -45F instead of the spec -65F.

So she's running pretty clean and the ambient 45%RH 68F basement air (which was also sampled) is good.


Thanks to everyone who helped me learn. I'm sure to have more questions as time goes on. Cheers!

 

[NAM001]

Its a wonderfol compressor isnt it