New Toy - Airetex 45 w/ CB Nitrox

[Brandon]

I finally tired of dealing with my local shop's BS and decided it's time to go back to filling my own cylinders. I had good experiences with a W32 Mariner that my former dive club still operates (though 900 miles away); and it looks like Airetex finally figured out the kinks with their smaller compressors. Ordered up an Airetex 45, and I'm almost done getting her all set up in my garage. Still need to plumb the intake / gas lines, and there's "just one more" box of fittings that should be here on Monday...



I've only had the opportunity to fire her up briefly to check rotation after the new 220v outlet was installed, but I'm very impressed with how quiet and smooth she runs. Will not bother the neighbors one bit (though my garage is also very well insulated.)

Airetex 45 compressor
15" Midland Series 88 Filter Canister (X88240)
35" Mako Filter Canister (X65247)
Oxyhacker Stick
Oxycheq El-Cheapo II O2 Analyzer

Haven't been able to fully test her yet, but I see no problems exceeding Modified Grade E. That will get me started at least =)

CB Trimix and PP blending for deco gas to follow.

-B

 

[iain/hsm]

and it looks like Airetex finally figured out the kinks with their smaller compressors.
I'm very impressed with how quiet and smooth she runs. Haven't been able to fully test her yet, but I see no problems exceeding Modified Grade E. That will get me started at least =)

CB Trimix and PP blending for deco gas to follow.

-B

Having just looked over the Airetex 45 website and reading the albeit "little light" specification on the web. I would question first there "Designed and Made in America" claim.

To me it seems a little far fetched when I can clearly see just from the photos that:

1. The block was designed and made in the Peoples Republic of China and at that originally designed as a low pressure air compressor.

2. That the "new" silver colour anodised HP Filter was designed 35 years ago and made in Leicester England by a company incidentally I used to work for way back then and is no way close to a comparison to the original black colour hard anodised filter they original show on the web site.

3. The silver HP filter looks also to be missing a back pressure regulator (Priority valve) Not withstanding there claim of extending filter life. Without a BPR would IMHO only extend filter life as most of the moisture passes past the filter and into the tank.
Not quite what I would wish but this may in part be due to the product more appealing by its low cost more towards the paintball market.

4. Now from a photo it is very difficult to asses this particular block con rod bore size.
These little chinese blocks have a number of options. But from memory its either 65mm, if so with a designed maximum 980RPM. Further as the next size up is an 80mm con rod bore with an even lower 850RPM maximum rated RPM

5. So it beggars the question why the big play on the web site for the AireTex 45 running at 1100RPM when this so called low RPM is higher albeit marginal than the original chinese manufacturer intended designed 980RPM.

6. I read on there You Tube posting and I quote:

The AirTex 45 is different from every portable compressor currently available. When designing this compressor we looked at everything that was failing on the competition and made it better".-B

English proverb "The Chinese are not slow about running fast" but when you "lump" on an equal weight piston head set and liners to a low pressure compressor block without consideration to balance and "throw" you take on a whole route of different .

7. Also from there You Tube video it states:

" Fiberglass fan guard, no metal rattling"

Yeah right LOL Try this:

Airetex 45 compressor - YouTube

Not a good start

8. Now I'm going to take a guess here and suggest that precious little design was done on that block for CB Trimix, further I doubt any testing has been done on its efficiency with Helium let alone Nitrox. So out of interest "in testing" what percentage of nitrox over 40% was the block factory tested to?

And further for consideration can you also tell me if the manual states the allowable "blow by" using Nitrox and Trimix and also from your manual the diameters each of the pistons and the piston stroke also if stated the maximum allowable rod loading.

You see if AireTex compressors are going to make claims about the "failing of the competition" you need also to be able to back it up.

So by way of example and speaking as a diving engineer if your going to claim design of a compressor as they say and

We looked at everything and make it better than anyone"

You would think that they could have also "designed" and "made" it so that silver filter tower wasn't hanging off the frame edge so much.

Just a thought. LOL Iain Middlebrook

 

[Brandon]

Rofl, thanks Captain Buzzkill =) My excitement is obviously getting the better of me.

I was irritated that they switched to the Midland filters, and it's totally bizarre that it shipped without a priority valve or check valve. They also somehow forgot to include a fill whip. Those bits are in the pile of parts I have coming on Monday.

The manual is pretty light on technical info - nothing about blow by, the piston diameters, piston stroke or rod loading.

I'm with you that they seem to be much more focused on the paintball / airgun market than diving... we'll see how it all shakes out.

-B

 

[iain/hsm]

Rofl, thanks Captain Buzzkill =) My excitement is obviously getting the better of me.

I was irritated that they switched to the Midland filters, and it's totally bizarre that it shipped without a priority valve or check valve. They also somehow forgot to include a fill whip. Those bits are in the pile of parts I have coming on Monday.

The manual is pretty light on technical info - nothing about blow by, the piston diameters, piston stroke or rod loading.

I'm with you that they seem to be much more focused on the paintball / airgun market than diving... we'll see how it all shakes out.

-B

I know engineers can come across such, its just we can be a grumpy lot especially when there is so little technical detail to keep us happy.

Just a couple more finer points with regard to these missing parts, You do realise that this English filter or yours may be threaded 1/4 BSPT (British standard pipe taper) as its our standard thread and not the standard American 1/4 NPT (National pipe thread)

You may ask whats the difference, 5 degrees in the thread angle and more threads per inch in the pitch, so much so that in the 1/4 size its about half a thread difference and if your whip thread is made of steel or stainless then its much harder than the soft HE30TF alloy of the aluminium female taper thread on the filter base.

Thereby when to connect the two miss matched threads at best it will leak and when you tighten more, its gets worse as it damages the protective anodising of the aluminium as it tries to recut a new thread pitch galling into the light alloy.

Over time the alloy oxidises and swells and eventually fails.

One reason why the superior quality of the hard anodised black filters use stainless adapters on both inlet and outlet to connect tapered fitting and the thread into the alloy filter base is always a parallel 9/16 x 18 SAE thread sealed simply with an o-ring. Further if you gaul up the adaptor its an $8 part

 

[kelemvor]

Looks like a nice setup, congrats!

 

[Brandon]

Airetex quickly sent me the missing parts, and I was able to get everything more or less finished.

She's all plumbed in, checked over thoroughly, run up for a couple hours and I submitted a gas test. Results will come back on Wednesday, then I'll go grab a cylinder of ABO and start blending nitrox. Have dive plans next weekend and its looking like everything is coming together right on schedule.



A BIG thanks to Iain for the warning about the BSPT threads on the Midland housing. When I added the missing priority and check valves, I avoided disconnecting those fittings and was able to complete the connections without issue. In looking at them closer, they do appear to be on adapters from BSPT to NPT, but I haven't confirmed that.

 

[OkByMe]

Priority valves after every filter and the filters in series, I have 2 large separate filters and 4 small ones in a bank - each has a valve. It does not matter where the unit was made - I have an Alkin since 2006 and I think it was made in Turkey, and it still runs like a top to fill @4500 psi.

You can see my setup here if you are interested. Please wait

I had a bit of a problem with mine close to the wall like that. So I found a narrow 125v. box fan that is a little larger than the impeller fan opening and put it between the wall and the compressor belt guard so it blows across the block. I turn the box fan on before starting the compressor and shut it off after it cools down.

 

[Brandon]

Hahaha, glad to see someone else overdesigned their small compressor. You went even farther than I did! =)

 

[OkByMe]

Hahaha, glad to see someone else overdesigned their small compressor. You went even farther than I did! =)

It does seem a little extreme, but all the controls can be migrated to any other setup. My goal was to make it completely un-attended and portable. Any four wire RV or dryer/range outlet will power it. It will fit into the back of the Expedition if I tow the boat (put tanks in the boat) or I can take my little trailer and my tanks including the Oxygen bottle and reg. I need the 32% banks to blend trimix though. It takes a while to punch up all 3 storage tanks from 3000 to 4500psi.

 

[OkByMe]

I have made a nice addition to the SCUBA contraption. To eliminate chasing around for Oxygen, I just make my own. Cost me 450 which will pay for itself in 3 "T' tanks of Oxygen.

Oxygen concentrators bought surplus and de-saturated. Oil-less compressors that were used with same, all mounted on a uni-strut frame on the wall. The output from the concentrator bank will supply enough volume to bank 40%, but I cut the flow back for 32%.