Tuxing double cylinder pcp air compressor - taking the plunge.

No disagreement Mike. Just trying to point out a potential alternative solution. The Zeolite solution is certainly viable as most SCBA breathing air compressors use it. My back ground is 20 years in Semiconductor Fabrication Equipment maintenance and engineering. I will look for a link but I have not seen one other than what JoeB says which is certainly not infallible in my experience. I am currently using 3A zeolite since I have it on hand for removing water from the alcohol fuel I distill (federally permitted). I will be ordering some Activated Alumina soon for experimentation.

By the way move your radiator / fan array to the other end of your cooling loop between the compressor low pressure head and the tank.

Thurmond 
 
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Thanks. I think either medium works. Yeah, I’ve been researching and some technical references on heat transfer and fluid flow show the cooler as I have drawn, and others show it as you recommend. I can think of pluses and minuses for both. I’m thinking I’ll do as you recommend since that keeps the tank and overall system temperature lower I think, plus there is a greater temperature differential across the cooler your way. Appreciate the expertise and recommendations. 
Mike
 
Mike the way I specified the cooling loop is identical to my AV Compressor. Always best to put the radiator after all heat sources are input into the solution for the greatest Delta-T of the cooling loop. This is important for the AV compressor since the reservoir is plastic.

One other note Mike: Alkaline solutions are used by industry to strip anodizing from aluminum so an alkaline byproduct attacks anodizing very quickly.

Thurmond
 
For color change simply "salt" some indicating desiccant throughout your Zeolite "bed" rather than using a product that is all color change. A tablespoon of color change silica beads mixed with the zeolite is adequate. I prefer the orange beads since the blue contain cobalt chloride which can also be an acid producer under certain conditions.
I get my silica beads on e-bay.

Thurmond
 
Wow That compressor and motor looks just like the Air Venturi compressor and motor. By the way my Air Venturi is dead. It died sat when the burst disk ruptured. Don't ask me ask me what happened all I know is it burst and now the high pressure cylinder, the back one is dieseling and dumping oil and carbon in to the water/oil separator filter. Air gun Depot said they would have it picked up, and a new compressor on the way. Already got the email. I bet you won't get that kind of service from Chinabay.
Good luck
CH
 
True dat. ;). Couldn’t wait until Saturday so after work today I decided to see if f it worked or not with the bucket cooling. So, I checked all fasteners tight, inserted the correct amount of Royal Purple Compressor oil, got out my Tuxing air dryer (same as Diablo), hooked up the tubing and sump pump in 5 gallon bucket and turned it on. I let it run for 15 minutes unloaded, and shut it down. Rechecked everything while it cooled for about 20 minutes. Then hooked up a 45 minute SCBA tank at 3400 psi and started filling. It took about 12 to 15 minutes to get to 4500 psi (where I had set the auto shutdown), and it shut off at the correct pressure. Bled everything down, disconnected the SCBA tank and hooked up my small 90 cubic inch field tank. It took about 3 minutes to go from 3500 to 4500 psi, and again shutdown. Temperature never got higher than 60.5 degrees C. So far so good. I’ll get some photos and more exact fill Times this weekend. All the parts for my cooling system upgrade haven’t arrived yet. 
 
Decided to use Royal Purple synthetic compressor oil in the Tuxing two cylinder HPAC. I only ran the unit for about 15 minutes unloaded and about 20 minutes loaded (filling tanks) on Wednesday, and things seem good to go so far. FYI, ISO grade 100 oil is equivalent to SAE 30 weight motor oil viscosity.

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I'm trying to find a maximum operating temperature for the Tuxing two cylinder HPAC. I don't think anything came with the compressor, and I've heard on the smaller Yong Heng units that around 65C to 70C was their recommended limit (same HP cylinder). I think the AV compressor supposedly can run at a higher temperature, but I'll limit my HPAC to 70C. See below from the Pyramyd Air web site regarding the Air Venturi compressor, which is very similar to the Tuxing.


"Normal operating temperature as we were testing them was around 75C. We had a few units go a little above this but no more than 5-7C. That's typically only when filling larger bottles. The only time I've seen one go over 80C was when we checked to see how hot it will get with one of the pre-production units without water. That unit went over 95C. There is a shut off built in that should stop the compressor if it goes above 95C."
 
Hey guys. I have been following this thread with quite a bit of interest. May have to have one. But one thing I was wondering; does this unit have any kind of water purge system (condensate drains)? Molecular sieve filters are designed only to remove minute traces of water.
Source: https://www.scubaengineer.com/high_pressure_compressor_filtrat.htm
Charlie
 
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It does have a manual purge at the bottom of the outlet valve block. I normally purge once in the middle of a fill from 3000psi to 4500psi in my SCBA tanks. Before you buy, let me complete the modifications to the cooling system and get some run time. I haven’t had it long enough to recommend. I have had to upgrade the electrical since it comes ungrounded. The plug has a ground prong but it’s not connected to anything on the other side of the socket. Easy fix but shouldn’t be necessary. I’m also going to open and inspect the outlet valve block to ensure there is no corrosion or silica beads inside. If there are I’ll replace with a cotton filter plug, since I’m using the Tuxing (Diablo) style dryer/filter with molecular seive . I’m in the middle of the mods now, here’s a few photos of my progress. The aluminum water tank on top isn’t hooked up, and the fans and water pump aren’t wired. 

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Still waiting on the AN6 fittings for the 4 liter aluminum supply tank. Once that is done, I'll fire it up and see how it works. I've hooked up everything electrically and also mechanically except for the connections to the tank. Its been about 3 weeks since I ordered the parts so those fittings should be here any day now.

I am also installing a vent/drain valve at the inlet of the filter/dryer so that I can drain any condensate that ends up at the input to the filter housing, even though I am keeping the inlet of the housing above the outlet of the compressor discharge valve body. Oh, and I also grounded the system (installed a ground wire from inside electrical plug connection to the base of the motor housing), since it comes ungrounded from the factory.

I disassembled the outlet valve housing, and found wet silica gel beads inside, and the cylindrical basket that holds the silica was already starting to rust. I removed all the silica, cleaned out the housing, and replaced the silica with one of the cotton tampon type filters that come with the unit for the small external filter. It fit fine inside once I trimmed about 1/4" from the overall length of the tampon.

See all those fittings for the 3/8" hoses on the photos above? Yeah, well it turns out I needed small hose clamps on all of them even though they are barbed. ;) When I hooked up a water supply and pressure tested the system I had leaks blowing water all over the place... Also, that pump puts out 35 psi pressure, and the major flow restriction is the radiator. So that being last in the flow path caused the entire system to operate at a higher pressure than I wanted. So I decided, since the delta T on the cylinder heads really isn't significant, to use my original flow path of tank, pump, radiator, cylinders, tank. This way the higher pressure part of the system is only from the pump to the radiator. 

More to follow once I receive the fittings from eBay. Its looking good so far, but you never know until its operationally tested...
 
Still waiting on the AN6 fittings for the 4 liter Aluminum tank, which I ordered from eBay December 2nd. I keep getting this status, which has shown now for over six days. Those fittings are all I need to start testing this compressor and the cooling system modifications.

Processed Through Facility 2017-12-20, 19:50:00, ISC SAN FRANCISCO (USPS)

Estimated delivery Wed, Dec 13 - Tue, Jan 02
 
Filled two 45 minute SCBA tanks from 3000 to 4500 psi. Took approx 13 to 14 minutes each tank. HP Cylinder temperature meter got as high as 58.5 C. As you can see, I did this where I took the photos in a warm garage with the sun shining on the compressor. Probably worst case conditions. Water temperature meter got as high as 40 C. All in all, I’m calling this a success so far. Run time is only at 1.7 hours, so much more use before I’m totally on board. Basically the temperature rise is about the same as using the 5 gallon bucket. If you look on the photo of the side with the water pump you can see a small 12 Vdc blower that I installed to attempt to cool the outlet valve block. It’s warm, but not hot using this small blower. If anyone is interested in more detail please PM me. Merry Christmas and Happy New Year!
Mike
 
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