Using a Tuxing Water Separator on the Input Instead of Output

[Squirrelmageddon]

First, this is NOT a process that is in any way an attempt to replace a water separator on the output side of the compressor. This is a project to show the effects of using desiccant to lower air moisture before the compressor.

With that being said: The Tuxing is a great filter, however, it makes fill time much much longer and I ended up moving to a smaller 7" filter on the output side. I happened to see the internals on a big duel pump compressor and noticed it used the Tuxing filter internal as the main intake filter. That's a great idea so I figured out how to do it on my little GX CS1 compressor which is the smallest in the GX lineup. The Tuxing's internals make an awesome filter and the heavy outer case is not needed since it's only under the pressure of a slight vacuum from the compressor's intake.

EDIT: The video showing the humidity level dropping from 69% to 18% is 7 posts down.

The smaller GX compressors have a very basic 1/2 long conical brass filter with a 1/8 BSPP thread on it. Perfect! I can thread in a spare air line I have into the compressor. You can see the stock filter and where I screwed in a high pressure line I had laying around.

So the new line goes to the back, turns to the back left corner, does a 180 bend back to the top rear right side of the compressor. I then drilled a hole in the top of the case, and pushed the M10x1 male thread of the hose through the hole. Since all Chinese filter thread and hose male threads are M10 x 1, I inserted a nylon spacer from the hardware store and screwed the end of the Tuxing filter on. Now I can easily see the state of my filter media and easily change it out at any time.

I tested it a few minutes ago and it is a hot humid night here along the Texas gulf coast. I typically bleed the line of moisture about half way through my fill. Normally, I get water splattering from behind the bleed screw knob. Not anymore! I was almost dry. I'm pretty confident that the 7" output line filter got the rest.

 

[rcs9250]

Very interesting. Although one session isn’t big sample group but you saw a result that was different from your norm.
I guess a fair/definitive comparison would be an air analysis of a sample from each method. But that would cost a bit of $$.
Also, a dwell time in molecular sieves is key, that’s why they work best when they don’t release air until 1700psi or so.
But like you said, there was no water. But of course doesn’t mean there isn’t moisture in the final airstream.

 

[CharlieF]

The issue is that the moisture is wrung out of the air when it is compressed. The filter on the output absorbs this wrung out moisture before it enters your airgun or tank. Putting a filter on the intake side does little or nothing to keep water out of your airgun or tank. It may filter out dust or other impurities but that is about it. If you live in a low humidity environment, you may only need an intake filter

 

[Squirrelmageddon]

The issue is that the moisture is wrung out of the air when it is compressed. The filter on the output absorbs this wrung out moisture before it enters your airgun or tank. Putting a filter on the intake side does little or nothing to keep water out of your airgun or tank. It may filter out dust or other impurities but that is about it. If you live in a low humidity environment, you may only need an intake filter

Silica bead desiccant is used in just about everything we buy to remove moisture from the product packaging. It excels are pulling water vapor from air at normal atmospheric pressure.

I 3D printed nylon for years which is highly hygroscopic meaning nylon absorbs a lot of moisture from the air and it ruins 3D prints. Personally I don't have a roll out for more than 12 hours before I put it back into the storage unit to dry it back out. My storage unit is a 6 foot air tight vault with an air pump that cycles air though a box containing 2 lbs of color changing silica bead desiccant. This is a bad example because it is on a much larger scale over a much longer time period, however, I mentioned it because I've performed this drying process over the last 15 years and have seen the results in how much desiccant is changed out and my print results. I can actually measure how much moisture is in nylon by how much it crackles during the printing process and the clarity of the nylon post print.

Your right in that if you live in a low humidity location this project would be unnecessary. My problem is that I live along the gulf coast in Texas as it's humid AF most of the time. I'm going to get some actual numbers to see how much of an effect it has. I will record how many fills it takes before I have to change out the output filter desiccant. I will continue filling until the input desiccant needs to be changed. This will give us a ratio on how much the input is removing water vs the output.

So, if the output needs to be changed every 10 fills and the input every 100 fills I would say the input is doing 10% of the work. Sounds about right? I think so. I'll give it a go and see what the outcome is.

 

[beerthief]

I have thought of two things in line with this project . 1) a large box around the compressor with a De humidifier in with the compressor , and 2) a icebox with the output fill line running through it chilling the hot compressed air , then into silica bead desiccant filter and into the gun .

 

[Squirrelmageddon]

I have thought of two things in line with this project . 1) a large box around the compressor with a De humidifier in with the compressor , and 2) a icebox with the output fill line running through it chilling the hot compressed air , then into silica bead desiccant filter and into the gun .

Ya, I've been thinking of all types are moisture removal processes but I need to keep it mobile. Now that I have a line on my input side I can pull air from anywhere. What I may do is put a small hole through the garage wall, right behind my compressor, and pull air from the house. Pulling air in the garage on a humid Texas day kills my desiccant quick.

 

[AlanMcD]

I like it, but you are going to go through those desiccant filters quickly - when used on the output side, roughly 95% of the water vapor will have already been condensed out of the air stream from compression. All that will now be adsorbed by the desiccant . . . Of I were doing it, I'd want to first have the air flow be dried either by chilling it (could you pull the air out of a freezer?) or first through a big bottle of rechargeable silica ge;. That would greatly extend the life of that filter.

 

[Squirrelmageddon]

The issue is that the moisture is wrung out of the air when it is compressed. The filter on the output absorbs this wrung out moisture before it enters your airgun or tank. Putting a filter on the intake side does little or nothing to keep water out of your airgun or tank. It may filter out dust or other impurities but that is about it. If you live in a low humidity environment, you may only need an intake filter

I did some testing with the desiccant filter on the input. Here's a video with measurements from two hygrometers. It was 69% humidity in the garage and you can see at 0:53 the humidity coming from the compressor was dropped to 18%. The video is over 2 minutes long because I showed the results with the filter on and off multiple times. The humidity change should be immediate but those hygrometers take a good minute to adjust.

PS: Ignore my ugly ass hand. I was having an allergic reaction to something and it looks pretty F'ed up.

 

[rcs9250]

I did some testing with the desiccant filter on the input. Here's a video with measurements from two hygrometers. It was 69% humidity in the garage and you can see at 0:53 the humidity coming from the compressor was dropped to 18%. The video is over 2 minutes long because I showed the results with the filter on and off multiple times. The humidity change should be immediate but those hygrometers take a good minute to adjust.

PS: Ignore my ugly ass hand. I was having an allergic reaction to something and it looks pretty F'ed up.

Does your compressor have a bleeder for water ? If so, was there any liquid water when you open bleeder ?

 

[Squirrelmageddon]

Ya, there's a bleeder valve near the output line connection. Typically on a humid day the bleed valve will spurt out a little bit of water. It's been dramatically drier, when bleeding the valve, since I started using the desiccant in the input side.

 

[JimD]

How do you close off the dessicant on the input side? My concern is that if it is open all the time it will be all loaded up with water before the compressor starts moving air through it. I have two cartridges for my small dessicant filled filter and I was surprised how quickly the dessicant changed color in the spare cartridge even tough it was in a zip lock bag.

I think it's a reasonable thing to do as long as you don't only filter the intake air for moisture. It might be possible to take enough out at the input that the output is very low in moisture with a dew point lower than the air in the tank or gun will ever see but it seems like it should be easier for the dessicant to trap the water in the output since it isn't trying to remove moisture to the same level ignoring pressure and temperature. Most devices would have an easier time making 60% relative humidity 20% than making 60% 5%, in other words. But moisture removed from the input air is not going to be present in the output air. So filtering the input has to help.

 

[Squirrelmageddon]

How do you close off the dessicant on the input side? My concern is that if it is open all the time it will be all loaded up with water before the compressor starts moving air through it. I have two cartridges for my small dessicant filled filter and I was surprised how quickly the dessicant changed color in the spare cartridge even tough it was in a zip lock bag.

I 3D printed a TPU cap that fits over the input side of the filter. I have a spare filter sitting on my workbench which is capped on both ends. I haven't used it at all and it's still moisture free.

I think it's a reasonable thing to do as long as you don't only filter the intake air for moisture. It might be possible to take enough out at the input that the output is very low in moisture with a dew point lower than the air in the tank or gun will ever see but it seems like it should be easier for the dessicant to trap the water in the output since it isn't trying to remove moisture to the same level ignoring pressure and temperature. Most devices would have an easier time making 60% relative humidity 20% than making 60% 5%, in other words. But moisture removed from the input air is not going to be present in the output air. So filtering the input has to help.

Yes sir. The output filter is critical. I don't see any cons to setup a filter on the input other than having and extra piece of equipment to haul/maintain. The two positives are well worth it:

1) Less output side desiccant changes, however, you now have to change out the input side. This is fine because it's much easier to change out desiccant in the Tuxing filter.

2) Much less fitting corrosion. I'll have to see how much less over a long period of time. My son has a JTS compressor which he fires up in his room. It has far less oxidation on the fittings vs my garage compressor.

 

[rcs9250]

I realize you’re trying to eliminate as much unnecessary volume you need to pressurize with each use but it wouldn’t hurt to have one of these filters on the high pressure side just to catch any lubricant that might come through.

Air Venturi Compact Inline Filter | Pyramyd AIR

Keep damaging moisture out of your PCP airgun and make sure your compressor's filter is in good repair with this OEM replacement. Order yours at PyramydAir.com.

www.pyramydair.com

 

[Humdinger]

The issue is that the moisture is wrung out of the air when it is compressed. The filter on the output absorbs this wrung out moisture before it enters your airgun or tank. Putting a filter on the intake side does little or nothing to keep water out of your airgun or tank. It may filter out dust or other impurities but that is about it. If you live in a low humidity environment, you may only need an intake filter

@charlie F, thank you. I was about to write the same post as you have done so understandably. When the Tuxing TO32 compressor appeared on the market with this zeolite bead intake filter I realized that either they don't understand physics or they were selling a pig in a poke. Adsorption by zeolite beads is only effective under high compression. This is why output filters are usually paired with a Pressure Maintaining Valve (PMV) to not release air to a fill tank. The PMV is set to at least 1800 psi so the zeolite adsorbs the molecules of water vapor. Placing an intake filter at atmospheric pressure on the intake side is totally ineffective.

@Squirrelmaggedon, you should dump the zeolite adsorbant from that intake filter and at least replace it with colored silica gel beads so it will be at least minimally effective. Even silica gel filters are on the output side of low pressure home compressors rather than on the intake side. Silica gel beads work best between 5 and 10 bar.

 

[Squirrelmageddon]

I realize you’re trying to eliminate as much unnecessary volume you need to pressurize with each use but it wouldn’t hurt to have one of these filters on the high pressure side just to catch any lubricant that might come through.

Air Venturi Compact Inline Filter | Pyramyd AIR

Keep damaging moisture out of your PCP airgun and make sure your compressor's filter is in good repair with this OEM replacement. Order yours at PyramydAir.com.

www.pyramydair.com

I have that one but gave it to my son to use on his compressor. The one I'm using now is the same diameter but 7" in length and filled with color changing silica beads.

 

[rcs9250]

I have that one but gave it to my son to use on his compressor. The one I'm using now is the same diameter but 7" in length and filled with color changing silica beads.

If it’s the same size, maybe stick one of those cylindrical (filter only) in it or maybe half of one to capture any lubricant that might come through.

 

[Squirrelmageddon]

@charlie F, thank you. I was about to write the same post as you have done so understandably. When the Tuxing TO32 compressor appeared on the market with this zeolite bead intake filter I realized that either they don't understand physics or they were selling a pig in a poke. Adsorption by zeolite beads is only effective under high compression. This is why output filters are usually paired with a Pressure Maintaining Valve (PMV) to not release air to a fill tank. The PMV is set to at least 1800 psi so the zeolite adsorbs the molecules of water vapor. Placing an intake filter at atmospheric pressure on the intake side is totally ineffective.

@Squirrelmaggedon, you should dump the zeolite adsorbant from that intake filter and at least replace it with colored silica gel beads so it will be at least minimally effective. Even silica gel filters are on the output side of low pressure home compressors rather than on the intake side. Silica gel beads work best between 5 and 10 bar.

I guess I am just a total idiot, even though the very first thing I noticed on fill #1-3 was my bleed valve was spurting less water in this 70% humidity crap hole I live in. So that looked promising. I was going to perform a two 20 fill test and show the color changing desiccant with 20 fills non-filtered input vs 20 fills with zeolite filtered input. I didn't get there as I got called out a few times on how zeolite can "ONLY work with compressed air". My BF at OxyChem said put a hygrometer on it and show some numbers. So I did that and posted an uninterrupted video, showing the results. Here's is another test result which I do not have comparison pictures vs non-input filtered fills:

(Gold tube is my output filter with the emptied silica beads. The bottom filter is the input filter I used full of zeolite)

This color changing silica bead desiccant from my output filter after about 10x 580cc bottle fills. I took the time to separate the saturated beads from the dry beads for you guys to see. It has many more fills to go. Like I said I don't have a trial result picture of this after the same number of fills with no input filter. I can tell you, from previous experience, 10x fills, non input filtered, in 70& humidity, more than half would be green and the rest semi-green and orange. If I would have to put some numbers on it, I would guestimate 2/3 saturated, 1/6 semi saturated, 1/6 orange and non-saturated.

I use silica gel for other non PCP compressor uses and am pretty familiar with it. I've been using it on my output filters pretty much since day 1. I read a lot about molecular sieve zeolites and have talked to a close friend, who works at OxyChem, about it's usages. I read through several articles such as this one about it's ability to absorb moisture from an "air stream" not "compressed air" and it's effect to lower humidity levels in an HVAC system.

The Truth About Zeolites Used as Desiccants | Allergy Clean Environments

www.allergyclean.com

Another article from A&M about next gen zeolite usage in HVAC

An Organic Material For The Next Generation Of HVAC Technologies

Texas A&M researchers have enhanced the dehumidification efficiency of a polymer that could help develop more energy-efficient systems with a smaller carbon footprint.

today.tamu.edu

Can somebody check my video again and see if that "filtered" hygrometer on the right side was actually 18%? I may have discovered that I'm dyslexic and that reading was probably 81%. OH crap! I think I got it backward and the green saturated beads I've been seeing were orange and vice versa. *%$^ I may be dyslexic and color blind.

 

[rcs9250]

I guess I am just a total idiot, even though the very first thing I noticed on fill #1-3 was my bleed valve was spurting less water in this 70% humidity crap hole I live in. So that looked promising. I was going to perform a two 20 fill test and show the color changing desiccant with 20 fills non-filtered input vs 20 fills with zeolite filtered input. I didn't get there as I got called out a few times on how zeolite can "ONLY work with compressed air". My BF at OxyChem said put a hygrometer on it and show some numbers. So I did that and posted an uninterrupted video, showing the results. Here's is another test result which I do not have comparison pictures vs non-input filtered fills:

(Gold tube is my output filter with the emptied silica beads. The bottom filter is the input filter I used full of zeolite)

View attachment 400192

This color changing silica bead desiccant from my output filter after about 10x 580cc bottle fills. I took the time to separate the saturated beads from the dry beads for you guys to see. It has many more fills to go. Like I said I don't have a trial result picture of this after the same number of fills with no input filter. I can tell you, from previous experience, 10x fills, non input filtered, in 70& humidity, more than half would be green and the rest semi-green and orange. If I would have to put some numbers on it, I would guestimate 2/3 saturated, 1/6 semi saturated, 1/6 orange and non-saturated.

I use silica gel for other non PCP compressor uses and am pretty familiar with it. I've been using it on my output filters pretty much since day 1. I read a lot about molecular sieve zeolites and have talked to a close friend, who works at OxyChem, about it's usages. I read through several articles such as this one about it's ability to absorb moisture from an "air stream" not "compressed air" and it's effect to lower humidity levels in an HVAC system.

The Truth About Zeolites Used as Desiccants | Allergy Clean Environments

www.allergyclean.com

Another article from A&M about next gen zeolite usage in HVAC

An Organic Material For The Next Generation Of HVAC Technologies

Texas A&M researchers have enhanced the dehumidification efficiency of a polymer that could help develop more energy-efficient systems with a smaller carbon footprint.

today.tamu.edu

Can somebody check my video again and see if that "filtered" hygrometer on the right side was actually 18%? I may have discovered that I'm dyslexic and that reading was probably 81%. OH crap! I think I got it backward and the green saturated beads I've been seeing were orange and vice versa. *%$^ I may be dyslexic and color blind.

At the 55 second mark it was clearly at 18%.

 

[Squirrelmageddon]

At the 55 second mark it was clearly at 18%.

Awesome, I'm not dyslexic. Whew, I was worried about that for a minute.

 

[Humdinger]

@Squirrelmageddon let's assume for the sake of this discussion that zeolite desiccant actually works at the input side. The reason dive compressors use zeolite after the water separator instead of before it is so the water separator can remove 99% of the moisture. The zeolite is there to catch that last bit of moisture that the water separator misses. Zeolite is almost impossible to recharge in a home oven because it requires several hours of baking at higher termparatures than home ovens can reach. Silica gel beads can be easily recharged in a home oven at 200 degrees F for 15 minutes laid out in a flat pan.
So even if what everyone is telling you is wrong and your input filter actually is working, it is not a good idea to waste zeolite removing the bulk of the moisture in the air before the water separator can do its job.