Filtering the Input vs. the Output of the Compressor!

[357cal]

This topic, I feel, is one that rarely comes up, and it's the first time I've ever thought about it. Thank you for highlighting this important step for all of us. I will be using the Tuxing 4500 psi for an example if someone like myself wants to give this a try? At the bottom i will list the whys you would have one in place. pic 1) compressor. Pic 2) air intake Pic 3) diagram Pic 4) Parts list. pic 5) how to pic 6) final. Now for the why you would do so:

Air Intake Filter: Why It Matters​

An air intake filter does more than just keep bugs and dust out:

• Particle Filtration: It traps airborne debris, pollen, and fine dust before it enters the compressor. This protects internal components and reduces wear.
• Moisture Reduction: Some intake filters include desiccant or moisture-trapping media, helping reduce the humidity pulled into the system—especially useful in muggy environments.
• Cleaner Output Air: Less contamination at the intake means less work for downstream filters and separators, which is critical when you're trying to keep oil and water out of your tanks and slugs.

Muffler: What It Actually Does​

A muffler on the intake is primarily for:

• Noise Reduction: It quiets the suction noise during operation, which can be significant on high-RPM compressors.
• Minimal Filtration: Some mufflers have a basic foam or mesh screen, but they’re not designed to trap fine particles or moisture.

Real-World Trade-Off​

If you're running a Tuxing in a clean, dry indoor space, a muffler might be “good enough” for casual use. But for long-term reliability and cleaner air fills—especially if you're tethering or filling larger tanks—an intake filter is the smarter move. It’s like putting a good air filter on a tuned engine: not glamorous, but it protects your investment.

I hope it can help someone out, i will be using this to build mine at some point.

GerryR, THANK YOU.​

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[GerryR]

@357cal Very nice descriptive post!! Your welcome and thank you!

 

[karl_h]

A lot of things going on in the graph below, but it shows you will not(without extreme and very expensive measures) ever get enough water vapor out of ambient air prior to compressing to 300 bar. This is taken from a british government paper in 2006 when they were revamping their breathing air standards because their old standards left many cases where scuba/scba regulators were freezing up with water if their old standards were followed(nobody with brains by that time followed their old standards and hadn't for years/decades, governments everywhere are slow and stupid at best) You can find the paper if you search for HSE health and safety executive moisture levels in compressed breathing air. The curved lines are air at 100% relative humidity at the different pressures shown bottom right(1,40,200, and 300 BAR). The left hand axis is in celsius and is the dewpoint of the air along each curved lines at 100% relative humidity at each of the 4 pressures. The horizontal axis in the middle of the graph is only for 1 bar at the temp along the curve, it is mg per cubic meter of water vapor at that point of the top red lines temperature at 100%RH. If you follow that red curve to the left, it tapers off and ends at roughly negative 30C dew point for air at 1 bar, and the mg cubic meter is to fine to show on this scale, but is less than 2mg per cubic meter at 1 bar and 20C. I did the math years ago, that is less than 1 percent relative humidity at 20C 1 BAR, and that just gets you to somewhere north of 200 bar and south of 300 bar where that air compressed would be fully saturated with water vapor(100%RH). At 20 C and 300 bar the 100 percent saturation level is at a dew point of near negative 45C(again the scale is too large to get nice fine numbers out of it). If you are out hunting in the winter and it's not really that cold, say 10C, your pcp is filled to 300 bar and you have been out walking or sitting long enough it's temp has equalized, you need air inside it that is getting close to -60C dewpoint, that is much, much closer to 0% relative humidity at 20 deg C and 1 BAR than it is to 1% relative humidity at 20c/1bar. Within reason money wise, you are not going to achieve that on input air at 1 BAR. As @Centercut mentioned in the thread, you filter input air to put clean air in your compressor, not to take water out of it. I think only certain times of the year in certain locations you can find air dry enough to compress to 300 BAR with no water vapor filtration post compression in Antarctica and nowhere else on the face of the earth. If you are wealthy and don't mind wasting tons of money, you can reduce the water vapor in the air around you to that point and compress it without post compression removal of water vapor.

For those who love to say I have never seen water in my tank/tube so I'm good, if you do see water, you were so bad off it is not funny, The act of depressurizing a container at high pressure puts whatever small amt of condensed water vapor was there back to vapor long before the pressure has dropped to the point you can open your pressure vessel, IE: you won't see the water that may have been there if you haven't been feeding it proper dry air.

 

[GerryR]

I have put a lot of this information into a .doc file including some from the thread that @Jfk742 linked to, but the file is too big to download. I like to keep good info where I can get my hands on it easily. Who said what and the links to the threads are in the .doc file. It's not exhaustive, but I think the important stuff is there. If anyone wants a copy PM me with your contact info, and I'll email you a copy. Thanks to all for your inputs!

 

[Ta-Ta Toothie]

With the compressor I'm using, it's effective. Not perfect, but good enough for me. Just changed the media and recharging what was taken out.

 

[Ta-Ta Toothie]

I also use a post molecular sieve. I wouldn't just rely on the pre.