Yong Heng questions (start to a FAQ?)

I hand pumpe for a year before getting a tank. Every time I did I would make sure that the gun was above the bottom of the pump. When bleeding after the fill I would always get wet fingers/hand from the BOV. That tells me the filter beads on the intake weren't doing much. Yes, you should use one, though I never found moisture inside the air tube of the gun. I think the slower rate of fill with the handpump keeps a lot of the moisture from entering the gun.

Centercut, did you include the high pressure and temperature in your calculations.inquiries about acid formation? Just wondering as I know chemical reactions that don't occur under normal atmospheres and temperatures can when heat, pressure, and friction are introduced.

Good point about the hand pump. I have one, but don't use it. I would think the slower rate of fill wouldn't get as much moisture, and that venting off moisture periodically would be sufficient. Do you get any moisture in the small filter that comes with the hand pump?

As far as temperature and pressure, I couldn't find any studies that show any significant acid formation from high pressure air with entrained moisture passing thru Zeolite beads. When removing the beads for inspection after ten to fifteen hours of use, I didn't see any moisture at all in the pressure tube. And lets be honest, even if there is some form of moisture inside the tube, it can be cleaned out when changing Zeolite, PLUS as I said, the aluminum is anodized. The point in the linked web site about channeling is moot, since that is a concern for high airflow compressors, and not so much for these small low flow compressors. Also, as I recommended, packing the Zeolite in tightly by filling enough so that the cotton tampon piece is compressed will result in a tightly packed Zeolite bed. I'd use the filter with the inlet lower than the outlet, so that the vent on the pump can blow off any water/oil entrained when you bleed air periodically during filling and keep it from collecting in the filter tube. Basically, just using common sense and "good engineering practice" should result in a safe and effective moisture removal system IMHO.

My Hill pump never came with an external output filter, but an small molecular sieve before the blow off valve. No worries on the other question. I would rather play it safe with a known product that has the sellers backing when it comes to high pressure components. It's a piece of mind thing.

Good input John. I think we're mainly looking at people that are interested in the Yong Heng style inexpensive air compressors. If you're inclined to purchase and operate one of those, there is no additional risk in using a Chinese air dryer (you can't "play it safe" with the Alpha air dryer while using a Yong Heng compressor ). For those that either can afford to or want a totally safe high pressure air compressor, I think a Bauer type compressor would be best, like the Utilus 10 or Junior II. They can be found used and in good shape for around $2500 if you look hard enough and long enough. Those compressors come with a built in air filter and dryer, and will last a lifetime with proper maintenance.

On air drying - I think another aspect is relative humidity. Got back from Mississippi a couple weeks ago, and if I were down there, I think drying air would be critical. 90 degrees and 90% humidity should generate quite a bit on condensation during compression.

On the other hand, I live in the desert where average humidity in my home is below 30%, usually closer to 25%. With the lower humidity, is the air drying equipment really necessary?

I think the heat generated by compressor will create water within the compressor.i not sure...

and the longer it runs I think that water would build up ...

Any of you engineering types, please chime in.
I know water is incompressible while air is compressible.
As air warms, it can hold more water vapor (Relative Humidity)

So, I think what’s happening is that the air is compressed, the incompressible water vapor precipitates out, forming droplets that drop down to the bottom of the cylinder or tank.

I think it was Centercut that told people if they buy a Yong Heng, there was a specific centrifugal feature to look for that had something to do with water extraction, though I was never really sure what it was. Does that fit this conversation anywhere?

Since the compressor has no tank, but only cylinders, would the water build up in the cylinders, or go directly to the tank?

Trying to learn here . . . . 

I think the water molecules will just be mixed in between the air molecules when the tank is filled gravity will let the water settle out. In the compressor the ail will compress the water in the air can’t compress so it will leave suspended in the air. I’ve seen ice form when damp compressed air is released to normal atmospheric pressure.
if there was away around not needing to greatly minimize the H20 in the air for compressing I think it would of been invented by now. I know it’s a pain but if you don’t do it you will cut short the life of the machinery and possibly the user.

You will always get water out of your HP air compressor. Even if your relative humidity is low. Water is basically incompressible. Air is obviously compressible. So if I take Air at normal pressure of 14.7 psi, and compress it to 4500 psi, I am compressing the air about 310 times. Hence 310 or so Bar, since each bar is one atmosphere. So now you have, as a percentage of air, about 310 times more water per volume than you did when you started, since the air compressed but the water didn’t. Make sense? That’s why we periodically vent off water that precipitates out of the air at the HP outlet and also use an air dryer to remove most of the water that hasn’t precipitated. For obvious reasons you don’t want to put humid air in your air tank or air gun. 
Mike 

"Centercut"You will always get water out of your HP air compressor. Even if your relative humidity is low. Water is basically incompressible. Air is obviously compressible. So if I take Air at normal pressure of 14.7 psi, and compress it to 4500 psi, I am compressing the air about 310 times. Hence 310 or so Bar, since each bar is one atmosphere. So now you have, as a percentage of air, about 310 times more water per volume than you did when you started, since the air compressed but the water didn’t. Make sense? That’s why we periodically vent off water that precipitates out of the air at the HP outlet and also use an air dryer to remove most of the water that hasn’t precipitated. For obvious reasons you don’t want to put humid air in your air tank or air gun. 
Mike

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OK, that explanation actually makes sense.

So, in our case, while living in a desert will reduce the relative humidity and the amount of water / liter of air, from (for example) 90% to 30%, the desert air at 30% will simply produce 1/3 the water of Mississippi air at 90% (assuming the same temperature). The desert air will precipitate water, just at a slower rate than the Mississippi air.

That also indicates that whether I used a compressor or hand pump, the results are the same as how the air is compressed doesn't matter, just the moisture in the air and the fact that it is compressed.

Also, thanks for the explanation of "Bar" as 1 atmosphere. I always worked in PSI, so understanding the relationship of Bar to PSI is important when looking at different guns and measurement systems.

If it's the only device on circuit and 20 amps or less I would use 12 gauge copper wire don't get aluminum.

I have one of these yong heng compressors, and im happy with mine.
1. 13 days to arrive at my front door from time of order.
2. 120V auto stop
3. 120V, cord about 3-4' long
4. Using the factory In-line filter, change it every 20 min of run time, or 2ish top offs on my bottle
5. 90 CI tank from airtanksforsell 3300-4500 psi in about 8min/ tops up 230 bar wildcat 22 in 45 seconds or so
6. Not really a problem but i like to fill my 4500 psi bottle to 4700ish psi, after the air in the bottle cools down she will read 4500 psi. The burst disc let go on mine at about 4500-4600 psi. No biggie, i just double up the burst disc and keep a closer eye on the presser gauge. Bottle is protected by 5200-5300 burst disc so i am comfortable Taking my bottle to 4700 psi.
7. 4 hours of run time, runs good
Hope this helps.

"Kayakairgun"I have one of these yong heng compressors, and im happy with mine.
1. 13 days to arrive at my front door from time of order.
2. 120V auto stop
3. 120V, cord about 3-4' long
4. Using the factory In-line filter, change it every 20 min of run time, or 2ish top offs on my bottle
5. 90 CI tank from airtanksforsell 3300-4500 psi in about 8min/ tops up 230 bar wildcat 22 in 45 seconds or so
6. Not really a problem but i like to fill my 4500 psi bottle to 4700ish psi, after the air in the bottle cools down she will read 4500 psi. The burst disc let go on mine at about 4500-4600 psi. No biggie, i just double up the burst disc and keep a closer eye on the presser gauge. Bottle is protected by 5200-5300 burst disc so i am comfortable Taking my bottle to 4700 psi.
7. 4 hours of run time, runs good
Hope this helps.

Click to expand...

I’m just curious what type of filter is the online filter in your set up . I have Carette compressor and I use the Alpha filter that Joe B sells with it. I’m a bit paranoid about getting moisture in my tanks were I may consider adding an effective inline filter to my setup.

Its the in-line filter that comes with the pump, not sure what the filter element is called but works for me. I filled the tank to 4500 psi, then dumped about 2000 psi from the tank onto a clean white paper napkin, was no oil or wet spots where left on the paper napkin. But i will most likely upgrade my filter to something better soon. 

I purchased a tuxing compressor which is similar. The 220v US plug was one for a regular 120v outlet they just made both flat prongs hot and no ground. Which works over seas but not the best for the US. I ended up removing the plug and wired in a cord directly to the terminals than put a 220v round plug on the end to match our electrical standard. It would be a bad idea to take a 120v outlet and make it 220v someone will get hurt and most outlets are not rated high enough.

Other than that it workes good. I would recommend buying the bag of rings for the pencil piston since they ware out and are easy to replace. 

It is loud also. 

very new to pcp airguns....I bought a yong heng, before I got my Benjamin marauder. this pump works very well so far, as I have filled my 90in tank about five times....it fills it from 3000 to 4500 psi in about 6 mins or so. this thing works great......peace, randy.

I just bought one of these yesterday, so well will see...it is to be here next week. I am looking at ~70 refills of my tanks to hit the break/brake even point....we will see how it does.

Everyone that actually owns one seems to day good things about it, the review that really tipped me over the edge is the sling shot guys review...he tore the thing down and it did look put together nice....we will see.

Don't make the mistake of Not getting a cartridge type filter similar to the alpha. Unless you live in a desert lack if a filter will rust your tanks and guns from the inside out. It may take a year but your gun will be ruined and if it blow you will be hurt. The cotton was filters with some carbon are useless
I know a lot if people ignore this accessory but it's needed when I buy used guns I always inspect the air storage tank and I usually need to replace it. If it's real bad I'll skip the gun completely as hidden internal corrosion is difficult to repair.
NOW TO REPEAT MY SELF THERE IS NO SAFE $300 COMPRESSOR UNLESS YOU ADD A CARTRIDGE FILTER.