Idiots guide to compressor filtration

confidis said:
If I was to use just one silo after the dri Pak .tampon or filter pack ?
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The tampon silo is pointless after the dry pack because the air should already be to dry for a cotton filter to have any affect, so if I had to choose, I would choose the sieve silo.

I would use at least one small cotton filter before any sieve. If "saturated" air enters the sieve it will quickly "flood" it with an undesirable result.

Personally I would sell the twin silos and fit one of these before the dry pack or sell the drypack and use the silos.
 
Presumable despite filters some water vapor will find its way into a gun. Does that water find its way out or can it collect in a gun over time. Does anyone have experience of removing a bottle from a gun and discovering water inside.
 
Very useful advice, thanks. Also nice to know the Hills is still doing the business. Mine is one of the originals too and running a Hills filter system. So far I have seen no evidence of anything entering my rifles although I’ve only looked inside a Daystate LR90 cylinder and a Superten and rapid bottle. I also fill my bottle then use that to fill the rifles, I wasn’t really sure why but after reading the above glad I did.
Thanks again for the info, very informative.
 
I too still use one of the original Hills EC3000 compressor with the standard water separator. I've just stripped and overhauled an HW100T which has had over 13000 pellets through it and has been been filled exclusively from the Hill's compressor in recent years. As I don't use any filtration whatsoever other then the onboard water separator, I was quite surprised to see absolutely no evidence of water contamination anywhere in the gun - either in the form of wetness or corrosion. Although I accept the fact that compressing air will cause any water vapour in it to be released, It does make me wonder if all this filtration business is bit of an over reaction and absolutely necessary. I do think that keeping the gun higher than the air supply system is essential however.
 
shotaholic said:
I too still use one of the original Hills EC3000 compressor with the standard water separator. I've just stripped and overhauled an HW100T which has had over 13000 pellets through it and has been been filled exclusively from the Hill's compressor in recent years. As I don't use any filtration whatsoever other then the onboard water separator, I was quite surprised to see absolutely no evidence of water contamination anywhere in the gun - either in the form of wetness or corrosion. Although I accept the fact that compressing air will cause any water vapour in it to be released, It does make me wonder if all this filtration business is bit of an over reaction and absolutely necessary. I do think that keeping the gun higher than the air supply system is essential however.
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That’s really good to know as I’m sure by now any problems would have showed up. Yep I keep my rifle higher than my bottle too, just in case. Hopefully mine will carry on being ok then with that great big Hills filter attached to it 😂
 
shotaholic said:
I too still use one of the original Hills EC3000 compressor with the standard water separator. I've just stripped and overhauled an HW100T which has had over 13000 pellets through it and has been been filled exclusively from the Hill's compressor in recent years. As I don't use any filtration whatsoever other then the onboard water separator, I was quite surprised to see absolutely no evidence of water contamination anywhere in the gun - either in the form of wetness or corrosion. Although I accept the fact that compressing air will cause any water vapour in it to be released, It does make me wonder if all this filtration business is bit of an over reaction and absolutely necessary. I do think that keeping the gun higher than the air supply system is essential however.
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Your experience is valuable! I am of the opinion that for some unknown reason the water removal (Both droplets and RH drop) inherent in a PCP compressor is far better than we expect, so a lot of all this output filtering is of dubious value.
Evidence? I have some moisture sensing crystals in my cooled output filter- they have never changed colour, and if my compressor was giving out 100% RH and hot air the filter cooling would definitely cause condensation that would remain in the filter tube and change the crystal colour sooner or later.
I think I have figured out a way of actually testing for water content with a real measurement....
 
sagalout said:
I know there are some posts on filtration already, but perhaps a condensing the information may help the beginner.

Why is filtration necessary (or at least wise)?
Air in the atmosphere contains water as vapour. When the amount of that vapour gets to much, it falls out as rain. Temperature alters the amount of water vapour that air can hold, cold air hitting a warm surface sheds water as condensation (dew if the warm surface is grass).

Water does not compress. @BallisticBill said think of air like a sponge, when you squeeze it water falls out. Compression is squeezing, at 300 bar the air has been squeezed (compressed) to 1 300th of its original volume. The water vapour has not compressed so has changed from vapour to water and you don't want that in your gun.

The compressor can introduce oil and other contaminants to the compressed air, we don't really want these in our guns either.

How do we get all this water and oil out of the air going to the gun?
Most compressors have a water/oil separator at the output, these do a good job of separating the water droplets and oil from the air stream, the captured contents are drained via the drain screw (this release air at the current compressor pressure and flushes the contents). Draining the contents during a "long" compression session is a good idea.

The separator does not remove everything, so I add cotton filters that catch any large contaminants like water, dust, dirt, oil, small children, etc. Cotton doesn't make a good vapour filter so I follow the cotton filters with a molecular sieve. Molecular sieve is granules (think bigger than sand but smaller than BBs) designed by clever people, that has holes in it the same size as the water vapour molecules and the water vapour molecules fall into these holes and are held captive, thus drying the air even further.

More to follow........................
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Condensing the information, I can see what you did there 😂
 
Minty said:
When you fill your rifle you just have to make sure the bottle / compressor is on the floor and your rifle is above them. For example I rest mine across the arms of a chair to raise it so it’s high enough to be above the air supply.
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Gotcha. I do that anyway come to think of it. Well I hope I do 😂
 
sagalout said:
That would be great.
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I'll run the idea past you. Accurate weighing is the key thing.

1. My system path is Compressor -Water separator, Hose, Nose filter, 1st filter, 2nd filter, Hose, Gun.
The 1st filter is a tampon type to primarily remove water droplets.
But the "Nose" of this also has room for another small cylinder of cotton wool.
I'd "slice" this into 2 even smaller, parts, First,(tiny) then a filter paper separator, then second- the rest of the nose space.
The first is to pick up the traces of oil that I see. The second to grab any water droplets that escape the compressor.
This second is then pretty well the first filtering substance seen. I can weigh this to 0.001 gramme accuracy, also the first oil filter and the separator and the first tampon filter that follows.

2. In my system, water vapour may be present in the warm ai coming out of the compressor, but as I cool the filter below zero, some of this may well condense in Filter 1 or 2. So when air flows in or out of the filter nose end, real water may reach this area and would be stopped. However, the candidate for stopping most of this when depressurising would be the first tampon filter.

3. Assemble.
4. Check Air temp and RH (To be used for Water IN) Fill 5 guns in normal way. Calculate the total Air Volume that has passed, and from Temp and RH, the total water that has reached the compressor input A.
5. Strip the filters and reweigh. Any extra has to be water =B. We hope for a very small figure.
6. When depressurising it would also be nice to try and catch/weigh the exhaust water. =C.

if A=B+C , that is a strong indication/check that the measurements are good, but pointless to do if B is very small or zero.
 
@colinb, read that a few times 🤯. I think I got it. Be very interesting to see the results, but I'm dubious about the accuracy of the data gathered.

RH: my cheap aliexpress RH gauges can't agree with each other.
Temperature: my cheap aliexpress thermometers can't agree with each other.
Volume of air passed: will a few bar or seconds difference between each fill skew the calculations?
 
sagalout said:
The tampon silo is pointless after the dry pack because the air should already be to dry for a cotton filter to have any affect, so if I had to choose, I would choose the sieve silo.

I would use at least one small cotton filter before any sieve. If "saturated" air enters the sieve it will quickly "flood" it with an undesirable result.

Personally I would sell the twin silos and fit one of these before the dry pack or sell the drypack and use the silos.
Click to expand...
Thanks
 
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