How does one knows the filter is working? Will the filter be wet to the touch or no water will be coming out of the release valve?
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New GX filter is coming out!
- Thread starter 1900colt
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What a great question!
I too would like the answer.
Before attaching the new filter, opening the bleed valve on theCS-4 would release air & water.
Now, in my use of the new filter so far, I have not seen any water exiting the filter when I release pressure as per manufacturer 's instructions.
Needless to say, this is not very confidence inducing
Especially so when the relative humidity is 75% or greater
Perhaps I am doing something wrong.
But I sure would like the certainty of knowing the filter is working
Edward
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The only real way to know this or any of the filters on the market are actually working would be to fill a pressure vessel and send it off to be tested at a lab. I’ve looked into it a little bit and there are different tests with varying prices depending on the depth of data you want. It wasn’t exactly cheap from what I remember either.
I guess one could also fill their guns for extended periods of time and check the tanks for evidence of moisture collecting inside. That takes longer I suppose. Guess we have to sort of at least believe some of the marketing.
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I believe for our needs; just some physics:
At +200b, water is separated from the air and on the bottom of the tank.
If there’s no water from the outlet valve- everything is collected prior to separator.
ATB
S.
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If you open the bottom vent of the filter first, before opening the vent of the compressor, you will see water if you've run the compressor long enough and the humidity is high enough. I've only used my GX filter on my CS2 so far and I just filled guns with it. That takes about 5 minutes and I think I saw water vapor when I opened the bottom filter vent the last time. But it was not a large gush of water like I get from my Yong Heng after 5 minutes. But the Yong Heng compresses a lot more air in 5 minutes so it's logical the amount of water would be less. The air coming out will be dry as long as the filter is designed properly (I think it is) and you have not left the dessicant in there too long and let it get saturated. It seems to be designed to condense as much water as possible and trap any remaining moisture in the dessicant. I think that explains the relatively high mass and the space between the metal dessicant container and the pressure vessel surrounding it. I don't totally understand the logic of trapping the air in the filter until the pressure rises to 1500 psi but I think at least part of the logic is to allow more time for water to be separated. That should help but after the pressure in the filter goes above 1500 the air should flow through normally and that would be most of the air put into the gun. But there could be more to it than that.
I may try my GX filter on my Yong Heng. I saw a little water in the airtube of my P35-25 when I had it apart recently. That has never happened before so I'm wondering if my other filter is not as effective as it seemed to be. I've had these guns apart many times, however, and this was the first time I saw a few drops of water (and no damage to the gun). Anyway, I will be really surprised if I don't see a good sized gush of condensate from the filter vent of the GX filter.
One way of looking for water is to weigh the filter cartridge with the dessicant after you've used it awhile versus the extra one in the box. If it has trapped moisture it will be heavier. It would be nice to know how much it can trap before it gets saturated. That would allow us to know when it needs to be replaced.
I have not been doing this but I should. I have the "extra" filter on my CS2 first before the GX filter. It is similar to the filter that came with my YH. The YH gets oil into that filter and I change it after each bottle fill. I did one today. It was moist but water did not drip out. I could check the extra filter of the CS2 the same way. I have looked at it and it isn't seeing visible lubricant but if it's trapping moisture of any significance it should be apparent if you pull it and squeeze it. But the GX filter in my setup only sees what gets past the cotton filter. Which logically won't be a lot. My YH setup has the filters above the compressor so moisture drains back to the YH where I vent it. All indications are the venting gets most of the moisture.
I may try my GX filter on my Yong Heng. I saw a little water in the airtube of my P35-25 when I had it apart recently. That has never happened before so I'm wondering if my other filter is not as effective as it seemed to be. I've had these guns apart many times, however, and this was the first time I saw a few drops of water (and no damage to the gun). Anyway, I will be really surprised if I don't see a good sized gush of condensate from the filter vent of the GX filter.
One way of looking for water is to weigh the filter cartridge with the dessicant after you've used it awhile versus the extra one in the box. If it has trapped moisture it will be heavier. It would be nice to know how much it can trap before it gets saturated. That would allow us to know when it needs to be replaced.
I have not been doing this but I should. I have the "extra" filter on my CS2 first before the GX filter. It is similar to the filter that came with my YH. The YH gets oil into that filter and I change it after each bottle fill. I did one today. It was moist but water did not drip out. I could check the extra filter of the CS2 the same way. I have looked at it and it isn't seeing visible lubricant but if it's trapping moisture of any significance it should be apparent if you pull it and squeeze it. But the GX filter in my setup only sees what gets past the cotton filter. Which logically won't be a lot. My YH setup has the filters above the compressor so moisture drains back to the YH where I vent it. All indications are the venting gets most of the moisture.
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I plan to buy 13X color changing molecular sieve and cotton ends from Amazon when the time comes. MS can be regenerated, but takes a lot of heat to do so, so may just buy in bulk and discard.
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Ran my E5K2 with the GX filter the other day for about 16 minutes to top off my 9L SCBA from 240 bar to 310 bar. Bled a fair amount of moisture from BOTH the filter and the compresor at 11 minutes. My environment was about 90° F and about 58% RH. YMMV
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I'm not sure I follow your logic....
The same can be said for pressurized air at 9 bar in a standard air compressor.
What matters most is what your RH is.
if you think a GX compressor is "trapping" all the water from the air it moves, you'd be wrong. Even if you're bleeding every 10 minutes, moisture is STILL being pushed thru to your bottle.
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RH is totally irrelevant, on HIGH PRESSURES ABOVE 200bar.
To understand that, some knowledge of physics is needed.
Or, you can always ask AI what happens with moistured air when pressurized to mentioned pressure.
Here’s link and screenshot
ATB
S.
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The ambient relative humidity is a way to state how much water is in the air. At 1 bar, the pressure we live at (with adjustment for elevation) the oxygen in the air holds the water. But when our compressors raise the pressure of the air, the oxygen can no longer carry the water along. So it comes out. The relative humidity tells us something about how much will come out but it is not the reason the water comes out. It is the pressure. The higher the pressure the less water the oxygen can hold. But it is not quite this easy because of temperature. The compressor also raises the temperature of the air. That allows the oxygen to hold more moisture. But the temperature falls as the air travels towards the gun or tank. As the temperature falls, water comes out. I arrange my filter and lines to slope back towards the compressor so this condensation can be vented. What doesn't condense gets trapped in the filters, at least I hope it does. Short runs help the gun or bottle not get water because the lines stay cooler and the water is more easily separated and removed. If the air is relatively hot going into the bottle the chances it still has water in it go up. It will condense as the air cools.
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This is the phase diagram of H2O and it explains correlation between temperature and pressure.
In our everyday use with pcp compressors and tanks- we can hardly get to the critical point where water becomes supercritical fluid (where it’s both- fluid & vapor).
As long as we don’t fill our tanks before we raise the pressure to +200b- I believe it’s safe to say we’ll be good.
Risk considering that subject comes with oils and scuba use and I think it’s always a healthy risk, so not directly a security concern.
Also, putting molecular sieve in GS separator won’t help us much, because it will collect moisture when pressure is low (and still getting to the point where moisture can be separated by GXS combined with high pressure), so it will change it’s color from moisture that would be separated just a minute later.
I’m sorry if I can’t explain it with my limited knowledge of English.
i believe we only need a mechanical filtration at the exit valve of GX separator and if we use one small pre-filter before GXS (like I do with my YH) - it’s really only to make us calmer, not much more. Physics do its job.
Then again, what I know… no one got hurt from extra caution.
ATB
S.
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That's a nice graph to explain the temperature and pressure at which water changes phases but it doesn't tell us anything I can see about moisture coming out of the air we compress. 101kPa is 1 atmosphere (or very close to it) and 22,089 KPa is about 3200 psi. 100 C is the boiling point of water at one atmosphere as shown on the graph. 3200 psi is not high enough to address the desired state of my bottle or gun air chamber.
In compressed air we are not changing the phase of the water. It is vapor carried by the oxygen in the air. The water did not get in the air from boiling, it got there through evaporation which the graph does not seem to address. The question is how much water can the air hold at the desired pressure. The amount decreases with pressure and increases with temperature. But at room temperature it decreases as we raise pressure. So unless the air we feed the compressor is very, very, dry, moisture will come out as we compress the air. It might not come out until the air gets back to ambient temperature but when I run my YH in the summer, it comes out even though the air temperature is higher than room temperature initially. I know because I see it when I vent the YH. If we do not separate the water from the air it will be in our bottle or our gun. That is not what we want. Since the air at the compressor outlet has higher than room temperature, we need to either drop the air temperature to room temperature while capturing any water than condenses and/or expose the air to dessicant which will extract some of the water. Putting the GX air filter into the freezer until you are ready to use it will make it more effective for at least a little while because it will condense more moisture out of the air until it warms up. If we use our airgun in the winter outside where the temperature is lower we need the air to be even drier since the ability of the air to hold moisture will decrease as the gun cools.
In compressed air we are not changing the phase of the water. It is vapor carried by the oxygen in the air. The water did not get in the air from boiling, it got there through evaporation which the graph does not seem to address. The question is how much water can the air hold at the desired pressure. The amount decreases with pressure and increases with temperature. But at room temperature it decreases as we raise pressure. So unless the air we feed the compressor is very, very, dry, moisture will come out as we compress the air. It might not come out until the air gets back to ambient temperature but when I run my YH in the summer, it comes out even though the air temperature is higher than room temperature initially. I know because I see it when I vent the YH. If we do not separate the water from the air it will be in our bottle or our gun. That is not what we want. Since the air at the compressor outlet has higher than room temperature, we need to either drop the air temperature to room temperature while capturing any water than condenses and/or expose the air to dessicant which will extract some of the water. Putting the GX air filter into the freezer until you are ready to use it will make it more effective for at least a little while because it will condense more moisture out of the air until it warms up. If we use our airgun in the winter outside where the temperature is lower we need the air to be even drier since the ability of the air to hold moisture will decrease as the gun cools.
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Yes, we wanna separate moisture from the pumped air. Yes, on higher temperatures it will be harder aka higher pressure will be needed, but we as pcp people are achieving needed pressures every day.
If we have half decent setup- our compressors won’t go to extreme temperatures and +200b pressure will be perfectly fine to separate moisture.
And yes, moisture is just water in different state, nothing less and nothing more.
With exception of different oils in traces of moisture vapor, but generally we won’t have any problems with that.
So, put mechanical pre-filter after your compressor, put separator, position it vertically, put your bottle above your setup and open the bottle when pressure RISES ABOVE 200bar(AND ONLY THEN) and no molecular sieve will be needed.
Mechanical pre-filter of cotton/synthetic pads or sponge or similar can be dried and used again, same goes for GXS material. No further cost needed.
ATB
S.
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