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Ahh..going back a few posts..
Okay, lets go back to compressors 101...
Start here.
Understanding SCUBA Compressors and Filtration
I quote you here and address these assumptions and questions below.
That is only changed by the Pressure Maintaining Valve setpoint and the ambient air temperature and the temperature rise on the filter. So I get 1/2 hour of filter life with no PMV and 128 hours if I set my PMV at 240 bar, my fill pressure. It is impossible to fill to 240 bar and maintain pressure over the filter at 1 bar. So if I tell it my PMV is set at 1900 psi/130 bar I get no credit for the time above that. I also think there is a chance the 13x would last longer than 1/2 hour into filling the first tank without a PMV.
In addition I don't see a way to adjust for ambient humidity. There almost has to be some gain from our dry desert air at 10-20% relative over 80-90% Mexico air unless the calculator is assuming the moisture trap gets either one to the same level???
That calculator is not screwy in all ,of my uses for it, it has proved extremely accurate.
Please remember I told you... of the fill stations tested, the VAST majority fail for MOISTURE !
A significant fact that you do not seem to understand is that ambient humidity plays NO PART IN THIS EQUATION. Once you start compressing air the air, water is squeezed out..hence we have inter stage moisture traps..I bet you if you supplied air to the compressor at 1% humidity and 20*C, you will see water coming out of the traps, not a lot....but there will be some....
Temperature rise in the FILTER is another misconception that I have researched with Swampdiver and we could find nothing to indicate that M.S. looses its effectiveness at any realistically expected temperatures.
It is the TEMPERATURE OF THE AIR GOING INTO THE SEPARATOR, which if cooler is denser and drops the moisture much more effectively.
I use lees than a gram of M.S. per tank fill in 33*C weather (Assuming 22.7% uptake of moisture by the m.s, so .22 g of moisture gets by my separators per fill.)...yes that means with a 33 inch tower holding 1.300 grams of m.s. I get OVER 1,200 fills. I use two final separators, chill the air, and don't think too much about filter changes.
I agree you get no "Credit" for the time above PMV set point, as it is inconsequential...run the numbers at a pmv pressue of 0, 10, 20, 30....bar and you will begin to see that the curve of the effect is flattening out and it is a case of diminishing returns and increased compressor wear.
I can say with some certainty that unless you are using some big ass filters, YOU WILL expend your filtration with no pmv VERY quickly.
I think you are making some serious assumptions here, that are likely outside of your knowledge..give it a try if you think it is wrong...how much water comes out of your final separator in 1/2 hour run ? Is it enough to saturate your M.S. ?
Remember m.s. is good for 22% by weight of adsoption before it is exhausted. If you have 500 G of M.S. and you get 100 cc of water out of your final separator in 1/2 hour..well there you go..it is finished. No back pressure and a whole lot of that moisture at 100% relative humidity is going into your filters...add the back pressure and you squeeze out a heck of a lot more water..now as the tank fills, it becomes its own PMV...so the effect is not THAT bad....maybe an hour, not a half hour to filter saturation.
I can put you in touch with a guy I helped here on the internet..all of his steel tanks were ruined...$10,000 because two 5 cent o-rings in his PMV failed and he did not know enough to catch and fix the problem.
This is why I have pressure gauges before and after my PMV...I can see it open and I can be 100% sure it works.
This is a whole lot of work for some small flash rust spots in your tanks and with no air test result, not even a report of a 10/20/30% moisture on your compressor...If all is as you say, your filters are too small or you are not changing them often enough..It IS that simple.
Okay, lets go back to compressors 101...
Start here.
Understanding SCUBA Compressors and Filtration
I quote you here and address these assumptions and questions below.
That is only changed by the Pressure Maintaining Valve setpoint and the ambient air temperature and the temperature rise on the filter. So I get 1/2 hour of filter life with no PMV and 128 hours if I set my PMV at 240 bar, my fill pressure. It is impossible to fill to 240 bar and maintain pressure over the filter at 1 bar. So if I tell it my PMV is set at 1900 psi/130 bar I get no credit for the time above that. I also think there is a chance the 13x would last longer than 1/2 hour into filling the first tank without a PMV.
In addition I don't see a way to adjust for ambient humidity. There almost has to be some gain from our dry desert air at 10-20% relative over 80-90% Mexico air unless the calculator is assuming the moisture trap gets either one to the same level???
That calculator is not screwy in all ,of my uses for it, it has proved extremely accurate.
Please remember I told you... of the fill stations tested, the VAST majority fail for MOISTURE !
A significant fact that you do not seem to understand is that ambient humidity plays NO PART IN THIS EQUATION. Once you start compressing air the air, water is squeezed out..hence we have inter stage moisture traps..I bet you if you supplied air to the compressor at 1% humidity and 20*C, you will see water coming out of the traps, not a lot....but there will be some....
Temperature rise in the FILTER is another misconception that I have researched with Swampdiver and we could find nothing to indicate that M.S. looses its effectiveness at any realistically expected temperatures.
It is the TEMPERATURE OF THE AIR GOING INTO THE SEPARATOR, which if cooler is denser and drops the moisture much more effectively.
I use lees than a gram of M.S. per tank fill in 33*C weather (Assuming 22.7% uptake of moisture by the m.s, so .22 g of moisture gets by my separators per fill.)...yes that means with a 33 inch tower holding 1.300 grams of m.s. I get OVER 1,200 fills. I use two final separators, chill the air, and don't think too much about filter changes.
I agree you get no "Credit" for the time above PMV set point, as it is inconsequential...run the numbers at a pmv pressue of 0, 10, 20, 30....bar and you will begin to see that the curve of the effect is flattening out and it is a case of diminishing returns and increased compressor wear.
I can say with some certainty that unless you are using some big ass filters, YOU WILL expend your filtration with no pmv VERY quickly.
I think you are making some serious assumptions here, that are likely outside of your knowledge..give it a try if you think it is wrong...how much water comes out of your final separator in 1/2 hour run ? Is it enough to saturate your M.S. ?
Remember m.s. is good for 22% by weight of adsoption before it is exhausted. If you have 500 G of M.S. and you get 100 cc of water out of your final separator in 1/2 hour..well there you go..it is finished. No back pressure and a whole lot of that moisture at 100% relative humidity is going into your filters...add the back pressure and you squeeze out a heck of a lot more water..now as the tank fills, it becomes its own PMV...so the effect is not THAT bad....maybe an hour, not a half hour to filter saturation.
I can put you in touch with a guy I helped here on the internet..all of his steel tanks were ruined...$10,000 because two 5 cent o-rings in his PMV failed and he did not know enough to catch and fix the problem.
This is why I have pressure gauges before and after my PMV...I can see it open and I can be 100% sure it works.
This is a whole lot of work for some small flash rust spots in your tanks and with no air test result, not even a report of a 10/20/30% moisture on your compressor...If all is as you say, your filters are too small or you are not changing them often enough..It IS that simple.