RIX SA3. How to monitor the filter stack

[rob.mwpropane]

That’s at ambient pressure and freezing to super hot we’re talking modest changes in temp and, at pressure. At scuba pressures we’re talking grains per lb.

I understand, but it's a pretty substantial difference. Only pumping when ambient temps are lower makes a lot of sense on paper (to me). For instance, my filter is rated at 13,000 cf @ 80F OR 20,000 cf @ 68F. That's a pretty significant difference and technically means that going lower than 68F will yield even more from the filter. Just between those two temps alone is the difference of filling 70 HP 100's from empty to full. For me that's quite a bit of diving.

Just for anyone following those temps are what the filter "see's", so it would need to be 50F-55F ambient to get the rated 20,000 cf because the filter stack would get heat bleeding from the compressor (which can be anywhere from 10F-18F depending on compressor and where you get your information)..

The problem is how to monitor it. There is no good reliable way to monitor the moisture vs the cost of cartridges so the recommendations are based off worst case, 95 ambient and the loss of cartridge life is ultimately worth it given all the other costs involved. Most cartridges give excellent output vs cost so hours are the best indicator to go by. If you are keeping the ambient extra low and wanted to risk using cartridges longer, I guess it wouldn’t be that risky but for the cost of a cartridge, doesn’t seem worth the savings.

I am only using the compressor for my personal use, I am fortunate in the fact that I live in a somewhat cooler climate in the North East. I can choose to fill tanks / bank bottles on cooler days. I monitor with the spreadsheet. I set a timer when I start the compressor and stop it when done, always rounding up to the nearest 15 min segment.

I understand this wouldn't really work for a shop, especially in a warmer climate, but it works for me (they'll just replace filters more often). Because I run it this way my filter lasts me for the better part of 2 years. Because it's a Rix I'm only really concerned about moisture as there is no oil in the compressor. Even at the 18 month mark when i changed my last filter 1/2 of the moisture indicator strip hadn't turned yet (I don't know how accurate they are so I changed it anyway).

My tanks are always dry when I open them, and this works out to about $27 / year in filters.

So there is a sight-glass type gizmo (H20 Visual Indicator) that is supposed to change color when moisture is detected. For the Rix, am I safe in monitoring that and if it doesn't turn color, I should be good?

View attachment 803487

I have one installed. I never look at it. I really need to pull it out and get it blue again. If you do get one (wouldn't hurt) and it does turn from blue to white you can use a hair dryer or equivalent to change it back an re-use, no need to buy multiples. They last for years (so I've been told).

Get the 10 / 20 / 30 don't get the 20 / 40 / 60, they're worthless. With the 10/20/30 you'd want to change filters as soon as you see any change, but it should really be your last resort hail mary effort. Hours on the filter or the spreadsheet should be your 1st line of defense (but I guess it's nice to have some sort of sanity check in line). I have my setup pretty much exactly as it is in the diagram.

Moisture Indicator Disk - August Industries Inc.

This moisture indicating disc is for our visual indicators as well as many others. This disc is designed to show the relative humidity in a progressive scale. As 10 percent relative humidity is reached, the pie shaped section marked “10” will change color to pink. The same for 20 and 30. This...

www.augustindustries.com

 

[Gone for diving]

I understand this wouldn't really work for a shop, especially in a warmer climate

I always have thought that pulling the air from underground would be quite nice, or even just out of the basement...

Anyone that has looked at a air condioner knows how much water is in the air on a hot humid day. Just put a bucket under it.


It is amazing how much more efficient my hydraulic booster is in the fall compared to a hot summer day,
The amount of cycles to fill the same tank is noticeable less, (denser air molecules)

And yes I try to pump when its cooler, and even in the evenings.
Less humidity and more efficient.

Unearthing the lowly earth tube - Plumbing & HVAC

What do the high-and-mighty, and lowly ground dwellers have in common? They both understand the simple physics of managing air temperatures, with help from Mother Earth.

plumbingandhvac.ca

 

[happy-diver]

If you weigh your filter empty and weigh it full, the number in between is how much oil and moisture you can have

after that when you change your filter is up to your experience

 

[rob.mwpropane]

I always have thought that pulling the air from underground would be quite nice, or even just out of the basement...

Anyone that has looked at a air condioner knows how much water is in the air on a hot humid day. Just put a bucket under it.


It is amazing how much more efficient my hydraulic booster is in the fall compared to a hot summer day,
The amount of cycles to fill the same tank is noticeable less, (denser air molecules)

And yes I try to pump when its cooler, and even in the evenings.
Less humidity lower temp and more efficient.

Unearthing the lowly earth tube - Plumbing & HVAC

What do the high-and-mighty, and lowly ground dwellers have in common? They both understand the simple physics of managing air temperatures, with help from Mother Earth.

plumbingandhvac.ca

My concern with pulling from a basement is how much CO2 there would be? I honestly don't know. I would "think" the ideal would be a source of fresh air brought into a conditioned space to lower the temp. Personally I just have an extension that I put outside of the shop that brings fresh air in.

I "think" that humidity has little effect on compressors at all. It's been discussed on here, but when we're dealing with higher pressures regardless of the humidity in the ambient air we're still getting 100% RH right at the coalescers. The pressure will "wring out" the air. Based on my own experience I do see more moisture drained from the coealescers in the summer vs in the winter (so I drain more often), but I think that has more to do with temp than humidity. The PMV will squeeze out 99.3% of the moisture, but the temp of the incoming air would dictate how much moisture that air can hold.

I would rather have lower temps with 100% RH and 55F vs 45% RH and 70F (which is usually what our mornings here look like).

@Cio am I wrong at all in my understanding? I believe you work on compressors?

 

[Gone for diving]

I would rather have lower temps with 100% RH and 55F vs 45% RH and 70F (which is usually what our mornings here look like).

I guess I might be confused,
But cooler the air the less moisture it (can) hold,

That's what I thought.


I never really look at a gauge to see the humidity before I pump, but I know when it's a hot humid day vs a cooler humid day,

And my shop compressor sure makes more water in the tank, on hot days

 

[rob.mwpropane]

I guess I might be confused,
But cooler the air the less moisture it (can) hold,

That's what I thought.


I never really look at a gauge to see the humidity before I pump, but I know when it's a hot humid day vs a cooler humid day,

And my shop compressor sure makes more water in the tank, on hot days

You're correct, but some literature had me thinking in the beginning that humidity mattered... I just don't believe it does (at least not really). I don't care at all what the humidity is when I pump. I start by bleeding colescers every 10 min (Rix says 20 but I don't like that). If there's not a lot of moisture I'll bump my alarm up to 15 min.

 

[Gone for diving]

I "think" that humidity has little effect on compressors at all

Interesting. Probably not noticeable...

But should have a cooling effect in the cylinder/piston, especially the first stage,

Kinda like water injection on puller tractors,

I still say temperature/density of the air going in has a fairly noticeable effect on efficiency.....

Think, setting jets on a carb for different temperatures, and altitude,

 

[rob.mwpropane]

I guess I might be confused,
But cooler the air the less moisture it (can) hold,

That's what I thought.


I never really look at a gauge to see the humidity before I pump, but I know when it's a hot humid day vs a cooler humid day,

And my shop compressor sure makes more water in the tank, on hot days

Ah.. I see what you said and maybe the misunderstanding. Maybe this will help. If ambient is 55f @ 100% RH vs 70f @ 45% RH the compressor will still see 100% RH by the time it reaches the coalescers / filter. RH doesn't matter, in the end only temperature does.

Does that make better sense? This is not my area of expertise, but we have had this discussions on here before (with people much smarter then me) and that's what I took away from it.

 

[rob.mwpropane]

Interesting. Probably not noticeable...

But should have a cooling effect in the cylinder/piston, especially the first stage,

Kinda like water injection on puller tractors,

I still say temperature/density of the air going in has a fairly noticeable effect on efficiency.....

Think, setting jets on a carb for different temperatures, and altitude,

That has not been my experience. Of the 3 times that I measured filter temp after running for an hour I got anywhere from 9-11° over ambient, regardless what RH was.

Humidity in the compressor is always the same... 100%. Always. The only difference is what the temp is and how much that specific temp air can hold.

 

[rob.mwpropane]

@iain/hsm might have better clarification if he's around?