Moisture trap location

[njaimo]

Wondering if I am worrying about nothing... My compressor, a DIY system, has the intake to the moisture trap higher (about 10") above the output of the compressor. Thus I am thinking that the compressor has to push condensed water in the output line all the way up to the moisture trap intake -- which does not seem optimal. Not quite sure what the implications are of having the line from the compressor to the moisture trap full of water.

I have the opportunity to reconfigure the setup and thinking of making it so the compressor output is higher than the moisture trap intake to allow easy drainage of water from the compressor's output.

Does this make sense ? or I am worrying about nothing ?

 

[tbone1004]

your pump isn't pushing liquid water, if it did you would know as hydro-lock is not a good thing and it tends to cause things to break rather quickly. It's just moving gas saturated with water around and that moisture then condenses and falls out in the water separator. The pump doesn't care whether it's 10" or 10ft above or below it.

 

[njaimo]

...thank you for the reply, though not sure I agree. What difference is there in the pressure conditions between the moisture trap, and the tubing leading from the compressor to the trap ? My guess is that the pressure in the tubing leading to the trap is pretty much the same as the pressure within the trap, so water will condense in the tubing as well.

Being that the trap inlet is higher, gravity would prevent water condensed in the tubing from flowing up, and as time passes and more water condenses from the air, the tubing would fill up with water, so air exiting the compressor would be bubbling up through the water in the line. I believe some compressors have moisture traps, or at least drains between stages, since it is pressure and temperature that defines when water condenses...?

 

[TrimixToo]

In my opinion, the trap should be below the cylinder it's plumbed from, in case the outlet valve ever leaks or there should be a generous drip loop in the line. That will prevent water from flowing into the cylinder after shutdown, helping reduce the potential for hydrolock and corrosion.

 

[NAM001]

...thank you for the reply, though not sure I agree. What difference is there in the pressure conditions between the moisture trap, and the tubing leading from the compressor to the trap ? My guess is that the pressure in the tubing leading to the trap is pretty much the same as the pressure within the trap, so water will condense in the tubing as well.

Being that the trap inlet is higher, gravity would prevent water condensed in the tubing from flowing up, and as time passes and more water condenses from the air, the tubing would fill up with water, so air exiting the compressor would be bubbling up through the water in the line. I believe some compressors have moisture traps, or at least drains between stages, since it is pressure and temperature that defines when water condenses...?

The smaller the line between the final compressor out and the mechanical moisure separator defines the gas flow rate through the piping. say 3 mph in a 1/4 line and 40 mph in a 1/8 line. If the flow rate is high enough,,, any condensation in the line will blow through to the separator. If to low it will puddle till it fills the line and then you get a slug of water shot to the separator. very crude example but that is how it works. Equally if you have a 1/2 " line coiled up as a cooler in a bucket of ice water. the larger the line the more cooling it gets but the more difficult it is to get water pushed to the separator. now in a 15 cuft pump it means nothing but in a 2 cu ft one it would. Either way I dont think you have a problem. It is better to have your concern with a mechanical separator than with a chemical dryer in a filter cartridge. You force the issue of draining the final compressor line every time you open the drain to the final mechanical separator. the drop in pressure from draining will draw most all the water in the line into the separator. To insure the piping is dry ??? purge the final separator when you finish with the last tank filling. Thats what I do. The separator pressure drops about 1000 psi when I finish a drain. the created 1000 Psi drop will vac out most anything form the piping The only other way to do this would be to have your final water separator physically lower than the compressor. Then it trickle drains to the separator. The probably may not be any improvement in doing that.

 

[RayfromTX]

^excellent answer sir^

 

[happy-diver]

in and out, up and down

round and round

oops

 

[njaimo]

Thanks for the replies !

KWS-- I agree with all you state and reinforces what I thought was going on. I can likely drain all water from the line by purging the trap at the end, however since I have a chance to modify I will put the trap intake below the compressor output so that as you say "The only other way to do this would be to have your final water separator physically lower than the compressor. Then it trickle drains to the separator.", which would seem to solve the problem to begin with, as TrimixToo seems to think as well.

Thank you all.

 

[rcontrera]

Criminy guys! You are all trying to out "SMART" each other on a very simple thing!

Moisture separators don't condense liquid out of the air. It mechanically knocks it out by use of radical direction changes. Any actual moisture in the lines will just blow through the lines. Don't believe that, pull your straw out of your drink and blow it in the face of the guy across from you. Once you pick yourself off the floor, you will realize that all pressures inside your compressor are higher than your breath and any moisture will just move on down the line or even up the line and overcome that evil gravity. If you have a moisture problem, it isn't from the height of the separator.

Now, fill your tanks and go diving!