What is wrong with this setup?! Any pointers?

[HoFFdog]

Hey guys

First off a big thanks to this forum and its members for being such a great source of ideas and inspiration for setting up my compressor workshop. All of the things i've done to try and ensure i get dry clean air has been taken directly from this forum.

Right. there are a few things i wanted to run by members of this forum about my modified set up/ I have uploaded photos so you can see.





The first question is regards 'check valves' or 'non return valves'. As you can see i have cut the air delivery pipe to run the output of the compressor pump through the condenser/rad and then back in to the receiver tank via a water trap. I decided to add an in line check valve after the initial U-bend right up near the head of the compressor pump with the idea being that any moisture condensing further up that run of pipe near the condenser wont work its way back inside the pump!





However, i'm now concerned that the check valve i have added (about 10" up from the compressor outlet) will interfere with how the main check valve mounted in to the receiver tank is able to unload the residual pressure via the pressure switch relief valve. I understand that normally this expels remaining pressure in the pump and delivery pipe so that the motor starts off load. But now the system will bleed off from my check valve and not from right up at the pump. Could this potentially damage my pump and should i remove this check valve??

I have also noticed that since doing this mod the pressure switch relief valve blows off pressure for a much longer time then before but i am assuming this is normal as it has all the pressure to drain from the the condenser and additional pipe??

Despite doing all this however and even tho quite a lot of moisture accumulates in the water trap after the condenser there is STILL quite a bit of moisture coming in to the receiver tank. Tho i must point out the only time i notice this is when it is very hot and humid outside.

To combat this i want to build & install and inline desiccant dryer. I am copying almost completely 'HAP's design featured in another thread. (I salute you sir )

I can buy a 40" length of 2" diameter copper pipe from my plumbing merchant. All i really want to know is this. I can either make one very long dryer from the whole 40" length placed on the main drop leg before my filter/reg OR cut it in two and have two smaller 20" dryers one placed immediately after the water trap after the condenser and the other on the main drop leg before the filter/reg as i would with the bigger length.

What would be better out of those two options in terms drying my air before it hits my gun????


Any help on any or all of my questions would be very much appreciated

 

[bob15]

I don't know why you're bothering with check valves.....seems pointless to me. Your air cooler (and fan) isn't big enough to be efficient for the size of your compressor. The tank on that will drain down so fast the compressor will run too much. The more it runs, the hotter the air will be, hence water.

Can you put your cooler in a tank of water?

Or, buy a bigger compressor?

 

[larry_g]

Couple of things I think I see there. Is the condenser up against the wall preventing cooling air from flowing THROUGH the fins and carrying away heat?

Your putting air into the top of the condenser and taking it out of the bottom. Any water that condenses will flow out the bottom and carry into your tank.. You need a place for the water to collect before it enters the receiver.

lg
no neat sig line

 

[HoFFdog]

I don't know why you're bothering with check valves.....seems pointless to me. Your air cooler (and fan) isn't big enough to be efficient for the size of your compressor. The tank on that will drain down so fast the compressor will run too much. The more it runs, the hotter the air will be, hence water.

Can you put your cooler in a tank of water?

Or, buy a bigger compressor?

I only put the check valve in near the head to prevent any condensed water accumulating back down the pipe and in to the pump, if indeed that were even likely to happen. There is a youtube video of a chap who has done the same and installed check valves.

I'm surprised you think the condenser/rad is too small for my compressor, that is a fair size old lump and is bigger than any car/truck rad and has 15mm copper pipe.

There isnt a way i can put it in water or buy a bigger compressor. The compressor is a 3HP 100l tank and pushed 14CFM. Just trying to make the best i can with what i got.

 

[HoFFdog]

Couple of things I think I see there. Is the condenser up against the wall preventing cooling air from flowing THROUGH the fins and carrying away heat?

Your putting air into the top of the condenser and taking it out of the bottom. Any water that condenses will flow out the bottom and carry into your tank.. You need a place for the water to collect before it enters the receiver.

lg
no neat sig line

Hi Larry

the cooler has is about 3" away from the wall so air can move around it.

As regards having a point at the bottom where water collects i was hoping that was what the water trap was doing. Do you think i should put a small drop leg with a ball valve just before the water trap then??

 

[bob15]

Have a look at these commercial dryers:

http://www.compressoraftercoolers.com/AirCooledAftercoolers/AA%20Aftercooler.pdf

http://resources.norgren.com/document_resources/USA/NCA-7Dryers.pdf

Refrigerated cooler:
http://www.industrialairpower.com/wp-content/uploads/Ingersoll-Rand-Non-Cycling-Refrigerated-Air-Dryers.pdf

If you note, the radiators are sealed to the fans with probably more passes through to cool the air. Your fan also might not be pushing enough air as well.

Another issue i see is that everything is very close together. Running a longer pipe, say 20', will allow for natural airline cooling as well (isn't 100% perfect, but it does help in cooling).


look at these GJ ideas:

http://www.garagejournal.com/forum/showthread.php?t=73032

http://www.garagejournal.com/forum/showthread.php?t=168005


bob

 

[xtremek]

If you note, the radiators are sealed to the fans with probably more passes through to cool the air. Your fan also might not be pushing enough air as well.

Another issue i see is that everything is very close together. Running a longer pipe, say 20', will allow for natural airline cooling as well (isn't 100% perfect, but it does help in cooling).

bob

^x2 shroud the fan if you want more efficient cooling. And if you look at cars again, the AC lines are always as long as they possibly can be and still fight under the hood. And I'd put drip legs everywhere. That being said, WOW, way cool.

 

[HoFFdog]

Thanks for your feedback so far guys

Originally the copper pipe system you see on the wall behind which consists of 3 drop legs and taps off through my filter & regulator to supply my tool & paint air lines, was on the opposite side of the workshop from the compressor/condenser. I used a 50ft 3/8" air hose to connect two together. I noticed quite a lot of pressure drop when running tools. Now that the two are situated together I've reduced the hose/pipe run by 50ft and tools/spray gun run much better.

I'm not able to expand much more than what I've done and dont want to add more pipe which is why I want to build the desiccant inline dryer the same as HAP. Pipe that diameter is expensive so I'm only going to buy a 1 meter length. Do you guys feel one long 1m dryer mounted right before my final filter/regulator would be better then building 2 x smaller 50cm dryers placed at different points a long the pipe run?????? Or doesn't any of this really matter?

 

[texasfiremedic]

What is your inlet and outlet temp of the cooler? The issue of the cooler being to close to the wall could be a problem (not enough air flow). Great idea with the radiator. It is better that nothing. How much water condensation are you getting from the cooler?

The check valve question. I would of used a spring check this will keep the valve closed under low to no pressure. It will not interfere with the bleed off of the compressor pump. The reason with spring checks, gravity checks only only do well with pressure against them. There is a possibility of the check not setting or holding under low or no pressure. This chance is slim but still there.

 

[HoFFdog]

What is your inlet and outlet temp of the cooler? The issue of the cooler being to close to the wall could be a problem (not enough air flow). Great idea with the radiator. It is better that nothing. How much water condensation are you getting from the cooler?

The check valve question. I would of used a spring check this will keep the valve closed under low to no pressure. It will not interfere with the bleed off of the compressor pump. The reason with spring checks, gravity checks only only do well with pressure against them. There is a possibility of the check not setting or holding under low or no pressure. This chance is slim but still there.

Hey Texasfiremedic. Thanks for tackling the check valve question. The check valve i have used is a standard 15mm non return check valve used in domestic plumbing that i picked up from Toolstation. http://www.toolstation.com/shop/Plumbing/Valves/Single+Check+Non+Return+Valve+15mm/d20/sd2696/p77952

The valve has a spring inside that holds a plastic cap in place to form a seal in one direction. Im assuming this is the same type of check valve your referring to.

Out of interest where would you of placed your check valves along the system and why?

As regards the temps from the inlet and outlet i haven't tested this exactly yet but there is a significant difference. The inlet i can barely touch it is very hot. On days where it isn't so humid the outlet felt almost fridge cold however on a very hot and humid day last week the out was warmer than this. I have moisture trap after the outlet which does accumulate moisture quite quickly but with the hot humid weather last week it just wasn't enough. Still a bit of water getting in the tank when i drained it.

 

[PT Doc]

Maybe placed a downward facing fan at the wall to ensure you are moving air behind the radiator.

 

[xekon]

I have done a lot of reading, for people that still end up with water in their tank because of insufficient cooling often the result of a small tank/compressor.

Ideally you would just get a bigger compressor, especially if there's a chance you will need the compressor for future jobs and its not just a one time thing for you.

One thing I have noticed in a couple of youtube videos is that if you add an additional tank to your system then the first tank will retain most if not all of the water, I am no expert, nor do I know if its safe to run your compressors in this manner, but it was an observation I made.

this guys video 1:

this guys video 2:

and this one:

 

[seber]

It will be far more efficient to let the air go directly to the storage tank and put your water removal equipment on the out line. Let the tank act as a cooler. If water in your tank is a problem for you, just add an auto drain.