Air compressor/water separator question

[cdestuck]

I just purchased a new 60 gallon single stage air compressor and having a little questions as to a water separator. My air compressor is going to be under roof but on the exterior of my garage. As far as the placement of my water separator, I was thinking it would be proper to run an airline from the air compressor Through the garage wall and have my water separator there. Would that be the most logical thing to do as far as any freezing. I am here in central Pennsylvania, where the weather isn’t so bad but we do have periods of frigid temps.

As far as water separators, I was wondering how they exactly work. Do you drain them out periodically or I read something about does water run from them back down into the tank of the air compressor? This is all sort of new to me, but I know through you guys I’ll get it figured out.

I was sort of thinking about the kits you can buy on Amazon for plumbing these in with flexible pex blue pipe. Now I’m reading about this flexible aluminum coated pipe and I’m just wondering if they are that much better than the PEX pipe. Appreciate all your thoughts.

 

[908Jim]

You want to give the air as much time as possible to cool so moisture can condense and be separated out, so you would want your filter/separator to be as far from the compressor as possible, but still upstream of your first air line drop. If you are going to plumb a loop, you either use one before the loop starts, two before each drop on either direction, or at each point of use.

Generally, you want the piping to slightly slope back to the compressor tank so condensation in lines runs back to the tank where it would be drained when you drain the compressor tank.

Most separators need to be manually drained. If you buy from Wilkerson, ARO, SMC, Norgren, or other industrial brands, you can find some variations of drain styles.

Cant comment on the kits, but PEX pressure rating drops as temperature (compressed air is hot) goes up. Also unsure how it is affected by petroleum. I do know it is not rated for compressed gasses.

 

[ericm]

Some water separators unload the drain valve at low psi. So if you ever empty the line its in, the separator will unload and drain. But if you keep it pressurized you'll need to drain it another way. They make automatic tank drains that open at time intervals, maybe one of those could be adapted. Or a manual valve that you open periodically.

 

[metalmagpie]

Air as it comes out of the pump is hot and wet. Lots of guys these days are plumbing oil coolers into that air path between compressor pump and the tank. It goes pump - cooler - filter - tank. Those coolers take advantage of the air flow from the large air pump pulley/fans. These coolers have been reported to be very successful at cooling the air before it gets to the tank. I have not read nearly as much about how much water gets filtered out, but physics says that cooler air can hold less water, so it has to.

That's one type of cooler.

Another type of cooler is downstream of the compressor tank's output. This type is often seen as a serpentine array of copper pipe on a wall in an attempt to thermally couple the compressed air and the ambient shop air. In other words, to cool down the air from the tank. Again, the purpose is to condense the water from the compressed air. Such a cooler is always followed by a filter to remove water.

There are also refrigerated coolers, which can be fitted either between the pump and tank or between the tank and workpiece.

Then there are automatic tank drains. These have the purpose of removing water buildup from the tank in order to prolong the tank's life (because it won't rust through nearly as fast).

metalmagpie

 

[rdoty]

The main goal is to keep water out of your tank - and away from downstream consumers of air like sanders and spray guns.

Warm air can hold more moisture than cooler air. A cubic meter of air at 100 degrees and 80% humidity will hold more grams of water than the same cubic meter of air at the same 80% humidity and 50 degrees.

Air coming out of the compressor pump can be close to 300 degrees. When this air cools to room temperature a lot of water condenses out of it. Normally this water collects in the pressure tank.

If you insert an after cooler between the compressor pump and the pressure tank it will condense the excess water out of the air before it reaches the pressure tank. You will need a drip leg to keep the water out of the tank. If you attach an automatic drain valve to the drip leg it will drain the water before the drip leg fills. These automatic drain valves typically have a float that rises when water collects, allowing the water to exit through a drain port.

Do a search here on Garage Journal for after cooler and you will find multiple posts of how people have built them. Unfortunately these will tend to freeze up if they are exposed to below freezing temperatures.

 

[southalabama]

Dad used to paint compound bows for a local manufacturer. We had a small tank with desiccant beads mounted outside the paint booth. It was a long distance from the compressor. We had copper lines and various lifts and drops with drains along the way. The compressor tank had an automatic drain.

 

[Kaizen]

Congrats on your big air. I am further north and use one of these. Not cheap but i have it hosed into a plastic pretzel container with a hole in the lid for the drain hose. It needs ac power and kicks off at the time limit you set. As long as the end of the hose is not under water it can freeze and not be an issue. I also do have a small water seperator on my psi control and i have had that pop off if i don't make sure its drained manually in these temps.
Some of the cheaper 60 gallons can put out a lot more water then others. I used to have a husky one that when used in freezing temps would ice up my tools.

https://www.amazon.com/gp/product/B075H8K97T/?tag=atomicindus08-20

 

[BurtEggley]

I added extra hose before the trap, and drain the tank after each use. Even just draining it a little when done will blow out most of the water in the tank. In a perfect world you would dry the air before it goes into the tank and never have to deal with heavy rust. Keep in mind that oxygen is what rusts tanks, and that is present in the air you compress. As to the quality of air you will be using, the amount of drying depends on what you will be using the air for. If you need a small amount of really dry air once in awhile, say for minor painting or glass beading, you can add one of these or equal in addition to your normal dryer. It will take out the residual moisture. I catch 99% of the moisture by having a longer hose, then the filter traps. When I need all the moisture gone I add one of these inline.

https://www.amazon.com/Master-Disposable-Filters-Standard-Threads/dp/B0CSKQM68P/?tag=atomicindus08-20

I actually use this model but the price has gone way up. They used to be a couple dollars apiece. They can be reused once they dry. Harbor Freight has a clone for three or four dollars.

https://www.amazon.com/Motor-Guard-D-13-Disposable-Compressed/dp/B00YCM9BBG/?tag=atomicindus08-20

 

[1930artdeco]

The compressor I just got (a 41 Wayne), and it has a post cooling with copper lines wound around in a circle right behind the fly wheel. That copper tube goes straight into the tank. Is it worth creating additional cooling there or should I just add dryers and Seperators after the tank-which I plan to do anyways.

 

[imagineer]

Are you looking to buy something or make something?

If you're in the mood to make something, google search "Franzinator".

Whereas there are equal counts of folks out there that say they do or don't work, I for one can attest that the version I made does work and pulls a fair amount of moisture from the compressed air.

 

[john.k]

I used to drain up to 200 gallons of water every day ,took ages and you had to stand around or air would blow out making a excessive noise,and the manager would come running over ranting about air waste and the elctricity bill ........various kinds of water drains would work OK for a month or so ,then fail ,blocked by congealed. oil...steam traps ,low pressure releases ,nothing worked for long.

 

[72Anthony]

Water separators work by causing the air to spin in a sporal as it enters the device. The condensed water is heavier than air and the spinning droplets fall to the bottom.

It's similar to a cyclone on a dust collector.

Water separators have a drain at the bottom, can be manual or automatic.

It's best to put it before the tank to reduce the amount of water getting into the tank.

Be aware that a given separator has a minimum and maximum flow. Bigger isn't better in this case. If the separator is too large, the air velocity will decline and not as much water will fall out.

 

[john.k]

Also a big difference between a water separator ,refrigerated dryer and a dessicant dryer.

 

[yyc_ranger_4x4]

For the drains....I couldn't stand an automatic one always draining even though the pump wasn't running. I wired in a timer, and a normally closed valve in the drain of the tank, that triggers a 1 sec purge after the motor stops. No more wasted air/energy. When I built my intercooler, I also used a normally open valve that closes when the pump runs and acts as a pressure drain for between the pump/tank and a drain for the intercooler. Seems to work fairly well.

 

[72Anthony]

For the drains....I couldn't stand an automatic one always draining even though the pump wasn't running. I wired in a timer, and a normally closed valve in the drain of the tank, that triggers a 1 sec purge after the motor stops. No more wasted air/energy. When I built my intercooler, I also used a normally open valve that closes when the pump runs and acts as a pressure drain for between the pump/tank and a drain for the intercooler. Seems to work fairly well.

For the drains....I couldn't stand an automatic one always draining even though the pump wasn't running. I wired in a timer, and a normally closed valve in the drain of the tank, that triggers a 1 sec purge after the motor stops. No more wasted air/energy. When I built my intercooler, I also used a normally open valve that closes when the pump runs and acts as a pressure drain for between the pump/tank and a drain for the intercooler. Seems to work fairly well.

YYC,

Can you post some details of the valve and timer?

That system seems ideal for me since I don't use a ton of air.

 

[john.k]

When air expands it cools ,and holds less water vapor and the vapor condenses to drops ........a separator collects these drops ........its cannot remove water vapor that will condense further along the line ,or in your spraygun or air tool...........To avoid water drops altoghether ,you need a dryer ,usually a refrigeration plant that freezes the air to remove all water.