Air line question

[gustafson]

i used copper, and regular solder, in 2003, no problems. I drained back towards the tank so there is one place for water removal. I also did not make the drops point down. IF you assemble the T with the drop pointing down the water will always drain into the drop instead of going by. IF you make it point out or up[which would require one more elbow per] the water can run by the drop and not try to fill it. Each drop has a ball valve and a 1/4 pipe female for a quick disconnect.

I bought a cheap chinese refrigerated drier, it did ok. Got given a ZEK that is now installed between the compressor and the tank. Holy crap that thing works.
Zero water in the tank or the lines ever. Like 4 years now.

 

[Mud]

Other than a hydrualic hose, what would be some cost effective ways to have a flex hose form the compressor to dryer. Stay in 3/4" size.

I'm using a piece of 1" pushlock hose.

 

[AlfaGTA]

Had an air system running with a 10HP Atlas "V" twin recip. Auto drain on the tank, Water drops at all outlets with manual drains.
Pipe work, copper, silver soldered and sloping back to the compressor.
Installed a Soda blaster. Could not keep the darn thing working. Soda constantly clogging at the regulating valve for flow....Tried water traps, filters the lot, could not solve the issue.

Junked the compressor, installed a Kaeser "Aircenter", unit compressor with tank and refrigerated air dryer.....Oil filter on the tank outlet, auto tank drain (never opens , tank is dry)
Noise level in the shop dropped significantly and best of all the problems of moisture in the soda blaster simply disappeared.
Think much of the design for an air system can be done by treating the air at the source, not later....Refrigerated air dryer as the air enters the tank will solve lots of design issues...

Cheers Ross

 

[johfoster]

PVC for airlines is comparable to riding a motorcycle without a helmet. Lots of folks do it, and It works fine until it doesn't. I've seen it shatter, without pressure and with pressure, I won't use it.

I'd emphasize drying at the tank outlet, and the rest of the shop will stay dry, without any air collecting in the lines to be disgorged later.

x2 on both of these points.

I had pvc airlines in my shop long ago, and I would've also said it was working just fine...until it didn't and a blowout along the ceiling sent an 18" section of pipe across the shop. I will NEVER use pvc for air ever again. I have some black iron, and some copper now. The aluminum/hdpe rapid-air products are priced well, and that's what I recommend using.

You referenced having a dryer after the compressor. That is the only way to really get dry air, the separators only separate out condensed water droplets moisture can still pass. (refrigerated dryers work the same, but first chill the air to heavily condense the moisture) I would put my efforts into stopping the moisture before it even gets into the system, and then not worry about it. If you are not using an actual refrigerated and/or desiccant air dryer post compressor then I would follow others advice to build the system with drops and slopes to trap out condensate as best as possible.

 

[WizardOfBoz]

I hear alot to not use pvc, but we have pvc air lines here, and the other place I worked part time. I think this shop has been here for about 4-5 years and no "blowouts" that I know of....

I think not using pvc is a little thing, use whatever IMO. But yes, put a drop for a water trap/catch or whatever they call it.

"I've played Russian Roulette 3 or 4 times. Never had any problem. I'd say you're ok to play Russian Roulette"

Your logic fails several tests of logic, one of which is the n=1 problem. You are only looking at one data point (your shop). When a lot of shops are considered, its clear that there's a pretty good risk of catastrophic piping failure (PVC fails in catastrophic mode: you don't get a a warning, everything is fine and normal, and then suddenly there's a 5 inch shard of pipe through your eye). As Mud points out, "It works great until it doesn't". PVC and CPVC are fine for moderate pressure (e.g. water system) incompressible liquid service. For higher pressures of air systems, given that air is compressible, the air in the line contains too much energy and PVC and CPVC are unsafe. Using either is essentially a third-world, short-cut oriented, "Who cares if the workers are injured" approach.

Quincy knows a bit about air piping. They do sell their own air line product, but their site has this to say:

"You can’t use just any plastic pipes for compressed air distribution. The most common types of plastic pipe available today are polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC). These are widely used for plumbing applications but are not suitable for high-pressure systems, such as compressed air channels, because they cannot withstand the pressure.

Acrylonitrile butadiene styrene (ABS) is a good material for piping compressed air. You can find ABS in a variety of products, from car fenders to Lego brand toy bricks. Polyethylene (PE) piping is also produced specifically for compressed air systems. Another suitable plastic for compressed air pipes is high-density polyethylene (HDPE).

The early attempts to use PVC and CPVC caused a number of catastrophes, resulting in the Occupational Safety and Health Administration (OSHA) banning them for use in high-pressure systems. However, ABS, PE and HDPE are all OSHA-approved for compressed air piping."

The "PVC pipe has been safe so far" reminds me of:
"Every Friday for 20 years I've had 5 or 10 beers and some shots with the boys and have driven the 15 miles home from the bar without incident. Go ahead and do this IMO"
"I've smoked in bed for 50 years of my adult life and have never had a problem. Go ahead and do this IMO"
"I've had sex with hundreds of different people, without protection, and never had a really serious venereal disease. Go ahead and do this IMO".

There's a reason why OSHA banned PVC and CPVC for air lines. Guys that have seen PVC failures (Mud, johfoster) won't get near it. No one should.

 

[GENERALDISARRAY]

Like Sunlight? No plastic can withstand sunlight.

I have had Pex in my shop for over ten years and I have not seen any degradation?

I have a 180' run of it direct buried for almost 8 years.

I know of a large shop here that has big copper trunks with pex drops for the machines.

 

[leeko]

I couldn't tell from your original post - you may already know this. But... If your dryer is right next to your compressor, it will likely be quite inefficient at drying the hot wet air as it comes out of the tank. It's best to put some distance between the tank and the dryer, allowing the air to cool and water to condense out a bit before it hits the dryer. 10' is good, 20' is better

I'm no expert by any means, but that's what I've read and am planning to do for my shop

Lee

Sent from my SM-N960U using Tapatalk

 

[Bill Simmons]

Regarding using a hose other than hydraulic hose, you need to state what criteria you are looking for that would require a different hose type. I would use a hydraulic hose. They are readily available, will last for ever in this application and can be had with any fitting of your choice.

You did not state what you will be using for an air dryer. This could dictate what is needed down stream for additional moisture removal. Remember that the condensation occurs from warm air changing to cool air. And warm air changes to cool air where pressure drops. So if you have a regulator down stream of the dryer this is a point that may benefit from additional moisture removal.

Obviously most condensation occurs at the point of use as this creates a massive pressure reduction. It is too late to try to remove the moisture at this point.

Some benefit can be had from running your airlines where it is warm (after the dryer) as the delivered temperature will be higher. A hose laying on a cold floor is a bad idea. Also, if at any time you draw more air than your dryer is rated for that you will raise the moisture content of the air. So if you try to sanblast, you will very likely pull a large amount of moisture into your system.

I live where the humidity is low and so my experience is not highly applicable to your situation. I have 60 feet of underground copper pipe between my compressor receiver and my shop. I put a automatic water separator at the entry to the shop and another separator following the shop regulator. This solved all my moisture issues. The underground pipe does a great job condensing moisture and the first separator removes a lot of water. I also have a automatic drain on the compressor tank that cycles every time the compressor cycles.

 

[Djstorm100]

I've go a 80 gallons 5 hp dual compressor and a 30cfm dyer. The compressor is a 20cfm. The compressor is going to be outside my machining room. My shop is built in a warehouse, that my family owns. I have plan to put the dryer next to the compressor. I need to double check about having the compressor to close to the dryer. If the distance is a problem, I can take a air hose and coil it up (50ft) next to the compressor to give a greater distance before connecting it to the dryer. Just thinking out loud here. Problem I can see is the water will mostly just sit in the coil hose and not really have a way to get out?

Blue is the tank, it's not that big. The yellow is the dryer. I really want it out of my shop to give me more room but it looks like that won't be the case, if I need greater distance.

***Regarding the first post any comments on the shop layout options?***

 

[dsergison]

what were you going to do behind the mill? I know the electrical cabinet needs space to work in it... but VERY rarely. I just move my Fadal mill whenever I need to. I use 1.5" pipes and a super short portapower hydraulic cylinder. I only lift it 1/2" to slide pipes in place. It's a 1 person 20 minute job to move it 4 feet on pipes.

just an option to reclaim some work space.

I never take either of my EDM off the pipes I rolled them in on. They don't vibrate so I never bothered. I have a big space problem. It's like tetris.

 

[Mud]

Here's my setup. I have a 20 HP compressor with a 120 gallon tank outside the building. There's also a 7hp compressor with an 80 gallon tank inside. The 7hp is now just for backup, I left it in place and took the v belts off for OSHA purposes, and it's now a standby for emergencies and in case the big compressor needs service or repair. I use both tanks for storage, each one has a separate shutoff valve connection to the system, one is not routed through the other. From the shutoffs, a 1-1/4" line goes to a large Norgren water separator about 4' above the floor. From the separator a 1-1/4" line goes straight up to the top mounted inlet of a Hankisson dryer mounted at the 12' ceiling. From the dryer, a 1-1/4" line is teed to a full pressure line to the blasting cabinet and to a Norgren pressure regulator the feeds the shop supply loop of 3/4" pipe. The big norgren separator will collect 10 oz or so of water in a humid summertime week. The Dryer has a hose draining to the floor, we seldom see more than a 6' puddle under the drain hose, never a large accumulation. The rest of the system stays bone dry. The separator on the blasting cabinet stays dry now since the dryer went in, it used to need the drain valve cracked to a slow leak the entire time the cabinet was in use. The only other separators are on machines that the OEM installed, and they stay dry, or on jig grinding spindles, air drawbars and tools like that. They also all stay dry. I think the vertical run to the dryer helps condense water before the dryer, and the refrigerated dryer is the key to it all. I now consider that a necessity, I'm watching for a used one to pick up for a spare in case this one has a problem. they are expensive and worth every penny.

 

[johfoster]

I have plan to put the dryer next to the compressor. I need to double check about having the compressor to close to the dryer. If the distance is a problem, I can take a air hose and coil it up (50ft) next to the compressor to give a greater distance before connecting it to the dryer. Just thinking out loud

The screw compressors that I have owned all have the dryer mounted right on the tank from the factory, and in the past I had a refridgerated dryer hooked up right after the tank of a piston compressor and that always worked fine for me. I wouldn't think a coiled up rubber air hose would do much of anything for cooling the air, but maybe I am wrong. I would say it is not necessary anyhow from my experience.

 

[Djstorm100]

what were you going to do behind the mill? I know the electrical cabinet needs space to work in it... but VERY rarely. I just move my Fadal mill whenever I need to. I use 1.5" pipes and a super short portapower hydraulic cylinder. I only lift it 1/2" to slide pipes in place. It's a 1 person 20 minute job to move it 4 feet on pipes.

just an option to reclaim some work space.

I never take either of my EDM off the pipes I rolled them in on. They don't vibrate so I never bothered. I have a big space problem. It's like tetris.

Plan to put material that is waiting to be cut for the next job there and another tool box if need be.

 

[dkmc]

I wouldn't use PVC as it's cheap-ass. But shrapnel? Shattering? I've been in lots of shops with 'temporary' PVC lines that were still there 15 years later. When they break, they seem awfully harmless. Plastic at low velocity does not make a great projectile. I guess if you are in the habit of taking naps in the shop with your eyes open and placed against the PVC lines, it could cause you some discomfort if your eye happened to be exactly where the PVC line broke.

You are 100% wrong in your assumptions about the 'harmlessness' of said situation. I speak from witnessing PVC air piping failure in person on a couple different occasions. If you ever saw it in person, you wouldn't be making light of the potential and real danger.

 

[Djstorm100]

I just realize I can turn the mill 45 degrees roughly and have less wasted space, more room to roll engine hoist to pick up my 4th axi.

 

[EmGo]

Think much of the design for an air system can be done by treating the air at the source, not later....Refrigerated air dryer as the air enters the tank will solve lots of design issues...

In Kunshan (very humid) I moved the dryer from after the receiver to between the compressor and the receiver.

Made a huge difference. Absolutely agree with you, it makes no sense to store wet air, then try to dry it later.

 

[GregSY]

You are 100% wrong in your assumptions about the 'harmlessness' of said situation. I speak from witnessing PVC air piping failure in person on a couple different occasions. If you ever saw it in person, you wouldn't be making light of the potential and real danger.

As I said, I HAVE seen PVC fail on several occasions. It was harmless.
Post a link to a published incident of PVC shrapnel injuring someone.

 

[TeachMePlease]

As I said, I HAVE seen PVC fail on several occasions. It was harmless.
Post a link to a published incident of PVC shrapnel injuring someone.

Safety and Health Information Bulletins | The Use of Polyvinyl Chloride (PVC) Pipe in Above ground Installations | Occupational Safety and Health Administration

Here's lots.

 

[GregSY]

There is actually only one (1) incident where a person was actually injured, and was mentioned without any details as to the circumstances.

There is another incident mentioned where a pipe buried underground 'exploded' and made a crater 3 feet x 4 feet. Now...it sounds to me like someone must have buried a big-ass pipe with lots of CFM behind it to do that. As we know, bigger pipes handle pressure less well. Hardly the same as a 1/2" pipe running in a shop.

That whole report reads like some government hack trying to find ways to stay employed. It's short on facts and long on bombastic language.

I'm gonna put getting hurt by a PVC 'explosion' (more hyperbole) as possible. But less possible, and less likely, than having an airplane crash through the shop roof. That, too, can cause someone to get hurt.

 

[guest]

...I'm gonna put getting hurt by a PVC 'explosion' (more hyperbole) as possible. But less possible, and less likely, than having an airplane crash through the shop roof. That, too, can cause someone to get hurt.

A friend of mine once had a Cessna come through the wall right next to his machine- even that happens, lol.

What I mentioned before- I had 2 blowouts in 3 years on old PVC air lines. In both cases, the risk of injury was quite apparent to me, the shards were sharp as glass and no small number of them in each case.

The drip leg drain hit the floor with enough force to break the automatic drain off the bowl- I never did find all the pieces.

The 8' foot section that blew out went over a VF2, then over my CNC lathe, then over the dividing wall into the other side of the shop. It took a while for me to even find the broken section- I was searching in the vicinity of the failure, the missing section was clear on the other side of the building.

When it fails, it does so in a dramatic way.

For people who are using PVC, the most likely failure point is the fittings. Take a shop rag and wrap the fittings, and use cable ties to hold it. At least if they blow, you will have some chance of containment/reduction in the velocity of the flying shards.