[AT] Air lines for shop

Brad Loomis brad.loomis at gmail.com
Mon Sep 13 13:46:36 PDT 2021


Last place I worked the dryers, either chiller or coalaesers were right
after the compressors, within 20 feet. Storage tanks were wherever was
convenient. But the system, all air lines were connected for redundancy,
was 2-150hp, 2-75hp, 1-200hp, and during harvest we rented an additional
350hp. Grape presses use a ton of air. We had 11. Storage was 4-1500 gallon
tanks. When opened every 5 years, required by California, they were as
clean as new. But we did have one place where a 2" line that ran
underground would condense and could blow out 10 gallons of water every
couple of days at the separator ahead of the press. All the dryers had auto
drains but I'd blow them off on my rounds and get 3-5 gallons of water
every couple of days. Paso Robles, CA isn't generally that humid. Lines
were all copper. Miles.
Water is invasive. Not undefeatable, but difficult.

On Mon, Sep 13, 2021 at 12:49 PM Stephen Offiler <soffiler at gmail.com> wrote:

> Craig:   Agreed.  Elsewhere I mentioned my workplace had an older 25HP
> compressor fail (pump seized) earlier this year.  We just got the
> replacement installed a couple of weeks ago.  The new one is a rotary, and
> the pump/motor just sit on a stand, no tank attached.  It happens that we
> already had a separate 200-gal tank integrated to the old system, just for
> surge capacity, so we're good.  We were advised, as you said, to plumb from
> the compressor to the tank and from there out to the chillers, but that's
> not how the previous system was set up and thus far we haven't had the
> plumbers in to correct it yet, so, at present we are temporarily running
> from compressor straight to chillers and then into tank.  And sure enough.
> it's not working very well.  We joke that we've got "pressure washers" at
> each of our blow-gun drops.
>
> On Mon, Sep 13, 2021 at 3:08 PM craig.warner47346 at frontier.com <
> craig.warner47346 at frontier.com> wrote:
>
>> At my business, we were advised to run the air from the compressor to the
>> receiving tank then to the dryer which exited to the compressed air piping.
>> The reason that we were given was that running it into the tank give the
>> air a chance to cool off slightly and for some condensation to drop out
>> before the air hits the dryer. That allows the dryer to start with slightly
>> cooler/dryer air.
>>
>> On Monday, September 13, 2021, 02:23:00 PM EDT, Stephen Offiler <
>> soffiler at gmail.com> wrote:
>>
>>
>> I am not arguing your point, but just observing that a cooler installed
>> between the pump and the tank is not something you see every day unless
>> it's a factory-built unit in the form of a fan-cooled radiator.   These
>> don't have water drains, either.  Why try to keep water out of the tank?
>> Reduced tank corrosion comes to mind; anything else?  One problem with this
>> idea is that the air coming out of the pump is HOT.  Whatever cooler you
>> install has to be rated for high temperature.  I know I ran into this when
>> I was spec'ing the chiller I recently installed on my 5HP compressor at
>> work.  The ones I looked at all generally had low input air temp rating;
>> around 140F was max, and some were 120F.  I vaguely recall one rated for
>> 250F and the cost on that unit was easily double.  Just curious.
>>
>> SO
>>
>> On Mon, Sep 13, 2021 at 12:48 PM Henry Miller <hank at millerfarm.com>
>> wrote:
>>
>> If you are worried about water (and you are right to worry) put your
>> compressor as far from where air will be used as possible, and use a big
>> pipe close to the compressor.  You want the air to move very slow near the
>> compressor so as much water as possible drops out there.  Make sure you
>> properly take all the air off the top of your overhead pipe, and slope that
>> pipe to a drain.
>>
>> If possible put a air cooler with a drain between your tank and the pump:
>> keep the water out of the tank if possible.
>>
>> --
>>   Henry Miller
>>   hank at millerfarm.com
>>
>> On Mon, Sep 13, 2021, at 10:19, Spencer Yost wrote:
>> > One of the reasons I have been thinking copper is because here in the
>> > humid south, water in air lines is a problem.  You can not paint
>> without
>> > a desiccant filter for example. Nothing worse than seeing water
>> droplets
>> > coming out with your paint (been there done that).  One benefit I
>> > thought copper would have would be  to condense water quickly and
>> > earlier in the run; therefore water vapor would be less of an issue at
>> > the tool end(assuming I slant the lines to run back towards the
>> > compressor) and my tool-end water filters wouldn't fill up so fast.
>> >
>> > Anyone with experience with copper find this to be true?
>> >
>> > Also, copper is less than $1 per foot more expensive(3.46/ft vs
>> 2.69/ft)
>> > so for a run that will be less than 100' worth of pipe so I decided to
>> > not sweat (excuse the pun) the cost factor between black pipe and
>> copper
>> > and just go on the merits.
>> >
>> > While continuing to look around at various options and along the way I
>> > saw 1-1/2" black pipe at Lowes with an oddly specific PSI rating:
>> > 231PSI    I'm beginning to think Brice might be right and they are
>> using
>> > steam rating....
>> >
>> >
>> > Spencer
>> >
>> >
>> >
>> > On 9/13/21 9:55 AM, Stephen Offiler wrote:
>> > > Brice reminded me of something.  Now, it's been a while since I've
>> put
>> > > much thought into Schedule rating of pipe. Reviewing, the basic
>> > > definition is:  Schedule = Pressure/Stress.  Example:  Schedule 40
>> > > pipe at 1200 psi would have stress of 30 ksi developed in the walls.
>> > > That's why wall thickness increases with pipe diameter - larger
>> > > diameter means larger internal surface area means higher force for a
>> > > given pressure, so wall thickness is increased to fight the higher
>> > > forces and keep stress in the wall constant.    I pick the example
>> > > above because Schedule 40 Class A pipe has a yield stress rating of
>> 30
>> > > ksi.  (There is also a Class B which is somewhat stronger).   At 175
>> > > psi  your factor of safety is almost 7, which is quite large.  I'd
>> > > sleep well with this number as small as 4 - in other words, 300psi.
>> > > Of course there's additional considerations for the fittings and
>> > > whatnot, but as long as it's Schedule 40, there's really nothing to
>> > > worry about.
>> > >
>> > > That stuff at Lowe's claiming 150 psi.... I don't believe it.  The
>> > > people writing up the specs on their website are probably
>> minimum-wage
>> > > drones.  I would get ahold of a chart showing wall thickness vs pipe
>> > > diameter and measure the wall thickness right there in the store
>> (yeah
>> > > I do tend to travel with a caliper in my bag most of the time).
>> > > Dimensions alone would confirm if this "150 psi" stuff is actually
>> > > Schedule 40.
>> > >
>> > >  I know you don't really want to use black iron pipe but I like I
>> said
>> > > Brice sort of reminded me of how all this pressure rating stuff
>> > > works.  Of all the options, black pipe is certainly the most
>> > > old-school, antique-tractor appropriate. I'm not against the modern
>> > > materials and I would also seriously consider Pex, but not PVC.  I
>> can
>> > > solder copper way faster than I can screw together black pipe but
>> > > copper is pretty darn pricey these days.  In my own shop, the answer
>> > > is:  rubber hose.  I've never graduated past the portable compressor
>> > > to something big and stationary that lends itself to permanent
>> plumbing.
>> > >
>> > > SO
>> > >
>> > >
>> > >
>> > >
>> > >
>> > >
>> > > On Sat, Sep 11, 2021 at 11:43 AM Brice Adams <brice.adams at gmail.com>
>> > > wrote:
>> > >
>> > >     Spencer,
>> > >     Something tweaked my memory from plumbing the Huber about
>> > >     different pressure ratings for steam, air, and fluids with
>> > >     schedule 40 and 80 pipe.  The 150 psi may be the steam rating and
>> > >     the air rating is 34 to 6 times higher.
>> > >     Brice
>> > >
>> > >     On Sat, Sep 11, 2021 at 8:21 AM Ken Knierim
>> > >     <ken.knierim at gmail.com> wrote:
>> > >
>> > >         Go copper if you're comfortable with sweating it together. I
>> > >         did that after trying PVC for awhile. Got some AZ sun on the
>> > >         PVC and it blew out a couple times with sharp little shards
>> > >         flying around (doesn't survive impact damage well). I like the
>> > >         sound of PEX but again, sunlight is abundant here.
>> > >         My $0.02
>> > >         Ken in AZ
>> > >
>> > >         On Fri, Sep 10, 2021 at 6:43 PM Spencer Yost
>> > >         <spencer at rdfarms.com> wrote:
>> > >
>> > >             So I’m going to be making three new pipe runs from my air
>> > >             compressor. Previously I’ve just relied on hoses since the
>> > >             50 foot hose will reach everywhere in my shop.
>> > >
>> > >             It will consist of one long “trunk” run that will be
>> > >             nearly 40 feet, and then a few stub runs of anywhere from
>> > >             5’ to 15’
>> > >
>> > >             I was thinking about black pipe as that’s what I have used
>> > >             before. But I had no idea the common, affordable black
>> > >             pipe you find in hardware stores is only good to 150 psi.
>> > >             My compressor is two stage and is 175 psi:
>> > >
>> > >             3/4-in x 3-ft 150-PSI Black Iron Pipe
>> > >
>> https://www.lowes.com/pd/Southland-Pipe-3-4-in-x-3-ft-150-PSI-Black-Iron-Pipe/3371442
>> > >
>> > >             I guess I’m thinking about biting the bullet and going
>> > >             copper. I’d like to go with some of those really neat new
>> > >             aluminum systems but I could never afford that.
>> > >
>> > >             What are y’all think about copper? I know 3/4” copper is
>> > >             good to about 1000 psi.   It eliminates  the rust problem
>> > >             that eventually befalls all black steel pipe systems;
>> > >             which is kind of a plus.  As far as installation, I solder
>> > >             better than I cut threads :-)
>> > >
>> > >
>> > >
>> > >             Spencer
>> > >
>> > >
>> > >             Sent from my iPhone
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>> > >             AT at lists.antique-tractor.com
>> > >
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>> >
>> > --
>> > Spencer Yost
>> >
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