# Air power switches supply question



## mickey (Jan 28, 2009)

The more I read and think about it, I may want to consider air power for switches. However, I don't want to have a separate compressor/tank outside just for this. I do have a big craftsman unit in the garage for lots of things that would have plenty enough to deal with this. Only issue is distance to layout. I do have a couple ways to get a line to the layout underground. The easiest is a 2" PVC tube that only has a yellow pex propane line that just happens to go from and to where I need it. The only issue is that it is probably maybe 150ish feet just to get to the central manifold area. Assuming I can fish it with the gas line already in it, which was a pain in th ass as it was, what size airline would be needed to get the necessary pressures to operate things?


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## Totalwrecker (Feb 26, 2009)

Try Greg Elmasian (sp?) site I know he uses air power and probably has your answers. A link to his site is in his signature here, easily found in the DCC forum.... 

My guess would be 1/4" irrigation line... but remember, the older I get the less I know. 

Happy Rails 

John


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## JackM (Jul 29, 2008)

My experience is only with the Sunset Valley pneumatic system which uses a very small hose hardly bigger than thick spaghetti, about 1/8 inch in diameter. Your PEX line should be big enough to take sufficient pressure to your manifold area. I'd expect you'd put in a regulator at that point to bring pressure down to what you need to operate the individual actuators for each turnout.

SV recommends about 30 psi which I found to be sufficient to power for my SV and A/C turnouts. I have a small "pancake" compressor in my basement. I regulate its output, then run about 30 feet of that little hose to the manifolds inside my control box.












I use some of the SV manifolds to direct the air to the individual actuators, which have output tubes running back down the control stand to the individual turnouts.

SV's recommended 30 psi was fine for me the first year, but then I added a turnout an additional 20 feet to the left and found that 30 psi wasn't enough to operate that particular unit. This year I've been running the system at 40 psi and everything works just fine, including the longer distance.

If you look just to the right of the bottom of the control stand you can see a bunch of the brown SV hoses. So far they've proved to be very durable and able to take a fair amount of abuse. The hose running from compressor to outdoors runs thru a vent in a glass-block basement window. The vent is normally closed, squeezing the hose, but it shows no sign of damage. It might be the reason I have to run at 40 psi. It's a very sturdy system.

JackM


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## Gary Armitstead (Jan 2, 2008)

Paul Burch on this site, uses Sunset Valley's air system. You might contact him for advice. At the moment, I am still building my layout and have a dozen turnouts that will be operated by the SV air system.


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## JackM (Jul 29, 2008)

I trust you didn't mean that I'm NOT on this site?









JackM


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## Treeman (Jan 6, 2008)

The volume of air needed to operate a turn out is very small. So supply line needed would be small.


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## Gary Armitstead (Jan 2, 2008)

Posted By JackM on 05 Aug 2012 12:05 PM 
I trust you didn't mean that I'm NOT on this site?









JackM
Say WHAT?!!!!







Wasn't even talking to you! This was for the OP mickey! Geeesh! Sure gotta cover your a** around here lately.


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## Mike Reilley (Jan 2, 2008)

Greg's GRR has the compressor in his shop at the front of his house...with a small air tube running from the compressor to an accumulator tank that is next to the valve manifold....maybe 130'. A small tube means like one 1/8" in diameter. You need the accumulator near your valves...and put a pressure gauge there so you know you have pressure. That's the trick.


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## Paul Burch (Jan 2, 2008)

I don't think the size of the tubing will matter all that much since we are not talking a constant air flow. My compessor and storage tank are in the garage with a couple 1/8 lines that run out to the layout and manifolds. I would keep a minimum 40lbs pressure. The older air system from Caifornia & Oregon Coast required 40 minimum. My original install has been in use now for about eight years and some newer stuff from Sunset Valley that has been in for about a year and a half. It all works great.


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## Dr Rivet (Jan 5, 2008)

Some folks just charge up a small portable air tank and bring it to the layout. The line to the control panel ends up being only a few feet.


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## docwatsonva (Jan 2, 2008)

Here's the system I have used for many years. It is a cheap Harbor Freight 5 gal. tank and a couple of regulators. It lasts forever with one filling.











Doc


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## Gary Armitstead (Jan 2, 2008)

Posted By docwatsonva on 05 Aug 2012 04:45 PM 
Here's the system I have used for many years. It is a cheap Harbor Freight 5 gal. tank and a couple of regulators. It lasts forever with one filling.











Doc
What a great set-up!







!


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## JackM (Jul 29, 2008)

Posted By JackM on 05 Aug 2012 12:05 PM 

I trust you didn't mean that I'm NOT on this site? 

JackM 
Say WHAT?!!!! Wasn't even talking to you! This was for the OP mickey! Geeesh! Sure gotta cover your a** around here lately. 


Forgive me if I'm being oversensitive. My post was also directed at Mickey. I don't know how else to interpret your posting that someone who is "on this site" has the same equipment that I had writen about twenty minutes earlier. As a paying member for a few years, I would like to think that I am also "on this site". 

And, of course, I added the smiley face to indicate it was just a friendly "dig". 

JackM


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## Gary Armitstead (Jan 2, 2008)

Posted By JackM on 05 Aug 2012 05:18 PM 
Posted By JackM on 05 Aug 2012 12:05 PM 

I trust you didn't mean that I'm NOT on this site? 

JackM 
Say WHAT?!!!! Wasn't even talking to you! This was for the OP mickey! Geeesh! Sure gotta cover your a** around here lately.


Forgive me if I'm being oversensitive. My post was also directed at Mickey. I don't know how else to interpret your posting that someone who is "on this site" has the same equipment that I had writen about twenty minutes earlier. As a paying member for a few years, I would like to think that I am also "on this site". 

And, of course, I added the smiley face to indicate it was just a friendly "dig". 

JackM JackM,

I have also been a paying member for 11 years and YEAH, you are over-sensitive. Deal with it.







Hey, I do like your set-up for the air on your turnouts, as well as Paul's and Doc's. It's good to get advice from as many folks as possible.









BTW, that's NOT a smiley face in YOUR post, sir. Looks more like a perplexed face to me and anybody else. How 'bout we get back on "track" to the original poster's question.


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## Paul Burch (Jan 2, 2008)

This is what I have done. There are three boxes around the layout similiar to this. Two of them have what amounts to three way toggles that plumb just like you would a three way light switch so the trurnouts can be operated from either side of the layout.
The air lines are in the conduit which is set in concrete to hold everything in place. Automotive tape for the track diagram.


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## Michael Glavin (Jan 2, 2009)

I’d use 1/4 “polypropylene tubing, some tubing is better than others specification wise as expected. I’d suggest the stuff used on semi truck airlines. If I recall its DOT rated togehter with higher temp and pressure ratings than the typical store bought stuff, its reasonably priced and available everywhere. Push-lok fittings are well suited for this type of product. I use the aforementioned tubing around steam heated equipment at 100psi typically without issue. 

Best results would be obtained by charging the 150’ of tubing with a pressure higher than required at the demand. A water-filter/regulator installed at the demand manifold reduced to 40psi would be ideal.

A local storage tank is great idea but not required with the low demands of our air-op switches, I’ll qualify my assertion by adding it’s not required with a properly designed air supply system. 

I know what you mean about fishing your PVC………

One might consider what the results would be with failure modes of the PEX tubing and a compressed air supply too! 

FWIW: Propane gas accumulates in puddles as its heavier than air.

Michael


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## mickey (Jan 28, 2009)

I guess I didn't make my question clear. I know I can get a small compressor or tote a small tank, but the more crap I have to mess with toting out to run, the less likely I will do it often. Do to location, I will have to tote locos and cars as it is. So I want to have the air line run from garage so it's live all the time. I already have a dryer in the garage, but adding a pressure gauge at the outside end of the supply line is a good idea. Will have power there all the time too, so just a matter of bring out locos and run. The pex i was talking about that is already in the 2" PVC conduit already is used for propane for grill, etc. I will have to fish and pull a new AIR line thru the same PVC. With turns and length, pulling a secondary line after the fact is usually a pain in the rear. The bigger it is, the more difficult. Knowing you loose pressure with length (just like with water), the question is how much bigger, if at all, the 150' main supply line needs to be from compressor to main manifold. Pulling a 1/4" nylon (like what is used for ice makers in refrig) will be a whole lot easier than pulling a 3/8" line. So is a 1/4" running 150' gonna give enough pressure to work. I guess I should call the Sunset Valley folkes.


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## Greg Elmassian (Jan 3, 2008)

you only need the 1/8 inch line, and then an accumulator nearer your switches... they don't use much air, but response will be slow w/o a local accumulator. I made mine from a one foot section of 4 inch pvc pipe and 2 plastic end caps, in a few minutes. 

With significant lengths from the compressor, bigger tubing won't help until you get up over 1/2 inch... 

Do what I did and read up on my site, has pictures of everything, under track and switches category. 


Greg


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## JackM (Jul 29, 2008)

Gary - 

Agreed! 

JackM


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## Greg Elmassian (Jan 3, 2008)

link to my page: *http://www.elmassian.com...trong>**








*


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## hi-railer (Jun 15, 2010)

Hopefully I can help on this a little. I am in the industrial hydraulic and pneumatic industry. 

The first place to start is the end component air requirements. I have not researched the parts discussed so I'm talking in general. See what is the CFM requirement and at what pressure. The fact that the toggle switch he has on his web site is clippard tells me this is very small stuff. In the industrial world we consider this mini-pneumatics. Any compressor should work fine unless you contiually hit the switch.

Keep in mind that Hose is called out by inside diameter(id) 99% of the time. Tubing is called out by outside diameter(od)always and often comes in different size id's for the same od.
A simple rule we use in hydraulics is every time you go up a line size your flow rate approximately doubles. I don't have charts for sizes this small but I would imagine the same holds true. If you are looking at charts for pressure drop and you use 1/4 x 1/8 tubing make sure you figure the 1/8" id for your figures. 

Line length does cause pressure drop as stated. Fittings and bends all have pressure drops. A long radius bend has less pressure drop than a tight radius and two 45's have less pressure drop than one 90. Nylon tubing(used for D.O.T. apps)generally has the highest pressure rating and will probably outlast the other plastics. Regardless of the tubing you use not every tubing is compatible with every fitting type. 

I would use mini flow controls at or near the switches. This would allow you to tune each switch to actuate at about the same speed. An example would be one switch with 10 ft of tubing and one with 200 ft. There could be a noticable difference in speed, adjusting the flow controls would allow them to be the same.


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## hi-railer (Jun 15, 2010)

There was one more thing I wanted to clear up. Adding a larger pipe manifold down the line is not an accumulator. An accumulator has another source of energy absorption or storage. Usually a spring, common for a shock absorber in a system, or a nitrogen charged bladder, common for an energy storage application. I suppose the air chamber in a water plumbing system would be the simplest form of an accumulator. 

Adding the manifold does help a pneumatic system in one way......It adds storage capacity. there is a simple way to explain it. The more tank capacity the system has the more cycles it can perform before the compressor needs to turn on. The trade off is it takes longer for the compressor to recover full pressure. Using larger tubing or hose helps accomplish the same thing.


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## Greg Elmassian (Jan 3, 2008)

Yep, well what would you call the device then? Happy to use the right terminology. 

No way I could move the compressor, and running larger line 130 foot was not an option, needed to keep it as small as possible. Without the "whatever" throwing switches was slow, after adding it was immediate. So it sure works well. 

Greg


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