Flow Capacity

by Andrew
(Johnstown, PA, USA)

I hear a lot of guys running 1" or bigger piping throughout their garages for air supply from the compressor. However, most non-industrial filters, regulators, and lubricators aren't sized up to that large of pipe.


Is it pointless to run through a 1/2" F-R-L combo and then end up in a 1" main? Why go with such a big main if the smaller F-R-L is a bottleneck right after the compressor?

Thanks,
Andrew

_______________
Bill says....

If you take a 50 gallon compressed air tank, and put it through a special "squeegy machine" you might end up with a tank that is 1" in diameter and a few hundred feet long. My point is, the compressed air doesn't care the shape of the storage tank, yet when it comes to using air tools, having more pre-compressed air available is always better than not having lots of ready to use air.

As long as your end application can be adequately fed by the air that flows through the smallest bottleneck in the system, it's all good.

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Plumbing a compressor question.

Does air compressor system for air instrument need spillback line?

by kholish
(indonesia)

when the pressure of the air instrument system is achieved the setting target (i.e 7 bar), unloader valve will work. the result is dischard flow is much lower than minimum flow design. Plese tell me, do we need spillback line to prevent compressor surging ?

_______________________
Bill says...

I am not familiar with what you mean by a spillback line.

In order to reduce pressure surge in the air line to any application, the regulated pressure should be set below the cut in pressure level of the air compressor. This takes the pressure surge out of the line to the application.

Read the page on Regulators for more info.

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Plumbing a compressor question.

plumbing for Lincoln model #9101 unloader valve on two stage compressor.

by Larry Williams
(Lakeport,California)

I have a Lincoln model #9101 two stage compressor that has what I think is an unloader valve on the side of the compressor. There are three fitting that appear to take 1/4 inch copper tubing. One line goes from the valve to the head on the compressor.But I am not sure where to connect the two other lines.I have a pressure switch on the storage tank but it does not have a fitting for plumbing.I also am not sure if I need back flow valve's on the inlet pipe to the tank and one on the outlet side.Can you help me? Thank you.

______________________
Bill says...

Your request is posted Larry. Good luck! I hope you can find a Lincoln air compressor adviser via this site. I sure am not one.

As to the back flow valve, typical compressor configuration has the tank check valve located where the air from the pump enters the tank. So, you may already have one there.

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Plumbing a compressor question.

Air Line Sizing with Respect to Air Outlet Size on the Compressor

by Mark A.
(Chicago)

Hi,
I have a question relating to air-line / plumbing. In the air-lines page I read the quotes about small air lines causing turbulence and pressure robbing:
"There’s no such thing as too large a compressed air line. A common error in compressed air systems is line sizes too small for the desired air flow." And "Undersized piping restricts the flow and reduces the discharge pressure, thereby robbing the user of expensive compressed air power."
I am looking for a compressor that is roughly in the 3-5HP / 60Gal / <$1000 range. All of the compressors I have seen in this range have a 3/8” or 1/2” air outlet size. So my question is, doesn’t going from 1/2” to your filter / regulator / manifold and then out to like a 2” pipe cause quite a bit of pressure drop and turbulence? Why don’t the compressor manufacturers just make the air outlet ports like 3” and make the consumer downsize to whatever they may need?
From what I have read on this site I have no doubt that I have come to the right place for an answer! Look forward to hearing back,

--Mark

_____________________
Bill says...

Howdy Mark. Thanks for your kind words.

The discharge port size on a compressor is generally the right size to handle the maximum CFM rating of that compressor. Going bigger than that provides no benefit to the user, and increases, possibly, the cost to the compressor manufacturer.

In terms of air mains in a shop, you will have read that I'm a strong proponent for large storage, and remote compressed air storage to allow your compressed air time to cool and de-water naturally.

If you decide to plumb from a 1/2" discharge port on the compressor to a 2" air main, there will be some initial turbulence as the mains fill, but from then on, that will self limit. It depends on the CFM requirements of the tool being used as to how fast that 3" main is drawn down, the same for the compressor tank, and the frequency with which the compressor cuts in as a result.

I don't know how much 2" pipe you are considering, but instead of looking at it just as a pipe, consider it as a longitudinal air tank.

Bigger is better, especially if you are hoping to power high demand air tools.

Hope this helps.

Cheers,

Bill



Comments for Air Line Sizing with Respect to Air Outlet Size on the Compressor

Click here to add your own comments

Jan 06, 2011
Thanks Bill
by: Mark A.

Bill,
Just what I expected - a concise well phrased answer. Thanks again for all you have written on the subject of compressed air! I plan on buying your ebook before going any further with my design, but first I need the weather to get a bit nicer here in Chicago. Thanks again,

--Mark

______________

Yeah, I've heard, and seen, that the windy city is just that, and in the winter it is @#%#$%$ cold. You have a great waterfront. I have enjoyed walking it a number of times.

Much welcome, I'm sure.

Bill


Click here to add your own comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Plumbing a compressor question.

compressor discharge plumbing - which way is best...

by john kali
(succasunna,new jersey .USA)

should the plumbing for a 150 hp screw compressor be from the air compressor to the air drier to the air receiver tank to the compressed air user or should the plumbing be from the air compressor to the air receiver tank to the air drier to the compressed air user and why?

______________________
Bill says...

Hi John. "Should" is a matter for the experts, and the drier folks should tell you how they prefer the plumbing.

If yours was mine, and I had the real estate, I would plumb to the biggest reservoir I had room for (assuming you are talking about a plant air supply) to allow lots of dwell time in the storage tank for the air to cool and naturally de-water before I sent the air on to the drier.

The why is that the lower the moisture load going into the drier the less it has to work, and that saves money and, depending on the type of drier, the media.

Make sure your reservoir has an auto drain that runs often enough, and for long enough, to keep the reservoir empty of water.

My two cents worth. :-)

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Plumbing a compressor question.

plumbing shop air

by chuck
(michigan)

when plumbing the main supply is it a good idea to make a complete loop to keep air flow even all the way around the system? Then make your drops off from this loop?

__________________
Bill says...

Absolutely. If you look at all of the pages on this site that refer to this subject, you will see that they all agree with you.

The "ring" should slope slightly to one corner so that all the water can run to that point and then into a drop line with a drain.

Make sure to take all of the other drops off the top of the main so the water can't flow down into them.

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Plumbing a compressor question.

plumbing pipe size

by William Bodnar
(Redlands,CA)

Are you supposed to step the size of the pipe down from the compressor to the drop downs. I have a shop with about 200ft of main air supply and 6 10ft drop down pipes. I had a old compressor from the 60s and out of the compressor had a 3/4 in pipe for the main then stepped down to 5/8 in and everything worked well. I am having a bran new compressor and dryier installed. out of the compressor and dryier looks lik 1/2 in pipe then it steps up to the 5/8 in pipe again. is this right?

____________________
Bill says...

William... it's common for air lines to step down in size as the compressed air plumbing approaches the end application.

For example, with an air tool, it is often a recoil type air hose that is used, so the tool is moveable, and these are commonly sized smaller than the drop line.

The only downside to lowering the plumbing size is that you are restricting the flow of air somewhat. However, if you are feeding an air tool with a 1/4" inlet port with air from a 1/2" air line, you should not be concerned about the air supply being strangled by the plumbing.

My rule of thumb is to keep the compressed air pipe size as large as my budget and location will allow. Aside from cost, there is no down side to having larger rather than smaller air lines.

In fact, the main air line in many plants is 3" or 4" in diameter and that size of pipe, coupled with the long run, equals quite a nice supply of ready to used compressed air that doesn't, any more, have to travel all the way from the compressor to the point of use, each time the air tool is turned on.

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Plumbing a compressor question.

can i solder my copper lines on my air compesser

by paul
(jamestown nd)

can i solder my copper lines on my air compesser

____________
Bill says...

Sure, if they are copper. One of the nicest installations I've ever seen for an air system was all sweated (soldered) copper, with a couple of unions at strategic places to allow the copper pipe to be disassembled, should that be necessary.

On my compressed air plumbing pages I talk about this quite a bit. Copper is a great air line. No rust, little issues with maintenance, good burst resistance etc.

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Plumbing a compressor question.

Plumbing my new 8 HP Honda driven compressor

by Joe Grippi
(Englewood, Florida)

I have a new 8 HP Honda driven 19 CFM air compressor that will be mounted at the front end of my f350 Ford truck bed, which will service two 15 gallon horizontal wing tanks mounted over my wheel wells, and also service another 30 gallon vertical tank positioned on my wash rig about 12 feet from the compressor itself.......I would like to know the best way maximize this volume via the plumbing between these air units......

I should mention, that there will be times that the truck is remote from the trailer, where I would have both wing tanks operating at 30 gallons, other times, with trailer, I would want all connected together to work with the full 60 gallons of storage......Any help in sizing these interconnecting lines and valves would be greatly appreciated.....Joe Grippi

_________________
Bill says...

Hi Joe:

It were me, I'd go with 3/4" good quality rubber / vinyl hose. Remember, hose is measured on the I.D.

I don't know the geometry of the layout, other than as you have described, but I have no doubt that with a selection of couplers, connectors and ball valves, you can rig your system to make your tanks connected or isolated as and when required, without losing air as you do so, and do the reconfiguration in minutes.

Talk to your local compressed air valves and cylinders supplier. They will be able to help out with the parts and the design.

Cheers,

Bill

Comments for Plumbing my new 8 HP Honda driven compressor

Click here to add your own comments

Feb 03, 2011
Thanks....
by: Joe Grippi

Thanks Bill, with you help so provided, I will start my air project....Regards......Joe

___________________

You are most welcome. Good luck.

B.

Feb 02, 2011
A quick and imformative reply
by: Joe Grippi

Thank you Bill for your help in this, especially your quick response I appreciate it greatly......My tank stands for the pickup bed wing tanks are ready and waiting, and I am anxious to get to the plumbing....Please may I ask further,with a 1 1/2 inch outlet from the compressor, should I manifold it at the same dimension, then reduce to the 3/4 inch to the air units, or should I carry this large output volume and reduce later in the configuration?.....Please keep in mind, from the compressor unit to the two wing tanks is only a couple feet of bed length, with the other 30 gallon vertical tank about 10 to 12 feet aft of this.....Finally, should I connect with the coupler type that does not reduce the internal hose volume, or am I okay with the usual coupling types?......Surly appreciate your expertise in this......Thanks again.....Joe......

____________________

You can't go wrong using the same dimension for plumbing as the outlet of the compressor discharge.

A 1 1/2" line is huge, and will flow massive amounts of compressed air.

The only way to be sure is is to know, when you are using the compressed air, how much air will your applications need in CFM and Pressure.

The higher those numbers, the larger the lines required.

On the other hand, if the air tool has a 1/2" inlet for air supply, then, in theory, and depending on how far the air has to travel, you should be able to supply that tool with a 1/2" ID air line, yes?

You can't go wrong going with big lines, except where it costs you more money to no real use.

I would always opt for fittings that have full line internal dimensions to help reduce line loss.

Cheers,

Bill


Click here to add your own comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Plumbing a compressor question.

pressure switch hose

where does the little hose from pressure go?

____________
Bill says...

I would be delighted to try and help you, but I don't know what hose and what pressure you are talking about.

Can you be more specific, and, perhaps, send in a photo so we can help you?

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Plumbing a compressor question.