Thread: Air compressor CFM lost-lenghts of black pipe??.

Tweet

Here is what I am asking.I have a heavy duty I/R compressor on
60 gallon tank.For the sake of this thread lets say it is rated at
the outlet of the compressor 15CFM @ 90 lbs.I want to plumb
in 1/2 black pipe that on one side of the shop would be from 50' to 70'(with outlets quick connectors every 16') and in the middle of that a "T" that go up and over to feed the other side
of the shop and two outlets that might total another 50'.

The question is given the footage of black pipe is there a lost of CFM at the quick connectors??.How is that figured out??.If I have had second 60 gallon tank,would that effect the CFM rating??

I would think the pressure at 50' would be the same at 100' and I would think that the pressure at 50' ft. comming out of the coupler would be the same at 100' ft.
Unless there are leaks in the line or couplers or some one is using a air tool before the far coupler.
With another 60 gallon tank you will get more volume but it will not effect the cfm's unless you have a bigger pump on that tank, then the one you stated above. I would try to talk to one of the painters on here, they will probably be your best person for air compressor set up info.
Kurt

Following along the lines of a second 60 gallon tank,I know of one
listed on craigslist.The space I have,I would place the compressor
and tank at one end of the 50' black pipe and at the other end the second tank.I am thinking I would bring in a inlet on the top of the second tank and then loop the outlet back into the end of the 50' black pipe.I don't know how the dymanics of air works.Would I
need one way valves to the inlet and outlet of the second tank??

Gary as Kurt said the second tank would provide more volume to the system but it would not affect the CFM of the system (it will double the recovery time of the system however).

With good quality disconnects you should not see a CFM loss at connections however it could happen with poor quality ones and I have also seen it happen with cheap air hoses after the coupler.

Ideally you also will want drops (water traps) with drains below each coupler.

There is also some good information in this post.

inexpensive filter/dryer

Gary,
If you're looking at a one or two man shop you won't have any worry with pressure drop in your system as described. Adding a second air tank is going to give you more storage volume (so does your header system), which only delays the start of the compressor as you use air, but then simply takes longer for the compressor to refill which gets your compressor hot. If you're painting your enemy system heat, and a good system is going to have your compressor running less than 50% of the time to keep it from getting too hot and putting more water into your air. You should be fine with 15scfm @ 90psig, especially with a newer gun. I would not think you need a second tank. Check your tools for flow capacity and compare to your compressor flow. On your piping, run your first line up from your tank, and slope the horizontal header back towards your tank, taking drops down from that header to your work stations. An automatic water drain on the tank is nice, but if you open your drain several times a day during heavy use it will work, too.

What everyone has said so far is true. Once you have it plumbed and all the outlets installed just make sure you have a trap and a good water filter before the main outlet. If you do any painting with a spray gun, do not put an inline oiler in. It will introduce fine mists of oil to keep your air tools lubed and when you paint also add oil to the line and mix with the paint.
I always keep air tool oil handy and use a few drops when using an air tool, much easier.
One thing you should keep in mind. ......for every foot of hose you use , it will drop pressure by 2 lbs per 10 ft of hose. So when or if you paint and need to have a specific pressure at the gun, if you have 50ft of hose, you will need to bump up the pressure by 10 more lbs.

Originally Posted by sunsetdart

One thing you should keep in mind. ......for every foot of hose you use , it will drop pressure by 2 lbs per 10 ft of hose. So when or if you paint and need to have a specific pressure at the gun, if you have 50ft of hose, you will need to bump up the pressure by 10 more lbs.

I put in a small regulator with guage at the gun, or on a QC adapter for the hose end if you're running multiple guns. That way you run your main regulator at 90, but can adjust your pressure at the gun to what you want when flowing. Takes the guesswork out, and it was like $10 at the auto paint store.

Thanks all for your input.

For that length of run, I would use 3/4 pipe up to the t and then across the shop--then the 1/2 is OK--at the end of a long run when you trigger a grinder or heavy tool the immediate drod is slow to recover a mile from the compressor--and like has already been said---slope the intial run of pipe so it goes uphill away from compressor and the as the air cools and the moisture condenses it will drain back into the main tank where you can easily drain it off--

Black iron pipe will rust inside with the moisture......you will have to run a filter at every outlet OR you will be blowing rust on everything and stopping up small orifices. Black iron is not the preferred piping for pneumatics. Typically copper or stainless is the best, there are some new plastic systems designed for air (not PVC pipe).

mike in tucson

I ran 3/4" copper from the compressor to each drop. There is a 3/4" line down both sides of the shop with drops every where I also installed 2 presure gauges one at each end of the shop (shop is 74' long) so I can tell just by looking up whats going on. My drops are 3/4" untill they reach the quick connect. There is a drain at the bottom of each drop and the Q/C is to the side. Personaly I wouldn't use black pipe. I can't imagin what you would be running in a shop that would require a constant PSI and CFM Spray equiptment uses regulators at the gun. I have a seperator by the compressor and I drain the tank regularly. As was mentioned Never put oil in the lines or hoses. Always oil the tools before use. But then again thats just my $.02 worth

I've got a 2 stage with an 80 gal tank, then a 60 gallon tank plumbed to it. The compressor does run more to fill both tanks, but it doesn't run near as often. Had it this way for a couple years now and no problems at all. The rest of the system is 1" pipe plumbed to a dryer/separator then a couple of QD's for the air hoses. My garage is small, so the two 50' air hoses cover the whole place. I'm with Charlie and the rest, I don't use an oiler, just keep a bottle of air tool oil handy. The extra tank serves as a very good water trap and air cooler for the system, too! Very seldom that any moisture even makes it to the dryer.

I have an oiler with a dedicated oil line/ hose.. but it doesn't work well, and I have considered replacing the oiler with another drier

Originally Posted by Dave Severson

I've got a 2 stage with an 80 gal tank, then a 60 gallon tank plumbed to it. The compressor does run more to fill both tanks, but it doesn't run near as often. Had it this way for a couple years now and no problems at all. The rest of the system is 1" pipe plumbed to a dryer/separator then a couple of QD's for the air hoses. My garage is small, so the two 50' air hoses cover the whole place. I'm with Charlie and the rest, I don't use an oiler, just keep a bottle of air tool oil handy. The extra tank serves as a very good water trap and air cooler for the system, too! Very seldom that any moisture even makes it to the dryer.

What Dave says is very true, but his system works because the compressor capacity is more than his use rate. If a guy tries to use a small compressor by adding tanks for added capacity the compressor is still going to run for extended periods once it starts, unless the air demand goes away. There are lots of ways to put a system together, but there's not much way to make a compressor that's too small work right.
On the pipe material, I considered black pipe and had concerns with rust, but by the time I considered the fittings, weight being hung, threading joints, etc to copper the choice for me was hard copper tubing with solder joints like Charlie & Robot mentioned. It's easy to work with, light to hang, and lasts forever.

I plumbed my shop with 1" galvanized pipe. Off of the compressor I have two 1"inline filters and at each drop I have a 1/2" regulator that is off of a tee with a blowdown valve at each also. You do not want to run black pipe as it will corrode inside. Either galvanized or copper or stainless is your best bet. Do not run your header in 1/2" run it in 3/4" or 1" and then do your drops in 1/2". Don't forget to remove that crappy draincock in the bottom of the tank and pipe it out with a proper valve so it is easy to drain your tank after use. This will definately extend the lfe of your system. This is exactly how we install instrument air systems in plants worlwide so I know it works. Oh and yes your CFM will be affected by that 1/2" pipe to some degree at the user.