View Full Version : Air Pressure Question??

10-06-2008, 12:43 PM
I am working on an Air Line system for a shop along with a Nitrogen Generator. NOW the main lines I made 1.250 (1 1/4) inch dia. BUT I noticed that the air dryer has 3/4 inch ports in and out. Now my question is after having bought a pile of 1.250 diameter black pipe is can i just reduce the line to 3/4 into and out the dryer? ?? and then go up to 1.250 again? Or doesnt it matter? Thanx Guys Mike

10-06-2008, 01:59 PM
You will likely get a small pressure drop from reducing to 3/4 and going back up. It shouldn't affect much however as it should be a lot smaller than the drop from running the whole thing on a very long 3/4 inch pipe instead.

Beyond this simple statement, some calculations would likely be necessary to determine if there is a better way. Likely not worth bothering with unless it doesn't work satisfactorily or is too noisy.

10-06-2008, 03:18 PM
I may be wrong but I think that you will see a slight difference in air volume/delivery instead of a drop in pressure as you are restricting the flow. Like I said, I may be wrong about this as it is a thing that is sometimes hard to visualize.

10-06-2008, 03:25 PM
You will see a little more pressure drop at maximum delivery than you would if the dryer had full sized fittings. But, you can still push a lot of air through a 3/4" fitting.