using hydraulic hose for air compressor

[big hunter]

So I will go with a hydraulic hose to hook up the air compressor to the hard line. The valve on the compressor is 1/2 inside diameter (without measuring it). The inside of the fittings for a 1/2 inch hydraulic hose are about 5/16 (maybe 3/8 at most) inside diameter. How much will that effect the air flow...air coming out of the valve with 1/2 dia. going into 5/16 fitting, then into a 1/2 hose, then back into a 5/16 fitting, then out into the 1/2 hard pipe.
Am I getting to picky...it won't amount to much, or should I get fitting that have a 1/2 dia. and the hose will be like 3/4. Do ya follow what I'm saying....thanks...sometimes I think too much with my small brain

 

[old]

The amount of air flow that it will cut down on is so small that unless you are running something that takes the max of your compressor you will not even notice it

 

[VaTom]

It's your shop, be picky.

I ran steel pipe to my IR compressor, don't remember if it was 3/4" or 1". It goes to an additional tank, considerably larger than the IR has. Then copper to the whole shop. If you want much air volume, you want larger diameter. I ran 1/2" copper, should have run 3/4".

 

[JMS/.MN]

Isn"t the compressor equipped with a larger outlet? I think my 60 gal is either 3/4 or 1 inch. I use that size hyd hose going to the half-inch air line around the shop.

 

[big hunter]

the valve that is on there from the factory, when you open the valve and watch the ball turn and open...when it is open it looks to be 1/2...the threads on the valve are 3/4 inch outside dia. I don't know what to say.

 

[big hunter]

your the only one so far that understood my question...

 

[big hunter]

your the only one so far that understood my question...

 

[CNKS]

I wouldn't be too concerned about the fittings, the fittings for the air tools are only about 1/4 inch. But, if it was mine I would run 3/4 inch pipe, with 1/2 inch drops. Copper is nice, but I used black pipe run through a GOOD water filter. For painting, the drop has a second filter. There is 0 water in either filter, the second is just insurance. Distance to first filter is about 70 feet. No tools including a sandblaster get water in them. In addition,there is less pressure drop with 3/4 opposed to 1/2. I have about a 100' run.

 

[old]

LOL. I understand it because #1 years ago I worked with air systems in a big factory I.E. Tracker Marine in Lebanon MO and had to help keep that big air system up and running. #2 I have a compressor in my shop that has a hyd hose set up on it like your wanting to do and it has worked just fine for decades

 

[Gun guru]

Hydraulic hose is measured with the ID, not the OD. Hydraulic steel tubing is measured with the OD and a wall thickness is quoted, for example--1/2 .049 wall thickness with have an inside Diameter of .402". Pipe is measured as a nominal size, 2" pipe has an outside diameter of about 2.375 and an inside diameter of about 2.065, this is schedule 40, schedule 80 will have a smaller ID.

You should buy a piece of 1/2" hose rated for 500-1000 psi working pressure for your compressor and then get 1/2" JIC swivel ends for the hose.

 

[big hunter]

I know hydraulic hose is measured with the inside diameter...what I was saying is...the inside diameter of the fitting that gets crimped onto the end of the hose is smaller than 1/2 inch, it's about 5/16ths in diameter...hence the inside of the fitting is smaller than the 1/2 inch inside dia. valve, 1/2 inch inside dia. hydraulic hose, and the 1/2 copper pipe I'm running in the shop...
I was thinking that the small fittings would chock down the volumn of air....I don't know.

 

[greygoat]

My Quincy compressor outlet is 3/4 pipe. I use
a 3/4 hydraulic hose with 3/4 male pipe ends,
between the compresser and 1/2 black iron pipe
system that goes all around my shop. I put a
bell shape reducer 3/4 female to 1/2 female
on the end of the pipe. The hose gives some flex
between the compressor and the rigid fastened
pipe.

 

[markiz41]

Considering that the max cfm through a 1 square inch cross section is about 140, the max you can get through a 5/16 diameter pipe is around 11 cfm. In my calculations )) You decide, do you need more than that?

 

[Bspauld]

That brings up a question,Why are some pipes measured ID and some OD.Copper tubing is measured noth ways sometimes? Why do they measure any tube that has a flow in it by the OD? The ID is whats importent,just a question I have had for years,

 

[Gun guru]

Tubing is measured on the OD cause a set size, like 1/2" needs to be exactly 1/2" OD for the flaring tool and the fittings that are used for it. The wall size changes in the tubing go up and down for higher or lower pressure ranges in the systems. I dont remember seeing copper tubing measured from the ID, I will have to look that up.
Carbon steel tubing and Stainless tubing will have a table of values that will indicate working pressure and burst pressure with the various wall thicknesses.

 

[Gun guru]

To be safe I would get a 3/4" hose with 3/4" fittings on the end. a 5/16" ID in a hose fitting for a 1/2" hose doesnt sound right to me.

 

[Bspauld]

That makes sense to me,thanks. Back in the 50s I worked at a Food Company,Dr Kellog started the cerial business in Battle Creek, and I had to go to the hardware store a lot,Back then copper tubing had the ID size on it,Thanks again for the reply

 

[Joe(TX)]

A 1/2 air hose reduces down at the ends also if you look. The reduced diameter for a short distance will have no noticable effect. Pressure drop is associated with high flow (high velocity) only.

 

[MarkB_MI]

Pressure drop is proportional to the length of the pipe (or hose) and inversely proportional to the cross-sectional area of the pipe. In other words a short restriction will have little effect on the airflow.

Let's say you have 40 feet of half-inch ID pipe and five feet of 3/8 inch ID hose. The half inch pipe has a cross-sectional area of .25 square inches, the area of the 3/8 inch hose is .14 sq. in. The ratio of pressure drop across the two segments is:

(40 x .25) : (5 x .14)
or 10:0.7
or 14:1

Yes, you get fourteen times the pressure drop over the larger pipe than over the smaller but shorter hose. And you're probably going to hook a 3/8" hose from the pipe outlet to your air tool, so the pressure drop across the compressor-to-pipe hose will be insignificant. And the slight restriction from the various pipe and hose fittings won't amount to much unless they severely restrict the flow. Even 1/4 inch ID fittings shouldn't be a problem as long as there aren't too many of them.