Air Hose

[ebscreen]

So we'll be cutting in the second press this weekend, and I had a few questions about air hose.

Gonna do black iron for the wall/ceiling run, and the heavy rubber stuff for the drops and connection to chiller.

My questions is regarding the connections between the compressor (screw) and storage tanks. Right
now I'm only using the standard 1/2" air hose with quick disconnects. My (armchair physicist) assumption
is that the throttle only matters AFTER the tanks, that the tanks are used to build and hold the volume of air, and as long
as the compressor can keep them at pressure the flow only matters after the tanks. I could be wrong though.

My reason for the small line and quick disconnects is in case of primary compressor failure we can switch over to the
small compressors (being used as tanks) easily.

Help Mr. Wizard!!

[inkman996]

I would check the ratings of the hose and connects between the tank and compressor, I believe no matter what the compressor is going to out put at its max pressure till the tank is filled but if your hosing and connects are not rated high enough for that pressure it may blow. Me personally I would just use heavy duty hose with a coupling in the middle for quick changeover.

[Binkspot]

The larger the better less restriction and heat, I would use at least 3/4". You should also have a check valve between the compressor and tanks, it should be located at the tank so it the hose does rupture you wont dump all the air. A steel braided hose instead of the rubber and QD. The hose will start to degrade over time from the heat and oils from the compressor.

Instead of disconnecting the compressor if you had a failure you would be better off installing a valve and QD in one of the tanks to connect the back up compressor to.

[ScreenFoo]

I'm with Binkspot--3/4" BIP for one press here. (with room to grow)   

Putting a valve in front of every QD is also great advice, IMHO.  I have valves in front of every QD branch, but the main line from the chiller to press is all NPT threaded connections.

[ebscreen]

Guess I didn't explain my question very well. My main concern is flow. Pressure is not a problem. Everything past the
tanks will be 1", it's before and between the tanks that I'm wondering if flow/diameter is a concern.

[Zelko-4-EVA]

i hate black iron for air lines - if your chiller dosent work correctly the inside of the black iron will rust and flake into your air filters on the press.  the only air line i use for the distribution is copper.   we use 1" copper from the air compressor to the wet tank, and then to the filters, chiller and then to the other tanks.  the only rubber air lines are the drops to the press - they have the same ID as the copper.

if you use more air than the 1/2" pipe can send from the compressor, wont it starve the presses? 

our 25hp screw compressor has a 1" outlet, it feeds over 300 gallons of storage at 110psi

what is the CFM rating of the air compressor and the size of your air storage tanks?

[Binkspot]

What size is the outlet of the compressor? Go as big as you can with adding as few reducers or bushings as possible unless its a long run. Its ok to step up a size, you just don't want to step back down at the tank, think of it as a funnel. You want the least amount of restriction as possible. The volume of air will be affected by the smaller hose. Most likely the compressor is 3/4" and the receiver has a 2" inlet depending on the setup. In that case step up to at least 1".  1"x 3/4" bell at the compressor and a 2"x1" bushing at the tank.

Take a garden hose without a nozzle and fill a bucket with water, see how long it takes. Then do the same thing again while standing on the hose or kinking it essentially reducing the flow. It will take longer to fill the bucket with the restricted flow. The same applies for compressed air.


 

[ebscreen]

10hp at roughly 25CFM (have to look it up) 150 gallons of storage.

I understand the flow issue, I just wonder if the "source" is really the compressor or the storage tanks.

In my mind, you should never be working off of air direct from the compressor, but always the storage.

In your filling a bucket analogy, you take the original hose with kink (or smaller diameter hose) and fill up a
first bucket (storage tank). You then take a full size no kink hose from that bucket and fill up a second bucket.
As long as the source can keep the first bucket filled (the 2 presses won't take more than 20CFM full bore)
you won't have flow problems.

More of an exercise in physics than anything, these types of things interest me. It'd be trivial to pipe 1" all
the way from compressor to press.

Good to know about the black iron though, I'll look into copper.

[Zelko-4-EVA]

if you had a 1/2" hose filling a bucket, and a 1" hole coming out of the bucket, wont it empty before it can fill?

some people like black iron, its cheaper.  good air filters are necessary. 

i like the fact that i can identify the different gas lines and air lines by sight.  gas only uses black iron, air only uses copper - but thats in my shop.

[mk162]

a filter solves that problem.  iron pipe would be cheaper right now I am pretty sure.  copper costs are outrageous. 

[ebscreen]

Not if the end of the 1" hose (presses) draw less than the the compressor puts out.
IE the compressor would be filling the first bucket faster than the second bucket empties.

Good point about identifying the lines. These won't be run anywhere near eachother but
I'm a visual person as well, and mixing up those two could really ruin your day.

[Binkspot]

If you don't mind the compressor running all the time under load sure you could run directly off a screw compressor. We used to do construction and salvage work using 500 cfm compressors with no tanks 24/7 for months on end.

The copper is great but can be cost prohibitive. It may also need solder joints instead of threaded, makes the job go faster but if you don't know how to solder it could be a disaster.

A 1" trunk or main line then have your drops 3/4 or 1/2 is not a bad idea.

No mater what you use there should be a good general purpose filter before the chiller and each press, I prefer one with a changeable or cleanable element and drain. There should also be a condensation trap made with pipe before the press with a drain.   

Just my $0.02

[mk162]

if you are concerned about identifying the lines they make this magical stuff called paint.

or you can wrap it in warning tape or sign vinyl.  Same thing electricians do when they run wires of the same color.  Mark the visible points with tape to identify the runs through the conduit.

[ebscreen]

Thanks for the suggestions fellas. Again, more of an exercise than anything.

Filter in place, trap is planned.

Copper probably 5x cost of iron. I can solder just about anything, but I don't wanna.

[mk162]

Yeah, I couldn't find L type copper pipe in 1", but M type was $43 per 10ft.  I can only imagine what L or K would be.  Grainger has L for about $70 per 10ft.  I wouldn't trust M for warehouse use...and actually I don't think it is allowed to be used commercially either.  That's residential use only.