Air Hose Diameter - Is Bigger Better?

This matter has already come up in one discussion on pipe diameter. Difficult to search out. hence let me tell the gist.
Smaller diameter = more pressure loss.
If The head generated at the inlet is constant this will result in less flow through pipe (case in case one compressor is feeding multiple connections as is usual case)
If the compressor is feeding only one hose, then the compressor pressure will rise up to take care of line losses and based on the P=Q characteristics curve of the compressor the flow will be gained at the aoutel of the hose.

larger hose will have less pressure drop across it and hence gains in advantage (in almost all cases, except when there may be effect due to large mismatch at the hose - compressor diameters but will be insignificant (relatively) especially with large hose length.

For generating the ppressure at the outlet, put a nozzle with lower diameter. Now due to flow restriction the velocity rises up at the point of application.

Let us say the pressure drop on hose is P_l (large dia) and P_s (small dia)

obviously P_s > P_L

If the input pressure

P_i = P_s or = P_L+P_n (Pn = nozzle drop)

In the first case, the pressure at outlet of hose is the atm pressure and the velocity at outlet is the inlet velocity.

In second case, pressure at outlet of the hose = (P_i-P_L) and the velocity is much larger (can be calculated by the nozzle calculation)

I am not sure the coherence of the explanation. But the gist is as above.

So your team member is correct. And you can try out too) - provided both the hoses are similar, don't take a corrugated larger hose and a smooth smaller one..

In these cases think the extremes.

Let us atke a 6mm tube and try to descale a pipe.

Then take a 2" hose, put a nozzle and try to descale.

Even better - take the firsr pipe and try to water a plant.

Take second pipe, put the finger at the outlet to choke it (nozzle) and see the spread of the stream.

There are 2 separate issues here.
And it depends what you mean by 'better'
If you want maximum flow then the bigger the diameter the better.
If you want maximum velocity then the design of the orifice and the pressure are the consideration.
Maximum flow and maximum velocity are not the same thing, think of putting your thumb on the outlet of a hose pipe, you restrict the flow but get a higher velocity jet of water with which to soak you colleagues.
Del

good one del. easy to understand the basic difference.the cat is purrrr...ing.

You have been given good advice and explanations of the effects of the larger vs. the smaller diameter hose. I would add only that the larger hose will give you a better capacity for "keeping up" with the work you are doing. As was stated before, the larger hose will have less friction losses than the smaller one. This will allow your compressor to keep more flow coming if you are using the air continuously. Also, the length of the hoses is a copnsideration. The longer the hose, the more friction loss you will create. The larger hose will, again, be less restrictive.

Air exiting to atmospheric pressure is normally limited to sonic velocity above 15 psig. The mass flow is determined by pressure and temperature and the cross section area of the hose or pipe. The discharge velocity is the speed of sound in any event. The size of the hose will affect internal pressure drop. Larger hoses produce less pressure drop. Nozzles may increase discharge coefficient and help focus the flow. Coanda effect nozzles (Exaire) can entrain ambient air to add mass flow.

1. Use big hose to transport air with little pressure drop.
2. Use Nozzles to increase "tip force" focus.
3. Increase supply pressure to increase thrust "mass flow".
4. Use Coanda effect nozzles to increase tip force, mass flow.
5. If you get higher exit velocity from a small hose you will be famous.

Tom

The larger size will give you more head pressure longer but can allow your air tools to over heat with uses if not oil and maintained properly.

Overspeed would be a big concern.