Hose length / pressure loss help please!

[Jackimus]

Hi all,

I've been tying myself up in knots trying to do the maths and AI isn't helping so I'd appreciate a sanity check -

Is a 50m length of 10mm inner diameter air hose feasible?

What sort of pressure loss would you get along that length? Should I increase the inner diameter of the hose?

If the tool wants 90PSI, can I just increase the pressure at the source? E.g. if you would lose 30PSI along that length, set the regulator to 120PSI so it's 90PSI at the other end? (Oversimplifying I'm sure)

Thank you!

 

[Trevorleach]

Pressure loss zero, air flow at 50m will be compromised running hungry air tools.

 

[Dapph2]

There will also be flexing in the hose wall so in effect you inflate and deflate causing a variable pressure to be sensed ,the longer the hose the more noticeable it will be .
Is your hose a simple plastic .or rubber one or is it steel reinforced pressure washer/hydraulic reinforced hose .

 

[Kayos]

There is tables of pressure loss for given diameter and length

 

[Jackimus]

PVC/nitrile blend hose with 'triple polyester yarn reinforcement' is what I was looking at.

90PSI at source, 50m of hose with 10mm inner diameter, 9.4cfm FAD (14cfm x 0.66), is giving me a pressure loss of ~7.5PSI. Sound right?

 

[Munkul]

If the tool wants 90PSI, can I just increase the pressure at the source? E.g. if you would lose 30PSI along that length, set the regulator to 120PSI so it's 90PSI at the other end? (Oversimplifying I'm sure)

No. As soon as you stop the tool, the pipe will increase in pressure up to regulator level then it will surge when you start it again.

It's flowrate that causes the pressure drop. If you know your flowrate then chatgpt will tell you the pressure drop.

 

[Jelly_Sheffield]

Calculating pressure drop in compressible fluid flow is *complicated*, it's a function of:
- pipe diameter,
- pipe length,
- pressure,
- temperature,
- volumetric flow rate, and
- how restrictive any pipe fittings are (which is down to their shape, and isn't always obvious).

If you must... then google "Crane TP410" (TP410M if you prefer metric units) it's well over 100 A4 pages, but lays out all the mathematics clearly and has lookup tables/graphs for most of the core data you will need, very handy reference.


As long as you're not doing anything too weird using tables like @Kayos mentioned to get a decent approximation is usually a good enough approach for workshop/job-site use and much faster


However, in a workshop setting I tend to go for an empirical approach:
- plug the tool I want to use into the length of hose I want to use,
- stand next to the regulator feeding that hose,
- run the tool flat out and look at what the pressure actually is,
- adjust the regulator until the pressure with the tool running is at the desired value.

 

[Jelly_Sheffield]

It's flowrate that causes the pressure drop. If you know your flowrate then chatgpt will tell you the pressure drop.

LLM's are notoriously not good at mathematical computations... Although if you must, Gemini Pro is much less prone to maths errors than GPT.

Also an old fashioned Google search finds plenty of deterministic, guaranteed to be accurate calculators for different types of pressure drop and fluid flow problems if you gather the data to plug in to them...

 

[8ob]

Is a 50m length of 10mm inner diameter air hose feasible?

What sort of pressure loss would you get along that length? Should I increase the inner diameter of the hose?

If the tool wants 90PSI, can I just increase the pressure at the source? E.g. if you would lose 30PSI along that length, set the regulator to 120PSI so it's 90PSI at the other end? (Oversimplifying I'm sure)

Thank you!

50mts is a long way for an air line, the longer 1/2" hoses make my 1" drive nut gun drop off. I would use what you have and add a receiver to the end of the line, keep that all high pressure and regulate down from that point .

Bob

 

[Jackimus]

However, in a workshop setting I tend to go for an empirical approach:
- plug the tool I want to use into the length of hose I want to use,
- stand next to the regulator feeding that hose,
- run the tool flat out and look at what the pressure actually is,
- adjust the regulator until the pressure with the tool running is at the desired value.

Yes, I think you have the right idea - I would rather just check the gauge + tweak until happy, but I hoped to figure out what would be suitable before purchasing.

LLM's are notoriously not good at mathematical computations... Although if you must, Gemini Pro is much less prone to maths errors than GPT.

Exactly the issue I was having, absurdly wrong numbers which made me not trust the more reasonable ones either.

Flow rate = the air consumption of the tool? If so:

Have I got it now?

 

[Munkul]

LLM's are notoriously not good at mathematical computations... Although if you must, Gemini Pro is much less prone to maths errors than GPT.

Also an old fashioned Google search finds plenty of deterministic, guaranteed to be accurate calculators for different types of pressure drop and fluid flow problems if you gather the data to plug in to them...

Its grand for me. And I'm used to doing pressure/flow calcs.

 

[brightspark]

minimum i use is 15mm bore at about 15 meters and drop to 10mm on another 10 m added .longer than that i have a 3/4 bore hose 10 meters long and use c couplings

 

[Pete.]

If the tool wants 90PSI, can I just increase the pressure at the source? E.g. if you would lose 30PSI along that length, set the regulator to 120PSI so it's 90PSI at the other end? (Oversimplifying I'm sure)

Thank you!

Nope you can't do that. You get diminishing returns and generate a lot of heat as well.

Go up in size and you get great gains though. 15mm bore hose flows more than double of 10mm hose (176mm2 area as opposed to 78mm2)

 

[knighty]

what kind of tool do you have at the end of it?

tyre inflator? no problem at all

sand blaster? no chance

 

[premmington]

Last time I refitted the workshop air system - I went for reels of 16mm nylon pneumatic tube. This got an inside diameter of 12mm

I did thou pipe it up as a "ring main" - this really does make a difference. All fittings and valves/regulators were 1/2" (which gives a bore to match the tubing).

Real big air guns 3/4" & 1" - I use off an filter/oiler direct off the tank with an 1/2" ID hose with PCL 100 series fittings.

 

[Jackimus]

what kind of tool do you have at the end of it?

tyre inflator? no problem at all

sand blaster? no chance

In this particular instance, a Tornador cleaning tool which wants 270 litres/minute at minimum 4.5bar? As in, it apparently works fully from 4.5bar up, but doesn't specify an actual pressure it wants. Shrug.

Inflator would be another but as you say, no concern for that.

 

[Jelly_Sheffield]

Yes, I think you have the right idea - I would rather just check the gauge + tweak until happy, but I hoped to figure out what would be suitable before purchasing.

If you're buying long hoses, the answer will always be "as big as you can practically deal with".

I have a 10m length and two 20m lengths of ¾ ID hose with Q-Claw fittings on to extend my air out into the yard.

They can be used standalone for the ¾" impact, big 8" and 9" grinders, or the grit blaster.

Or connected to a manifold with a regulator and several PCL connections on it, to extend 'normal" air tools.

Exactly the issue I was having, absurdly wrong numbers which made me not trust the more reasonable ones either.

Flow rate = the air consumption of the tool? If so:

View attachment 524919

Have I got it now?

It passes the sense-check, and looks very much like you used a calculator on a well regarded resource website.

Its grand for me. And I'm used to doing pressure/flow calcs.

My issue with LLM's is that they can be extremely inconsistent between users, owing to both the random seed used to generate a response, and how very sensitive they are to the exact wording of the prompt...

You, being familiar with the subject are much more likely to give a prompt that makes it work correctly.

Nope you can't do that. You get diminishing returns and generate a lot of heat as well.

Go up in size and you get great gains though. 15mm bore hose flows more than double of 10mm hose (176mm2 area as opposed to 78mm2)

Increasing the static pressure works up to a point... But becomes both less effective and more problematic as a solution the higher the flow rate demanded.

Fully agree it's better to increase hose size if at all possible.

 

[knighty]

~9.5cfm is quite a bit, I wasn't sure if you were posting what you needed in the earlier post or what your compressor can do

50m is a long length to coil in/out when you need it / when you're putting it away

I'd get some shorter ones and add pcl quick release fittings to them, if you get the xf fittings they're higher flow rate

I'd probably buy 3 of these (45m if you could make do?)

Pardon our interruption...

fittings

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note: I didn't spend ages looking for links, there might be better/cheaper things out there... those are just what I would buy

 

[knighty]

p.s. do you have the cleaning tool already? can you test it on your compressor and turn the valve on the compressor up/down to see how much difference it makes?

there's a chance lower flow (to a point) makes naff all difference

 

[MetalMonkey]

What I do is have some longer larger bore hoses and some shorter 3/8" ones which I just use on the end of the tool or for the last few meters, all with XF fittings.
That way you still have something fairly manoeuvrable but you are minimising the length of hose restriction.