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UK Window Cleaning Forum => Window Cleaning Forum => Topic started by: pylofm on May 08, 2007, 02:10:22 pm

Title: Fluid dynamics
Post by: pylofm on May 08, 2007, 02:10:22 pm

Ok all you boffins....Why do we bother with 6mm & 8mm id hose, why dont we just use long lenghts of the hose that goes on the pole itself...

Sorry if I am not seeing something very obvious...like I say...just a thought in a tiny mind.. ;D

Cheers
Dave.

Title: Re: Fluid dynamics
Post by: Jeff Brimble on May 08, 2007, 03:00:02 pm

As you have said its down to fluid dynamics or water friction. I happliy use 4mmID/6mmOD silicon hose its light and there is not much back pressure on the pump, But after 25- 30m the flow rate drops below 1 pint/0.6L  You could then go to the bigger hose or a more powerful pump.
I use a bit less than 1/2L per min with a 28cm brush-the brush also has an influence as a 15" would need more water than a 10"

Title: Re: Fluid dynamics
Post by: pylofm on May 08, 2007, 04:54:40 pm

Thanks Jeff...that does explain it...

Cheers
Dave.

Title: Re: Fluid dynamics
Post by: Paul Coleman on May 08, 2007, 06:01:49 pm

Quote from: pylofm on May 08, 2007, 02:10:22 pm

Ok all you boffins....Why do we bother with 6mm & 8mm id hose, why dont we just use long lenghts of the hose that goes on the pole itself...

Sorry if I am not seeing something very obvious...like I say...just a thought in a tiny mind.. ;D

Cheers
Dave.

Apart from what Jeff says about the flow rate, there is also the issue of visibility.  There may be yellow pole hose around but the only types I've seen are either black or clear.  Apart from the pole hose which can be any colour, I prefer my other hoses to be yellow for visibilty and safety.

Title: Re: Fluid dynamics
Post by: Jeff Brimble on May 08, 2007, 06:10:42 pm

What colour is yellow ? said the the colour blind, blindman  ;D

Title: Re: Fluid dynamics
Post by: Paul Coleman on May 08, 2007, 06:24:13 pm

Quote from: Jeff Brimble- The Electric Window Cleaner on May 08, 2007, 06:10:42 pm

What colour is yellow ? said the the colour blind, blindman  ;D

Of course if someone is blind, it can be any colour   :)

Title: Re: Fluid dynamics
Post by: JM123 on May 09, 2007, 01:03:01 am

the pole hose we use is 5mm id - I've tried 50m before and must say I still got a good flow, it was incredibly easy to work with too but the risk it poses as a trip hazard simply isn't worth it - also it will split much more easily than than standard reinforced mini/micro

Title: Re: Fluid dynamics
Post by: JM123 on May 09, 2007, 01:06:27 am

oh yeah - 'fluid dynamics', I spent 7 years studying fluid dynamics (of which fluid dynamics and thermodynamics constitute 33% of)

you've just brought back some terrible memories of trying to calculate dryness fractions etc - horrible horrible stuff.