Sciencey odd question just occured in my daily musings...

[TGor]

Lot's of smoke and mirrors on this one guys. I wonder when they stopped teaching the Hydraulic Gradient phenomenon to plumbers?? ; anyhow our plumbing teacher used to have a rig with 1/4" dia horizontal pipe about 2 metres long with a tap on one end. There were vertical branches (open ended) from the pipe at about 200mm intervals in glass pipe about 400mm high. and the end branch away from the tap end had a bit of a reservoir which was filled with coloured water, firstly with the tap closed so that the whole rig was filled and you could see coloured water at equal heights in each vertical branch. When the tap was opened and the water flowed the level in each branch dropped but not equally so that you could actually run a line through from the resevoir to the tap. This was to demonstrate the difference between Static Pressure and Hydraulic pressure .. that is when water flows through a pipe it loses pressure due to friction against the pipe wall.So in this way you would be able to easily find out if the original question is true by setting up a bigger scale rig (but still with 1/4") and experiment with the reservoir height and length of pipe till nothing comes out. Good luck

 

[fuzzy]

that sounds interesting any chance of a skethc or link to it happening on you tube or something?

 

[fuzzy]

Up hill, down or on the level? I'd be gettn' the meter gov checked if I was getting that sort of presure ... imagine the cooker flame!!! lol

imagine how quick youd cook a pizza

 

[WaterTight]

For me, personally, it turns out I had a big enough brain to think up the question but far too small a brain to understand half the answers. But since ignorance is evidently bliss I'm not complaining.

 

[Mrs Tara Plumbi]

I couldn’t let the challenge of this question leave my head
I think the friction is irrelevant and I think the amount of water in the pipe needs to be big enough to be exerting and equal and opposite force to the mains pressure
I may have the answer found in a plumbing book as to when the 3 bar of mains pressure runs out, I could be very wrong.
Please check my maths I may have made massive mistakes.

Townsend Plumbing 1 second edition 1969

Pages 51-3 chapter about water.

If we assume water pressure of 3 bar = 30 m head
And 15mm pipework

Intensity of pressure = head x 9.8 kilo Newton kN/m2
= 294 kN/m2
Total pressure = intensity of pressure x area
Total pressure = 294 kN/m2 x (3.142 x 7.52) m2= 51,961 kN

1 tonne of force = 1000 kg f = 9800 newtons = 1m3 of water

Therefore:
51,961 / 9.8 = 5,302 tonnes = 53,020m3 or 53 million litres of water

I think this means that 3 bar mains water pressure is enough to move 5,302 tonnes of water through a 15mm pipe

A litre is 1cm3 of water and if this pipe hold 0.15 litres per metre then 150 litre per km

At this point I have lost interest and Big Bang has come on TV … come on I’m nearly there.

353,467 kilometres of pipe filled with water.
By the way, circumference of the earth is a little over 40,000. so to all practical terestrial purposes the water will never stop coming.

 

[villa_tom]

I couldn’t let the challenge of this question leave my head
I think the friction is irrelevant and I think the amount of water in the pipe needs to be big enough to be exerting and equal and opposite force to the mains pressure
I may have the answer found in a plumbing book as to when the 3 bar of mains pressure runs out, I could be very wrong.
Please check my maths I may have made massive mistakes.

Townsend Plumbing 1 second edition 1969

Pages 51-3 chapter about water.

If we assume water pressure of 3 bar = 30 m head
And 15mm pipework

Intensity of pressure = head x 9.8 kilo Newton kN/m2
= 294 kN/m2
Total pressure = intensity of pressure x area
Total pressure = 294 kN/m2 x (3.142 x 7.52) m2= 51,961 kN

1 tonne of force = 1000 kg f = 9800 newtons = 1m3 of water

Therefore:
51,961 / 9.8 = 5,302 tonnes = 53,020m3 or 53 million litres of water

I think this means that 3 bar mains water pressure is enough to move 5,302 tonnes of water through a 15mm pipe

A litre is 1cm3 of water and if this pipe hold 0.15 litres per metre then 150 litre per km

At this point I have lost interest and Big Bang has come on TV … come on I’m nearly there.

353,467 kilometres of pipe filled with water.
By the way, circumference of the earth is a little over 40,000. so to all practical terestrial purposes the water will never stop coming.

My brain just burst :willy_nilly:

 

[unguided1]

I couldn’t let the challenge of this question leave my head
I think the friction is irrelevant and I think the amount of water in the pipe needs to be big enough to be exerting and equal and opposite force to the mains pressure
I may have the answer found in a plumbing book as to when the 3 bar of mains pressure runs out, I could be very wrong.
Please check my maths I may have made massive mistakes.

Townsend Plumbing 1 second edition 1969

Pages 51-3 chapter about water.

If we assume water pressure of 3 bar = 30 m head
And 15mm pipework

Intensity of pressure = head x 9.8 kilo Newton kN/m2
= 294 kN/m2
Total pressure = intensity of pressure x area
Total pressure = 294 kN/m2 x (3.142 x 7.52) m2= 51,961 kN

1 tonne of force = 1000 kg f = 9800 newtons = 1m3 of water

Therefore:
51,961 / 9.8 = 5,302 tonnes = 53,020m3 or 53 million litres of water

I think this means that 3 bar mains water pressure is enough to move 5,302 tonnes of water through a 15mm pipe

A litre is 1cm3 of water and if this pipe hold 0.15 litres per metre then 150 litre per km

At this point I have lost interest and Big Bang has come on TV … come on I’m nearly there.

353,467 kilometres of pipe filled with water.
By the way, circumference of the earth is a little over 40,000. so to all practical terestrial purposes the water will never stop coming.

Yeah wot evar but is it enough fer the loveslave ter fill the kettle?????

 

[WaterTight]

I couldn’t let the challenge of this question leave my head
I think the friction is irrelevant and I think the amount of water in the pipe needs to be big enough to be exerting and equal and opposite force to the mains pressure
I may have the answer found in a plumbing book as to when the 3 bar of mains pressure runs out, I could be very wrong.
Please check my maths I may have made massive mistakes.

Townsend Plumbing 1 second edition 1969

Pages 51-3 chapter about water.

If we assume water pressure of 3 bar = 30 m head
And 15mm pipework

Intensity of pressure = head x 9.8 kilo Newton kN/m2
= 294 kN/m2
Total pressure = intensity of pressure x area
Total pressure = 294 kN/m2 x (3.142 x 7.52) m2= 51,961 kN

1 tonne of force = 1000 kg f = 9800 newtons = 1m3 of water

Therefore:
51,961 / 9.8 = 5,302 tonnes = 53,020m3 or 53 million litres of water

I think this means that 3 bar mains water pressure is enough to move 5,302 tonnes of water through a 15mm pipe

A litre is 1cm3 of water and if this pipe hold 0.15 litres per metre then 150 litre per km

At this point I have lost interest and Big Bang has come on TV … come on I’m nearly there.

353,467 kilometres of pipe filled with water.
By the way, circumference of the earth is a little over 40,000. so to all practical terestrial purposes the water will never stop coming.

.....Guh?

 

[fuzzy]

see if i got this, if you have 353,467km of 15mm tube, 3 bar is sufficient?

 

[Mrs Tara Plumbi]

see if i got this, if you have 353,467km of 15mm tube, 3 bar is sufficient?

Fuzzy - exactly the opposit
3 bar will not move this amount of water!

As I said:
1. i may have made a mistake with the maths as this seems a really big number, the the principles were right but my sums wrong OR
2. these formulas might be completely the wrong way of working out the answer

And - as when the computer said the answer is 42 then they set off to fing out the question.
the question i think i have tried to answer is if pipe was laid completely flat, no bends, how much standing water would be in the pipe before you could turn on 3 bars of mains pressure but not move anything?

Me thinks this should be addressed to some maths forum or we should just stick with the experiment as discussed.
What are the chances of winning lottery funding to fund the experiement which will prove my answer correct or incorrect?