It's like putting a straw in a glass of water and with your thumb on top can pull it out with water intact.  The pressure inside is less than outside.  The weight (pressure) of the water only becomes a factor when the "straw" is 8m or more.

Well the water did disappear somewhere or I wouldn't have pulled it all to bits.
When the pump wouldn't prime I put the hose into the filler cap on top of the pump. I could go on filling but the reservoir would not fill up. If I then jiggled the pipes into the bore up and down (I think making a wave to get any rubbish out of the footer valve), I could then fill the reservoir and pipes and the pump would work.

Also why do you have a footer valve if you don't need it to help prime the pump?











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10 minutes ago, carlyai said:

Well the water did disappear somewhere or I wouldn't have pulled it all to bits.
When the pump wouldn't prime I put the hose into the filler cap on top of the pump. I could go on filling but the reservoir would not fill up. If I then jiggled the pipes into the bore up and down (I think making a wave to get any rubbish out of the footer valve), I could then fill the reservoir and pipes and the pump would work.

Also why do you have a footer valve if you don't need it to help prime the pump?
 

I don't know why you have this problem (it seems like the prime reservoir should not be draining through the pump) so maybe your pump is not quite right.  (?)  My pump can be primed by simply allowing the mains to come in through the output pipe (the mains is shut off when the pump is running) although it maintains prime when the pump is off.  The foot valve should only come into play when the jet pump is running.

I don't know why you have this problem (it seems like the prime reservoir should not be draining through the pump) so maybe your pump is not quite right.  (?)  My pump can be primed by simply allowing the mains to come in through the output pipe (the mains is shut off when the pump is running) although it maintains prime when the pump is off.  The foot valve should only come into play when the jet pump is running.

I think I'm using the wrong term. There are two filler caps. One that fills up the suction and pressure pipes is the one that would lose the water.

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On ‎22‎/‎04‎/‎2018 at 8:53 AM, Naam said:

i beg to differ Crossy. many rainy seasons ago i took a submersible pump to Nigeria. as i was flying on a 747 this pump become undoubtedly a jet pump.

 

Carlyai mentioned that the venturi is smaller than a G-spot. perhaps this fact overcame the laws of physics?

 

Naam:

Not to be outdone, many many moons/ rainy sessions, years ago, I airfreighted a 400ft long, 6" column, line shaft vertical axial flow pump disassembled into manageable lengths, complete with right angled gearbox drive and Caterpillar diesel engine to Mogadishu Somalia for an emergency aid project. So - does that now become a hybrid axial flow jet pump as well?   Unfortunately the project failed as the bore-hole wasn't vertical it had something like a 3ft deviation over  its length.

I think I'm using the wrong term. There are two filler caps. One that fills up the suction and pressure pipes is the one that would lose the water.

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What about this:

P = ρ g h is the formula for water pressure.

If we say g and p are constants, then Water Pressure varies proportional to height. So the pressure at the bottom of my 7m pipe would be more than the 2 m from the water table to the bottom of pipe.

Wrong again?



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Naam:
Not to be outdone, many many moons/ rainy sessions, years ago, I airfreighted a 400ft long, 6" column, line shaft vertical axial flow pump disassembled into manageable lengths, complete with right angled gearbox drive and Caterpillar diesel engine to Mogadishu Somalia for an emergency aid project. So - does that now become a hybrid axial flow jet pump as well?   Unfortunately the project failed as the bore-hole wasn't vertical it had something like a 3ft deviation over  its length.

Nice one Naam. Fun place to work?

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4 minutes ago, carlyai said:

What about this:

P = ρ g h is the formula for water pressure.

If we say g and p are constants, then Water Pressure varies proportional to height. So the pressure at the bottom of my 7m pipe would be more than the 2 m from the water table to the bottom of pipe.

Wrong again?



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The water pressure on the NRV at the bottom of you inlet pipe is equal to the water level above the water table. 

5 hours ago, carlyai said:

What about this:

P = ρ g h is the formula for water pressure.

If we say g and p are constants, then Water Pressure varies proportional to height. So the pressure at the bottom of my 7m pipe would be more than the 2 m from the water table to the bottom of pipe.

Wrong again?



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Rule of thumb, 10m head is equivalent to 1 bar

7 hours ago, Artisi said:

Naam:

Not to be outdone, many many moons/ rainy sessions, years ago, I airfreighted a 400ft long, 6" column, line shaft vertical axial flow pump disassembled into manageable lengths, complete with right angled gearbox drive and Caterpillar diesel engine to Mogadishu Somalia for an emergency aid project. So - does that now become a hybrid axial flow jet pump as well?   Unfortunately the project failed as the bore-hole wasn't vertical it had something like a 3ft deviation over  its length.

yes it does except if the freight was done by a turbo-prop. 

Rule of thumb, 10m head is equivalent to 1 bar

Hi, so a pipe with 10 m of water in it has 1 bar of pressure at the bottom exerted downward?
A pipe with 2 m of water under it has 2/10 of a bar of pressure exerted upwards?
So if the pipe has no NRV the water in the pipe will escape?

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yes it does except if the freight was done by a turbo-prop.  [emoji2]

How come the spell checker won't let you write 'b* o *ll* o*c*k *s *e*d any more? It's a good word colonists use for for expressive purposes.

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1 hour ago, carlyai said:

Hi, so a pipe with 10 m of water in it has 1 bar of pressure at the bottom exerted downward?

How dare you call me hi so.

1 hour ago, carlyai said:

A pipe with 2 m of water under it has 2/10 of a bar of pressure exerted upwards?

Downwards, something to do with gravity I think

1 hour ago, carlyai said:

So if the pipe has no NRV the water in the pipe will escape?

 

 

 

 

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No foot valve, or one stuck open, if you have cracked fittings at the top to let air in, yep.

No foot valve, or one stuck open, if you have cracked fittings at the top to let air in, yep.

But but, they don't design pump closed systems that have cracked fittings. So why do they include a NRV if you don't need one?

Pressure in a pipe will have lateral pressure as well, won't it, not just downward pressure from gravity.

Just say there is no NRV. The pressure in the 10m pipe, acting downwards is 1 bar.
The water around the pipe in the well is say only 2 m. There must be an equal and opposite force acting upwards on the water in the pipe or it will flow to the lower pressure. Won't it?

I expect Hi So answers.

I think you're trying to tell me that with a perfect system and no NRV the water won't flow out of the pipe. Sounds like magic to me.

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It doesn't always pay to bunk off ... in later life you never know when attending that class would have been useful ... now matrices I might just as well have bunked off ... never used them in nearly sixty years

2 hours ago, Naam said:

yes it does except if the freight was done by a turbo-prop. 

Guess it would have been 707.

GOT IT. [emoji2]

You guys make lousy teachers....for the challenged among us.

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It doesn't always pay to bunk off ... in later life you never know when attending that class would have been useful ... now matrices I might just as well have bunked off ... never used them in nearly sixty years [emoji2]

Right in 1.

When I should have been in the horrible/boring physics and chemical classes I wasn't.
The high school I went too had a housing estate full of tin igloo where they put all the £20 Poms that tried to colonize us again.
The school was full of these Teddy Boys, with their 3/4 length coats and long sideburns and a knife in the back pocket.

Horrible really, so best to wag it.

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7 minutes ago, carlyai said:

The high school I went too had a housing estate full of tin igloo where they put all the £20 Poms that tried to colonize us again.

I thought it was a tenner https://en.wikipedia.org/wiki/Ten_Pound_Poms

 

9 hours ago, carlyai said:

But but, they don't design pump closed systems that have cracked fittings

True, but didn't you say earlier that a couple of your plastic screwed connections were broken, being over-tightened?

12 hours ago, carlyai said:

How come the spell checker won't let you write 'b* o *ll* o*c*k *s *e*d any more? It's a good word colonists use for for expressive purposes.

what spellchecker refuses bóllocks?

3 hours ago, Crossy said:

I thought it was a tenner https://en.wikipedia.org/wiki/Ten_Pound_Poms

 

Reminded me of this (no offence intended!)

 

 

True, but didn't you say earlier that a couple of your plastic screwed connections were broken, being over-tightened?

keep up hi so...that's ages ago..you need a rest from the chicken shed building.

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6 hours ago, carlyai said:

keep up hi so...that's ages ago..you need a rest from the chicken shed building.

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I can't believe this has gone on for 8 pages, Dan Cheeseman will be made up.

 

I forgot now, what was your original query and what has the topic morphed into now.

 

You're right, I'm up to 120 blocks a day and knackered so can't be arsed re-reading from the beginning.

 

<deleted>.

 

Ah, I see Naam used an 'o' with an accent - that's cheating.

48 minutes ago, grollies said:

Ah, I see Naam used an 'o' with an accent - that's cheating.

vhy vöuld outshmarting zome softvare be jeating?

9 hours ago, dinga said:

Reminded me of this (no offence intended!)

 

 

Be careful, I was sin-bined a while back by a particular moderator for calling a WP a WP. 

2 minutes ago, Artisi said:

Be careful, I was sin-bined a while back by a particular moderator for calling a WP a WP. 

Work Permit???

24 minutes ago, Crossy said:

Work Permit???

Whinging Pom ?

I can't believe this has gone on for 8 pages, Dan Cheeseman will be made up.
 
I forgot now, what was your original query and what has the topic morphed into now.
 
You're right, I'm up to 120 blocks a day and knackered so can't be arsed re-reading from the beginning.
 
.
 
Ah, I see Naam used an 'o' with an accent - that's cheating.

Cunning I'd say.

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Thank goodness for Bernoulli's principle, now I understand everything...g spot, WP, accent marks, how straws work, exactly what 1 bar is, and why the Pattaya water is not seamen stained.

 

So it's all up and running, too well in fact, at about 30 l/min. I've throttled the discharge side out of the pump back a bit.

 

Thanks everyone, been fun.

 

 

 

 

 

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