How do submersible pumps work?

[JohnW2]

That is a matter of pressure created by the pump.

Exactly - and to which there is no theoretical limit. What you said about the theoretical maximum of about 33.5 feet of lift (33.5 feet of water being average atmospheric pressure) applies only to 'lift pumps' (since it's then just atmospheric pressure lifting the water), not to 'force pumps' such as we are discussing.

Kind Regards, John

 

[Harry Bloomfield]

Exactly - and to which there is no theoretical limit. What you said about the theoretical maximum of about 33.5 feet of lift (33.5 feet of water being average atmospheric pressure) applies only to 'lift pumps' (since it's then just atmospheric pressure lifting the water), not to 'force pumps' such as we are discussing.

Correct!

 

[JohnW2]

Correct!

I know I am (I remember a few things from when I was 11)

Kind Regards, John

 

[bernardgreen]

add kinetic energy of a rotating mass of liquid to the equations.

 

[JohnW2]

add kinetic energy of a rotating mass of liquid to the equations.

That energy will presumably only be manifested as something useful if the rotating liquid hits something (like a 'baffle'), won't it?

Simply having a mass of liquid spinning around continuously within a chamber would not, in itself, achieve anything useful in terms of pumping, no matter how much energy was involved in that spinning, would it?

Kind Regards, John

 

[bernardgreen]

hits something (like a 'baffle'), won't it?

or the water in the delivery pipe.......

 

[JohnW2]

or the water in the delivery pipe.......

If it were literally just "a rotating mass of liquid" (which is what you mentioned) that would not interact with the water in the delivery pipe - what would interact with it would be the water 'flung out' tangentially towards the delivery pipe.

However, to talk about the kinetic energy of that tangential flow is just another way of talking about the increased pressure due to that ;flinging out', so I don't think what you are saying differs from what we have all been talking about.

On the subject of that tangential movement of water ... I have repeatedly asserted that my pump has no 'scoop' of any sort, which is literally true. However, one thing that I hadn't previously 'taken in' is that the outlet tube is tangential, not radial, to the pump casing. That will certainly help it to 'capture' the water being 'thrown out' - although not to the extent of having much impact on my 'amazement'! ...

Kind Regards, John

 

[Harry Bloomfield]

However, one thing that I hadn't previously 'taken in' is that the outlet tube is tangential, not radial, to the pump casing. That will certainly help it to 'capture' the water being 'thrown out' - although not to the extent of having much impact on my 'amazement'! ...

There's your scoop

 

[JohnW2]

There's your scoop

Yes, sort-of - which is why I mentioned it when I thought about it.

More generally, I can't help but wonder whether I am alone in being amazed by the fact that what I'm looking at can achieve what it does. Does no-one else feel the same as I do?

Kind Regards, John