Author Topic: Stuart No1 centrifugal pump  (Read 2760 times)

Offline crueby

  • Full Member
  • *****
  • Posts: 14477
  • Rochester NY
Re: Stuart No1 centrifugal pump
« Reply #30 on: December 08, 2021, 04:34:26 PM »
That gearbox made a huge difference!  What ratio is it?

Offline Steamingandy

  • Full Member
  • ****
  • Posts: 40
Re: Stuart No1 centrifugal pump
« Reply #31 on: December 09, 2021, 12:02:25 AM »
That gearbox made a huge difference!  What ratio is it?
The ratio is 3.5-1 I thought a bit high but seems to be ok

Offline Jasonb

  • Full Member
  • *****
  • Posts: 8467
  • Surrey, UK
Re: Stuart No1 centrifugal pump
« Reply #32 on: December 09, 2021, 07:16:27 AM »
It certainly does increase the flow of the display setup but bear in mind that if you actually want the pump to do real work eg lift water to a head or against a restriction then it will have an adverse effect as the engine has less mechanical advantage.

Online Charles Lamont

  • Full Member
  • ****
  • Posts: 138
Re: Stuart No1 centrifugal pump
« Reply #33 on: December 09, 2021, 05:36:15 PM »
It certainly does increase the flow of the display setup but bear in mind that if you actually want the pump to do real work eg lift water to a head or against a restriction then it will have an adverse effect as the engine has less mechanical advantage.
Probably not. As we saw with the direct drive, the engine could be run at, hmm, let's just say very fast, without the pump giving a huge output. Geared up, the pump is giving a good flow rate at modest engine rpm with very little head, and we are told the engine is well on top of that delivery at this gearing.

Centrifugal pump behaviour is nothing like a positive diplacement pump. From no head, or next to none, as we have here, as the head is increased, the pump will come into its 'design' range, where, for a given shaft speed, flow rate x head is maximised. This is the condition at which it will absorb the greatest power (at that speed) even though it is working at its best efficiency. Note also that flow rate x head = power output. If the head is increased further, the flow will start to decrease faster than the head increases, and the power absorbed will be less.

Increase the shaft speed, and the pump will deliver greater flow at no head, and greater head at no flow. If you increase head and speed commensurately, so as to stay on the max efficiency duty, then the power absorbed increases as the cube of the speed. Roughly, the flow is proportional to the speed and pressure proportional to the square of the speed.

All of the above is generalisation, and describes a pump that is well behaved. Some designs can be unstable under certain conditions. The Stuart No 1 has design peculiarities, but I don't have much idea as to how they would affect the performance characteristics in practice.

Offline Zephyrin

  • Full Member
  • ****
  • Posts: 628
  • near Paris, France
Re: Stuart No1 centrifugal pump
« Reply #34 on: December 09, 2021, 06:32:22 PM »
you may easily estimate the work and power done by the pump, with an amount of water lifted to a measured head, in a definite time...and compare the different conditions.

this is really a beautiful and efficient pump !

Offline john mills

  • Full Member
  • ****
  • Posts: 315
Re: Stuart No1 centrifugal pump
« Reply #35 on: December 09, 2021, 07:23:04 PM »
I have a stuart no 2  i have it direct coupled to the virus engine  with it drives with ease. the engine is 1" bore and stroke twin single acting
the no 2 pump is larger 3/4" inch pipes. i would think the engine you have would have plenty of power with the gear box to drive the pump
at a reasonable speed with out the engine having to rev as fast as the pump needs .you will find when you try it.
     John

Offline Steamingandy

  • Full Member
  • ****
  • Posts: 40
Re: Stuart No1 centrifugal pump
« Reply #36 on: December 09, 2021, 07:44:34 PM »
The pump will be supplying the cooling water for the condensers, it is an open circuit, so only the restrictions is the pipe work so I think this will copy happily.

Offline Steamingandy

  • Full Member
  • ****
  • Posts: 40
Re: Stuart No1 centrifugal pump
« Reply #37 on: December 14, 2021, 07:51:30 PM »
All finished ticks over nicely
<a href="https://www.youtube.com/watch?v=6T_8E-L0Kto" target="_blank">http://www.youtube.com/watch?v=6T_8E-L0Kto</a>

Offline RReid

  • Full Member
  • ****
  • Posts: 826
  • Northern California
Re: Stuart No1 centrifugal pump
« Reply #38 on: December 14, 2021, 08:10:31 PM »
That's lovely work all around. Well done! :ThumbsUp: :cheers:
Regards,
Ron

Offline crueby

  • Full Member
  • *****
  • Posts: 14477
  • Rochester NY
Re: Stuart No1 centrifugal pump
« Reply #39 on: December 14, 2021, 08:28:30 PM »
The pump and engine are well matched now, love it!  Just noticed what I think is a boiler feed water pump on the left end of the engine as well.   :ThumbsUp: