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Stuart No1 centrifugal pump

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Admiral_dk:
Funny - in my minds eye - i feel that the vanes are mirrored to what I have seen so far ....  :headscratch:

 ..... but all parts looks great  :cheers:

pieterb:
indeed, Admiral is correct. the curve of the vanes should be in the other way.

Steamingandy:

--- Quote from: pieterb on November 27, 2021, 09:39:51 PM ---indeed, Admiral is correct. the curve of the vanes should be in the other way.

--- End quote ---
As per drawing?

Dan Rowe:
It is the photo of the impeller in the casing that is the issue generally the vanes face the other way see:
https://www.introtopumps.com/pumps-101/what-is-a-centrifugal-pump/

Cheers Dan

Charles Lamont:

--- Quote from: pieterb on November 27, 2021, 09:39:51 PM ---indeed, Admiral is correct. the curve of the vanes should be in the other way.

--- End quote ---
Well, that is what I would have thought too.

However, Stuart Turner were the Rolls Royce of small pump manufactures. (The main business areas were 2-stroke marine petrol engines and small pumps. Model steam engines was a sideline. The models business was eventually sold off as Stuart Models, and Stuart Turner remains as a pump manufacturer.)

The impellers on their electric centrifugal pumps were conventionally arranged with backward curving blades, but for some reason I don't understand, the pump casting kits used forward curved vanes. One reason for doing this might be that they were intended to be direct driven by relatively slow revving steam engines. Curving the blades forward normally creates a greater flow rate, at the expense of pressure.

Another odd feature of these pumps is they have no volute or diffuser space - the impeller fits inside the the circular case with only small clearances, so each space-between-the-blades can only deliver while it is beside the delivery port. For the other 5/6 of a turn, nothing much happens.

As someone who had some involvement with pump design during my career, I am at a loss to explain these design features, and am not going to waste our time on speculating, but you can be sure that S-T will have had good reason for adopting them.

 The text books (Anderson, Tuzson, Stepanoff etc) don't provide many clues for small pumps, where the hydrodynamic theory is increasingly overwhelmed by friction and viscosity effects. Steamingandy has (intuitively?) grasped this in polishing up the cast surfaces of the impeller.

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