[C320-list] Changing the Impeller

[Donald Lawson]

Warren is correct. Rotation speed is the main factor in flow rate. However a 10 blade will push slightly less water than a 6 blade due to the additional 4 blades taking up  more volume inside the pump. Each blade has slightly less water to push in a 10 blade. It is negligible. Might be that each blade, of a 10 blade, pushing less water will increase durability of the blades?
Don Lawson #1005
On May 12, 2012, at 6:12 PM, Warren Updike wrote:

> I am an aficionado of the Globe "Run Dry" impellers (Defender.)  I posed the
> same question to them and they said the 6 blade and 10 blade are
> functionally equivalent.  If you think about it, the volume of the area
> inside the pump and rotation speed are the main factors.  6 or 10 blades
> won't make much of a difference in the flow.  
> 
> Warren & Pattie Updike
> 1994 C320 #62 "Warr De Mar"
> 
> -----Original Message-----
> From: Mark Gillingham [mailto:markgill at uwalumni.com] 
> Sent: Friday, May 11, 2012 8:32 PM
> To: C320-List at catalina320.com
> Subject: Re: [C320-list] Changing the Impeller
> 
> Another pump question. I was able to get a Jabsco impeller that says it is a
> replacement for Johnson 810b and is the correct dimensions with a screw for
> the slotted shaft, but it has 10 blades rather than 6. Do the number of
> blades matter if the other dimensions are correct?
> 
> Mark
> Speakeasy #612
> 
>