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Bob Weisner
08-03-2005, 12:56 PM
Hi.

What would be the best pitch or curve for a fan blade that is in a dry kiln. Trying to reduce the noise from the fan blades.

Thanks,
Mike Weaver
08-03-2005, 1:19 PM
Bob,
As to pitch, I can't even guess, but i would suspect that slowing a fan down some would reduce noise a good deal...

Of course, moving enough air in the end would still be needed.

Sorry I can't be more help,
-Mike
Lee DeRaud
08-03-2005, 1:23 PM
What would be the best pitch or curve for a fan blade that is in a dry kiln. Trying to reduce the noise from the fan blades.
Four-seam fastball, up and in.:cool:

Seriously, sounds like what you want is high volume, low velocity: wide, steep-pitch blades, keep the speed down as low as possible. Most of the noise from fan blades is turbulence off the tips. Think "ceiling fan", not "dust collector".
Mike Weaver
08-03-2005, 2:01 PM
Four-seam fastball, up and in.:cool:

Seriously, sounds like what you want is high volume, low velocity: wide, steep-pitch blades, keep the speed down as low as possible. Most of the noise from fan blades is turbulence off the tips. Think "ceiling fan", not "dust collector".

Yeah, *that's* what I meant to say...:D

Cheers,
-Mike
James Ayars
08-03-2005, 2:12 PM
One thing I noticed with the fans in our gym is that the fans with the entire blade at an angle make the least noise. The fans that have flat blades with just the edges pitched are quite noisy.
James
Carl Eyman
08-03-2005, 2:17 PM
The fans in our gym make a lot of noise when the team's winning.
James Ayars
08-04-2005, 4:12 PM
I give you an A+ for that one carl.;)
Ian Abraham
08-04-2005, 5:05 PM
Pitch will certainly come into the equation, but it's probably not the complete answer. The best thing to reduce noise it to go to a larger fan and spin it slower. It will take about the same power, and move about the same amount of air, but noise will be MUCH less.

Downside - bigger fans cost more

Ian
James Ayars
08-04-2005, 5:47 PM
We replaced most of our 24 and 36 inch direct drives with 42 inch belt drives. They're a lot quietier and and still pull less than 10 amps.
Dale Thompson
08-04-2005, 9:53 PM
Hi.

What would be the best pitch or curve for a fan blade that is in a dry kiln. Trying to reduce the noise from the fan blades.

Thanks,

Bob,
Air moving through a fan should not make any other noise than just a "whoosh" sound from the fan meeting the air. That is unless your blades are pushing air at a velocity beyond the speed of sound. :eek: I would guess that the torque of your fan motor is creating a "side force" on the bearings or bushings of the fan shaft and causing the objectionable "noise". ;)

As has been said, you can turn down the speed. :) Another thought is that you could try lubricating the motor/fan bearings. :cool: Don't over do it or you will burn out the motor.!! :(

Dale T.