help needed with blower mods

O

Ozzieuser

New member
I would like to reduce the noise of the blower. I have read just about every bit of information on trying to reduce noise, however I have a few questions.
Is there a 'best' shape for the piece of material that you add as the second gore point ? seems to me that a square block is very abrupt to the air flow.
Also is there any benefit by varying the height of the impellor within the blower housing? ie: as close to the motor plate. ( assuming that the unit is only collecting dust and not chucks that could get stuck?)
Are there any other changes worth considering? I want to reduce the noise of the blower as a first point, then work out from there.
I have a simple sound meter to test any changes.

Thanks for any response.
 
I presume you are referring to the content of this thread when you are speaking about the material at the second gore point. As you can read there, the "stick" has specific dimensions and yes, it has sharp corners. If I recall correctly, Matt and Ed Morgano arrived at the shape and position for this by trial and error, but it was based on test results and showed a very significant sound attenuation of 10 decibels. I do not think that changing the cross section shape will improve that level of attenuation without the use of expensive test gear.

If you move the impellor, you will constrict the airflow and reduce the performance of the blower. I would recommend that you use other means to attenuate the sound (e.g., build a closet and use acoustic lining materials; or use a muffler on the exhaust side of the blower before air enters the filters).
 
thanks for the reply. It would be nice to know if they tried any shape that achieved the same reduction in noise but 'perhaps' was less of an obstruction to the air flow. I am thinking of more of a ramp up to a sharp point. Without any extra info to go on, I may try some experiments myself.

I am thinking of also adding a muffler, however before I start building anything I would like to find out which is the best way to achieve the most reduction without wasting too much time and materials.
 
Ozz - a while back I became interested in this and sent this in a PM to Matt & Ed. I'm an engineer and was so interested in it I did a search for blower housing sound reduction. I found two patents and one is very similar to the one that was discussed. The one almost identical is 5316439 and the other is 6575696.

cyclonehsg.jpg




Thanks,

Mike
 
Ozzieuser said:
Mike, many thanks for the info. Did you happen try any different shape with your blower?
Click to expand...

No I just used the wooden square block on mine. To tell the truth I really couldn't tell the difference (by ear). I did enclose the cyclone with mineral wool insulation and it made a huge difference.

Some experts at work say a Helholts resonator may work well on this application but I have never taken the time to look into it.

Mike
 
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