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Anonymous Poster

Reducing Sound from Rotating Drum

10/09/2008 11:08 PM

Is there any surface treatment that can be done to reduce noise. I am thinking of roll on, brush on or spray on material.

The application is a rotating drum with knockers (hammer) on the feed end to dislodge build up inside the drum. The hammers will be enclosed with acoustic material which will reduce radiating noise. I want to reduce the noise that travels through the shell of the drum. Hence the query.

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Guru
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#1

Re: Acoustic Treatment of rotating drum

10/10/2008 6:19 AM

Hmm.....

Maybe it would do to reduce the effects of the noise. Many years ago a machine in a room with hard surfaces was giving off noise at 92dBA, intermittently. Lining the upper half of the room walls and its ceiling with marine acoustic foam sheeting, intended for engine compartments, reduced the noise to 84dBA intermittent. Worth trying?

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#10
In reply to #1

Re: Acoustic Treatment of rotating drum

10/15/2008 8:39 AM

Contact

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UNITED STATES
888-270-8555 Local 702-617-2710
HTTP://WWW.CYBER-BRIDGE-MARINE.COM

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#2

Re: Reducing Sound from Rotating Drum

10/11/2008 9:22 AM

To dampen the noise may make the hammers less effective in dislodging the build up. Some of the noise is due to the vibration of the drum by the strike of the hammer. This vibration is to shake the build up loose.

This may be an application where electronic sound damping device would due if the operation was in an enclosure.

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#3

Re: Reducing Sound from Rotating Drum

10/11/2008 9:51 AM

Try this http://silentcoating.com/sr_1000.html, we use it in engine rooms. It is expensive.

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#4

Re: Reducing Sound from Rotating Drum

10/12/2008 11:05 AM

You should make a FFT analysis of the noise May be a modification of drum stiffnes will change amplitudes. Any way a drum radiates energy so that the best ist reduce this amount by isolation.

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#5

Re: Reducing Sound from Rotating Drum

10/12/2008 8:33 PM
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#6

Re: Reducing Sound from Rotating Drum

10/12/2008 8:35 PM

Thanks to all you guys who responded.

Before taking the path of covering the hammer, Bull Horn was considered. This technology I understand is used in high speed fan application to dislodge buildup. The Bull Horn releases high frequency noise to rattle the build up. This frequency is not audible.

The supplier visited site and disregarded it as a possible solution.

I am now thinking of installing acoustic covering for a distance of 1.2 metres on both sides of the hammer.

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Anonymous Poster
#7
In reply to #6

Re: Reducing Sound from Rotating Drum

10/14/2008 12:20 AM

To all,

The product that claims to meet the requirement is Delta-dB for noise attenuation by dampning the frequency and Delta-T for thermal insulation and noise attenuation by absorption.

Damping is possibly not a good choice because the main purpose of hammering i.e to dislodge the buildup would be compromised.

You may want to visit www.mascoat.com

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#8
In reply to #7

Re: Reducing Sound from Rotating Drum

10/14/2008 3:00 AM

Dampening noise doesn't stop the vibration only the sound of it. It is not the sound of the clapper striking the drum and the resultant sound of the vibrating drum it's the physical vibration itself which dislodges the scrap, are ya getting this

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#9

Re: Reducing Sound from Rotating Drum

10/14/2008 3:01 AM

How large is the drum?

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#11
In reply to #9

Re: Reducing Sound from Rotating Drum

07/01/2011 3:11 AM

The drum is 35 metres long and 4.5 metres in diameter. Shell wall thickness 3/4 inch.

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