CamVac noise reduction with a baffle tube

[Eric The Viking]

...having the uninterrupted straight path for the air-flow I think is really important

I very much doubt it matters. What is important is not creating excessive back-pressure. If overall the outlet (available for airflow) diameter increases with respect to the spigot on the machine, it should be fine.

The higher the frequency of sound, the more directional it is & the more it is attenuated (reduced) by the environment, e.g. distance in dry air, walls, soft surfaces, etc.). The motor isn't stressed by noise suppression, only by stalling and overheating. You're not doing either of those things.

I've only had a vac motor fail once, which was when our cleaner, who's wonderful in every other respect and very mechanically adroit (she comes from a family of amateur mechanics), mistook our vac for a wet+dry variety and soaked the motor. It still ran for several years afterwards, but the damage was done and the bearings eventually failed.

I do clean out my Earlex motor's impellor, about once or twice yearly, as crud builds up on the vanes, and that unbalances it and reduces its efficiency, causing overheating. A very nice Mr. Maskery recently provided me with a cyclone, so once that's working for things like the chop saw and the router table, it probably won't need much attention at all. When it's dirty it does get VERY noisy though - it really screams to let me know. I'm expecting that it's eventual failure will be bearings, although it might be brush/commutator wear.

I assume the Camvac has brushed, i.e. "universal," motor(s). Is that correct?

 

[dedee]

Very interesting, thanks very much for sharing. I have a twin motor Camvac and the luxury of it being outside and above the workshop which gave me plenty of room for for a 200l drop box with cyclone on top. Even so the noise within the barn is not pleasant and as I have plenty of space to run either vertical like yours or even horizontal baffles I will save this for future reference. Standard pipe diameter over here is 100mm rather than 110mm but it is easy enough to have some "shipped".

Can I ask you where you bough the accoustic foam? Is it a standard shape/thickness?

 

[Moonsafari69]

I do clean out my Earlex motor's impellor, about once or twice yearly, as crud builds up on the vanes, and that unbalances it and reduces its efficiency...
I assume the Camvac has brushed, i.e. "universal," motor(s). Is that correct?

I've not considered cleaning the motor vanes, that's a good point. This one has been running for a couple of years now so would probably benefit from a blast from the compressor to clean it out.

Yes, the motor is c 1kW and uses carbon brushes.

 

[Doug B]

An excellent idea, beautifully presented. All noted for the future.

Thanks Duncan. The all in cost for parts was £20, a decent return for the price.

Really like your baffle & would like to make one for my own Cam vac as I have everything other than the acoustic foam, could I ask where you sourced this as a quick Google suggests it will cost almost £20 just for foam?

Thanks for sharing, anything that reduces sound in the workshop is a bonus =D>

 

[Moonsafari69]

Very interesting, thanks very much for sharing. I have a twin motor Camvac and the luxury of it being outside and above the workshop which gave me plenty of room for for a 200l drop box with cyclone on top. Even so the noise within the barn is not pleasant and as I have plenty of space to run either vertical like yours or even horizontal baffles I will save this for future reference. Standard pipe diameter over here is 100mm rather than 110mm but it is easy enough to have some "shipped".

Can I ask you where you bough the accoustic foam? Is it a standard shape/thickness?

Hi dedee, your set-up sounds great, if the pipe is 100mm 'internal' diameter then that should be ok. For the foam you really need the 20mm thick variety (most of it is 40mm thick). If you do a search on Ebay UK for "8 Tiles Acoustic Foam Panels Sound Treatment Convoluted Egg Profile" this will take you to the right place. See below too:

Can I ask where you sourced this as a quick Google suggests it will cost almost £20 just for foam? Thanks for sharing, anything that reduces sound in the workshop is a bonus =D>

dedee & Doug, this should help for the 20mm foam:

 

[woodpig]

I very much doubt it matters. What is important is not creating excessive back-pressure. If overall the outlet (available for airflow) diameter increases with respect to the spigot on the machine, it should be fine.

The higher the frequency of sound, the more directional it is & the more it is attenuated (reduced) by the environment, e.g. distance in dry air, walls, soft surfaces, etc.). The motor isn't stressed by noise suppression, only by stalling and overheating. You're not doing either of those things.

I think you're right. Baffles are an accepted way of reducing noise. Car exhausts are a common example. I would expect a box labyrinth as the one linked earlier to not only provide good noise reduction but also be more compact.