Discussion in 'General Discussion' started by Josh_JK, Aug 13, 2013.
lychee that, just use some foil backed bubble wrap!
I was thinking about exactly the same thing on mine, found this link.
What do you reckon?
cover it in dynamat...
The correct terminology is 'Sound Moderator', thats what they are, there's no such thing as a 'Silencer', how do I know? I screw them on the end of the barrel.
Slightly different application there @Wireless
Those should be pretty good, but I'd be tempted to order one, try it and if it works make another one up with a couple of modifications. Ideally you want the gas to expand gradually, (think 2 stroke motorcycle expansion chamber) but it probably won't make that much of a difference. I'll tell you what I'll do...seeing as I've got my propex set up for testing, I'll order one and let you know the results...
My only reservation is that it's 100mm, and ideally a straight-through for 60mm could do with being smaller. Might work, might not.
Scratch that....they want £12.50 for delivery, so what was a £25 experiment would end up being £41 including charges. I could buy enough ALI and polyfill to make about 6 for that price
You know you want one....
just think....quiet heat....Jap blanket heaven
While your at it, design something which can duct the last three minutes of cold air overboard. It's annoying that when the propex has the van lovely and toasty it switches off and then proceeds to blow cold air into the van for the next three minutes.
Does yours recycle the cabin air Bob?
Ummm! Yes I think, both inlet and outlet are inside the van. Beside each other.
I tend to be in bed when I switch it off, otherwise I keep my feet out of the way, but it doesn't seem too bad.
Beats a gas fire in my book!
id make sure you you have got clearance as they are 100mm bigger than con size also that you use same size duct as conn on silencer , also those short ones are are only normally used a crosstalk so might not be up to much continuous if you get my drift , noise is one reason thats put me off ta be honest along with gas price.
Shame, not a bad idea though, I'll take one of those 6....
Any other thoughts on making it quieter?
I'm working on it....
the biggest intrusion is the high note from the fan itself, as most of the duct noise can be reduced to an acceptable level, without sacrificing air flow. If you keep increasing the duct length (which lowers the frequency of the sound to a less intrusive pitch), it then becomes a convoluted install. I'm trying to come up with something that you could tack close to the inlet and outlet that wouldn't take up too much space.The only way I can think of reducing the higher fequencies from the fan would be to tinker with the blades, or fit a quieter fan...which is much more involved. This is the kind of thing we'd make for the ducting in the studios I used to work in. Each time the air turns a corner, it sheds some of the sound energy as heat. A baffle like this would be lined with 'Profile' (egg-box foam).
The beauty of this type of 'silencer' was that it doesn't restrict air flow...
Something on these lines could be made more compact (but more expensive) than the straight-throughs you linked to....
Hmmm, yes, i though that most of the noise was from the fan, and a longer`run would help, I had seen cheap digital dB meters for like £25 on eBay, granted they may not be 100% accurate, but at least consistency when testing. When i get a min, I'll look for a air flow meter too....
Though in my application, space could be tricky, when i get a minute, I have x2 6 volt Trojan deep cycle batteries to shoehorn somewhere under the bed where the propex sits....I think 210aH along with the 80W solar should run things smoothly for a while...
Will be interesting to see what else you can figure out.
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