Register to reply

Materials and Particle Trapping

by icor1031
Tags: materials, particle, trapping
Share this thread:
icor1031
#1
Mar30-14, 05:39 PM
P: 11
Please excuse me if this isn't a physics question - I'm not sure where it belongs.

Felt, such as this: http://www.ebay.com/itm/Felt-by-the-...-/261301533508

And 3mil plastic sheeting, as this: http://www.homedepot.com/p/Husky-8-F...308C/202184057

--------

How small of a particle size, will those block?
For example: if I throw a .3 micron particle at the felt, will it go through?
How about the plastic?

Thanks!
Phys.Org News Partner Engineering news on Phys.org
Tricorder XPRIZE: 10 teams advance in global competition to develop consumer-focused diagnostic device
Study shows local seismic isolation and damping methods provide optimal protection for essential computing equipment
New filter technology uses inert gas to bore holes in high-quality steel
Baluncore
#2
Apr2-14, 01:09 AM
Sci Advisor
Thanks
P: 1,911
Assuming your medium is air and the 0.3 um particle is travelling slowly, it will not pass through the 0.003” plastic film, it will probably get caught up for some time in the felt. You could increase the chance of a particle being caught by the felt if you dampen the felt with oil or water. The felt is behaving like a HEPA filter.
See; http://en.wikipedia.org/wiki/HEPA
icor1031
#3
Apr2-14, 01:52 AM
P: 11
Appreciated, friend.

Baluncore
#4
Apr2-14, 03:46 AM
Sci Advisor
Thanks
P: 1,911
Materials and Particle Trapping

Note that felt is usually made from sheep's wool which has a diameter of about 20 um.
To reliably trap 0.3 um particles requires a fibre size closer to 1 um.
It is probable therefore that ordinary felt will only trap particles of 6 um and greater.
icor1031
#5
Apr2-14, 05:35 AM
P: 11
Quote Quote by Baluncore View Post
Note that felt is usually made from sheep's wool which has a diameter of about 20 um.
To reliably trap 0.3 um particles requires a fibre size closer to 1 um.
It is probable therefore that ordinary felt will only trap particles of 6 um and greater.
By chance, are you familiar with mass loaded vinyl? How would it do? :)

http://www.ebay.com/itm/2lb-Mass-Loa...item1c1ec473d8
Baluncore
#6
Apr2-14, 06:41 AM
Sci Advisor
Thanks
P: 1,911
Mass loaded vinyl will not pass air, let alone 0.3 um particles.

What are you trying to accomplish here?
How much area of filter do you need?

You can buy rolls of HEPA filter material such as these.
http://www.alibaba.com/showroom/hepa-filter-cloth.html
You can search for your local supplier.
icor1031
#7
Apr2-14, 06:47 AM
P: 11
Quote Quote by Baluncore View Post
What are you trying to accomplish here?
It's for making acoustic panels. The MLV is for diaphragm resonators, and the felt/plastic are for porous absorbers.
I'm probably going to fill both with Mineral Wool, and I want to avoid fibrosis. ;)

I asked about felt, as a possible alternative to plastic. But that won't work, as you pointed out.

Thanks again!
icor1031
#8
Apr8-14, 01:01 PM
P: 11
Quote Quote by Baluncore View Post
Mass loaded vinyl will not pass air, let alone 0.3 um particles.
I'm back, again. :)

My plastic sheeting (seems to be .31mil, not 2mil) is causing issues @ 2.5kHz, even with 1 layer of felt on top of it.


So, my question: How well will satin work to block particles? It says "100% polyester."
If that won't work well, is there a material that you would suggest?

Thanks!
Baluncore
#9
Apr8-14, 03:53 PM
Sci Advisor
Thanks
P: 1,911
I presume you are using the plastic film to stop glass dust escape.
What problems does plastic film cause at 2.5 kHz.

The thickness of plastic sheet will determine it's mass per unit area and resonance frequency.
It will behave differently if it has a crumpled surface or if it is bonded to the felt.

100% polyester satin is a woven polyester fibre, so it will probably not stop fine dust. You would need a bonded polymer film material such as is used to make car covers or disposable coveralls for contaminated sites. If it is waterproof it will probably stop fine dust.

Sound absorption comes from a sandwich of different materials with multi-faceted surface orientation. For example, used egg cartons glued to a surface can make a big difference.
AlephZero
#10
Apr8-14, 08:07 PM
Engineering
Sci Advisor
HW Helper
Thanks
P: 7,164
Quote Quote by Baluncore View Post
Sound absorption comes from a sandwich of different materials with multi-faceted surface orientation. For example, used egg cartons glued to a surface can make a big difference.
That is one method, but "flat" acoustic panels (often used as internal dividing walls in office buildings) basically work like a transmission line with impedance changes along its length, to let the energy get "inside" the panel and stop it getting out again.

The purpose of the filling material (rock wool etc) is to provide a huge surface area relative to the volume of the internal cavity, to absorb the kinetic energy (i.e. the sound) in the air into the viscous boundary layer in the air surrounding each individual fiber. Loudspeaker cabinets are filled with the same type of material for the same reason.
icor1031
#11
Apr9-14, 01:08 AM
P: 11
Quote Quote by Baluncore View Post
What problems does plastic film cause at 2.5 kHz.
The SPL is high, similar to not using a panel. I'm not sure about decay time, or anything else.

It's okay, it goes away if I use *two* layers of felt. :)

Thanks again, be well.


Register to reply

Related Discussions
Trapping electrons Atomic, Solid State, Comp. Physics 1
Particle Trapping General Physics 3
Yidun Wan's talk about new particle model from simple materials Beyond the Standard Model 0
Materials and particle coupling Beyond the Standard Model 1
Trapping Photons Quantum Physics 2