What is the effective pore width of filters for CPAP machine

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
sleepy1235
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What is the effective pore width of filters for CPAP machine

Post by sleepy1235 » Sun Jan 19, 2014 2:45 pm

In response to this question I would like to see some links if possible.

What is the effective pore width of the filters for CPAP machines?

Effective pore width is the particle diameter at which the filter will remove the particle with some high efficiency. This is because most fluid filters use methods beyond mere physical blockage to remove particles. For example (High Efficiency Particle Absorption) HEPA air filter fibers charge up with air flow and remove particles much smaller than the physical distance between the fibers through electrostatic forces. This allows low resistance to air flow yet very small particle removal.

Various fluid filters use similar methods and then there is Vandervals attraction between particles and surfaces when they get into close contact.

I only mention the above so people understand there is a difference. The physical size might be 1.0 microns, but the particles could be very effectively removed down to 0.2 microns, depending on medium, filter design, etc. etc.

Amusingly enough every once in a while someone will use ionizers whose input accidentally gets upstream of a HEPA and the HEPA dumps its particles. If you have a room ionizer it would impact your HEPA air filter and probably impact the filter for the CPAP machine which likely works by the same principle. (Few filters in use actually use physical blockage.)

So what is the effective pore width of the filters for the CPAP machines?

I am not finding good information on the filters online regarding effective pore size.

http://www.cpapfiltersandsupplies.com/p ... _chart.pdf This is a classic chart of typical particle sizes.

For a filter to remove viruses its effective pore size has to be really small, that is 0.01 microns, or 100 nanometers. For a specification of a filter I would very much like to see the specification for particle size and percent removal, and not some general statement that it removes a percentage of a specific type of contaminate.

Knowing the effective pore size would allow people to assess the impact of the filtration.

The CPAP filter is very likely way more effective than your nose and so the air should be cleaner using a CPAP machine than if you didn't have a CPAP machine,excepting due to some internal contamination source like mold or bacteria in the machine.

There is evidently different types of CPAP filters available. if you have a room HEPA I don't know if you really need a CPAP filter that can remove pollen, the HEPA should work very well at removing allergens.

I would think that the CPAP would help you not get lung infections depending on its pore size assuming it was clean and wasn't a source in itself.

Incidentally, HEPA filters generate what is white noise ("white" means it has an even sound frequency spectrum.) White noise helps mask the type of sounds that wake people up. So maybe a HEPA might help mask the sound of a CPAP machine, though not a spouse complaining about the CPAP machine noise but I digress.

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Julie
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Re: What is the effective pore width of filters for CPAP machine

Post by Julie » Sun Jan 19, 2014 3:13 pm

Most machines have a gray foam filter and some have an additional white filter for smaller particles, allergens, etc. I would think the makers of the machines have done some research about effectiveness of filters as they've used them for years and are obviously well aware they're being used for breathing machines.

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Goofproof
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Re: What is the effective pore width of filters for CPAP machine

Post by Goofproof » Sun Jan 19, 2014 3:17 pm

Some are sized to remove some pollen particals, ultra fine, but they aren't in the hepa filter range. I don't know where you would find micron ratings, as there are so many varients out there, most likely real world data would have little bearing on what you buy, the supplier will give you what he has around. Jim

The body does the job of filtering your air intake in the daytime, requirements don't change at night.
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LSAT
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Re: What is the effective pore width of filters for CPAP machine

Post by LSAT » Sun Jan 19, 2014 3:32 pm

Goofproof is absolutely right. You breathe this air all day without filtering it...why is it more important at night? Besides...as I understand it, the filtering is more to protect the inside of your machine than for your health.
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sleepy1235
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Re: What is the effective pore width of filters for CPAP machine

Post by sleepy1235 » Sun Jan 19, 2014 3:41 pm

Organic material that gets through the filter can then reside in the machine and be a source medium for fungal or bacterial growth.

I use deionized water systems and we always have issues of bacterial growth in the plumbing.

So it is to protect the machine.

If you have a HEPA you can have clean air with and without the CPAP.

Wulfman...

Re: What is the effective pore width of filters for CPAP machine

Post by Wulfman... » Sun Jan 19, 2014 3:47 pm

LSAT wrote:Goofproof is absolutely right. You breathe this air all day without filtering it...why is it more important at night? Besides...as I understand it, the filtering is more to protect the inside of your machine than for your health.
Yep! The OP is focused on the wrong criteria.
Besides, anything coming into the machine that gets past the intake filters will get dumped into and left behind in the water in the humidifier chamber. Water molecules are too small to carry anything out of the HH chamber to the user.


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JDS74
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Re: What is the effective pore width of filters for CPAP machine

Post by JDS74 » Sun Jan 19, 2014 5:09 pm

Wulfman... wrote:Yep! The OP is focused on the wrong criteria.
Besides, anything coming into the machine that gets past the intake filters will get dumped into and left behind in the water in the humidifier chamber. Water molecules are too small to carry anything out of the HH chamber to the user.
Close but not cigar. The intake air passes over the water in the humidifier in most if not all CPAP humidifiers and picks up moisture that has evaporated from the water supply. Anything that is particulate and airborne in this process can be passed out to the patient. Some particulates do get trapped in the water chamber but not all.

Put a bacterial filter on the output side, let it run for a month and then look at the filter. Where do you suppose all that grey stuff comes from?
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pbriggs
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Re: What is the effective pore width of filters for CPAP machine

Post by pbriggs » Sun Jan 19, 2014 5:29 pm

I did not find any actual specifications, but this site says that it removed 99.99% of bacteria - but it does not specify the bacteria and that they are electrostatic charged
http://www.cpapfiltersandsupplies.com/f ... afine.html

for inline filters - this might be of interest:
http://www.gulcanlarmedikal.com.tr/pdf/ ... Filter.pdf
starting on page 6 they give some very detailed information on filteration

Wulfman...

Re: What is the effective pore width of filters for CPAP machine

Post by Wulfman... » Sun Jan 19, 2014 5:34 pm

JDS74 wrote:
Wulfman... wrote:Yep! The OP is focused on the wrong criteria.
Besides, anything coming into the machine that gets past the intake filters will get dumped into and left behind in the water in the humidifier chamber. Water molecules are too small to carry anything out of the HH chamber to the user.
Close but not cigar. The intake air passes over the water in the humidifier in most if not all CPAP humidifiers and picks up moisture that has evaporated from the water supply. Anything that is particulate and airborne in this process can be passed out to the patient. Some particulates do get trapped in the water chamber but not all.

Put a bacterial filter on the output side, let it run for a month and then look at the filter. Where do you suppose all that grey stuff comes from?
You're just makin' up "stuff".........
(copy the link and take out the spaces and download the study)

http : // journal . publications . chestnet . org/pdfaccess . ashx?ResourceID=2117327&PDFSource=13

"Sterile Water Is Unnecessary in a Continuous Positive Airway Pressure Convection-Type Humidifier in the Treatment of Obstructive Sleep Apnea Syndrome*"


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msla
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Re: What is the effective pore width of filters for CPAP machine

Post by msla » Sun Jan 19, 2014 5:44 pm

It looks like OP has a Resmed S9 pictured. With my machine I find that there are some particles of dust that escape the filter by going around the edge of the filter. Therefore, my answer is that anything that can get past the edge of the filter and the S9 housing can get much farther through the machine. I change my filter monthly and have dust lodged on the S9 case near the perimeter of the filter.

If an extremely clean air supply is desired, then, perhaps, placing the CPAP nto a tightly sealed box with appropriate ports for power, air, air hose, access, and HEPA filtration is a solution.
Last edited by msla on Sun Jan 19, 2014 8:27 pm, edited 1 time in total.
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Goofproof
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Re: What is the effective pore width of filters for CPAP machine

Post by Goofproof » Sun Jan 19, 2014 6:32 pm

JDS74 wrote:
Wulfman... wrote:Yep! The OP is focused on the wrong criteria.
Besides, anything coming into the machine that gets past the intake filters will get dumped into and left behind in the water in the humidifier chamber. Water molecules are too small to carry anything out of the HH chamber to the user.
Close but not cigar. The intake air passes over the water in the humidifier in most if not all CPAP humidifiers and picks up moisture that has evaporated from the water supply. Anything that is particulate and airborne in this process can be passed out to the patient. Some particulates do get trapped in the water chamber but not all.

Put a bacterial filter on the output side, let it run for a month and then look at the filter. Where do you suppose all that grey stuff comes from?
It comes down to the States of Matter. Your nose and airway are made to remove partials that we breath every day, they usually work for a normal lifetime, unless we fill them with something stupid. In normal use Don't Matter applies. Unless you require a HEPA filter 24/7, why would you need one 7/7... In real life their are more important things to worry about. Jim
Use data to optimize your xPAP treatment!

"The art of medicine consists in amusing the patient while nature cures the disease." Voltaire