CPAP Air Filters

[ejbpesca]

What about cutting a COVID 95 filter to the correct size? These filters must have been medically approved, and you should also select the manufacturer carefully.

That is a very good idea if cutting a section of an N-95 mask does not cause the material to fray.  I just heard about some filters available that are not fibers packed together they are paper-like sealed in a membrane.  The user also said they discolor which to me is evidence they work better than those that do not.  I was not given a source though.  

My earliest filters which were by Phillips had a membrane over something with no protrusion of fibers and after a month had gone from bright white to light gray.  It was not until generic filters for ResMed that I found them with loose fibers and no discoloration with use.  

[Hmm888]

After 4 days use the ResMed brand filter I am testing has begun to discolor.  The other brand of filters I have been using for a year do not discolor after a month of use.  I am asking the seller for a rating (MERV or other) of the filtering capabilities of their filters.

I received another brand of filter for testing today from an online CPAP supplies vendor.  It has visible fibers protruding from the edges.  

I got a private message from a moderator not to give a link to a vendor.  I never wrote a link nor the name of any CPAP vendor yet got a serious looking 2nd warning that I did)  I wonder if the warning was an automatic response due to the initials for durable medical equipment being written.  I'll use the term CPAP supplies vendor instead of to try to stay out of trouble.

I have yet to get an answer from my CPAP supplies vendor (is that better) to the question of whether they will send me ResMed filters as opposed to the defective ones I am getting.  

I found an online source for the ResMed brand for $6.50 each.  I will spring for those now if my CPAP supplies vendor refuses to send me them.

The discoloration factor is enough for me to realize I have been using defective filters.  May I start a thread called "Check Your Filters?"

No, the discoloration is normal. I can assure you. I expressed the same concerns as you when I purchased my AS11. The AS10 also discolored but not so quickly.

I'll only buy OEM not generic filters. Even online CPAP providers sell generic and often won't tell you. The AS10 hypo filter is not cut to spec and they gaslight their customers that even though the may be smaller than OEM they are safe to use — no they are not!

[G. Szabo]

That is a very good idea if cutting a section of an N-95 mask does not cause the material to fray. 

Perhaps the safest solution is to enclose the instrument hermetically in a chamber with a large window where one can tape or thread a full N-95 mask. This would resolve the unknown flow resistance of the N-95 filter. Our instrument cannot have too high an inlet resistance, and we do not know the instrument specification in this respect or the N-95 characteristic. Hence, a larger filter area could mitigate this issue.