I think small percentage of you might find this interesting. For those that don't, please consider this a caution. I am refurbishing a spare oxygen concentrator for a family member. DISCLAIMER: For those that their life depends on reliable concentrated oxygen, it is never a smart idea to buy one used and expect it to be your primary machine unless you send it off for professional service and re-certification. However for those that are renting a primary machine from medicare, and have a good backup supply of oxygen tanks, the risk of buying a used machine for traveling / other homes / camps, this risk can be minimized.
One typical downside to a used machine, is the interior of the unit typically has acoustic foam to lower the sound. This foam tends to absorb tons of smells such as; pet, mold, cooking odors (curry), and air freshener smells. During refurbishing, it is wise to gut the old nasty, decomposed foam and discard it, then re-line the interior with fresh new acoustic foam and a water based, non VOC adhesive. This is typically how the bio med companies do it.
Here is where it gets interesting. Many people think that there are HEPA filters inside the machine to make sure the patient is breathing ultra filtered oxygen. This is not really the case. There is a very coarse primary gross particulate filter to keep the machine somewhat clean inside, then a secondary HEPA filter to pre filter the intake air to the compressor, then after the air travels thru the sieve beds, there is a final bacterial micro disk filter to protect the patient. (Incorrect theory of operation removed by fordiesel69) see mk378's reply. It is explained much better.
The machine I purchased for cheap, even after gutting the nasty foam out, the pure oxygen discharging from it still smells a little bit like the glade plug in air fresheners their house was littered with. This is very alarming as if these odors are able to make it thru the sieve beds, then whatever these air fresheners are made out of, must be extra toxic to us. To think we are breathing in these chemicals that even zeolite sieves cannot filter out at the picometer level, tells us that the molecules are very tiny, and are breaching our blood / oxygen barrier. This should be cause for alarm.
I will be sending off the sieve beds for a repour. A company will dump out the old zeolite, and refill with new, and then test and recertify them.
One typical downside to a used machine, is the interior of the unit typically has acoustic foam to lower the sound. This foam tends to absorb tons of smells such as; pet, mold, cooking odors (curry), and air freshener smells. During refurbishing, it is wise to gut the old nasty, decomposed foam and discard it, then re-line the interior with fresh new acoustic foam and a water based, non VOC adhesive. This is typically how the bio med companies do it.
Here is where it gets interesting. Many people think that there are HEPA filters inside the machine to make sure the patient is breathing ultra filtered oxygen. This is not really the case. There is a very coarse primary gross particulate filter to keep the machine somewhat clean inside, then a secondary HEPA filter to pre filter the intake air to the compressor, then after the air travels thru the sieve beds, there is a final bacterial micro disk filter to protect the patient. (Incorrect theory of operation removed by fordiesel69) see mk378's reply. It is explained much better.
The machine I purchased for cheap, even after gutting the nasty foam out, the pure oxygen discharging from it still smells a little bit like the glade plug in air fresheners their house was littered with. This is very alarming as if these odors are able to make it thru the sieve beds, then whatever these air fresheners are made out of, must be extra toxic to us. To think we are breathing in these chemicals that even zeolite sieves cannot filter out at the picometer level, tells us that the molecules are very tiny, and are breaching our blood / oxygen barrier. This should be cause for alarm.
I will be sending off the sieve beds for a repour. A company will dump out the old zeolite, and refill with new, and then test and recertify them.
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