Hi George ,

I am writing this at your request in the hope you can help someone else by whatever means you have available. To start with my father in law is a nice older man that is a decorated World War II vet that I have always got along with. About 11/2 years ago he started to get bronchitis over and over again the doctors didn't know why. It got so bad that he started to need O2 then he needed more O2 so a portable concentrator was rented from a medical supply store. This was the beginning of trouble he has been in and out of the hospital going on 3 times now. Each time he would go to the hospital and recover quickly then go home and end up having to go back. I  work as a Power Plant Electrician and am quite practiced at control systems old and new so I decided to troubleshoot this problem. Seeing as the trouble increased when the concentrator entered the scene this is what I suspected first.

 

Step #1

I called the medical supply store and asked when was the last time the unit was calibrated and the filters were changed. The reply was every 6 months and once a year on the filters.

They agreed to come out and check the unit over when they did they decided to swap the unit with another one and this was done.

 

Step #2

I had asked if the filters would filter out CO I was told yes it did and that it had an alarm that went off when CO was detected I asked if the alarm was looking at the output to the canula or after the filtration I was told after the filtration. I suspected CO because the house has Gas, a gas stove a gas boiler a gas hot water heater. I then asked if end of line testing was done to see what the unit was putting out I was told that a ozimiter was placed at the machine not at the end of the canula.

 

Step #3

I took a tri gas monitor to the house it measures O2,CO,HS2 I then made a end of line sensor using a plastic bag that I placed the canula and the monitor probe inside of. I first zeroed the monitor using clean outside air.

 

Step #4

I lit off the concentrator and watched the monitor there was no CO and O2 went to 93% it slowly dropped to 92.8% but no CO.

 

Step #5

I then lit off the stove the boiler and hot water heater at first there was no change then it slowly climbed 5ppm CO and stayed there.

 

Step #6

I then removed the monitor probe from the sealed bag and checked the probe zero using outside air again it went down to a nice zero when I placed it back in the bag it went up to 5ppm again.

 

Step #7

I then removed the probe and placed it where he sat the most it read 1to 2ppm CO in the room.

 

Step #8

He had intank air sitting there so I placed the probe in the bag and connected the canula to the air tank the monitor read zero CO also the inflation rate was greater even though the same flow rate was selected I later found that the line loss from the long tubing was the cause of the low flow rate after trouble shooting.

 

Step #9

I asked for history of where and when the concentrator was moved around and found out that it had been moved from the back bedroom to the kitchen about 10ft across from the newer gas stove this stove had electric igniter ignition not pilot lighted the unit was moved because of the lines needing to reach outside so he could sit outside.

 

Step #10

I moved the unit to the bedroom and checked the bag reading it went down to 1ppm CO the O2 stayed 92.8%

 

My findings are this the line size and length of the air tubes greatly affect the end result flow and a end of line inline flow meter is needed. Also the output pressure is lower from the concentrator than from the tank. The concentrator does just that it takes room air at 21%O2 and boosts it up to 95%O2. It boosts whatever it gets 4.5 times higher so 1ppm CO is boosted to 4.5to 5ppm CO there is no CO filter in this unit and the only current way to filter CO is green plants. In my opinion fresh air is the only way to make sure that the concentrator puts out no CO also these units are on the floor they need to be placed on a 2ft high table off the floor line. CO is heavier than air and will tend to lie in low spots in the room. Also the concentrators alarm for CO goes off at to high a level to detect low level CO. The people are being subjected to 5ppm for 24hrs 7days a week. And the Gas company and the health supply people do not know any better. Please get the word out to people that if they have loved ones on these machines and they have gas in the house to provide fresh air to these machines and get them off the floor. If I can help you in any way I will also do not give up on the low level CO monitors It is people like you that make the world a better place to be.

 

 K Z