Dual Concentrators Question

Cyndi · #1 2006-07-31, 2:14pm

I'm hoping someone here will have a suggestion to solve my problem...
I (usually) run 2 concentrators with my mini cc torch, one is an AirSep purchased about a year and a half ago from Suncoast- the other is a Mobilaire V that was generously given to me- they both are 5 lpm. hooked together with a Y connector. The older "donated" one keeps shutting off and sounding the alarm randomly -the alarm on the newer one seems to have died but I think (and hope) it would shut itself off if something was wrong. After a bit of investigation the older one seems to run fine until I hook the hose to it. I can get 5 lpms until I plug the hose onto the front of it- then it drops to zero. Is it hooked up wrong? For some reason now the Y connection seems to be restricting the airflow. I've checked both hoses and there are no kinks. I can run my cc on one concentrator but the knobs get very hot and it seems to work much better on two. Any suggestions??

Three Muses Glass · #2 2006-07-31, 3:39pm

Did you check those filter thingies? Mine get grunged up with garage dust pretty quickly and the alarm will start up.

Cyndi · #3 2006-07-31, 4:57pm

The foam filters that are accessible from the outside? I do check and swap those often. I keep a spare or two so I can wash them. It will run fine until I hook the hose to the front port to run the oxy to the torch (via the Y connection) then the psi drops to zero...

oxydoc · #4 2006-07-31, 5:27pm

Quote:

Originally Posted by Cyndi

The foam filters that are accessible from the outside? I do check and swap those often. I keep a spare or two so I can wash them. It will run fine until I hook the hose to the front port to run the oxy to the torch (via the Y connection) then the psi drops to zero...

Check and see if the oxygen valve is open on your torch. If you hook it up to the oxycon closed, it will cause the ball to drop to zero. jack

Cyndi · #5 2006-07-31, 9:31pm

Quote:

Originally Posted by oxydoc

Check and see if the oxygen valve is open on your torch. If you hook it up to the oxycon closed, it will cause the ball to drop to zero. jack

It was open- the other concentrator was running. Could the force of air from one concentrator be possibly blocking the air from the other?

Justin L · #6 2006-08-01, 10:39am

doubt it, but it definitely sounds like there is an obstruction in the y connector somewhere. Maybe time for a new y connector?

oxydoc · #7 2006-08-01, 4:52pm

Quote:

Originally Posted by Cyndi

It was open- the other concentrator was running. Could the force of air from one concentrator be possibly blocking the air from the other?

Hey Cyndi, try hooking the concentrator up to the torch without the Y connector. And without the other oxycon. This may tell you whether or not there is a ploblem with the unit or the hoses. jack

lbjvg · #8 2006-08-02, 8:09am

Perhaps there is too much back flow pressure from the other machine. The machines supposedly have built in back flow checks but perhaps it is not functional. You can purchase check valves that insert between the machine and the Y connector (http://www.usplastic.com/catalog/cat...name=45&Page=1)

bhhco · #9 2006-08-02, 10:13am

Quote:

Originally Posted by lbjvg

Perhaps there is too much back flow pressure from the other machine. The machines supposedly have built in back flow checks but perhaps it is not functional. You can purchase check valves that insert between the machine and the Y connector (http://www.usplastic.com/catalog/cat...name=45&Page=1)

Yes it does appear the pressure/flow from one oxycon (probably the AirSep @ 6-7 psig) is back pressurizing the other oxycon (the Invacare Mobilaire V @ 5 psig).

The back flow check valve in the Invacare is probably working properly and is closing as it is designed to do due to back pressure from the AirSep. When closed, that same back flow check valve also restricts oxygen outflow - thus reducing oxygen outflow to zero, or at the least, significantly restricting outflow from the oxycon to below the minimum alarm/shutdown tolerances (sometimes preset at <0.25 lpm flow), resulting in an alarm/shutdown.

Essentially, when the oxycon's back flow check valve closes, nothing goes into, and nothing comes out of, the oxycon's oxygen supply connection until the back pressure is removed - then the valve will automatically open. However, if the back pressure situation lasted "too long", the oxycon may have shutdown, and even with a automatic opening back flow check valve , no oxygen would flow from the shutdown oxycon.

CAVEAT
This applies to AirSep Elites and Invacare Mobilaire V oxycons. It may or may not apply to other brands/models of oxycons, but I do not know that for certain.

Bill

p.s. I make no terminology distinction between concentrators, generators, etc.. To me they are all oxycons. They all concentrate oxygen. Some do a little - some do a lot - some do a whole lot. Some are old medical units - some are new - some are newly designed specifically for flamework (sort'a). But they all concentrate oxygen out of thin air.