Quote:
Originally Posted by Dale M.
According to Justin (Oxygen Plus) there is a internal check valve (BFP) on concentrators under the cover .........
Dale
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Thanks Dale. I was unsure of the Devilbiss. We have experimented with various poppet and ball type exterior mounted check valves, searching for the proper combination that would ensure
any oxycon could succesfully gang with
any other oxycon. We used valves with crack pressures from 2"WC to 5 psig, and rated for operating pressures to 100 psig. The vision was a wall of used oxycons... say 10 units... putting out 50-75 LPM (~100-150 CFH) at ~7.5 psig. All working in unison, and with only as many as needed operating (1 to 10 units). In the end we found two things.
1. The oxycon's internally mounted check valve, commonly referred to as a back flow prevention valve, would prevent return flow at pressures up to 125 psig. The valve is generally a push fit hose-to-barb connection, and on some machines it did not have a clamp at that connection. At approximately 25 psig back pressure (valve locked) the hose-barb connection disengaged. This actually is good... before the back pressure could reach 125 psig the system 'safed itself', venting the back flow... although this probably was not a intentional oxycon design feature
. However, it does require opening the unit to reconnect the hose and valve.
2. After various equipment (Invacare - AirSep) and valve configuration tests, it turned out that the way to enable any number of oxycons to chain-gang to any other oxycon was a simple, external modification to the oxygen hose, and required no parts -- thus with nothing to 'sell' there was no potential profit reason to pursue it. As a plus, it also prevented the condition which leads to auto-shutdown (and alarm) from occuring if the torch oxygen valve is closed and remains closed while the oxycon is operating. The oxycon (or gang of several) is operated like a 'virtual oxygen tank'. The 'tank valve' is the oxycon on/off switch; the 'pressure regulator' is the flow valve. No need to remember to open and reopen the torch oxygen valve to prevent an alarm.
Me
(p.s... yes
we know that pressure regulators, and flow regulators are not the same -- it's just an analogy).