Chromatography Forum

Hi!
I have zero air generator "Dominick Hunter UHP-35ZA-S" and two gas chromatographs (dual-channel and one-chennel). So we have three FIDs in sum
I woud like to swinch the zero air line from balloon to generator. But there is a little problem: in user guide there is information about max flow (3,5 L/min), but no info about min output flow.May be some one have a practice with generator? Is it ok if the output flow would be about 350-400ml/min? Wouldn't this damage the internal heater?

Hi!
I have zero air generator "Dominick Hunter UHP-35ZA-S" and two gas chromatographs (dual-channel and one-chennel). So we have three FIDs in sum
I woud like to swinch the zero air line from balloon to generator. But there is a little problem: in user guide there is information about max flow (3,5 L/min), but no info about min output flow.May be some one have a practice with generator? Is it ok if the output flow would be about 350-400ml/min? Wouldn't this damage the internal heater?

You don't need to worry. Temperature of catalytic bed is regulated with electronic circuit according to real flow of air. There is relay switching on and off the heater so the temperature is high enough and of course not too high.

dblux_, thanks a lot for your attention!!!! Do you meаn, that heater doesn't work all the time?
But I still have some doubts.
In instraction there in a section about "excessive downstream temperature", and as a possible failt there is "the flow of air thruogh the generator is too low". So user have to verify that the flow rate matches that spacified in technical specification. There is only max output flow data.

dblux_, thanks a lot for your attention!!!! Do you meаn, that heater doesn't work all the time?

Exactly, althou my zero gas generator is Peak Scientific, I think all of them work similar, and are secured against overheating.

Mine has relay on electronic circuit board, red LED soldered near circuit board is "on" when current flows through the heater. User can't see how it works until front cover plate is removed. Newer generators may have PWM regulators instead of relay, but the idea probably has not changed

But I still have some doubts.
In instraction there in a section about "excessive downstream temperature", and as a possible failt there is "the flow of air thruogh the generator is too low". So user have to verify that the flow rate matches that spacified in technical specification. There is only max output flow data.

For ease of mind ask manufacturer if low flows won't be harmful to the generator.

Thank you for your reply! I'll try to contact with manufacturer!