Chromatography Forum

Hello,

I am planning on using a LN2 dewar for liquid cooling on an Agilent 8890 with capillary columns.

Maybe this is a dumb question, but will I be connecting my regulator to the liquid valve? Where did you find your liquid regulator?

I called a supplier and they were confused when I mentioned a liquid regulator.

Thanks

You just need to figure out the plumbing to step down from your portable dewar to the cryo inlet. Instrument will take care of the rest.

Unless you tip the LN2 tank over, it should be sending gaseous N2 through the CGA fitting to whatever tank regulator(s) you have.

I only know this for liquid CO2. We had a direct insulated line from the dip tube of the CO2 tank to the GC. The GC controlled the valve at the oven directly. So I think; no you do not need a regulator for the liquid nitrogen dewar. I'm not aware either that a liquid nitrogen "regulator" could exist. Just a direct connection to an insulated line that goes to the cooling valve on the GC oven. The GC software directly controls the cryo valve that lets it into the GC oven. Also, I believe you need a different valve for CO2 than you do for LN2. The top of the dewar will have a valve and CGA fitting for gas use and a separate valve and fitting for withdrawing liquid N2; not to be confused with the third valve and fitting for filling the dewar.

You only need a gas pressure regulator if you are also using the dewar for gas.

Hello,

I am planning on using a LN2 dewar for liquid cooling on an Agilent 8890 with capillary columns.

Maybe this is a dumb question, but will I be connecting my regulator to the liquid valve? Where did you find your liquid regulator?

I called a supplier and they were confused when I mentioned a liquid regulator.

Thanks

For doing cryo cooling with liquid N2, you connect to the port on the dewar listed Liquid with a direct insulated line, do not use the one labeled gas with the CGA fitting. Normally the connection is a 1/4" line, normal swagelok connector at the instrument and whatever the fitting is at the dewar. Usually at the dewar they supply it with a flare fitting, but we always took that out and had one that adapted to 1/4" swagelok.

The dewar will control the pressure and it will stay low enough that you don't need an external regulator. If the pressure drops too low, then you have to open the valve labeled Pressure Building which will allow the Liquid to circulate and warm and the pressure will increase.

Hello,

I am planning on using a LN2 dewar for liquid cooling on an Agilent 8890 with capillary columns.

Maybe this is a dumb question, but will I be connecting my regulator to the liquid valve? Where did you find your liquid regulator?

I called a supplier and they were confused when I mentioned a liquid regulator.

Thanks

For doing cryo cooling with liquid N2, you connect to the port on the dewar listed Liquid with a direct insulated line, do not use the one labeled gas with the CGA fitting. Normally the connection is a 1/4" line, normal swagelok connector at the instrument and whatever the fitting is at the dewar. Usually at the dewar they supply it with a flare fitting, but we always took that out and had one that adapted to 1/4" swagelok.

The dewar will control the pressure and it will stay low enough that you don't need an external regulator. If the pressure drops too low, then you have to open the valve labeled Pressure Building which will allow the Liquid to circulate and warm and the pressure will increase.

I concur.