Chromatography Forum

I am interested in hearing what tricks people do to help the oven cool down faster between samples and I don't mean open the front door either. Who has time to do that?

Are the 5890 oven flaps in the back opening fully to let the hot air out? You should be able to see and feel this from the back. We've had to replace a couple of the motors for this, and even once rivet one of the circular flaps back on. Of course I'm assuming the oven fan itself is working.

sllimbri,

First, oven diverter to make sure hot oven air is not mixing with incoming air. Second, GC Racer has an accessory that blows air into 5890 oven to speed up cool down time. Third, there is an insert that HP used to sell that, if you had a rear injector and detector, took up oven space and improved cycle time. If you are rear injector and detector, or you can make it so, I will see if I can find the part number....

Best regards.

What temperatures from and to?. If near ambient, the liquid CO2 cooling accessory works very well to pull down near ambient temperatures, but it only starts at about 80 - 90C, from memory.

As others have noted, the back vent motors are quite effective, but are susceptible to failing unless shaft bearings are kept well lubricated.
Ensure that the instrument back is well away from any wall to facilitate separation of incoming and exhaust flows. In one case I adjusted the Air-conditioning unit grill to push cold air towards the bench, and thus into the lower back flap - made a little difference.

Bruce Hamilton

If this is a need worth spending money on, there are low thermal mass columns that actually sit outside the GC oven and are heated with a wire. When it is time to cool down, they cool down from the air in the room - and unbelievably fast. You can ramp these things up at a blistering rate as well. But if you break one of these columns - it has to be specially wrapped, so there is some operating cost to be considered. But if you get paid by the sample - this is a way to crank out more on a single instrument.

I find the best way to reduce cool down times and hence reduce the between injection time is to keep the starting temp as high as possible and the final temp as low as possible. This is a very low cost option!!!

GCguy