Chromatography Forum

Hi all

I have a 6890 GC inlet that is very poorly insulated arround the inlet and need to beef it up. It is unable to hold its temp mainly when the oven fan is blowing (It has a packed insulation cup in there that doesn't help much).

What kind of insulation can I use and where can I get it?

In a pinch I have used just plain glass wool. It isn't the really dense stuff the comes with the instrument but will help.

You can get ceramic wool in sheets or fluff from RS components, like this http://uk.rs-online.com/web/p/thermal-i ... s/7248921/ but my guess would be that there is something wrong with the inlet heaters if it cannot hold temperature.

Peter

Hi,

I've run into the same problem. If there's a piece of the insulation missing from the inlet itself, it may have difficulty reaching over 300 degrees C.

Agilent's website has some part numbers for both the PTV & purged/packed inlet insulation block, for both 7890s and 6890s, but I didn't find one for the SSI.

http://www.agilent.com/store/en_US/LCat ... 901/Inlets

They also show parts for the cup insulation, which I've used by tearing apart and jamming it in where the missing insulation block is.

That solved the issue for me both times, and I was heating my inlet to 400C. Really important to have consistent insulation around the inlet to maintain a stable temperature.

Hope this helps.

It just doesn't seem to have much insulation at the very top and bottom. At the top I can look through the holes of the weldment top and see empty space for a few centimeters down and also at the bottom above the insulation cup. I also can put my hand above the inlet and feel heat just radiate everywhere and the needle guide for the ALS is very hot as well. It can maintain 250 only with the oven fan off.

I was wondering if oven insulation from an appliance store would work or if the GC is to hot for that. Otherwise I have a big old container of glass wool I can just pack it below the top of the weldment and above the side near the gold seal above the cup.

I once had to cut out the insulation over top of the oven on an Agilent GC. I stuffed fiberglass tape into the void, from one of the big scientific suppliers.

How about some exhaust insulation tape from an auto store? https://www.google.com/search?q=exhaust ... ation+wrap

That sort of tape though is meant to wrap around a pipe or tube. I am looking to fill a void. I think plain old glass wool so far sounds like the best bet.

It just doesn't seem to have much insulation at the very top and bottom. At the top I can look through the holes of the weldment top and see empty space for a few centimeters down and also at the bottom above the insulation cup. I also can put my hand above the inlet and feel heat just radiate everywhere and the needle guide for the ALS is very hot as well. It can maintain 250 only with the oven fan off.

I was wondering if oven insulation from an appliance store would work or if the GC is to hot for that. Otherwise I have a big old container of glass wool I can just pack it below the top of the weldment and above the side near the gold seal above the cup.

Definitely some insulation missing if you can see down from the top like that. there is normally a flat pad of insulation that sits against the perforations at the top of the weldment before the heater block slides on. Not sure why that isn't showing up on the Agilent site as a replacement part, surely they don't want you to purchase the whole weldment just because that insulation crumbles.

surely they don't want you to purchase the whole weldment just because that insulation crumbles.

I think you have a "don't" too much in that sentence.

I like to use glass wool in a pinch. It is easier to snug some wool in to the visible gaps than it is to remove the inlet again.