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Melissa,
There is most likely a problem with the pneumatic valve inside the Conflo
interface. I would assume a blockage in the "dilution on" split section. If
you remove the cover from the Conflo you will see a small pneumatic valve on
the right. The Ea flow from the back of the interface connects to this
valve. This valve switches from a split of the EA flow from 72ml/min with
dilution off to 79.5ml/min with dilution on (flow rates based on 80ml/min EA
flow; as in conflo manual pg 2-3). It does this by switching flow paths, one
path being more restricted than the other.
It would appear that the "dilution on" flow path is clogged and creates a
back pressure on the EA slowing flow. I would suggest disassembly of the
valve and both flow paths and cleaning both thoroughly with acetone followed
by MeOH. Dry parts well in a oven at ~30C. I would also suggest replacement
(or at very least cleaning as above) of the glass capillary associated with
the EA flow to the open split. While it is open, you may want to clean the
open split glass as well, but it can be a pain to remove and reset all
capillaries. Noticeable brown stains in the open split would suggest a need
to perform this extra work.
Good Luck!
Cheers,
BJones

On Fri, Mar 28, 2008 at 12:10 AM, Melissa Bautista <
[log in to unmask]> wrote:

> Dear Isogeochemists,
>
> This is in regards to a change in carrier flow rate from our Flash EA 1112
> to a Conflo III.
> The carrier flow is set at 100ml/min. However, when the He dilution
> capillary is dropped in, the flow rate drops to c. 58ml/min. I have
> checked
> the heights of the capillaries in the open split and they are positioned
> correctly according to the manual. Can anyone tell me why this happens?
>
> Thank you
>
> Melissa Bautista
> Southern Cross University
> Lismore NSW Australia
>



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