5.5
Unpacking a packed column
The following procedures may be used for both Intelligent Packing and manual packing.
Ensure that the pressure alarm is enabled in UNICORN.
Note:
WARNING
Remove the mechanical locking equipment before unpacking the
column. If it is not removed over-pressure may be created in the
column.
1
Replace the tubing from the top mobile phase inlet/outlet with a stop plug.
2
Relieve the pressure in the hydraulic chamber (see Handling over-pressure in the
column, on page 51).
3
Connect one end of a tubing to the hydraulic chamber outlet valve and the other
end of the tubing to waste.
4
Start the system with slow pumping (30 cm/h) upflow. Monitor the pressure constantly
to see that it does not increase above the maximum pressure rating for the column
and the medium, and check that hydraulic liquid is running to the waste container.
5
When a thin layer of liquid has accumulated under the packed bed increase the flow
rate successively, again monitoring the pressure carefully. During this procedure the
adapter will move upwards in the column and the medium bed will successively
break up.
NOTICE
Never exceed an adapter velocity of 120 cm/h, to avoid damage
to the scraper seal.
6
As the adapter begins to reach its upper position, slow the flow rate for the final 3-
4 cm.
7
When the lower surface of the adapter is about 2 cm below the lower surface of the
top bayonet, turn off the flow. This is to facilitate safe removal of the liquid above
the adapter.
8
Open the top plate, remove remaining hydraulic chamber liquid, close the top plate
and pump the adapter to its upper position. See Moving the adapter upwards in the
column, on page 46. A sudden pressure decrease indicates that the adapter has
passed the beveling at the top of the (glass) tube.
9
Remove the top plate and adapter (Removing the top plate and adapter, on page 49).
102
AxiChrom 50, 70 and 100 columns Operating instructions 28-9331-08 AG
5 Operation
5.5 Unpacking a packed column
