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Note: First, set the pressure to 3.0 MPa. Depending on the extent of filter clogging
and dimensional (internal diameter and length) variation in the tube
connected to the pump outlet port, the OVER PRESS message may appear
on the display. If this happens, increase the maximum pressure setting.
(3) Sufficiently degas the water to be used during replacement.
4.2.2 Replacing the solvent with water
First, replace the solvent up to the purge valve with water.
(1) Open the purge valve.
(2) Transfer the inlet tube from the container holding the buffer to a container
holding a small amount of water then start the pump immediately.
(3) Verify that the solvent is flowing out of the drain tube without interruption.
(4) While continuing to pump, lift the inlet tube out of the water, take in 3 ~ 5 ml of
air (bubble), and reinsert the inlet tube into the water.
Bubble
Figure 4.3 Bubble Uptake
Note: The inherent properties of water cause bubbles to remain in the tubing more
easily than is the case with organic solvents. In order to prevent bubbles
from remaining in the tubing, be sure to sufficiently degas the water before
using it to replace a solvent.
(5) The air bubble will be taken up into the pump and discharged from the drain
tube. Make sure that water continues to flow out of the drain tube without
interruption.
Note: If the solvent flow stops or if bubbles remain in the inlet tube, attach a
syringe to the drain tube and draw out the solvent (See Fig. 4.2).