• To remove air bubbles that might be trapped in the system (pump head, solvent lines) because air bubbles in the system may lead to the following problems:

    • Pressure pulsation

    • High noise level or pulsation during pump operation

    • Non-reproducible analysis

  • When changing to a different type of solvent, for example, when changing to a different analytical method

TIP

When the pump is operated for the first time or when solvent lines are empty, follow the steps in Purging with First Time Operation or Empty Solvent Lines.

Items required

  • Solvents suitable for purging

  • Silicone tubing

  • Tissue

Preparations

  1. To be able to generate negative pressure, connect an autosampler or another type of flow restriction to the pump outlet. If necessary, close the pump outlet with a fitting plug.

  2. On the purge/sensor unit, attach silicone tubing to the purge outlet (if it is not yet connected).

  1. Route the free end of the tubing to the drain port outlet (see Guiding Liquids to Waste).

  2. Open the purge valve by turning the valve knob counterclockwise.

Follow these steps

  1. In the Chromeleon software, set the channel that you want to purge to 100%.

  2. Optional: In the Chromeleon software, adapt the settings for the purge flow or purge time if required.

  1. Binary pump and dual pump: For purging from the keypad, verify that you have selected the pump head (pump) for which you want to perform the procedure.

  1. Start the purge cycle. You can start the purge cycle from the Chromeleon software or by pressing the PURGE button on the keypad.

  1. Perform the above steps for all channels, including those that are not used for the application.

  1. When purging is complete, close the purge valve by turning the valve knob clockwise.

NOTICE

Turn the valve knob only with your fingers. If the knob leaks, tighten a little more. Be careful; overtightening may damage the purge valve seals.

  1. Empty the silicone tubing.

  2. Dual pump only: If applicable, perform the purge procedure also for the other pump.

Emptying the Silicone Tubing

NOTICE

Always empty the silicone tubing when purging is complete. When the purge valve is closed, purge liquid remains in the tubing connected to the purge outlet. Leaving the liquid in the tubing for a longer period limits the tubing lifetime.

  1. To absorb any liquid that might be leaving the purge outlet when the tubing is removed, place the tissue under the outlet.

  2. On the purge/sensor unit, remove the silicone tubing from the purge outlet. The other end of the tubing remains in the purge drain port outlet.

  3. Hold the tubing so that any liquid that is present in the tubing flows off through the drain port outlet.

  4. On the purge/sensor unit, consider reconnecting the silicone tubing.

Troubleshooting with Persistent Air Bubbles

If you are unable to remove air bubbles with purging, purge the pump against backpressure. Follow the procedure for running in new piston seals in Recommendations for New Piston Seals.