When

When new piston seals have been installed

TIP

The actions recommended in this section directly influence pump performance and the piston seal life cycle.

Items required

  • Backpressure capillary (length: 15 m) and Viper union (from the Diagnostics tool kit)

  • nanoViper™ capillary (length: 750 mm, inner diameter: 75 µm)

  • Silicone tubing

  • Isopropanol

  • Solvent suitable for your application

Recommendations

  • Allow new piston seals to run in.

  • Never run the pump dry.

    Running the pump dry can damage the pistons or piston seals.

Allowing New Piston Seals to Run In

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

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

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

  4. Install the backpressure capillary on the pump outlet.

  5. With the Viper union, connect the nanoViper capillary to the backpressure capillary. Guide the free end of the capillary to the waste container.

  6. Operate the pump. For 15 minutes, apply a flow of 1.3 mL/min using isopropanol.

  7. Close the purge valve by turning the valve knob clockwise.

  1. Generate the necessary backpressure. For 30 minutes, apply the flow indicated in the table using isopropanol.

Pump Type

Flow

Backpressure

VC-pumps

1 mL/min (approximately)

45 MPa (approximately)

VF-pumps

2 mL/min (approximately)

80 MPa (approximately)

  1. Turn off the pump flow and wait until the system pressure is down to zero.

  2. Remove the capillary from the pump outlet and reconnect the pump to the system.

  3. Purge the pump using the solvent for your application.

  4. When purging is complete, empty the silicon tubing.

  5. If an increased leakage rate is observed with new piston seals after several hours of operation, operate the pump for at least 2 hours at 35 MPa.

TIP

If the piston seals are not sufficiently tight yet, have the pump build up high pressure and hold the pressure for some minutes.

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.