The table provides information about the piston seals used in the pumps and their solvent compatibility.

Pump

Piston Seals

VC‑pumps except VC‑P21 and VC‑P33

The pumps are shipped with UHMW-PE piston seals. Using tetrahydrofuran, ketones, or ammonium hydroxide as solvents can damage the seals.

In rare cases, a shortened lifetime of reversed-phase (UHMW-PE) piston seals has been observed with high pH, ammonium hydroxide containing mobile phases and prolonged exposure.

Under harsh conditions, consider replacing the UHMW-PE piston seals with carbon-fiber filled PTFE piston seals. Consider the following:

  • With the piston seals, also replace the seal wash seals (part no. 6040.0306, containing 2 seals for use as both, piston seal and seal wash seal).

  • Install new pistons. Exchanging the piston seals but keeping the pistons that were used with the UHMW-PE piston seals may impair the seal life of the PTFE seals.

  • Note that slightly increased abrasion may be observed with these seals, depending on the application. Consider testing the permeability of the static mixer regularly at short intervals.

VC‑P21 and VC‑P33 pumps

The pumps are shipped with carbon-fiber filled PTFE piston seals. Slightly increased abrasion may be observed with these seals, depending on the application. Consider testing the permeability of the static mixer regularly at short intervals.

VF‑pumps

The pumps are shipped with UHMW-PE piston seals. Using tetrahydrofuran, ketones, or ammonium hydroxide as solvents can damage the seals.

In rare cases, a shortened lifetime of reversed-phase (UHMW-PE) piston seals has been observed with high pH, ammonium hydroxide containing mobile phases and prolonged exposure.

Under harsh conditions, consider replacing the UHMW-PE piston seals with carbon-fiber filled PTFE piston seals. Consider the following:

  • With the piston seals, also replace the seal wash seals (part no. 6040.0306, containing 2 seals for use as both, piston seal and seal wash seal).

  • Install new pistons. Exchanging the piston seals but keeping the pistons that were used with the UHMW-PE piston seals may impair the seal life of the PTFE seals.

  • In addition, note the following:

    • Slightly increased abrasion may be observed with the PTFE seals, depending on the application. Consider testing the permeability of the static mixer regularly at short intervals.

    • The pump should not be operated with pressures higher than 70 MPa.

    • The pump is no longer biocompatible.