Prewetting Procedures

UltiKleen™-CDS, Emflon® PF, Ultipleat P-Emflon® and Emflon® filter cartridges and assemblies require prewetting for the filtration of most acids and aqueous-based liquids in order to achieve good flow rates. Prewetting is not essential for solvents and liquids with surface tensions below approximately 30 dynes/cm2. Recommended procedures are as follows:

Emflon® PF Assembly

Figure A: In-Line Kleen-Change Assembly - Figure B: T-Type Kleen-Change Assembly
  • The KLEEN-CHANGE® assembly is configured as shown in Figures A or B (depending on the assembly style). The T-type KLEEN-CHANGE® assembly should be mounted bowl side up. This will allow for draining of the fluid from the assembly through the vents.
  • The assembly is flushed with 8 liters of IPA/water (60/40) at a flow of 1 GPM. The valves upstream and downstream of the assembly (V1 and V2) are open when flushing the IPA/water.
  • Terminate the flow of IPA/water and close V1 and V2 completely. Allow the assembly to stand in this fashion (filled with IPA/water) for 30 minutes.
  • The assembly is then drained of the IPA/water solution through the upstream vent (VU). For the T-type KLEEN-CHANGE® assembly the valve downstream (V2) of the assembly is opened.
  • To drain the in-line KLEEN-CHANGE® assembly of any remaining fluid, invert the assembly and drain the filter through the upstream vent (VU2) with the valve V2 open.
  • Open valves V1 and V2 and flush the assembly with 18 Megohm DI water at a flow of 1.5 GPM for 20 minutes. The in-line assembly must be inverted back to its original configuration before proceeding with this step.
  • The assembly is drained of the 18 Megohm DI water through the upstream vent (VU). For the T-type assembly, the valve downstream (V2) of the assembly is opened. To drain the in-line assembly of any remaining DI water, invert the assembly and drain the filter through the upstream vent (VU2) with the valve V2 open.
  • The assembly is now ready for installation in the equipment.
  • If an exothermic fluid is mixed with water (e.g. conc. H2SO4), it is strongly recommended that the assembly first be exposed to the dilute chemical prior to exposure to the concentrated chemical to avoid localized heating.

Note

Ensure that the assembly is vented correctly during the prewetting procedure. The presence of any trapped air in the assembly will cause the membrane to de-wet.

V1 and V2 should be all fluoropolymer diaphragm valves. The pump, tubing and piping (upstream of the filter) should also be all fluoropolymer materials.


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UltiKleen™-CDS, Emflon® PF, Ultipleat P-Emflon and Emflon

  • Place filter in a 2 liter graduated cylinder containing 1.5 liters of 60/40 isopropanol (IPA)/water.
  • Orient the filter so that the open end is facing up. Slowly immerse the filter cartridge into the solvent.
  • Allow filter to remain submerged for 30 minutes.
  • Remove filter, drain the excess, and re-submerge into 1.5 liters of 18 Megohm DI water for 5 minutes.
  • Remove filter, drain the excess, and install in a rinse-up filter housing.
  • Rinse-up for 20 minutes at 2 GPM/7.5 lpm (1 GPM/3.75 lpm for 5"/127 mm filter cartridge) using 18 Megohm DI water.

Note

Prewetting can be best accomplished by vacuum-drawing or pumping the 60/40 IPA/water prewetting solvent through the filter, followed by a 30-minute soak. This is especially recommended for the 0.05 µm filters, which are more difficult to wet due to tighter pores. If using concentrated acids with a high heat of mixing with water, it is strongly recommended that the filter be exposed to dilute acid (< 10%) prior to exposure with the concentrated acid. This prevents localized high temperature excursions from occurring.


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