The Pall Ultipleat SP DR filter, specifically designed for critical surface preparation (SP) chemical bath filtration, has a dual-retention (DR) capability. The SP DR filter features a new, highly asymmetrical membrane construction, developed using Pall’s proprietary membrane modeling technology (MMT).

The pore size distribution of the membrane uniformly transitions from microporous to nanoporous throughout its depth. The result is a new, application-specific membrane morphology designed for deep submicron retention of particles below 30 nanometers, without the flow restriction limitations of conventional membrane pore structures.

The final metered pore zone is expanded to create a multilayer matrix of selectively sized pores. This metered pore zone provides positive mechanical retention of particles that are the rated size and larger. The pore matrix can also capture smaller nanoscale particles through nonsieving mechanisms that are not pH-dependent. The integration of both sieving and nonsieving retention in the metered pore zone provides a dual-retention capability for consistent performance across a wide range of operating conditions.

The membrane material is a specially engineered, high-temperature-tolerant polymer with exceptional performance properties. These include hydrolytic and thermal stability, durability, and enhanced chemical resistance.
• MMT-enhanced dual retention of particles
• Superior HF filtration
• High flow rates
• Hyperfine microporous membrane matrix
• Hydrophilic membrane with no prewetting requirement
• Hydrophilic membrane for minimized microbubble formation
• Faster tool qualification for reduced cost of ownership
• Low extractables (typically <30 ppb total at start-up for 16 metals
   in a 5% HCl extraction of 1.5 L for 24 hours)
• 100% integrity tested
• Ultralow metal Me-Kleen^SM option