Polymer offers single solution for filtration

When Alfa Laval of Denmark, a leader in filtration technology, wanted a material for the plate and frame modules of its crossflow membrane filtration systems, it chose unfilled Victrex Peek.

When Alfa Laval of Denmark, a leader in filtration technology, wanted a material for the plate and frame modules of its crossflow membrane filtration systems, it chose unfilled Victrex Peek.

This high-performance polymer combines the ease of thermoplastic processing with all the required properties to offer a single solution for the vast majority of filtration applications.

Available in three different heights for different viscosities, the Victrex Peek plate and frame modules are equipped with built-in membranes of appropriate porosity for the desired filtration process.

Membrane filtration is a physical separation process in which the driving force is the difference in pressure between the two sides of a special membrane.

According to Andrew Ragan, Product Manager, Victrex USA: "The need to separate smaller and smaller particles from each other within a flow stream is becoming more and more important in all process industries".

"Today, almost all industrial membrane filtration is carried out as crossflow filtration where the liquid being filtered flows parallel to the membrane at high velocity and under pressure".

Mechanical strength and stiffness were a major reason for choosing Victrex Peek.

"These properties enable high filtration efficiency that increases with rising process pressure", explains Ragan.

"Also important was the ability of Victrex Peek to withstand high pressures at elevated temperatures".

"As a semicrystalline polymer, the polymer has a glass transition temperature of 143C and a melting point of 340C".

"The superior chemical resistance of Victrex Peek was particularly important in this application", adds Ragan.

"The plate and frame components were previously made with polyethersulphone (PES) which sometimes suffered from environmental stress cracking when in contact with concentrated fruit juices".

"Unfilled Victrex Peek is FDA approved for food contact and can be used in filtration applications".

The Victrex Peek plate and frame modules can withstand numerous cleaning and sterilisation cycles without any significant change in performance.

They are approved for sanitary operation and offer significant advantages when product purity is paramount.

Depending on the type of membrane used, the crossflow filtration system can be employed for any separation task ranging from reverse osmosis where water is the only material that can permeate the membrane to microfiltration where suspended solids, bacteria and fat globules are the only substances not allowed to pass through.

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