Membrane filtration for
Alfa Laval is one of the world’s major suppliers of industrial separation technologies. We have a proud tradition of providing virtually all industries with separation equipment based on centrifugal and mechanical principles.
However, there are many processes in which the substances involved are too delicate to be able to withstand such treatment.
The gentle alternative
Membrane filtration separates out the different components in a feed stream on the basis of the size and shape of the micro-particles within it. And the better the filtration, the better the quality and value of your end product.
This separation takes place by pumping the feed stream across the surface of a membrane with pores so microscopic that they are
measured in angstroms (1 x 10-10 m). Some components pass through – others cannot.
Membrane filtration is often used to supplement conventional centrifugal separation processes based on gravity differences. Membrane filtration can also be used for concentration prior to evaporation and spray drying.
Schematic cross-section of a thin-film membrane used in reverse osmosis Thin-film membrane layer Support paper Polyester (PE) or
The Alfa Laval take on membrane filtration
Alfa Laval is the world’s leading supplier of filtration membranes for sanitary use.
High-hygiene Alfa Laval membranes are the preferred choice for many leading users of membrane filtration technology, as well as for OEM suppliers of membrane filtration modules and systems.
Alfa Laval is unique in mastering the full spectrum of membrane filtration know-how. In addition to manufacturing and supplying membranes, we are also responsible for developing and designing these technically advanced products.
As a result, we are in a position to apply unparalleled end-to-end quality assurance procedures that greatly benefit every membrane user.
Selecting the right type of sanitary membrane, with the most appropriate configuration and specifications, is essential for making filtration processes as effective as possible in terms of hygiene levels, operating costs and yield. Meeting high-hygiene requirements Membrane filtration is becoming increasingly popular in high-hygiene processes that include:• Concentration and purification • Clarification and fractionation • Extraction • Product recycling and recovery • Product and effluent upgrading.
How membrane filtration works
The basic technology behind membrane filtration involves using a semi-permeable membrane to separate a liquid into two distinct streams.
Pumping this liquid across the surface of the membrane creates a positive trans-membrane pressure that forces any components smaller than the porosity of the membrane to pass through, forming the permeate. Any components larger than the pore size simply cannot pass through, and remain behind in what is called the retentate.
The surface of the membrane is kept free of blockages by the force of the liquid flow moving parallel to the membrane surface.
Alfa Laval manufactures membranes for use in an extensive range of processes used in the food, beverage, dairy, biotech and pharmaceutical industries. All Alfa Laval membranes – in both spiral-wound and flat-sheet designs and configurations – are therefore made to comply with the relevant FDA regulations.
This compliance also extends to the equipment and fittings related to membrane filtration operations, including items such as plate-andframe units, element housings and pumps.