Alfa Laval - RO spiral

RO spiral

The reverse osmosis spiral membranes from Alfa Laval are based on a unique construction of either polyester or polypropylene support material in a sanitary full-fit design that provides optimum cleaning conditions. The spiral membranes are available with different reverse osmosis membrane types and in different combinations of length, diameter and feed spacer size

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Alfa Laval reverse osmosis spiral membranes use membranes with pores so minute that only small fractions of salts can pass through, along with the water that is the prime component of the permeate.

Certain organic compounds with low molecular weights can also pass - but only to a limited extent. However, it is impossible for any other components suspended or dissolved within the liquid flow (salts, sugars, etc.) to do so.

Alfa Laval reverse osmosis spiral membranes are used for the concentration of many feed streams particularly of heat sensitive products, pre-concentration prior to evaporation as well as product and water recovery from permeate streams and evaporator condensate. 

Alfa Laval offers two series of reverse osmosis spiral membranes with different NaCl rejection properties. The membrane materials are thinfilm composite cast on either polyester or polypropylene backing paper.

RO PE Series

The spiral membranes of this series are the types RO99 and RO90 having a NaCl rejection of 98% and  90% respectively.

RO98pHt Series

In this series you find the RO98pHt spiral membrane which is characterized by its high temperature tolerance compared to the RO PE series. The RO98pHt spiral membrane has a NaCl rejection of 98%.

Benefits

  • cost-effective operation due to low energy consumption
  • cover a broad range of salt permeabilities
  • available in different combinations of length, diameter and spacer size
  • sanitary design with all materials in compliance with EU regulation (EC) 1935/2004, EU Regulation 10/2011 and FDA regulation (CFR) Title 21. USDA approved
  • same membrane types available as both flat sheet membranes and spiral membranes
  • suitable for extensive range of processes
  • suitable for processing at low temperature
  • manufactured by Alfa Laval's own membrane centre

Fonctionnement

La technologie de base de la filtration membranaire consiste à utiliser une membrane semi-perméable pour séparer un liquide en deux flux distincts.

Le pompage de ce liquide à la surface de la membrane crée une pression transmembranaire positive qui permet le passage de tout composant plus petit que la porosité de la membrane, formant ainsi le perméat.

Tous les composants plus grands que la taille des pores ne peuvent tout simplement pas passer, et restent derrière dans ce que l'on appelle le rétentat. La surface de la membrane est maintenue exempte de blocages par la force du débit du liquide qui s'écoule parallèlement à la surface de la membrane.

Une membrane à spirale se compose d'un certain nombre d'enveloppes de membrane avec 2 feuilles de membrane séparées par une maille d'espacement pour perméat, chacune collée à un tube collecteur central de perméat.

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Entre chaque paire d'enveloppes se trouve un espaceur qui crée le canal d'alimentation, permettant à l'alimentation de s'écouler sur toute la longueur de la membrane à spirale, tandis que le perméat passant à travers la membrane, dans son enveloppe, s'écoule à spirale vers le tube collecteur de perméat.

Rouge = Alimentation/rétentat.

Jaune = Perméat.