The process of cross flow membrane filtration uses pressure to force liquid
across the surface of a porous membrane. The size distribution of the pores in
the membrane determines which components in the liquid pass through the
membrane and which ones will be retained.
There are a variety of
different membrane types and arrangements. Each type has particular
characteristics that make it suitable for a particular application.
Polymeric (or organic) membranes are available across the complete
spectrum of filtration types. There are some limitations to operating
temperature and pH, however special construction features have provided for the
release of temperature resistant and pH resistant membranes in the spiral
range.
The polymeric membrane types available include:
- spiral wound
- tubular
- hollow fibre
- plate and frame
Inorganic membranes are by nature tolerant to high temperature, extreme pH
and solvents. The rugged construction allows their use in extreme operating
conditions. The filtration spectrum is limited to Microfiltration and
Ultrafiltration for these membrane types – a variety of well defined pore sizes
are available.
The inorganic membrane types include: