Prime Water Membrane filters
Prime Water membrane filters consist of a bundle of hollow fiber membranes in a tube, where the space between the membranes and the tube has been hermetically sealed with an epoxy resin. A very efficient construction, as it does not leave unused space in the cartridge, which is the case in helically wound cartridges.
The low pressure drop across the membranes enables a very compact construction and high flow rates at point of use applications.
Prime Water offers two filtration techniques:
In the so called "Dead end" filtration technique (figure 1), the water flows from the outside to the inside and the filtered particles are caught in the porous membrane wall, which gradually clogs. A decrease in flow rate to an unacceptable level is a signal for replacement of the filter. This technique is applied mainly with micro-filtration membranes in the Legionella Safe Shower filters, In Line filters and Dual Stage filters.
In the so called "Forward flush" technique (figure 2), the water flows from the inside to the outside, retaining the filtered particles, as well as bacteria and viruses on the inside of the membrane. This technique allows reversing the flow and flushing of the membranes from the outside to the inside with filtered water, while disposing the dirt from the bottom of the cartridge.
Purification Standards
The Prime Water Membrane filters meet the highest purification standards, as for instance the US EPA standard and protocol for micro-biological water purifiers.
Service Life
As a result of the broad and unpredictable variations in the nature and concentration of micro-particles in the water, the service life of a "dead end" membrane filter will depend on local water conditions and the presence of pre-filtration.
The service life of a "dead end" membrane filter can be assessed by measuring the concentration of micro-particles by means of the SDI (Silt Density Index) method.
Click here for the results of the SDI test method.
Figure 1 - "Dead end" filtration
Figure 2 - "Forward flush" filtration
Figure 3 - Prime Water Membrane Filter
