A spiral wrap element consists of several layers of flat membranes, spacers and drainage fleeces (permeate carriers), which are rolled up in a spiral to form a wrap (Fig. 1). In the center of the element is the permeate collecting tube, which leads the permeate taken out through the front of the module housing. The sealing is done by an adapter which is equipped with O-rings.
The active separating layer of the asymmetrical semipermeable membrane is located on both sides of the spacer (also called spacer) and is characterized by high mechanical strength and robustness.
The spiral winding element essentially consists of the membrane module, which is inserted in a housing. This can be PVC or Stainless steel.
In order to prevent individual layers of the membrane or spacer from telescoping due to the constant overflow of the module, so-called ATD’s (Anti Telescope Devices) are also inserted into the housing.