Depth filter sheets are used to remove particles from liquids. This means that liquids can be clear, fine or sterilization-filtered. For depth filtration filter media of a thickness of 2.5 to 4.5 mm are required. The particles are retained using two filtration principles: 1. surface filtration and 2. depth filtration. The liquid flows through a three-dimensional, asymmetrical fiber network in the depth filter. The solid components are retained using mechanical and electrokinetic effects. This significantly increases the absorption capacity. The purpose of a filtration process is to produce either a liquid (filtrate) or solids (retentate). Depth filtration focuses mainly on the production of liquid filtrate.
Formats are available from 6 cm round to 2.425 x 1.215 m square. Practically every format in between is possible, which means they can be installed in any commercially available sheet filter. Depth filter sheets have a particle absorption capacity of up to 4 kg/m2. Furthermore, any FILTROX filter sheet grade is available in lenticular module format. PURAFIX® depth filter sheets have been specifically developed for the use in critical applications such as the processing of biopharmaceutical products. They are characterized by their extremely low levels of ions and pyrogens.