Comparison of cross flow filtration and dynamic shear stress filtration–an analysis of design features and performances

摘要

Micro and Ultra filtration are separation processes producing absolute particle-free and even sterilised filtrates. High cross flow velocities tangentially to the membrane surface prevent a permanent particle deposition and, thus, a clogging of the fine membrane pores and a high transmembrane flux, respectively. Besides the classical Cross Flow Filtration with capillar-, tube- or flat chamber modules, the much more effective Dynamic Shear Stress Filtration could find its own position within the process technology and on the market. With this process realised in the DYNO Filter the tangential flow over the filter medium which is typical for the cross flow filtration is - in contrast to classical cross flow filters - not generated by pumps but by rotors which generate a turbulent cross flow of the suspension over the filter medium. With the DYNO Filter suspensions with critical separation characteristics like high viscosity, intrinsic viscous or thixotrope characteristics can be thickened, washed, clarified or classified with the dynamic high shear filtration in a continuous operation with permanently high throughput rates. rnThe new process of dynamic sieve filtration offers the possibility that highly concentrated and highly viscous suspensions can be sieved for the first time in a hermetically sealed filter with excellent selectivity and with continuously high throughput rates. rnThe latest process development is the application of the dynamic cross flow filtration for the separation of suspensions with nano-particles. For this demanding future-oriented filtration task the DYNO Filter is excellently suited.