Both systems operating in cross-flow mode are shown in Fig. 2. The
permeate flux at the start of the batchwisefiltration of vat milk with 3.2%
fat running via the MF pilot plant was 81.5 L/hm² at a transmembrane
pressure of 1.1 bar and a feed inlet pressure of 4.35 bar. The viscosity of
the retentate rose as the concentration of the vat milk increased. To
maintain a pumpable consistency of the highly concentrated retentate,
the temperature was raised from DM 14% to 58 °C and from DM 27% to
75 °C until the end of filtration. With increasing concentration of the vat
milk, the transmembrane pressure rose to 3 bar until a minimum
permeate flux of approx. 12 L/hm2 was achieved and filtration could be
completed.