| 摘要 |
An apparatus for separating from a biological liquid, in particular blood, a fraction having molecular weight between an upper and a lower limiting value, comprises a liquid container (B1) for the separated fraction and included in a closed circulation circuit (I2) between a first and a second molecule filter (F1, F2) each with a flow driving pump (P1, P2). A control system is provided for controlling the liquid volume V in the container in accordance with the equation: dV/dt = Qa + Qb, in which V is the regulated liquid volume, the desired value of which is stored as predetermined time function V(t) in the memory (H) of the control system, and Qa and Qb are the total liquid flows into and out of the closed circulation circuit, respectively. Blood from a patient under treatment is supplied to the first molecule filter (F1), and the liquid filtrate which is discharged from the output side of the second molecule filter (F2), is fed back to the blood flow system (M) of the patient. The predetermined time function V(t) is defined in such a way that the separated liquid volume is automatically adjusted in agreement with prior experience and adapted to the particular patient under treatment. A third filter (F3) may be disposed in the feed back conduit to the patient in order to extract liquid from the returned filtrate and thus increase the protein concentration in this filtrate, the extracted liquid being returned to the container (B1) in the closed circulation circuit. In cooperation with a protein detector (PD) the filter (F3) may then serve as a controller of the protein concentration in the fed back filtrate. |
