| 摘要 |
<p>Method and apparatus for controlling the pressure differential across the filter membrane (14) in membrane plasma filtration apparatus (12). Control means (26) in fluid communication with a plasma-containing fluid flow path (30) up-stream of the filter membrane (14) and cooperatively associated with the plasma filtrate flow path (32), is operable to vary the size of the plasma filtrate flow path (32) inversely with respect to changes in the pressure in the plasma-containing fluid, thereby maintaining the differential pressure substantially constant. The control means includes a movable surface (34) disposed for contact with fluid in the fluid flow path (30) upstream of the membrane (14), the surface (34) being movable upon pressure changes in the blood flow path (30) to vary the size of the plasma filtrate flow path (32). The movable surface (34) is biased to a normally open plasma filtrate flow path condition by a force of selected amount corresponding to the desired pressure differential.</p> |
