| 摘要 |
1517874 Centrifuge for separating blood UNITED STATES ENERGY RESEARCH & DEVELOPMENT ADMINISTRATION 26 March 1976 [25 April 1975] 12183/76 Heading B2P In a method of operating a continuous flow centrifuge for separating whole blood into red cells, white cells and plasma the hematocrit (i.e. the ratio of the total volume of red cells, white cells and platelets in blood to the total blood volume) of the whole blood fed to the centrifuge is continuously measured and is maintained at a selected value. The centrifuge, which may be of the type described in Specification 1506807, has a rotor equipped with a feed line for whole blood, extraction lines for the red cell, white cell and plasma fractions respectively and a recycle line connecting the plasma extraction line to the feed line, variable speed pumps being located in the feed, plasma and recycle lines. The electrical conductivities of the entrant whole blood and the plasma are measured by conductivity probes disposed in their respective lines and compared by means of a differential comparator to provide a signal to control the variable speed plasma recycle pump enabling the feed hematocrit to be maintained at the selected value. Alternatively, the feed hematocrit is maintained at the selected value by continuously adding red cell-rich plasma from the red cell extraction line to the feed line. In addition, the method of operation may include the further step of measuring the electrical conductivity of the red blood fraction and comparing it with that of the plasma fraction to produce a signal to control the speed of the feed pump and hence the feed rate of the whole blood to maintain the hematocrit of the extracted red cell fraction at a selected value. A diagram of the controlling circuit is given. |
