| 摘要 |
In a plasma apheresis or renal dialysis unit the blood is pumped by a mechanism having a flexible conduit 30 in which are located non-return valves 31. A linear actuator 33 periodically compresses a part of the tube between the valves under the control of a microprocessor. As described, a stepping motor 38 drives screw a 36 mounted in block 37 to reciprocate head 33 between guides 39 at a pulse rate of 3.33-0.833 Hz to give a volume displacement of 0.25-4 ml per stroke. A pressure sensor is described comprising a C- shaped resin clip, adapted to surround the conduit, and in which is embedded a wire acting as a strain gauge whose resistance is monitored to determine pressure. |
