A Magnetic Fluid-Driven Artificial Heart

各种植入式人工心脏已被研究。然而，它们都有一个共同的缺点，即使用轴承和复杂的驱动机构。另一方面，磁流体执行器直接通过施加磁场来驱动磁流体，而不需要轴承。研究了磁流体驱动人工心脏的可行性。两个气隙为10毫米的环形螺线管被安排在丙烯酸管（10 mmOD, 7.4 mmID）附近。一个小气球（体积：2mL）连接在丙烯酸管的两端。气球被包裹在一个坚硬的盒子里，盒子里有入口和出口。丙烯酸管和气球都充满了氟惰性物质。将磁性流体和一个铁圆筒浸入氟惰性液体中。两个螺线管根据计算机发出的控制信号交替激活。进行了两个实验：(1)单独使用磁流体。(2)磁流体与铁缸结合使用。这种组合被用作高磁化的磁流体的替代品。单独使用磁流体时，在140次/分钟下可获得26 mL/min的流量。闭合压为13mmhg。使用磁流体和铁筒，在260次/min下获得318 mL/min的流量。闭合压力为300 mmHg。采用磁流体配合铁缸，可获得90%的最大流量。计算表明，使用磁化强度为113千卡/米的磁流体可获得超过100毫米汞柱的驱动压力。如果研制出磁化强度为113 kA/m的磁流体，磁流体驱动的人工心脏是可行的。

A variety of implantable artificial hearts have been studied. They, however, have a common drawback of utilizing bearings and a complicated driving mechanism. A magnetic fluid actuator, on the other hand, drives magnetic fluids directly simply by applying magnetic field and does not require a bearing. Feasibility of a magnetic fluid-driven artificial heart was studied.Two ring solenoids with an air gap of 10 mm were arranged near an acrylic tube (10 mmOD, 7.4 mmID). A small balloon (volume: 2mL) was connected to the both ends of the acrylic tube. The balloon was encased in a rigid box that had an inlet and outlet port. The acrylic tube and the balloons were filled with Fluorinert. Magnetic fluid and an iron cylinder were immersed in Fluorinert. Two solenoids were alternately activated according to control signals from a computer. Two experiments were conducted: (1) magnetic fluids alone were used. (2) A combination of magnetic fluids and the iron cylinder was used. This combination was used as a substitute for magnetic fluids with high magnetization.With the use of magnetic fluids alone, a flow of 26 mL/min was obtained at 140 beats/min. Closing pressure was 13 mmHg. With the use of magnetic fluids and the iron cylinder, a flow of 318 mL/min was obtained at 260 beats/min. Closing pressure of 300 mmHg was obtained.With the use of magnetic fluids and the iron cylinder, 90 % flow of the maximum flow was obtained. Calculation disclosed that a driving pressure over 100 mmHg is obtained with the use of magnetic fluids with a magnetization of 113 kA/m.A magnetic fluid-driven artificial heart could be feasible if magnetic fluids with a magnetization of 113 kA/m are developed.