| 摘要 |
<p>A drive mechanism (20) for delivery of infusion medium including an electrically coil (38). The coil (38) surrounds a piston channel (35) extending in an axial direction. The piston channel (35) provides a passage for communication of infusion medium to an outlet chamber located at one end of the piston channel (35). A piston (44) is located within the piston channel (35) and is moveable axially within the channel (35) to a forward position, in response to movement of an armature (42) to its forward position. The armature (42) and piston (44) are moved toward retracted position, when the coil (38) is not energized. In the retracted position of the piston (44), a piston chamber (65) is formed. As the piston (44) is moved to its forward position, the piston chamber (65) volume is reduced and pressure increased to move a valve member (66) into an open position.</p> |
