| 摘要 |
<p>The pressure chamber (24) is closed off on the side furthest from seat (16) by the re-set piston (28) of the pressure rod (40). The re-set piston diameter exceeds the area of the seat (16) and the area comprising the difference between the sectional area of the piston (28) and the area covered by the seat (16) is smaller than the sectional area of the pressure rod. The re-set piston consists of an inner piston (32) and an outer piston (30) which seat onto a safety ring (38) on the injection needle (12). A return spring (34) in the pressure space (24) bears on the re-set piston. The valve (46) is controllably opened and closed by an included piezo-actuator (48).</p> |
