| 摘要 |
The pump has an outer tube which surrounds an inner tube at a distance, forming an annulus. A pump shaft is mounted in this so that it can turn, and bears a rotor on its lower end. This is located in the vicinity of an intake that can be closed by a valve body. The latter is formed by a sphere that is moved into a position blocking the intake by its own weight or by a spring. The ball presents problems in use and does not ensure reliably that the intake will be sealed perfectly. In addition, the ball hinders pumping. Therefore, this pump is to be designed so that the valve body closes the intake reliably without interfering with pumping. The intake is closed by the valve body by means of a relative displacement between the outer and inner tubes. The valve body is thus forced into its closed or open position, so that the intake is closed reliably. Pumping is not impaired by the valve body, because this no longer has a tendency to move into the closed position if the pumping pressure drops. The pump is used for aspirating liquids.
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