| 摘要 |
A pumping arrangement for pumping a liquid product (10), such as oil products or liquefied gas, from a tank or container (11) comprises a rotary, high capacity main pump (12), such as a centrifugal pump, to be submerged in the liquid product. The main pump (12) is driven by an electric motor or another rotary driving motor (17) via a driving shaft (24). The driving motor (17) may be positioned above the upper liquid level. The pumping arrangement further comprises an auxiliary positive pump (29), such as a piston pump, for pumping a residual amount of said liquid product from the tank or container, and means (42, 43) for selectively drivingly interconnecting the auxiliary pump (29) to the driving shaft (24) of the main pump (12). Thus, the auxiliary pump may be driven by the same motor as the main pump. The means for selectively connecting the auxiliary pump to and disconnecting the auxiliary pump from the driving shaft of the main pump may comprise a ratchet device and may be activated by reversing the direction of rotation of the driving shaft.
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