| 摘要 |
<p>The proposed drum pump has an outer pipe and a coaxial inner pipe which has a motor-driven drive shaft with a propeller. The propeller conveys the liquid from an intake port through an annular duct formed between the outer pipe and the inner pipe upwards to an outlet port. In the flow path of the liquid, behind the propeller, there is provided in the outer pipe a non-return valve which prevents back-flow or outflow of the liquid when the pump is switched off. Moreover, the propeller is provided directly next to the lower intake port, so that it is possible to strip even extremely small amounts of residual liquid.</p> |
