11. Its lubricity is poor, so positive-displacement pumps are unsuitable and centrifugal pumps have to be used. 12. "' Endless-piston principle "'is a dispensing variation of rotating positive displacement pumps . 13. Some positive displacement pumps use an expanding cavity on the suction side and a decreasing cavity on the discharge side. 14. These positive displacement pumps have an expanding cavity on the suction side and a decreasing cavity on the discharge side. 15. Many variations of the positive displacement pump have been developed, and many other pump designs rely on fundamentally different principles. 16. :Is the OP asking about the advantages of axial flow pumps over reciprocating positive displacement pumps for purposes of propulsion? 17. Momentum transfer pumps in conjunction with one or two positive displacement pumps are the most common configuration used to achieve high vacuums. 18. This is the principle behind a "'positive displacement pump "', for example the manual water pump. 19. An "'Inductive pump "'is a magnetically regulated positive displacement pump used to pump liquids and gases. 20. A "'variable displacement pump "'is a device that converts mechanical energy to hydraulic ( fluid ) energy.
