单项选择题
A.variable stroke pumps B.multistage pumps C.positive displacement pumps D.triple-ported pumps
Through a （） pump, the liquid is transferred from the s...
单项选择题Through a （） pump, the liquid is transferred from the suction to the discharge by the mechanical variation of the volume of a chamber or chambers.
A.positive displacement B.ejector C.centrifugal D.air compressor
A vane pump belongs to （） according to its working prin...
单项选择题A vane pump belongs to （） according to its working principle.
A.reciprocating pump B.positive displacement pump C.centrifugal pump D.centripetal pump
