99色精品-9色在线-99色在线-99色视频国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

<abbr id="5ajjv"><output id="5ajjv"><ruby id="5ajjv"></ruby></output></abbr>

單項(xiàng)選擇題

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

你可能感興趣的試題

單項(xiàng)選擇題

In a （） the center screw is driven and the outer screws idle.

A.single screw pump
B.double-screw pump
C.triple screw pump
D.centripetal pump

單項(xiàng)選擇題

The discharge flow of a reciprocating pump is （）.

A.steady
B.in pulsation
C.continuous
D.large

<ins id="tmxgj"></ins>

<ruby id="tmxgj"><output id="tmxgj"></output></ruby>