单项选择题

Which of the following are components of a mechanical seal? （）
(1) stationary ring
(2) rotational ring
(3) packing
(4)spring

A.(1), (2) and (3)
B.(1), (2) and (4)
C.(2), (3) and (4)
D.None of the above

点击查看答案&解析

上一题目录下一题

单项选择题

A.variable stroke pumps
B.multistage pumps
C.positive displacement pumps
D.triple-ported pumps

单项选择题

A.mixed-flow pump
B.axial-flow pump
C.centrifugal pump
D.displacement pump

单项选择题

A.on top cover
B.on sides of bowl
C.in drain line on the discs
D.on the discs