单项选择题
Which of the following statements represents the advantage of rotary pumps as compared to reciprocating pumps?（）
A.The high discharge pressure of the rotary pumps permits a larger volume of fluid per unit time than the reciprocating pump
B.Rotary pumps are capable of pumping more fluid than reciprocating pumps of the same weight
C.Rotary pumps occupy only one-half the space of reciprocating pumps
D.Rotary pumps eliminate discharge slippage of the pumped liquid, while this does not hold true for a reciprocating pump
相关考题
-
单项选择题
If a reciprocating air compressor has a knock occurring in frequency with its operating RPM, the cause is probably （）.
A.misalignment or worn main bearings
B.insufficient cylinder lubrication
C.defective or poorly fitted valves
D.all of the above -
单项选择题
Why are removable sleeves installed on centrifugal pump shafts?（）
A.They make it easier to replace the pump shaft packing
B.They can be economically replaced as they wear out
C.They can be removed when it is necessary to lighten the weight of the pump
D.They increase the strength of the shaft -
单项选择题
In reference to air conditioning, when air attains the maximum amount of moisture it can hold at a specific temperature, it is said to be （）.
A.superheated
B.saturated
C.condensed
D.convected
