单项选择题X 纠错
A.suppressant additive
B.dispersant additive
C.extreme pressure additive
D.viscosity improver additive
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单项选择题
A.centrifugal pumps
B.jet pumps
C.propeller pumps
D.reciprocating pumps
单项选择题
A.a compressed packing gland
B.lantern tings between the packing rings
C.a liquid seal
D.the stuffing box gland
单项选择题
A.loss of second stage vacuum
B.contamination of the distillate
C.lower feed inlet temperature
D.contamination of the second stage condenser
单项选择题
A.total head
B.discharge head
C.net positive suction head
D.suction head
单项选择题
A.slide block
B.tilting box
C.pintle
D.reaction ring
单项选择题
A.Liquids with different viscosities will always have the same specific gravity
B.Liquids with different viscosities will never have the same specific gravity
C.Viscosity and specific gravity are directly proportional
D.Viscosity and specific gravity are not related in that one does not define or limit the other
单项选择题
A.stored at temperatures below 60 degrees Fahrenheit
B.charged into a system having copper fittings
C.allowed to mix with compressor oil
D.exposed to an open flame or hot surface
单项选择题
A.acid formation
B.sludge formation
C.ice in the expansion valve
D.All of the above
单项选择题
A.superheated outside the system
B.in contact with an open flame
C.heated to the boiling point
D.All of the above
单项选择题
A.Variable volumes can be obtained with gear pumps only by variation of the pump drive speed
B.A radial piston pump houses sliding pistons in a stationary cylinder block through which passes a rotating pintle or ported shaft
C.The amount of fluid displaced per revolution of an axial piston rotary pump is dependent on the angle formed between the cylinder block and valve plate
D.All of the above