A.Protects against suction valve float
B.Provides a positive pressure on the air inlet valves
C.Prevents lubricating oil contamination of the compressed air supply
D.Protects against the damaging effects of airborne solid particles
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A.warm-up allows the hydraulic system to become charged with oil
B.warm-up allows the relief valves to be properly tested
C.hydraulic strainers operate only during the warm-up period
D.hydraulic fluid must be at the proper viscosity
A.are exposed to a vacuum
B.come in contact with extremely hot surfaces
C.are reduced in temperature to just above the pour point
D.become extremely agitated or aerated
A.weight
B.internal friction
C.demulsibility
A.Extensive centrifuging
B.Wax content
C.Water content
D.Acid content
A.Viscosity will increase as temperature increases
B.Viscosity is a measure of a fluid s internal resistance to flow
C.Viscosity will decrease as temperature decreases
D.Viscosity is not dependent on temperature
A.the manual trick wheel is engaged for steering
B.the variable stroke pump is off stroke
C.a rudder order is given by the control system
D.an electric power system failure occurs at the steering gear
A.cool the expansion valve
B.prevent refrigerant superheating
C.condense the refrigerant gas
D.prevent motor overheating
A.Closing of the solenoid valve
B.Closing of the expansion valve
C.An increase in the suction pressure
D.Decreasing the suction pressure
A.When the helm is at any angle other than amidships
B.When the six-way valve is opened
C.When the ram relief valves lift
D.When the redder angle is different from the position of the helm
A.suppressant additive
B.dispersant additive
C.extreme pressure additive
D.viscosity improver additive
最新试题
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by ().
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its ().
The control mode in which the final control element is moved from one of two flexed positions to the other is known as ().
The general purpose of a heat exchanger is to ().
A salinity indicator is used to determine the ().
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?()
Which of the following statements is correct concerning heat transfer?()
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will ().
The major source of chemical contaminants in hydraulic fluid is ().
The output volume of a positive fixed displacement pump can be changed only by ().