更多"External and internal leakage in hy"的相关试题:
[单项选择]Increased internal leakage, in addition to poor hydraulic system response,and inadequate lubrication, is the result of （）.
A. pump bearings in poor condition
B. excessively worn actuator-piston packing
C. broken directional control valve centering springs
D. low hydraulic oil viscosity
[单项选择]Leakage of hydraulic fluid from around the shaft of a hydraulic motor may be caused by（）
A. permanent loss of pump suction
B. worn shaft seals
C. high level in the oil sump
D. low motor RPM
[单项选择]Strainers are commonly used in hydraulic systems to （）.
A. protect the pump from fine soluble contaminants
B. prevent solid particles from entering the pump
C. prevent solid particles from entering the filter
D. protect the directional control valves
[单项选择]In which of the listed hydraulic systems will the installation of an oil cooler be necessary?（）
A. Constant tension mooring winch system
B. Hatch cover system
C. Watertight door system
D. Internal combustion engine hydraulic starter system
[单项选择]Which of the following hydraulic systems is not one of the three sub-division of the Hydraulic drive system?（）
A. Constant pressure system
B. Variable pressure system
C. Variable displacement system
D. Constant volume system
[单项选择]It is important with all hydraulic systems to ensure that interlocking arrangements provided for pump or motor control levers are （） before the pump driving motor can be started.
A. in the pert position
B. in the starboard position
C. in the neutral position
D. to be dismantled
[单项选择]A reservoir, as used in hydraulic systems aboard ship, is used to store hydraulic oilAnother function is to（）
A. act as a shock absorber
B. maintain the stored oil under pressure
C. act as a base or foundation for the power unit
D. eliminate pressure surges in the system
[单项选择]（） play a very important part in hydraulic systems by preventing interaction between different parts of the hydraulic circuit.
A. Motors
B. Check valves
C. Safety valves
D. Reducing valve
[单项选择]Which system(s) in the hydraulic systems of crane always hold(s) single side of load?（）
A. hoisting system only
B. hoisting system and luffing system
C. hoisting system and slew and slewing system
D. slewing system only
[单项选择]An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
A. aeration of the oil
B. contamination of the oil
C. pump cavitation
D. spongy actuator movements
[单项选择]If one hydraulic pump of an electro-hydraulic steering unit falls, the vessels steering can be initially and best maintained by using the （）.
A. trick wheel
B. accumulator
C. standby pump
D. telemotor
[名词解释] 漏出性出血（leakage hemorrhage）
[单项选择]Air leakage between the shaft and stuffing box packing in a centrifugal pump is prevented by （）.
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]Excessive air leakage into the suction side of a centrifugal pump would be indicated by which of the following operational problems?（）
A. The pump delivers full capacity when started, but gradually slackens off toan abnormally low flow
B. The pump packing gland overheats after short operating periods
C. The motor over-current protective device continually shuts the pump down
D. Pounding noises can be heard at the pump suction chest
[单项选择]Diesel engine blow-by is the leakage of combustion gases past the （）
A. oil rings only
B. compression and scraper rings
C. cylinder liner sealings
D. cylinder liner ring grooves
[单项选择]Either a low injection pressure or a leakage of piston rings is able to lead （）.
A. a high exhaust temperature
B. a high smoky exhaust
C. a high output
D. a high compression
[单项选择]The most common contaminate of governor hydraulic fluid is （）.
A. moisture
B. dirt
C. acid
D. air
[单项选择]Hydraulic machinery failures are commonly caused by misalignment of the system components and by （）.
A. hydraulic fluid contamination
B. excessive fluid friction
C. turbulent fluid flow
D. fluid pressure surges
