更多"Some pumps use packing as sealing g"的相关试题:
[单项选择]The various pumps and lines are （） to some extent so that each pump can act as an alternative for another.
A. interlocked
B. interconnected
C. interfered
D. interacted
[单项选择]Gear pumps are of positive displacement type pumps because they discharge a near constant amount of liquid （） pressure.
A. depending on
B. in relative to
C. regardless of
D. because of
[单项选择]The bearing of tailshaft sealing equipment, which adopting the oil nature circulation is hot, the reason is（）
A. the rotate speed fluctuation
B. the ventilation tube clogged
C. the main engine accelerate so fast
D. stormy waves
[单项选择]The tailshaft sealing arrangement found a little lube oil leaky and caused a lot of seawater into the bearing, the step should be taken as a makeshift is（）
A. dropping lube oil for lubrication, reducing the pollution to the sea
B. setting a temporary gravity oil tank and enhanced the position properly
C. lubricating with the used lube oil
D. lubricating with the fresh water and navigation in a lower speed
[单项选择]A bright shiny appearance of the sealing surfaces on diesel engine compression rings indicates（）
A. combustion gas blow-by
B. excessive lubrication
C. properly functioning rings
D. insufficient cylinder cooling
[单项选择]Positive displacement, helical gear pumps are well suited for pumping oil because （）
A. stuffing boxes eliminate the leakage problems usually associated with other gear pumps
B. it is not necessary to closely maintain design clearances with this pump
C. they are essentially self-priming and produce a high suction lift
D. these pumps are designed with extreme tooth angled
[单项选择]Hydraulic pumps most commonly used in steering systems are of the （）.
A. lobe type
B. screw type
C. axial piston type
D. volute type
[单项选择]Overgreasing of ball bearings installed on pumps will result in （）.
A. smoother pump operation
B. overheating of the bearing
C. reduced corrosion in the bearing
D. increased pump capacity
[单项选择]Regulations require that cargo pumps in tankers carrying grade D liquid cargo shall be isolatedfrom sources of vapor ignition by（）.
A. cofferdams
B. gastight bulkheads
C. passageways or living quarters
D. general cargo spaces
[单项选择]Cooling water pumps driven by direct reversing diesel engines are usually of the straight impeller vane type pump with a concentric housing to（）
A. facilitate bi-directional operation
B. provide the greatest pump efficiency
C. prevent pump clogging from marine growth
D. prevent cavitation at the pump outlet
[单项选择]Which of the following pumps belongs to centrifugal pump?（）
A. Piston pump
B. Screw pump
C. Diffuser pump
D. Water-ring pump
[单项选择]Centrifugal pumps are popular because they are very simple in construction,and produce smooth, constant, （） discharge.
A. non-pulsating
B. pulsating
C. positive
D. non-positive
[单项选择]Black areas on the sealing surfaces of piston rings indicate（）
A. lube oil pumping
B. rotating rings
C. gas pressure behind the ring
D. passage of hot gases
[单项选择]Shaft sealing in a centrifugal pump can be effected by （）.
A. the mechanical seal
B. packed stuffing boxes
C. either A or B
D. neither A nor B
[单项选择]The sealing function of the piston ring is brought about by the gas pressure above and behind the piston ring, which forces it （） against the bottom of the ring groove, and （） against the cylinder wall.
A. upwards；inwards
B. upwards；outwards
C. downwards；inwards
D. downwards；outwards
[单项选择]When fire pumps are used for other than firefighting service，each pipe connecting the other service (except for branch lines used for deck washing) must have a（）.
A. check valve installed in the line
B. shut off valve at a manifold near the pump
C. quick disconnect union within ten feet of the pump
D. regulator in the line set at 125 psi
[单项选择]Multiple fire pumps may be used for other purposes provided that one pump is（）.
A. on line to the fire main
B. kept available for use on the fire main at all times
C. capable of being connected to the fire main
D. rated at or above 125 psi
[单项选择]Under centrifugal pumps are the volute, diffuser, mixed-flow, axial flow and （） or regenerative types.
A. reciprocating
B. hydraulic
C. turbine
D. vane
