更多"Gear pumps are of positive displace"的相关试题:
[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]In a diesel engine, a positive displacement type blower is usually （）
A. gear drive by the engine
B. driven by an exhaust gas turbine
C. driven by a camshaft
D. driven by separate motor
[单项选择]Gear pumps are （） type because they discharge a near constant amount of liquid regardless of pressure.
A. positive displacement
B. non-positive displacement
C. mixed-flow
D. axial-flow
[单项选择]The output volume of a positive fixed displacement pump can be changed only by （）.
A. changing the angle of the tilting plate
B. changing the speed of the pump
C. moving the slide block and rotor
D. moving the shaft trunnion block
[单项选择]A positive displacement pump is that where the volume of the pump chamber is alternately increased to （） and then decreased to （）.
A. draw the liquid in；force the liquid out
B. force the liquid out；draw the liquid in
C. suction；draw
D. deliver；outlet
[单项选择]Under rotary pumps are the gear, （）, cam-and-piston and screw types.
A. reciprocating
B. diffuser
C. turbine
D. vane
[单项选择]Gear pumps are （） because they discharge a near constant amount of liquid regardless of pressure.
A. negative displacement type
B. turbine type
C. positive displacement type
D. mixed-flow type
[单项选择]Which of the listed pumps is NOT a positive displacement pump?（）
A. Centrifugal
B. Reciprocating
C. Gear
D. Rotary
[单项选择]The gear and screw pumps are classified as （）.
A. variable stroke pumps
B. multistage pumps
C. positive displacement pumps
D. triple-ported pumps
[单项选择]Centrifugal pumps are non-positive and a fairly （） unit.
A. low pressure
B. low discharge
C. low speed
D. high pressure
[单项选择]The gear, screw, and vane pumps are all classified as （）.
A. variable stroke pumps
B. multistage pumps
C. positive displacement pumps
D. triple-ported pumps
[单项选择]Gear-type flexible couplings are often used in diesel engine drive trains because they（）
A. require no lubrication under normal operating conditions
B. compensate for gross misalignment in the drive train
C. are able to transmit high torque ,even where slight misalignment exists
D. will rapidly disconnect the engine from the line shaft
[单项选择]Displacement refers to the（）.
A. cubic capacity of a vessel
B. deadweight carring capacity of a vessel
C. gross tonnage of vessel
D. number of long tons of water displaced by a vessel afloat
[单项选择]A variable displacement system of hydraulic drives consists of （）.
A. a variable displacement axial piston pump
B. a constant displacement axial piston pump
C. a reciprocating piston pump
D. a centrifugal pump
[单项选择]I saw your man not operating the winch gear（）gear.
A. in
B. by
C. of
D. against
[单项选择]In a fixed displacement axial piston hydraulic motor, the speed is varied by（）
A. regulating the ratio between torque and speed via the torque limiter at the motor
B. directing the motor output flow through a bypass line
C. maintaining a constant flow and pressure input
D. controlling the input flow rate
[单项选择]The engine is reversed by axial displacement of the camshafts In order for this to be carried out, the cams are （） with inclined transition faces.
A. lathed
B. shaped
C. shrunk
D. developed
