Flashcards in Module 4 Deck (29):
the device used in a hydraulic system to convert mechanical energy into hydraulic energy
the ratio of a pump's actual delivery rate to its theoretical displacement
the ratio of a pump's hydraulic power output to its mechanical power input
A hydraulic pump converts _____ energy into _____ energy.
Pumps classified by their principle of operation include _____ and _____ types.
Positive-displacement pumps have either a(n) _____ or _____ displacement.
Fixed-displacement pumps are _____ efficient than variable-displacement pumps.
The delivery rate or flow rate of a pump is commonly referred to as its _____.
To prevent overheating and internal slippage, a high-pressure pump is limited to a minimum operating _____.
Name the two ways in which pump efficiency is described.
The service life of a pump is specified in terms of operating _____.
External gear pumps can operate at pressures of up to _____ psi.
Internal gear pumps are used in hydraulic systems that have _____ speeds and _____ capacities.
Gerotor pumps are made without an internal gear _____.
A vane pump in which the rotor is placed off-center is said to be _____.
Pump vanes that are not spring-loaded are held in contact with the housing by both centrifugal and _____ pressure.
The fluid flow in a variable-displacement vane pump is changed by moving the _____.
The two most common types of piston pumps are _____ and _____ pumps.
Can piston pumps operate at flow rates over 1000 gym?
A hydraulic pump does all of the following except
a. convert mechanical energy into hydraulic energy
b. create a partial vacuum at the inlet
c. deliver the fluid to the outlet
d. produce the working pressure in the system
d. Produce the working pressure in the system.
Which of the following types of pumps is not a positive-displacement pump?
The volume of delivery of a fixed-displacement pump
a. can be changed by changing the physical arrangement of the pumping mechanism
b. can be changed by changing the pump's speed
c. cannot be changed
d. changes with variations in system pressure
b. Can be changed by changing the pump's speed.
The capacity of a pump may be specified in all of the following except
a. cubic inches per minute
b. cubic inches per revolution
c. gallons per minute
d. pounds per square inch
d. Pounds per square inch.
The efficient operating life of a pump is usually given in terms of
b. flow rate
c. fluid pressure
Because of their design, internal gear pumps are limited to applications having
a. low pressures and high speed
b. low speeds and high pressures
c. small capacities and high speeds
d. small capacities and low pressures
d. Small capacities and low pressures.
A vane pump of the unbalanced design can be identified by its
b. dual inlet ports
c. off-center rotor
d. special drive motor
c. Off-center rotor.
The vane tips of a vane pump are usually grooved or split to permit all of the following except
a. a larger contact area at the housing
b. better lubrication
c. free movement of the vanes
d. longer vane life
a. A larger contact area to the housing.
Variable-displacement vane pumps control fluid flow by
a. changing the discharge port
b. changing the inlet port
c. shifting the cam ring
d. shifting the housing
c. Shifting the cam ring.