307

Question 1

which characteristics of a fluid does a term specific gravity describe

Answer 1

density

Question 2

pressure is measured in ___ in the english system

Answer 2

pounds per square inch

Question 3

which of the following is not needed in order to calculate the work a hydraulic cylinder can do

Answer 3

power (ft-lb/min)

Question 4

pascals law states that pressure exerted on a confined liquid

Answer 4

is distributed equally throughout the liquid

Question 5

according to Bernoulli’s principal when fluid flow increases in a system the pressure

Answer 5

decreases

Question 6

a hydraulic fluid must be able to do all of the following except

Answer 6

compress easily

Question 7

a hydraulic fluid that exhibits little change in viscosity when heated is said to have a high

Answer 7

viscosity index

Question 8

the ability of fluid to penetrate into small clearances between closely fitted parts is determined by the fluids

Answer 8

viscosity

Question 9

which of the following when added to hydraulic fluid will limit oxidation

Answer 9

a chemical inhibitor

Question 10

the best method of controlling hydraulic fluid contamination is the use of

Answer 10

good maintenance procedure

Question 11

the ability of a filter or strainer to remove 100% of the containment particles of a particular size from a hydraulic fluid is called its

Answer 11

absolute rating

Question 12

when the maximum allowable pressure drop of a filter is reached the filter will

Answer 12

allow particles to pass through the medium

Question 13

the purpose of a filler in a hydraulic system is to

Answer 13

remove small contaminants

Question 14

depth fillers do not

Answer 14

have a long service life

Question 15

surface filter media made of sintered metal powders are used in high pressure systems because of their

Answer 15

thick mass

Question 16

the seperation of contaminants from hydraulic fluid in a reservoir is added by

Answer 16

slow fluid movement

Question 17

what is used in a hydraulic reservoir to aid fluid cooling

Answer 17

baffle

Question 18

to maintain the temperature of a hydraulic fluid effectively the reservoir should have

Answer 18

thin walls

Question 19

an air breather is installed on a fluid reservoir to

Answer 19

vent the reservoir

Question 20

peak hydraulic system demands are usually met by the use of a(n)

Answer 20

accumulator

Question 21

the resistance of a hydraulic system to fluid flow causes

Answer 21

pressure

Question 22

pump capacity is rated in all of the following terms exept

Answer 22

pounds per square inch

Question 23

the ratio of the actual delivery rate of a pump to its displacement is its

Answer 23

volumetric effieciency

Question 24

which of the following is NOT a type of gear pump

Answer 24

vane

Question 25

internal gear pumps normally are used in applications that have

Answer 25

pressures of less than 1000 psi

Question 26

the flow rate of hydraulic fluid through piping or taking is measured in

Answer 26

GPM

Question 27

pressure loss in a hydraulic line depends on the

Answer 27

flow velocity

Question 28

hydraulic lines should NEVER be constructed of

Answer 28

galvanized pipe

Question 29

in non critical applications having no severe stress safe working pressure of hydraulic piping are based on providing a safety factor of

Answer 29

6

Question 30

a disadvantage of using hose in hydraulic systems instead of piping or tubing is that the hose

Answer 30

is less permanent

Question 31

which of the following kinds of valves should be used in a hydraulic system to change the direction of motion of the cylinder

Answer 31

directional control valve

Question 32

a three way valve is identified by its three

Answer 32

paths

Question 33

the closing force of a direct acting solenoid valve is approximately

Answer 33

15 lbs

Question 34

the construction of a spool valve causes it to

Answer 34

be partially balanced

Question 35

a four way valve that can operate in three positions is called a

Answer 35

closed crossover valve

Question 36

the operating differential pressure of a relief valve is the difference between its maximum pressure and the

Answer 36

cracking pressure

Question 37

the flow from the outlet of a sequence valve is at

Answer 37

line pressure

Question 38

fluid pressure in one section of a hydraulic system is limited by a

Answer 38

reducing valve

Question 39

a shock suppressor is used in a hydraulic system as

Answer 39

protection against pressure surges

Question 40

a meter out flow control valve is used to regulate fluid flow from an

Answer 40

actuator

Question 41

straight line mechanical force is created by a

Answer 41

hydraulic cylinder

Question 42

the force exerted by a double acting piston is

Answer 42

less on the rod side

Question 43

a cylinder in which the retracting stroke is the power stroke is called a

Answer 43

pull type cylinder

Question 44

when a hydraulic cylinder is added to an existing system be sure that the

Answer 44

pump capacity is adequate

Question 45

mechanical shock is controlled in a hydraulic cylinder by means of a

Answer 45

cushioning device

Question 46

which of the following statements about hydraulic motors is true

Answer 46

they are all positive displacement pumps

Question 47

the pressure range of a hydraulic motor may vary from

Answer 47

100 - 5000 psi

Question 48

the overall efficiency of a hydraulic motor is defined as the

Answer 48

output HP divided by input HP

Question 49

a crescent shaped separator is used on some ___ gear motors

Answer 49

internal

Question 50

internal leakage in hydraulic gear motor is held a minimum by the use of

Answer 50

wear plates