Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Test Review > Hydraulics Test: Valves , Pumps And Actuators, Symbols > Flashcards

Hydraulics Test: Valves , Pumps And Actuators, Symbols Flashcards

1
Q

Hydraulic systems

A

Transmit power

Use motor and actuators to transmit force

Use pressurized oil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Valves are used in a hydraulic system to ________ of an actuator?

A

Regulate pressure

Control speed

Change direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Pascals law states:

A

A fluid at rest in a confined space has pressure acting equally in all directions and at right angles when a force is applied.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

At 1000 psi, hydraulic only will compress _______%

A

1/2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

1 bar is equal to _______ psi?

A

14.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

If you have a pressure reading of 30 psi absolute this would be _______ gauge pressure at sea level?

A

30 - 14.7 = 15.3 Psig

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If you had a pressure of 1000psi acting on a cylinder piston of 3” in diameter what is the force in lbs it will push?

Force (lbs) = P(psi) x A (area)
Area = Pi x Rsquared

A

Area = 3.142 x 1.5 x 1.5
A = 7.07

1000 x 7.07 = 7068.6 lbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

If you have a 2 to 1 cylinder, this means:

A

The rod end annular area is equal to half the cap area.

The rod area is equal to the rod end annular area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Pressure in a hydraulic system is created by?

A

A resistance to flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Flow in a hydraulic system can be expressed by:

A

GPM

Ft/min

Ft/sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

If you have flow rate of 2 GPM and cylinder with a capacity of 1 gallon, how long would it take the cylinder to extend fully.

A

30 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Force =

A

Pressure x area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In the flow triangle, speed is equal to?

A

Inches per min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

You need a certain size cylinder to operate at 2ft / sec with a 20gpm pump. What diameter cylinder would you need?

V = cubic inches/minute
S= inches/min
A= square inches

GPM x 231 = cubic inches/minute
Speed = distance x 60 (60 seconds in a minute)

A = V / S

A

20 x 231 = 4620 inches per min
24 x 60 = 1440
4620/1440 = 3.21
Square roots of 3.21/.7854
= 2”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The change in diameter of pipe has a direct affect on hydraulic oil velocity. If you change out a 1” pipe ID to a 2 inch ID pipe the cross sectional area of the inside diameter of pipe increases by how many times?

A

4 times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The recommended velocities for a hydraulic pressure line (working line) is _______ft/sec

A

7-20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Good Laminar flow in a hydraulic system helps:

A

Reduce heat

Reduces the possibility of cavitation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Cavitation damage occurs in the pump inlet or outlet?

A

Outlet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Aeration occurs when air becomes mixed in the fluid and the bubbles are imploded causing damage to the pump. Air gets into the system by_______?

A

Leaky inlet fittings
Low fluid levels in the tank
Shaft seal on the pump leaking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Bernoulli’s principle

A

Has fluid in motion
States if there is a pressure increase, there will be a velocity decrease in the fluid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Work is force applied over a distance

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Power is equal to?

A

Work / time

Force x distance/time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

1 horse power actual is = GPM x psi x .0007

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

If you had a pump at 50 Gpm but only producing 30 Gpms the volumetric efficiency would be?

A

30/50 x 100 = 60 %

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

In an closed loop hydraulic circuit the return line goes back to the reservoir that is ________ times the volume of the rated capacity of the pump?

A

3/4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

A closed loop system the return line connected to the main pump inlet. It used a _________ pump to make up the fluid loss from the case drains?

A

Charge pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Hydraulic systems can operate at pressures exceeding 3000 psi if you come in contact with oils at that pressure it can kill you.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

A maximum pressure relief valve is put in the hydraulic system to?

A

Set the maximum force a cylinder will exert

Protect components in the system from overloads

Diverts access flow to the tank when the cylinder get to the end of its stroke. (Non variable pump)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Directional control valves (DCV) can be operated electronically, hydraulically, pneumatically and manually

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

When a hydraulic symbol has a diagonal arrow running through it, it means ?

A

Variable or adjustable in its output

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

A double acting cylinder that has two rod ends that are doing equal work in either direction.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

A pressure reducing valve is normally _______?

A

Open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

A check valve is closed when the ball is pressed against a v shaped seat in a hydraulic symbol.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

A sequence valve is used when?

A

You need to control the timing of two cylinders in a hydraulic circuit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Meter in flow controls are not used when?

A

Extending a cylinder with a tractive load.

(Load pulling down)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Bleed off flow controls are used in hydraulic systems instead of meter in and out flow controls because?

A

They are more energy efficient.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Cross-port relief or cushions valves help with shock loading in a hydraulic system circuit. They are used with hydraulic ______?

A

Motors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Counter balance have the pressure setting ?

A

Just above the load but below the load plus the system pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Deceleration circuits allow the cylinder to extend part way at full speed but then slow down near the end of the stroke by using a roller cam that shifts a valve so the hydraulic oil ___________?

A

To Flow through the flow control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

An unloading valve is used to

A

Depressurize part or all of the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

There are two designs of relief valves which one is more energy efficient?

A

Pilot operated/compound relief valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Pressure override is equal to ______

A

Full flow pressure minus cracking pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

In a vented relief valve the ________ is drained externally at a pressure. ___________ then the relief valve setting

A

Pilot stage

Lower

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Unloading valves are used in an accumulator circuit to relieve all the pressure. This is done by hooking up an on/off valve solenoid to the electric motor starter for the pump. When the pump is shut off the valve opens and dumps all the pressure back to the tank.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Pilot operated pressure reducing valves are used instead of direct acting pressure reducing valves because?

A

They have a wider range of adjustment and are more accurate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

If you had no pressure when adjusting a pilot operated pressure reducing valve the problems could be?

A

The valve is installed backward

External drain is plugged

There may be dirt on the check valve seat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

On a sequence valve if the 2nd cylinder does not move the problem is most likely

A

Spring tension to high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

If a counterbalance valve has a load Falling uncontrollably, you would _______ to fix it?

A

Increase the spring pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Brake valves are used on the discharge of hydraulic motors to?

A

Prevent oversweep when a overrunning load is applied

Prevents excess pressure build up decelerating or stoping a load.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

All pressure control valves are externally drained if there is pressure down stream of the valves.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Direction control valves can be:

A

Rotary

Sliding

Or

Poppet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Detentes help the valve hold the spool in different positions

A

True

53
Q

A single acting cylinder can be controlled by a

A

3 way 2 position valve

54
Q

A double acting cylinder can be controlled by a ________

A

4way 2 position valve

55
Q

A solenoid controlled, pilot operated directional control valve has the main stage spool shifted by ?

A

Hydraulic pressure

56
Q

If a solenoid controlled, pilot operated directional control valve will not shift. You can check to see if it shifts manually by activating the manual override button. (Located at the end of the solenoid) with a small screw driver. Pump needs to be running but power to valve must be off.

A

True

57
Q

A float centre in a directional control valve allows?

A

The A and B ports to flow back to tank

58
Q

A regenerative centre in a directional control valve is used with a 2 to 1 cylinder to?

A

Have equal pressures on both sides of the cylinder

Have equal speed in both directions

59
Q

A right angle check valve allows ?

A

3 times the flow of a check valve

60
Q

Pilot to open check valves have pilot pressure to push the ball off it’s seat and open it to flow.

A

True

61
Q

When using a meter out flow control on the cap end of a cylinder it is controlling the retraction of the cylinder.

A

True

62
Q

If a flow control has a bypass check valve you would be controlling flow in how many directions?

A

1

63
Q

Flow controls can have pressure compensators such as bypass restrictors types to_______?

A

Control the speed of the oil going through the valve

64
Q

The temperature compensator in a flow control valve helps keep a constant flow through the valve when _______ changes

A

Viscosity

65
Q

Stack valves use a sub plate that has a stack valves mounted on it. The first valve mounted on the plate is the ?

A

Maximum pressure relief valve

66
Q

The sub plate ends for stack valves have _______ port connections

A

Pressure and tank

67
Q

Screw in cartridge valves are _______ if they wear out?

A

Thrown away

Slip in cartridges can be rebuilt

68
Q

Slip in cartridges are used for larger flow rates the. Screw in cartridge valves

A

True

69
Q

Area ratios in the seating are of slip in cartridge valves can be?

A

1:1

1:1.1

1:2

70
Q

Proportional valves are?

A

More rugged than servo valves

71
Q

The spool in proportional valves have metering notches that help control the flow rate from the valve.

A

True

72
Q

The movement in a proportional valve is?

A

Proportional to the electric input

73
Q

Dither is rapid movement of the spool back and forth a few thousands of an inch to help ensure the valve will move freely

A

True

74
Q

The closed inner loop system uses LVDT’s to sense the spool position

A

True

75
Q

The plate and nozzle type pressure controls in a proportional valve are activated by?

A

The proportional solenoid

76
Q

________ motors are unique to servo valves

A

Torque motors

77
Q

Pick ups or sensors that measure position, pressure or velocity are called transducers

A

True

78
Q

Servo valves that control the movement of the Armature and the _________ that controls the position of the spool

A

Flapper nozzle

Jet pipe

79
Q

Hydraulic pumps create ________ and are __________ pumps

A

Flow

Positive displacement

80
Q

Hydraulic pumps have some internal leakage between sealing components which can be around _______%

A

5-15

81
Q

All hydraulic pumps have _______ and ________ chambers that create the pumping actions

A

Increasing inlet and decreasing outlet

82
Q

To change the output flow of a fixed displacement pump you would ?

A

Change the rpm of the electric motor

Change out the cartridge (vane pump)

Recirculate some of the oil back to the inlet with flow controls and a relief valve

83
Q

To change the output of an axial pump you would?

A

Change the angle of the swash plate

84
Q

Load sensing compensator with a pressure limiting sensor compensator is a highly efficient hydraulic pump

A

True

85
Q

The preload spring on a axial piston pump is a safety concern because?

A

It can fly out and hit you when you remove the retaining clip

86
Q

A bent axial piston pump can tolerate a high vacuum at the inlet, this allows it to be mounted above the fluid

A

True

87
Q

A variable displacement rotary pump uses a _________ that moves from side to side to change the volume of the pump

A

Reaction ring

88
Q

Radial piston pumps are driven in and out of the cylinder by a cam in the centre

A

True

89
Q

An unbalanced vane pump rotor is driven by a _________ that is supported by ball bearings at the drive end and_______\ bearings at the other side

A

Splined shaft

Needle

90
Q

A balanced vane pump has _______ 180 degrees apart and have _______

A

2 pumping chambers

A circular cam ring

91
Q

The vane pump uses centrifugal force to help seal the vane against the cam ring

A

True

92
Q

A small vane called an intra vane is used in combination with holes drilled from the outside of the rotor to the root of the vane to control the _________\

A

Vane tip loading and wear

93
Q

Always have the trailing edge of the vane in the cane pump facing the feed notch

A

True

94
Q

Combination in vane pumps would be _______ and cavitation would be _______

A

Circular scoring on the vane faces

And

Pitting on the outlet side

95
Q

Gear pumps have two basic designs internal gear and _______

A

External gear

96
Q

Gear pumps use needle bearings and bushings to help offset ________

A

Side loading from being unbalanced

97
Q

Flow through and external gear pump is

A

Around the gears and against the housing

98
Q

The crescent seal in an internal gear pump rotates with the?

A

It does not rotate

99
Q

The Gerotor internal gear pump is quit running because the treaty are shaped like lobes and are unique because the outer gear has at least one more tooth than the internal gear

A

True

100
Q

Gear pump is _____% efficient and a piston pump is ______% when new?

A

85

95

101
Q

Hydraulic cylinders convert ________ to ______ energy

A

Hydraulic

Mechanical

102
Q

With telescoping cylinders the first cylinder to move is the largest

A

True

103
Q

A single acting cylinder uses _______ to return the cylinder from extension?

A

Gravity and weight

Spring pressure

104
Q

A differential cylinder is a _______ cylinder

A

Double acting

105
Q

The component that keeps the rod clean and rod seal protected is the

A

Rod wiper

106
Q

Cusions allow for the cylinder to slow down at the end of the stroke and can be controlled by a

A

Needle valve

107
Q

Stop tube is used in a cylinder that is

A

Long and has side loading

108
Q

Clevis mounted cylinders move in a slight arc motion?

A

True

109
Q

O-ring boss ports are considered the best because they are?

A

Leak free

110
Q

Bleed ports in cylinders should be orientated with them at the top when the cylinder is mounted vertically so the air can bleed off

A

True

111
Q

When installing a new cylinder you should fill the cylinder with oil and once it is running _______

A

Cycle back and forth until all air is pushed out of the cylinder ( no squealing or jerky motion)

112
Q

Hydraulic motors are driven by

A

Hydraulic pumps flow

113
Q

Limited rotation motors have _______ number of shaft rotations

A

Less than one

114
Q

Displacement inside a hydraulic motor is measured in

A

Cubic inches per revolution

115
Q

Torque produced in a hydraulic motor depends on :

A

System pressure setting

Surface area of the motor components (vanes, gears, pistons)

Radius of rotating elements

116
Q

Volumetric efficiency is the input flow divided by the output flow

A

True

117
Q

The speed of a hydraulic motor depends on

A

The flow rate of the pump

The volume of the fluid pumping chambers in the motor

118
Q

External gear motors operate by meshing the gear teeth and driving the fluid between the outer edge of the gear and the housing

A

True

119
Q

When you assemble a gear motor and you find you cannot rotate the rotor by hand the problem is________

A

There is no problem it is assembled properly.

Tight clearance makes it hard to turn by hand

120
Q

When assembling orbiting gear motors and roller vane gerotors you must time the gears with the rotary valve (assembled in phase) if they are out 180 degrees the motor will

A

Rotate backward

121
Q

When using hydraulic vane motors they will have ________ to help seal the vanes against the cam ring before oil helps it turn over

A

Springs

122
Q

An in line axial piston motor has a swash plate set just about straight up and down will cause the pump _______ speed and ______\ torque

A

High

Low

123
Q

When removing the spool on a radial piston motor, make sure to mark its position with respect to the housing and also mark the crankshaft position in respect to the housing so you will not have the unit running backwards when you put it in operation

A

True

124
Q

All hydraulic motors and pump will have external drains mounted on their housings to

A

Drain fluids that are leaking by the internal seals

125
Q

This symbol represents

A

Pressure relief valve

126
Q
A

Double acting cylinder with cusion on both ends

127
Q
A

Pressure reducing valve

Always open

128
Q
A

3 way 2 position

Test Review (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions