[Hydraulics] Flashcards

1
Q

How may both rigid and flexible copper tubing be cut?

A

Tubing cutter or a hacksaw

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2
Q

What is the compressibility of hydraulic oil?

A

1/2 of 1% at 1,000 psi

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3
Q

Horsepower requirement for the energy medium used to drive the hydraulic pump in the system

A

Horsepower of prime mover

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4
Q

Resistance of a fluid to flow within itself

A

Viscosity

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5
Q

List PSI and diameter for:

1) Threaded piping
2) Welded, flanged-connected piping

A

1) Diameters up to 1 1/4 inches and pressures up to 1,000 psi
2) Exceeding 1 1/4 and 1,000 psi

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7
Q

Valve that is usually manually-operated and used to stop and start the flow of fluid

A

Stop valve

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8
Q

Types of filters

A
  • Proportional flow - a portion of system flow passes through filter
  • Full flow - all system flow passed through filter
  • Indicator type - flow filter that tells you when filter is getting dirty
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10
Q

Anything which tends to produce or modify motion

A

Force (push or pull)

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11
Q

Types of piston pumps

A

Axial (swash plate) and radial

Swash plate - main shaft is connected to it; also called a tilt box; by varying the angle of the swash plate, we will be able to vary the discharge of the pump

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12
Q

Which type of line is generally used for its resistance to vibration?

A

Flexible hosing

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13
Q

Troubleshooting rules

A
  • Find out as much about the problem as possible

* Never disassemble a component unless you are sure it is at fault

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14
Q

Pressure reading that does not take into account atmospheric pressure

A

Pounds per Square Inch Gauge (PSIG)

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15
Q

Perpendicular distance from the fluid level on the reservoir to the pump

A

Lift

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16
Q

Seven things about preventative maintenance

A
  • Follow PMCS schedule
  • DIRT is #1 enemy of a hydraulic system
  • Change or clean filters and strainers as required
  • Keep the environment clean
  • Always filter the fluid before you fill the reservoir
  • Visual inspection can be performed
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17
Q

Device in the fluid line used to trap contaminates from the fluid flowing through them

A

Strainers

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18
Q

1) Condition where entrapped air is pulled out of the fluid and erodes port materials
2) How is it caused?

A

1) Cavitation

2) Too high of an inlet line or inlet vacuum

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20
Q

Define types and sizes of copper tubing

A

Type K - heavy wall (hard and soft)
Type L - medium wall (hard and soft)
Type M - thin wall (only hard)

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22
Q

What kind of line is used in hot and cold water distribution systems and hot water heating systems?

A

Copper tubing

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23
Q

System in which return oil from the actuator is directed to the reservoir to be picked up by the pump and recirculated

A

Open loop system

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24
Q

Two types of pipe benders

A
  • Internal - used when both ends flared

* External - used when one end flared

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25
Q

Rotary thrust or turning force of a motor, engine, or wrench

A

Torque

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26
Q

Law that states “Pressure applied to a confined fluid is transmitted undiminished, and in all directions, and acts with equal force on equal areas and at right angles to them.”

A

Pascal’s Law

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27
Q

What are the two types of tubing used for hydraulic lines?

A

Seamless and electric-welded

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27
Q

1) The ability or capacity to do work

2) What are its two forms?

A

1) Energy

2) Potential energy (pressure) and kinetic energy (flow)

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29
Q

Pressure reading that is equal to gauge pressure plus atmospheric pressure

A

Pounds per Square Inch Absolute (PSIA)

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30
Q

What stores high pressure for future use? Used in hydrostatic systems to develop flow; most common is gas-charged (dry nitrogen)

A

Accumulator before working on a circuit, make sure all pressure is relieved (hydraulic only)

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32
Q

Types of bourdon tube gauges

A
  • Simplex - designed only for reading pressure
  • Duplex - measures two different pressure at the same time and both are reading on the same scale
  • Compound - designed to measure pressure and vacuum
  • Vacuum - designed to only measure vacuum
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33
Q

1) Simple relief valve

2) Compound relief valve

A

1) High override pressure (bad)

2) Low override pressure (good)

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34
Q

Force applied to a unit area; resistance to flow

A

Pressure

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35
Q

What is gained in force is..

A

lost in distance

36
Q

Condition where air is entering the inlet side of a pump

A

Aeration

38
Q

Perpendicular distance from the pump discharge to the highest point in the discharge line

A

Head

40
Q

Law that states “Energy can neither be created nor destroyed”

A

Law of energy conservation

41
Q

How are strainers and filters rated?

A
  • Strainers - rated in mesh

* Filters - rated in microns

42
Q

What are the three pressures associated with pressure relief valves?

A

Cracking, full flow, and override pressure

43
Q

List type of linear actuators

A

Single-acting

Double-acting
• Differential
• Non-differential

44
Q

Types of vane pumps

A

Unbalanced, unbalanced variable displacement, and balanced

45
Q

Converts mechanical energy to hydraulic energy

A

Hydraulic pump

46
Q

Basic requirements of circulatory system

A
  • Lines
  • Terminal fittings
  • Supports
  • Lines with smooth interiors
  • Kept clean from all sources of contamination
47
Q

Valve used for quick opening and closing

A
  • Plug valve

* Butterfly valve never paint

48
Q

Three major groups for troubleshooting

A

• Energy group
- prime movers
- electrical source
- internal combustion engines
• Mechanical group
- check couplings for looseness or damage
- check for binding linkages
• Fluid group
- LEAKS are the most common source of trouble
- internal leaks cause losses in efficiency
- external leaks are fire and safety hazards

49
Q

Amount of space occupied in three dimensions

A

Volume

49
Q

Temperature at which a fluid’s vapors will ignite

A

Flashpoint

51
Q

Valve used to protect the system from overloading

A

Relief valve

52
Q

Types of hydraulic fluids

A
  • Petroleum base

* Synthetic fire resistant

53
Q

Measurement of a bounded region or plane, or the surface of a solid

A

Area

53
Q

System in which the fluid discharged from the actuator is recirculated at low pressure back to the pump inlet instead of being returned to the tank

A

Closed loop system

54
Q

What are the three types of lines in liquid-powered systems?

A

Pipes, tubing, and flexible hoses

55
Q

What are the two types of fittings?

A
  • Solder - used with either rigid or flexible copper tubing
  • Compression (flared) - used only with flexible copper tubing; principle use is in air piping and fuel-oil lines for their vibration resistance
56
Q

Device which synchronizes two identical cylinders’ speed regardless of load balance between them

A

Flow divider

57
Q

What is the greatest aid to troubleshooting?

A

Confidence in knowing your system

58
Q

What are the normal and maximum operating percentages?

A
  • Maximum normal is 50%

* Maximum is 75%

59
Q

The rate of doing work or expending energy

A

Power

60
Q

Any force which stops or retards the movement of a body

A

Resistance

60
Q

Exerting a force through a definite distance

A

Work

62
Q

Volume of liquid that can pass through a pump, motor, or cylinder in one revolution

A

Displacement

62
Q

Types of gear pumps

A

External gear: spur, helical, and herringbone

Internal gear: gerotor (ring gear)

63
Q

Positive displacement pump whose output cannot be made variable

A

Fixed displacement pump

63
Q

How are pumps rated?

A
  • Flow in GPM
  • Maximum Operating Pressure (MOP)
  • Given drive speed
64
Q

Valve with long tapered needle and seat

A

Needle valve never over-tighten

65
Q

Converts hydraulic energy to mechanical energy

A

Actuator

66
Q

Pump that delivers a set quantity of fluid for each revolution or stroke

A

Positive displacement pump (hydrostatic)

67
Q

Positive displacement pump whose output can be changed to suit operating conditions

A

Variable displacement pumps

68
Q

Where are the strainers and filters in relation to the pumps?

A

Strainers are before pumps and filters are after pumps

69
Q

Device in the fluid line used to trap fine particles and prevent them from remaining in the system

A

Filter

70
Q

Device that is used to create flow by using an outside source of power (prime mover)

A

Pump

70
Q

Amount of liquid flow that a pump will produce in a given time

A

Delivery

71
Q

Function of confined fluids

A
Transmit power (liquid pressure)
Multiply force (liquid pressure)
Modify motion (liquid flow)
71
Q

Describe the two types of flow

A

Laminar: a smooth, parallel flow path with fluid particles traveling in a straight line, undisturbed

Turbulent: Upset, erratic flow path with fluid particles colliding with each other

71
Q

Valve used for straight lines of flow; has either rising stem or non-rising stem, and is difficult to repair

A

Gate valve

71
Q

List the two mechanical and soldering techniques

A
  • Single flare - 45 degree flare on end of tubing

* Double flare - 45 degree flare on end of tubing which is doubled over

72
Q

Lightweight unit you can use to check or troubleshoot a hydraulic-powered system on the job or in a maintenance shop

A

Portable hydraulic-circuit tester

73
Q

Valve used to direct the flow of fluid to a specific point or component

A

Directional control valve