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MK1 EOCT AUXILIARY EQUIPMENT > Hydraulics Systems > Flashcards

Hydraulics Systems Flashcards

1
Q

_____ relates to the use of confined fluids to transmit power, multiplying force and modifying motions.

A

Hydraulics

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2
Q

Hydraulics is based upon a principle discovered by the french scientist _______ in the 17th century.

A

Blaise Pascal

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3
Q

Hydraulics is widely used in the CG to perform various functions, including the following:

A
  • Steering systems
  • Booms/cranes
  • Winches and other deck machinery
  • Hydraulic presses
  • Fin stabilizer systems
  • Controller pitch propellars
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4
Q

Pressure applied to a confined fluid is transmitted undiminshed in all directions and acts equal force on equal areas and at right angles to them.

A

Pascal’s Law

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5
Q

Within Pascal’s Law are found the 3 areas of Hydraulics:

A
  • Pressure
  • Force
  • Area
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6
Q

Use the following 3 formulas when working with hydraulic systems:

A
  • Force = Pressure X Area
  • Pressure = Force / Area
  • Area = Force / Pressure
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7
Q

______ is defined as the measure of a bounded region or plane.

A

Area

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8
Q

______ is expressed in inches square (in2)

A

Area

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9
Q

________ is defined as anything which tends to produce or modify motion.

A

Force

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10
Q

_______ can push, pull or rotate and is usually expressed in units of weight. In hydraulics it is expressed in pounds (#, lbs.).

A

Force

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11
Q

______ is defined as force per unit area and is measured in pounds per square inch (psi).

A

Pressure

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12
Q

________ is created by resistance to flow, either by force (load) or restricting flow.

A

Pressure

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13
Q

Inside a Hydraulic Cylinder there are two working surface areas?

A

The 1st is the cap end** and the 2nd is the **net area.

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14
Q

Hydraulic pressure working on the ______ area forces the piston rod to extend.

A

Cap End

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15
Q

Hydraulic forces working on the _____ area forces the piston to retract.

A

Net

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16
Q

With the same pressures, the hydraulic cylinder produces greater force _________.

A

extending than retracting

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17
Q

What is the formula to calculate the cap end area of a hydraulic cylinder?

A

Area = D squared X .7854

(D = Diameter in inches)

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18
Q

Formula to calculate the piston area when the force and pressure are known.

A

Area = Force / Pressure

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19
Q

To calculate the amount of force being applied, multiply the pressure by the cylinder’s area. For extending use the cap area. For retracting use the net area. What is the formula?

A

Force = Pressure X Area

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20
Q

Calculating force for extension:

A

Extending

F = P X A

F = 200 psi X 6 in squared

F = 1200 lbs

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21
Q

Calculating force for retraction:

A

Retracting

F = P X A

F = 200 psi X 4 in squared

F = 800 lbs

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22
Q

Calculating maximum force:

A

Extending

F = P X A

F = 2500 psi X 8 in squared

F = 20,000 lbs

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23
Q

Calculating maximum retraction:

A

Retracting

F = P X A

F = 2500 psi X 4 in squared

F = 10,000 lbs

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24
Q

What is the formula to calculate area?

A

Area = Force / Pressure

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25
Q

Calculate the piston area when force and pressure are known.

A

Area

Area = Force / Pressure

A = 2000 lb / 500 psi

A = 4 in squared

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26
Q

To calculate the system’s pressure while moving a load, the force and the cylinder’s area must be known. What is the formula?

A

Pressure = Force / Area

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27
Q

Calculate cylinder pressure extending:

A

Extending

P = F / A

P = 1500 lbs / 10 in squared

P = 150 psi

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28
Q

Calculate cylinder pressure retracting:

A

Retracting

P = F / A

P = 1500 lbs / 5 in squared

P = 300 psi

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29
Q

When calculating the movement and force on a cylinder with pressure on both sides of the cylinder, the force exerted in each direction calculated first. Then subtract the force retracting from the force extending. View example of a differential pressure formula:

A

Force extending = Pressure X Area

Force retracting = Pressure X Area

Force extending = 500 psi X 4 in squared = 2000 lbs

Force retracting = 500 psi X 2 in squared = 1000 lbs

2000 lbs - 1000 lbs = Differential Pressure 1000 lbs

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30
Q

_____ is the ability or capacity to do work.

A

Energy

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31
Q

Also referred to as STORED ENERGY, _______ is present in a hydraulic system in the form of a FLUID PRESSURE.

A

Potiential Energy

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32
Q

Also referred to as ENERGY IN MOTION, ______ is present in a hydraulic system in the form of FLUID FLOW, represented by a MOVING ACUATOR.

A

Kinetic Energy

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33
Q

__________ states “Energy can neither be created, nor destroyed, but instead will simply be changed from one form to another”

A

The Law of Conservation of Energy

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34
Q

_________ energy changes into _______energy as speed is lost-what is gained in one energy form is lost in another.

A

Kinetic Energy changes into Potential Energy

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35
Q

_______ is defined as exerting force through a defined distance. In other words, how much effort is exerted moving something a certain distance.

A

Work

Formula: Work = Force X Distance

One way to express work is in foot pounds

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36
Q

_______ is the rate of doing work. An object is moved a fixed distance either slowly or quickly.

A

Power

Formula: Power = Force X Distance

                        Time

The faster an object moves over a fixed distance, the more power is required.

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37
Q

Formula for Horse Power:

A

1 HP = 100 lbs X 330 ft

          1 minute
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38
Q

In hydraulics, ___________ are used to determine horsepower.

A

Fluid Flow and Pressure

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39
Q

What is the best protection against unsafe practices when working with hydraulic systems?

A

Common sense and knowledge of the system

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40
Q

Where would you find the following components:

  • Reservior
  • Pump
  • Control valves
  • Motors (rotary actuators)
  • Cylinders (linear actuators)
  • Accumulator
  • Filters and Strainers
  • Fluid conductors and seals
  • Hydraulic fluid
A

Components of a hydraulic system

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41
Q

When a hydraulic system is operating incorrectly, the cause is generally traced to one of the following:

  • Contaminated hydraulic fluid
  • Wrong hydraulic fluid viscosity or type
  • Insufficient fluid in system
  • Air in the system
  • Damage
  • leakage

These causes result in a problem with one or more of the following fundamental elements of the system:

A
  • Flow
  • Pressure
  • Direction of flow
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42
Q

A problem with flow, pressure and direction of flow may cause one or more of the following symptoms to appear in the system:

A
  • Excessive heat
  • Excessive noise
  • Faulty operation
  • Incorrect flow
  • Leaks
  • Vibration
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43
Q

The tools most commonly used in the CG for troubleshooting hydraulic systems are:

A
  • Pressure Gauges
  • Flowmeters
  • Manufactures tech manual
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44
Q

Most common cause of failures, especially repeated failures in the same piece of equipment, is fluid ______.

A

Fluid Contamination

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45
Q

_______, which can cause fluid contamination, is another possible cause of failure in a hydraulic system.

A

Heat

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46
Q

When using a flowmeter, direct the return fluid to the _________.

A

Reservior

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47
Q

The fluid used in hydraulic systems has four functions:

A
  • Transmit power
  • Cool
  • Seal
  • Lubricate

In order for hydraulic fluid to perform these functions, verify it is the correct type, viscosity and free of contaminants.

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48
Q

_______ is the most important factor in keeping hydraulic systems operating properly.

A

Contamination Control

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49
Q

Dirt, sand, gasket/sealing materials, component wear particles or any solids within the hydraulic fluid.

A

Solid or particle contamination

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50
Q

The most common Liquid Contaminant in CG hydraulic systems is ______.

A

Water

51
Q

Any dissolved or free air or other gases in the fluid. It causes increased oxidation and reduced lubrication.

A

Air and gas contamination

52
Q

Chemical, solvent and microbial growth and any other type of contaminants.

A

Other Contaminants

53
Q

Fluid storage inspection and testing are detailed in ____.

A

NSTM, Chapter 556, Section 5

54
Q

For petroleum base fluids, such as _______ and ______ fluids, water content is less than 100 ppm is desirable.

A

MIL-L-17331 and MIL-H-17672 fluids

55
Q

Maximum allowable water content for MIL-L-17331 and MIL-H-17672 fluids is _____ ppm for any sample.

A

500 ppm

56
Q

________ fluids are somewhat hygroscopic (absorb water) with a maximum water content of 3000 ppm (0.30 percent).

A

MIL-H-19457

57
Q

For water emulsifying petroleum base fluids, a maximum water content of _______ is allowed.

A

20,000 (2.0 percent)

58
Q

_____________ is a water emulsifying fluid and in an emergency, is authorized for continued use at 100,000 ppm (10 percent) by TYCOM/NAVSEA.

A

Houghton PR 1192

59
Q

Detailed procedures for handling water contaminated hydraulic systems are found in _______.

A

NSTM, Chapter 556, Section 8.7

60
Q

Remove water from hydraulic fluid using several different methods?

A
  • Drain and fill
  • Settling and draining
  • Centrifuging
  • Evaporation
  • Filtration
  • Water absorbent filters
61
Q

________ convert mechanical energy from a prime mover, into hydraulic energy(pressure). This energy is used to operate an actuator.

A

Hydraulic Pumps

62
Q

Name two broad categories of Pumps:

A
  • Positive Displacement
  • Nonpositive Displacement

Nonpositive displacement pumps are not used in hydraulic systems

63
Q

Positive displacement pumps include the following types:

A
  • Gear
  • Vane
  • Piston
64
Q

________ is the quantity of fluid that passes through a pump in one revolution, stroke or cycle, expressed in cubic inches.

A

Displacement

65
Q

Output of the pump is considered “_______” because it is not significantly affected by resistance to flow.

A

Positive Displacement

66
Q

Most pump failures are attributed to one or more of the following:

A
  • Cavitation 10 - 12% frequency
  • Aeration 10 - 12% frequency
  • Contamination 80% frequency
  • Excessive heat 2 - 5% frequency
  • Overpressurization 5 - 6% frequency
  • Improper fluid 2 - 5% frequency
67
Q

_______ occur when pump inlet vacuum get high enough to pull entrapped air out of the hydraulic fluid.

A

Cavitations

68
Q

Cavitations occur with as little as ______.

A

5 inches Hg

69
Q

_______ is when air enters the fluid on the suction side of the pump.

A

Aeration

70
Q

Parts affected by contamination in a Vane Pump:

A
  • Vane tip to cam ring
  • Rotor to side plate
  • Vane-to-vane slot
71
Q

Parts affected by contamination in a Gear Pump:

A
  • Tooth to housing
  • Tooth to tooth
  • Gear to side plate
72
Q

Parts affected by contamination in a Piston Pump:

A
  • Shoe to swash plate
  • Cylinder block to valve plate
  • Piston to cylinder bore
73
Q

Name two types of rotary actuators.

A
  • Hydraulic Motor
  • Rotary Actuator
74
Q

Provides continuous rotation motion.

A

Hydraulic Motor

75
Q

Has a limited turning motion of less than 360 degrees. A hydraulic motor converts hydraulic energy into mechanical energy.

A

Rotary Actuator

76
Q

Types of motors

A
  • Gear motors
  • Vane motors
  • Piston motors
77
Q

_________ is used on motors to help prevent the prime mover from overloading.

A

Pressure Compensation

78
Q

Breakage of a motors output shaft is caused by either:

A
  • Shaft misalignment
  • Loads with excessive torque
79
Q

What?

  • Stores the hydraulic fluid not currently being used in the system
  • Allows space for expansion/contraction of the systems volume due to thermal changes
  • Allows gauges to expel from hydraulic fluid
  • Allows foreign matter to settle out from the hydraulic fluid
  • Allows heat to dissipate from hydraulic fluid
A

A Hydraulic Resevior

80
Q

A _______ is a type of actuator.

A

Hydraulic Cylinder

81
Q

It converts fluid power into mechanical force and linear (straight line) motion.

A

Hydraulic Cylinder

82
Q

The components of a hydraulic cylinder that require the most attention are the _______.

A

Seals and Pivots

83
Q

The two most common locations for seal failure with a hydraulic cylinder are the _____.

A

Rod and Piston Seals

84
Q

In a _______, the pressure in the net end is greater than in the cap end when extending the cylinder.

A

meter-out circuit

85
Q

Control valves are divided into the following categories:

A
  • Flow control valves
  • Directional control valves
  • Pressure control valves
86
Q

Regulates flow of fluid

A

Flow control valves

87
Q

Controls the driection of flow

A

Directional control valves

88
Q

Limits or reduces fluid pressure to:

  • relief valves
  • pressure reducing valves
  • pressure sequence valves
  • unloading valves
A

Pressure control valves

89
Q
  • no pressure
  • low or erractic pressure
  • variations in flow
  • excessive noise or chatter
  • overheating system
  • permature movement to second operation
  • pump fails to unload completely
  • faulty or incomplete shifting
  • cylinder creeps or drifts
  • overheating hydraulic fluid

What do these symtoms indicate when troubleshooting a hydraulic system?

A

One or more Valves may be at fault

90
Q

_________ are furnished in matched sets and are not available for individual replacement.

A

Directional control valve spools

91
Q

When repairing directional control valves, inspect the valve spools and bores for _____ and _____.

A

Burrs and Scoring

92
Q

The directional control valve spools become coated with impurites from the ________.

A

Hydraulic fluid

93
Q

When scoring or coating on a directional control valve is not deep enough to cause a leakage problem, polish the surface with ______.

A

Crocus Cloth

94
Q

Renew the directional control valve’s body and spool if __________ is excessive.

A

Scoring or Coating

95
Q

If a directional control valve’s action was erractic or sticky before removal, it may be unbalanced because of wear on the spools or body.

A

Renew the valve

96
Q

If system checks indicate low pressure, check for a weak relief-valve spring using a _____.

A

Spring Tester

97
Q

Each ______ is stamped with number, a pressure limit and the date of manufacture. Use this code when testing the cartridges.

A

Relief Valve’s Cartridge

98
Q

Test a valve’s cartridge for correct pressure setting by installing in a system and operating the system until you reach the valve’s ________.

A

Operating Pressure

99
Q

Three main types of accumulators are:

A
  • Spring loaded
  • Weight loaded
  • Gas charged
100
Q

What kind of accumulator is used most in CG hydraulic systems?

A

Gas Charged

101
Q

What two components of a hydraulic system are designed to reduce or eliminate certain types of contamination?

A

Filters and Strainers

102
Q

Properly functioning _______ are essential to a properly functioning hydraulic system.

A

Filters and Strainers

103
Q

_________ are devices whose primary function is the retention, by some porous medium, of insoluble contaminants from a liquid.

A

Filters

104
Q

________ are more course than filters, meaning larger particles will pass through.

A

Strainer

105
Q

_________ are normally rated in wire mesh numbers.

A

Strainers

106
Q

________ are normally cleanable, where filters are not.

A

Strainers

107
Q

_________ are most commonly located on the inlet or suction side of the hydraulic pump,but can be found elsewhere, such as resevior fill port or vent.

A

Strainers

108
Q

Common places filter are located on a hydraulic system:

A
  • In the pressure line just after the pump
  • In return line before entering the resevior
  • Before or in a component, kidney or bypass loop
  • Offline-a separate pump & filter or a portable filtering unit.
109
Q

Filters are located in:

A
  • reseviors
  • pressure lines
  • return lines
110
Q

_________ are classified as full flow or proportional flow.

A

Filters

111
Q

In ________, all the fluid passes through a filtering element.

A

Full-Flow Filter

112
Q

In a ___________, only a portion of the fluid passes through a filtering element during each cycle.

A

Proportional Flow Filter

113
Q

Filter elements can generally be classified into two groups:

A
  • Surface Type Element
  • Depth Type Element
114
Q

In this type of element, the fluid stream has a straight flow path through the element and contaminants are trapped on the surface of the element.

A

Surface Type Element

115
Q

In this type of element, the fluid stream is forced to pass through a multiple layer element and the multiple layers trap the contaminants.

A

Depth Type Element

116
Q

_______ are usually constructed of a fine metal mesh with pores larger than 50 microns.

A

Strainers

117
Q

_____ are most commonly installed on pump inlet lines inside the reservoir.

A

Strainers

118
Q

Two common types of strainers used in hydraulic systems are:

A
  • Wire Mesh
  • Edge Disk
119
Q

A strainer that consist of several layers of wire mesh.

A

Wire Mesh Strainer

120
Q

A strainer that consist of a stack of metallic disk, separated by metallic spacers.

A

Edge Disk Strainer

121
Q

The contaminants which are accumulated on the strainer are cleaned off using one of the following cleaning devices:

A
  • Edge Wound Type
  • Edge Disk Type
122
Q

Indications that the pump inlet strainer is clogged:

A
  • Pump noise caused by cavitation
  • High vacuum pressure at the inlet side of the pump
123
Q

What are a few ways to tell that pressure differential has beem reached and the filter element is clogged and needs replacement?

A
  • Pressure Guages
  • Mechanicla and Electrical Indicators
  • Bypass Valve Indicator

MK1 EOCT AUXILIARY EQUIPMENT (8 decks)

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