Hydraulic Principles Flashcards

1
Q

Describe pascals law

A

PRESSURE applied on a confined FLUID is transmitted UNDIMINISHED in all directions and acts with equal FORCE on equal AREAS at RIGHT angles to them

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2
Q

Describe Bernoullis principle

A

In a system with a CONSTANT FLOW RATE, the ENERGY is transformed from one form to another each time the pipe CROSS-SECTIONAL AREA changes

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3
Q

When is turbulent flow used

A

When FLUSHING the system

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4
Q

How is flow measured

A

Measured in velocity and flow rate

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5
Q

Why is water not used as a hydraulic fluid? (2)

A

Lack of lubricating
Corrosive

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6
Q

What is the definition of viscosity

A

Measure of a fluids resistance to flow

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7
Q

What is viscosity measured in?

A

Centistokes

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8
Q

What are the two types of pumps

A

Hydrodynamic (non-positive)
Hydrostatic (positive)

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9
Q

What are the characteristics of multi cylinder pumps? (4)

A

Highly efficient
Wide range of capacities
Variable output
Large HP applications

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10
Q

What are the 3 basic types of actuators?

A

Linear
Rotary
Semi-rotary

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11
Q

What is the Procedure for the motor leakage test

A

Isolate RETURN LINE
Break system on the DRAIN LINE
Supply oil to the actuator by operating the DIRECTIONAL CONTROL VALVE
Collect oil from the DRAIN LINE and time how long it takes to collect 1 PINT
Take TEMPERATURE of the oil and repeat on opposite RETURN LINE

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12
Q

What conditions mandate a oil change?

A

Degregation of base oil
Depletion of additives

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13
Q

Identify malpractices in RN hydraulic pumps and motors

A

Changing filters
Running too hot
Using incorrect oil
Wrong filter locations
Not self priming

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14
Q

What four positions are on a flushing valve?

A

Normal
Flush return
Flush drain
Test

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15
Q

Describe the operation of a flushing valve

A

Depressurise hydraulic system
Remove locking piece
Slacken back gland but to avoid damage to disc valves
Move valve to required position
Retighten gland but
Replace locking pieces
Re-pressurise system

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16
Q

Describe how a hydraulic bypass valve works

A

At a preset pressure a relief valve opens allowing a control signal to the unloading valve, opening the valve

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17
Q

What are the 3 contaminants?

A

Air
Water
Particulate

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18
Q

What effects would air in the system cause?

A

Air entrainment
Heat
Dieseling

19
Q

What effects would particulates in the system cause?

A

Scoring
Wear
Blocked filters
Blocked valve port

20
Q

What effect would water in the system cause

A

Erosion
Corrosion
Emulsification

21
Q

How are Swagelok fittings installed?

A

Insert the pipe into the fitting so the pipe rests firmly on the shoulder of the body
Scribe the nut at the 12:00 position
Hold the body in a vice
Tighten the nut 1 1/4 turns

22
Q

When must the Hydraulic seating unit be used?

A

When the fitting is over 25 mm
(1 inch)

23
Q

What are the Methods of fault finding

A

Hit and miss approach
Shutting down hydraulic machines
Line maintenance

24
Q

Fault finding procedure

A

What do I check?
What do I check with?
Where do I check?
What do I expect to read?
What do I check?

25
Q

Requirements of repacking stabiliser glands whilst afloat

A

Adhere to SOPs
Water integrity must be maintained
Fleet diving group required to assist
Personal wearing dry suits
Check all BRs and S2022a

26
Q

What is the flight deck crane hydraulic system comprised off?

A

Hydraulic power pack
Air blast cooler
Old control manifold
Dual joystick lever operated controllers

27
Q

What valves do control units contain?

A

Speed control valve
Direction control valve
Brake valve
Flow valve
Lowering valve
Pilot operated non-return valve
Throttle and non-return valve

28
Q

What are the 4 Types of filtration systems?

A

Full flow
Filtration by settlement
External filtration
Bypass filtration

29
Q

What are the types of water contamination and their PPM?

A

Dissolved water <200PPM
Suspended water 200-300PPM
Separated water > 500PPM

30
Q

What is a use of flexi hoses?

A

To allow for temporary access, eg flushing

31
Q

What are the 2 category’s of seals?

A

Static
Dynamic

32
Q

What are dynamic seals used for?

A

Sliding motion
Rotating motion

33
Q

What are the service life’s of flexi hoses?

A

CAT A - 5 years
CAT B - 10 years
CAT C - 15 years
CAT D - on condition
PTFE - 15 years

34
Q

What is the name of the hydraulic hose register?

A

S3171

35
Q

What are the safety precautions taken with steering gear?

A

Warning notices
OOD/OOW permission
Screening/ guards
Fire Hazard

36
Q

What is used to check faults on hydraulic systems?

A

Pressure transducer and recorder
Measuring jar and stopwatch
Temperature gauge or thermometer
Thermocouple
Noise meter
Particle counter

37
Q

What is the procedure for shutting down hydraulic machines?

A

Lower/ mechanically secure all suspended loads
Exhaust pressure locked in the system
Drain down all accumulators
Discharge both ends of intensifiers
Isolate electrical control system
Isolate the electrical power supply

38
Q

What are the first second and third line service when conducting line maintenance

A

First line —> maintenance and troubleshooting carried out
Second line —> investigation and repair of component
Third line —> investigation, overhaul and retest

39
Q

When using the PCM 400 what are the results of particulates in a sample

A

5 micron count and 15 micron count

40
Q

What are the 2 safety supervisor bypass valves?

A

V3 & V4

41
Q

What is an example of a rotary actuator?

A

Windlass

42
Q

What is an example of a semirotary actuator?

A

hydraulic valve

43
Q

What is an example of a linear actuator?

A

Gash Compactor