Hydraulics

Question 1

Fluid definition

Answer 1

It is a substance that will readily take the shape of its container
It is capable of transmitting power
It can be a liquid or gas

Question 2

What is the hydraulic multiplication triangle

Answer 2

F=A x P

Force = Area x Pressure

Question 3

What are the advantages of hydraulics

Answer 3

It is reliable 
Simple and easy to understand 
Infinite speed range 
Easily reversed
Ability to withstand overload 
No spark risks 
High torque at low speeds 
1/12 size of equivalent electric motor

Question 4

What are the disadvantages of hydraulics

Answer 4

Fire risk with mineral oil system
Noise
Risk of contamination
Less efficient (85-95%)

Question 5

What tapes give off toxic gases when ignited

Answer 5

Denso steel working mastic tape

PVC self-adhesive tapes

Question 6

Where is tape stored

Answer 6

In the flammable store

Question 7

What PPE needs to be worn when working with fluorocarbon elastomers

Answer 7

PVC gauntlets
Rubber boots
PVC coveralls
Full-face visor

Question 8

What are the 2 types of hydraulic fluid and what are their properties

Answer 8

Petroleum based - general purpose mineral oils

Synthetic based - man made, for specific purposes

Question 9

What are the different oils used and what colour are they

Answer 9

OX30 - red
OX33 - yellow/orange
OX40 - green

Question 10

What is OX30 used in

Answer 10

Hydraulic systems on submarines

Question 11

What is OM33 used on

Answer 11

A general purpose petroleum based hydraulic oil used in all the hydraulic systems on T45, T22 and CVS

Question 12

What is OX44 used for

Answer 12

A synthetic oil used in hydraulic systems on T23’s, T45’s and all future projects

Question 13

What is rust veto used for

Answer 13

Used during upkeep periods where hydraulic oil has been removed from a system, it is put in as a substitute for the hydraulic fluid to prevent corrosion

Question 14

What are the requirements of a hydraulic fluid

Answer 14

The main requirement is for the transmission of power 
Must flow easily through lines 
Incompressible
Lubrication
Sealing properties 
Cooling

Question 15

What are the most common causes of contamination in hydraulic oil

Answer 15

Airborne particles and moisture 
Construction dirt 
Dirt in new fluid 
Dirt produced by wearing in new system 
Dirt from Human Sources

Question 16

What are the methods for reducing contamination

Answer 16

Good system design 
Filtration and filter maintenance 
Operation of filter and clogging indicators 
Good working practices 
Use of guardian filter pack
Caps should be fitted to open pipe work 
Clean working area

Question 17

What are the different types of positive displacement pumps

Answer 17

Internal gearwheel type 
External gearwheel type 
Vane type 
Lobe type 
Radial piston type 
Axial piston pump

Question 18

What are positive displacement pumps used for

Answer 18

Hydraulic systems

Question 19

What are axial pumps used on

Answer 19

Stabiliser systems
CPP systems
Steering systems

Question 20

What does the actuator do

Answer 20

Converts hydraulic energy into mechanical motion

Question 21

What are the two types of actuator

Answer 21

Linear and rotary

And can be either single or double acting

Question 22

What does an accumulator do

Answer 22

Store energy to smooth out pulsations. They are used as a surge or pulsation dampener or absorber