Hydraulics Flashcards
What is the definition of a fluid
It’s a substance that will readily take the shape of its container
It is capable of transmitting power
It can be a liquid or gas
What are the advantages of hydraulics (8 answers)
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
What are the disadvantages of hydraulics (4 answers)
Fire risk with mineral oil systems
Noise
Risk of contamination
Less efficient 85-95%
Denso steel working mastic and PVC self adhesive tapes give off toxic gases when ignited. Where should they be used and stored?
They should only be used on upper deck
They should be stored in flammable stores
Pipework sealing joints carry “O-rings” that are made of fluorocarbon elastomers. At what temperature will they give off toxic gases and what is the name of the toxic gas emitted
At extreme temperatures above 300 degrees, such as fire, fluorocarbon elastomers will give off toxic gases including hydrogen fluoride
What PPE must you wear when working with fluorocarbon elastomers
PVC Gauntlets
Rubber boots
PVC coveralls
Full-face visor
What are the two types of hydraulic fluid
Petroleum based - general purpose, mineral oils
Synthetic based - man-made for specific purpose
What are the oils used and their colour indication
OX30 - Red (synthetic oil for hydraulics on submarines)
OX40 - Green (synthetic oil for T23/T45)
OX33 - Yellow (general purpose petroleum based oil, T22/T42/CVS)
Rust veto - Substitute for hydraulic fluid during upkeep periods to prevent corrosion
What are the requirements for hydraulic fluids
The main requirement is transmission of power
Fluid must flow easily through lines
It must be incompressible
Lubrication is another important requirement
Sealing properties
Cooling is another role for hydraulic fluid
What are the common causes of contamination in hydraulic oil
Airborne particles and moisture
Construction of dirt
Dirt in new fluid
Dirt produced by wearing in new system
Dirt from human sources
What are the methods for reducing contamination in hydraulic oil
Good system design
Filtration and filter maintenance
Operation of filter and clogging indicators
Good working practises
Use of guardian filter pack
Caps should be fitted to open pipework
Clean working area
What types of pumps are used for hydraulic systems and what are the different types
Positive displacement pumps are used, the different types are:
Internal gearwheel type
External gearwheel type
Vane type
Lobe type
Radial piston type
Axial piston pump (Use a swash plate)
What are axial pumps used on
Stabiliser systems
CPP systems
Steering systems
What do actuators do and what are the two types
Actuators convert hydraulic energy into mechanical motion
There are two types: linear and rotary
Linear actuators can either be single or double acting
What is an accumulator
Stores energy and smooths out pulsation, they are used as a surge or pulsation dampener
