Hydraulics Flashcards
What is a fluid defined as
As substance that will readily take the shape shape of its container
Capable of transmitting power
It can be a liquid or gas
What’s the difference a liquid and a gas
A gas is a fluid and will transmit power until pressure is equal, Gas is compressible.
A liquid is a fluid and will transmit power irrespective of pressure. Liquids are virtually incompressible.
Liquids are used in hydraulic systems
Gases are used in pneumatic systems
Some advantages of hydraulics are…
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
Some disadvantages of hydraulics
Fire risk with material oil systems
Noise
Risk of contamination
Less efficient (85-95%)
What are the two types of hydraulic fluids
Petroleum based - Mineral oils
Synthetic based - Man made
When working with fluorocarbon elastomers you must wear what PPE?
PVC gauntlets
Rubber boots
PVC coveralls
Full-face visor
Oils in use are and what colour are they?
OX30- Red
OM33- Yellow/Orange
OX40- Green
Rust veto- prevents corrosion
What are the 6 requirements for Hydraulic fluid
- Transmission of power
- Fluid must flow easily through the lines
- It must be incompressible
- Lubrication
- Sealing properties
- Cooling
The most common causes of contamination in hydraulic oil are
- Airborne particles an moisture
- Construction dirt
- Dirt in new fluid
- Dirt produced by wearing in new system
- Dirt from human sources
In a hydraulic system what is the three sets of pipework
Pressure supply
Return
Drain
Methods of reducing contamination
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 pipework Clean working area
Positive displacement pumps are used for hydraulic systems, what are the different types?
Internal gearwheel type External gearwheel type Vane type Lobe type Radial piston type Axial Piston Pump
Axial Piston Pumps are used on ?
Stabiliser systems
CPP systems
Steering systems
What are the two type of hydraulic systems on board ships
Ringmain system (used for secondary systems)
Stand alone Power Packs ( used for equipment’s that can affect operational capabilities)
What’s the purpose of a Actuator
Convert hydraulic energy into mechanical motion
There are two types
- Linear
- Rotary
Linear can either be Single or Double acting
