S Hydraulic System Principals Flashcards
What is the purpose of hydraulic systems?
To operate systems that would require a high physical effort
What is fluid static pressure?
The resulting energy of the fluid (temperature) and the force of its own weight
Where is static pressure constant?
Along a depth line
Pressure equation
P = F/A
What happens if you increase the output forces?
You increase the piston area and reduce the output stroke
What is the equation for hydraulic piston stroke?
Input force x input stroke = output force x output stroke
What is a passive hydraulic system?
Hydraulic systems powered by human effort
What is an active hydraulic system?
A powered system, driven by a hydraulic pump
What are the 2 types of active systems?
- Close centred
2. Open centred
What is a closed centred system?
Constant pressure all the time
What is an open centred system?
Pressure only when demanded
What is the pressure of a typical airliners hydraulic system?
3000-4000psi
What are the 9 desired properties of hydraulic fluid?
What are the 2 types of hydraulic fluid?
Mineral and synthetic
What colour is mineral hydraulic fluid?
Red
What colour is synthetic hydraulic fluid?
Purple
Why should hydraulic fluid types not be mixed?
The wrong fluid may seriously damage parts of the system, especially seals
What precautions should be taken when handling hydraulic fluid?
It is very corrosive, wear gloves and eye protection
5 main advantages of a hydraulic system?
- Provide large amounts of power to remote services
- Little energy loss in the transmission of power
- Leaks are easy to spot
- Lighter than equivalent mechanical system
- Provide power advantages for operation of heavy services
5 main disadvantages of hydraulic systems?
- Highly corrosive
- Forces generated require strong structures
- Can still be quite heavy
- Susceptible to fluid contamination and damaged lines
- Fluid is a health and environmental hazard
