hydraulics Flashcards
what is a fluid defind as (3)
a substance that readily takes the shape of a container
capable of transmitting power
can be a liquid or gas
what is the difference between a liquid and a gass (4)
can compress gas
liquid is incompressable
liquids are hydrolic
gasses are pnumatic
what is the equation to find out the pressure of hydrolics
pressure= force divide by area
what are the advantages of hydrolics (8)
reliable
simple and easy to understand
infinite speed range
easily reversed
ability to withstand overload
no spark risk
high tork at low speeds
1/2 of equivalent eletric motor
what are the disadvantages of hydrolics (4)
fire risk on mineral oil systems
noise
risk of contamination
less efficient 85-95%
what is denso tape (3)
used on upper deck
protects from the environment (corrosion) on dissimilar metals
kept in inflam stores
what temp do orings melt at
300 degrees
what do you need for working with o rings
(4)
pvc gauntlets
rubber boots
pvc coveralls
full fire visor
what are hydrolic systems used for (3)
steering/ control systems
deck machinery
weapon systems
what are the 2 catogories of hydrolic oils and what are the description
petrolium- inexpensive, general purpose
synthetic based- man made, specific purpose
what are the oils used in hydrolic systems and what are the descriptions (4)
ox30- red , subs
om33- yellow/orange , carriers
ox40-green , t45 t23
rust veto- during upkeep prevents rust
what are the hazards of oil (8)
can cause skin irritation
change oil soaked clothing immediately
skin irritation to be brought to med staff
always consult hazard data sheet
mineral oil poses fire risk- alll leaks to be cleaned
flexi hoses hoses to be in date for test
gauge glass valves to be shut when not in use
sutable precautions to be taken before welding or burning
what are the requirements of hydraulic fluid (3)
transmits power
flow easily
incompressible
how is there no seals in hydrolic systems (1)
oil creates the seals
a hydrolic fluid must (4(
be incompressable
good lubrication properties
good sealing properties
give up heat readily
what are the additives of oil and what do they do (5)
anti foam- prevents bubbles
anti oxidants- reduces sludge build up
anti corrosion- prevents corrosion/ rust
demulsibility- allows fluid to seperate from water
pour point depressants- stops freezing
what are the most common contaminants in hydrolic fluid (5)
airborne particles
construction dirt
dirt in new fluid
dirt produced by wearing in new systems
dirt from human sources
how do you reduce contamination (7)
good design
filtration and filter maintenance
operation of filter and clogging indicator
good working practices
gaurdian filter pack
caps on open ended pipes
clean working area
what are the 2 types of hydrolic systems
ringmain
standalone
what are the types of pumps in hydrolic systems (2)
dynamic displacement
positive displacement
what are the types of positive displacement pumps (5)
internal gear
vane pump
external gear
lobe pump
piston types (single/multi)
what does an actuator do (1)
converts hydraulic energy into mechanical motion
what does a drain leg do (2)
returns cooling oil back to the tank and sealing oil from actuator
what are the 2 types of accumulator
piston
bag
what are axial piston pumps
and what are they used for
(5)
variable copacity
bi directional flow
stabaliser sytems
cpp systems
steering systems
what are the 2 types of actuator
linear and rotary
what does a ganged valve do (1)
restrics and releives flow
what do swash plates do (1)
regulates pressure required in system
