What are the two types of actuators
Linear and rotary
What is the force trying to stop a body from moving
Resistance
When dealing with energy what do you have to watch out for
The state or condition in which it was found
What is process to reduce friction between two moving parts
Lubrication
What is the force that causes movement over a distance
Work
What does SUS stand for
And what is it measuring
Saybolt universal seconds
Viscosity
How does a flow control valve work
Operates by resistance
What does ASTM stand for
American society for testing materials
What is the resistance of molecules sliding/moving past eachother
Viscosity
Common fluids used in a hydraulic system are:
Paraffinic and naphthalenic
The law of conservation states:
That energy can not be created nor destroyed although it may change from 1 form to another
When a volume of fluid flows through tubing with a given amount of time
Flow rate
An actuator converts hydraulic working energy into:
Mechanical energy
Varnish, lacquer and sludge are formed by:
High temperature oxidation
Presents of ____ in a hydraulic fluid can plug sensing orifices, cause moving parts to stick and wear excessively and act as a catalyst to oxidize oil.
Dirt
A high pressure line with a pinhole leak spraying an oil mist into the air is:
Combustible
Fire resistant fluid that is close to petroleum oil is:
Synthetic
If a pump is filled with liquid it is:
Primed
What component is designed to store fluid l, allow entrained air to escape and also dissipate heat?
Reservoir
At sea level one column of air, one sq inch weighs:
14.7 psi
T or F
Cavitation destroys metal surfaces and interferes with viscosity
False
T or F
Hydropneumatic accumulators in industrial systems use nitrogen.
False
T or F
Generation of heat by working energy traveling through a system to a point of work is system incompatibility
False
T or F
Major causes of air entrainment is leakage past the piston seals.
False
T or F
Pressure compensated past flow control vlvs are designed to meter pressure changes ahead or after orifice
True
T or F
Main pump with pressure compensator causes pump discharge to reduce when pressure increases
True
T or F
The sump strainer is on the return side
False
T or F
A pressure filter is in the circuit between the pump and system components
True
T or F
A flow control valve should be installed in the system to restrict fluid as it flows to the actuator
False
T or F
The flow path through a normally closed pressure reducing valve is one when fluid exerts enough pressure to counteract vlv spring pressure
True
T or F
In double acting single rod cylinder the extending stroke is faster than the return stroke
False
Liquid enters and is forced out of pump by?
Generating an increase and decrease of volume out of housing
The main function of hydraulic fluid is transferring power and:
Lubricating the internal surfaces of components
Dirt comes in all shapes and sizes and can enter the hydraulic system by:
Dirt built into the system, generated within the system, and added to the system
What is the most popular kind of piston pump
Axial piston pump
In a vane pump, if there’s an unbalance with more pressure on one side it cause:
Excess stress on drive shaft and bearings
Variable displacement pumps can vary output by?
Adjusting the squash plate, Cary position of cam ring and changing the size of fluid chambers
What type of piston pump do the pistons in one half of the circle of rotation generate an increase in volume and in the other half of rotation the pistons generate a decrease in volume
Axial piston pump
Which component is designed to store hydraulic fluid at system pressure and release when the system demand is higher then pump delivery.
Accumulator
Cylinder pistons have 3 different kind of positive seals:
Lip seal, cast iron piston rings and single bidirectional element
Why is entrained air a sealing problem with a hydraulic system
Pseudo cavitation
In hydraulic motors the torque required to move the load is:
Breakaway torque
What can cause the pump to not start and block fluid flow
Improperly maintained or sized sump strainer
What vlv reduces pressure changes beyond the vlv
Normally open pressure reducing vlv
A normally non passing control vlv which causes one operation before another is a:
Sequencing vlv
2 common scales measuring pressure?
Psig and psia
What type of pressure reducing vlv should prevent a cylinder from dropping a heavy load
Counterbalance vlv
Which cylinder component prevents piston from slamming against end caps on end of each stroke €===3
Cushions
A ____ type pump can be a variable displacement pump?
Piston
2 classifications of positive displacement pumps
Variable or fixed
Which directional control vlv is used for a single acting cylinder
2 position 3 way
What are the 3 types of reservoirs
Overhead, L-shaped and conventional
What directional control valve is used when controlling a 1 directional hydraulic motor on or off
2 way 3 position
What control vlv is used for 1 direction with a pilot line
Pilot operated check vlv
