403 - Chapter 15 Flashcards
What are the four primary functions of a hydraulic fluid?
Transmit power
Lubricate
Seal
Dissipate heat
Name ten properties that a hydraulic fluid should possess.
Viscosity Viscosity Index Pour Point Lubricating ability Oxidation resistance Anti-wear Compatibility with system Rust protection Corrosive protection Demulsibility
Specific weight
Weight density. Weight per unit volume.
Density
Mass per unit volume.
Specific gravity
Weight density of the fluid divided by the weight density of water.
What is the difference between force and pressure?
Pressure is force per unit area.
Viscosity
Measures the resistance to flow.
Viscosity index
Measures the physical influence on viscosity of the oil with a change in temperature.
Absolute pressure
Pressure measured relative to a vacuum.
Absolute pressure = gauge pressure + atmospheric pressure
Vacuum
State of negative pressure.
DCV
Directional control valve
3 types of DCV:
Push button
Lever operated
Solenoid operated
1/#2 in naming a DCV
#1: number of parts (P, T, A, B) #2: number of stages (extend, retract, no action)
Flow Control Valve
Can control direction of flow or flow control rate.
10 types of valves:
Directional control valve Check valve Flow control valve ( bidirectional and unidirectional) Manual shut off valve Gate valve Ball valve Globe valve Butterfly valve Needle valve
