Hydraulics Flashcards
Annular area is?
Base area - rod area
Hydrodynamics are high flow low pressure systems hydrostatic is
High pressure low flow
Double the diameter = 4 times______?
The power and 4 times slower
Psi A is?
Psi G is?
Psi a is absolute and
Psi g is calibrated to atmospheric pressure (gauge starts at 0)
1 bar = _____ psi
1Atm = _____ psi = _____ bar
- 50 psi
14. 7 psi = 1.01 bar = 1 Atm
The resistance to flow creates
Pressure
An example of a pressure loss is
Long lines
Restrictions
Improper fittings
A force related complaint would be a ?
Pressure problem
A complaint of speed of unit would be a ?
Flow problem
An example of a non positive displacement pump is
Water pump ( rotors don’t contact walls just turn fluid)
The max low efficiency of a pump is
80%
What is the ideal efficiency?
Ideal would be 95% Mechanical efficency of 5% automatically withdrawn
The inlet is bigger on a pump to?
Never starve the pump and
Prevent cavatation
The measure meant of a micron is?
One millionth of a meter
Characteristics of hydraulic oil are
Prevents rust, the formation of sludge, varnish and gum, corrosion and pitting Retain stability, maintain viscosity for a wide temp range
When viscosity is to high it causes
Increased power to drive system increased temps, greater pressure drops , sluggish operation and greater retention of air
When viscosity is too low
Increased internal leakage ( causeing greater heat)
Actuator output speed decreased due to increase internal leakage
Excessive wear reduced oil strength
Oil viscosity is measured in 3 ways
Absolute viscosity
Kinematic viscosity
Relative viscosity
Absolute viscosity measures?
The force per unit area requires to move two surfaces with a film of oil
(Centipoise cP)
Kinematic viscosity measures?
Amount of time required for a given volume to flow through a capillary tube. (Centistoke cSt)
Relative viscosity measures ?
Measures amount of time for a given quantity of oil to flow through a standard orfice while being held at specific temp ( saybolt universal seconds SUS)
ISO stands for
International standards organization
SAE stands for
Society of automotive engineers
The rate of oxidation in hyd oil depends on
Amount of air the oil is exposed to
The temp of oil(dramatic effect)
The chemical makeup of oil
