Hydraulics Flashcards
What is the 3 bits of numbers you get with a cylinder in order?
Piston size
Stroke
Rod size
What is the purpose for wipers?
Clean dust / dirt when extending back cylinder
What is a stop tube?
It restricts from over extending.
What are cushions
Special “cushions” built into each end for less wear and tear on cylinders. (Adjustable)
What is a prime mover?
Power source
Ex- hand pump , electric motor.
When starting up a system what is one thing you need to complete before hand?
Purge the system with air
How is mechanical advantage gained with hydraulics?
By using pascals law (does this by acting As a force multipiler)
How is fluid flow measured?
The volume of fluid passing a given point in a unit of time.
What is laminar?
Fluid at the outer walls of the conduction moves more slowly than fluid in the centre of the conductor.
What is turbulent flow?
When smooth flow is disrupted, the fluid particles move in a random pattern rather than parallel to the direction of flow
What is the purpose of DCV
Used to control the direction of hydraulic fluid flow
What are the two types of spools for dcvs
Rotary or sliding
What is the law of conservation of energy
Energy cannot be destroyed, but it may be converted from one from to another
What does pascals law state?
Pressure applied to a confined fluid at rest, force is transmitted equally in every direction and always at right angles to the containing surface
What does Bernoulli principle state?
That if the flow rate is constant, the sum of the kinetic energy and the potential energy at various points in the system is constant
What are cylinders used to create?
Linear Motion
What are motors used to create?
Rotary Motion
What is friction?
The resistance to relative motion between two bodies
What are the main causes of excessive friction in hydraulic lines ? (4)
Excessive length of lines
Excessive velocity (B/C the lines are too small)
Excessive number of bends or fittings or unsuitable bends or fitting
Sustained flow at high pressure
List the five uses for an accumulator?
Shock absorbing
Auxiliary supply
Emergemy supply
Maintain control
Acceleration
Four types of gas accumulators?
Compressed air
Dry nitrogen
Nitrogen
Pure oxygen
What are the two classes of accumulator?
Weight loaded
Gas charged
What are the three most common types of dcv?
Closed, open, tamden
Three methods of applying flow control value?
Meter in
Meter out
Bleed off
When should a counterbalance value be used?
When maintaining a set pressure in part of a circuit
When should A meter out circuit be used?
When a load is pulled downward due to gravity
What are motors rated by?
Rpm’s
What are four types of gas accumulators?
Compressed air
Dry nitrogen
Nitrogen
Pure oxygen
What are three factors which affect flow through an orifice?
Velocity, density , orifice area
What is cracking pressure?
Barely open
Why would you use a temperature gauge?
Monitor for and excessive Heat
What are the 3 types of conductors?
Piping material
tubing material
Flexible hose materials
What is the most common flow control valve?
Meter out
What does an unloading valve do?
Returns pump output back to resviar after desired pressure is met
What does a pressure relief value?
Uses a spring, ball, pottet or piston to release excess system pressure
What are the three main function of a counter balance value?
Support
Control
Safety
What is a Major factor in hydraulic component failure?
Contamination
What is a purpose of a magnetic drain plug?
Attract steel or iron particles
What is the purpose of a strainer ?
Keep large solid objects out of system (think of tufts cove cooler system)
What is nominal filter rating mean ?
Removes most particles
What does absolute filter mean?
All particles removed,
What is bursting pressure?
Wall thickness and the inside diameter of pipe
What determines the bursting pressure in a lines
Wall thickness and inside diameter
What type of pipe is used in hydraulic systems’
Steamless steel
Why is tubing A popular hydraulic conductor
Easily bend and flared
What in the purpose of hose?
Connect parts which move in relation to each other
What does this centre?
Closed
What does this centre show?
Open
What does this centre show?
How is pressure created in a hydraulic system?
Created by resistance to flow
How many inches cubed in imp gal?
277 inches cubed
How many inches cubed in us gals?
231 inch cubed
How do you find pressure?
Force divided by area
How do you find force?
Pressure x area
How do you find area?
Force divided by area
How is force represented? (Units)
Lbs
How is area represent? (Units)
Inches squared
How is pressure shown? (Units)
Psi
What is recommended height on return and section lines?
11/2 to 2 times the pipe diameter
The volume of fluid in the reservoir is normally equal to _____________ the rated pump delivery for one minute
2 to 3 times.
What are flow meters used for?
Monitor the flow in a line and to determine the efficiency of pumps and motors
What are the three main parts of an hose?
Inner tube
Reinforcement
Outer protective cover
