Hydraulic is in what unit?
Cubic Feet per Minute. CFM’s
Cylinder Creep is what?
Actuator can still move even when system is off
What must you do to avoid cylinder creep?
-De-energize
-Add Blocks
How should you un bolt a flange (where should you be)?
-Be on opposite side of what you are unbolting
Do filters get better over time? What is the downside?
Yes. Dirt/Debris acts like a filter too. But the you lose flow
At what pressure does a pin hole cause damage and injury?
100psi ~7bar
500-1000psi (fluid forced under skin)
2,000-3,000+psi (deep tissue damage, amputation)
What are some advantages of Hydraulics?
-High power in small package
-Minimal power loss
-speed and force control
What are disadvantages of Hydraulics?
-Expensive
-Heavy
-Safety Hazard
-Leaks
-Flammability
What is 1 bar equivalent to in osi?
1 bar = 14.5 psi
What does psi stand for and what is it measuring?
-Pounds per square inch
-Psi only calculates the weight of what’s above it
Ex. Box of water and a 1”pipe at the bottom and in the middle of it. The psi is the weight of water only above the the 1” pipe opening. Not the entire weight of volume of water in the cube
What is the Force Triangle?
Traingle:
F = Force (on top)
P = Pressure (L side)
A = (R side)
What can Flow be expressed by (2 types of factors)
-Speed/Velocity
-Flow Rate
What is Speed/Velocity in Flow?
-Distance fluid travels in a period of time
-Feet per Minute
-Feet per Second
What is Flow Rate in Flow?
-is the volume of fluid passing a given point in a given period of time
What is the Unit of measurement for Flow Rate?
Unit of measurement:
-Gallons per Minute
-Cubic Inch per minute
-Litres per minute
What is the Unit of measurement for Speed/Velocity?
-Feet/Meters per Minute
-Feet/Meters per Second
What is the Flow Triangle?
What is a Regenerative Circuit?
A way to produce faster rod extension
How does a Regenerative Circuit work?
By grabbing oil from the rod end and redirecting it to the head end of cylinder
Give an example of how a Regenerative Circuit works in a Cylinder
If you want a Cylinder to Extend, connect a line directly from the Rod end to the Piston end.
When Piston fills up extend the Cylinder, the fluid from the Rod side will drain into the same line that feeds the Piston end.
This will cause more fluid to rush in compared to when it was just a single hydraulic line
HYDRAULIC CONTROL VALVES
What is a Safety / Pressure Relief Valve?
-Purpose: Protects the system from too much pressure
-Where: Right after pump
-Action: Diverts fluid back to the tank
Explain what a Pressure Reducing Valve
-Purpose: Limits the pressure going to part of the circuit
-Where: Before the part of the circuit you want less force
-Action: Reduces pressure so cylinder or motor doesn’t overload
What is a Pilot-Operated Relief Valve
-Purpose: Relieves high pressure in large or high-flow systems
-How: Small pilot line senses pressure → opens main relief valve
-Benefit: Can handle big pumps without opening too early
