[Hydraulics] Flashcards
How may both rigid and flexible copper tubing be cut?
Tubing cutter or a hacksaw
What is the compressibility of hydraulic oil?
1/2 of 1% at 1,000 psi
Horsepower requirement for the energy medium used to drive the hydraulic pump in the system
Horsepower of prime mover
Resistance of a fluid to flow within itself
Viscosity
List PSI and diameter for:
1) Threaded piping
2) Welded, flanged-connected piping
1) Diameters up to 1 1/4 inches and pressures up to 1,000 psi
2) Exceeding 1 1/4 and 1,000 psi
Valve that is usually manually-operated and used to stop and start the flow of fluid
Stop valve
Types of filters
- Proportional flow - a portion of system flow passes through filter
- Full flow - all system flow passed through filter
- Indicator type - flow filter that tells you when filter is getting dirty
Anything which tends to produce or modify motion
Force (push or pull)
Types of piston pumps
Axial (swash plate) and radial
Swash plate - main shaft is connected to it; also called a tilt box; by varying the angle of the swash plate, we will be able to vary the discharge of the pump
Which type of line is generally used for its resistance to vibration?
Flexible hosing
Troubleshooting rules
- Find out as much about the problem as possible
* Never disassemble a component unless you are sure it is at fault
Pressure reading that does not take into account atmospheric pressure
Pounds per Square Inch Gauge (PSIG)
Perpendicular distance from the fluid level on the reservoir to the pump
Lift
Seven things about preventative maintenance
- Follow PMCS schedule
- DIRT is #1 enemy of a hydraulic system
- Change or clean filters and strainers as required
- Keep the environment clean
- Always filter the fluid before you fill the reservoir
- Visual inspection can be performed
Device in the fluid line used to trap contaminates from the fluid flowing through them
Strainers
1) Condition where entrapped air is pulled out of the fluid and erodes port materials
2) How is it caused?
1) Cavitation
2) Too high of an inlet line or inlet vacuum
Define types and sizes of copper tubing
Type K - heavy wall (hard and soft)
Type L - medium wall (hard and soft)
Type M - thin wall (only hard)
What kind of line is used in hot and cold water distribution systems and hot water heating systems?
Copper tubing
System in which return oil from the actuator is directed to the reservoir to be picked up by the pump and recirculated
Open loop system
Two types of pipe benders
- Internal - used when both ends flared
* External - used when one end flared
Rotary thrust or turning force of a motor, engine, or wrench
Torque
Law that states “Pressure applied to a confined fluid is transmitted undiminished, and in all directions, and acts with equal force on equal areas and at right angles to them.”
Pascal’s Law
What are the two types of tubing used for hydraulic lines?
Seamless and electric-welded
1) The ability or capacity to do work
2) What are its two forms?
1) Energy
2) Potential energy (pressure) and kinetic energy (flow)
Pressure reading that is equal to gauge pressure plus atmospheric pressure
Pounds per Square Inch Absolute (PSIA)
What stores high pressure for future use? Used in hydrostatic systems to develop flow; most common is gas-charged (dry nitrogen)
Accumulator before working on a circuit, make sure all pressure is relieved (hydraulic only)
Types of bourdon tube gauges
- Simplex - designed only for reading pressure
- Duplex - measures two different pressure at the same time and both are reading on the same scale
- Compound - designed to measure pressure and vacuum
- Vacuum - designed to only measure vacuum
1) Simple relief valve
2) Compound relief valve
1) High override pressure (bad)
2) Low override pressure (good)
Force applied to a unit area; resistance to flow
Pressure