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

[Hydraulics] Flashcards by Kade Miller

How may both rigid and flexible copper tubing be cut?

Tubing cutter or a hacksaw

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What is the compressibility of hydraulic oil?

1/2 of 1% at 1,000 psi

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Horsepower requirement for the energy medium used to drive the hydraulic pump in the system

Horsepower of prime mover

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Resistance of a fluid to flow within itself

Viscosity

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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

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Valve that is usually manually-operated and used to stop and start the flow of fluid

Stop valve

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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

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Anything which tends to produce or modify motion

Force (push or pull)

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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

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Which type of line is generally used for its resistance to vibration?

Flexible hosing

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Troubleshooting rules

Find out as much about the problem as possible

* Never disassemble a component unless you are sure it is at fault

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Pressure reading that does not take into account atmospheric pressure

Pounds per Square Inch Gauge (PSIG)

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Perpendicular distance from the fluid level on the reservoir to the pump

Lift

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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

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Device in the fluid line used to trap contaminates from the fluid flowing through them

Strainers

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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

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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)

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What kind of line is used in hot and cold water distribution systems and hot water heating systems?

Copper tubing

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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

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Two types of pipe benders

Internal - used when both ends flared

* External - used when one end flared

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Rotary thrust or turning force of a motor, engine, or wrench

Torque

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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

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What are the two types of tubing used for hydraulic lines?

Seamless and electric-welded

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1) The ability or capacity to do work

2) What are its two forms?

1) Energy

2) Potential energy (pressure) and kinetic energy (flow)

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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

What is gained in force is..

lost in distance

Condition where air is entering the inlet side of a pump

Aeration

Perpendicular distance from the pump discharge to the highest point in the discharge line

Head

Law that states “Energy can neither be created nor destroyed”

Law of energy conservation

How are strainers and filters rated?

* Strainers - rated in mesh | * Filters - rated in microns

What are the three pressures associated with pressure relief valves?

Cracking, full flow, and override pressure

List type of linear actuators

Single-acting Double-acting • Differential • Non-differential

Types of vane pumps

Unbalanced, unbalanced variable displacement, and balanced

Converts mechanical energy to hydraulic energy

Hydraulic pump

Basic requirements of circulatory system

* Lines * Terminal fittings * Supports * Lines with smooth interiors * Kept clean from all sources of contamination

Valve used for quick opening and closing

* Plug valve | * Butterfly valve *never paint*

Three major groups for troubleshooting

• Energy group - prime movers - electrical source - internal combustion engines • Mechanical group - check couplings for looseness or damage - check for binding linkages • Fluid group - LEAKS are the most common source of trouble - internal leaks cause losses in efficiency - external leaks are fire and safety hazards

Amount of space occupied in three dimensions

Volume

Temperature at which a fluid’s vapors will ignite

Flashpoint

Valve used to protect the system from overloading

Relief valve

Types of hydraulic fluids

* Petroleum base | * Synthetic fire resistant

Measurement of a bounded region or plane, or the surface of a solid

Area

System in which the fluid discharged from the actuator is recirculated at low pressure back to the pump inlet instead of being returned to the tank

Closed loop system

What are the three types of lines in liquid-powered systems?

Pipes, tubing, and flexible hoses

What are the two types of fittings?

* Solder - used with either rigid or flexible copper tubing * Compression (flared) - used only with flexible copper tubing; principle use is in air piping and fuel-oil lines for their vibration resistance

Device which synchronizes two identical cylinders’ speed regardless of load balance between them

Flow divider

What is the greatest aid to troubleshooting?

Confidence in knowing your system

What are the normal and maximum operating percentages?

* Maximum normal is 50% | * Maximum is 75%

The rate of doing work or expending energy

Power

Any force which stops or retards the movement of a body

Resistance

Exerting a force through a definite distance

Work

Volume of liquid that can pass through a pump, motor, or cylinder in one revolution

Displacement

Types of gear pumps

External gear: spur, helical, and herringbone Internal gear: gerotor (ring gear)

Positive displacement pump whose output cannot be made variable

Fixed displacement pump

How are pumps rated?

* Flow in GPM * Maximum Operating Pressure (MOP) * Given drive speed

Valve with long tapered needle and seat

Needle valve *never over-tighten*

Converts hydraulic energy to mechanical energy

Actuator

Pump that delivers a set quantity of fluid for each revolution or stroke

Positive displacement pump (hydrostatic)

Positive displacement pump whose output can be changed to suit operating conditions

Variable displacement pumps

Where are the strainers and filters in relation to the pumps?

Strainers are before pumps and filters are after pumps

Device in the fluid line used to trap fine particles and prevent them from remaining in the system

Filter

Device that is used to create flow by using an outside source of power (prime mover)

Pump

Amount of liquid flow that a pump will produce in a given time

Delivery

Function of confined fluids

``` Transmit power (liquid pressure) Multiply force (liquid pressure) Modify motion (liquid flow) ```

Describe the two types of flow

Laminar: a smooth, parallel flow path with fluid particles traveling in a straight line, undisturbed Turbulent: Upset, erratic flow path with fluid particles colliding with each other

Valve used for straight lines of flow; has either rising stem or non-rising stem, and is difficult to repair

Gate valve

List the two mechanical and soldering techniques

* Single flare - 45 degree flare on end of tubing | * Double flare - 45 degree flare on end of tubing which is doubled over

Lightweight unit you can use to check or troubleshoot a hydraulic-powered system on the job or in a maintenance shop

Portable hydraulic-circuit tester

Valve used to direct the flow of fluid to a specific point or component

Directional control valve