02 introduction to pneumatics 1

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Workshop #4

Stennis Space Center

January 7,2006

Introduction to Pneumatics


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Overview

Methods of Power Transmission

Pneumatics Systems

Pneumatics Principles

PartsPneumatic Actuators

Force Principles

Solenoid Valves

Advantages


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Methods of Power TransmissionMethods of Power Transmission

Electrical Motors

Mechanical power transmission elements

Fluid Power

HydraulicsOil, Water, other liquids

PneumaticsAir, other gases


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Electric Motors Motors convert electricalenergy to mechanical

Electric motors used inFirst kit

Chipahua/CIM Motor

Window MotorVan Door Motor

Fisher-Price/Mabuchi

Motor

Globe Motor


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Mechanical Power transmission elements

Gears

Belts

Chains

BearingsCouplings


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Mechanical Power transmission using gears


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Pneumatics SystemsPneumatics Systems


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Pneumatics DefinitionsPneumatics Definitions

Pneumatics is the general term used to describe the

mechanics of gases

Pneumatics, derived from the Greek wordpneumatikos,

meaning coming from the wind

It is the branch of science which treats the mechanical

properties of air and other elastic fluids used to do work
http://www.biocrawler.com/encyclopedia/Greek_languagehttp://www.biocrawler.com/encyclopedia/Greek_language


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Pneumatic Principles

compressor

reservoir tank

solenoid valve

cylinder

hose


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PneumaticsPneumatics

Compressor

Accumulators

Actuators

Source of Air Flow Driven by electric motor

Provides the energy to perform the work

Reservoir tank - Energy Storage Devices

Cylinders convert energy in the compressed air

pressure to linear power. Make things move

Linear

Rotary


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PneumaticsPneumatics

Connectors

tubing

Pressure

regulators

Valves2-way

3-way

4-way

Plumbing- connectors -flexible tube

Pressure control -controls the force of

the actuator

Control direction of flow


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Compressor Thomas industries

12 volt system

Generates

pressure of 120 psi

Compact

Vibration isolators


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Relief Valveon Compressor

Protects compressor

Pressure SwitchSignals the controller

to start or stop the

compressor

Additional Compressor Components

Pressure In

NC NO

Common


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Accumulators

Pneumatic tank

Up to twoStore compressed air at 120 psi

Helps keep the pressure constant

Smooth out the pressure fluctuation


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Cylinders


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Rotary Actuator


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Fittings and Plugs


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Flow Controls

Regulate flow of air into and out

of a cylinder

Used to control speed of apneumatic cylinder

If used, attach directly to

cylinder (only one end needed)


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Exhaust Valve

Use to release

pressure


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FittingsFittingsConnection and DisconnectionConnection and Disconnection


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RegulatorsRegulators

Regulators Control Pressure

Relieving type in the FIRST kit 2 are included

The use of Regulators assuresmaximum efficiency

Allows air from reservoirs toflow to rest of pneumaticsystem

Limits pressure in valves,

cylinders to60 psi


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Solenoid Electric Valves


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Pneumatic ActuatorsPneumatic Actuators applies force or creates

motion through the use of a pneumatic system


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Pneumatic ActuatorsUse Pressurized Air to achieve motion

Provide power and speed to any actuation

system.

Variety of Actuation mechanisms available

Arms

Grippers

Shifters


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Arms


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Grippers


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Shifters


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ActuatorsActuatorsConstruction & OperationConstruction & Operation

Basic Construction

Operation


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Compressed Air

is routed by the valve to extend orretract the cylinder

ActuatorsActuators


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ActuatorsActuators

Most Common types of Linear ActuatorsDouble Acting Single Ended Double Ended

Single Acting

Spring Return

All containCylinder Barrel Piston RodSealsSpring if used


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Facts about PneumaticsFacts about Pneumatics

Pressure Units of measure

Lbs per in2 or Force per unit area

Absolute Pressure 14.7 psia at sea level

Gauge Pressure measured relative to ambient

Flow

cfm cubic foot (feet) per minute Volume per unit time

Scfm Standard cubic foot (feet) per minute


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Force Principles

Gauge Pressure works against

each square inch of pistonsurface

The greater the square inch surface of the fluid, the

less internal pressure will be developed.


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ActuatorsActuatorsDifferential AreasDifferential Areas

Force

Consideration Consider the effective areaon which the pressure acts On single ended cylinders

there is a differential Dont forget friction


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Cylinders

Force = Pressure Area

2 diameter piston

Area = 3.14 12 = 3.14 in2

Pressure = 60 psi

3.14 in2 60 psi = 188 lbs

Force while extending

greater than while retracting

Main decisions: Length and diameter

Diameter based on required force

Larger diameter: more force, but more air


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Cylinder maximum force

Dia Cylinder

- 10 Throw 26 lb max force

1-1/2 Dia Cylinder

-24 Throw 106 lb max force

2 Dia Cylinder-24 Throw 188 lb max force


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Cylinder Forces

Force Applied = Pressure *

Cross Sectional Area

Pressure applied on a flat plate,

causes a force!

The bigger the plate, or the higher

the pressure, the greater the force.

Less force in than out.

This is due to a reduced crosssection (caused by the rod being in

the way!)


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1.5 Bore Cylinder

Retracted Length = 4.38 + Stroke + .25 + 1.31 = 5.94 + Stroke

Base Dimension = 4.38 + Stroke Length = ? +

Locking Nut = .25 +

Clevis Dimension = 1.31

Extended Length = 5.94 + (2 x Stroke Length)


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Single Solenoid Valve

When energized, cylinder

goes to one state

When de-energized, cylinderalways returns to rest state

When power is cut at the end

of the match, cylinder willreturn to rest state

Each valve powered by one

relay module (only in


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Double Solenoid Valves

One solenoid pulsed to move cylinder one way,

other solenoid pulsed to move cylinder the other

wayResults unpredictable if both pulsed

Valve will stay in either state when neither

solenoid energizedCan use one relay for each solenoid or one

relay and two diodes


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4-way Valves in your kit4-way Valves in your kit

Double Solenoid (detented)

SMC

Single Solenoid (spring offset)SMC


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Single Solenoid (spring offset)Festo


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Single SolenoidPoppet (Spring Offset)


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4-way 5-port Valves4-way 5-port ValvesDirectional ControlDirectional Control

Passage A Passage B

Spool

Valve Body

Pressure

Passage

Exhaust

Passage

SolenoidSpring


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Why use Pneumatics in 2006?Why use Pneumatics in 2006?

The AdvantagesThe Advantages

Complete kit:

All the parts required to

build an operating systemWeight:

equal or lighter than

comparable alternatives

Adjustable Force:

Different bore cylinders

change the available

forceand

By adjusting the applied

pressure you can

instantly adjust the

force


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Durableno burned up motors

stall with no damage

Strongfrom 9 lbs to 180 lbs easily adjustable

Custom cylindersin just a few days by

UPS

Last minute additionsadd a valve or a cylinder

quickly




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Multiple cylinders use

same compressor

Strong

from 9 lbs to 180 lbs

easily adjustable

Custom cylinders

in just a few days by UPS

Last minute additionsadd a valve or a cylinder

quickly


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Why do we design with pneumatics?Simple Pneumatic Cylindersare force vectors.

Each cylinder represents aforce, which will be applied over

a certain distance.Most pneumatic design involvesarms or linkages of some type.

Know principles of leverage andtorque!


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SafetySafety

always be considered

Relieve the pressure before working on the system

Be aware of pinch pointsAvoid side-loading increases friction and wear

Avoid getting grit or metal shavings on the rod or in

the cylinderUse flow controls for safety

Compressed Air is like a coiled spring

Safety MUST

I t ti Li k


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Interesting LinksFluid Power Educational

Foundation

www.fpef.org

Nason Corporationwww.nasonptc.com

Bosch Rexrothwww.bosch-

rexroth.comwww.boschrexroth.com

Bimba Manufacturingwww.bimba.com

Lord Corpwww.lordmpd.com

Fluid Power Dist. Assnwww.fpda.org

Clippard Instrument Lab.

www.clippard.com Monnier, Inc.www.monnier.com Fluid Power Societywww.ifps.org

Wikawww.ewika.com/WikaSite/GlobalSites.aspx

Norgrenwww.norgren.com

Natl Fluid Power Assnwww.nfpa.com

Festowww.festo.com

Parkerwww.parker.com

SMC Pneumaticswww.smcusa.com


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Q/A

Any Questions?

About this lecture?

About Pneumatics?About Design?

About FIRST?About the Game?

02 introduction to pneumatics 1

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