Unit 3 Lecture 1-2 Linear and Angular Measurement.pdf

lecture slides

1. Linear and Angular
Measurement
1
Unit 1 Lecture 1-4

2. 2
Unit 3 Lecture 1-2
Linear and Angular Measurement
❑DefinitionofMetrology
❑DesignofLinearMeasurementInstruments
❑LinearandAngularMeasurement:
1.Linearmeasuringinstruments:Vernier,micrometerand
intervalmeasurement-Slipgaugesandclassification.Interferometer,
opticalflatsandlimitgaugesComparators:Mechanical,pneumaticand
electricaltypes,applications.
2.Angularmeasurements:Sinebar,opticalbevelprotractor,Taper
measurements

3. Definition of Metrology
3
❑DefinitionofStandards:Astandardisdefinedas“somethingthat
issetupandestablishedbyanauthorityasruleofthemeasureof
quantity,weight,extent,valueorquality”.
❑Metrologyisthenamegiventothescienceofpuremeasurement.
Butinengineeringpurposes,EngineeringMetrologyisrestrictedto
measurementsoflengthandanglesandotherqualitieswhichare
expressedinlinearorangularterms.

4. 4
❑DimensionalmetrologyisthatbranchofMetrologywhichdealswith
measurementof“dimensions“ofapartorworkpiece(lengths,angles,
etc.)
❑Dimensionalmeasurementsattherequiredlevelofaccuracyarethe
essentiallinkbetweenthedesigners’intentandadeliveredproduct.
❑Mostpeople’sfirstcontactwithlinearmeasurementiswithasteelruleora
tapemeasure.
❑Measurementsystemsaremainlyusedinindustriesforqualitycontrol.
Oftenwidelyusingmeasurementsare
1.LinearMeasurement
2.Angularmeasurement
Definition of Metrology

5. 5
❑TheLinearMeasurementincludesmeasurementsoflength,
diameters,heightsandthickness
❑TheAngularmeasurementincludesthemeasurementofanglesor
tapers
❑Averycommonmeasurementisthatofdimensions,i.e.,length,
width,heightofanobject.Dimensionsofthemeasuring
instrumentsareclassifiedasfollows
▪Low resolution devices (up to 0.25mm)
▪Medium resolution devices (up to 0.0025mm)
▪High resolution devices (less than microns)
Definition of Metrology

6. 6
Definition of Metrology
Steel rule
Steel rule with assistance of
◦Calipers
◦Dividers &
◦Surface gauges
Thickness gauges
Low resolution devices

7. 7
Definition of Metrology
Micrometer
Micrometer with assistance of
◦Telescoping
◦Extendable ball gauges
Vernier calipers
Dial indicators
Microscope
Medium resolution devices

8. 8
Definition of Metrology
High resolution devices
Gauge blocks
Gauge block with assistance of
◦Mechanical comparator
◦Electronic comparator
◦Pneumatic comparator
◦Optical flats

9. 9
❑However,today’sengineerhasachoiceofwiderangeof
instrumentstochoosefromrightfrompurelymechanically
operatedinstrumentstodigitalelectronicsinstruments.
❑Onehastoonlyconsiderthenatureofapplicationandcostof
measurementtodecidewhichinstrumentisthebestforan
application.
❑Thischaptercoversabroadrangeoflinearmeasurement
instrumentsfromasimplesteelruleuptodigitalcalipersand
micrometer
Definition of Metrology

10. Design of Linear
Measurement Instruments
❑Themeasuringaccuracyoflinegraduatedinstrumentsdepends
ontheoriginalaccuracyoflinegraduations.Excessivethickness
orpoordefinitionofgraduatedlinesaffecttheaccuracyof
readingscapturedfromtheinstrument.
❑Anyinstrumentincorporatingascaleisasuspectunlessitis
providedcompensationagainstwear.
❑Attachmentscanenhancetheversatilityofinstruments.
However,everyattachmentusedalongwithaninstrument,
unlessproperlydeployed,maycontributetoaccumulatederror.
Wearandtearofattachmentscanalsocontributetoerrors.
10

11. Design of Linear
Measurement Instruments
❑Instrumentssuchascalipersdependonthefeeloftheuserfortheir
precision.Goodqualityoftheinstrumentpromotesreliability,but
ultimatelyskilloftheuserensuresaccuracy.
❑Theprincipleofalignmentstatesthatthelineofmeasurementand
thelineofdimensionbeingmeasuredshouldbecoincident.This
principleisfundamentaltogooddesignandensuresaccuracyand
reliabilityofmeasurement.
❑Dialversionsofinstrumentsaddconvenienceinreading.
Electronicversionsprovidedigitalreadoutswhichareeveneasier
toread.
11

12. Design of Linear
Measurement Instruments
❑Oneimportantelementofreliabilityofaninstrumentisits
readability.
❑Ifcostisnotanissue,digitalinstrumentsmaybepreferred.The
chiefadvantageofelectronicmethodistheeaseof‘signal
processing’.Thereadingsmaybeexpresseddirectlyintherequired
formwithoutadditionalarithmetic.Thereadingscanbestoredona
memorydeviceforfurtheruseandanalysis.
❑Whenever,contactbetweentheinstrumentandsurfaceofthejob
beingmeasuredisinevitable,contactforceshouldbeoptimumto
avoiddistortion.Thedesignercannotleavethefateofthe
instrumentontheskilloftheuseralone.
12

13. Linear and Angular Measurement
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Measuringtoolsandinstruments
Direct (contact) measurement
(e.g. micrometer or caliper)
Indirect(non-contact)measurement
(advancedmethodssuchasoptical,
ultrasonic,laser,etc.)
▪Calipers
▪Gauges and Gauge Blocks
▪Sine Bar
▪Special-purpose tools
▪Rules
▪VernierCalipers
▪VernierGauges
▪Micrometers
▪Protractors
▪DialIndicators
Graduated
(either linear or angular
graduations incorporated into
measuring system of the tool)
Non-graduated
(gauges or adjustable
tools which compare
the measurements)

14. Surface Plate
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15. Surface Plate
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16. Surface Plate
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17. V‐ Blocks
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V-Block:
❑Checkingroundnessofcylindrical
workpiece
❑Marking centers accurately
❑90°angle
❑Types:
i.Depending on accuracy
▪Grade A
▪Grade B
ii.Depending on design
▪One vee
▪Two vee

18. V‐ Blocks
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19. V‐ Blocks
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20. Linear and Angular Measurement
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GraduatedLinearMeasurement-Rules

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GraduatedLinearMeasurement-Rules

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GraduatedLinearMeasurement-Rules

23. Linear and Angular Measurement
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GraduatedLinearMeasurement-Rules

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GraduatedLinearMeasurement-Rules
Imperialsteelrulewithvariouslengths
havinggraduationsoneachside
Samerulewithrelativelylarger
graduations
Metricsteelrulewithvariouslengths
havinggraduationsoneachside
How to read a rule:
A = 12 mm (12
th
graduation)
B = 22 mm (22
nd
graduation)
C=31.5mm(between
D=40.5mm(between
31st
40th
and 32nd)
and 41st)
resolution?

25. Linear and Angular Measurement
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GraduatedLinearMeasurement-Scaled Instruments

26. Linear and Angular Measurement
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GraduatedLinearMeasurement-Depth Gauge

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GraduatedLinearMeasurement-Combination Set

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GraduatedLinearMeasurement-Combination Set

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GraduatedLinearMeasurement-Vernier Instruments

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GraduatedLinearMeasurement-Vernier Instruments
❑Twoscales:Main&
Vernier
❑Slightdifferencein
divisionsisused
enhance the
accuracy
❑Threeelements:
Beam,FixedJaw&
SlidingJaw
❑Errors in
measurements
❑DigitalCaliper

31. Linear and Angular Measurement
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GraduatedLinearMeasurement-Vernier Instruments

32. Linear and Angular Measurement
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GraduatedLinearMeasurement-Vernier Instruments
Components of vernier calipers are
❑Main scale
❑Vernier scale
❑Fixed jaw
❑Movable jaw
Types of vernier calipers
1)Type A vernier caliper
2)Type B vernier caliper
3)Type C vernier caliper

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GraduatedLinearMeasurement-Vernier Caliper

34. Linear and Angular Measurement
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GraduatedLinearMeasurement-Vernier Caliper
Guidelines for the use of Vernier Caliper

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GraduatedLinearMeasurement-Vernier Caliper
Guidelines for the use of Vernier Caliper

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GraduatedLinearMeasurement-Vernier Caliper

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GraduatedLinearMeasurement-Vernier Caliper

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GraduatedLinearMeasurement-Vernier Caliper
❑Verniercalipersareavailableinsizeof150mm,225mm,900mmand1200mm.
❑Theselectionofthesizedependsonthemeasurementstobetaken.
❑Verniercalipersareprecisioninstruments,andextremecareshouldbetaken
whilehandingthem.
Verrier caliper with 0.02 mm Least Count is generally used in work shop.
In this Vernier caliper main scale division (49mm) are divided in to 50 equal part in the Vernier scale.
i.e. 1 main scale division =1 mm (MSD)
1. Vernier scale division =49\50 mm
(VSD)
Least count is : 1mm –49\50 =1\50 mm
The difference between 1 MSD and 1 VSD = 0.02mm

39. Linear and Angular Measurement
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GraduatedLinearMeasurement-Vernier Caliper
Main scale reading =35mm
The vernier division coinciding with the main scale is the 20th division.
Value=20 multiplied by 0.02=0.40mm.
Total reading is 35mm+0.40= 35.40mm
35.40 mm
Example

40. Linear and Angular Measurement
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GraduatedLinearMeasurement-Vernier Caliper
Dial Caliper

41. Linear and Angular Measurement
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GraduatedLinearMeasurement-Vernier Caliper
Electronic Digital Caliper

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GraduatedLinearMeasurement-Vernier Caliper
Electronic Digital Caliper

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GraduatedLinearMeasurement-Vernier Depth Gauge

44. Linear and Angular Measurement
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GraduatedLinearMeasurement-Vernier Height Gauge
❑KindofVernierCaliper
❑Haveaccessoriesto
makesuitablefor
heightmeasurement

45. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments

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GraduatedLinearMeasurement-Micrometer Instruments
Conformity to ABBE’s Law

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GraduatedLinearMeasurement-Micrometer Instruments
Conformity to ABBE’s Law

48. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
Parts of Micrometer
▪Frame
▪Anvil and spindle
▪Screwed spindle
▪Graduated sleeve or barrel
▪Ratchet or friction stop
▪Spindle clamp

49. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments

50. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
V-anvilMicrometer(measuringodd
flutedtaps,millingcutters,reamers,
andcheckingoutofroundness)Dial-indicatingMicrometer
Direct-reading
Micrometer
ScrewThreadMicrometer(measuring
pitchdiameterofscrewthreads)

51. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
Outside Micrometers

52. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
Outside Micrometers

53. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
Outside Micrometers

54. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
Types of Micrometers

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GraduatedLinearMeasurement-Micrometer Instruments
Types of Micrometers

56. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
Types of Micrometers
MetricMicrometer
SLEEVE (BARREL) READING
Metric Vernier
Micrometer
THIMBLEREADINGVERNIERREADING

57. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
Vernier Micrometer

58. Linear and Angular Measurement
58
GraduatedLinearMeasurement-Micrometer Instruments
Vernier Micrometer

59. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments

60. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments

61. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
Inside Micrometer Caliper

62. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
Inside Micrometer Caliper
StandardInsideMicrometers DigitalInsideMicrometers

63. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments
Inside Micrometer Caliper

64. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments

65. Linear and Angular Measurement
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GraduatedLinearMeasurement-Micrometer Instruments

66. Linear and Angular Measurement
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GraduatedLinearMeasurement-Pin Gauge

67. Linear and Angular Measurement
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GraduatedLinearMeasurement-Pivotal Stylus & Autocollimator

68. Linear and Angular Measurement
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GraduatedLinearMeasurement-Pivotal Stylus & Autocollimator
Measuring the diameter of small bore by Pivoted Stylus

69. Linear and Angular Measurement
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Non-GraduatedLinearMeasurement-Calipers
Calipers:
➢Consists of two legs
➢Accessory to scale
➢Reducesightingerrors
andincreaseaccuracy
➢Two types:
ii.Firm Joint type
✓Outside
✓Inside
ii.Spring type
✓Outside
✓Inside
✓Transfer
✓Hermaphrodite

70. Linear and Angular Measurement
70
Non-GraduatedLinearMeasurement-Calipers
➢Standard calipers have a fine adjustment screw and a quick-adjusting spring nut.
➢Accuracy obtained with these tools depends mostly on the inherent skill of users.
➢The measurements are carefully transferred to a graduated measuring tool.
Caliper for inside
measurement
Caliper for outside
measurement
Caliper used
as a divider

71. Linear and Angular Measurement
71
Non-GraduatedLinearMeasurement-Calipers
❑Therearemanyjobswhosedimensionscannotbemeasured
accuratelywithasteelrulealone.Atypicalcaseinpointisajob
withcircularcross‐section.
❑Anattempttotakemeasurementusingasteelrulealonewillleadto
error,sincethesteelrulecannotbepositioneddiametricallyacross
thejobwiththerequireddegreeofaccuracy.
❑Calipersaretheoriginaltransferinstrumenttotransfersuch
measurementsontoarule.Theycaneasilycapturethediameterof
ajob,whichcanbemanuallyidentifiedasthemaximumdistance
betweenthelegsofthecaliperthatcanjustslideoverthediameter
ofthejob.
❑Eventhoughcalipersarehardlyusedinproductioninspection,they
arewidelyusedintoolroomandrelatedwork.

72. Linear and Angular Measurement
72
Non-GraduatedLinearMeasurement-Calipers
❑Calipersdophysicallyduplicatetheseparationbetweenthereference
pointandmeasuredpointofanydimensionwithintheirrange.Theydo
thejoboftransferringadimensiononly,butnotmeasuringinstruments
ontheirown.
❑Calipersareavailableinvarioustypesandsizes.Twomajortypesarethe
firmjointcaliperandthespringcaliper.
❑Firmjoint,asthenameitselfsuggests,canholdthepositionoftwolegs
openedouttoaparticulardegreeunlessmovedbycertainforce.Thisis
possiblebecauseofhigherfrictioninthejointformedbetweenthetwo
legsofthecaliper.Alocknutisneededtolockthecaliperinaparticular
position.
❑Ontheotherhand,aspringcalipercanholdaparticularpositionthanksto
thespringpressureactingagainstanadjustingnut.Thispermitsvery
carefulcontrolandnolockisneeded..

73. Linear and Angular Measurement
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Non-GraduatedLinearMeasurement-Calipers

74. Linear and Angular Measurement
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Non-GraduatedLinearMeasurement-SpecialPurposeGauges
ScrewPitchGauges(consistingofametalcase
containingmanyseparateleaves.Eachleafhasteeth
correspondingtoadefinitepitch.Bymatchingthe
teethwiththethreadonwork,thecorrectpitchcanbe
readdirectlyfromtheleaf)
TapandDrillGauges(consistingofaflat
rectangularsteelplatewithholesaccurately
drilledandidentifiedaccordingtotheirsize)
RadiusGauges(availableasindividualleavesandpeachleafismarkedwith
itsradius.Theyaredesignedtocheckbothconvexandconcaveradii)
➢Engineer'staper,wire&thickness
gauge:
❑Consistsofleavesfor
❑Tapermeasurement
❑Wirediametermeasurement
❑Thicknessofsmallgaps
➢PitchScrewGauge:
❑Containsmultipleleaves
❑Matchesteethontheleaves
withteethonwork

75. Linear and Angular Measurement
75
Non-GraduatedLinearMeasurement-SpecialPurposeGauges
ScrewPitchGauges(consistingofametalcasecontainingmanyseparate
leaves.Eachleafhasteethcorrespondingtoadefinitepitch.Bymatchingthe
teethwiththethreadonwork,thecorrectpitchcanbereaddirectlyfromthe
leaf)
TapandDrillGauges(consistingofaflatrectangular
steelplatewithholesaccuratelydrilledandidentified
accordingtotheirsize)
Radius Gauges (available as individual leaves and each
leaf is marked with its radius. They are designed to check
both convex and concave radii)

76. Linear and Angular Measurement
76
Non-GraduatedLinearMeasurement-Slip Gauge

77. Linear and Angular Measurement
77
Non-GraduatedLinearMeasurement-Rectangular Gauge Blocks
Slip Gauge Box
Slipgaugesarerectangular
blocksofsteelhavingacross-
sectionofabout30by10mm
Normalset
Range Step Pieces
1.001 to
1.009
0.001 9
1.01 to 1.09 0.01 9
1.1 to 1.9 0.1 9
1 to 9 1 9
10 to 90 10 9
Total 45

78. Linear and Angular Measurement
78
Non-GraduatedLinearMeasurement-Rectangular Gauge Blocks
Slip Gauge Box-Special Set
Range Step Pieces
1.001 to 1.009 0.001 9
1.01 to 1.49 0.01 49
1.5 to 9.5 0.5 19
10 to 90 10 9
Total 86
Classification
▪AA slip gauges
▪A slip gauges and
▪B slip gauges
1.AA slip gauges
Master slip gauges
Accurate to plus or minus two microns per meter
2.A slip gauges
Reference purpose
Type A is guaranteed accurate up to plus or minus four microns per
meter
3.B slip gauges
Working slip gauges
Type 'B' for plus or minus eight microns per meter

79. Linear and Angular Measurement
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AngularMeasurement

80. Linear and Angular Measurement
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AngularMeasurement–Sine Bars

81. Linear and Angular Measurement
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AngularMeasurement–Sine Bars

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AngularMeasurement–Sine Bars

83. Linear and Angular Measurement
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AngularMeasurement–Sine Bars

84. Linear and Angular Measurement
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AngularMeasurement–Sine Bars

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AngularMeasurement–Sine Bars

86. Linear and Angular Measurement
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AngularMeasurement–Sine Bars

87. Linear and Angular Measurement
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AngularMeasurement–Sine Bars

88. Linear and Angular Measurement
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AngularMeasurement–Sine Bars
LimitationsofSineBars:Thesinebarsinherentlybecome
increasinglyimpracticalandinaccurateastheangleexceeds
45°becauseoffollowingreasons:
▪Thesinebarisphysicallyclumsytoholdinposition.
▪Thebodyofthesinebarobstructsthegaugeblockstack,
evenifrelieved.
▪Slighterrorsofthesinebarcauselargeangularerrors.
▪Longgaugestacksarenotnearlyasaccurateasshorter
gaugeblocks.
▪Temperaturevariationbecomesmorecritical.
▪Adifferenceindeformationoccursatthepointofroller
contacttothesupportsurfaceandtothegaugeblocks
▪Thesizeofgauges,instrumentsorpartsthatasinebar
caninspectislimited,sinceitisnotdesignedtosupport
largeorheavyobjects.

89. Linear and Angular Measurement
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AngularMeasurement–Rollers

90. Linear and Angular Measurement
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AngularMeasurement–Rollers

91. Linear and Angular Measurement
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AngularMeasurement–Rollers

92. Linear and Angular Measurement
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AngularMeasurement–Rollers

93. Linear and Angular Measurement
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AngularMeasurement–Sprit Level

94. Linear and Angular Measurement
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AngularMeasurement–Sprit Level
❑Characteristicelementofalevel
❑Sensitivity:expressedastheangleoftiltinsecondsfor
whichbubblewillmovebyonedivisiononthetube
❑Sensitivity=Angleinseconds/1divisionoftube
❑Constantofspritlevel:changeintilt,expressedin
mm/m
❑Accuracyoflevel:baseshouldbeflatwithinprescribed
limits
❑Errors:duetoerrorinthevial,curvaturebeingnon-
uniform,scalepositionedincorrectlyandtemperature
variations

95. Linear and Angular Measurement
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AngularMeasurement–Angles Gauges

96. Linear and Angular Measurement
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AngularMeasurement–Angles Gauges

97. Linear and Angular Measurement
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AngularMeasurement–Protractor

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AngularMeasurement–UniversalBevelProtractor

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AngularMeasurement–UniversalBevelProtractor

100. Linear and Angular Measurement
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AngularMeasurement–UniversalBevelProtractor

101. Linear and Angular Measurement
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AngularMeasurement–UniversalBevelProtractor

102. Linear and Angular Measurement
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AngularMeasurement–UniversalBevelProtractor

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AngularMeasurement–UniversalBevelProtractor

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AngularMeasurement–OpticalBevelProtractor

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AngularMeasurement–OpticalInstruments

106. Linear and Angular Measurement
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AngularMeasurement–OpticalInstruments
Autocollimator
❑Infinitytelescopeandcollimatorcombinedinto
one
❑Anopticalinstrumentusedforsmallangular
differences
❑Providesverysensitiveandaccurateapproach
Application
▪Measurementofstraightnessandflatness
▪Preciseangularindexing
▪Assessmentofsquareness
▪Parallelismofcomponents

107. Linear and Angular Measurement
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AngularMeasurement–OpticalInstruments

108. Linear and Angular Measurement
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AngularMeasurement–OpticalInstruments
Autocollimator

109. Linear and Angular Measurement
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AngularMeasurement–OpticalInstruments

110. Linear and Angular Measurement
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AngularMeasurement–OpticalInstruments
Autocollimator

111. Linear and Angular Measurement
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AngularMeasurement–OpticalInstruments

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AngularMeasurement–OpticalInstruments

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AngularMeasurement–OpticalInstruments

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AngularMeasurement–OpticalInstruments

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AngularMeasurement–OpticalInstruments

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AngularMeasurement–OpticalInstruments

117. Linear and Angular Measurement
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Comparators
1)Mechanical comparators
2)Electrical comparators
3)Optical comparators
4)Pneumatic comparators

118. Linear and Angular Measurement
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Comparators –Mechanical comparators
❑Itisaprecisioninstrumentemployedtocomparethedimensionofagiven
componentwithaworkingstandard
❑Itdoesnotmeasuretheactualdimensionbutindicateshowmuchitdiffersfrom
thebasicdimension

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Comparators –
Mechanical comparators

120. Linear and Angular Measurement
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Comparators –Electrical comparators

121. Linear and Angular Measurement
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Comparators –
Electrical comparators
❑Thesecomparatorsdependonthe
principleofbalancingthe
Wheatstonebridge,(R
1/R
2)=
(R
3/R
4)applicableforonlyto
directcurrentobtainedfroma
battery.

122. Linear and Angular Measurement
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Comparators –Electronic Comparators

123. Linear and Angular Measurement
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Comparators –Electronic Comparators

124. Linear and Angular Measurement
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Comparators –Optical Comparators

125. Linear and Angular Measurement
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Comparators –Optical Comparators

126. Linear and Angular Measurement
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Comparators –Pneumatic Comparators
❑InPneumaticcomparatorsairisusedasameansof
magnificationandhencetheyuseprincipleofairjet.
❑AchamberisfittedwithcontrolorificeCanda
gaugingorificeGthroughwhichairflowsfroma
supplyataconstantpressureP
1.
❑IfthesizeofthecontrolorificeCremainsconstant,
anyvariationinsizeofGwillcausealterationof
pressureP
2inthechamber.
❑Thisvariationismeasuredbyasuitablepressure
gaugegraduatedtoreadinlinearunits.

127. Linear and Angular Measurement
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Comparators –Pneumatic Comparators
❑Basedonthephysicalphenomenon,
pneumaticcomparatorsareclassifiedas;(a)
Floworvelocitytype(b)Backpressuretype
❑Flowtypesoperatebysensing&indicating
themomentaryrateofflow.
Systems of Pneumatic comparators
❑Compressedairafterfiltering&
pressureregulationflowsthrougha
glasstubewithasmallmetalfloat.
❑Theairthenpassesthroughaplastic
tubetothegaugeheadwithtwo
diametricallyoppositeorificesforthe
airtoescape.

128. Linear and Angular Measurement
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Comparators –Pneumatic Comparators
Systems of Pneumatic comparators

129. Linear and Angular Measurement
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Comparators –Pneumatic Comparators
Back pressure type Pneumatic Comparators

130. Linear and Angular Measurement
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Comparators –Pneumatic Comparators
Back pressure type Pneumatic ComparatorsConstant
pressure
source
P1 P2
To atmosphere
O
c mO
Principle of back pressure type Pneumatic comparator
Back Pressure Circuit
Air supply
Filter
Regulator
Bourdon tube
Scale
Work piece
Measuring head